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

Abstract

An impedance measurement method for a high-voltage battery, and a storage medium, a battery management system, a battery system and an electric energy device. The impedance measurement method for a high-voltage battery comprises: on the basis of a target current in a high-voltage battery and a target voltage of at least one cell, determining impedance information of the at least one cell, wherein the target current and the target voltage are a current and a voltage under the action of a preset excitation signal, and the preset excitation signal is generated by a frequency-adjustable load and used for controlling the high-voltage battery to perform discharge with respect to the frequency-adjustable load.

Description

Impedance measurement method, storage medium, system and electric energy device for high-voltage battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This disclosure claims priority to Chinese patent application number 202410385600.8, filed with the Patent Office of China on March 29, 2024, entitled “Impedance measurement method, storage medium, system and electric energy device 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, storage medium, battery management system, battery system, and electric energy equipment for 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, storage medium, battery management system, battery system and electric energy equipment for a high-voltage battery. A preset excitation signal is generated by a frequency-adjustable load, and the impedance of the high-voltage battery can be calculated based on the preset excitation signal, the target current in the high-voltage battery and the target voltage of at least one 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 high-voltage battery management system. The high-voltage battery includes at least one battery cell, the high-voltage battery management system is connected to the high-voltage battery, and the high-voltage battery is connected to a frequency-adjustable load. The method includes:

[0009] The impedance information of the at least one battery cell is determined based on the target current in the high-voltage battery and the target voltage of the at least one battery cell; wherein the target current and the target voltage are the current and voltage under the action of a preset excitation signal, and the preset excitation signal is generated by the adjustable frequency load, and the preset excitation signal is used to control the high-voltage battery to discharge the adjustable frequency load.

[0010] Optionally, the frequency-adjustable load is a thermal management system, the high-voltage battery management system is connected to the thermal management system, and the thermal management system includes a thermal management device and a frequency adjustment component. The method further includes:

[0011] A first request is sent to the frequency adjustment component, where the first request is used for the frequency adjustment component to generate the preset excitation signal, and the preset excitation signal is used to control the high-voltage battery to discharge the thermal management device.

[0012] Optionally, the thermal management system is determined from a plurality of candidate thermal management systems according to thermal management requirements of the electrical energy equipment.

[0013] Optionally, the thermal management system includes an equipment thermal management system and a battery thermal management system, the equipment thermal management system includes an equipment heating system and an equipment cooling system, the equipment thermal management system is connected to the high-voltage positive and negative ports of the high-voltage battery, and the battery thermal management system is connected to the high-voltage positive and negative bus potentials inside the high-voltage battery.

[0014] Optionally, the impedance information includes electrochemical impedance spectroscopy.

[0015] Optionally, determining the impedance information of the at least one battery cell according to the target current in the high-voltage battery and the target voltage of the at least one battery cell includes:

[0016] The impedance information of the at least one battery cell is determined according to the target current of the high-voltage battery at the multiple acquisition moments and the target voltage of the at least one battery cell at the multiple acquisition moments.

[0017] Optionally, the method further includes:

[0018] Determine the frequency point to be measured corresponding to the high-voltage battery;

[0019] 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 adjustable frequency load to generate the preset excitation signal corresponding to the one or more frequency points to be measured;

[0020] The determining the impedance information of the at least one battery cell according to the target current in the high-voltage battery and the target voltage of the at least one battery cell includes:

[0021] The impedance information of the at least one battery cell is determined according to the target current corresponding to all the frequency points to be measured and the target voltage of the at least one battery cell.

[0022] 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.

[0023] Optionally, the high-voltage battery management 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:

[0024] Sending a collection instruction to the collection module through the battery management controller;

[0025] 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;

[0026] After each acquisition unit performs the acquisition operation respectively, the target current in the high-voltage battery and the target voltage of the at least one battery cell are obtained.

[0027] 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.

[0028] According to a second 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 frequency-adjustable load, and a high-voltage battery management system connected to the high-voltage battery. The high-voltage battery is connected to the frequency-adjustable load, and the high-voltage battery includes at least one battery cell. The method includes:

[0029] generating a preset excitation signal through the frequency-adjustable load, wherein the preset excitation signal is used to control the high-voltage battery to discharge the frequency-adjustable load;

[0030] The high-voltage battery management system determines the impedance information of the at least one battery cell based on the target current in the high-voltage battery and the target voltage of the at least one battery cell, wherein the target current and the target voltage are the current and voltage under the action of a preset excitation signal.

[0031] According to a third 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.

[0032] According to a fourth aspect of an embodiment of the present disclosure, there is provided a battery management system, including:

[0033] a non-volatile memory for storing computer programs executable by the processor;

[0034] 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.

[0035] According to a fifth aspect of an embodiment of the present disclosure, a battery system is provided, comprising: a high-voltage battery, a battery management system and an adjustable frequency load, wherein the battery management system is signal-connected to the high-voltage battery, the adjustable frequency load is electrically connected to the high-voltage battery, the high-voltage battery comprises at least one battery cell, and the battery management system is the battery management system described in the fourth aspect.

[0036] According to a sixth aspect of an embodiment of the present disclosure, there is provided an electric energy device, comprising the battery management system described in the fourth aspect of the present disclosure or the battery system described in the fifth aspect.

[0037] Through the above technical solution, the impedance information of the at least one battery cell can be determined according to the target current in the high-voltage battery and the target voltage of the at least one battery cell. Since the target current and the target voltage are the current and voltage under the action of a preset excitation signal, and the preset excitation signal is generated by the adjustable frequency load, the preset excitation signal is used to control the discharge of the high-voltage battery to the adjustable frequency load. Therefore, the impedance measurement of the high-voltage battery separated from the electrochemical workstation is realized. Moreover, since the existing adjustable frequency load, high-voltage battery and other electrical components are reused, the measurement cost of the impedance of the high-voltage battery is reduced.

[0038] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] 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:

[0040] FIG1 is a flow chart showing a method for measuring impedance of a high-voltage battery according to an exemplary embodiment.

[0041] FIG2 is a diagram showing a connection relationship between a thermal management system and a high-voltage battery according to an exemplary embodiment.

[0042] FIG3 is a diagram showing a connection relationship between a thermal management system and a high-voltage battery according to an exemplary embodiment.

[0043] FIG4 is a diagram showing a connection relationship between a thermal management system and a high-voltage battery according to an exemplary embodiment.

[0044] FIG5 is a schematic diagram showing an excitation current signal according to an exemplary embodiment.

[0045] Fig. 6 is a schematic diagram showing a single-chain connection between a collection module and a battery management controller according to an exemplary embodiment.

[0046] FIG7 is a schematic diagram showing a loop connection between a collection module and a battery management controller according to an exemplary embodiment.

[0047] Fig. 8 is a schematic diagram showing a sampling time delay according to an exemplary embodiment.

[0048] Fig. 9 is a schematic diagram showing sampling time delay compensation according to an exemplary embodiment.

[0049] FIG10 is a flow chart showing a method for measuring impedance of a high-voltage battery according to an exemplary embodiment.

[0050] FIG11 is a flow chart showing a method for measuring impedance of a high-voltage battery according to an exemplary embodiment.

[0051] FIG12 is a structural block diagram showing a battery management system according to an exemplary embodiment.

[0052] FIG13 is a structural block diagram of a battery system according to an exemplary embodiment.

[0053] Fig. 14 is a structural block diagram showing an electric energy device according to an exemplary embodiment.

[0054] FIG15 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 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 at least one battery cell.

[0061] The high-voltage battery management system (BMS) is a system used to monitor and manage high-voltage batteries. It can be installed inside or outside the high-voltage battery.

[0062] 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 high-voltage batteries, adjustable-frequency loads, and high-voltage battery management systems. Unless otherwise specified, the vehicle is used as an example.

[0063] 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 high-voltage battery management system. The high-voltage battery includes at least one battery cell. The high-voltage battery management system is connected to the high-voltage battery, and the high-voltage battery is connected to an adjustable frequency load. As shown in FIG1 , the method for measuring the impedance of a high-voltage battery includes the following steps:

[0064] In step S101, the impedance information of at least one battery cell is determined based on the target current in the high-voltage battery and the target voltage of at least one battery cell; wherein the target current and the target voltage are the current and the voltage under the action of a preset excitation signal, and the preset excitation signal is generated by an adjustable frequency load, and the preset excitation signal is used to control the high-voltage battery to discharge the adjustable frequency load.

[0065] In the embodiment of the present disclosure, a discharge excitation signal, i.e., a preset excitation signal, can be modulated by a frequency-adjustable load. Under the action of the preset discharge excitation signal, the high-voltage battery discharges the frequency-adjustable load, so that the frequency-adjustable load can absorb the preset excitation signal energy released by the high-voltage battery.

[0066] During the high-voltage battery's discharge of the frequency-adjustable load, i.e., during the application of a preset excitation signal, the high-voltage battery management system can collect a target current in the high-voltage battery. Furthermore, the high-voltage battery management system can also collect the voltage of at least one cell in the high-voltage battery, i.e., the target voltage of the at least one cell. The target current in the high-voltage battery can be the output current of the high-voltage battery or the output current of the at least one cell in the high-voltage battery.

[0067] In some embodiments, after obtaining the target current of the high-voltage battery and the target voltage of at least one battery cell, the impedance information of each battery cell can be determined based on the target current and the target voltage of the single battery cell.

[0068] 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.

[0069] 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.

[0070] In some embodiments, the impedance information comprises electrochemical impedance spectroscopy.

[0071] By adopting the above method, the impedance information of at least one battery cell can be determined according to the target current in the high-voltage battery and the target voltage of at least one battery cell. Since the target current and target voltage are the current and voltage under the action of a preset excitation signal, and the preset excitation signal is generated by an adjustable frequency load, the preset excitation signal is used to control the discharge of the high-voltage battery to the adjustable frequency load. Therefore, the impedance measurement of the high-voltage battery separated from the electrochemical workstation is realized. Moreover, since the existing adjustable frequency load, high-voltage battery and other electrical components are reused, the measurement cost of the impedance of the high-voltage battery is reduced.

[0072] In some embodiments, the frequency-adjustable load is a thermal management system, the high-voltage battery management system is connected to the thermal management system, and the thermal management system includes a thermal management device and a frequency adjustment component. In this case, the method of the embodiment of the present disclosure may further include the following steps:

[0073] A first request is sent to the frequency regulation component, where the first request is used for the frequency regulation component to generate a preset excitation signal, where the preset excitation signal is used to control the high-voltage battery to discharge the thermal management device.

[0074] In an embodiment of the present disclosure, the thermal management system can be used as a frequency-adjustable load, wherein the thermal management system may include a frequency adjustment component and a thermal management device, the frequency adjustment component is used to generate a preset excitation signal, and the thermal management device is used to absorb the excitation signal energy released by the high-voltage battery.

[0075] In an embodiment of the present disclosure, when the high-voltage battery management system determines that the impedance measurement of the high-voltage battery is required, the high-voltage battery management system can send a first request, for example, to the frequency adjustment component in the thermal management system, so that the frequency adjustment component generates a preset excitation signal, and then the high-voltage battery can discharge to the thermal management device under the action of the preset excitation signal.

[0076] Optionally, the thermal management system may include an equipment thermal management system and a battery thermal management system. The equipment thermal management system includes an equipment heating system and an equipment cooling system. The equipment thermal management system is connected to the high-voltage positive and negative ports of the high-voltage battery, and the battery thermal management system is connected to the high-voltage positive and negative bus potentials inside the high-voltage battery.

[0077] Optionally, when the electrical energy device is a vehicle, the device heating system can be an onboard PTC (Positive Temperature Coefficient) heating module or heat pump module. The device cooling system can be an onboard air conditioning compressor system. Optionally, the battery thermal management system can be a heating film system inside the high-voltage battery.

[0078] Taking the thermal management system as an on-board PTC heating module as an example, the process of generating a preset excitation signal is described in combination with the connection relationship diagram between a thermal management system and a high-voltage battery shown in Figure 2. As shown in Figure 2, the on-board PTC heating module includes a PTC module and a PTC control switch, and the high-voltage battery includes high-voltage positive and negative ports. The PTC control switch modulates and generates a preset excitation signal based on the first request sent by the high-voltage battery management system. Thus, the high-voltage battery excitation current (discharge direction) flows from DC+ through the PTC module and the PTC control switch to DC-, and the excitation energy is absorbed by the PTC module, and heat is generated. Among them, DC+ / DC- are the high-voltage positive and negative ports of the high-voltage battery.

[0079] Taking the thermal management system as an onboard air conditioning compressor system as an example, the process of generating a preset excitation signal is described in conjunction with the connection diagram between the thermal management system and the high-voltage battery shown in Figure 3. As shown in Figure 3, the onboard air conditioning compressor system includes a switch array and an onboard air conditioning compressor, and the high-voltage battery includes high-voltage positive and negative terminals. The switch array modulates and generates the preset excitation signal based on a first request sent by the high-voltage battery management system. The excitation energy is then absorbed by the onboard air conditioning compressor to generate cooling. DC+ and DC- represent the high-voltage positive and negative terminals of the high-voltage battery.

[0080] Among them, when the thermal management system is an on-board heat pump module, the principle and process of generating a preset excitation signal and absorbing the excitation signal energy released by the high-voltage battery are the same as the principle and process when the thermal management system is an on-board air-conditioning compressor system. You can refer to the above embodiment and will not repeat them here.

[0081] Taking the heating film system in which the thermal management system is a high-voltage battery as an example, the process of generating the preset excitation signal is described in combination with the connection relationship diagram between the thermal management system and the high-voltage battery shown in Figure 4. As shown in Figure 4, the high-voltage battery includes a heating film system and high-voltage positive and negative bus potentials. The heating film system includes a heating film and a heating film control switch. The heating film control switch modulates and generates a preset excitation signal based on the first request sent by the high-voltage battery management system. As a result, the high-voltage battery excitation current (discharge direction) PACK+ passes through the heating film and the heating film control switch and flows into PACK-. The excitation energy is absorbed by the heating film and generates heat in the high-voltage battery. PACK+ / PACK- are the high-voltage positive and negative bus potentials in the high-voltage battery pack, respectively.

[0082] By using the above method, the device thermal management system or battery thermal management system can be used to generate the excitation signal and absorb the excitation energy when measuring the impedance of the high-voltage battery. This can reuse existing thermal management electrical components, reducing measurement costs while ensuring measurement accuracy. The specific analysis process is as follows:

[0083] For example, the internal resistance of a 200Ah high-voltage battery in a new energy vehicle is typically less than 1mΩ. Common battery management systems measure cell voltage with a resolution of approximately 0.1mV. According to Ohm's law, Z(ω) = V(ω) / I(ω), if you want an impedance measurement resolution of 100μΩ, the excitation current signal must be 1A; if you want an impedance measurement resolution of 10μΩ, the excitation current signal must be as high as 10A. High-voltage batteries typically have a voltage range of 300V to 800V. For example, with a 5A current and a 500V battery voltage, the excitation signal power is 2.5kW.

[0084] In the related art, in addition to being able to generate an excitation signal source through an electrochemical workstation to measure the impedance of a high-voltage battery, some manufacturers have integrated the online EIS measurement function of a single battery cell into a chip. In this way, hundreds of battery cells in a high-voltage battery require hundreds of measurement chips. In addition, the excitation current is generated by the EIS measurement chip. In order to reduce power loss, the excitation current is usually small. In this case, in order to improve the accuracy of impedance measurement, it is necessary to improve the voltage sampling resolution of the EIS measurement chip. It is understandable that the greater the voltage sampling resolution, the higher the chip cost. In this application, by using a thermal management system to consume energy and use electricity reasonably, power waste is avoided. Moreover, during the operation of the thermal management system, the current is large, so that the sampling resolution of the voltage sampling unit is large, which reduces the cost of the voltage sampling unit.

[0085] In some embodiments, the thermal management system is determined from a plurality of candidate thermal management systems based on the thermal management requirements of the electrical energy device, such as a vehicle, a ship, an aircraft, an energy storage cabinet, an air conditioner, or the like.

[0086] In the embodiment of the present disclosure, the current thermal management requirements of the electric energy equipment can be obtained, for example, whether the user has a vehicle cooling requirement or a vehicle heating requirement, or whether the user has a battery heating requirement. Thus, the currently used thermal management system can be further determined from multiple candidate thermal management systems based on the thermal management requirements of the electric energy equipment, thereby avoiding power waste.

[0087] In some embodiments, the high-voltage battery management 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.

[0088] In some embodiments, sending the first request to the frequency adjustment component may include the following steps:

[0089] In response to determining that the preset condition is satisfied, a first request is sent to the frequency adjustment component.

[0090] In an embodiment of the present disclosure, when the high-voltage battery management system determines that 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 high-voltage battery management system determines that the preset conditions are met, it can send a first request to the frequency adjustment component in response to determining that the preset conditions are met.

[0091] In some embodiments, the preset condition includes at least one of whether the high-voltage battery load is stable, whether the high-voltage battery safety operation restriction condition is satisfied, and the like.

[0092] 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.

[0093] In some embodiments, the high-voltage battery management system may send a first request to the frequency regulation component if the handshake with the thermal management system is successful.

[0094] 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:

[0095] Determine the frequency point to be tested corresponding to the high-voltage battery; for any one or more frequency points to be tested, generate a corresponding first request based on the one or more frequency points to be tested, and the first request is used for the frequency-adjustable load to generate a preset excitation signal corresponding to the one or more frequency points to be tested.

[0096] In this case, determining the impedance information of at least one battery cell according to the target current in the high-voltage battery and the target voltage of at least one battery cell may include the following steps:

[0097] Impedance information of at least one battery cell is determined according to target currents corresponding to all frequency points to be measured and target voltages of at least one battery cell.

[0098] In the disclosed embodiments, the high-voltage battery management system can determine the required frequency range for measurement based on the characteristics of the cells in the high-voltage battery and set specific frequencies within the frequency range according to preset algorithm requirements, i.e., the corresponding test frequencies for the high-voltage battery. After determining the test frequencies, a corresponding first request can be generated based on any one or more of the test frequencies, so that the frequency-adjustable load generates a preset excitation signal corresponding to the one or more test frequencies based on the first request.

[0099] 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.

[0100] Subsequently, after generating the first request corresponding to all frequency points, the high-voltage battery management system can collect the target current corresponding to all frequency points to be measured and the target voltage of multiple battery cells. Thus, the high-voltage battery management system can further determine the impedance information of each battery cell based on the target current corresponding to all frequency points to be measured and the target voltage of at least one battery cell.

[0101] Among them, when a corresponding first request is generated according to multiple frequency points to be measured, the subsequent adjustable frequency load 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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:

[0106] Iac=Iamp*[sin(ω1*t)+sin(ω2*t)+…+sin(ω_N*t)]

[0107] 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.

[0108] As shown in FIG5 , a schematic diagram of an excitation current signal when N=1 is shown.

[0109] 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 power battery is in a unidirectional working mode.

[0110] In some embodiments, to obtain more comprehensive impedance information, in the embodiment of the present disclosure, determining the impedance information of at least one battery cell according to the target current in the high-voltage battery and the target voltage of at least one battery cell may include the following steps:

[0111] Impedance information of the multiple battery cells is determined according to target currents in the high-voltage battery corresponding to the multiple acquisition moments and target voltages of at least one battery cell corresponding to the multiple acquisition moments.

[0112] In the embodiment of the present disclosure, corresponding to a preset excitation signal, the high-voltage battery management system can collect the target current in the high-voltage battery and the target voltage of at least one battery cell at multiple different collection times under the action of the preset excitation signal, thereby obtaining the target current in the high-voltage battery at the multiple collection times and the target voltage of at least one battery cell at the multiple collection times. Then, the high-voltage battery management system can determine the impedance information of each battery cell based on the target current in the high-voltage battery at the multiple collection times and the target voltage of at least one battery cell at the multiple collection times.

[0113] For example, for the excitation signal Curr(i), at different acquisition times, the high-voltage battery management system can acquire (n+1) sets of synchronous sampling data under the excitation of Curr(i), which are respectively expressed as:

[0114] {V1[t0],V1[t1],...,V1[tx]};

[0115] {V2[t0],V2[t1],...,V2[tx]};

[0116] …;

[0117] {Vn[t0],Vn[t1],...,Vn[t]};

[0118] {I[t0],I[t1],...,I[tx]};

[0119] 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.

[0120] In some embodiments, in order to achieve the acquisition of target current and target voltage, the high-voltage battery management 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.

[0121] 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).

[0122] There are many ways to connect the acquisition module and the battery management controller.

[0123] Optionally, the acquisition module and the battery management controller can be connected in a single chain. Please refer to Figure 6, 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.

[0124] Optionally, the acquisition module and the battery management controller can be connected in a loop. Please refer to Figure 7, 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.

[0125] 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 6 as an example, referring to the sampling time delay diagram shown in Figure 8, 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.

[0126] 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.

[0127] Therefore, when the high-voltage battery management 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:

[0128] Sending acquisition instructions to the acquisition module through the battery management controller;

[0129] 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;

[0130] After each acquisition unit has completed the acquisition operation, a target current in the high-voltage battery and a target voltage of at least one battery cell are obtained.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] Continuing with the above example, please refer to the sampling time delay compensation diagram shown in Figure 9. The K-th voltage acquisition unit is located in 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.

[0135] In some embodiments, considering the large number of battery cells in the high-voltage battery, in order to improve sampling accuracy, when the high-voltage battery includes multiple battery cells, the high-voltage battery management system may use multiple voltage sampling chips to sample the target voltage of the battery cells in the high-voltage battery.

[0136] 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.

[0137] FIG10 is a flow chart of a method for measuring the impedance of a high-voltage battery according to an exemplary embodiment. The method applies an electric energy device, which includes a high-voltage battery, an adjustable-frequency load, and a high-voltage battery management system connected to the high-voltage battery. The high-voltage battery is connected to the adjustable-frequency load, and the high-voltage battery includes at least one battery cell. As shown in FIG10 , the method for measuring the impedance of a high-voltage battery includes the following steps:

[0138] In step S1001 , a preset excitation signal is generated by a frequency-adjustable load, and the preset excitation signal is used to control the high-voltage battery to discharge the frequency-adjustable load.

[0139] In step S1002, the impedance information of at least one battery cell is determined by the high-voltage battery management system based on the target current in the high-voltage battery and the target voltage of at least one battery cell, wherein the target current and target voltage are the current and voltage under the action of a preset excitation signal.

[0140] The detailed description of steps S1001 - S1002 can be referred to the aforementioned embodiment and will not be repeated here.

[0141] By adopting the above method, a preset excitation signal is generated through an adjustable frequency load, and the preset excitation signal is used to control the discharge of the high-voltage battery to the adjustable frequency load. The impedance information of at least one battery cell can be determined by the high-voltage battery management system based on the target current in the high-voltage battery and the target voltage of at least one battery cell, thereby realizing the measurement of the high-voltage battery impedance independent of the electrochemical workstation. Moreover, since the existing adjustable frequency load, high-voltage battery and other electrical components are reused, the measurement cost of the high-voltage battery impedance is reduced.

[0142] The impedance measurement method of a high-voltage battery disclosed herein is described below with reference to a complete embodiment in conjunction with FIG11 . As shown in FIG11 , the impedance measurement method of a high-voltage battery includes:

[0143] S1101, the high-voltage battery management system determines whether a preset condition is met. If so, step S1102 is executed.

[0144] S1102 , the high-voltage battery management system determines a target thermal management system from multiple candidate thermal management systems according to the thermal management requirements of the electric energy device, and establishes a handshake connection with the target thermal management system.

[0145] S1103 : For any one or more frequency points to be measured, the high-voltage battery management system generates a corresponding first request according to the one or more frequency points to be measured.

[0146] S1104 , the high-voltage battery management system sends a first request to the target thermal management system.

[0147] The target thermal management system may include a thermal management device and a frequency adjustment component.

[0148] S1105: The frequency adjustment component generates a preset excitation signal according to the first request.

[0149] Among them, the preset excitation signal is used to control the high-voltage battery to discharge the thermal management device.

[0150] S1106 , the high-voltage battery management system collects target currents corresponding to multiple collection moments in the high-voltage battery, and target voltages corresponding to at least one battery cell at multiple collection moments.

[0151] The target current and target voltage are the current and voltage under the action of the preset excitation signal.

[0152] S1107, the high-voltage battery management system determines whether the target current at all the test frequencies and the target voltage of at least one battery cell are completed. If so, step S1108 is executed; if not, the process returns to step S1103.

[0153] S1108, the high-voltage battery management system determines impedance information of multiple battery cells based on the target currents corresponding to the high-voltage batteries at all the test frequencies at multiple acquisition times and the target voltages corresponding to at least one battery cell at multiple acquisition times.

[0154] The detailed description of steps S1101-S1108 can be referred to the aforementioned embodiment and will not be repeated here.

[0155] 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.

[0156] In another exemplary embodiment, as shown in FIG12 , a battery management system 1200 is further provided, including:

[0157] Non-volatile memory 1210, for storing computer programs executable by the processor;

[0158] The processor 1220 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.

[0159] In another exemplary embodiment, as shown in FIG13 , a battery system 1300 is further provided, including: a high-voltage battery 1310, a battery management system 1320 and an adjustable frequency load 1330, wherein the battery management system 1320 is signal-connected to the high-voltage battery 1310, the adjustable frequency load 1330 is electrically connected to the high-voltage battery 1310, the high-voltage battery 1310 includes at least one battery cell, and the battery management system 1320 is the battery management system 1200 described above.

[0160] In another exemplary embodiment, as shown in FIG. 14 , an electric energy device 1400 is further provided, including the above-mentioned battery management system 1200 or battery system 1300 .

[0161] 15 is a block diagram of a vehicle 1500 according to an exemplary embodiment. The vehicle 1500 may be an autonomous vehicle, a semi-autonomous vehicle, or a non-autonomous vehicle.

[0162] 15 , vehicle 1500 may include various subsystems, such as an infotainment system 1510, a perception system 1520, a decision-making control system 1530, a drive system 1540, and an onboard computing platform 1550. Vehicle 1500 may also include more or fewer subsystems, and each subsystem may include multiple components. Furthermore, each subsystem and each component of vehicle 1500 may be interconnected via wired or wireless means.

[0163] In some embodiments, the infotainment system 1510 may include a communication system, an entertainment system, a navigation system, and the like.

[0164] The perception system 1520 may include a number of sensors for sensing information about the environment surrounding the vehicle 1500. For example, the perception system 1520 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.

[0165] The decision control system 1530 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.

[0166] Drive system 1540 may include components that provide power to vehicle 1500. In one embodiment, drive system 1540 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.

[0167] Some or all functions of the vehicle 1500 are controlled by an onboard computing platform 1550. The onboard computing platform 1550 may include at least one processor 1551 and a memory 1552. The processor 1551 may execute instructions 1553 stored in the memory 1552.

[0168] The processor 1551 can be any conventional processor, such as a commercially available CPU. The processor can also include a graphics processing unit (GPU), a field programmable gate array (FPGA), a system on chip (SOC), an application specific integrated circuit (ASIC), or a combination thereof.

[0169] Memory 1552 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.

[0170] In addition to instructions 1553 , memory 1552 may also store data, such as road maps, route information, and vehicle location, direction, speed, etc. The data stored in memory 1552 may be used by the onboard computing platform 1550 .

[0171] 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.

[0172] 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.

[0173] 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: Applied to a high-voltage battery management system, the high-voltage battery includes at least one battery cell, the high-voltage battery management system is connected to the high-voltage battery, and the high-voltage battery is connected to a frequency-adjustable load, the method comprising: The impedance information of the at least one battery cell is determined based on the target current in the high-voltage battery and the target voltage of the at least one battery cell; wherein the target current and the target voltage are the current and voltage under the action of a preset excitation signal, the preset excitation signal is generated by the adjustable frequency load, and the preset excitation signal is used to control the high-voltage battery to discharge the adjustable frequency load (S101).

2. The method according to claim 1, characterized in that The frequency-adjustable load is a thermal management system, the high-voltage battery management system is connected to the thermal management system, and the thermal management system includes a thermal management device and a frequency adjustment component. The method further includes: A first request is sent to the frequency adjustment component, where the first request is used for the frequency adjustment component to generate the preset excitation signal, and the preset excitation signal is used to control the high-voltage battery to discharge the thermal management device.

3. The method according to claim 2, characterized in that The thermal management system is determined from a plurality of candidate thermal management systems according to thermal management requirements of the electric energy equipment.

4. The method according to claim 2 or 3, characterized in that The thermal management system includes an equipment thermal management system and a battery thermal management system. The equipment thermal management system includes an equipment heating system and an equipment cooling system. The equipment thermal management system is connected to the high-voltage positive and negative ports of the high-voltage battery, and the battery thermal management system is connected to the high-voltage positive and negative bus potentials inside the high-voltage battery.

5. The method according to any one of claims 1 to 4, characterized in that The impedance information includes electrochemical impedance spectroscopy.

6. The method according to any one of claims 1 to 5, characterized in that The determining the impedance information of the at least one battery cell according to the target current in the high-voltage battery and the target voltage of the at least one battery cell includes: The impedance information of the at least one battery cell is determined according to the target current of the high-voltage battery at the multiple acquisition moments and the target voltage of the at least one battery cell 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 adjustable frequency load to generate the preset excitation signal corresponding to the one or more frequency points to be measured; The determining the impedance information of the at least one battery cell according to the target current in the high-voltage battery and the target voltage of the at least one battery cell includes: The impedance information of the at least one battery cell is determined according to the target current corresponding to all the frequency points to be measured and the target voltage of the at least one battery cell.

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 high-voltage battery management 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 at least one battery cell are obtained.

10. The method according to claim 9, 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.

11. 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 frequency-adjustable load, and a high-voltage battery management system connected to the high-voltage battery, the high-voltage battery is connected to the frequency-adjustable load, and the high-voltage battery includes at least one battery cell, the method includes: Generate a preset excitation signal through the frequency-adjustable load, wherein the preset excitation signal is used to control the high-voltage battery to discharge the frequency-adjustable load (S1001); The high-voltage battery management system determines the impedance information of the at least one battery cell based on the target current in the high-voltage battery and the target voltage of the at least one battery cell, wherein the target current and the target voltage are the current and voltage under the action of a preset excitation signal (S1002).

12. 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 10 are implemented.

13. 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 10.

14. A battery system, characterized in that: include: A high-voltage battery, a battery management system and an adjustable frequency load, wherein the battery management system is signal-connected to the high-voltage battery, the adjustable frequency load is electrically connected to the high-voltage battery, the high-voltage battery includes at least one battery cell, and the battery management system is the battery management system according to claim 13.

15. An electric energy device, characterized in that: Including the battery management system according to claim 13 or the battery system according to claim 14.

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