System for controlling battery charging

Abstract

A system for controlling charging of a battery includes a charging circuit for supplying a charging current or voltage to the battery, where the charging circuit is configured to periodically detect an impedance of the battery and control the charging current or voltage based on the detected impedance.

Description

Technical Field

[0001] The present disclosure relates to a system for controlling battery charging. Background Art

[0002] Portable electronic devices, such as mobile phones, tablet computers, and laptop computers, portable media players, virtual reality (VR) or augmented reality (AR) headsets, portable gaming devices, etc., are typically powered by rechargeable batteries.

[0003] The charging performance of a battery, such as the charging speed (e.g., the time required to reach a given charge level at a given charging current) or the charging efficiency, can vary depending on the temperature of the battery. For some battery chemistries, the charging performance can be improved or optimized if the battery is maintained within a predetermined temperature range during charging. Summary of the Invention

[0004] According to a first aspect, the present invention provides a system for controlling battery charging, the system comprising: a charging circuit for supplying a charging current or voltage to the battery, wherein the charging circuit is configured to periodically detect an impedance of the battery and control the charging current or voltage based on the detected impedance.

[0005] The system may further include a heating arrangement for heating the battery. The charging circuit may be configured to control the heating arrangement based on the detected impedance of the battery to maintain the temperature of the battery within a predefined charging range.

[0006] The charging circuit may be configured to detect a voltage and a current of the battery and detect the impedance based on the detected voltage and current.

[0007] The charging circuit may be configured to infer the temperature of the battery based on the detected impedance.

[0008] The system may further include a heating arrangement for heating the battery. The charging circuit may be configured to control the heating arrangement based on the inferred temperature of the battery.

[0009] The charging circuit may be configured to control the heating arrangement based on the inferred temperature of the battery and one or more of the following: the state of charge (SoC) of the battery; and the state of health (SoH) of the battery.

[0010] The charging circuit may be configured to control the charging current supplied to the battery based on the inferred temperature of the battery.

[0011] The charging circuit may be configured to control the charging current supplied to the battery based on the inferred temperature of the battery and one or more of the following: the state of charge (SoC) of the battery; and the state of health (SoH) of the battery.

[0012] The charging circuit may be configured to detect the impedance of the battery at a plurality of different frequencies or frequency ranges, and infer the temperature of the battery based on the impedance detected at the plurality of different frequencies or frequency ranges.

[0013] The charging circuit may be configured to monitor the load current drawn from the battery, and detect the impedance of the battery at the plurality of different frequencies or frequency ranges based on the monitored load current to generate an electrochemical impedance spectroscopy (EIS) measurement output of the battery.

[0014] The charging circuit may be configured to control a current-consuming device to draw additional current from the battery if the frequency components of the monitored load current are insufficient to detect the impedance of the battery at a minimum number of different frequencies or frequency ranges.

[0015] The charging circuit may be configured to determine a quality metric of the load current based on the spectral components and amplitude of the load current, and control the current-consuming device to draw the additional current from the battery if the quality metric is below a predefined threshold.

[0016] The charging circuit may be configured to compare the EIS measurement output generated by the charging circuit for the battery with a set of reference EIS measurement outputs to infer the temperature of the battery.

[0017] The system may be configured to: receive a temperature measurement of the host device when the host device including the system is inactive or in a sleep or idle operation mode; detect the impedance of the battery when the host device is inactive or in the sleep or idle operation mode; and calibrate the system using the received temperature measurement and the detected impedance when the host device is inactive or in the sleep or idle operation mode.

[0018] The heating arrangement may include a coil for inductive power transfer between a host device including the system and another device.

[0019] The heating arrangement may include an array of resistive elements disposed near the battery when using the system.

[0020] The heating arrangement may include a circuit configured to supply a signal or waveform to the battery to cause a temperature change of the battery by changing the resistive losses in the battery.

[0021] The circuit may be configured to supply a time-varying current or voltage signal to the battery.

[0022] When the system is connected to a power source external to the system, the charging circuit may be operative to: detect the impedance of the battery; determine the temperature of the battery based on the detected impedance; and output a heating control signal to cause the heating arrangement to heat the battery if the determined temperature of the battery is below a predetermined battery temperature range.

[0023] The charging circuit may also be operative to delay charging of the battery until the temperature of the battery reaches the predetermined battery temperature range.

[0024] According to a second aspect, the present invention provides a system for controlling battery charging, the system comprising: a charging circuit configured to: detect the impedance of the battery; infer the temperature of the battery based on the detected impedance of the battery; and supply a charging current to the battery, wherein the charging current is based on the inferred temperature of the battery.

[0025] According to a third aspect, the present invention provides a system for controlling battery charging, the system comprising: a heating arrangement for heating the battery; a charging circuit configured to detect the temperature of the battery and control the heating arrangement based on the detected temperature to maintain the impedance of the battery within a predefined impedance range for charging.

[0026] According to a fourth aspect, the present invention provides a system for estimating the temperature of a battery, wherein the system is configured to: monitor a load current drawn from the battery; detect the impedance of the battery at a plurality of different frequencies or frequency ranges based on the monitored load current to generate an Electrochemical Impedance Spectroscopy (EIS) measurement output of the battery; and estimate the temperature of the battery based on the EIS measurement output.

[0027] The system may also be configured to receive a State of Charge (SoC) and / or a State of Health (SoH) of the battery and estimate the temperature of the battery based on a combination of the EIS measurement output and the SoC and / or SoH.

[0028] The system may be configured to compare the EIS measurement output with a set of reference EIS measurement outputs to infer the temperature of the battery.

[0029] The system may also be configured to: receive a state of charge (SoC) and / or a state of health (SoH) of the battery; select at least one reference EIS measurement output based on the received SoC and / or SoH; and estimate the temperature of the battery based on the selected at least one reference EIS measurement output and the EIS measurement output generated by the system.

[0030] The system may be configured to control a current-consuming device to draw additional current from the battery if the frequency components of the monitored load current are not sufficient to detect the impedance of the battery at a minimum number of different frequencies or frequency ranges.

[0031] The system may be configured to determine a quality metric of the load current based on the spectral components and amplitude of the load current, and if the quality metric is below a predefined threshold, control the current-consuming device to draw the additional current from the battery.

[0032] The system may be configured to: receive a temperature measurement of the host device when the host device including the system is inactive or in a sleep or idle operation mode; detect the impedance of the battery when the host device is inactive or in the sleep or idle operation mode; and calibrate the system using the received temperature measurement and the detected impedance when the host device is inactive or in the sleep or idle operation mode.

[0033] According to a third aspect, the present invention provides a system for controlling battery charging, the system including: a charging circuit for supplying a charging current to the battery; and a heating arrangement for heating the battery, wherein the charging circuit is configured to detect the impedance of the battery and control the heating arrangement based on the detected impedance to maintain the temperature of the battery within a predefined temperature range for charging.

[0034] According to a sixth aspect, the present invention provides an integrated circuit including the system according to any one of the first to fifth aspects.

[0035] According to a seventh aspect, the present invention provides a host device including the system according to any one of the first to fifth aspects.

[0036] The host device may include a laptop, notebook, netbook or tablet computer, gaming device, game console, controller for a game console, virtual reality (VR) or augmented reality (AR) device, mobile phone, portable audio player, portable device, or accessory device used in conjunction with a laptop, notebook, netbook or tablet computer, gaming device, game console, VR or AR device, mobile phone, portable audio player or other portable device.

[0037] Throughout this specification, the word "comprise", or variations such as "comprises" or "comprising", should be understood to mean including the stated element, integer or step, or group of elements, integers or steps, but not excluding any other element, integer or step, or group of elements, integers or steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Embodiments of the present invention will now be described, by way of example only and with strict reference to the drawings, in which:

[0039] Figure 1 is a schematic diagram of a battery-powered electronic device having a charging system for charging the battery of the device according to the present disclosure;

[0040] Figure 2 is a schematic diagram of a battery-powered electronic device having an alternative charging system for charging the battery of the device according to the present disclosure;

[0041] Figures 3a to 3d is a graph showing exemplary electrochemical impedance spectroscopy (EIS) measurement outputs of the battery in different charging states; and

[0042] Figure 4 is a schematic diagram of a battery-powered electronic device having a battery temperature estimation system according to the present disclosure. DETAILED DESCRIPTION

[0043] First, with reference to Figure 1 , a battery-powered electronic device is generally designated 100. The battery-powered electronic device 100 can be, for example, a mobile phone, a tablet or a laptop computer, a portable media player, a virtual reality (VR) or augmented reality (AR) headset, a portable gaming device, etc. The battery-powered electronic device includes a battery 110 that supplies electrical power to a load 120. The load 120 can include one or more components or subsystems of the battery-powered electronic device 100, such as a processing subsystem, a display subsystem, an audio subsystem, a user input subsystem, etc.

[0044] The battery-powered electronic device 100 further includes a charging system 130 for charging the battery 110. The charging system 130 is configured to receive a power supply from a power source or a charging device 150 (such as a main power charger external to the battery-powered electronic device 100), and supply a charging current or voltage to the battery 110. The charging system 130 includes a charging circuit 132, and may further include a heating arrangement 134. In some examples, the charging system 130 may further include a current sink 136. The charging circuit 132 may be implemented as a separate IC, or may be implemented in an IC such as a fuel gauge IC.

[0045] The charging circuit 132 is configured to supply a charging current or voltage to the battery 110. The charging circuit 132 is further configured to (periodically or continuously) detect the impedance of the battery 110, and control the charging current or voltage based on the detected impedance of the battery 110. The charging circuit 132 may additionally or alternatively control the heating arrangement 134 (if provided) based on the detected impedance of the battery 110 to maintain the temperature of the battery within a predefined temperature range to optimize or at least improve the charging performance of the battery.

[0046] In some examples, the charging circuit 132 is configured to detect the voltage of the battery 110 and the load current drawn from the battery 110 by the load 120, and determine or estimate the impedance of the battery 110 based on the detected voltage and current by dividing the detected voltage by the detected current. To this end, the charging circuit 132 may include a voltage detection circuit 138 configured to output a signal indicating the battery voltage; a current detection circuit 140 configured to output a signal indicating the load current; and a processing circuit 142 configured to determine or estimate the impedance of the battery 110 based on the signals output by the voltage detection circuit 138 and the current detection circuit 140. The current detection circuit 140 may be configured to detect the voltage across a current sense resistor 144 in the current path between the battery 110 and the load 120. The current sense resistor 144 may be provided as part of the charging system 130, as Figure 1 shown, or alternatively may be located external to the charging system 130. The charging circuit 132 may be configured to continuously monitor the battery voltage and the load current in real time, so that the impedance of the battery 110 can be continuously determined or estimated, or may be configured to sample the battery voltage and the load current periodically, so that the resistance of the battery 110 can be periodically determined or estimated. In some examples, the charging circuit 132 may include a "fuel gauge" integrated circuit (IC) configured to measure the battery voltage and current in real time.

[0047] The impedance of the battery 110 depends on many different factors, including the temperature of the battery 110, the state of charge (SoC) of the battery 110 (which can be defined as the ratio or percentage of the remaining charge in the battery 110 to the maximum charge storage capacity of the battery 110), the state of health (SoH) of the battery 110 (which is a measure indicating the degree of battery degradation and the remaining capacity and can be defined as the ratio or percentage of the maximum charge that the battery 110 can supply at a given time to the rated capacity of the battery 110), and the frequency of the current drawn from the battery 110.

[0048] In some examples, the charging circuit 132 is configured to infer the temperature of the battery 110 based on the determined impedance of the battery 110 and supply a heating control signal to the heating arrangement 134 such that the heating arrangement 134 maintains the battery 110 within a predetermined battery temperature range for charging the battery 110.

[0049] The heating control signal can be based on the inferred temperature of the battery 110. For example, if the inferred temperature of the battery 110 is below a first temperature threshold (which can represent the lower limit or limit of the predetermined battery temperature range for charging the battery), the charging circuit 132 can output an appropriate heating control signal to cause the heating arrangement 134 to increase the amount of heat supplied to the battery 110, thereby increasing the temperature of the battery 110 to within the predetermined battery temperature range. If the inferred temperature of the battery 110 is above a second temperature threshold (which can represent the upper limit or limit of the predetermined battery temperature range for charging the battery), the charging circuit 132 can output an appropriate heating control signal to cause the heating arrangement 134 to reduce the amount of heat supplied to the battery 110 to reduce the temperature of the battery 110 to within the predetermined battery temperature range.

[0050] The charging circuit 132 continues to monitor the impedance of the battery 110 and infer the temperature of the battery 110 during battery charging and adjusts the heating control signal as needed to maintain the temperature of the battery 110 within the predetermined battery temperature range. Thus, the charging circuit 132 uses the detected impedance of the battery 110 as a feedback variable to control the heating control signal in order to regulate the temperature of the battery 110.

[0051] Some battery-powered electronic devices may schedule the charging of battery 110 when they are connected to a charging device. For example, when a battery-powered electronic device 100 such as a mobile phone is connected to a charging device 150 (e.g., when a charger is connected to the charging port of device 100), if the charge state of battery 110 is higher than a minimum charge threshold, the control system of the device may schedule the start of charging at a later time. In this case, the charging circuit 132 may output an appropriate heating control signal to cause the heating arrangement 134 to heat battery 110 at an appropriate time so that it is within a predetermined battery temperature range at the scheduled start time of charging.

[0052] In other examples, when the battery-powered electronic device 100 is connected to an external power source or a charging device 150, the control system of device 100 may cause the charging circuit 132 to detect the impedance of battery 110 and infer, estimate, or otherwise determine the temperature of battery 110 based on the detected impedance. If the temperature of battery 110 is below a predetermined battery temperature range, the charging circuit 132 may output an appropriate heating control signal to cause the heating arrangement 134 to heat battery 110, and the charging circuit 132 may delay the charging of battery 110 until the temperature of battery 110 reaches the predetermined battery temperature range.

[0053] In these examples, charging of the battery will only begin when the battery is at a temperature where charging may be optimized or improved.

[0054] In other examples, when device 100 is connected to a charging device, the control system of device 100 may cause the charging circuit 132 to determine the impedance of battery 110 and infer, estimate, or otherwise determine the temperature of battery 110 based on the detected impedance. If the temperature of battery 110 is below a predetermined battery temperature range, the charging circuit 132 may output an appropriate heating control signal to cause the heating arrangement 134 to heat battery 110, and may also immediately begin charging battery 110 such that the charging of battery 110 initially occurs when battery 110 is at a sub-optimal charging temperature, but the charging performance improves as the battery temperature reaches the predetermined battery temperature range.

[0055] The heating control signal can be, for example, a voltage or current directly supplied to the heating arrangement 134, or it can be a switching control signal such as a pulse width modulation (PWM) signal for modulating the operation of a switch that controls the supply of voltage or current to the heating arrangement 134.

[0056] In some examples, in addition to determining or estimating the impedance of battery 110, the charging circuit 132 may be configured to receive information (e.g., a signal) indicative of the battery SoC and / or SoH and / or the frequency of the load current, and / or estimate, calculate, or otherwise determine the frequency of the battery SoC and / or SoH and / or the load current. The charging circuit 132 may use this additional information in combination with the determined impedance of the battery 110 to infer the temperature of the battery 110. Using such additional information related to other battery parameters (e.g., SoC, SoH) of the electronic device 100 and / or operating parameters (e.g., the frequency of the load current) may enable the charging circuit 132 to more accurately infer the temperature of the battery 110, and thus control the temperature of the battery 110 more accurately than by using only the impedance of the battery 110 to infer the temperature of the battery 110.

[0057] In some examples, in addition to or instead of controlling the temperature of the battery 110 based on the determined impedance of the battery 110, the charging circuit 132 may control the charging current supplied to the battery 110 based on the detected impedance of the battery 110 to optimize or improve the charging performance of the battery 110.

[0058] In some examples, the charging circuit 132 may infer the battery temperature based on the determined impedance (and optionally also based on additional information such as battery SoC, battery SoH, and / or the frequency of the load current), and may control the charging current based on the inferred battery temperature to select a charging current that improves or optimizes the charging of the battery 110 for the inferred battery temperature.

[0059] The charging circuit 132 may determine the charging current to be supplied to the battery by inputting the inferred battery temperature into a mathematical function, relationship, or model that correlates battery temperature and charging current. Alternatively, the charging circuit 132 may determine the charging current by selecting an appropriate charging current from a look-up table that contains battery temperature values and corresponding charging current values for the inferred battery temperature.

[0060] In an alternative example, the charging circuit 132 may omit inferring the temperature of the battery 110 from the determined battery impedance, but may instead control the heating arrangement 134 based on the determined battery resistance such that the heating arrangement 134 maintains the battery 110 within a predetermined battery temperature range for charging the battery 110.

[0061] In such examples, the charging circuit 132 continues to monitor the impedance of the battery 110 during battery charging and adjusts the heating control signal as needed to maintain the impedance of the battery 110 within a predetermined battery impedance range. Thus, the charging circuit 132 uses the determined impedance of the battery 110 as a feedback variable to control the heating control signal in order to regulate the impedance of the battery 110.

[0062] In such examples, the charging circuit 132 may determine the charging current to be supplied to the battery 110 by inputting the determined battery impedance into a mathematical function, relationship, or model that correlates the battery impedance (and optionally other parameters such as the battery SoC and / or battery SoH) with the charging current.

[0063] Alternatively, the charging circuit 132 may determine the charging current by selecting an appropriate charging current from a look-up table that contains battery impedance values (and optionally other parameters such as the battery SoC and / or battery SoH) and corresponding charging current values for the determined battery impedance (and optionally other parameters such as the battery SoC and / or battery SoH).

[0064] The charging circuit 132 may be configured to perform a calibration process periodically (e.g., daily) or in response to a predefined calibration trigger condition (e.g., when the device 100 is powered on, or after a predefined idle period of the device 100) to calibrate the battery temperature inference algorithm that the charging circuit 132 uses to infer the temperature of the battery 110 based on the detected battery impedance.

[0065] When the device 100 is in a stationary state (e.g., when the device is inactive or in a sleep or idle operating mode), the charging circuit 132 may receive, for example, a signal indicating the temperature of the device 100 from an on-board device temperature sensor. Since the device is stationary at this time, it can be assumed that the temperature of the battery 110 is similar to the temperature of the device 100. The charging circuit 132 then measures the impedance of the battery 110 while the device is stationary, for example, by supplying a known excitation signal to the battery 110, or by applying a known load to the battery 110 and measuring the battery voltage and current. The charging circuit 132 may then use the measured battery impedance and the device temperature as calibration data points to calibrate or re-calibrate the battery temperature inference algorithm.

[0066] Figure 2 is a schematic representation of an example of an alternative charging system for charging the battery of a battery-powered electronic device. Similar to Figure 1 the battery-powered electronic device 100, the battery-powered device 200 may be, for example, a mobile phone, a tablet or laptop computer, a portable media player, a virtual reality (VR) or augmented reality (AR) headset, a portable gaming device, etc.

[0067] Figure 1 the battery-powered electronic device 100 and Figure 2 the battery-powered electronic device 200 have many common features. These common features are denoted by common reference numerals in Figure 1 and Figure 2 and will not be described in detail here for the sake of clarity and brevity.

[0068] The battery-powered electronic device 200 includes a battery temperature sensing arrangement 210 configured to detect the temperature of the battery 110. The battery temperature sensing arrangement 210 can be a dedicated battery temperature sensing arrangement and can include, for example, temperature sensing elements (such as thermistors, diodes, transistors, etc.) or an array of temperature sensing units integrated with or disposed on or in or near the battery 110. The battery temperature sensing arrangement 210 is coupled to the charging circuit 132 and outputs a signal (such as a voltage or current) indicative of the temperature of the battery 110 to the charging circuit 132.

[0069] Alternatively, the battery temperature sensing arrangement 210 can be provided by a component of the device 100 that is primarily used for some other purpose. For example, the battery temperature sensing arrangement 210 can be provided by a coil that is primarily used for inductive power transfer between the device 100 and another device (such as a wireless charging device or another battery-powered electronic device (such as a mobile phone)). A suitable system for using this coil to sense and report the temperature of the battery 110 is described in U.S. Patent Application No. 18 / 313,821, filed on May 8, 2023, the content of which is incorporated herein by reference in its entirety.

[0070] Therefore, Figure 2 in the example shown, the charging circuit 132 does not need to determine the impedance of the battery 110 in order to supply a heating control signal to the heating arrangement 134 to keep the battery 110 within a predetermined battery temperature range for charging the battery 110, or to keep the battery 110 within a predetermined battery impedance range for charging the battery 110.

[0071] Alternatively, Figure 2 in the example shown, the charging circuit 132 can supply a heating control signal to the heating arrangement 134 based on the temperature of the battery 110 detected by the battery temperature sensing arrangement 210 to maintain the battery 110 within a predetermined battery temperature range or a predetermined battery impedance range for charging the battery 110.

[0072] The charging circuit 132 continues to monitor the temperature of the battery 110 (as detected by the battery temperature sensing arrangement 210) during charging of the battery 210 and adjusts the heating control signal as needed to keep the temperature of the battery 110 within a predetermined battery temperature range for charging. Thus, the charging circuit 132 uses the detected temperature of the battery 110 as a feedback variable to control the heating control signal in order to regulate the temperature or impedance of the battery 110.

[0073] Figure 2In the example, the charging circuit 132 can control the charging current supplied to the battery 110 based on the detected battery temperature to select a charging current that improves or optimizes the charging of the battery 110 for the detected battery temperature.

[0074] The charging circuit 132 can determine the charging current to be supplied to the battery by inputting the detected battery temperature into a mathematical function, relationship, or model that correlates battery temperature and charging current. Alternatively, the charging circuit 132 can determine the charging current by selecting an appropriate charging current for the inferred battery temperature from a look-up table that contains battery temperature values and corresponding charging current values.

[0075] The above references Figure 1 and Figure 2 The examples described both include a heating arrangement 134. The heating arrangement can include a dedicated heating component (such as a resistive heating element or an array of resistive elements) that is disposed near the battery 110 (when using the charging system 130) to transfer heat to the battery.

[0076] Alternatively, the heating arrangement 134 can be provided by a component of the device 100 that is primarily used for some other purpose. For example, the heating arrangement can be provided by a circuit such as a processing circuit (e.g., a processor integrated circuit) that is disposed near the battery 110. When heating of the battery 110 is required, the processing circuit can be controlled to perform a redundant function, such as a calculation whose result is not used for any purpose, so that the processing circuit dissipates heat that is transferred to the battery 110.

[0077] As another example, the heating arrangement 134 can be provided by a coil that is primarily used for inductive power transfer between the device 100 and another device (such as a wireless charging device or another battery-powered electronic device (such as a mobile phone)). A suitable system for heating the battery 110 using such a coil is described in U.S. Patent Application No. 18 / 313,821, filed on May 8, 2023, the content of which is incorporated herein by reference in its entirety.

[0078] In another alternative example, the heating arrangement 134 can include a circuit (such as a waveform generator circuit) that is configured to supply a signal or waveform (such as a current or voltage signal waveform) to the battery 110 to cause a change (such as an increase) in the temperature of the battery 110 by changing (such as increasing) the resistive losses in the battery.

[0079] The signal or waveform can be, for example, a voltage or a current whose amplitude varies (over time) around a central value between a positive peak amplitude and a negative peak amplitude. In some examples, the signal or waveform can be a sinusoidal signal or waveform.

[0080] When the signal or waveform is a variable current, the heat generated by the battery is equal to I 2R (where I is the average current amplitude of the variable current signal, and R is the resistance of the battery 110), and thus an increase in the variable current signal amplitude will increase the heat generated by the battery 110. The variable current signal can vary about a central value of 0 amperes, in which case the amplitude of the variable current signal will vary between +I and -I (where I is the peak current amplitude), or alternatively can vary about some value offset from 0 amperes (such as 1 ampere, 2 amperes, etc.), in which case the amplitude of the variable voltage signal will vary between O+I and O-I (where O is the offset value). Since the heat generated by the battery 110 is proportional to I 2 is proportional, a varying current signal that varies about a central value offset from 0 amperes will cause the battery to generate more heat than a varying current signal of the same peak amplitude that varies about a central value of 0 amperes.

[0081] Similarly, when the signal or waveform is a variable voltage, the heat generated by the battery is equal to V 2 / R (where V is the average voltage amplitude of the variable voltage signal), and thus increasing the amplitude of the variable voltage signal will increase the heat generated by the battery 110. The variable voltage signal can vary about a central value of 0 volts, in which case the amplitude of the variable current signal will vary between +V and -V (where V is the peak voltage amplitude), or alternatively can vary about some value offset from 0 volts (such as 1 volt, 2 volts, etc.), in which case the amplitude of the variable voltage signal will vary between O+V and O-V (where O is the offset value). Since the heat generated by the battery 110 is proportional to I 2 is proportional, a varying voltage signal that varies about a central value offset from 0 volts will cause the battery to generate more heat than a varying voltage signal of the same peak amplitude that varies about a central value of 0 volts.

[0082] In the example described above with reference to Figure 2 the charging circuit 132 receives a battery temperature signal from the battery temperature sensor arrangement and uses this signal to regulate the temperature and / or impedance of the battery 110 within a predefined battery temperature and / or impedance range, and / or control the charging current supplied to the battery 110. In contrast, in the example described above with reference to Figure 1 the charging circuit 132 infers, estimates, or otherwise determines the temperature of the battery 110 based on the detected impedance of the battery 110.

[0083] In some applications, inferring the battery temperature based on the detected, measured, or otherwise determined battery impedance helps to improve the charging and / or discharging performance of the battery because inferring the temperature can provide a more accurate indication of the battery temperature compared to measuring the battery temperature using a temperature sensing arrangement.

[0084] In particular, as part of an overall trend to increase the capacity and lifespan of batteries in portable electronic devices, the physical size of the batteries in such devices continues to increase. Accurately and reliably measuring the temperature of such a battery can pose significant challenges without using a large number of temperature sensors distributed on and / or within the battery. The temperature of the battery can be measured using a temperature sensor provided on an IC (such as a battery fuel gauge IC) coupled to the battery. However, such sensors can be affected by the battery charging current, which can make the fuel gauge IC hotter than the battery itself, resulting in inaccurate temperature measurements.

[0085] In addition, even when using an array of temperature sensors distributed on and / or within the battery, accurately measuring the battery temperature can still be challenging because local hotspots can occur within the battery. If any single temperature sensor in the sensor array is located near this local hotspot, the temperature reported by that sensor will reflect the temperature of the hotspot rather than the lower temperature of the rest of the battery.

[0086] Thus, in many applications, inferring the battery temperature based on the detected impedance of the battery may be more desirable than directly attempting to measure the battery temperature.

[0087] As mentioned above, the impedance of a battery-powered electronic device (such as device 100 or 200) during normal operation can be measured by detecting the voltage and current of the battery. The battery impedance can then be calculated by dividing the detected voltage / current. The battery voltage and current can be measured in real time, for example, using an IC coupled to the battery, such as a battery fuel gauge IC.

[0088] The impedance of a battery typically varies with frequency, temperature, SoC, and / or SoH. The effect of frequency on battery impedance can be quantified using a technique called electrochemical impedance spectroscopy (EIS), in which an excitation signal (such as a current) of variable frequency is applied to the battery, and the impedance of the battery is determined as the frequency of the excitation signal is varied to form a relationship curve of battery impedance versus frequency. By performing EIS measurements on the battery at different charge states and / or health states, a model of the battery impedance under different conditions can be developed.

[0089] It has been found that, at a given SoC and SoH, the EIS measurement value changes by approximately 7% per degree Celsius. Accordingly, the present disclosure proposes using either the dynamic EIS (or EIS-like) measurement value of the battery impedance alone or in combination with additional information such as the battery SoC and / or SoC to infer the battery temperature. As described above, the charging system 130 including the charging circuit 132 of the above type can control the heating arrangement 134 and / or the charging current supplied to the battery 110 by the charging circuit 132 based on the inferred battery temperature.

[0090] Accordingly, the charging circuit 132 (e.g., the processing circuit 142) can be configured to perform dynamic EIS (or EIS-like) measurements of the battery 110 to infer the temperature of the battery 110. Such EIS (or EIS-like) measurements can be performed in real time, i.e., while the device 100 / 200 is operating. The charging circuit 132 is configured to monitor the load current drawn from the battery 110 and use this load current as an alternative to a dedicated EIS excitation signal supplied to the battery 110. Thus, the instantaneous load current drawn from the battery 110 by the load 120 acts as an effective EIS excitation signal. This allows EIS measurements to be performed in real time without the need for a dedicated EIS measurement time during which a dedicated EIS excitation signal is applied to the battery 110 while the battery 110 is not under significant load.

[0091] The charging circuit 132 can monitor the load current drawn from the battery 110 by the load 120 and determine a quality metric based on the spectral components and magnitude of the load current. If the quality metric reaches or exceeds a predefined threshold, indicating that the spectral components of the load current are rich enough to perform an EIS measurement (e.g., if the load current has sufficient signal components at multiple different frequencies or frequency ranges), then the charging circuit 132 can perform a satisfactory EIS measurement based on the load current. Thus, the charging circuit 132 performs an EIS measurement by detecting and recording the impedance of the battery 130 at multiple frequencies or frequency ranges present in the load current to generate an EIS measurement output of the battery 110.

[0092] If the quality metric is below the threshold, it indicates that the spectral components are not rich enough to perform an EIS measurement. For example, the load current may contain insufficient signal components at a minimum number or range of frequencies or frequency ranges, which may prevent the impedance of the battery from being detected at the minimum number or range of frequencies or frequency ranges. In such a case, the charging circuit 132 can defer performing the EIS measurement because any such measurement may produce inaccurate or unreliable results. Alternatively, the charging circuit 132 can control the current sink 136 (or another current-consuming device) to draw additional current from the battery 110 to increase the load current drawn by the load 120 such that the total spectral components of the combined current drawn from the battery 110 by the load 120 and the current sink 136 are sufficient to perform an accurate EIS measurement of the battery 110. A description of dynamically monitoring the load current of a system and increasing the load current using a controlled current sink is provided in U.S. Provisional Patent Application No. 63 / 415,413, filed on October 12, 2022, the content of which is incorporated herein by reference in its entirety.

[0093] As described above, the charging circuit 132 may be configured to receive or determine the battery SoC and / or SoH. This additional information may be combined with the EIS measurements generated by the charging circuit 132 based on the load current drawn by the load 120 from the battery 110 (and additional current drawn by the current sink 136 if necessary) to infer or otherwise determine the temperature of the battery.

[0094] Figures 3a to 3d is a graph showing example EIS measurement outputs of the battery at different states of charge (0%, 5%, 10%, and 20% respectively) and different temperature ranges. Each EIS measurement output includes the real part of the battery impedance (as shown on the x-axis in Figures 3a to 3d and the negative imaginary part of the battery impedance (as shown on the y-axis in Figures 3a to 3d ). Figures 3a to 3d Each individual trace in Figures 3a to 3d represents the EIS measurement output for different battery temperatures and directions of current flow, as indicated by the legend on each graph (where ch indicates current flowing into the battery for charging and dch indicates current flowing out of the battery for discharging). It can be clearly seen from the EIS measurement graphs in

[0095] that the EIS determination at a given frequency and temperature varies with the battery SoC.

[0096] One of ordinary skill in the art will understand that in other applications, being able to determine, estimate, or infer the temperature of a battery without using a discrete sensor array may be useful, for example, to detect potential damage or dangerous over-temperature conditions of the battery caused by, for example, excessive battery loading or battery damage. Accordingly, the present disclosure extends to stand-alone systems for determining battery temperature based on EIS (or EIS-like) measurements.

[0097] Figure 4Schematic diagram of a battery-powered electronic device including a system for estimating battery temperature. The battery-powered electronic device 400 can be, for example, a mobile phone, a tablet or laptop computer, a portable media player, a virtual reality (VR) or augmented reality (AR) headset, a portable gaming device, etc.

[0098] The battery-powered electronic device 400 includes a battery 410 that supplies electrical power to a load 420, and the load 420 can include one or more components or subsystems of the battery-powered electronic device 400, such as a processing subsystem, a display subsystem, an audio subsystem, a user input subsystem, etc.

[0099] The battery-powered electronic device 400 further includes a temperature estimation system 430, and may also include a current sink 432. The temperature estimation system 430 can be implemented as a single IC, which may also include the current sink 432 (if present). Alternatively, the current sink 432 (if present) can be implemented as a separate IC or discrete circuit.

[0100] The temperature estimation system 430 is configured to perform dynamic EIS (or EIS-like) measurements of the battery 410 in real time using the load current drawn from the battery as an effective EIS excitation signal, as described above with reference to Figure 1 FIG. 3, and estimate, infer, or otherwise determine the temperature of the battery 410 based on the measurement results (and optionally also based on additional information, such as the SoC and / or SoH of the battery 110).

[0101] Accordingly, the temperature estimation system 430 can include a voltage monitoring circuit 434 configured to monitor the voltage of the battery 410; a current monitoring circuit 436 configured to monitor the load current drawn from the battery 410 by the load 420; and a processing circuit 438 configured to perform EIS measurement results based on the monitored current. The current monitoring circuit 436 can be configured to detect the voltage across a current sensing resistor 440 in the current path between the battery 410 and the load 420.

[0102] The processing circuit 438 can be configured to determine a quality metric based on the spectral components and amplitude of the load current. If the quality metric reaches or exceeds a predefined threshold, indicating that the spectral components of the load current are rich enough to perform EIS measurements, for example, if the load current has sufficient signal components at multiple different frequencies or frequency ranges, the temperature estimation system 430 can perform satisfactory EIS measurements based on the load current.

[0103] If the quality metric is below a predefined threshold, the spectral components are not rich enough to perform an EIS measurement (e.g., the load current contains insufficient signal components in the minimum frequency range or frequency ranges, which may prevent the impedance of the battery from being detected in the minimum number or range of frequencies or frequency ranges), and the temperature estimation system 430 may defer performing the EIS measurement. Alternatively, the temperature estimation system 430 may control the current absorber 432 to draw additional current from the battery 410 to increase the load current drawn by the load 420 such that the total spectral components of the combined current drawn by the load 420 and the current absorber 432 from the battery 410 are sufficient to perform an accurate EIS measurement on the battery 410. Similarly, the applicant's U.S. Provisional Patent Application No. 63 / 415,413, filed on October 12, 2022, provides a description of dynamically monitoring the load current of the system and increasing the load current using a controlled current absorber, the content of which is incorporated herein by reference in its entirety.

[0104] The temperature estimation system 430 may be configured to receive or determine the battery SoC and / or SoH. This additional information may be combined with the results of the EIS measurement generated by the temperature estimation system 430 based on the load current drawn by the load 420 from the battery 410 (and, if necessary, the additional current drawn by the current absorber 432) to infer or otherwise determine the temperature of the battery 410.

[0105] The temperature estimation system 430 may store a set of reference EIS measurement outputs for different battery charge states and / or health states and temperatures.

[0106] When the temperature estimation system 430 has performed an EIS measurement on the battery 410 and has determined or received the battery SoC and / or SoH, the temperature estimation system 430 may compare the result of the EIS measurement with a relevant one of the stored reference EIS measurement outputs (i.e., the reference EIS measurement output stored at the battery SoC and / or SoH corresponding to the SoC and / or SoH received or determined by the temperature estimation system 430) to determine, estimate, or infer the battery temperature by identifying the reference EIS measurement output that most closely matches or corresponds to the result of the EIS measurement generated by the temperature estimation system 430.

[0107] Thus, the temperature estimation system 430 may estimate the temperature of the battery 410 without interrupting the operation of the electronic device 400 and without requiring a temperature sensor array.

[0108] The circuits described above with reference to the accompanying drawings may be incorporated in a host device such as a laptop, notebook, netbook or tablet computer, a gaming device such as a game console or a controller for a game console, a virtual reality (VR) or augmented reality (AR) device, a mobile phone, a portable audio player or some other portable device, or may be incorporated in an accessory device used in conjunction with a laptop, notebook, netbook or tablet computer, a gaming device, a VR or AR device, a mobile phone, a portable audio player or other portable device.

[0109] Those skilled in the art will recognize that some aspects of the above-described apparatus and methods may be embodied as processor control code, for example, on a non-volatile carrier medium such as a disk, a CD- or DVD-ROM, a programmed memory such as a read-only memory (firmware), or on a data carrier such as an optical or electrical signal carrier. For many applications, embodiments of the invention will be implemented on a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), or an FPGA (Field Programmable Gate Array). Thus, the code may include conventional program code or microcode, or code for setting or controlling an ASIC or FPGA, for example. The code may also include code for dynamically configuring a reconfigurable device such as a reprogrammable logic gate array. Similarly, the code may include code for a hardware description language such as Verilog TM or VHDL (Very High Speed Integrated Circuit Hardware Description Language). As will be understood by those skilled in the art, the code may be distributed among a plurality of coupled components that communicate with one another. In appropriate cases, code for running on a field (reprogrammable) programmable analog array or similar device to configure analog hardware may also be used to implement the embodiments.

[0110] Note that as used herein, the term module should be used to refer to a functional unit or block that can be implemented at least in part by dedicated hardware components such as custom-defined circuits and / or at least in part by one or more software processors or suitable code running on a suitable general-purpose processor, etc. A module itself may include other modules or functional units. A module may be provided by a plurality of components or sub-modules, and the components or sub-modules need not be co-located, but may be provided on different integrated circuits and / or run on different processors.

[0111] As used herein, where two or more elements are said to be "coupled" to each other, such term indicates that the two or more elements are in electrical or mechanical communication, whether directly or indirectly, with or without intervening elements, as applicable.

[0112] This disclosure covers all changes, substitutions, variations, alterations, and modifications to the exemplary embodiments herein that would be understood by a person of ordinary skill in the art. Similarly, where appropriate, the appended claims cover all changes, substitutions, variations, alterations, and modifications to the exemplary embodiments herein that would be understood by a person of ordinary skill in the art. Additionally, references in the appended claims to a device or system or a component of a device or system that is adapted to, arranged to, capable of, configured to, enabled to, operably or operationally perform a particular function cover such device, system, or component, whether or not that or the particular function is activated, turned on, or unlocked, so long as the device, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operational. Accordingly, the systems, devices, and methods described herein may be modified, added to, or omitted without departing from the scope of this disclosure. For example, components of the systems and devices may be integrated or separated. Additionally, operations of the systems and devices disclosed herein may be performed by more, fewer, or other components, and the methods described may include more, fewer, or other steps. Further, the steps may be performed in any suitable order. As used in this document, "each" refers to each member of a set or each member of a subset of a set.

[0113] Although the exemplary embodiments are illustrated in the drawings and described below, the principles of this disclosure may be implemented using any number of techniques, whether currently known or not. This disclosure should not in any way be limited to the exemplary embodiments and techniques shown in the drawings and described above.

[0114] Unless otherwise explicitly stated, the items depicted in the drawings are not necessarily drawn to scale.

[0115] All of the example and conditional language recited herein is intended for pedagogical purposes to aid the reader in understanding the disclosure and the concepts contributed by the inventors to further the art, and is to be construed as not being limited to such specifically recited examples and conditions. Although the embodiments of this disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of this disclosure.

[0116] Although specific advantages have been enumerated above, various embodiments may include some or all of the enumerated advantages, or may not include the enumerated advantages. Additionally, other technical advantages may become apparent to a person of ordinary skill in the art after reviewing the foregoing drawings and description.

[0117] It should be noted that the above-described embodiments illustrate rather than limit the present invention, and those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. The word "comprising" does not exclude the presence of elements or steps other than those listed in the claims, "a" or "an" does not exclude a plurality, and a single feature or other unit may perform the functions of several units recited in the claims. Any reference signs or labels in the claims should not be construed as limiting their scope.

Claims

1. A system for controlling battery charging, the system comprises: a charging circuit for supplying a charging current or voltage to the battery, wherein the charging circuit is configured to periodically detect an impedance of the battery and control the charging current or voltage based on the detected impedance.

2. The system according to claim 1, further comprising a heating arrangement for heating the battery, wherein the charging circuit is configured to control the heating arrangement based on the detected impedance of the battery to maintain the temperature of the battery within a predefined charging range.

3. The system according to claim 1 or claim 2, wherein the charging circuit is configured to detect a voltage and a current of the battery and detect the impedance based on the detected voltage and current.

4. The system according to any one of the preceding claims, wherein the charging circuit is configured to infer a temperature of the battery based on the detected impedance.

5. The system according to claim 4, further comprising a heating arrangement for heating the battery, wherein the charging circuit is configured to control the heating arrangement based on the inferred temperature of the battery.

6. The system according to claim 5, wherein the charging circuit is configured to control the heating arrangement based on the inferred temperature of the battery and one or more of the following: a state of charge (SoC) of the battery; a state of health (SoH) of the battery.

7. The system according to claim 4, wherein the charging circuit is configured to control a charging current supplied to the battery based on the inferred temperature of the battery.

8. The system according to claim 7, wherein the charging circuit is configured to control the charging current supplied to the battery based on the inferred temperature of the battery and one or more of the following: a state of charge (SoC) of the battery; a state of health (SoH) of the battery.

9. The system according to claim 4, wherein the charging circuit is configured to detect the impedance of the battery at a plurality of different frequencies or frequency ranges and infer the temperature of the battery based on the impedance detected at the plurality of different frequencies or frequency ranges.

10. The system according to claim 9, wherein the charging circuit is configured to monitor a load current drawn from the battery and detect the impedance of the battery at the plurality of different frequencies or frequency ranges based on the monitored load current to generate an electrochemical impedance spectroscopy (EIS) measurement output of the battery.

11. The system according to claim 10, wherein the charging circuit is configured to control a current-consuming device to draw additional current from the battery if a frequency component of the monitored load current is insufficient to detect the impedance of the battery at a minimum number of different frequencies or frequency ranges.

12. The system according to claim 11, wherein the charging circuit is configured to determine a quality metric of the load current based on spectral components and amplitude of the load current, and if the quality metric is below a predefined threshold, control the current consuming device to draw the additional current from the battery.

13. The system according to any one of claims 10 - 12, wherein the charging circuit is configured to compare the EIS measurement output generated by the charging circuit for the battery with a set of reference EIS measurement outputs to infer the temperature of the battery.

14. The system according to any one of the preceding claims, wherein the system is configured to: receive a temperature measurement of the host device when the host device incorporating the system is inactive or in a sleep or idle operating mode; detect the impedance of the battery when the host device is inactive or in the sleep or idle operating mode; and calibrate the system using the received temperature measurement and the detected impedance when the host device is inactive or in the sleep or idle operating mode.

15. The system according to any one of claims 2 - 14, wherein the heating arrangement includes a coil for inductive power transfer between a host device incorporating the system and another device.

16. The system according to any one of claims 2 - 14, wherein the heating arrangement includes an array of resistive elements disposed near the battery when the system is in use.

17. The system according to any one of claims 2 - 14, wherein the heating arrangement includes a circuit configured to supply a signal or waveform to the battery to cause a temperature change of the battery by varying resistive losses in the battery.

18. The system according to claim 17, wherein the circuit is configured to supply a time - varying current or voltage signal to the battery.

19. The system according to any one of claims 2 - 18, wherein when the system is connected to a power source external to the system, the charging circuit is operative to: detect the impedance of the battery; determine the temperature of the battery based on the detected impedance; and if the determined temperature of the battery is below a predetermined battery temperature range, output a heating control signal to cause the heating arrangement to heat the battery.

20. The system according to claim 19, wherein the charging circuit is further operative to delay charging of the battery until the temperature of the battery reaches the predetermined battery temperature range.

21. A system for controlling battery charging, the system comprising: a charging circuit configured to: detect the impedance of the battery; infer the temperature of the battery based on the detected impedance of the battery; supply a charging current to the battery, wherein the charging current is based on the inferred temperature of the battery.

22. A system for controlling battery charging, the system comprising: a heating arrangement for heating the battery; A charging circuit configured to detect a temperature of the battery and control the heating arrangement based on the detected temperature to maintain an impedance of the battery within a predefined impedance range for charging.

23. A system for estimating a temperature of a battery, wherein the system is configured to: Monitor a load current drawn from the battery; Detect an impedance of the battery at a plurality of different frequencies or frequency ranges based on the monitored load current to generate an Electrochemical Impedance Spectroscopy (EIS) measurement output of the battery; and Estimate the temperature of the battery based on the EIS measurement output.

24. The system of claim 23, wherein the system is further configured to receive a State of Charge (SoC) and / or a State of Health (SoH) of the battery and estimate the temperature of the battery based on a combination of the EIS measurement output and the SoC and / or SoH.

25. The system of claim 24, wherein the system is configured to compare the EIS measurement output with a set of reference EIS measurement outputs to infer the temperature of the battery.

26. The system of claim 24 or claim 25, wherein the system is further configured to: Receive a State of Charge (SoC) and / or a State of Health (SoH) of the battery; Select at least one reference EIS measurement output based on the received SoC and / or SoH; and Estimate the temperature of the battery based on the selected at least one reference EIS measurement output and the EIS measurement output generated by the system.

27. The system of any one of claims 24-26, wherein the system is configured to control a current consuming device to draw additional current from the battery if a frequency component of the monitored load current is insufficient to detect the impedance of the battery at a minimum number of different frequencies or frequency ranges.

28. The system of claim 27, wherein the system is configured to determine a quality metric of the load current based on a spectral component and an amplitude of the load current and control the current consuming device to draw the additional current from the battery if the quality metric is below a predefined threshold.

29. The system of any one of claims 23-28, wherein the system is configured to: Receive a temperature measurement of the host device when the host device including the system is inactive or in a sleep or idle operating mode; Detect the impedance of the battery when the host device is inactive or in the sleep or idle operating mode; and And Calibrate the system using the received temperature measurement and the detected impedance when the host device is inactive or in the sleep or idle operating mode.

30. A system for controlling battery charging, the system Comprises: A charging circuit for supplying a charging current to the battery; And A heating arrangement for heating the battery, The charging circuit is configured to detect an impedance of the battery and to control the heating arrangement based on the detected impedance to maintain the temperature of the battery within a predefined temperature range for charging.

31. An integrated circuit comprising the system according to any one of the preceding claims.

32. A host device comprising the system according to any one of the preceding claims.

33. The host device according to claim 32, wherein the host device comprises a laptop, notebook, netbook or tablet computer, a gaming device, a game console, a controller for a game console, a virtual reality (VR) or augmented reality (AR) device, a mobile phone, a portable audio player, a portable device, an accessory device for use with a laptop, notebook, netbook or tablet computer, a gaming device, a game console, a VR or AR device, a mobile phone, a portable audio player or other portable device.

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