Battery management circuit, method and system, chip and electronic equipment

Abstract

The embodiment of the invention provides a battery management circuit, method, system, chip and electronic equipment, the battery management circuit is used for controlling a plurality of battery units, and the battery management circuit comprises an electrochemical impedance measurement module which is used for measuring the electrochemical impedance of the plurality of battery units in a preset frequency range; and the battery equalization module is used for carrying out electric quantity equalization on the plurality of battery units according to the electrochemical impedance of the plurality of battery units in the preset frequency range. According to the invention, aiming at different aging conditions of the battery, attenuation control can be effectively carried out, and the health degree of the battery is ensured.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and specifically to a battery management circuit, method, system, chip, and electronic device. Background Art

[0002] At present, due to the differences in battery production and use processes, each battery naturally has inconsistency problems, such as battery full charge capacity, battery remaining capacity, battery internal resistance, etc. The inconsistency of multiple batteries leads to the problem of reduced battery pack performance. Summary of the Invention

[0003] In view of the above problems, the embodiments of the present application provide a battery management circuit, method, system, chip and electronic device to solve the above technical problems.

[0004] In a first aspect, an embodiment of the present application provides a battery management circuit for controlling multiple battery cells, including:

[0005] An electrochemical impedance measurement module is used to measure the electrochemical impedance of multiple battery cells within a preset frequency range;

[0006] The battery balancing module is used to balance the charge of multiple battery cells according to the electrochemical impedance of the multiple battery cells within a preset frequency range.

[0007] In a second aspect, the present application provides a battery management method for managing multiple battery cells, comprising:

[0008] measuring the electrochemical impedance of the plurality of battery cells within a preset frequency range;

[0009] The multiple battery cells are evenly discharged according to the electrochemical impedances of the multiple battery cells within a preset frequency range.

[0010] In a third aspect, the present application provides a battery management system, comprising the above-mentioned battery management circuit.

[0011] In a fourth aspect, an embodiment of the present application further provides a chip comprising the above-mentioned battery management circuit.

[0012] In a fifth aspect, an embodiment of the present application further provides an electronic device comprising the above-mentioned chip or battery management system.

[0013] In an embodiment of the present application, the battery balancing module can balance the charge of multiple battery cells based on the electrochemical impedance of the multiple battery cells within a preset frequency range. Since the electrochemical impedance of the battery cells within the preset frequency range reflects the characteristics of the battery cells, the electrochemical impedance of the multiple battery cells within the preset frequency range can indicate whether the multiple battery cells are consistent. Therefore, the battery balancing module balances the charge of the multiple battery cells based on the electrochemical impedance of the multiple battery cells within the preset frequency range, thereby effectively controlling the attenuation of the different aging conditions of the batteries and ensuring the health of the batteries.

[0014] These and other aspects of the present application will become more readily apparent from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 A schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0017] Figure 2 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0018] Figure 3 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0019] Figure 4 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0020] Figure 5 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0021] Figure 6 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0022] Figure 7 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0023] Figure 8 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0024] Figure 9 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0025] Figure 10 Another schematic diagram of a battery management circuit in an embodiment of the present application is shown.

[0026] Figure 11 A flow chart of a battery management method in an embodiment of the present application is shown.

[0027] Among them, 1 battery unit, 100 battery management circuit, 10 electrochemical impedance measurement module, 11 excitation unit, 12 measurement unit, 121 signal amplifier, 122 analog-to-digital converter, 123 impedance calculation circuit, 20 battery balancing module;

[0028] The excitation balance switch M0, the first switch S1, the second switch S2, the third switch S3, the fourth switches S41-S4n, the first capacitor C1, and the second capacitor C2. DETAILED DESCRIPTION

[0029] The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0030] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0031] In the embodiments of the present application, it should be noted that, in this document, relational terms such as first and second, etc., are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0032] Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0033] In the description of the embodiments of this application, words such as "example" or "for example" are used to indicate an example, illustration, or description. Any embodiment or design described as "for example" or "for example" in the embodiments of this application is not to be construed as being preferred or having more advantages than another embodiment or design. The use of words such as "example" or "for example" is intended to clearly present relative concepts.

[0034] In addition, in the embodiments of the present application, "plurality" refers to two or more. In view of this, in the embodiments of the present application, "plurality" can also be understood as "at least two". "At least one" can be understood as one or more, for example, one, two, or more. For example, "including at least one" means including one, two, or more, and does not limit which ones are included. For example, "including at least one of A, B, and C" means including A, B, C, A and B, A and C, B and C, or A, B, and C.

[0035] It should be noted that in the embodiments of the present application, "and / or" describes the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / ", unless otherwise specified, generally indicates that the associated objects are in an "or" relationship.

[0036] It should be noted that in the embodiments of the present application, "connection" can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be either a direct connection between A and B or an indirect connection between A and B through one or more other electrical components.

[0037] Currently, batteries exhibit inconsistencies in terms of full charge capacity, remaining capacity, and internal resistance. These inconsistencies can impact battery life and service life. For example, during charging, a battery with a higher voltage may trigger overvoltage protection and halt charging, leaving the other batteries with lower voltages partially charged. Another example is during discharge, where a battery with a lower discharge voltage may trigger undervoltage protection and halt discharge, while the other batteries with higher voltages still have plenty of charge. Furthermore, because inconsistent batteries are frequently subject to overvoltage and undervoltage protection during charging and discharging, this can impact the lifespan of that battery and may even affect battery safety.

[0038] To this end, the present application provides a battery management circuit, method, system, chip and electronic device, which are described in detail below.

[0039] First, see Figure 1 , Figure 1A schematic diagram of a battery management circuit 100 in an embodiment of the present application is shown, wherein the battery management circuit 100 includes an electrochemical impedance measurement module 10 and a battery balancing module 20 .

[0040] Specifically, the electrochemical impedance measurement module 10 is used to measure the electrochemical impedance of multiple battery cells 1 within a preset frequency range (e.g., 0.01 Hz to 10 kHz). Generally, the electrochemical impedance measurement module 10 can output excitation signals of different frequencies to the same battery cell 1. Under the excitation of excitation signals of different frequencies, the battery cell 1 can generate response signals of different frequencies. After measuring the response signals of different frequencies, the electrochemical impedance of the battery cell 1 at different frequencies can be calculated. Therefore, the electrochemical impedances at different frequencies can be combined to form the electrochemical impedance of a battery cell 1 within a preset frequency range (i.e., electrochemical impedance spectroscopy, abbreviated as EIS).

[0041] In some embodiments of the present application, the electrochemical impedance measurement module 10 can excite the battery cell 1 using a constant current method, that is, the current flowing through the battery is known, and thus the electrochemical impedance of the battery can be calculated by simply measuring the voltage across the battery. In some embodiments of the present application, the electrochemical impedance measurement module 10 can excite the battery cell 1 using a constant voltage method, that is, the voltage of the battery cell 1 is known, and thus the electrochemical impedance of the battery can be calculated by simply measuring the current flowing through the battery.

[0042] For example, assuming that the electrochemical impedance measurement module 10 excites the battery cell 1 with a constant current and the current flowing through the cell is known, after measuring the voltage across the battery, the impedance at the corresponding frequency can be calculated using the following formula:

[0043]

[0044] Where Z(fn) is the impedance of battery cell 1 at frequency fn, V1(fn) is the effective amplitude of the battery voltage at the corresponding frequency fn, V2(fn) is the effective amplitude of the battery current at the corresponding frequency fn, R is the real part of the complex impedance, and X is the imaginary part of the complex impedance.

[0045] In some embodiments of the present application, the electrochemical impedance measurement module 10 can serially measure the electrochemical impedance of multiple battery cells 1 within a preset frequency range. For example, assuming that the electrochemical impedance measurement module 10 can only output one excitation signal and measure one response signal, the electrochemical impedance measurement module 10 can only measure one battery cell 1 at any time. Figure 1In the embodiment, the electrochemical impedance measurement module 10 may first measure the electrochemical impedance of the battery cell 1 with a serial number of 1 within a preset frequency range, and then measure the electrochemical impedance of the battery cell 1 with a serial number of 2 within the preset frequency range, and so on.

[0046] In some embodiments of the present application, the electrochemical impedance measurement module 10 can measure the electrochemical impedance of multiple battery cells 1 in parallel within a preset frequency range. For example, assuming that the electrochemical impedance measurement module 10 can simultaneously output multiple excitation signals and measure multiple response signals, the electrochemical impedance measurement module 10 can measure multiple battery cells 1 at any time. Figure 1 In the embodiment, the electrochemical impedance measurement module 10 can simultaneously measure the electrochemical impedance of the battery cells 1 with sequence number 1 and sequence number 2 within a preset frequency range, or the electrochemical impedance measurement module 10 can simultaneously measure the electrochemical impedance of all battery cells 1 within a preset frequency range.

[0047] It is understandable that, under normal circumstances, exciting a battery cell 1 once (i.e., inputting an excitation signal of a certain frequency once) can usually measure the electrochemical impedance of the battery cell 1 at the frequency once. Therefore, to obtain the electrochemical impedance of the battery cell 1 in a preset frequency range, it is usually necessary to excite the battery cell 1 multiple times, but it is not limited to this. For example, in some possible embodiments, an excitation signal may include multiple frequencies. After obtaining the amplitude of the response signal at each measurement frequency point through a bandpass filter and an analog-to-digital converter, the electrochemical impedance of the battery cell 1 at multiple frequency points can also be measured by excitation once.

[0048] The battery balancing module 20 can balance the power of the multiple battery cells 1 so that the power of the multiple battery cells 1 tends to be consistent.

[0049] In some embodiments of the present application, the battery balancing module 20 can balance the battery charge by controlling the discharge amount of different battery cells 1. For example, Figure 1 , discharge the battery cell 1 with sequence number 1, the battery cell 1 with sequence number 2, ... the battery cell 1 with sequence number n to different degrees, thereby balancing the power of multiple battery cells 1. In some embodiments of the present application, the battery balancing module 20 can balance the power by controlling the charge amount of different battery cells 1, for example, see Figure 1 , the battery cell 1 with a serial number of 1, the battery cell 1 with a serial number of 2, ... the battery cell 1 with a serial number of n are charged to different degrees, thereby balancing the power of the multiple battery cells 1.

[0050] In some embodiments of the present application, the battery balancing module 20 can sequentially control the power of multiple battery cells 1 to achieve power balancing. For example, see Figure 1, balancing the battery cell 1 with sequence number 1, the battery cell 1 with sequence number 2, ..., and the battery cell 1 with sequence number n in sequence. In some embodiments of the present application, the battery balancing module 20 can simultaneously control the charge of multiple battery cells 1 to achieve charge balancing. For example, the battery balancing module 20 can simultaneously input control signals to multiple battery cells 1 to simultaneously balance the charge of the battery cell 1 with sequence number 1, the battery cell 1 with sequence number 2, ..., and the battery cell 1 with sequence number n.

[0051] In the embodiment of the present application, the battery balancing module 20 can balance the charge of the multiple battery cells 1 according to the electrochemical impedance of the multiple battery cells 1 within a preset frequency range.

[0052] It should be noted that the electrochemical impedance of the battery cell 1 within the preset frequency range reflects the characteristics of the battery cell 1. Therefore, the electrochemical impedance of multiple battery cells 1 within the preset frequency range can indicate whether the multiple battery cells 1 are consistent. Then, the battery balancing module 20 balances the battery cells 1 according to the electrochemical impedance of the multiple battery cells 1 within the preset frequency range, and can effectively control the attenuation of the different aging conditions of the battery, thereby ensuring the health of the battery.

[0053] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively correlated with the average electrochemical impedance of the battery cell 1 within a preset frequency range. For example, see Figure 2 , Figure 2 A schematic diagram of the electrochemical impedance spectrum of each battery cell 1 in the embodiment of the present application is shown. After obtaining the electrochemical impedance of each battery cell 1 within a preset frequency range, the Figure 2 The average electrochemical impedance of each battery cell 1 within a preset frequency range is calculated, and then the balanced discharge capacity of the battery cell 1 is determined based on the average electrochemical impedance. The larger the average electrochemical impedance, the greater the balanced discharge capacity of the battery cell 1. Conversely, the smaller the average electrochemical impedance, the smaller the balanced discharge capacity of the battery cell 1.

[0054] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively correlated with the peak-to-peak value of the electrochemical impedance of the battery cell 1 within a preset frequency range. For example, see Figure 2 After obtaining the electrochemical impedance of each battery cell 1 within the preset frequency range, the Figure 2The electrochemical impedance peak-to-peak value (i.e., the difference between the maximum electrochemical impedance and the minimum electrochemical impedance) of each battery cell 1 within a preset frequency range is calculated, and then the balanced discharge capacity of the battery cell 1 is determined based on the electrochemical impedance peak-to-peak value. The larger the electrochemical impedance peak-to-peak value, the greater the balanced discharge capacity of the battery cell 1. Conversely, the smaller the electrochemical impedance peak-to-peak value, the smaller the balanced discharge capacity of the battery cell 1.

[0055] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively correlated with the RMS value of the electrochemical impedance of the battery cell 1 within a preset frequency range. For example, see Figure 2 After obtaining the electrochemical impedance of each battery cell 1 within the preset frequency range, the Figure 2 The electrochemical impedance root mean square value of each battery cell 1 within a preset frequency range is calculated, and then the balanced discharge capacity of the battery cell 1 is determined based on the electrochemical impedance root mean square value. The larger the electrochemical impedance root mean square value, the greater the balanced discharge capacity of the battery cell 1. Conversely, the smaller the electrochemical impedance root mean square value, the smaller the balanced discharge capacity of the battery cell 1.

[0056] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively or negatively correlated with the average electrochemical impedance of the battery cell 1 within a set frequency range, and the set frequency range is within a preset frequency range. For example, see Figure 3 , Figure 3 Another schematic diagram of the electrochemical impedance spectrum of each battery cell 1 in the embodiment of the present application is shown. After obtaining the electrochemical impedance of each battery cell 1 within the set frequency range, the Figure 3 The average electrochemical impedance of each battery cell 1 within the set frequency range is calculated, and then the balanced discharge capacity of the battery cell 1 is determined based on the average electrochemical impedance. The larger the average electrochemical impedance, the greater the balanced discharge capacity of the battery cell 1. Conversely, the smaller the average electrochemical impedance, the smaller the balanced discharge capacity of the battery cell 1.

[0057] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively or negatively correlated with the peak-to-peak value of the electrochemical impedance of the battery cell 1 within a set frequency range, and the set frequency range is within a preset frequency range. For example, see Figure 3 After obtaining the electrochemical impedance of each battery cell 1 within the set frequency range, the Figure 3 The peak-to-peak value of the electrochemical impedance of each battery cell 1 within the set frequency range is calculated, and then the balanced discharge capacity of the battery cell 1 is determined based on the peak-to-peak value of the electrochemical impedance. The larger the peak-to-peak value of the electrochemical impedance, the greater the balanced discharge capacity of the battery cell 1. Conversely, the smaller the peak-to-peak value of the electrochemical impedance, the smaller the balanced discharge capacity of the battery cell 1.

[0058] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively or negatively correlated with the electrochemical impedance root mean square value of the battery cell 1 within a set frequency range, and the set frequency range is within a preset frequency range. For example, see Figure 3 After obtaining the electrochemical impedance of each battery cell 1 within the set frequency range, the Figure 3 The electrochemical impedance root mean square value of each battery cell 1 within the set frequency range is calculated, and then the balanced discharge capacity of the battery cell 1 is determined based on the electrochemical impedance root mean square value. The larger the electrochemical impedance root mean square value, the greater the balanced discharge capacity of the battery cell 1. Conversely, the smaller the electrochemical impedance root mean square value, the smaller the balanced discharge capacity of the battery cell 1.

[0059] In some embodiments of the present application, each battery cell 1 includes an excitation balancing switch M0; when the battery management circuit 100 measures the electrochemical impedance of the battery cell 1 within a preset frequency range, the electrochemical impedance measurement module 10 controls the excitation balancing switch M0; when the battery management circuit 100 controls the battery cell 1 to perform balanced discharge, the battery balancing module 20 controls the excitation balancing switch M0.

[0060] For example, see Figure 4 , Figure 4 Another schematic diagram of a battery management circuit 100 according to an embodiment of the present application is shown. Each battery cell 1 includes a battery cell, a resistor R0, and an excitation balancing switch M0. When the battery management circuit 100 measures the electrochemical impedance of the battery cell 1 within a preset frequency range, the electrochemical impedance measurement module 10 controls the excitation balancing switch M0, causing it to conduct at the excitation frequency. At this point, the battery cell generates a response signal corresponding to the excitation frequency, allowing the electrochemical impedance of the battery cell 1 at the excitation frequency to be measured. Furthermore, when the battery management circuit 100 controls the battery cell 1 for balanced discharge, the battery balancing module 20 controls the excitation balancing switch M0 to conduct, causing the battery cell corresponding to the battery cell 1 to discharge, thereby achieving a charge balancing process for the battery cell 1.

[0061] It is understandable that, during the charge balancing control process of the battery unit 1 , the excitation balancing switch M0 may remain in the on state or be intermittently turned on, and this application does not impose any specific limitation.

[0062] In some embodiments of this application, see Figure 5 , Figure 5Another schematic diagram of the battery management circuit 100 in an embodiment of the present application is shown, wherein the battery management circuit 100 further includes a first switch S1 and a second switch S2; a first end of the first switch S1 is connected to the electrochemical impedance measurement module 10, and a second end of the first switch S1 is connected to the control end of the excitation balancing switch M0; a first end of the second switch S2 is connected to the battery balancing module 20, and a second end of the second switch S2 is connected to the control end of the excitation balancing switch M0.

[0063] It should be noted that when the battery management circuit 100 measures the electrochemical impedance of the battery cell 1 within a preset frequency range, the first switch S1 is closed and the second switch S2 is opened, so that the electrochemical impedance measurement module 10 controls the excitation balancing switch M0 to perform electrochemical impedance measurement; and when the battery management circuit 100 controls the battery cell 1 to perform balanced discharge, the first switch S1 is opened and the second switch S2 is closed, so that the battery balancing module 20 controls the excitation balancing switch M0 to perform battery balancing.

[0064] In some embodiments of this application, see Figure 6 , Figure 6 Another schematic diagram of a battery management circuit 100 in an embodiment of the present application is shown, wherein the electrochemical impedance measurement module 10 includes an excitation unit 11 and a measurement unit 12 .

[0065] Specifically, the excitation unit 11 can input an excitation signal ES to the battery cell 1, so that the excitation battery cell 1 is excited by the excitation signal ES and outputs a response signal RS. Generally, the excitation unit 11 can output excitation signals ES of different frequencies. Under the excitation of the excitation signals ES of different frequencies, the battery cell 1 can generate response signals RS of different frequencies. After the measurement unit 12 measures the response signals RS of different frequencies, the electrochemical impedance of the battery cell 1 at different frequencies can be calculated. Therefore, the electrochemical impedances at different frequencies can be combined to form an electrochemical impedance spectrum of the battery cell 1 within a preset frequency range.

[0066] In some embodiments of the present application, the excitation signal ES may be a signal for controlling the battery unit 1, for example, Figure 6 In the embodiment, the excitation signal ES controls the excitation balancing switch M0 to conduct, so that a current is generated in the loop where the battery cell is located. At this time, the voltage of the battery cell and / or the current flowing through the resistor R0 can be used as the response signal RS. After the measurement unit 12 measures the voltage of the battery cell and / or the current flowing through the resistor R0, the electrochemical impedance of the battery cell can be calculated.

[0067] It can be understood that when the excitation unit 11 excites the battery cell 1 in a constant current manner, the current flowing through the resistor R0 is known, so the measurement unit 12 only needs to measure the voltage across the battery cell to calculate the electrochemical impedance of the battery cell; similarly, when the excitation unit 11 excites the battery cell 1 in a constant voltage manner, the voltage across the battery cell is known, so the electrochemical impedance of the battery cell only needs to be measured.

[0068] It should be pointed out that the implementation method of the excitation unit 11 to excite the battery cell 1 is not limited to this. For example, in some possible embodiments, the excitation signal ES may also be a voltage or current signal input to the battery cell 1. The battery cell 1 may generate a current signal as a response signal RS after the voltage signal is input, or the battery cell 1 may generate a current signal as a current signal after the current signal is input. After the measuring unit 12 measures the voltage response signal RS or the current response signal RS of the battery cell 1, the electrochemical impedance of the battery cell 1 may be calculated in combination with the excitation signal ES.

[0069] In some embodiments of the present application, the excitation unit 11 can output the excitation signal ES through signal simulation. For example, after determining the AC voltage value of the excitation signal ES in the time domain, the excitation unit 11 outputs the analog voltage in a time sequence through a digital-to-analog converter, thereby achieving the purpose of simulating the output of the excitation signal ES. In some embodiments of the present application, the excitation unit 11 can simulate the output of the excitation signal ES through an oscillator, and generate the excitation signal ES of the corresponding frequency by controlling the oscillation frequency of the oscillator. For example, the excitation signal ES can be, but is not limited to, an AC signal such as a sine signal, a cosine signal, or a square wave signal.

[0070] As an example, the excitation unit 11 may include a DDS signal generator, a digital-to-analog converter, a low-pass filter, and a MOS tube driving circuit. The digital-to-analog converter converts the digital signal output by the DDS signal generator into an analog voltage in a timing sequence and forms a sinusoidal AC voltage signal or a square wave AC voltage signal. After filtering by the low-pass filter and the MOS tube driving circuit, the excitation signal ES for controlling the excitation balancing switch M0 in the excitation battery unit 1 can be output.

[0071] The measurement unit 12 can measure the amplitude of the response signal RS to determine the electrochemical impedance of the battery cell 1 at the corresponding frequency based on the response signal RS at the corresponding frequency. In some embodiments of the present application, the measurement unit 12 can include an analog-to-digital converter and an impedance calculation circuit. The analog-to-digital converter can convert the response signal RS into a digital signal. The impedance calculation circuit can perform a Fourier transform on the digital signal output by the analog-to-digital converter and obtain a frequency domain signal corresponding to the response signal RS, so as to calculate the electrical impedance value of the battery cell 1 at the corresponding frequency based on the frequency domain signal.

[0072] Exemplarily, the analog-to-digital converter may be, but is not limited to, a hybrid analog-to-digital converter consisting of one or more of a successive approximation ADC (SAR ADC), a Sigma-Delta ADC (SD ADC), and a pipeline ADC (Pipeline ADC).

[0073] In some embodiments of the present application, see Figure 7 , Figure 7 Another schematic diagram of the battery management circuit 100 in an embodiment of the present application is shown, wherein the electrochemical impedance measurement module 10 further includes a plurality of first capacitors C1 and a plurality of second capacitors C2, the first capacitors C1 corresponding one-to-one to the battery cells 1, and the second capacitors C2 corresponding one-to-one to the battery cells 1; the first end of the first capacitor C1 is coupled to the first end of the corresponding battery cell 1, and the second end of the first capacitor C1 is connected to the measurement unit 12; the first end of the second capacitor C2 is coupled to the second end of the corresponding battery cell 1, and the second end of the second capacitor C2 is connected to the measurement unit 12.

[0074] It should be noted that, in the process of the electrochemical impedance measurement module 10 measuring the electrochemical impedance of the battery cell 1, the second end of the first capacitor C1 and the second end of the second capacitor C2 can isolate the DC component and output an AC signal. Therefore, the measuring unit 12 can use the voltage difference △V between the second end of the first capacitor C1 and the second end of the second capacitor C2 as the response signal RS, thereby determining the electrochemical impedance of the battery cell 1 according to the voltage difference △V between the second end of the first capacitor C1 and the second end of the second capacitor C2. Since the second terminal voltage of the first capacitor C1 and the second terminal voltage of the second capacitor C2 do not contain a DC component but only an AC component, the proportion of useful signals in the response signal RS can be increased, that is, the signal-to-noise ratio of the response signal RS is improved, which is ultimately beneficial to improving the electrochemical impedance measurement accuracy of the battery cell 1.

[0075] In some embodiments of this application, see Figure 8 , Figure 8 Another schematic diagram of the battery management circuit 100 in an embodiment of the present application is shown, wherein the measuring unit 12 includes a signal amplifier 121, an analog-to-digital converter 122 and an impedance calculation circuit 123. The signal amplification circuit can amplify the response signal RS to improve the signal-to-noise ratio of the response signal RS, and the analog-to-digital converter 122 can convert the response signal RS into a digital signal. The impedance calculation circuit 123 can perform a Fourier transform on the digital signal output by the analog-to-digital converter 122 and obtain a frequency domain signal corresponding to the response signal RS, so as to calculate the electrical impedance value of the battery cell 1 at the corresponding frequency based on the frequency domain signal.

[0076] For example, the signal amplifier 121 may be, but is not limited to, a programmable gain amplifier (PGA) with a capacitor architecture or a programmable gain amplifier with a resistor architecture.

[0077] In some embodiments of the present application, for example, for an embodiment in which the measuring unit 12 includes a signal amplifier, see Figure 9 , Figure 9 Another schematic diagram of the battery management circuit 100 in an embodiment of the present application is shown, wherein the electrochemical impedance measurement module 10 includes a signal amplifier 121 and an analog-to-digital converter 122, and the battery management circuit 100 also includes a third switch S3 and fourth switches S41 to S4n; the first end of the third switch S3 is connected to the signal amplifier 121, and the second end of the third switch S3 is connected to the analog-to-digital converter 122; the first ends of the fourth switches S41 to S4n are connected to the battery cells 1 to n, and the second ends of the fourth switches S41 to S4n are connected to the analog-to-digital converter 122.

[0078] It should be noted that the signal amplifier 121 is configured to amplify the response signal RS output by the battery cell 1 during the process of the electrochemical impedance measurement module 10 measuring the electrochemical impedance of the battery cell 1. When the battery management circuit 100 measures the electrochemical impedance of the battery cell 1 within a preset frequency range, the third switch S3 is closed and the fourth switches S41 to S4n are opened, so that the analog-to-digital converter 122 can measure the amplified signal corresponding to the response signal RS output by the signal amplifier 121. When the battery management circuit 100 controls the battery cell 1 to perform balanced discharge, the third switch S3 is opened and the fourth switches S41 to S4n are closed. At this time, the analog-to-digital converter 122 can measure the charge of the battery cell 1, so that the battery balancing module 20 can control the excitation balancing switch M0 for charge balancing based on the battery charge and the electrochemical impedance spectrum.

[0079] It can be seen that in the above embodiment, the cell balancing module 20 reuses the analog-to-digital converter 122 of the electrochemical impedance measurement module 10. Therefore, there is no need to separately provide the cell balancing module 20 with an analog-to-digital converter for measuring battery charge, which helps to reduce the circuit board and cost of the battery management circuit 100.

[0080] In some embodiments of this application, see Figure 10 , Figure 10Another schematic diagram of the battery management circuit 100 in an embodiment of the present application is shown, wherein the battery balancing module 20 includes a balancing control unit 21 and a discharge drive unit 22; the balancing control unit 21 is used to output a discharge control signal to the discharge drive unit 22 based on the electrochemical impedance and battery capacity of each battery cell 1 within a preset frequency range, and the discharge drive unit 22 is used to output a discharge drive signal based on the discharge control signal, so as to drive the battery cells 1 to perform balanced discharge through the discharge drive signal.

[0081] Specifically, in Figure 10 The balancing control unit 21 is connected to the analog-to-digital converter 122, and the balancing control unit 21 is also connected to the impedance calculation circuit 123. After the impedance calculation circuit 123 calculates the electrochemical impedance of each battery cell 1 within a preset frequency range, the third switch S3 is opened and the fourth switches S41 to S4n are closed. The analog-to-digital converter 122 measures the battery capacity of each battery cell 1 and forwards it to the balancing control unit 21. Therefore, the balancing control unit 21 can output a discharge control signal based on the battery capacity of the battery cell and the electrochemical impedance within the preset frequency range, so that the discharge drive unit 22 outputs a discharge drive signal according to the discharge control signal to perform balanced discharge on the battery cells 1.

[0082] For example, taking the example that the balanced discharge capacity of each battery cell 1 is positively correlated with the average electrochemical impedance of the battery cell 1 within a preset frequency range, the balanced discharge capacity of each battery cell 1 can be calculated according to the following formula:

[0083] Q=(BL-BL_Avg)*k1+R_Avg*k2

[0084] Among them, BL is the current battery cell charge, BL_Avg is the average charge of all battery cells, R_Avg is the average electrochemical impedance of the current battery cell, and k1 and k2 are parameters determined by testing a specific type of battery.

[0085] It can be seen that after the balancing control unit 21 calculates the balanced discharge capacity of each battery cell 1 based on the battery capacity of the battery cell and the electrochemical impedance within the preset frequency range, the balancing control unit 21 can output a digital signal of corresponding numerical value as a discharge control signal, so that the discharge drive unit 22 balances the battery cell 1 to the specified battery capacity according to the discharge control signal.

[0086] It is understandable that the above embodiment is only an exemplary embodiment for calculating the balanced discharge capacity of each battery unit 1, and those skilled in the art can make adjustments according to actual needs (such as battery type, battery voltage, battery temperature, ambient temperature, etc.).

[0087] In some embodiments of the present application, the discharge drive unit 22 may include a digital-to-analog converter and a MOS transistor drive circuit, etc. The digital-to-analog converter converts the digital signal output by the balancing control unit 21 into an analog voltage in a timing sequence and controls the MOS transistor drive circuit, so that the MOS transistor drive circuit can control the excitation balancing switch M0 in the battery cell 1 to perform discharge balancing.

[0088] It is worth noting that the above content regarding the battery management circuit 100 is intended to clearly illustrate the implementation and verification process of the present application. Those skilled in the art may make equivalent design modifications under the guidance of the present application. For example, the present application may also additionally provide a balancing switch to control battery discharge. The battery balancing module 20 controls the balancing switch to achieve power balancing of multiple battery cells 1.

[0089] Furthermore, in order to further implement the battery management circuit 100 in the embodiment of the present application, based on the battery management circuit 100, the present application also provides a battery management method, which is used to manage multiple battery cells 1, see Figure 11 , Figure 11 A schematic flow chart of a battery management method in an embodiment of the present application is shown, wherein the battery management method includes:

[0090] Step S1101, measuring the electrochemical impedance of multiple battery cells 1 within a preset frequency range;

[0091] Step S1102 : performing balanced discharge on the multiple battery cells 1 according to the electrochemical impedance of the multiple battery cells 1 within a preset frequency range.

[0092] In the embodiment of the present application, the electrochemical impedance of the battery cell 1 within the preset frequency range reflects the characteristics of the battery cell 1. Therefore, the electrochemical impedance of multiple battery cells 1 within the preset frequency range can indicate whether the multiple battery cells 1 are consistent. Then, the battery balancing module 20 balances the battery cells 1 according to the electrochemical impedance of the multiple battery cells 1 within the preset frequency range, thereby effectively controlling the attenuation of the battery according to different aging conditions and ensuring the health of the battery.

[0093] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively correlated with the average electrochemical impedance of the battery cell 1 within a preset frequency range. For example, after obtaining the electrochemical impedance of each battery cell 1 within the preset frequency range, the average electrochemical impedance of each battery cell 1 within the preset frequency range can be calculated, and then the balanced discharge capacity of the battery cell 1 can be determined based on the average electrochemical impedance.

[0094] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively correlated with the peak-to-peak value of the electrochemical impedance of the battery cell 1 within a preset frequency range. For example, after obtaining the electrochemical impedance of each battery cell 1 within the preset frequency range, the peak-to-peak value of the electrochemical impedance of each battery cell 1 within the preset frequency range (i.e., the difference between the maximum electrochemical impedance and the minimum electrochemical impedance) can be calculated, and then the balanced discharge capacity of the battery cell 1 can be determined based on the peak-to-peak value of the electrochemical impedance.

[0095] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively correlated with the RMS value of the electrochemical impedance of the battery cell 1 within a preset frequency range. For example, after obtaining the electrochemical impedance of each battery cell 1 within the preset frequency range, the RMS value of the electrochemical impedance of each battery cell 1 within the preset frequency range can be calculated, and then the balanced discharge capacity of the battery cell 1 can be determined based on the RMS value of the electrochemical impedance.

[0096] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively or negatively correlated with the average electrochemical impedance of the battery cell 1 within a set frequency range, where the set frequency range is within a preset frequency range. For example, after obtaining the electrochemical impedance of each battery cell 1 within the set frequency range, the average electrochemical impedance of each battery cell 1 within the set frequency range can be calculated, and then the balanced discharge capacity of the battery cell 1 can be determined based on the average electrochemical impedance.

[0097] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively or negatively correlated with the peak-to-peak value of the electrochemical impedance of the battery cell 1 within a set frequency range, where the set frequency range is within a preset frequency range. For example, after obtaining the electrochemical impedance of each battery cell 1 within the set frequency range, the peak-to-peak value of the electrochemical impedance of each battery cell 1 within the set frequency range can be calculated, and then the balanced discharge capacity of the battery cell 1 can be determined based on the peak-to-peak value of the electrochemical impedance.

[0098] In some embodiments of the present application, the balanced discharge capacity of each battery cell 1 is positively or negatively correlated with the RMS value of the electrochemical impedance of the battery cell 1 within a set frequency range, where the set frequency range is within a preset frequency range. For example, after obtaining the electrochemical impedance of each battery cell 1 within the set frequency range, the RMS value of the electrochemical impedance of each battery cell 1 within the set frequency range can be calculated, and then the balanced discharge capacity of the battery cell 1 can be determined based on the RMS value of the electrochemical impedance.

[0099] The present application also provides a battery management system including the aforementioned battery management circuit 100. The battery management system may be, but is not limited to, a backup battery management system, a power lead-acid battery management system, an energy storage lithium battery management system, a 3C lithium battery management system, or an EV lithium battery management system. Because the battery management system of the present application includes the battery management circuit 100 described in the aforementioned embodiment, it possesses all the beneficial effects of the battery management circuit 100 in the aforementioned embodiment and will not be further elaborated here.

[0100] The present application also provides a chip including the aforementioned battery management circuit 100. An integrated circuit (IC) is also referred to as a chip, and the chip may be, but is not limited to, a system-on-chip (SOC) chip or a system-in-package (SIP) chip. Because the chip of the present application includes the battery management circuit 100 described in the aforementioned embodiment, it possesses all the beneficial effects of the battery management circuit 100 described in the aforementioned embodiment and will not be further elaborated here.

[0101] An embodiment of the present application also provides an electronic device, which includes a device body and a chip as described above that is provided in the device body. Among them, the electronic device may include a battery management system (BMS). For example, the electronic device may be, but is not limited to, an electric vehicle, energy storage system, mobile power supply, drone, power tool, robot, smart home device, etc. with a battery management system. Electric vehicles may include, but are not limited to, pure electric vehicles (BEV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), extended-range electric vehicles (REEV), or fuel cell vehicles (FCEV). Smart home devices may include, but are not limited to, smart sweepers, smart floor scrubbers, smart window cleaning robots, etc.

[0102] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present application. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A battery management circuit, characterized in that: The battery management circuit is used to control multiple battery cells, including: An electrochemical impedance measurement module, which is used to measure the electrochemical impedance of multiple battery cells within a preset frequency range; A battery balancing module is used to balance the charge of the multiple battery cells according to the electrochemical impedance of the multiple battery cells within a preset frequency range.

2. The battery management circuit according to claim 1, wherein: Each of the battery cells includes an excitation balancing switch; When the battery management circuit measures the electrochemical impedance of the battery cell within a preset frequency range, the electrochemical impedance measurement module controls the excitation equalization switch; When the battery management circuit controls the battery cells to perform balanced discharge, the battery balancing module controls the excitation balancing switch.

3. The battery management circuit according to claim 2, wherein: The battery management circuit further includes a first switch and a second switch; A first end of the first switch is connected to the electrochemical impedance measurement module, and a second end of the first switch is connected to the control end of the excitation balancing switch; A first end of the second switch is connected to the battery balancing module, and a second end of the second switch is connected to the control end of the excitation balancing switch.

4. The battery management circuit according to claim 2, wherein: The electrochemical impedance measurement module includes a signal amplifier and an analog-to-digital converter, and the battery management circuit also includes a third switch and a fourth switch; A first end of the third switch is connected to the signal amplifier, and a second end of the third switch is connected to the analog-to-digital converter; A first end of the fourth switch is connected to the battery unit, and a second end of the fourth switch is connected to the analog-to-digital converter; The signal amplifier is configured to amplify a response signal output by the battery cell when the electrochemical impedance measurement module measures the electrochemical impedance of the battery cell.

5. The battery management circuit according to claim 1, wherein: The electrochemical impedance measurement module includes an excitation unit and a measurement unit; The excitation unit is used to output an excitation signal, and the excitation signal is used to excite the battery unit to output a response signal; The measuring unit is used to determine the electrochemical impedance of the battery cell according to the response signal.

6. The battery management circuit according to claim 5, wherein: The electrochemical impedance measurement module further includes a plurality of first capacitors and a plurality of second capacitors, wherein the first capacitors correspond to the battery cells one-to-one, and the second capacitors correspond to the battery cells one-to-one; The first end of the first capacitor is coupled to the first end of the corresponding battery cell, and the second end of the first capacitor is connected to the measuring unit; A first end of the second capacitor is coupled to a second end corresponding to the battery cell, and a second end of the second capacitor is connected to the measuring unit; The measuring unit is configured to determine the electrochemical impedance of the battery cell according to a voltage difference between the second end of the first capacitor and the second end of the second capacitor.

7. The battery management circuit according to claim 1, wherein: The battery balancing module includes a balancing control unit and a discharge driving unit; The balancing control unit is used to output a discharge control signal to the discharge driving unit according to the electrochemical impedance and battery capacity of each battery cell within a preset frequency range; The discharge driving unit is configured to output a discharge driving signal according to the discharge control signal, so as to drive the battery cells to perform balanced discharge through the discharge driving signal.

8. The battery management circuit according to claim 1, wherein: The balanced discharge capacity of each battery cell is positively correlated with the average electrochemical impedance of the battery cell within a preset frequency range; or The balanced discharge capacity of each battery cell is positively correlated with the peak-to-peak value of the electrochemical impedance of the battery cell within a preset frequency range; or The balanced discharge capacity of each battery cell is positively correlated with the root mean square value of the electrochemical impedance of the battery cell within a preset frequency range.

9. The battery management circuit according to claim 1, wherein: The balanced discharge capacity of each battery cell is positively correlated or negatively correlated with the average electrochemical impedance of the battery cell within a set frequency range; or The balanced discharge capacity of each battery cell is positively or negatively correlated with the peak-to-peak value of the electrochemical impedance of the battery cell within a set frequency range; or The balanced discharge capacity of each battery cell is positively correlated or negatively correlated with the peak-to-peak value of the electrochemical impedance of the battery cell within a set frequency range; or Wherein, the set frequency range is within the preset frequency range.

10. A battery management method, characterized in that: The battery management method is used to manage multiple battery cells, including: measuring the electrochemical impedance of the plurality of battery cells within a preset frequency range; The multiple battery cells are evenly discharged according to the electrochemical impedances of the multiple battery cells within a preset frequency range.

11. A chip, characterized in that: The battery management circuit comprises the battery management circuit according to any one of claims 1 to 9.

12. A battery management system, characterized in that: The battery management circuit comprises the battery management circuit according to any one of claims 1 to 9.

13. An electronic device, characterized in that: The battery management system comprises the chip according to claim 11 or the battery management system according to claim 12.

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