System and method for controlled battery heating

Abstract

Systems and methods for low temperature charging of a battery are provided, which can be performed alone or in combination with heating the battery. In some aspects, the low temperature charging method involves obtaining a susceptance response of a battery, and varying a charging signal delivered to the battery as the susceptance response of the battery changes. It will be appreciated that the change in susceptance is related to a phase change of the battery electrolyte, for example, when the battery warms from a low temperature at which the electrolyte is partially or completely frozen (solid) to a higher temperature at which the electrolyte changes to a liquid state. As the electrolyte changes from solid to liquid, the charge can increase as the electrolyte thaws, as understood from the change in the susceptance response.

Description

Cross-references to related applications

[0001] This Patent Cooperation Treaty (PCT) application relates to U.S. Provisional Patent Application No. 63 / 543,921, filed October 12, 2023, entitled "Systems and Methods for Controlled Battery Heating," and claims priority to the aforementioned U.S. Provisional Patent Application, the entire disclosure of which is incorporated herein by reference for all purposes as if fully set forth herein. Technical Field

[0002] Embodiments of the present invention generally relate to systems and methods for heating batteries and / or charging or discharging batteries. Background Technology

[0003] Numerous different types of electric devices, such as power tools, mobile computing and communication devices, portable electronic devices, and all kinds of electric vehicles, including motorcycles and bicycles, use rechargeable batteries as their power source. Rechargeable batteries are limited by their finite capacity and must be recharged after depletion. Recharging batteries can be inconvenient because the electric device must typically remain stationary during the time required for recharging. Depending on the battery size, recharging can take several hours. Furthermore, battery charging is often accompanied by degradation of battery performance. Therefore, considerable effort has been invested in developing battery charging technologies to reduce the time required for battery recharging, improve battery performance, and reduce battery degradation caused by charging.

[0004] Various battery types containing lithium-based batteries generally cannot be charged at low temperatures without damaging the cells. In some cases, especially in liquid electrolyte batteries, the electrolyte may freeze. Attempting to charge when the electrolyte is frozen, or additionally when the battery temperature is below a certain threshold, can damage the battery through the electrode plating. This is clearly a problem in many applications where the battery is discharging but the temperature is too low for regular charging.

[0005] It is with these observations, as well as other factors, in mind that the various aspects of this disclosure have been conceived. Summary of the Invention

[0006] One aspect of this disclosure relates to a system for heating a battery, the system including a processor in communication with a circuit, wherein the processor is configured to execute instructions for heating the battery by means of a control circuit alternating between supplying current to the battery and absorbing current from the battery, and to heat the battery by a combination of supplying current to the battery and absorbing current from the battery.

[0007] Another aspect of this disclosure relates to a battery-powered system including a battery and a processor operatively in communication with a charging circuit of the battery, the processor being operatively coupled to the charging circuit to control at least one harmonic component of a discharge signal from the battery. The system may further include a signal conditioning element positioned between the battery and a load system, the signal conditioning element receiving the discharge signal from the battery and providing a DC signal to the load system.

[0008] Another aspect of this disclosure relates to a method for charging a battery, the method comprising, in response to obtaining information indicating whether the battery is rechargeable, alternating between supplying current to the battery and drawing current from the battery to heat the battery. The method may further include receiving a temperature measurement of the battery, the temperature measurement providing information indicating whether the battery is rechargeable. In one possible instance, obtaining a response from the battery based on the application of a signal having known harmonics provides information indicating whether the battery is rechargeable. In another possible instance, the response is an impedance response, and the information is the correlation between the battery temperature and the impedance response. In various embodiments, impedance or admittance response is discussed, and it should be appreciated that the term impedance response encompasses its inverse admittance response, and the term admittance or admittance response similarly encompasses its inverse impedance or impedance response.

[0009] Another aspect of this disclosure relates to a method for charging a battery, the method comprising, in response to obtaining information indicating whether the battery is rechargeable, applying a harmonically tuned signal to the battery, wherein the harmonically tuned signal comprises at least one harmonic associated with a conductance response and a reactance response to heat the battery. The method may further involve receiving a temperature measurement of the battery, the temperature measurement providing information indicating whether the battery is rechargeable. Another example may involve obtaining a response from the battery based on the application of a signal having known harmonics, thereby providing information indicating whether the battery is rechargeable. In one example, the response is an impedance response, and the information is the correlation between the battery temperature and the impedance response. At least one harmonic may be a frequency higher than the battery's dynamics and diffusion processes. If the signal comprises multiple harmonics, the set of harmonics may be a frequency higher than the battery's dynamics and diffusion processes.

[0010] Another aspect of this disclosure relates to a method of heating a battery, the method comprising generating a repetitive signal to be applied to the battery, the repetitive signal comprising a first portion and a second portion within a cycle, the first portion defining a sinusoidally shaped leading edge rising to a body portion terminating at a falling edge, the first portion defining a first percentage of the cycle, the second portion comprising alternating current following the falling edge of the first portion, the second portion defining a second percentage of the cycle, wherein the first percentage and the second percentage constitute the cycle.

[0011] Another aspect of this disclosure relates to a method for charging a battery, the method comprising applying a probe signal to the battery, the probe signal including a plurality of harmonics, the plurality of harmonics including at least a first harmonic and a second harmonic. The system / method further relates to: obtaining a voltage response and a current response at the battery based on the probe signal; and, based on the voltage response and the current response, generating an impedance spectrum comprising a first impedance including at least a first harmonic and a second impedance including a second harmonic, the first impedance being less than the second impedance; and generating a charging signal to be applied to the battery, the charging signal comprising a sinusoidally shaped leading edge of the frequency of the first harmonic.

[0012] Another aspect of this disclosure relates to a method for heating a battery, the method comprising applying alternating current to the battery to heat the battery, wherein the alternating current is at a frequency greater than the inflection point of the conductance response or less than the inflection point of the susceptance response. More specifically, the frequency is greater than the inflection point of the conductance response and less than the inflection point of the susceptance response.

[0013] Another aspect of this disclosure relates to a method for heating a battery, the method comprising applying alternating current to the battery to heat the battery, the alternating current being at a frequency at which the battery’s conductivity response is decreasing and the battery’s susceptance response is increasing.

[0014] Another aspect of this disclosure relates to a method for charging a low-temperature battery, the method comprising: obtaining a susceptance response of the battery, and, when the susceptance response of the battery changes, altering a charging signal transmitted to the battery. The change in susceptance response is related to a phase transition of the battery's electrolyte (e.g., a change in some or all of the battery electrolyte from a solid to a liquid state). The change in the charging signal may be an increase in the magnitude of the charging current.

[0015] These and other features of this disclosure are discussed in more detail below. Attached Figure Description

[0016] From the following description of embodiments of the inventive concepts, the various objects, features, and advantages set forth herein will become apparent, as illustrated in the accompanying drawings. It should be noted that the drawings are not necessarily drawn to scale or include every detail, and may represent various features of the embodiments, with the emphasis on illustrating the principles and other aspects of the inventive concepts. Furthermore, in the drawings, the same reference numerals throughout different views may refer to the same or similar portions. It is intended that the embodiments and drawings disclosed herein be considered illustrative rather than restrictive.

[0017] Figure 1 This is a circuit diagram of a battery heating and charging system according to one embodiment, which further illustrates the charging path and load path starting from the power source.

[0018] Figure 2 yes Figure 1The circuit diagram of the battery heating and charging system is shown, which further illustrates the discharge path starting from the battery and the load path starting from the power rail containing the power source.

[0019] Figure 3 yes Figure 1 and Figure 2 The circuit diagram of the battery heating and charging system further illustrates the charging path and load path starting from the power rail (e.g., the capacitor on the power rail), where the power source is not supplying energy (e.g., current).

[0020] Figure 4 This is a signal diagram of a first example heating signal according to one embodiment, including a symmetrically shaped charging current portion and a discharging current portion.

[0021] Figure 5 This is a signal diagram of a second example of a heating signal including a charging current portion and a discharging current portion with asymmetrical shapes, according to one embodiment.

[0022] Figure 6 This is a signal diagram of a third example of a heating signal including charging current portions and discharging current portions of different shapes, according to one embodiment.

[0023] Figure 7 This is an example of a characteristic curve that shows a battery being heated until the battery temperature allows charging.

[0024] Figure 8 This is a flowchart of a method for heating a battery according to one embodiment.

[0025] Figure 9A This is a signal diagram of a first combined charging and heating signal according to one embodiment.

[0026] Figure 9B This is a signal diagram of a second combined charging and heating signal according to one embodiment.

[0027] Figure 10A This is a signal diagram of a charging signal including a 0 A rest period according to one embodiment.

[0028] Figure 10B It is a signal diagram according to one embodiment, which includes a charging signal with a rest period having a non-zero current.

[0029] Figure 11 This is a flowchart of a method for shaping a charging signal according to one embodiment.

[0030] Figure 12 This is a flowchart of a method for identifying charging current levels that take battery temperature into account, according to one embodiment.

[0031] Figure 13 This is a system diagram that includes a signal conditioning element for converting unconventional, non-DC current from a battery into a signal to power conversion or other load consumption that typically requires a DC signal.

[0032] Figure 14A This is a conductivity response diagram of a lithium-ion battery in one embodiment, the conductivity response being used to establish the frequency of the heating signal.

[0033] Figure 14B This is a susceptance response diagram of a lithium-ion battery in one embodiment, whereby the susceptance response is used to establish the frequency of the heating signal.

[0034] Figure 15 This is a diagram illustrating an example of a computing system that can be used to implement embodiments of the present disclosure.

[0035] Figure 16 This is a graph illustrating the correlation between peak susceptance and phase transition within the battery electrolyte. Detailed Implementation

[0036] This document discloses systems, circuits, and methods for heating and charging (recharging) batteries. The terms charging and recharging are used synonymously herein. Aspects of this disclosure may individually or in combination offer several advantages over conventional charging. For example, the charging techniques described herein allow the battery to be heated to a level sufficient for charging. In some cases, the battery temperature is monitored, and when said battery temperature is below a threshold, the system initiates a heating sequence before charging and transitions to a charging sequence when the battery is sufficiently heated. Temperature thresholds can be customized for various battery chemistry types. In one instance, the temperature thresholds used for heating, the combination of heating and charging, and charging may depend on or be related to the freezing temperature of the liquid electrolyte, but various possible temperature parameters and thresholds are envisioned. Furthermore, some battery chemistry types (such as those in solid-state batteries) do not have a liquid electrolyte but are still affected by temperature, making charging at excessively low temperatures potentially damaging the battery. The system may also involve circuitry for charging techniques that allow for a reduction in the rate of anode damage. These circuitry elements can control the heat generated by the battery by generating heat when charging has begun or by minimizing heat generation above a certain level. This can have several subsequent effects, such as reducing damage to electrodes and other battery components, and reducing the risk of fire or short circuits.

[0037] When discharging a battery, whether for heating or powering a load, aspects of this disclosure further relate to discharge signal conditioning elements positioned between the battery and the load or integrated within the load. Conventionally, a battery discharges to a load via a DC signal, or, for example, a DC signal from the battery is converted to an AC signal by an inverter to power an AC motor. However, whether for heating or other purposes, aspects of this disclosure relate to unconventional, non-DC discharge signals. The discharge signal conditioning elements are used to regulate unconventional discharge signals suitable for loads or for components that power loads using energy from the battery.

[0038] In one example, the various embodiments discussed herein manage the energy entering and leaving a battery by generating controllably shaped charging or discharging signals. The shape can be tuned based on the battery's impedance effects to various harmonics. In some examples, during heating, the shape, which may include harmonic aspects during charging or discharging, is tailored to heat the battery and minimize damage or achieve other effects. In some examples, during charging, the shape or content of the charging signal (which may also include harmonic aspects) is optimized for charging. During heating, the system can select harmonic properties associated with relatively high impedance, rather than charging where the system can control the charging signal to include harmonic properties associated with relatively low impedance.

[0039] The system may further utilize models of one or more components of a charge / discharge signal shaping circuit. Conventional charging techniques (DC techniques), such as constant current or constant voltage, do not involve charge signal shaping and are therefore relatively simple to control, and do not require the charge and discharge signal shaping techniques discussed herein. The model can be used to verify and / or adjust the control of the signals generating the signals entering and exiting the battery, as well as combinations that may exist during heating. In some examples, aspects of the shape and / or content of the charge signal may correspond to one (or more) harmonics associated with optimal energy transfer to the battery, but the system's objective is to efficiently generate and apply any arbitrarily shaped charge signal to the battery, and other objectives. In other examples, particularly concerning battery heating that may occur before charging, shaping and / or defining signals designed to induce heating and minimize or eliminate charging during the time the battery is heated to prepare for charging (or discharging) involves controlling the shape or signal content, which may be any arbitrary shape defined by the control and, in some examples, includes defined harmonic content.

[0040] In one possible implementation, using a model to determine the feedforward technique for the control signals used to define the charging / discharging signals offers several advantages, including accuracy and speed of signal adjustment. Furthermore, the arrangement can be operated with fewer components than other methods, thus reducing costs and occupying less printed circuit board space, among other advantages. Regardless of whether a model is used, the method may further include adjusting the signals from heating to charging when the battery reaches an appropriate temperature, followed by signal adjustment during battery charging.

[0041] Regardless of whether a model is used, various aspects of the system can be further incorporated into both the heating phase and the transition to the charging phase, through feedback on temperature and other battery parameters during the charging phase. Feedback, alone or in combination with the model, allows the system to adjust for component drift, the effects of temperature or other effects on circuit components, battery changes, and to periodically provide additional data to the system and / or model to modify their outputs, as well as other operations. Furthermore, the system can use battery temperature to select between heating or charging, and in some cases, transition between a heating phase and a phase where charging is optimized without heating; this can include transition phases for both heating and charging.

[0042] The term "battery" in this art and throughout this document can be used in various ways and can refer to an individual cell having an anode and cathode separated by a solid or liquid electrolyte, as well as a collection of such cells connected in various arrangements. A battery or battery cell is a form of electrochemical device. A battery typically comprises repeating units of a countercharge source and an electrode layer separated by an ionic conductive barrier, often a saturated liquid or polymer film containing an electrolyte. These layers are made thin so that multiple cells can occupy the volume of the battery, thereby increasing the usable power of the battery per stacked cell. While many of the examples discussed herein apply to batteries, it should be understood that the systems and methods described are applicable to many different types of batteries, from individual cells to batteries involving possible different interconnections of cells (e.g., parallel coupling, series coupling, and parallel and series coupling). For example, the systems and methods discussed herein can be applied to battery packs comprising a number of cells arranged to provide a defined pack voltage, output current, and / or capacity. Furthermore, the embodiments discussed herein can be applied to different types of electrochemical devices, such as various types of lithium batteries, including but not limited to lithium metal and lithium-ion batteries, lead-acid batteries, various types of nickel batteries, and solid-state batteries, to name just a few. The various embodiments discussed herein can also be applied to different battery arrangements, such as button or "coin" type batteries, cylindrical cells, pouch cells, and prismatic cells.

[0043] Figures 1 to 3A battery heating and charging circuit topology according to an embodiment of this disclosure is shown. The arrows shown in the figure define the current flow paths during different operating states of the system. Figure 1 In the example, the system is shown in a configuration that supplies current (charging) to the battery and powers the load. Figure 2 In the diagram, the system is shown in a configuration where current is drawn from the battery (discharging or absorbing), flows to a capacitor on a rail, and supplies power to the load when the power is on (connected to the rail). Figure 3 In the example, the system is shown in a configuration where it draws current from a capacitor on a battery rail and supplies power to the load when the power is off (not connected to the rail). Figure 2 and Figure 3 Both also include arrows showing a "blip" path to the lower second transistor, which is the path for the initial discharge current.

[0044] Figure 1 as well as Figure 2 and Figure 3This is a schematic diagram illustrating an example charging signal generator arrangement 100 for heating, charging, and / or discharging battery 104. The generator includes a processing unit, or more generally a control unit 106, which may include a controller, such as a microcontroller, field-programmable gate array (FPGA), application-specific integrated circuit (ASIC), microprocessor, combination thereof, or other processing arrangement, that can communicate with a signal generator 108 that generates control over charging signals generated from charging signal shaping circuitry 110. The controller may communicate with a model, which may be part of the generator, to generate control commands to the charging signal shaping circuitry. The control unit, including the controller and model (if present), may be an integrated unit. The system may also receive feedback from battery measurement unit 116 containing battery measurements, such as current and / or voltage measurements at the battery terminals of battery 104 in the presence of a signal (heating, charging, and / or discharging), and these battery measurements can be used to obtain impedance measurements and / or influence heating or charging control. Typically, the generator may also include or be operatively coupled to a power supply 118, which may be a voltage source or a current source. In one embodiment, power supply 118 is a direct current (DC) current or voltage source, but an alternating current (AC) source is also contemplated. Among various alternatives, power supply 118 may comprise a DC source providing unidirectional current, an AC source providing bidirectional current, or a power source providing ripple current (e.g., an AC signal with DC bias such that the current is unidirectional). Typically, power supply 118 supplies charging energy, such as current, which may be shaped or otherwise defined by control unit 106 and circuit 110 to generate a controllably shaped charging signal for heating, charging, and / or discharging battery 104. In one example, controller 106 may provide one or more inputs to signal generator 108, which controls switches to generate pulses to circuit 110, which may also be referred to as a filter that generates a shaped signal at the battery.

[0045] In some examples, the signal shaping circuit 110 can alter the energy from the power supply 118 to generate a signal shaped based on conditions at the battery 104, such as a signal at least partially corresponding to one or more harmonics based on the impedance when a signal including harmonics or harmonic properties is applied to the battery 104. Figure 1In one example, circuit 100 may further include a battery measurement unit 116 connected to battery 104 to measure cell voltage and / or charging current, as well as other battery properties such as temperature, and to measure, calculate, or otherwise obtain the impedance of battery 104 based on the aforementioned measurements. In one example, battery characteristics may be measured based on signals entering and exiting the battery. In another example, battery cell characteristics may be measured as part of a routine of applying signals with varying frequency attributes to generate a range of battery cell characteristic values ​​associated with different frequency attributes in order to characterize the battery. This part may be performed periodically before heating, charging, or discharging, during charging, and during charging, and may be used in combination with lookup techniques and other techniques. Battery characteristics may vary based on a number of physical and chemical characteristics of the battery, including the battery's state of charge and / or temperature. Thus, battery measurement circuit 116 may be controlled by controller 106 to determine various battery characteristic values ​​of battery 104 during heating, battery recharging, and / or power supply to a load, and at other times, and to provide the measured battery characteristic values ​​to controller 106 or other parts of generator 100.

[0046] During charging, controller 106 can generate a desired charging signal for efficient charging of battery 104. For example, controller 106 can generate or select a charging signal having properties corresponding to harmonics associated with an optimal impedance (which may be an impedance range) for energy transfer, characterized by an understanding of the impedance effect of the signal on the battery, using a determined impedance of battery 104 or a signal definition based on an understanding of the impedance effect of the signal on the battery. This optimal impedance may be associated with a minimum impedance value of battery 104. Thus, controller 106 can execute a charging signal algorithm that outputs a charging signal shape based on measured, characterized, and / or estimated charging conditions of battery 104. Generally, a signal generator controls a switch to generate a pulse sequence at node 136, which is converted into a charging signal shape by circuit 110. Similarly, during heating, the battery can be characterized based on temperature to understand the impedance effect of the charging or discharging signal on the battery and the signal controlled based on this impedance effect. Here, node 136 can be similarly controlled, but with current having defined impedance properties supplied to and absorbed from the battery via circuit 110. It should be recognized that heating can also involve the transition of current into and out of the battery, characterized by optimized heating, minimizing or eliminating plating, and minimizing any energy storage in the battery during the heating sequence. Signal generator 108 may generate one or more control signals based on a heating or charging signal algorithm and provide those control signals to signal shaping unit 110. The control signals may shape or otherwise define the signals entering and exiting the battery to approximate the shaped charging signal determined, selected, or otherwise obtained by controller 106, and other functions. Charging signal shaping circuitry 110 may further filter out any unwanted frequency attributes from the signal. In some examples, the shaped charging signal may be any arbitrarily shaped signal such that, whether heating, charging, or discharging, the signal is not a constant DC signal and does not conform to conventional repetitive charging signals, such as repetitive square wave or triangular wave charging signals.

[0047] According to one embodiment, Figures 1 to 3 The circuit includes switching elements 112 and 114, which can be considered as part of circuit 110, to generate an initial sequence of controlled pulses at node 136. These controlled pulses are then converted by filter 110 into shaped signals to generate signals applied to or from the battery. The switching elements can also be used to generate a discharge signal from the battery by similarly generating pulses at node 136 in the absence of charging current on rail 120.

[0048] As described, circuit 100 may include one or more components to shape a signal that intentionally heats the battery through a coordinated combination of charging and discharging at battery 104. Circuit 100 may include a first switching element (e.g., transistor 112) and a second switching element (e.g., transistor 114), wherein the first switching element is connected to a power rail, thereby connecting to a power supply 118 during charging and coupling to a capacitor 122 on the rail during discharging. The capacitor may have various functions, including discharge signal conditioning as discussed in more detail below. The first transistor 112 may receive an input signal, such as a pulse width modulation (PWM) control signal 130, to operate the first transistor 112 as a switching device or component. Typically, the first transistor 112 may be any type of transistor, such as a FET, or more specifically, a MOSFET, GaN FET, silicon carbide-based FET, or any type of controllable switching element. For example, the first transistor 112 may be an FET, wherein the drain node is connected to a first inductor 140, the source is connected to the rail, and the gate receives the control signal 130 from the signal generator 110. In various embodiments, circuit 110 also includes inductor 140, but may also have various other possible inductive elements. When operated in a bidirectional manner for both charging and discharging, and as described in more detail below, circuit 110, in particular the combination of inductors 142, 140 and capacitor 148, can be considered a raised topology when controlling the current from the battery during the heating discharge phase or more generally during normal operation when drawing current to the load.

[0049] When heating, the system can be operated to supply current to the battery (typically referred to as charging, but it is recognized that during heating, the system optimizes the source current for heating rather than charging) and to draw current from the battery (discharging, similarly recognized that during heating, the system optimizes the current from the battery for heating rather than powering the load). The system can control the heating sequence to rapidly switch between supplying current to the battery and drawing current from the battery. To supply current (charging), the circuit controller 106 can provide a control signal 130 to control the operation of the first transistor 112 as a switch, which, when closed, connects the first inductor 140 to the rail 120, such that current from the power source (and / or from the capacitor 122) flows through the first inductor 140 and the second inductor 142 (if present), to the battery. The second transistor 114 can receive the second input signal 132 and can also be connected at node 136 to the drain of the first transistor 112. In the charging case, and in some examples, the second input signal 132 may be a PWM signal opposite to the first control signal 130 to the first transistor 112, so that the switching is coordinated by turning on one transistor and turning off the other transistor.

[0050] One or more inductor values, one or more capacitor values, the timing and frequency of the actuating transistor, and other factors can be customized to generate waveforms, particularly those with controlled harmonics to the battery for heating. (Reference) Figures 4 to 6 The example signal shown, when current is supplied, can be a series of pulses at node 136 between 0 volts and approximately the rail voltage. The pulses at node 136 can have varying duty cycles and can be generated at varying frequencies. However, generally, the pulses are generated to produce a signal that is the same as or nearly the same as the expected current signal flowing into and out of the battery. Therefore, for example, such as... Figures 4 to 6 The signal of any of those signals will be located at node 138 based on a combination of pulses present at node 136, which are then shaped by filter arrangement 110 into a signal at 138. Depending on the signal, pulses of 10 s to 1000 s (or longer) can be generated to form the desired charging signal.

[0051] The discharge sequence involves initially turning off the upper first transistor 112 and turning on the lower second transistor 114. The second transistor may be briefly turned on only for a sufficient time to initiate current from the battery to inductors 142, 140. The transistor can be controlled to eliminate or minimize current flowing through the second inductor to ground. When current from the battery is initiated (discharge), the second transistor turns off and the upper transistor 112 turns on, where the power supply is turned off or on to drive current to rail capacitor 122 and / or load 144. Once current from the battery is initiated, a pulse can be controlled at node 136 to similarly shape the discharge signal or the discharged portion of the signal. Depending on the type of power required by the load, the system may include some form of power conversion element 146. The system can operate with the power supply on or off. If off, current is directed to the capacitor and / or load. If switched on, the power supply may include the functionality to coordinate the power supply to maintain the rail voltage, and if the discharge of current increases the rail voltage above a certain level, it may enable the power supply to synchronously maintain the set rail voltage.

[0052] Overall, during heating, the controllable system rapidly switches between supplying energy to and absorbing energy from the battery. Furthermore, operable circuitry shapes the current to and / or from the battery via pulses at control node 136. Through these features, individually or in various combinations, the battery can be heated to a level sufficient to induce charging. It should be recognized that different battery types have different temperature thresholds for appropriate operation involving charging or supplying power to a load. Additionally, or individually, heating may occur with little or no charging of the battery, where energy is essentially concentrated for heating, thereby minimizing or avoiding damage to plating or other electrodes, switching to charging and changing the signal to optimal charging or switching to one that does not generate excessive heat, achieving optimal circuit efficiency using components with the multifunctional functions of controlled heating and controlled charging, and other benefits.

[0053] As described, the system may include a first capacitor 122 connected between the power rail and ground. The capacitor can be used to store discharge energy, which can then be used alone or in combination with power from the source to supply power to a load during charging. As discussed in more detail below, the capacitor 122 can also be used to regulate the discharge signal before it is further processed by a power converter or directly supplies power to the load. Additionally, some of the energy required for the charging waveform can be provided by a combination of the source and capacitor 122. In some examples, discharge energy from the battery stored in the capacitor can be returned to the battery during heating and when the system is supplying current to the battery. The circuit may also include a second capacitor 148 connected between a first inductor 140 and a second inductor 142 to ground. The second inductor 142 may be connected to a battery, for example, the anode of battery 104.

[0054] After heating and during charging or supplying a load from the battery, the system can be substantially operated to prevent rapid changes in signals applied to or from the battery 104. During charging operation, the filter can also convert pulses at its input into a charging signal and filter out any unwanted high-frequency noise from the battery. For example, when the first transistor 112 is closed based on control signal 130, the first inductor 140 and the second inductor 142 can prevent a rapid increase in the current flowing to the battery 104. Furthermore, inductor 140, or inductors 140 and 142 individually or in combination with capacitor 148, can shape the waveform applied to the battery, and control of the signal applied to the inductors enables controlled waveform shaping. These components can be similarly used to control the shape of the discharge waveform. In another example, when the first transistor 112 is closed, capacitor 148 can store energy from the power source. When the first transistor 112 is turned off (which may be accompanied by the closing of transistor 114), capacitor 148 can provide a small current to battery 104 through second inductor 142 to counteract an immediate drop in current to the battery, and can similarly be used to controllably shape the waveform applied to the battery, particularly to avoid sharp negative transitions during normal charging after heating. The filter circuit also removes other unwanted signals, such as noise that may contain relatively high-frequency noise.

[0055] It should be understood that the system may contain more or fewer components. For example, one or more components of the filter circuit may be removed or changed as needed to filter or define signals entering or leaving the battery. Many other types of components and / or configurations of components may also be included with or associated with the system.

[0056] Figures 4 to 6 Example heating waveforms that could be alternatives are shown. In each case, the controlled waveform transitions between the charging or supply section 410 (510, 610) and the discharging or absorption section 420 (520, 620). At the high level, Figure 4 The heating waveform exhibits a sine curve, where the positive portion of the waveform represents the current entering the battery (e.g., to...). Figure 1 The current path of the battery), and the negative part of the waveform is the current from the battery (e.g., Figure 2 or Figure 3 The current path from the battery to the capacitor on the rail should be noted; the current path to ground through the lower transistor is intended only to initiate the discharge current path to the rail capacitor. The shape of the current to or from the battery is controlled by a pulse at node 136. That is, by controlling the pulse frequency, pulse width, and / or voltage level, the system can shape the waveforms entering and leaving the battery.

[0057] Figure 5The heating waveform exhibits an asymmetrical sine curve, where the current to the battery (the positive portion of the waveform) has a larger absolute amplitude compared to the current from the battery. In some cases, particularly in fully or nearly fully discharged batteries, it may be necessary to add slightly more energy than is discharged to avoid over-discharging the battery. Compared to the current from the battery, Figure 6 The heating waveform has an arbitrary (albeit controlled) shape for the current to the battery. Furthermore, the shape is inconsistent from one arbitrarily shaped input current portion to the next arbitrarily shaped input current portion and from one arbitrarily shaped output current portion to the next output current portion.

[0058] The frequency of the supply-to-absorption transition, the shape of the supply and absorption signals, and various other aspects of the heating sequence can vary. The shape of any part of the signal (whether to or from the battery) can be based on the battery's impedance to the signal being applied to or from the battery. Signal definitions can be preset. Depending on various battery parameters including SOC, temperature, cycle number, battery chemistry and configuration, and many other possible attributes, the signal definition can also be algorithmic. The signal definition can also vary during heating and charging. As mentioned herein, impedance and harmonics can affect the selection or definition of the charging signal. As a general concept, a signal definition associated with relatively high impedance and associated harmonics can be selected for the heating sequence, while relatively low impedance and associated harmonics are used for charging or discharging to power the load sequence. It should also be noted that a relatively rapid change between supplying current to the battery and absorbing current from the battery can be used for heating, so that once a sufficient temperature is reached, the system transitions from absorbing current (during charging) so that charging will not damage the battery.

[0059] In a heating sequence, one or more properties of the charging and / or discharging portions of the signal can be customized to have relatively high impedance characteristics, compared to a charging sequence where customizing the charging signal to have relatively low impedance characteristics would be optimal. Heat can be generated without initiating any substantial battery charging by briefly injecting current into the cell and then briefly drawing current out of the cell. The transition frequency between the currents entering and leaving the battery may affect optimal heating if the harmonics associated with the transition are relatively high, causing energy to be primarily used for heating. Alternatively, the charging or discharging portion of the waveform can be defined as containing harmonic properties associated with relatively high impedance. Thus, unlike charging, charging capacitors during discharging, and / or supplying power to a load during discharging, the current energy entering or leaving the battery can be primarily dissipated as heat due to the relatively high impedance (typically resistance).

[0060] Battery temperature can be assessed in various ways. In one example, the system can use a temperature sensor located at the battery to assess the battery temperature. Various temperature sensors can be used, including those in contact with the battery, those in contact with the battery terminals, those positioned within the casing containing the battery, or those in other forms. Examples of various sensors include thermistors, thermocouples, infrared sensors, diodes, and transistors, or any of countless different types of temperature sensors.

[0061] In another instance, a battery response with harmonic or other frequency properties can be used to probe the battery's internal temperature, or more generally, its ability to accept charge, which may be the same as or slightly different from a measurement of temperature (particularly the battery's external temperature). The use of harmonic responses can also be used to more uniformly assess a battery's ability to accept charge.

[0062] In one particular instance, the system uses a characterization of the battery's response to various harmonics at different temperatures. This characterization can be applied to any given battery type or specific battery. The characterization can be stored in a lookup table accessible to the processor in memory by setting thresholds, etc. In this particular instance, it should be understood that various battery chemistry and configurations have different impedance responses at different temperatures. Therefore, for a given battery, the impedance response of a signal applied to the battery with a specific harmonic frequency differs based on temperature. In some examples, temperature sensing signals at different discrete frequencies can be used to generate an impedance response, which is then compared to the characterization to assess the temperature, or more generally, the battery's ability to accept charging, and thus whether heating is required before charging can begin. The impedance response can be characterized by the imaginary component, the real component, or both the imaginary and real components of the impedance. In some embodiments, the impedance response can be used alone or in combination with a sensed battery temperature measurement to determine whether the battery should be heated or can be charged. Similarly, other frequency-based responses or impedance derivatives (e.g., susceptance, admittance, and capacitance) can be used alone or in place of directly sensed temperature measurements to determine whether the system should be configured to heat the battery.

[0063] Generally, in various embodiments considering impedance values, the techniques evaluate harmonic values, which are associated with a particular impedance individually or in combination. Given the generally inverse relationship, the term "impedance" as used herein may include its inverse admittance, encompassing its individual or combined components of conductance and susceptance.

[0064] In another aspect, battery heating can be achieved by controllably charging or discharging the battery, or a combination thereof as discussed above. In this example, the signal (whether a charging signal, a discharging signal, or a signal alternating between charging (supplying current to the battery) and discharging (absorbing current from the battery)) consists of one or more harmonics tuned to optimize the signal for relatively high conductivity and relatively high reactance in the battery. Using a charging signal as an example, the optimized combination (or balance) between high conductivity and high reactance generates heat in the battery. In this example, the signal consists of harmonics such that harmonics can be identified in one or more frequency domain representations (or transformations) of the signal. The tuned signal can also be shaped to reflect various harmonic properties. In a fairly simple example, the signal can also consist of discrete sine waves at specific frequencies, such that it is both composed of harmonics and shaped in harmonic form. Generally, even with very high conductivity, the signal magnitude may be higher than that supported by many charging environments to generate sufficient heat if the reactance is too low. Similarly, if the conductivity is too low, even with high reactance, excessive energy may be required to convert into heat. Therefore, for any initial temperature and battery chemistry, the system selects a charging signal with harmonics that balances high conductivity and high reactance.

[0065] In a specific instance, a given type of battery can be characterized at various temperatures by evaluating a signal composed of various combinations of harmonics to identify one or more signals that balance relatively high conductance and relatively high reactance to achieve sufficient heating. Characterization can also determine the time required for a heating signal to be applied to reach a state sufficient to initiate heating. The balance can further consider properties that minimize the energy used for actual charging, thus concentrating energy effectively for heating. The same technique can be applied to generate discharge signal harmonics that may be the same as or different from the charging signal at various temperatures.

[0066] Harmonic frequencies are typically higher than the kinetics and diffusion processes in any given battery for which the signal is optimized for heating. Generally, frequencies faster than the kinetic response of the electrochemical process are chosen so that voltage and current values ​​do not adversely affect the battery's electrodes or interfaces during heating. Therefore, a relatively high voltage signal could be used during heating (e.g., 6 V when a maximum of approximately 4 V is typically specified), which would generally result in plating, but would not cause plating because the signal consists of harmonics or a harmonic spectrum that are faster than the kinetics. Nevertheless, in many cases, signals falling within a relatively low specified charge (or discharge) voltage level are selected. Additionally, utilizing the various heating techniques described herein, in some examples, the system is optimized to heat without transferring any net charge. In such examples, the system controls the signal to charge and discharge with relatively uniform total energy, such that the signals cancel each other out, thereby resolving any differences in energy conversion efficiency between the charged and discharged portions at any given temperature.

[0067] Figure 7 This is an example of a characteristic curve showing the process of heating a battery until its temperature allows charging. In this example, the initial battery temperature is -20°C, and the State of Charge (SOC) is 10%. The battery is heated until it reaches approximately -15°C, at which point charging can begin. It can be seen that when the battery temperature rises by approximately 5°C before charging begins, the SOC remains at approximately 10%. It can also be seen that the battery temperature continues to rise until the SOC reaches 100%.

[0068] In many conventional battery-powered systems, the system relies on DC discharge current from the battery to provide power to a load. The battery can be a single cell or a small number of cells, as in power tools, vacuum cleaners, portable speaker systems, etc., or it can be a large interconnected array of cells, as found in some types of electric vehicles. The arrangement and type of cells will generally depend, at least in part, on the specified capacity of the system in which the battery operates, the required discharge current of the system's load, and other factors. In any case, a conventional battery provides DC discharge current when supplying power to a load. When an AC signal is required to drive the load (e.g., an AC motor), a converter, such as converter 146, is used to convert the battery's DC output into the AC signal required by the load.

[0069] For battery heating and heating-based charging control, and for defining the shape of a harmonic-tuned charging signal during or after heating, or otherwise, aspects of this disclosure relate to unique battery charging and heating sequences based on the battery's initial temperature and expected temperature changes during charging. Aspects of this disclosure further relate to techniques for shaping the charging signal to achieve optimal charging (whether heating, charging, or a combination of both). The charging signal may have a harmonic-shaped leading edge. In other words, the leading edge of the charging signal may be defined by the frequency of a sine curve and may have a corresponding shape. Aspects of this disclosure further relate to methods for determining, alone or in combination with any one or both of the heating sequence and the shaped charging signal, the maximum charging current that can be applied based on the current state of the battery, taking into account battery heating and / or battery temperature.

[0070] In one aspect, the charging system is configured to assess the battery temperature and determine a charging sequence based on said battery temperature. As discussed above, in some cases, the battery temperature may be at or below a certain threshold where charging might damage the battery or may be completely ineffective. In this case, the system may generate a signal to heat the battery. As mentioned above, various possible heating signals are possible. When the battery temperature rises above the threshold, the system may begin charging the battery while continuing to heat it. Finally, if the temperature rises above a second threshold, the system may stop heating and switch to a signal solely intended for charging the battery. However, it should be recognized that charging the battery often results in battery heating. One benefit of harmonic-tuned charging signals is their optimized use of energy for charging, thus resulting in less heating compared to various conventional charging techniques. Consequently, more current can be supplied during charging than in conventional systems because the charging technique generates less heat, among other advantages.

[0071] Now we're turning to specific methods for heating batteries. Figure 8 This is a flowchart illustrating a possible example of a method for heating a battery, and Figure 9A and Figure 9B A possible example of combined charging and heating signals is shown. (For use with...) Figure 9A and Figure 9B The magnitude of the current signal will depend on the cell capacity and the external temperature. For example, for some cell types, the peak current will be approximately 6 A to 12 A for 3 Ah or 4 Ah cells. In some cases, higher magnitudes are possible for heating, and the battery will heat up faster (compared to lower magnitude signals). Magnitudes higher than those specified for charging are possible, and such magnitudes can potentially be relatively large due to the selectable heating frequency that does not affect the electrochemical process, for example, a signal at 60 App or greater.

[0072] refer to Figure 8 First, the charging system obtains the battery temperature (operation 800). The battery temperature can be obtained in several ways. As discussed above, it can be obtained from one or more temperature sensors located in or at the battery (or battery pack, in which case more than one temperature sensor may be used). In addition to the battery temperature, the system can also obtain the ambient temperature. It should be recognized that the battery temperature can be calculated from other information besides the sensed battery temperature.

[0073] Depending on the battery type, the system can identify a first temperature T1 at or below which the battery should be heated before charging, a temperature range between a relatively lower first temperature T1 and a second relatively higher upper temperature T2 (between the first temperature and the upper temperature, the system can begin charging and continue heating), and an upper temperature T2 above which heating is no longer needed and the system can charge without continuous, purposeful heating. For illustrative purposes, the method and system are discussed with reference to three effective temperature zones: at or below T1, between T1 and T2, and at or above T2; however, it should be recognized that the method and system may contain more or fewer zones, and various heating and charging actions may be modified accordingly. For example, an intermediate zone may be divided into sub-zones, where the system transitions between effectively performing more heating and effectively performing less heating, and from effectively performing less charging to effectively performing more charging, as the system generally transitions from a first state in which the system only heats to a third state in which the system only charges. Regardless of whether the intermediate zone or state is divided into sub-zones, in the intermediate stage, the system can charge at a lower rate than in the final stage where the battery has risen to a temperature where charging can continue without additional heating. In any case, in a particular instance, the system determines which mode to initiate from the battery's acquired temperature T, i.e., heating, mixed heating and charging, or charging (operation 802).

[0074] In the first mode (operation 904), when the temperature is too low to charge (e.g., when T is at or below T1), the system accesses a signal solely for heating. Reference Figures 4 to 6 Examples of such signals will be discussed as examples, and examples of such signals can be, for example... Figures 1 to 3 The circuit shown is provided. In one particular embodiment, the heating signal is a sinusoidal current waveform, such as... Figure 4The current waveform is generally shown in the diagram. Centered on zero current, it features alternating sinusoidal positive currents 410 and negative currents 420. The frequency of the sine wave can be selected based on the battery type and through battery characterization and testing. When the temperature is considered too low to charge without potentially damaging the cell, one goal of an alternating heating waveform in the form of a sinusoidal curve centered on zero current or other shapes is to heat the battery first without generating any meaningful net charge, as well as other matters discussed above.

[0075] The method is described as follows: starting in a first mode (operation 804), checking the temperature, and based on the battery temperature, proceeding to a second mode, and then to a third mode. It should be recognized that the method may begin first in either the second or third mode, depending on the initial temperature. Additionally, in some arrangements, the heating sequence may begin for a period of time, unlike when the battery reaches a certain temperature (e.g., T1 or T2). Thus, for example, if the initial temperature is below T1, the system may begin the heating sequence for a period of time and then transition to the hybrid mode two discussed below, or, in embodiments without intermediate modes or where timing should be set to avoid involving intermediate modes, simply bypass the hybrid mode and move to the fully charged mode three. It should be noted that other thresholds besides battery temperature (e.g., applied time or current, time at ambient temperature, modeling, and combinations thereof) are also possible. Similarly, while the method is primarily discussed relative to reaching different threshold temperatures T1 and T2, the system may operate upon reaching these temperatures, at a certain range near these temperatures, and in other cases.

[0076] It should be recognized that other heating signals can also be used in the first mode. In the case where the charging sequence is initiated first when the temperature is below T1, and therefore the heating mode is initiated first, the sine curve centered at zero can be transformed into a sine curve with a certain positive DC offset, depending on the temperature, such that a certain charge begins or starts at a sine curve with a certain positive DC offset or other greater positive charge energy, for example, in... Figure 5 The signal then transitions to the second mode, as discussed below, when temperature T1 is reached and the battery temperature exceeds T1 or even exceeds the second temperature at which the system transitions to a full charge sequence.

[0077] continue Figure 8 For example, when temperature T1 is reached, the system can switch to a second mode. In the second mode, when the battery temperature falls within a certain range (e.g., T between temperature T1 and temperature T2), the system can use a hybrid charging signal, an example of which is shown in... Figure 9A and Figure 9BThe mixed charging signal may include charging portions 902, 904 and heating portions 906, 908. The example illustrates a repeating pattern where charging portions are followed by heating portions. However, the mixed signal may contain any sequence of charging and heating portions. For example, the mixed charging signal may contain a sequence of a number of charging portions (e.g., 902 or 904) followed by heating portions (e.g., 906 or 908), and then a subsequent sequence of heating portions. In this example, each charging portion begins at the end of the current charging portion. Similarly, the duration of the charging and heating portions may vary. For example, near temperature T1, the heating portions may be relatively longer than the charging portions compared to near temperature T2, at which temperature T2 the charging portions may be relatively longer than the heating portions (or a series of charging portions (which may include intervention pauses) occur before the heating portions), or some heating portions may be replaced by pauses as discussed below and elsewhere herein. Figure 9A and Figure 9B In this example, the pause cycle would involve a transition from charging section 914 (916) to 918 (920) to a pause cycle with no charging or discharging current (or substantially no charging or discharging current), said pause cycle occurring at the location showing heating section 906 or 908, and subsequently transitioning to another charging section 902 or 904. Similarly, the mixed signal may contain less relative charge energy near temperature T1 and more relative charge energy near temperature T2. Similarly, the mixed signal may change dynamically or programmatically as the temperature increases between temperatures T1 and T2. Similarly, the signal definition may be controlled by the starting temperature (e.g., whether the starting temperature falls at a certain location within the range of T1 to T2).

[0078] In the illustrated example, the charging portions 902, 904 of the mixed charging and heating signals comprise sinusoidally shaped or otherwise more generally shaped non-abrupt leading edges 910, 912 followed by body portions 914, 916, which terminate at falling edges 918, 920. In many examples, the leading edges (e.g., leading edges 910 or 912) may not be immediate, extremely high-frequency edges, for example, in a square wave, to avoid injecting high-frequency harmonics into the battery at the start of the charging portion of the signal. Reference Figure 9A The heating section 906 falls between the charging sections and is defined by a sinusoidal heating signal centered at approximately zero amperes. Therefore, the sinusoidal curve oscillates between positive (charging) current and negative (discharging) current. In some instances, the heating signal provides approximately zero net capacity difference, where the energy during the heating section of the mixed signal is primarily used for heating, with little or no net energy used for charging or discharging the cell. Figure 9B The heating portion of the charging signal discussed in the paper has a certain DC offset, which will be discussed in more detail below.

[0079] In various possible instances, the frequency range of the sinusoidal heating portion of the mixed signal or the heating signal alone (discussed previously) can be from 1 kHz to 100 kHz. Depending on the cell and specific conditions, the frequency range can also be reduced to below 1 kHz, for example, in the range of 100 Hz to 1 kHz. Similarly, in some cases, frequencies above 100 kHz are possible. In a specific example of a 3000mAh lithium-ion rechargeable cell, where the specified maximum discharge current is 35 A and the specified current for conventional CCCV charging at 4.2 V is 4 A, the heating sinusoid can be 10 kHz and cycle between -10 A and 10 A (in the case of this cell, temperature T1 can be approximately -10°C, and the cell temperature can reach 5°C at T2). The heating described in such an example and other examples herein causes the maximum possible internal heat resulting from contributions by the resistance and susceptance mechanisms. The susceptance caused by the coiled electrodes generates a magnetic field, which is absorbed by the magnetic element in the cathode, thereby allowing the magnetic element to interact with the current through the current collector. 2 The heating current participates in heat generation in parallel with the heating process. It should be recognized that this relatively high current is typically specified at relatively low temperatures. For example, for the same type of cell, a conventional charge (if permissible) would be approximately 2 A. However, as mentioned above, the energy of the heating portion of the signal is primarily used for heating, thus allowing for a higher current than when charging alone. The frequency of the heating signal, as well as the positive and negative current values, will vary depending on the type of battery, the capability of the charging circuitry, the power supply capacity, and other factors. While the heating sinusoidal signal can be symmetrically positive and negative (e.g., cycling between +10 A and -10 A), it is also possible to have an asymmetrical signal. The sine curve can also be centered at a positive DC offset (e.g., ...). Figure 9B (As shown in the diagram), this allows for the presence of some net charge during the heating phase, or a transition from a zero-centered sine curve to a non-zero positive-offset sine curve as the battery heats up through the temperature range between T1 and T2. Mode two can also be operated within a set time period, or modes one and two can be operated sequentially and in combination within a set time period, with the transition from the first mode to the second mode based on time. In addition to time and temperature, other thresholds can be used to transition between signals, such as ambient temperature, net current to the battery, or using other measurements such as voltage as a representation of temperature.

[0080] In the third mode (operation 808), when the battery temperature T is at a temperature T2 sufficient for charging without additional heating, the system switches to a charging sequence. In various aspects, and primarily referring to... Figure 10AThe charging signal 1000 includes a shaped leading edge 1010, a body portion 1020, and a rest portion 1030. In a mixed signal or charging signal, the shape of the leading edge may be that of a sine wave at a frequency selected based on a relatively low impedance harmonic frequency. The sinusoidal leading edge is followed by a relatively stable charging current (e.g., the body portion 1020), which terminates at a falling edge. Unlike a mixed signal, the falling edge is not followed by a sinusoidal heating portion, but rather by a rest period 1030. The rest period may be zero current, or it may be a non-zero DC current less than the current of the body portion (see, for example...). Figure 10B Depending on the cell type, the peak current of the main body can range from 10 A to 60 A, and the rest current from 0 A to 10 A. Peak current, rest current, and other values ​​can vary depending on temperature, cell type, circuit capacity, state of charge, and other factors, as mentioned elsewhere in this document. In this example, if the rest current is non-zero, it can be less than the specified charging current when using conventional CCCV charging. For example, if the charging current using CCCV charging is approximately 4 A at 4.2 V, the rest current can be 2 A or less.

[0081] In some instances, a heating signal can be applied to maintain the battery within certain operational ranges. This signal can be applied when the battery temperature drops below a certain temperature threshold, or even when the battery is fully charged. Because the frequency can be selected without net charge being applied to the battery, heating can be maintained without exceeding an upper charge threshold. Alternatively or additionally, the system can charge and discharge the battery within a small window (e.g., 99%-100%) while simultaneously generating a heating signal to maintain the battery temperature. In various instances, when connected to a charger, the system can maintain the battery temperature within the range optimal for powering a given load and prevent the battery from dropping below an operational threshold in cold environments that could otherwise cool the battery below or otherwise push it into suboptimal operating temperature ranges.

[0082] Regarding various modes and other methods, you can use... Figures 1 to 3 The circuits and other methods described herein are used to generate various heating signals, mixed charging and heating signals, and charging signals.

[0083] As mentioned herein, the charging signal, or a hybrid charging and heating signal, may include a shaping leading edge, a main body, and a rest period. It should be noted that the rest period may also include a heating sinusoidal superposition. The described charging technique and charging signal are not conventional constant-current constant-voltage charging, in which, essentially, a predetermined constant charging current is applied until the battery voltage begins to rise, at which point the charging current decreases. The charging technique is also not pulse charging, because the charging signal defines a specific shaping leading edge; in fact, the high-frequency harmonic content of square pulses is generally avoided for charging, especially when the pulse is first initiated, at least due to the high impedance to the uncontrolled high-frequency harmonic content of square pulses.

[0084] refer to Figure 11 A method for shaping the charging portion of a signal (e.g., a mixed charging and heating signal or a charging signal) involves obtaining the impedance spectrum of the battery, selecting a frequency where the impedance is relatively low based on the impedance spectrum, and using said frequency to define the shaped leading edge of the charging portion of the signal. In one example, the system uses or otherwise references a value of the imaginary impedance (reactance). The shaped leading edge and the overall signal can be used... Figures 1 to 3 It is generated by the circuits described in the text.

[0085] To obtain the impedance spectrum, in one possible instance, the method involves applying a probe signal to the battery (operation 1102). The probe signal may contain a harmonic spectrum, which can be used by the system to evaluate the battery's impedance to various harmonics. The probe signal may be a charging signal or a dedicated signal. The probe signal may be interleaved during charging, or may operate discontinuously at the start of charging, intermittently or periodically during charging, or otherwise. In one instance, the probe signal may be a square wave or a square pulse. In a particular instance, the probe signal is a square wave centered at zero amperes. In one possible instance, the probe signal is a square wave centered at zero amperes with a +4 V (positive) portion and a -4 V (negative) portion. Here, the average current is 0 A. The duty cycle is 50%. The frequency, duty cycle, current or voltage magnitude, or other properties of the probe signal may vary depending on the cell type, device type, temperature, state of charge, and other possible parameters. These parameters can be determined based on the characterization of any given cell type. In a specific example, a square wave probe is applied to the battery for a single cycle of approximately 30 milliseconds. In other words, the probe signal can include a square pulse of a given current and a negative square pulse of a given current. The pulses can have the same duration, for example, 15 milliseconds each, or they can have different durations. The probe signal can be only positive pulses (current to the battery) or only negative pulses (discharge current from the battery). Each pulse can contain the same amount of current, or the pulses can be asymmetrical. While other probe signals are possible, square pulses or square waves have harmonic content over a wide frequency range and are efficiently generated by conventional charging hardware topologies. Generally, the purpose of the probe signal is to introduce a wide spectrum of harmonic content into the battery in a very simple and discrete way to assess the battery's impedance to various harmonics. Therefore, whether it is a square wave, a square pulse, or any other signal, the probe signal aims to briefly introduce the harmonic spectrum into the battery. In the case of a square wave centered at zero amperes, there can also be equal amounts of current flowing into and out of the battery, with little or no net charge effect. The idea is to probe the cell without changing its state of charge. Where changing the State of Charge (SOC) is similarly acceptable—for example, at an SOC less than 100% and within a suitable charging temperature range—a certain net charge is possible and acceptable. Similarly, a negligible net charge from the probe signal is acceptable when probing is infrequent and the net charge is therefore negligible. In some arrangements, a series of different probes containing varying harmonic content can be injected. Although uncontrolled and / or high-frequency harmonics can have detrimental effects on the battery, for the purpose of obtaining the impedance spectrum, the system applies a square pulse for only a very short duration, thus substantially avoiding such effects.

[0086] In the presence of a probe signal, the system measures the current and voltage at the battery terminals (operation 1104). The current and voltage signals are captured in the time domain. For each of the current and voltage measured in the presence of a probe signal, the system obtains a spectrum, from which it can further generate an impedance spectrum (operation 1106). In one example, the system generates a domain transform of the current and voltage signals to produce a voltage spectrum and a current spectrum. The domain transform can be a discrete wavelet transform using Morlet wavelets. In some examples, the wavelet can also be considered a Gabor wavelet or a complex Morlet wavelet. In one possible implementation, the system can use fixed-point arithmetic to generate the impedance spectrum, which allows for the use of relatively low-cost and simpler microcontrollers or other computing platforms in some more typical charging environments where significant computing power would otherwise be unnecessary or conventionally available.

[0087] The system generates an impedance spectrum from the spectra of current and voltage signals (operation 1106). In one instance, the impedance spectrum is generated by dividing the voltage spectrum by the current spectrum. More specifically, the impedance at various frequencies is generated by dividing the complex voltage values ​​at the same frequency by the complex current values ​​at the same frequency. This produces a complex impedance spectrum. In some instances, it is sufficient to limit the generation of the impedance spectrum to a discrete frequency range (e.g., 200 Hz to 3 kHz).

[0088] Regardless of the technique used, the system generates an impedance spectrum that identifies the battery's impedance to harmonics of a specific frequency of a signal applied to it. Therefore, in a simplified example, multiple harmonics will be present in the square pulse probe signal applied to the battery. Using the techniques discussed herein, the system generates discrete impedances of the battery to some or all of the discrete harmonics in the probe signal. The spectrum, broadly speaking, represents the battery's resistance to a charging signal at a specific frequency. The battery may have more or less impedance (more typically resistance) to different frequency harmonics of the probe signal.

[0089] Based on the impedance spectrum, the system can identify specific harmonics used to define the leading edge of the charging portion of the signal (operation 1108). To determine the shape of the leading edge of the charging signal, the system determines an optimal frequency based on the impedance spectrum generated from the probe signal. In a particular instance, the optimal frequency is the frequency associated with the lowest impedance (specifically, in some embodiments, reactance) in the impedance spectrum. Therefore, the system selects the frequency associated with the lowest impedance. It should be understood that there may be examples where the system can actually evaluate admittance (e.g., the highest admittance or the imaginary part of the admittance – susceptance). Generally, a charging signal applied to the battery with a shape having a frequency associated with a lower impedance will transfer energy for charging more efficiently than a frequency associated with a higher impedance. Subsequently, the optimal frequency is set as the leading edge of the charging signal or the charging portion of the mixed signal. Therefore, the leading edge 1010 defines a portion of a sine curve at the identified frequency, such as... Figure 10A and Figure 10B As shown in the examples.

[0090] In addition to the shape of the leading edge of the charging section, the system also determines the overall properties of the signal, the overall signal period, and other properties, including the duration of the rest period relative to the charging time (including the shaped section and the main body). In one possible instance, the period and rest period of the charging signal are preset and based on battery characterization. The period of the charging signal includes the shaped leading edge and the main body following it. In various possible instances, the charging section can fall within the range of hundreds of microseconds to tens of milliseconds. The entire period includes the charging section and the rest period (or heating section). The rest period (or heating section) can fall within the range of hundreds of microseconds to tens of milliseconds. In other possible instances, the period can fall within the range of hundreds of microseconds to tens of milliseconds. The peak current at the peak of the shaped leading edge and the main body of the charging section of the cell can be approximately 20 A, but the peak current value depends on the cell type, temperature, characteristics, and other factors, and therefore can differ significantly from the example peak current. An example of determining the charging current (including the peak current) is discussed below.

[0091] The method for determining the shape of the leading edge can be repeated periodically, intermittently, at the attainment of various targets (SOC or others), or otherwise throughout the heating or charging cycle. In a particular instance, at approximately every The detection signal and subsequent operation are repeated with a 1% change in SOC (1104-1110). In another example, the detection signal and subsequent operation are performed over time (e.g., every 5 seconds, every 30 seconds, or every 60 seconds). The frequency of the detection signal and subsequent operation can vary over time. For example, as the cell heats up, the cell can change more rapidly, and therefore the detection rate, etc., can change. The detection rate can also change as the cell approaches full charge.

[0092] Various aspects of this disclosure also relate to a method for generating a current level for a charging signal, wherein the current level is set such that the battery does not overheat during a charging cycle. The method can be used in conjunction with the techniques described herein, for example, by setting the current level of a shaped hybrid charging and heating signal or a shaped charging signal. The method can also be used to set the current level of any form of charging signal to address battery heating that occurs during charging in many different charging scenarios, and to prevent the battery from overheating during charging, as well as other advantages, individually or in combination.

[0093] First, refer to Figure 12 Method 1200 begins by accessing the battery temperature and ambient temperature (operation 1202). The technique may take into account both battery temperature and ambient temperature, battery temperature alone, or other parameters. As mentioned herein, the battery temperature can be obtained or accessed in many possible ways. The ambient temperature may be obtained from a temperature sensor positioned to detect the ambient temperature in the environment containing the battery to be charged. The ambient temperature may also be accessed from a third-party device (e.g., a temperature sensor in proximity to the device to be charged) and provided by means of a signal such as Bluetooth or WiFi. In some arrangements, the ambient temperature may be obtained by means of a network connection, for example, from a third-party service accessible via a network connection. In any case, the system may access one or both of the battery temperature and the ambient temperature. The system may also access an estimate of the ambient temperature over time.

[0094] The system then uses the battery temperature and ambient temperature to determine the maximum current used for charging the battery (operation 1204). The maximum current is the current at which the battery will remain below a maximum threshold temperature during charging when charged at or below the maximum current. The maximum threshold temperature may be, for example, a specified maximum temperature above which charging is interrupted. The maximum threshold temperature may also be some other specified maximum temperature that the system attempts not to exceed.

[0095] The maximum current takes into account the state of charge and identifies the charging current that, when applied to the battery, will not cause the battery to heat up to a temperature above the maximum threshold temperature at the end of a charging cycle. Therefore, for example, at the same temperature, the maximum current at a relatively high initial state of charge can be higher than the relatively lower maximum current at a lower initial state of charge.

[0096] In one instance, the system accesses a model, which may be in the form of an equation (e.g., a quadratic equation containing variables of battery temperature and ambient temperature). The model may also be a lookup table that receives battery temperature and ambient temperature values ​​as keys and identifies charging current values ​​based on those keys. In another instance, the model may be based on battery characterization, identifying a temperature characteristic curve of the battery across a spectrum of charging conditions and how those charging conditions affect the battery temperature.

[0097] In response to battery temperature and ambient temperature, the model generates a maximum charging current. In one example, the model may assume a fully discharged state, and the identified charging current value represents the current at which the battery can be charged to a fully charged state without exceeding a maximum threshold temperature. The system may also accept a state of charge and generate a current count to achieve full charge without exceeding the threshold temperature. In this example, the current value may be slightly greater than the current value that would come from a fully discharged state. One advantage of the technique of not considering the state of charge is that the system can operate in a manner that assumes the current will not exceed the temperature threshold and does not require access to an accurate ongoing state of charge assessment. This can be beneficial in various situations, such as when the battery is being charged for the first time and the current or accurate SOC is not available.

[0098] The system uses ambient temperature to account for the battery's environment and its impact on battery heating. In one example, a maximum current is set at the beginning of a charging cycle and is not updated during the cycle. In another example, the system may update the maximum current value based on time, the progress of the charging state, changes in ambient or battery temperature, and other measurements. In yet another example, the maximum current value may be one of other values ​​used to determine the charging current at any given point in the charging sequence.

[0099] It should be noted that the maximum current or any other current value may be limited by the capabilities of the charging environment. Therefore, the system may also access current limit values ​​based on the charging environment (operation 1206). In some examples, the charging hardware itself may be limited in terms of the amount of charging current it can supply. For example, the system may be able to charge from a higher current source but connected to a lower current source that limits the maximum charging current the system can provide. In other examples, other limitations may be imposed on the system indicating the current limit available for charging the battery. For example, the charging hardware may be limited based on the limitations of the power source. Regardless, the system may consider current limits based on the system. If the maximum current from operation 1204 exceeds the system current limit, this becomes relevant, and the system current limit effectively becomes the maximum current.

[0100] Finally, the system can access a third current parameter associated with the amount of (e.g., maximum) charging current to the battery based on its current temperature (operation 1208). As mentioned herein, batteries below or within a certain temperature threshold cannot be charged at the same rate as when above or within a threshold range. As the battery heats up, a higher charging current becomes available. Any given battery type can be characterized by identifying the maximum charging current that can be applied without damaging the battery based on its temperature. As mentioned herein, temperature plays a role in the battery's ability to receive charge. In this example, the system accesses a model that determines the maximum current at the current time based on the current battery temperature. In the case of identifying the maximum current that can be applied to maintain the battery at or below a certain threshold in the future (e.g., when the battery reaches a fully charged state), as discussed above, the model in this example identifies the maximum charging current that the battery can accept at the current time based on its current temperature. This value can change as the battery heats up. Additionally, if the value is below the threshold (e.g., T < T1 discussed above), the model will indicate that charging current should not be applied until the battery reaches or exceeds the threshold.

[0101] Therefore, in summary and in one instance, the system can identify three maximum current limits: (1) a first current limit, which is the maximum current taking into account the battery temperature and the ambient temperature, under which the battery is chargeable and will not exceed a certain temperature in the future; (2) the maximum current that the system can support; and (3) the maximum charging current that can be applied to the battery based on the current temperature of the battery.

[0102] The system then selects the minimum of the three generated current limits. Therefore, for example, at relatively low battery temperatures and in cold environments, the first current limit may be relatively higher than the third current limit because the battery is initially cooled and cannot accept maximum charging, and the relatively cold ambient environment prevents the battery temperature from rising as it would in a relatively warmer environment. Therefore, the system selects the third current limit because charging at the relatively high first current limit would exceed the third current limit. However, as the battery warms up, the third current limit value may rise above the level of the first value; in this case, the system will select the first current limit instead of the third current limit. In this way, the system can instantaneously charge at a higher rate but will not select a current that would cause the battery to overheat later in the charging cycle. If, in any case, the maximum current from the system is less than either or both of the first and third limits, the system will use the second current limit because the system cannot provide a higher first or third limit.

[0103] As mentioned above, in a hybrid heating / charging mode or a charging-only mode, the system applies a complex shaped charging signal with a charging portion and a heating portion or a rest portion, where either or both of the heating or rest portions may contain a positive offset, such that a certain charging current is transmitted during the heating or charging portion. The maximum charging current value can be converted into the various portions of the complex charging signal.

[0104] In a specific instance, the maximum charging current is the average value of the total complex charging signal (operation 1212). The system sets the peak current of the charging portion of the signal based on the average value (maximum charging current) and other parameters of the charging signal, such as the overall period and rest period of the charging and resting portions of the signal, the duty cycle, or a combination thereof. As mentioned above, when determining the shape of the charging portion, the system can access the time parameters of the overall signal, such as the overall period and rest period. Using this information, the system can determine the time of the charging portion of the signal (the shaped portion and the main body).

[0105] In one possible example, the system uses a current limit (average current) to set the peak current of the main body of the signal, while also taking into account charge transfer that occurs during the shaping front. For comparison purposes, if the system selects an extremely high-frequency harmonic for the shaping front (which will appear as a regular square wave), and the system determines a 50% duty cycle (50% for the charging section plus the main body and 50% for the rest section), where the current limit is set to 5 A, the peak current of the charging section will be 10 A. However, for a mixed charging and heating signal or a charging signal, the system will generate relatively low-frequency harmonics because such charging energy is transferred during the shaping front (not the high-frequency sharp front of a square wave) and during the charging main body. In the same example with a 50% duty cycle, if the average current is set to 5 A, the peak current at the upper portion of the shaping front and the main body will be greater than 10 A because a certain amount of charge is transferred during the shaping front of the charging section, with the remaining charge transferred during the charging main body. In this example, the system considers both the shaping leading edge and the body within 50%, and therefore the peak current of the body is higher than 10 A because less energy is transferred during the shaping leading edge portion compared to a conventional square pulse. Therefore, when determining the peak current, the system considers the charge transferred during both the shaping and body portions of the signal's charging phase.

[0106] In almost all cases, the peak current will be greater than the maximum current selected from operations 1204-1209. In some cases, the system may determine a peak current greater than that that can be supplied by the system's hardware. In such cases, the system may generate a positive charging current offset during the rest period, such that the average current is reached over the entire cycle of the signal (charging and resting portions). In other cases, the system may adjust the overall cycle so that the rest period remains the same, but the charging portion is increased, such that the average current is reached over a signal cycle by extending the time during which the charging signal portion positively delivers charging current. In yet another instance, the system may maintain the same overall cycle while shortening the rest period.

[0107] According to various aspects of this disclosure, the system may involve a controlled discharge signal from a battery, whether as part of a heating sequence or for powering a load, said controlled discharge signal containing a variety of possible harmonics (e.g., harmonic components at a specified frequency or otherwise shaped discharge signals). See again Figure 1-3 as well as Figure 13 The system may include a battery 104 (1304) and a controller 100 (1300), which manages the battery's discharge signal individually or in combination with a charging signal when in a heating context, but may use discharge control for optimal battery discharge during normal operation of a battery-powered system. The controller may be a processing unit of some form and may be part of a control system separate from the battery, or may be integrated with the battery in a battery management system. Regardless of the control configuration, the entire system provides a discharge signal, wherein one or more of the signal's leading edge, other aspects of the signal's edge, harmonics including the body of the signal, and / or the signal's trailing edge can be tuned to a specific frequency. This may be attributed to reducing and / or minimizing the battery's impedance properties in the presence of a discharge signal during system operation, or in various possible instances otherwise tailored to initially heat the battery so that it can be switched to charging a load or otherwise supplying power. In any case, the harmonic components of the discharge signal are controlled, or more generally, the discharge signal has unconventional non-DC properties. One or more harmonic components can be selected and controlled based on an assessment of complex impedance or other battery properties in the presence of discharge harmonics. These harmonic components reduce or otherwise minimize impedance properties (e.g., complex impedance) when supplying power to a load in the presence of a discharge signal, or generate harmonics with relatively high impedance such that energy is primarily consumed as heat when in heating operation mode, or control other harmonic properties for various possible reasons. Controlling discharge in these ways offers several potential advantages for the battery, including optimized heat during discharge, enhanced battery life and capacity, increased discharge current, and other advantages compared to discharging the same type of battery using conventional techniques.

[0108] However, in such harmonic-controlled discharge signal environments, conventional downstream systems may not be suitable for receiving such harmonic-controlled signals from the battery. Therefore, in one example, the discharge signal conditioning element 1302 is positioned between the battery 1304 and the load 1306 (144), or integrated within the load. The discharge signal conditioning element is used to condition unconventional discharge signals suitable for the load or for components that power the load using energy from the battery. In one example, and referring to… Figure 1 The discharge signal conditioning element is a suitable capacitor 122 or capacitor bank, or other energy storage element, which is positioned to receive a discharge signal from the battery and store sufficient energy to meet the load's needs. In one example, the load system 1306 may also include a DC-to-AC converter or other form of power conversion element 146. Figure 1 This system supplies power to the load, and a capacitor or capacitor bank is positioned between the battery and the DC-to-AC converter assembly of the load system. Subsequently, a harmonic-controlled discharge signal is used to charge the capacitor bank, which directly provides the DC source required by the DC-to-AC converter or the load. The size and arrangement of the capacitor bank are designed according to the power requirements of the load.

[0109] In another example, the load is configured to receive a harmonic-tuned discharge signal from the battery. For a DC-driven load, such as and similar to the embodiments discussed above, the load may include a capacitor 122 at the input of the load, which removes harmonic content from the discharge signal. In other examples, the discharge signal can be controlled by a buck or boost circuit driving the load. In such examples, the buck or boost circuit can be controlled to customize the harmonic content of the discharge signal and simultaneously tuned to the discharge signal of the load. Although the signal conditioning element and the load system are shown as separate blocks, signal conditioning can be integrated with the load system.

[0110] In some examples, the heating waveform, particularly a sinusoidal heating waveform, can be set as a frequency based on a combination of the real and imaginary components of impedance, or a frequency property containing a combination of the real and imaginary components of impedance. Specifically, with respect to admittance, the heating waveform frequency can be based on the real admittance (conductance) response and the imaginary admittance (susceptance) response. This discussion is set forth in the context of admittance (specifically, conductance and susceptance), but it should be understood that it can also be applied to resistance (the reciprocal of conductance) and reactance (the reciprocal of susceptance).

[0111] Figure 14A This is a graph showing the real admittance (conductance) response of a sinusoidal signal applied to an example lithium-ion cell at a 50% charge state on the frequency spectrum. (See figure.) Figure 14AAs shown in the figure, at frequency A and towards frequency B, the conductance changes from a relatively high first conductance value at frequency A to a relatively low second conductance value at frequency B, where the conductance continues to decrease at frequencies above frequency B. In the figure shown, frequency A is located at the inflection point 1402 in the conductance response curve, where the conductance increases with frequency up to frequency A, and then begins to decrease at frequencies above A. In the example shown, the conductance at frequency A is also at a local maximum.

[0112] refer to Figure 14B As can be seen, at approximately frequency A, as the frequency increases to frequency B, for the same representative lithium-ion cell at 50% SOC, the susceptance changes from a relatively low initial susceptance value to a local maximum peak susceptance value at frequency B. In the figure shown, frequency B is located at the inflection point 1402 in the susceptance response, where the susceptance increases with frequency up to frequency B, and then begins to decrease at frequencies above frequency B.

[0113] In various possible instances, the sinusoidal frequency of the heating signal discussed in the various embodiments above can be established based on the conductance response, the susceptance response, or a combination of both. As mentioned, the discussion also applies to identifying the admittance of the reciprocals of resistance and reactance.

[0114] In one possible example, the heating frequency can be set to a value between the frequency at which conductance peaks (e.g., the frequency at A) and the frequency at which susceptance peaks (e.g., frequency B). In another example, the heating frequency can be set to a value between the inflection point frequency of the battery's conductance response and the inflection point frequency of the battery's susceptance response. In the frequency region between A and B, conductance decreases relatively steeply, and susceptance increases relatively steeply. The heating frequency can be selected from a value within the frequency region between A and B.

[0115] In more specific instances, the frequency of the heating signal is in the range near the midpoint between frequencies A and B (e.g., frequency X). Reference Figure 14A and Figure 14B In about 10 3 The conductivity peaks at Hz and is around 10 Hz. 4 The susceptance peaks at Hz. In this specific reference, it can be seen that the conductance peak is located below 10 Hz. 3 At a frequency of Hz, and the peak susceptance is less than 10 Hz. 4 At frequencies of Hz, the term approximately refers to the fact that the precise scale of the graph is not at a granular level to specify an exact frequency, and the graph is actually used to illustrate general conductance and susceptance curve characteristics. However, in this example, the heating frequency is chosen as frequency X, which is approximately midway between frequency A and frequency B.

[0116] From an electrochemical and electrodynamic perspective, at frequency A, electrons can travel a greater total distance within the charged cell, making it easier to counteract the charge from the applied electric field. Therefore, and because other materials in the cell do not exhibit polarization, the cell cannot support the high susceptance required for more uniform and multi-component charge propagation and electron mobility. At frequency B, susceptance and polarization are at their maximum, but electron mobility is significantly reduced, thus decreasing If from the current collector. 2 Heating of R. At frequencies between A and B, for example, at X, conductivity and I. 2 The heating R remains high, while the susceptance is much higher than that at frequency "A," indicating that additional components and electrode regions are involved in heat generation. It is well known that the susceptance arises from the coiling of the electrodes in a cylindrical cell, and therefore, it can be assumed to be relatively uniform throughout the cell. The frequencies within the selected range can also be sufficiently removed from the time constants associated with chemical, electrochemical, and possibly electrodynamic mechanisms, thus avoiding nucleation and SEI growth during heating.

[0117] The frequency range between the local maxima (inflection points) of conductance and susceptance is defined as a region of frequencies that can be selected to balance these problems and advantages. The frequency range can also be based on conductance or susceptance alone. For example, when identifying a local maxima at a conductance inflection point, frequencies within a certain range of frequencies at the inflection point can be selected. In a more detailed example, the frequency can be greater than the frequency at the inflection point. The degree to which the frequency is greater can be set to a fixed offset, based on a difference (e.g., percentage) below the conductance value at the inflection point. Regarding susceptance, when identifying a local maxima at a susceptance inflection point, frequencies within a certain range of frequencies at the inflection point can be selected. In a more detailed example, the frequency can be less than the frequency at the inflection point. The degree to which the frequency is less than the inflection point can be set to a fixed offset, based on a difference (e.g., percentage) below the susceptance value at the inflection point. Regarding conductance or susceptance, the heating frequency can also be selected based on a local minimum of conductance or susceptance, wherein a frequency less than the selected local minimum of conductance or greater than the selected local minimum of susceptance is selected. Figure 14A and Figure 14B In the frequency range, the local minimum of susceptance is similar to (slightly less than) the local maximum of conductance at 1402.

[0118] The term “about” will be understood by those skilled in the art and will vary to some extent depending on the context in which it is used. As used herein, when referring to values ​​such as frequency, temperature, current, etc., the term “about” means to cover variations of ±10% from the specified value, including variations of ±5%, ±1%, and ±0.1%, as such variations are suitable for performing the disclosed methods.

[0119] In all of the above examples, including Figure 14A and Figure 14B The discussion suggests that heating frequencies can be selected based on various criteria. In some instances, the frequency is based on an inflection point, a midpoint, or some other criterion, and it should be recognized that there is a degree of flexibility regarding the precise number chosen. Thus, for example, a frequency referencing an inflection point may be located at or approximately at the inflection point, meaning it can be within 10% of the value, or within other percentage values ​​mentioned above. Similarly, if at the midpoint between frequencies, the value can be within 10% of the midpoint to either side.

[0120] refer to Figure 15 This document provides a detailed description of an example computing system 1300 having one or more computing units capable of implementing the various systems and methods discussed herein. The computing system 1500 may be part of a controller, operatively communicable to the various embodiments discussed herein, capable of performing various operations related to the methods discussed herein, capable of operating offline to process various data for characterizing a battery, and may be part of the overall system discussed herein. The computing system 1500 may process and / or provide the various signals discussed herein. For example, battery measurement information may be provided to such a computing system 1500. The computing system 1500 may also be adapted, for example, to controllers, models, tuning / shaping circuits discussed relative to the figures, and may be used to implement the various methods described herein. It should be understood that specific embodiments of these devices may be different possible specific computing architectures, all of which are not specifically discussed herein but will be understood by those skilled in the art. It should be further understood that a computer system may be considered and / or comprise an ASIC, FPGA, microcontroller, or other computing arrangement. In these various possible implementations, more or fewer of the components discussed below may be included, with interconnections and other changes that will be understood by those skilled in the art.

[0121] Computer system 1500 may be a computing system capable of executing computer program products to perform computer processes. Data and program files may be input into computer system 1500, which reads the files and executes the programs therein. Figure 15 The diagram illustrates some of the components of a computer system 1500, including one or more hardware processors 1502, one or more data storage devices 1504, one or more memory devices 1506, and / or one or more ports 1508-1512. Additionally, other components that those skilled in the art will recognize may be included in the computing system 1500, but are not shown in the diagram. Figure 15 The various components of the computer system 1500 are explicitly described or further discussed herein. They can be communicated via one or more communication buses, point-to-point communication paths, or... Figure 15Other communication components not explicitly depicted communicate with each other. Similarly, in various embodiments, the various elements disclosed in the system may or may not be included in any given embodiment.

[0122] Processor 1502 may include, for example, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), and / or one or more internal levels of cache. One or more processors 1502 may exist, such that processor 1502 includes a single central processing unit, or multiple processing units capable of executing instructions and performing operations in parallel with each other, which is generally referred to as a parallel processing environment.

[0123] The techniques described herein, in various possible combinations, can be implemented at least in part in software stored on data storage device 1504, stored on memory device 1506, and / or transmitted via one or more of ports 1508-1512, thereby enabling Figure 15 The computer system 1500 in the document is transformed into a dedicated machine for performing the operations described herein.

[0124] One or more data storage devices 1504 may include any non-volatile data storage device capable of storing data generated or used within the computing system 1500, such as computer-executable instructions for performing computer processes, which may include instructions for both application programs and an operating system (OS) for managing various components of the computing system 1500. Data storage device 1504 may include, but is not limited to, disk drives, optical disc drives, solid-state drives (SSDs), flash drives, etc. Data storage device 1504 may include removable data storage media, non-removable data storage media, and / or external storage devices available via wired or wireless network architectures having such computer program products, which include one or more database management products, network server products, application server products, and / or other additional software components. Examples of removable data storage media include compressed optical disc read-only memories (CD-ROMs), digital versatile optical disc read-only memories (DVD-ROMs), flash drives, etc. Examples of non-removable data storage media include internal magnetic hard drives, SSDs, etc. One or more memory devices 1506 may include volatile memory (e.g., dynamic random access memory (DRAM), static random access memory (SRAM), etc.) and / or non-volatile memory (e.g., read-only memory (ROM), flash memory, etc.).

[0125] A computer program product containing mechanisms for implementing systems and methods according to the presently described technology may reside in data storage device 1504 and / or memory device 1506, which may be referred to as a machine-readable medium. It should be understood that a machine-readable medium may comprise any tangible non-transitory medium capable of storing or encoding instructions to perform any one or more operations of this disclosure executed by a machine, or any tangible non-transitory medium capable of storing or encoding data structures and / or modules utilized by or associated with such instructions. A machine-readable medium may comprise a single medium or multiple media (e.g., a centralized or distributed database and / or associated caches and servers) storing one or more executable instructions or data structures.

[0126] In some embodiments, computer system 1500 includes one or more ports for communicating with other computing, network, or vehicle devices, such as input / output (I / O) port 1508, communication port 1510, and subsystem port 1512. It should be understood that ports 1508-1512 can be combined or separated, and computer system 1500 may contain more or fewer ports. I / O port 1508 can be connected to I / O devices or other devices through which information is input to or output from computing system 1500. Such I / O devices may include, but are not limited to, one or more input devices, output devices, and / or environmental transducer devices.

[0127] In one implementation, the input device converts human-generated signals, such as human voice, body movement, physical touch, or pressure, into electrical signals as input data input to the computing system 1500 via I / O port 1508. In some instances, such input may differ from the various systems and methods discussed with respect to the preceding diagrams. Similarly, the output device can convert electrical signals received from the computing system 1500 via I / O port 1508 into signals that can be sensed or used by the various methods and systems discussed herein. The input device may be an alphanumeric input device comprising alphanumeric keys and other keys for transmitting information and / or command selection to the processor 1502 via I / O port 1508.

[0128] An ambient transducer device converts one form of energy or signal into another form of energy or signal for input to or output from the computing system 1500 via I / O port 1508. For example, an electrical signal generated within the computing system 1500 can be converted into another type of signal, and / or vice versa. In one embodiment, the ambient transducer device senses characteristics or aspects of the environment, either locally or remotely from the computing device 1500, such as battery voltage, open-circuit battery voltage, charging current, battery temperature, light, sound, temperature, pressure, magnetic field, electric field, chemical properties, etc.

[0129] In one implementation, communication port 1510 may be connected to a network through which computer system 1500 can receive network data useful for performing the methods and systems described herein and for transmitting information and network configuration changes determined thereby. For example, charging protocols may be updated, battery measurement or calculation data may be shared with external systems, etc. Communication port 1510 connects computer system 1500 to one or more communication interface devices configured to transmit and / or receive information between computer system 1500 and other devices via one or more wired or wireless communication networks or connections. Examples of such networks or connections include, but are not limited to, Universal Serial Bus (USB), Ethernet, Wi-Fi, Bluetooth®, Near Field Communication (NFC), Long Term Evolution (LTE), etc. One or more such communication interface devices may be used via communication port 1510 to communicate directly with one or more other machines via a point-to-point communication path, via a wide area network (WAN) (e.g., the Internet), via a local area network (LAN), via a cellular network (e.g., third-generation (3G), fourth-generation (4G), fifth-generation (5G)) network, or via another communication component.

[0130] Computer system 1500 may include a subsystem port 1512 for communicating with one or more systems, relating to charging a device to control the operation of the device and / or exchanging information between computer system 1500 and one or more subsystems of the device according to the methods and systems described herein. Examples of such subsystems of a vehicle include, but are not limited to, motor controllers and systems, battery control systems, etc.

[0131] Figure 15 The system described herein is merely one possible example of a computer system that can be adopted or configured according to various aspects of this disclosure. It should be understood that other non-transitory tangible computer-readable storage media storing computer-executable instructions may be used to implement the currently disclosed techniques on a computing system.

[0132] It is recognized that battery electrolytes in a solid (frozen) or partially solid state should be charged at a lower rate than those in a liquid or partially liquid state. Furthermore, it is recognized that liquid electrolytes can be composed of different components that undergo phase transitions at different temperatures, such as from solid (frozen) to liquid. Therefore, as the electrolyte is heated, it may undergo more than one phase transition. The charge rate can vary at these different phase transition temperatures. For example, as the battery is heated and the electrolyte undergoes one or more phase transitions, the charge rate may increase at each phase transition.

[0133] In the case of a single battery cell or a small number of battery cells, one or more temperature probes can be used to measure the temperature. In the case of a larger battery pack, temperature probes may not be sufficient to assess the temperature gradient of the entire pack. Furthermore, in some cases, the system may not be equipped with temperature probes, and therefore some other methods of identifying phase transitions in the electrolyte would be beneficial.

[0134] In one instance, such as Figure 16 As can be seen, a strong correlation has been found between peak susceptance and phase transition within the electrolyte. In the depicted cell (a 3000 mAh lithium-ion battery cell, such as the Samsung 30T cell), it should be understood that as the temperature rises from below -10°C to above -10°C (at approximately -10°C), the electrolyte changes from a solid to a liquid, and similarly, as the temperature increases above 0°C, another component of the electrolyte changes from a solid to a liquid. Further, it can be seen in the graph that the frequency of peak susceptance decreases steadily from approximately -20°C to approximately -10°C as the temperature increases. At -10°C, there is an inflection point or other changes in the rate of change of peak susceptance. Similarly, at 0°C, the rate of change of peak susceptance changes. Therefore, a change in the charging signal can be triggered when the rate of change of the peak susceptance value changes or when an inflection point is present. More generally, the charging signal can be changed when the phase transition of the electrolyte is detected.

[0135] More specifically, a battery charging system can be configured to apply a charging signal of some form to the battery. In one example, the charging current is a DC charging current, which will be mentioned in the following discussion. However, as discussed herein, other charging signals can be used, including charging signals with a shaped leading edge, charging signals with a body portion, and / or charging currents with a rest period. Various properties of the charging signal, including the frequency shape of the leading edge, the overall period, the duration of the body and / or the rest period, the harmonic components of the charging signal, and the magnitude of the charging current, can vary in response to phase transitions of the electrolyte, such as those achieved by temperature measurements, susceptance measurements, or otherwise. Furthermore, specific “heating” portions of the charging signal can be applied individually or in combination.

[0136] When charging is initiated at a relatively low temperature where some or all of the battery electrolyte can be frozen (in a solid or semi-solid state), the system obtains a susceptance value during charging, which may be the frequency of the peak susceptance. As the battery is charged (and heated), the system obtains the frequency of the peak susceptance value. The system can measure certain properties of the charging current and / or battery voltage to assess the susceptance. The system can modify the charging signal upon recognizing a change in the susceptance value, such as a change in the rate of change of the peak susceptance frequency. Changes in susceptance are related to a phase transition of the electrolyte, which may be a change to a liquid state. When the electrolyte or some of its properties liquefy, it can accept more charging current. Therefore, the system can increase the amount of charging current. The system can also modify other properties of the charging signal to increase the charging energy entering the battery.

[0137] The system can also directly measure temperature, either alone or in combination with susceptance. For example, the system can use the overall temperature of the group or the ambient temperature as a trigger condition for running the methods discussed herein; however, it should be noted that this may not be necessary at relatively high temperatures where the electrolyte is known to be in liquid form. Direct temperature measurements can also be used directly as an indicator of electrolyte phase transitions.

[0138] Depending on the initial conditions (e.g., the battery temperature when charging is to begin), the system may preheat the battery before charging begins (e.g., as per [reference to...]). Figure 8 (As discussed in step 804). The system can also use Figure 9A and 9B The system uses the signals described in the diagram to charge and heat the battery. The system can also simply use the heating signals described in the rest cycle to initially heat the battery, either alone or in combination with heating, before transitioning to a portion of the charging process. The system can determine the point of contagion of peak susceptance to alter the charging process (e.g., increase charge), or transition from heating to charging, or from heating to a combination of heating and charging, as described in the diagram. Figure 9A and 9B As shown in the image.

[0139] Embodiments of this disclosure include various operations described herein. These operations may be performed by hardware components or embodied in machine-executable instructions that can be used to cause a general-purpose or special-purpose processor programmed with those instructions to perform the operations. Alternatively, the operations may be performed by a combination of hardware, software, and / or firmware.

[0140] Various modifications and additions may be made to the exemplary embodiments discussed without departing from the scope of this disclosure. For example, while the embodiments described above are also referred to as implementations or examples with reference to specific features, the scope of the invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Therefore, the scope of the invention is intended to cover all such alternatives, modifications, and variations, as well as all equivalents thereof.

[0141] While specific implementations, examples, and embodiments (terms used synonymously herein) are discussed, it should be understood that this is for illustrative purposes only. Those skilled in the art will recognize that other components and configurations may be used without departing from the spirit and scope of this disclosure. Therefore, the descriptions and figures are illustrative and should not be construed as restrictive. Many specific details are described to provide a thorough understanding of this disclosure. However, in some instances, well-known or conventional details have not been described to avoid obscuring the description.

[0142] The reference to "an embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. The phrases "in one embodiment" or similar phrases appearing in various places throughout this specification do not necessarily all refer to the same embodiment, nor are they separate or alternative embodiments that are mutually exclusive with other embodiments. Furthermore, various features that may be exhibited by some embodiments but not by others are described.

[0143] The terms used in this specification generally have their general meaning in the art within the context of this disclosure and in the specific context in which each term is used. Alternative language and synonyms may be used for any one or more of the terms discussed herein, and should not be given a special meaning regardless of whether the term is described or discussed in detail herein. In some cases, synonyms for specific terms are provided. The description of one or more synonyms does not preclude the use of other synonyms. Examples used anywhere in this specification (including examples of any terms discussed herein) are merely illustrative and are not intended to further limit the scope and meaning of this disclosure or any example terms. Similarly, this disclosure is not limited to the various embodiments given in this specification.

[0144] Without limiting the scope of this disclosure, examples of instruments, apparatus, methods, and related results according to embodiments of this disclosure are given below. It should be noted that headings or subheadings may be used in these examples for the reader's convenience, and this should in no way limit the scope of this disclosure. Unless otherwise defined, the technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the event of any conflict, this document (including the definitions) shall prevail.

[0145] Various features and advantages of this disclosure are set forth in the description and will be apparent in part from the description, or may be learned by practicing the principles disclosed herein. The features and advantages of this disclosure may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims.

Claims

1. A method for charging a low-temperature battery, comprising: Obtain the susceptance response of the battery, and When the susceptance response of the battery changes, the charging signal transmitted to the battery is changed.

2. The method of claim 1, wherein the change in the susceptance response is related to the phase transition of the electrolyte of the battery.

3. The method according to claim 1, wherein the susceptance response is the frequency of the peak susceptance.

4. The method of claim 3, wherein the change in the susceptance response is a change in the rate of change of the frequency of the peak susceptance.

5. The method of claim 2, wherein changing the charging signal includes increasing the charging current value when the susceptance response is related to the phase transition from electrolyte to liquid.

6. The method of claim 1, further comprising: The battery is heated using an alternating current waveform.

7. The method of claim 6, wherein the AC waveform is a portion of the charging signal, the charging signal further comprising a DC component, and the method further comprising: When the susceptance response of the battery changes, the charging signal transmitted to the battery is changed by increasing the magnitude of the DC portion of the charging signal.

8. The method of claim 7, further comprising interrupting the AC portion of the charging signal.

9. The method of claim 7, wherein the DC portion of the charging signal further includes a shaped leading edge that transitions to the DC portion.

10. The method of claim 9, wherein the charging signal comprises a repetitive charging waveform, the repetitive charging waveform comprising the shaped leading edge, the DC portion, and the rest period.

11. A method for charging a low-temperature battery, comprising: Obtain measurements of the phase transition of the electrolyte in the indicator battery; as well as When the phase transition of the electrolyte in the battery is detected, the charging signal transmitted to the battery is changed.

12. The method of claim 11, wherein the measured value is a temperature measurement value.

13. The method of claim 11, wherein the measured value is a measurement of the frequency of the peak susceptance.

14. The method of claim 11, wherein the phase transition is a change in the electrolyte from solid to liquid as the temperature increases.

15. The method of claim 13, wherein identifying the phase transition includes identifying a change in the rate of change of the frequency of the peak susceptance as the battery heats up.

16. The method of claim 11, wherein changing the charging signal includes increasing the charging current value.

Images