Impedance measurement method for high-voltage battery, and medium, systems and device

Abstract

An impedance measurement method for a high-voltage battery, and a control system, an electric energy system, a storage medium, a battery management system and an electric energy device. The impedance measurement method for a high-voltage battery comprises: on the basis of target currents in a high-voltage battery and target voltages of a plurality of cells, determining impedance information of the plurality of cells, wherein the target currents and the target voltages are currents and voltages of the plurality of cells under the action of a preset excitation signal, and the preset excitation signal is generated by a DC-DC converter.

Description

Impedance measurement method, medium, system and equipment for high-voltage batteries

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202410392556.3, filed with the Patent Office of China on March 29, 2024, entitled “Impedance Measurement Method, Medium, System and Equipment for High-Voltage Batteries,” the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0003] The present disclosure relates to the field of battery technology, and in particular to an impedance measurement method, a control system, an electric energy system, a storage medium, a battery management system, and electric energy equipment of a high-voltage battery. Background Art

[0004] The cell impedance of a high-voltage battery reflects the internal electrochemical characteristics of the cell and is of great significance in research, analysis, and practical applications. For example, by measuring the cell impedance of a high-voltage battery and constructing an electrochemical impedance spectroscopy (EIS), high-precision high-voltage battery state estimation can be achieved through EIS, which deeply understands the battery mechanism.

[0005] However, high-voltage batteries are passive energy sources. In related technologies, the cell impedance of high-voltage batteries can only be measured in a laboratory environment using an electrochemical workstation to generate an excitation signal source, which makes the measurement difficult.

[0006] Summary of the Invention

[0007] The purpose of the present disclosure is to provide an impedance measurement method, control system, electric energy system, storage medium, battery management system and electric energy equipment for a high-voltage battery. A preset excitation signal is generated by a DC-DC converter, and the impedance calculation of the high-voltage battery can be achieved by the preset excitation signal, the target current in the battery module and the target voltage of each battery cell. By reusing existing electrical components, the impedance measurement of the high-voltage battery can be achieved without an electrochemical workstation.

[0008] To achieve the above objectives, according to a first aspect of the present disclosure, a method for measuring the impedance of a high-voltage battery is provided, which is applied to a control system connected to the high-voltage battery, wherein the high-voltage battery includes multiple cells and is connected to a low-voltage battery via a DC-DC converter. The method comprises:

[0009] The impedance information of the multiple battery cells is determined based on the target current in the high-voltage battery and the target voltage of the multiple battery cells; wherein the target current and the target voltage are the current and voltage of the multiple battery cells under the action of a preset excitation signal, and the preset excitation signal is generated by the DC-DC converter, and the preset excitation signal is used to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter, or to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter.

[0010] Optionally, the impedance information includes electrochemical impedance spectroscopy.

[0011] Optionally, the method further includes:

[0012] Obtaining the remaining chargeable capacity of the low-voltage battery;

[0013] When the remaining rechargeable power does not meet the transfer power, a first control instruction is sent, which is used to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter so that the remaining rechargeable power of the low-voltage battery meets the transfer power. The transfer power is the power transferred from the high-voltage battery to the low-voltage battery within the action time of the preset excitation signal.

[0014] Optionally, the control system includes a battery management controller and a collection module connected to the battery management controller, the collection module includes a current collection unit and a voltage collection unit corresponding to each battery cell, and the method further includes:

[0015] Sending a collection instruction to the collection module through the battery management controller;

[0016] For any acquisition unit in the acquisition module, when the acquisition unit receives the acquisition instruction, determining the acquisition time of the acquisition unit for the acquisition instruction based on the acquisition delay time corresponding to the acquisition unit, and performing the acquisition operation through the acquisition unit when the acquisition time arrives;

[0017] After each acquisition unit performs the acquisition operation respectively, the target current in the high-voltage battery and the target voltage of the multiple battery cells are obtained.

[0018] Optionally, the acquisition delay time corresponding to the acquisition unit is determined according to the time difference between each acquisition unit included in the acquisition module receiving the acquisition instruction sent by the battery management controller.

[0019] Optionally, determining the impedance information of the multiple battery cells according to the target current in the high-voltage battery and the target voltage of the multiple battery cells includes:

[0020] Impedance information of the multiple battery cells is determined according to target currents of the high-voltage battery at multiple acquisition moments and target voltages of the multiple battery cells at the multiple acquisition moments.

[0021] Optionally, the method further includes:

[0022] Determine the frequency point to be measured corresponding to the high-voltage battery;

[0023] For any one or more of the frequency points to be measured, generating a corresponding first request according to the one or more frequency points to be measured, wherein the first request is used for the DC-DC converter to generate the preset excitation signal corresponding to the one or more frequency points to be measured;

[0024] The determining impedance information of the multiple battery cells according to the target current in the high-voltage battery and the target voltage of the multiple battery cells includes:

[0025] The impedance information of the multiple battery cells is determined according to the target current and the target voltage corresponding to all the frequency points to be measured.

[0026] Optionally, the preset excitation signal is a current signal, the current signal includes an alternating current component, and the alternating current component is an alternating current signal with multiple frequency points superimposed.

[0027] Optionally, the control system is connected to the DC-DC converter, and the method further comprises:

[0028] In response to determining that the preset condition is met, a first request is sent to the DC-DC converter, where the first request is used for the DC-DC converter to generate the preset excitation signal.

[0029] According to a second aspect of the present disclosure, a control system is provided, which is used to cooperate with a high-voltage battery, a low-voltage battery and a DC-DC converter. The high-voltage battery includes multiple battery cells, and the high-voltage battery is connected to the low-voltage battery through a DC-DC converter. The control system is used to implement the method described in the first aspect.

[0030] According to a third aspect of the present disclosure, an electric energy system is provided, comprising a high-voltage battery, a low-voltage battery, a DC-DC converter and a control system, wherein the high-voltage battery comprises a plurality of battery cells, and the high-voltage battery is connected to the low-voltage battery via a DC-DC converter, and the control system is the control system described in the second aspect.

[0031] According to a fourth aspect of the present disclosure, a method for measuring the impedance of a high-voltage battery is provided, which is applied to an electric energy device. The electric energy device includes a high-voltage battery, a low-voltage battery, a DC-DC converter, and a control system connected to the high-voltage battery. The high-voltage battery includes multiple cells and is connected to the low-voltage battery via a DC-DC converter. The method includes:

[0032] generating a preset excitation signal through the DC-DC converter, wherein the preset excitation signal is used to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter, or to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter;

[0033] The control system determines the impedance information of the multiple battery cells based on the target current in the high-voltage battery and the target voltage of the multiple battery cells, wherein the target current and the target voltage are the current and voltage of the multiple battery cells under the action of a preset excitation signal.

[0034] According to a fifth aspect of the present disclosure, a non-transitory computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the impedance measurement method of the high-voltage battery described in the first aspect of the present disclosure are implemented.

[0035] According to a sixth aspect of an embodiment of the present disclosure, there is provided a battery management system, including:

[0036] a non-volatile memory for storing computer programs executable by the processor;

[0037] A processor is used to execute a computer program to implement the steps of the impedance measurement method of a high-voltage battery described in the first aspect of the present disclosure.

[0038] According to a seventh aspect of an embodiment of the present disclosure, there is provided an electric energy device, comprising the battery management system described in the sixth aspect of the present disclosure.

[0039] Through the above technical solution, the impedance information of the multiple battery cells can be determined according to the target current in the high-voltage battery and the target voltage of the multiple battery cells. Since the target current and the target voltage are the current and voltage of the multiple battery cells under the action of a preset excitation signal, and the preset excitation signal is generated by the DC-DC converter, the preset excitation signal is used to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter, or to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter. Therefore, the measurement of the impedance of a high-voltage battery that is separated from an electrochemical workstation is realized. Moreover, since the existing electrical components such as low-voltage batteries, DC-DC converters, and high-voltage batteries are reused, the measurement cost of the impedance of the high-voltage battery is reduced.

[0040] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0042] FIG1 is a flow chart showing a method for measuring impedance of a high-voltage battery according to an exemplary embodiment.

[0043] FIG2 is a schematic diagram showing an excitation current signal according to an exemplary embodiment.

[0044] Fig. 3 is a schematic diagram showing a single-chain connection between a collection module and a battery management controller according to an exemplary embodiment.

[0045] FIG4 is a schematic diagram showing a loop connection between a collection module and a battery management controller according to an exemplary embodiment.

[0046] Fig. 5 is a schematic diagram showing a sampling time delay according to an exemplary embodiment.

[0047] FIG6 is a schematic diagram showing sampling time delay compensation according to an exemplary embodiment.

[0048] FIG7 is a flow chart showing a method for measuring impedance of a high-voltage battery according to an exemplary embodiment.

[0049] FIG8 is a flow chart showing a method for measuring impedance of a high-voltage battery according to an exemplary embodiment.

[0050] Fig. 9 is a schematic diagram showing connection relationships of a control system according to an exemplary embodiment.

[0051] Fig. 10 is a block diagram showing an electric energy system according to an exemplary embodiment.

[0052] Fig. 11 is a block diagram showing a battery management system according to an exemplary embodiment.

[0053] Fig. 12 is a block diagram showing an electric energy device according to an exemplary embodiment.

[0054] FIG13 is a block diagram of a vehicle according to an exemplary embodiment. DETAILED DESCRIPTION

[0055] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0056] It should be understood that the various steps described in the method embodiments of the present disclosure may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect.

[0057] As used herein, the term "including" and its variations are open-ended, i.e., "including but not limited to." The term "based on" means "based, at least in part, on." The term "one embodiment" means "at least one embodiment," the term "another embodiment" means "at least one additional embodiment," and the term "some embodiments" means "at least some embodiments." Other terms are defined in the following description.

[0058] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0059] Before describing the embodiments of the present disclosure in detail, the electrical components involved in the embodiments of the present disclosure are first introduced.

[0060] In the embodiments of the present disclosure, the low-voltage battery may also be referred to as a starting battery, a low-voltage starting battery, etc., and may be used as a buffer memory for a vehicle power system (e.g., a 12V or 48V vehicle power system) of a motor vehicle. In some scenarios, the low-voltage battery may be designed with a voltage of 6 to 60V (typical values ​​of 12V or 48V). The low-voltage battery may include one or more battery cells.

[0061] In the embodiments of the present disclosure, the high-voltage battery, which may also be referred to as a power battery, traction battery, or energy storage battery, can be used to drive electric vehicles or hybrid vehicles. In some scenarios, the high-voltage battery can be designed with a voltage of 200 to 1000V (typical values ​​are 400V and 800V). The high-voltage battery may include multiple cells.

[0062] A DC-DC converter, also known as a DC-DC converter, is a circuit or electromechanical device that converts electrical energy into a DC power source (or near-DC) power source of a different voltage.

[0063] A battery management system (BMS), also known as a battery control system, is a system used to monitor and manage batteries. It can be located inside or outside the battery. A BMS can include both a high-voltage battery management system and a low-voltage battery management system.

[0064] It should be noted that the impedance measurement method for a high-voltage battery in the embodiments of the present disclosure can be applied not only to the impedance measurement of high-voltage batteries in vehicles, but also to the impedance measurement of high-voltage batteries in other devices. For example, other devices may include vehicles, ships, aircraft, energy storage cabinets, air conditioners, and other equipment that include low-voltage batteries, DC-DC converters, and high-voltage batteries. Unless otherwise specified, the vehicle is used as an example.

[0065] Among them, both the low-voltage battery and the high-voltage battery can be lithium-ion batteries, sodium-ion batteries or other types of batteries.

[0066] FIG1 is a flow chart of a method for measuring the impedance of a high-voltage battery according to an exemplary embodiment. The method is applied to a control system connected to the high-voltage battery. The high-voltage battery includes multiple cells and is connected to a low-voltage battery via a DC-DC converter. As shown in FIG1 , the method for measuring the impedance of a high-voltage battery includes the following steps:

[0067] In step S101, the impedance information of the multiple battery cells is determined based on the target current in the high-voltage battery and the target voltage of the multiple battery cells; wherein the target current and the target voltage are the current and voltage of the multiple battery cells under the action of a preset excitation signal, and the preset excitation signal is generated by a DC-DC converter, and the preset excitation signal is used to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter, or to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter.

[0068] In the embodiment of the present disclosure, a discharge excitation signal, i.e., a preset excitation signal, can be generated on the high-voltage battery side or the low-voltage battery side through a DC-DC converter. Under the action of the preset discharge excitation signal, the high-voltage battery can convert electrical energy to the low-voltage battery through the DC-DC converter, or the low-voltage battery can convert electrical energy to the high-voltage battery through the DC-DC converter.

[0069] In some embodiments, during the process of converting electrical energy from the high-voltage battery to the low-voltage battery via a DC-DC converter, or during the process of converting electrical energy from the low-voltage battery to the high-voltage battery via a DC-DC converter, that is, during the process of a preset excitation signal, a control system connected to the high-voltage battery can be used to collect the target current in the high-voltage battery. In addition, the control system can also be used to collect the voltage of each battery cell in the high-voltage battery, that is, the target voltage of multiple battery cells. The target current in the high-voltage battery can be the output current of the high-voltage battery or the output current of at least one battery cell in the high-voltage battery.

[0070] In some embodiments, after obtaining the target current in the high-voltage battery and the target voltage of multiple battery cells, the impedance information of each battery cell can be determined based on the target current and the target voltage of the single battery cell.

[0071] In some embodiments, for a single battery cell, the impedance information of the battery cell can be calculated based on the target current and the target voltage of the single battery cell, where the impedance information can include a real part value and an imaginary part value.

[0072] In the embodiment of the present disclosure, the impedance measurement of the high-voltage battery may refer to measuring the impedance information of the multiple battery cells included in the high-voltage battery, or it may refer to further obtaining the impedance information of the entire battery based on the impedance information of the multiple battery cells after measuring the impedance information of the multiple battery cells included in the high-voltage battery.

[0073] In some embodiments, the impedance information comprises electrochemical impedance spectroscopy.

[0074] By adopting the above method, the impedance information of the multiple battery cells can be determined according to the target current in the high-voltage battery and the target voltage of the multiple battery cells. Since the target current and the target voltage are the current and voltage of the multiple battery cells under the action of the preset excitation signal, and the preset excitation signal is generated by the DC-DC converter, the preset excitation signal is used to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter, or to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter. Therefore, the measurement of the impedance of the high-voltage battery is realized without the electrochemical workstation. Moreover, since the existing electrical components such as the low-voltage battery, DC-DC converter, and high-voltage battery are reused, the measurement cost of the impedance of the high-voltage battery is reduced.

[0075] In some embodiments, the control system is connected to a DC-DC converter. In this case, the method of the embodiment of the present disclosure may further include the following steps:

[0076] A first request is sent to the DC-DC converter, where the first request is used for the DC-DC converter to generate a preset excitation signal.

[0077] In an embodiment of the present disclosure, the control system is connected to a DC-DC converter. In this way, when the control system determines that the impedance measurement of the high-voltage battery is required, the control system can send a first request to the DC-DC converter to enable the DC-DC converter to generate a preset excitation signal.

[0078] In some embodiments, the control system may determine that the impedance measurement of the high-voltage battery needs to be performed upon receiving a measurement instruction issued by a user.

[0079] In some implementations, sending the first request to the DC-DC converter may include the following steps:

[0080] In response to determining that the preset condition is satisfied, a first request is sent to the DC-DC converter.

[0081] In an embodiment of the present disclosure, when the control system determines that the impedance measurement of the high-voltage battery is required, it can further determine whether the measurement conditions are met, that is, determine whether the preset conditions are met. When the control system determines that the preset conditions are met, it can send a first request to the DC-DC converter in response to determining that the preset conditions are met.

[0082] In some embodiments, the preset conditions include whether the high-voltage battery load is stable, whether the remaining rechargeable capacity of the low-voltage battery satisfies the transfer capacity, whether the high-voltage battery safety operation limit conditions are met, whether the current at the low-voltage battery end during the impedance measurement of the high-voltage battery is less than the maximum allowable charging current of the low-voltage battery, etc.

[0083] When the high-voltage battery load is stable, for example, when the vehicle is in a parked state or a constant current charging state, it is determined that the preset condition is met.

[0084] When the remaining chargeable capacity of the low-voltage battery meets the transfer capacity, the preset condition is determined to be met. This ensures that the energy charged into the high-voltage battery via the DC-DC converter during the impedance measurement of the high-voltage battery will not cause overcharging of the low-voltage battery. The transfer capacity is the amount of energy transferred from the high-voltage battery to the low-voltage battery during the preset excitation signal application time.

[0085] When, during the impedance measurement of the high-voltage battery, the current at the low-voltage battery end is less than the maximum allowable charging current of the low-voltage battery, it is determined that the preset condition is met.

[0086] In some implementations, the method of the embodiment of the present disclosure may further include the following steps:

[0087] In response to determining that the preset condition is met, a first request is sent to the DC-DC converter, where the first request is used for the DC-DC converter to generate a preset excitation signal.

[0088] In some implementations, the method of the embodiment of the present disclosure may further include the following steps:

[0089] Obtain the remaining chargeable capacity of the low-voltage battery;

[0090] When the remaining rechargeable capacity does not meet the transfer capacity, a first control instruction is sent. The first control instruction is used to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter so that the remaining rechargeable capacity of the low-voltage battery meets the transfer capacity. The transfer capacity is the capacity transferred from the high-voltage battery to the low-voltage battery within the preset excitation signal action time.

[0091] Among them, the remaining rechargeable power not meeting the transfer power can be understood as the remaining rechargeable power being less than the transfer power, and the remaining rechargeable power meeting the transfer power can be understood as the remaining rechargeable power being greater than or equal to the transfer power.

[0092] In an embodiment of the present disclosure, when the remaining rechargeable electricity does not meet the transfer electricity, the control system can send a first control instruction, and control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter through the first control instruction, so that the remaining rechargeable electricity of the low-voltage battery meets the transfer electricity, thereby ensuring that the impedance measurement method of the high-voltage battery can be executed normally.

[0093] In some embodiments, the control system of the low-voltage battery connection can calculate the remaining chargeable capacity of the low-voltage battery and send it to the control system of the high-voltage battery connection, so that the control system of the high-voltage battery connection can obtain the remaining chargeable capacity of the low-voltage battery.

[0094] It should be noted that, in the embodiments of the present disclosure, unless otherwise specified, the control system refers to the control system connected to the high-voltage battery.

[0095] In some implementations, in order to obtain more comprehensive impedance information, the method of the embodiment of the present disclosure may further include the following steps:

[0096] Determine the frequency point to be measured corresponding to the high-voltage battery; for any one or more frequency points to be measured, generate a corresponding first request based on the one or more frequency points to be measured, and the first request is used for the DC-DC converter to generate a preset excitation signal corresponding to the one or more frequency points to be measured.

[0097] In this case, determining the impedance information of the multiple cells according to the target current in the high-voltage battery and the target voltage of the multiple cells may include the following steps:

[0098] The impedance information of multiple battery cells is determined based on the target current and target voltage corresponding to all the frequency points to be measured.

[0099] In the disclosed embodiment, the control system can determine the required frequency range for measurement based on the characteristics of the cells in the high-voltage battery and set specific frequency points within the frequency range according to the requirements of a preset algorithm, i.e., the corresponding test frequency points of the high-voltage battery. After determining the test frequency points, a corresponding first request can be generated based on any one or more of the test frequency points, so that the DC-DC converter generates a preset excitation signal corresponding to the one or more test frequency points based on the first request.

[0100] After each target current and target voltage corresponding to a preset excitation signal are collected, a new first request may be generated based on one or more of the remaining frequency points to be measured, and the preset excitation signal generation and the collection of the target current and target voltage may be repeated.

[0101] Subsequently, after generating the first request corresponding to all frequency points, the control system can collect the target current corresponding to all the frequency points to be measured and the target voltage of multiple battery cells. Thus, the control system can further determine the impedance information of each battery cell based on the target current corresponding to all the frequency points to be measured and the target voltage of multiple battery cells.

[0102] Among them, when a corresponding first request is generated according to multiple frequency points to be measured, the subsequent DC-DC converter can generate an excitation signal with multiple frequency points superimposed according to the first request, so that impedance information corresponding to multiple different frequency points can be obtained during one measurement process, thereby improving the measurement speed.

[0103] In some embodiments, the preset excitation signal is a current signal, the current signal includes an alternating current component, and the alternating current component is an alternating current signal with multiple frequencies superimposed.

[0104] In the embodiment of the present disclosure, by superimposing multiple frequency points in the AC current signal, impedance information corresponding to multiple different frequency points can be obtained during one measurement process, thereby improving the measurement speed.

[0105] In some implementations, in order to avoid signal measurement errors and improve signal measurement accuracy, the AC current signal may be superimposed with 1 to 5 frequency points.

[0106] In some embodiments, the excitation current signal may include two parts: an excitation DC current component Idc and an excitation AC current component Iac. The excitation AC current component Iac may be a sinusoidal current signal superimposed with N frequency points. The excitation AC current component Iac may be specifically expressed as follows:

[0107] Iac=Iamp*[sin(ω1*t)+sin(ω2*t)+…+sin(ω_N*t)]

[0108] Wherein, ω_N represents the Nth frequency point, N is a positive integer, generally ranging from 1 to 5, and Iamp represents the amplitude of the excitation current.

[0109] As shown in FIG2 , a schematic diagram of an excitation current signal when N=1 is shown.

[0110] In some embodiments, the sweep frequency range of the excitation current may include 0.01 Hz to 1000 Hz; the amplitude Iamp of the excitation current may be any value between 0.1 A and 5 A; and the DC bias Idc of the excitation current is ≥ the peak value of Iac to ensure that the DC-DC converter is in a unidirectional operating mode.

[0111] In some embodiments, to obtain more comprehensive impedance information, in the embodiment of the present disclosure, determining the impedance information of multiple battery cells based on the target current in the high-voltage battery and the target voltage of the multiple battery cells may include the following steps:

[0112] Impedance information of the multiple battery cells is determined according to target currents in the high-voltage battery at multiple acquisition moments and target voltages of the multiple battery cells at multiple acquisition moments.

[0113] In the embodiment of the present disclosure, corresponding to a preset excitation signal, the control system can respectively collect the target current in the high-voltage battery and the target voltage of multiple battery cells at multiple different collection moments under the action of the preset excitation signal, thereby obtaining the target current in the high-voltage battery at the multiple collection moments and the target voltage of the multiple battery cells at the multiple collection moments. Then, the control system can determine the impedance information of each battery cell based on the target current in the high-voltage battery at the multiple collection moments and the target voltage of the multiple battery cells at the multiple collection moments.

[0114] For example, for the excitation signal Curr(i), at different acquisition times, the control system can acquire (n+1) sets of synchronous sampling data under the excitation of Curr(i), which are respectively expressed as:

[0115] {V1[t0],V1[t1],...,V1[tx]};

[0116] {V2[t0],V2[t1],...,V2[tx]};

[0117] …;

[0118] {Vn[t0],Vn[t1],...,Vn[t]};

[0119] {I[t0],I[t1],...,I[tx]};

[0120] Where Vn[tx] is the target voltage value of the nth cell sampled at time tx, and I[tx] is the current value synchronously sampled at time tx.

[0121] In some embodiments, in order to achieve the acquisition of target current and target voltage, the control system includes a battery management controller and an acquisition module connected to the battery management controller, and the acquisition module includes a current acquisition unit and a voltage acquisition unit corresponding to each battery cell.

[0122] In the embodiment of the present disclosure, a battery management controller (BMC) is used to send an acquisition instruction. The current acquisition unit may be a current sensing unit (CSU), and the voltage acquisition unit may be an analog front end (AFE).

[0123] In some embodiments, to save costs, one voltage acquisition unit can acquire the target voltage of one or more battery cells. For example, the target voltages of four battery cells can all be acquired by the same voltage acquisition unit. That is, the voltage acquisition unit corresponding to different battery cells can be the same.

[0124] There are many ways to connect the acquisition module and the battery management controller.

[0125] Optionally, the acquisition module and the battery management controller can be connected in a single chain. Please refer to Figure 3, which shows a schematic diagram of a single chain connection between the acquisition module and the battery management controller. It should be noted that in a single chain connection, the current acquisition unit can be located anywhere after the battery management controller in the single chain link.

[0126] Optionally, the acquisition module and the battery management controller can be connected in a loop. Please refer to Figure 4, which shows a schematic diagram of a loop connection between the acquisition module and the battery management controller. It should be noted that in the loop connection, the current acquisition unit can be located anywhere in the loop link.

[0127] In the embodiment of the present disclosure, after the acquisition instruction is issued, it is issued to each acquisition unit in the link in sequence. Taking into account the transmission time of the acquisition instruction and the time from the acquisition unit itself receiving the signal instruction to starting sampling, taking the single-chain link shown in Figure 3 as an example, referring to the sampling time delay diagram shown in Figure 5, assuming that the acquisition instruction is issued at time t0, the current acquisition unit starts sampling at time t=t0+Δβ0. Similarly, the first voltage acquisition unit starts sampling at time t=t0+Δβ0+Δβ1, and the Kth voltage acquisition unit starts sampling at time t=t0+Δβ0+Δβ1+…+Δβk.

[0128] It can be seen that there is a sampling time difference between the current and each cell voltage sampling. For example, the data time difference between the current acquisition unit and the Kth voltage acquisition unit is Δt = Δβ1 + ... + Δβk. This leads to data asynchrony and inaccurate phase measurement of impedance information.

[0129] Therefore, when the control system includes a battery management controller and an acquisition module connected to the battery management controller, and the acquisition module includes a current acquisition unit and a voltage acquisition unit corresponding to each battery cell, in order to improve the accuracy of impedance information measurement, in some embodiments, the method of the embodiment of the present disclosure may further include the following steps:

[0130] Sending acquisition instructions to the acquisition module through the battery management controller;

[0131] For any acquisition unit in the acquisition module, when the acquisition unit receives an acquisition instruction, the acquisition time of the acquisition unit for the acquisition instruction is determined based on the acquisition delay time corresponding to the acquisition unit, and when the acquisition time arrives, the acquisition operation is performed by the acquisition unit;

[0132] After each acquisition unit performs an acquisition operation, a target current in the high-voltage battery and a target voltage of multiple battery cells are obtained.

[0133] In the embodiment of the present disclosure, a collection delay time can be set for the collection unit. In this way, after receiving the collection instruction, the collection unit may not perform the collection operation immediately, but can postpone the collection delay time accordingly to obtain the actual collection time for data collection, and then perform the collection operation when the actual collection time arrives.

[0134] By adopting this method, by performing delay compensation after receiving the acquisition instruction, the sampling time difference of each acquisition unit can be reduced to improve data acquisition synchronization, thereby improving the accuracy of the phase measurement of the impedance information.

[0135] In some embodiments, the acquisition delay time corresponding to the acquisition unit is determined according to the time difference between each acquisition unit included in the acquisition module receiving the acquisition instruction sent by the battery management controller.

[0136] Continuing with the above example, please refer to the sampling time delay compensation diagram shown in Figure 6. The K-th voltage acquisition unit is located at the module at the end of the communication and does not require delay, that is, the sampling delay time of the K-th voltage acquisition unit is 0; ...; the sampling delay time of the first voltage acquisition unit is Δβ2+…+Δβk; the sampling delay time of the current acquisition unit is Δβ1+Δβ2+…+Δβk.

[0137] In some embodiments, considering the large number of cells in the high-voltage battery, in order to improve sampling accuracy, the control system may use multiple voltage sampling chips to sample the target voltages of the cells in the high-voltage battery.

[0138] Optionally, each battery cell can be assigned a voltage sampling chip, or a preset number of battery cells can be assigned to the same voltage sampling chip, thereby improving sampling accuracy while saving sampling costs. For example, one voltage sampling chip can be assigned to every four battery cells.

[0139] FIG7 is a flow chart of a method for measuring the impedance of a high-voltage battery according to an exemplary embodiment. The method is applied to an electric energy device, wherein the electric energy device may be, for example, a vehicle, a ship, an aircraft, an energy storage cabinet, an air conditioner, etc. The electric energy device includes a high-voltage battery, a low-voltage battery, a DC-DC converter, and a control system connected to the high-voltage battery. The high-voltage battery includes multiple cells, and the high-voltage battery is connected to the low-voltage battery via the DC-DC converter. As shown in FIG7 , the method for measuring the impedance of a high-voltage battery includes the following steps:

[0140] In step S701, a preset excitation signal is generated by a DC-DC converter, and the preset excitation signal is used to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter, or to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter.

[0141] In step S702, the control system determines the impedance information of the multiple battery cells based on the target current in the high-voltage battery and the target voltage of the multiple battery cells, wherein the target current and target voltage are the current and voltage of the multiple battery cells under the action of a preset excitation signal.

[0142] The detailed description of steps S701-S702 can be referred to the aforementioned embodiment and will not be repeated here.

[0143] By adopting the above method, a preset excitation signal is generated by a DC-DC converter. The preset excitation signal is used to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter, or to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter. The control system can determine the impedance information of multiple battery cells according to the target current in the high-voltage battery and the target voltage of the multiple battery cells, thereby realizing the impedance measurement of the high-voltage battery separated from the electrochemical workstation. Moreover, since the existing low-voltage battery, DC-DC converter, high-voltage battery and other electrical components are reused, the measurement cost of the high-voltage battery impedance is reduced.

[0144] The impedance measurement method of a high-voltage battery disclosed herein is described below with reference to a complete embodiment in conjunction with FIG8 . As shown in FIG8 , the impedance measurement method of a high-voltage battery includes:

[0145] S801, the control system determines whether a preset condition is met, and if so, executes step S802.

[0146] S802, determine whether the remaining chargeable power of the low-voltage battery meets the transfer power. If not, execute step S803; if yes, execute step S804.

[0147] S803: The control system sends a first control instruction.

[0148] The first control instruction is used to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter so that the remaining chargeable power of the low-voltage battery meets the transfer power.

[0149] S804: For any one or more frequency points to be measured, the control system generates a corresponding first request according to the one or more frequency points to be measured.

[0150] S805: The control system sends a first request to the DC-DC converter.

[0151] S806: The DC-DC converter generates a preset excitation signal according to the first request.

[0152] The preset excitation signal is used to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter, or to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter.

[0153] S807 , the control system collects target currents corresponding to multiple collection moments in the high-voltage battery and target voltages corresponding to multiple battery cells at multiple collection moments.

[0154] The target current and target voltage are the current and voltage under the action of the preset excitation signal.

[0155] S808, the control system determines whether the target currents at all the frequencies to be measured and the target voltages of the multiple battery cells are completed. If so, step S809 is executed; if not, the control system returns to step S804.

[0156] S809, the control system determines impedance information of the multiple battery cells based on the target currents corresponding to the high-voltage battery at multiple acquisition times at all the frequencies to be measured and the target voltages corresponding to the multiple battery cells at multiple acquisition times.

[0157] The detailed description of steps S801-S809 can be referred to the aforementioned embodiment and will not be repeated here.

[0158] In another exemplary embodiment, as shown in Figure 9, a control system 910 is also provided. The control system 910 is used to cooperate with a high-voltage battery 920, a low-voltage battery 930 and a DC-DC converter 940. The high-voltage battery 920 includes multiple battery cells, and the high-voltage battery 920 is connected to the low-voltage battery 930 through a DC-DC converter 940. The control system 910 is used to implement the steps of the above-mentioned impedance measurement method of the high-voltage voltage 920.

[0159] In some embodiments, the control system 910 may be one or more chips, controllers, integrated circuits, or computer terminals.

[0160] In another exemplary embodiment, as shown in Figure 10, an electric energy system 1000 is also provided, including a high-voltage battery 920, a low-voltage battery 930, a DC-DC converter 940 and a control system 910. The high-voltage battery 920 includes multiple battery cells, and the high-voltage battery 920 is connected to the low-voltage battery 930 through the DC-DC converter 940.

[0161] In another exemplary embodiment, a non-transitory computer-readable storage medium including a computer program is further provided. When the computer program is executed by a processor, the steps of the above-mentioned method for measuring the impedance of a high-voltage battery are implemented.

[0162] In another exemplary embodiment, as shown in FIG11 , a battery management system 1100 is provided, including:

[0163] a non-volatile memory 1110 for storing computer programs executable by the processor;

[0164] The processor 1120 is configured to execute a computer program to implement the steps of the above-mentioned method for measuring the impedance of a high-voltage battery.

[0165] In another exemplary embodiment, as shown in FIG12 , an electric energy device 1200 is further provided, including the above-mentioned battery management system 1100 .

[0166] 13 is a block diagram of a vehicle 1300 according to an exemplary embodiment. The vehicle 1300 may be an autonomous vehicle, a semi-autonomous vehicle, or a non-autonomous vehicle.

[0167] 13 , vehicle 1300 may include various subsystems, such as an infotainment system 1310, a perception system 1320, a decision-making and control system 1330, a drive system 1340, and an onboard computing platform 1350. Vehicle 1300 may also include more or fewer subsystems, and each subsystem may include multiple components. Furthermore, each subsystem and each component of vehicle 1300 may be interconnected via wired or wireless means.

[0168] In some embodiments, the infotainment system 1310 may include a communication system, an entertainment system, a navigation system, and the like.

[0169] The perception system 1320 may include several sensors for sensing information about the environment surrounding the vehicle 1300. For example, the perception system 1320 may include a global positioning system (which may be a GPS system, a BeiDou system, or another positioning system), an inertial measurement unit (IMU), a laser radar, a millimeter-wave radar, an ultrasonic radar, and a camera.

[0170] The decision control system 1330 may include a computing system, a domain controller, a vehicle controller, an energy dispatcher, a steering system, a high-voltage battery management system, a low-voltage battery management system, a throttle and a braking system, wherein the high-voltage battery management system is used to execute all or part of the steps of the above-mentioned high-voltage battery impedance measurement method.

[0171] Drive system 1340 may include components that provide powered motion for vehicle 1300. In one embodiment, drive system 1340 may include an engine, a power source, a transmission system, and wheels. The engine may be an internal combustion engine, an electric motor, an air compression engine, or a combination thereof. The engine is capable of converting energy provided by the power source into mechanical energy.

[0172] Some or all functions of the vehicle 1300 are controlled by an onboard computing platform 1350. The onboard computing platform 1350 may include at least one processor 1351 and a memory 1352. The processor 1351 may execute instructions 1353 stored in the memory 1352.

[0173] The processor 1351 can be any conventional processor, such as a commercially available CPU. The processor can also include a graphics processor (GPU), a field programmable gate array (FPGA), a system on chip (SOC), an application specific integrated circuit (ASIC), or a combination thereof.

[0174] Memory 1352 can be implemented by any type of volatile or non-volatile memory device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk.

[0175] In addition to instructions 1353 , memory 1352 may also store data, such as road maps, route information, and vehicle location, direction, speed, etc. The data stored in memory 1352 may be used by the onboard computing platform 1350 .

[0176] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0177] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0178] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for measuring the impedance of a high-voltage battery, characterized in that: A control system connected to a high-voltage battery, wherein the high-voltage battery includes multiple cells and is connected to a low-voltage battery via a DC-DC converter, includes: The impedance information of the multiple battery cells is determined based on the target current in the high-voltage battery and the target voltage of the multiple battery cells; wherein the target current and the target voltage are the current and voltage of the multiple battery cells under the action of a preset excitation signal, and the preset excitation signal is generated by the DC-DC converter, and the preset excitation signal is used to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter, or to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter (S101).

2. The method according to claim 1, characterized in that The impedance information includes electrochemical impedance spectroscopy.

3. The method according to claim 1 or 2, characterized in that The method further comprises: Obtaining the remaining chargeable capacity of the low-voltage battery; When the remaining rechargeable power does not meet the transfer power, a first control instruction is sent, which is used to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter so that the remaining rechargeable power of the low-voltage battery meets the transfer power. The transfer power is the power transferred from the high-voltage battery to the low-voltage battery within the action time of the preset excitation signal.

4. The method according to any one of claims 1 to 3, characterized in that The control system includes a battery management controller and a collection module connected to the battery management controller, the collection module includes a current collection unit and a voltage collection unit corresponding to each battery cell, and the method further includes: Sending a collection instruction to the collection module through the battery management controller; For any acquisition unit in the acquisition module, when the acquisition unit receives the acquisition instruction, determining the acquisition time of the acquisition unit for the acquisition instruction based on the acquisition delay time corresponding to the acquisition unit, and performing the acquisition operation through the acquisition unit when the acquisition time arrives; After each acquisition unit performs the acquisition operation respectively, the target current in the high-voltage battery and the target voltage of the multiple battery cells are obtained.

5. The method according to claim 4, characterized in that The acquisition delay time corresponding to the acquisition unit is determined according to the time difference between each acquisition unit included in the acquisition module receiving the acquisition instruction sent by the battery management controller.

6. The method according to any one of claims 1 to 5, characterized in that The determining impedance information of the multiple battery cells according to the target current in the high-voltage battery and the target voltage of the multiple battery cells includes: Impedance information of the multiple battery cells is determined according to target currents of the high-voltage battery at multiple acquisition moments and target voltages of the multiple battery cells at the multiple acquisition moments.

7. The method according to any one of claims 1 to 5, characterized in that The method further comprises: Determine the frequency point to be measured corresponding to the high-voltage battery; For any one or more of the frequency points to be measured, generating a corresponding first request according to the one or more frequency points to be measured, wherein the first request is used for the DC-DC converter to generate the preset excitation signal corresponding to the one or more frequency points to be measured; The determining impedance information of the multiple battery cells according to the target current in the high-voltage battery and the target voltage of the multiple battery cells includes: The impedance information of the multiple battery cells is determined according to the target current and the target voltage corresponding to all the frequency points to be measured.

8. The method according to any one of claims 1 to 7, characterized in that The preset excitation signal is a current signal, the current signal includes an alternating current component, and the alternating current component is an alternating current signal with multiple frequency points superimposed.

9. The method according to any one of claims 1 to 8, characterized in that The control system is connected to the DC-DC converter, and the method further includes: In response to determining that the preset condition is met, a first request is sent to the DC-DC converter, where the first request is used for the DC-DC converter to generate the preset excitation signal.

10. A control system, the control system is used to cooperate with a high-voltage battery, a low-voltage battery and a DC-DC converter, the high-voltage battery includes multiple cells, and the high-voltage battery is connected to the low-voltage battery through a DC-DC converter, characterized in that: The control system is used to implement the steps of the impedance measurement method for a high-voltage battery according to any one of claims 1 to 9.

11. An electric energy system, characterized in that: It includes a high-voltage battery, a low-voltage battery, a DC-DC converter and a control system. The high-voltage battery includes multiple battery cells, and the high-voltage battery is connected to the low-voltage battery through a DC-DC converter. The control system is the control system described in claim 10.

12. A method for measuring the impedance of a high-voltage battery, characterized in that: Applied to electric energy equipment, the electric energy equipment includes a high-voltage battery, a low-voltage battery, a DC-DC converter, and a control system connected to the high-voltage battery, the high-voltage battery includes multiple cells, and the high-voltage battery is connected to the low-voltage battery via the DC-DC converter, the method includes: Generate a preset excitation signal through the DC-DC converter, wherein the preset excitation signal is used to control the high-voltage battery to discharge to the low-voltage battery through the DC-DC converter, or to control the low-voltage battery to discharge to the high-voltage battery through the DC-DC converter (S701); The control system determines the impedance information of the multiple battery cells based on the target current in the high-voltage battery and the target voltage of the multiple battery cells, wherein the target current and the target voltage are the current and voltage of the multiple battery cells under the action of a preset excitation signal (S702).

13. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the impedance measurement method for a high-voltage battery according to any one of claims 1 to 9 are implemented.

14. A battery management system, characterized in that: include: a non-volatile memory for storing computer programs executable by the processor; A processor, configured to execute a computer program to implement the steps of the impedance measurement method for a high-voltage battery according to any one of claims 1 to 9.

15. An electric energy device, characterized in that: Including the battery management system according to claim 14.

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