Battery characteristic simulation method and battery characteristic simulation board card

Abstract

The invention provides a battery characteristic simulation method and a battery characteristic simulation board card, and belongs to the technical field of batteries. The battery characteristic simulation method comprises the steps that characteristic parameters of a battery are obtained, the characteristic parameters comprise a time-current value corresponding relation, and a current value represents the amplitude of charging current or discharging current of the battery; based on the characteristic parameters and a battery model, a first battery characteristic simulation signal is output to the battery monitoring unit, the first battery characteristic simulation signal comprises a dynamically changing output voltage value of the battery, and the battery model is pre-constructed based on an equivalent circuit of the battery. The method can accurately simulate the characteristics of a real battery and improve the accuracy of a simulation result.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery characteristic simulation method and a battery characteristic simulation board. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] Battery Management System (BMS) is a crucial component of electric vehicles and other electrical devices. Since batteries can fail due to various reasons such as overcharging / over-discharging, thermal runaway, and aging, an effective BMS is necessary to improve battery safety. Therefore, accurate verification of the BMS software strategy is particularly important. Currently, testing of the software strategy in a BMS often fails to accurately verify the software's functionality and performance. Summary of the Invention

[0004] One objective of this application is to provide a battery characteristic simulation method to alleviate, mitigate, or eliminate the problem in related technologies where the software strategy of the BMS cannot be accurately verified.

[0005] An embodiment of the first aspect of this application provides a battery characteristic simulation method, comprising: acquiring characteristic parameters of the battery, the characteristic parameters including a time-current value correspondence, the current value representing the amplitude of the battery's charging current or discharging current; and outputting a first battery characteristic simulation signal to a battery monitoring unit based on the characteristic parameters and a battery model, the first battery characteristic simulation signal including the dynamically changing output voltage value of the battery, the battery model being pre-constructed based on the battery's equivalent circuit.

[0006] In the technical solution of this application embodiment, a simulation signal is output to the battery monitoring unit based on the battery's characteristic parameters and a pre-built battery model based on the battery's equivalent circuit. This allows for the simulation of relevant characteristics during the battery's charging and discharging process based on key battery parameters, thereby accurately simulating the characteristics of a real battery and improving the accuracy of the simulation results. Furthermore, it enables the monitoring of the simulation results. Using simulation results that can simulate the characteristics of a real battery, accurate verification of the BMS's software strategy can be achieved.

[0007] In some embodiments, outputting a first battery characteristic simulation signal to a battery monitoring unit includes: converting the first battery characteristic simulation signal to a target signal format; and outputting the converted first battery characteristic simulation signal to the battery monitoring unit. Converting the first battery characteristic simulation signal to a target signal format supported by the battery monitoring unit enables the battery monitoring unit to monitor the simulation results.

[0008] In some embodiments, the battery characteristic simulation method further includes: executing a predetermined control strategy on the battery based on a battery model to output a second battery characteristic simulation signal to a battery monitoring unit. The second battery characteristic simulation signal includes the dynamically changing output voltage value of the battery under the predetermined control strategy. By outputting the simulation results of the battery under the predetermined control strategy to the battery monitoring unit based on the battery model, the characteristics of the battery under various states can be simulated according to testing needs, making the simulation results more comprehensive and more consistent with the characteristics of a real battery.

[0009] In some embodiments, the predetermined control strategy includes a balancing control strategy, which is used to balance the individual battery cells in the battery. Simulating the battery under the balancing control strategy can make the battery characteristic simulation results more accurate and can be used to verify the impact of the balancing design on the battery.

[0010] In some embodiments, the battery characteristic simulation method further includes: in response to receiving a shutdown equalization control command, stopping the execution of an equalization control strategy on the battery based on the battery model, wherein the shutdown equalization control command is generated by the battery monitoring unit in response to the output voltage value in the second battery characteristic simulation signal not meeting a threshold condition. Based on the output voltage in the simulation signal, battery equalization can be controlled, thereby enabling more accurate verification of the impact of the equalization design on the battery.

[0011] In some embodiments, the battery characteristic simulation method further includes: outputting a battery state signal to a battery monitoring unit, wherein the battery state signal indicates the state of each individual cell in the battery under the equalization control strategy. The battery state signal identifies the state of each individual cell in the battery under the equalization control strategy and outputs it to the battery monitoring unit, enabling the battery monitoring unit to monitor the battery state under the equalization control strategy in real time and perform corresponding equalization control based on the battery state, thereby improving the comprehensiveness and accuracy of the battery characteristic simulation.

[0012] In some embodiments, the battery model is pre-built according to the following steps: based on the battery's equivalent circuit and a pre-obtained time-open-circuit voltage correspondence, a battery model is established, where the open-circuit voltage indicates the voltage difference between the positive and negative electrodes of the battery in the open-circuit state. By constructing an accurate battery model, the simulation results of battery characteristics can be made closer to those of a real battery, resulting in more realistic simulation results.

[0013] In some embodiments, the characteristic parameters further include the battery's internal resistance, capacitance, and bus impedance. The battery's equivalent circuit includes a first sub-equivalent circuit and a second sub-equivalent circuit connected in series with the first sub-equivalent circuit. The battery's equivalent circuit is determined according to the following steps: determining the first sub-equivalent circuit based on the battery's internal resistance and capacitance; and determining the second sub-equivalent circuit based on the bus impedance. Considering the influence of the battery's internal resistance, capacitance, and bus impedance on the battery model during its construction can improve the accuracy and realism of the battery model.

[0014] In some embodiments, establishing a battery model based on the battery's equivalent circuit and a pre-acquired time-open-circuit voltage correspondence includes: determining the mapping relationship between open-circuit voltage and state of charge (SOC) based on the time-open-circuit voltage correspondence and the pre-acquired time-state of charge (SOC) correspondence, where SOC indicates the battery's remaining charge; and establishing the battery model based on the battery's equivalent circuit and the mapping relationship between open-circuit voltage and SOC. By determining the mapping relationship between open-circuit voltage and SOC, the battery's SOC can be used in battery characteristic simulation, thereby enabling battery characteristic simulation based on the battery's SOC and expanding the application scenarios of battery characteristic simulation methods.

[0015] In some embodiments, determining the mapping relationship between open-circuit voltage and state of charge (SOC) based on the time-open-circuit voltage correspondence and the pre-acquired time-state of charge correspondence includes: dividing the open-circuit voltage into multiple open-circuit voltage groups based on time; dividing the SOC into multiple SOC groups corresponding one-to-one with the multiple open-circuit voltage groups based on time; for each open-circuit voltage group: performing linear fitting on the open-circuit voltage group and the corresponding SOC group to obtain the mapping relationship between the open-circuit voltage group and the corresponding SOC group; and combining the mapping relationships between the multiple open-circuit voltage groups and the multiple SOC groups corresponding one-to-one with the multiple open-circuit voltage groups to obtain the mapping relationship between open-circuit voltage and SOC. Grouping the open-circuit voltage and SOC and then performing linear fitting separately can improve the accuracy of the battery model while reducing the complexity of the calculation process.

[0016] An embodiment of the second aspect of this application provides a battery characteristic simulation board, comprising: a first simulation circuit configured to acquire characteristic parameters of the battery, the characteristic parameters including a time-current value correspondence, the current value representing the amplitude of the battery's charging current or discharging current; and a second simulation circuit configured to output a first battery characteristic simulation signal to a battery monitoring unit based on the characteristic parameters and a battery model, the first battery characteristic simulation signal including the dynamically changing output voltage value of the battery, the battery model being pre-constructed based on the battery's equivalent circuit. Using the battery characteristic simulation board to execute the battery characteristic simulation method in the above embodiment can improve the accuracy of simulation results while reducing the complexity of the simulation equipment and lowering design costs.

[0017] In some embodiments, the second simulation circuit is further configured to perform format conversion on the first battery characteristic simulation signal based on the target signal format; and to output the converted first battery characteristic simulation signal to the battery monitoring unit. Using the second simulation circuit to perform format conversion on the simulation signal and output it to the battery monitoring unit can improve the integration of the battery characteristic simulation board and reduce its footprint.

[0018] In some embodiments, the first simulation circuit stores a battery model. Storing the battery model in the first simulation circuit allows the battery model to be called upon according to simulation requirements, thereby improving simulation efficiency.

[0019] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0020] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0021] Figure 1 This is a flowchart illustrating the battery characteristic simulation method of some embodiments of this application;

[0022] Figure 2 This is a flowchart illustrating the conversion format of the simulation signal for the characteristics of the first battery according to some embodiments of this application;

[0023] Figure 3 This is a schematic flowchart illustrating the process of determining the equivalent circuit of a battery according to some embodiments of this application.

[0024] Figure 4A schematic flowchart illustrating the process of establishing a battery model based on the battery's equivalent circuit and time-open-circuit voltage correspondence for some embodiments of this application;

[0025] Figure 5 This is a flowchart illustrating the process of determining the mapping relationship between open-circuit voltage and state of charge in some embodiments of this application;

[0026] Figure 6 This is a schematic diagram of the equivalent circuit of a battery according to some embodiments of this application;

[0027] Figure 7 This is a schematic diagram of the equivalent circuit of a battery according to some embodiments of this application;

[0028] Figure 8 This is a schematic block diagram illustrating the application scenarios of battery characteristic simulation boards in some embodiments of this application. Detailed Implementation

[0029] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0031] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0032] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0033] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0034] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0035] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0036] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0037] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0038] A Battery Management System (BMS) is a crucial component of electric vehicles and other electrical devices. Since batteries can fail due to various reasons such as overcharging / over-discharging, thermal runaway, and aging, an effective BMS is necessary to improve battery safety. Therefore, accurate validation of the BMS software strategy is of paramount importance.

[0039] Currently, verifying software strategies in a Battery Management System (BMS) often requires simulation equipment such as cell simulators. The cell simulator connects to the BMS and verifies the BMS software by simulating the characteristics of a real battery. However, existing simulation equipment is expensive and only has a single function, unable to comprehensively simulate the various characteristics of a real battery. This makes testing the software strategies in the BMS an inaccurate verification of software functionality and performance.

[0040] To improve the accuracy of BMS software strategy verification, a battery characteristic simulation method was designed. By using a pre-built battery model and based on the received battery characteristic parameters, the battery characteristics can be accurately simulated. This provides simulation results that are more consistent with the actual battery characteristics for BMS software strategy verification, thereby improving the accuracy of the verification.

[0041] The battery characteristic simulation method disclosed in this application can be used, but is not limited to, in the verification process of battery management system software strategies in electrical devices such as vehicles, ships, or aircraft. Using the battery characteristic simulation method disclosed in this application helps improve the accuracy of the simulation results, making them more consistent with the characteristics of real batteries.

[0042] This application provides a battery characteristic simulation method 100. (See reference...) Figure 1 The battery characteristic simulation method 100 includes steps 110 to 120.

[0043] Step 110: Obtain the battery's characteristic parameters. These parameters include the time-current value correspondence. The current value represents the amplitude of the battery's charging or discharging current.

[0044] Step 120: Based on the characteristic parameters and the battery model, output a first battery characteristic simulation signal to the battery monitoring unit. The first battery characteristic simulation signal includes the dynamically changing output voltage value of the battery. The battery model is pre-constructed based on the battery's equivalent circuit.

[0045] In the embodiments of this application, the term "battery" may include a single battery cell or a series, parallel, or hybrid configuration of multiple battery cells (e.g., a battery pack or battery module). The term "Battery Management Unit" (BMU) may refer to a controller used in electric vehicles or other devices to monitor and manage the battery status, or it may refer to a vehicle control unit (VCU), domain control unit (DCU), etc., in a vehicle. These controllers can implement battery management functions within the battery, battery management functions on the vehicle as well as existing vehicle control functions. The embodiments of this application do not limit this.

[0046] In the battery characteristic simulation process, the battery's characteristic parameters are first acquired, for example, by receiving characteristic parameters sent by a host computer. A "host computer" refers to a computing device capable of issuing control commands; for example, an industrial control computer, workstation, or touchscreen can all be used as a host computer. The characteristic parameters include various types of parameters related to battery performance. One or more parameters can be selected and acquired according to the simulation requirements. In step 110, the acquired characteristic parameters may include a time-current value correspondence. This current value indicates the amplitude of the current during battery charging and discharging. In some embodiments, this current value may have different current directions. For example, the charging current and discharging current may have the same amplitude, but due to different current directions, the charging current and discharging current may correspond to different current values.

[0047] The battery model is constructed based on the battery's equivalent circuit, allowing for individual modeling for different battery types. Different battery models can have different structures, corresponding to different battery equivalent circuits. Different battery models can be selected to meet different simulation requirements. In some embodiments, characteristic parameters are input into the selected battery model to generate a first battery characteristic simulation signal. The first battery characteristic simulation signal may include relevant characteristic values ​​of various batteries. In some embodiments, the first battery characteristic simulation signal includes the battery's output voltage value.

[0048] In some embodiments, the first battery characteristic simulation signal also includes the dynamically changing temperature value of the battery, which can simulate the temperature during the battery charging and discharging process, thus expanding the application scenarios of the battery characteristic simulation method.

[0049] After obtaining the first battery characteristic simulation signal, the first battery characteristic simulation signal can be output to the battery monitoring unit, so that the battery monitoring unit can monitor the battery-related characteristic values ​​included in the first battery characteristic simulation signal.

[0050] By outputting simulation signals to the battery monitoring unit based on the battery's characteristic parameters and a pre-built battery model based on the battery's equivalent circuit, the relevant characteristics during the battery's charging and discharging process can be simulated according to the battery's key parameters. This allows for accurate simulation of the characteristics of a real battery, improving the accuracy of the simulation results. Furthermore, the simulation results can be monitored. Using simulation results that accurately simulate the characteristics of a real battery, the software strategy of the BMS can be accurately verified.

[0051] According to some embodiments of this application, reference is made to Figure 2 Step 120 includes steps 210 to 220.

[0052] Step 210: Convert the format of the simulation signal of the first battery characteristics based on the target signal format.

[0053] Step 220: Output the converted first battery characteristic simulation signal to the battery monitoring unit.

[0054] The first battery characteristic simulation signal is converted into a target signal format. The target signal format can be determined based on the communication protocol supported by the battery monitoring unit, thus enabling the battery monitoring unit to receive the output first battery characteristic simulation signal.

[0055] Currently, daisy-chain communication is widely used in battery management systems for electric vehicles. Most chips used in different battery management systems support daisy-chain communication. In some embodiments, the target signal format includes a daisy-chain signal format. In some embodiments, the battery monitoring unit supports wireless communication, and the target signal format can be set according to the communication protocol adopted by the wireless communication module.

[0056] The first battery characteristic simulation signal is converted into a target signal format supported by the battery monitoring unit, enabling the battery monitoring unit to monitor the simulation results.

[0057] According to some embodiments of this application, the battery characteristic simulation method 100 further includes:

[0058] A predetermined control strategy is executed on the battery based on the battery model to output a second battery characteristic simulation signal to the battery monitoring unit. The second battery characteristic simulation signal includes the dynamically changing output voltage value of the battery under the predetermined control strategy.

[0059] For real batteries, different control strategies may be implemented during battery use. Under different control strategies, the battery may be in different states. To make the battery characteristic simulation results more closely resemble the characteristics of a real battery, it is also necessary to simulate the battery under different states during the battery characteristic simulation process. The predetermined control strategy can be the same as the control strategy applicable to a real battery, for example, it may include discharge control commands, protection control commands, equalization control commands, etc. In some embodiments, the predetermined control strategy may be indicated by control commands received from the battery monitoring unit.

[0060] In some embodiments, based on a battery model, a second battery characteristic simulation signal can be generated by executing a corresponding control strategy on the battery according to a predetermined control strategy. The second battery characteristic simulation signal can correspond to the first battery characteristic simulation signal, and both include the same relevant battery characteristic values, such as the battery's output voltage value. However, unlike the first battery characteristic simulation signal, the second battery characteristic simulation signal includes the battery's output voltage value under the predetermined control strategy.

[0061] After obtaining the second battery characteristic simulation signal, it can also be output to the battery monitoring unit, enabling the battery monitoring unit to monitor the battery-related characteristic values ​​included in the second battery characteristic simulation signal. In some embodiments, the second battery characteristic simulation signal can be format-converted, and the converted second battery characteristic simulation signal can be output to the battery monitoring unit.

[0062] Based on the battery model, the simulation results of the battery under a predetermined control strategy are output to the battery monitoring unit. The characteristics of the battery under various states can be simulated according to the test requirements, making the simulation results more comprehensive and more consistent with the characteristics of real batteries.

[0063] According to some embodiments of this application, the predetermined control strategy includes a balancing control strategy. The balancing control strategy is used to perform balancing control on the individual battery cells in the battery.

[0064] Because a battery comprises multiple individual cells, inconsistencies in the states of these cells may arise during use or testing. Battery "balancing control" refers to a series of measures to improve the consistency of the states of all cells, thereby enhancing battery safety and extending its lifespan. Battery balancing control primarily includes passive balancing and active balancing. The principle of passive balancing is as follows: when the states of multiple cells are inconsistent, the higher-energy cells are selectively discharged, consuming the excess energy and reducing the difference between cells, ultimately achieving a balanced state. In passive balancing, the resistance in the battery model can be controlled to dissipate energy and achieve the discharge of higher-energy cells. The principle of active balancing is as follows: when the states of multiple cells are inconsistent, energy is transferred from higher-energy cells to lower-energy cells, reducing the difference between cells and ultimately achieving a balanced state. In active balancing, the current flowing through each cell can be adjusted to achieve energy transfer. Equilibrium control has a significant impact on battery performance. Therefore, in the process of battery characteristic simulation, it is necessary to simulate the battery in an equilibrium state so that the simulation results are closer to the characteristics of the real battery.

[0065] When the predetermined control strategy is the equalization control strategy, the second battery characteristic simulation signal includes the output voltage value of the battery under the equalization control strategy.

[0066] Simulating batteries under equalization control strategies can make the simulation results of battery characteristics more accurate and can be used to verify the impact of equalization design on batteries.

[0067] According to some embodiments of this application, the battery characteristic simulation method further includes:

[0068] Upon receiving a command to disable equalization control, the equalization control strategy based on the battery model is stopped. The command to disable equalization control is generated by the battery monitoring unit in response to the output voltage value in the second battery characteristic simulation signal not meeting a threshold condition.

[0069] After receiving the second battery simulation characteristic signal, if the output voltage value in the second battery simulation characteristic signal does not meet the threshold condition, it indicates that the battery performance in the equalization state may not meet the usage requirements, and it is necessary to stop the equalization control of each battery cell. At this time, the battery monitoring unit will issue a command to turn off equalization control. After receiving the command to turn off equalization control from the battery monitoring unit, the equalization control strategy based on the battery model is stopped. The threshold condition can be designed according to simulation requirements, such as based on the selected battery model or the battery usage scenario, and may include the output voltage value being lower or higher than the threshold voltage, the rate of change of the output voltage value being lower or higher than the threshold rate, etc., which are not limited in this disclosure.

[0070] Based on the output voltage in the simulation signal, the battery balancing can be controlled, thereby enabling a more accurate verification of the impact of the balancing design on the battery.

[0071] According to some embodiments of this application, the battery characteristic simulation method further includes:

[0072] The battery status signal is output to the battery monitoring unit. The battery status signal indicates the status of each individual cell in the battery under the equalization control strategy.

[0073] In some embodiments, upon receiving the equalization control command from the battery monitoring unit, a battery status signal can be generated based on the state of each individual battery cell under the equalization control strategy. This battery status signal is then output to the battery monitoring unit. The battery monitoring unit monitors and controls the battery's state based on the battery status signal.

[0074] The battery status signal identifies the state of each individual cell in the battery under the equalization control strategy and outputs it to the battery monitoring unit. This enables the battery monitoring unit to monitor the battery status under the equalization control strategy in real time and perform corresponding equalization control based on the battery status, thereby improving the comprehensiveness and accuracy of battery characteristic simulation.

[0075] According to some embodiments of this application, the battery model is pre-built according to the following steps:

[0076] A battery model is established based on the battery's equivalent circuit and the pre-obtained time-open-circuit voltage correspondence. The open-circuit voltage indicates the voltage difference between the positive and negative terminals of the battery in the open-circuit state.

[0077] The battery model is constructed based on the battery's equivalent circuit, and the battery's equivalent circuit can be determined first.

[0078] Figure 6 An example of the equivalent circuit of a battery is shown. Figure 6In this circuit, the equivalent circuit of the battery is a second-order RC equivalent circuit. It is determined based on the battery's ohmic internal resistance R0, electrochemical polarization internal resistance R1, electrochemical polarization capacitance C1, concentration polarization internal resistance R2, and concentration polarization capacitance C2.

[0079] Open circuit voltage (OCV) indicates the voltage difference between the positive and negative terminals of a battery when it is in an open-circuit state. Figure 6 In the example shown, the time-open-circuit voltage correspondence can be represented as open-circuit voltage U. oc The correspondence between the value and time.

[0080] exist Figure 6 In the example shown, according to Kirchhoff's voltage theorem, the output voltage U can be calculated using the following formula (1):

[0081] U = U oc +U1+U2 (1)

[0082] Wherein, U1 indicates the voltage difference across R1 and C1, and U2 indicates the voltage difference across R2 and C2, which can be calculated according to the following formulas (2) and (3):

[0083]

[0084]

[0085] Where I indicates the current value flowing through the battery equivalent circuit (i.e., the current value in step 110), t is time, τ1 and τ2 are polarization time constants, and τ1 and τ2 can be calculated according to the following formulas (4) and (5):

[0086] τ1=R1C1 (4)

[0087] τ2=R2C2 (5)

[0088] It should be noted that, Figure 6 The equivalent circuit of the battery shown is merely illustrative. The specific circuit structure of the equivalent circuit, the electrical performance indicators of the battery included, and the process of establishing the battery model can be designed according to simulation requirements, and this disclosure does not limit them.

[0089] By constructing an accurate battery model, the simulation results of battery characteristics can be made closer to those of a real battery, resulting in more realistic simulation results.

[0090] According to some embodiments of this application, the characteristic parameters also include the battery's internal resistance, battery capacitance, and the impedance of the busbars in the battery. The battery's equivalent circuit includes a first sub-equivalent circuit and a second sub-equivalent circuit connected in series with the first sub-equivalent circuit. The battery's equivalent circuit is determined according to process 300. For example... Figure 3 As shown, process 300 includes steps 310 to 320.

[0091] Step 310: Determine the first sub-equivalent circuit based on the battery's internal resistance and capacitance.

[0092] Step 320: Determine the second sub-equivalent circuit based on the impedance value of the busbar in the battery.

[0093] As mentioned above, the equivalent circuit of a battery can include parameters such as the battery's ohmic internal resistance, polarization internal resistance, and polarization capacitance. Figure 6 In the example shown, the internal resistance of the battery may include the ohmic internal resistance R0, the electrochemical polarization internal resistance R1, and the concentration polarization internal resistance R2, and the capacitance of the battery may include the electrochemical polarization capacitance C1 and the concentration polarization capacitance C2.

[0094] Ohmic internal resistance is the internal resistance generated by the resistance of a conductor. It depends on the internal materials and geometry of the battery and is related to the conductivity of the conductor material. Polarization internal resistance is the internal resistance generated by the electrochemical reactions occurring within the battery. When the battery is charged and discharged, an electrochemical reaction occurs between the positive and negative electrodes, leading to polarization. Polarization internal resistance is related to the rate of the chemical reaction and the electron conduction speed within the battery. Polarization internal resistance can further include electrochemical polarization internal resistance and / or concentration polarization internal resistance. Polarization capacitance indicates the battery's ability to accumulate charge between the positive and negative electrodes during charging and discharging. Polarization capacitance can further include electrochemical polarization capacitance and / or concentration polarization capacitance.

[0095] exist Figure 6 In the example shown, the characteristic parameters may include the specific values ​​corresponding to R0, R1, C1, R2, and C2 mentioned above. The specific values ​​corresponding to each indicator can be sent directly to the host computer, or multiple sets of specific values ​​corresponding to each indicator can be integrated into the battery's equivalent circuit, and the host computer can send the selected specific group number, or adaptive identification can be performed based on the simulated battery system to select the corresponding set of specific values.

[0096] Since a battery consists of multiple individual cells connected by a busbar, the impedance of the busbar can affect the accuracy of the battery model. Therefore, the impedance of the busbar needs to be considered when constructing the battery model.

[0097] Figure 7Another example of the equivalent circuit of a battery is shown. Figure 6 On this basis, Figure 7 The impedance value R3 of the busbar is connected in series. Figure 7 In the example shown, it includes according to, for example Figure 6 The first sub-equivalent circuit, as shown, is further defined by the method described, and includes a second sub-equivalent circuit defined by the bus impedance value R3.

[0098] exist Figure 7 In this case, according to Kirchhoff's voltage theorem, the output voltage U can be calculated using the following formula (6):

[0099] U = U oc +U1+U2+IR3 (6)

[0100] Among them, U oc U1 indicates the open-circuit voltage of the battery, U2 indicates the voltage difference between R1 and C1, and I indicates the current flowing through the battery's equivalent circuit.

[0101] It should be noted that, Figure 7 The equivalent circuit of the battery shown is merely illustrative. The specific circuit structures of the first and second sub-equivalent circuits, the electrical performance indicators of the battery and connectors respectively, and the process of establishing the battery model can be designed according to simulation requirements, and this disclosure does not limit them.

[0102] In the process of building a battery model, considering the influence of the battery's internal resistance, capacitance, and bus impedance on the battery model can improve the accuracy and realism of the battery model.

[0103] According to some embodiments of this application, establishing a battery model based on the battery's equivalent circuit and a pre-acquired time-open-circuit voltage correspondence includes process 400. (See reference...) Figure 4 Process 400 includes steps 410 to 420.

[0104] Step 410: Based on the time-open-circuit voltage correspondence and the pre-acquired time-state-of-charge correspondence, determine the mapping relationship between open-circuit voltage and state of charge. State of charge indicates the remaining charge of the battery.

[0105] Step 420: Based on the battery's equivalent circuit and the mapping relationship between open-circuit voltage and state of charge, establish a battery model.

[0106] State of Charge (SoC) indicates the remaining capacity of a battery and can be expressed as the ratio of the remaining capacity to the capacity of a fully charged battery.

[0107] The time-state of charge correspondence can be calculated using the following formula (7):

[0108] SoC = SoC0 + It (7)

[0109] Wherein, SoC0 is the initial state of charge of the battery, I indicates the current flowing through the battery's equivalent circuit, and t is time. In some embodiments, SoC0 may be included in the acquired characteristic parameters.

[0110] The mapping relationship between open-circuit voltage and state of charge is determined by the following formula (8):

[0111] U oc =f(SoC) (8)

[0112] After determining the mapping relationship between open-circuit voltage and state of charge, a battery model can be established based on the battery's equivalent circuit and this mapping relationship.

[0113] exist Figure 7 In the example shown, the output voltage U can be calculated using the following formula (9):

[0114] U = f(SoC) + U1 + U2 + IR3 (9)

[0115] Where f(SoC) indicates the mapping relationship between open circuit voltage and state of charge, U1 indicates the voltage difference across R1 and C1, U2 indicates the voltage difference across R2 and C2, I indicates the current value flowing through the battery equivalent circuit, and R3 indicates the impedance value of the bus.

[0116] By determining the mapping relationship between open-circuit voltage and state of charge, the influence of state of charge is introduced into the battery model, thereby enabling the simulation of battery characteristics based on the battery's state of charge, thus expanding the application scenarios of battery characteristic simulation methods.

[0117] According to some embodiments of this application, reference is made to Figure 5 Step 410 includes steps 510 to 540.

[0118] Step 510: Divide the open-circuit voltage into multiple open-circuit voltage groups based on time.

[0119] Step 520: Based on time, the state of charge is divided into multiple state of charge groups that correspond one-to-one with multiple open-circuit voltage groups.

[0120] Step 530: For each open-circuit voltage group in the multiple open-circuit voltage groups: perform linear fitting on the open-circuit voltage group and the charge state group corresponding to the open-circuit voltage group to obtain the mapping relationship between the open-circuit voltage group and the charge state group corresponding to the open-circuit voltage group.

[0121] Step 540: Combine the mapping relationships between multiple open-circuit voltage groups and multiple charge state groups that correspond one-to-one with the multiple open-circuit voltage groups to obtain the mapping relationship between open-circuit voltage and charge state.

[0122] To reduce computational complexity, open-circuit voltage and state of charge can be divided into multiple corresponding open-circuit voltage groups and multiple state of charge groups, respectively, and the mapping relationship between each open-circuit voltage group and state of charge group can be determined. The multiple open-circuit voltage groups can include all acquired open-circuit voltage values, but none of them overlap. Similarly, the multiple state of charge groups can include all acquired state of charge values, but none of them overlap. The number of open-circuit voltage groups and state of charge groups can be designed according to simulation needs, and this disclosure does not limit this.

[0123] In one embodiment of step 530, the mapping relationship between each open-circuit voltage group and its corresponding state of charge group can be calculated using linear fitting according to the following formula (10):

[0124] U oc =f(SoC) = aSoC + b (10)

[0125] Among them, U oc The open-circuit voltage of the battery is indicated, and the SoC indicates the state of charge corresponding to that open-circuit voltage. The linear coefficients a and b can be obtained using linear fitting.

[0126] After obtaining the mapping relationship between each open-circuit voltage group and its corresponding state of charge group, they can be combined to obtain the mapping relationship between open-circuit voltage and state of charge.

[0127] Grouping open-circuit voltage and state of charge and then performing linear fitting separately can improve the accuracy of the battery model while reducing the complexity of the calculation process.

[0128] Based on the same technical concept, this application provides a battery characteristic simulation board. Embodiments of the battery characteristic simulation board can be referenced from embodiments of the battery characteristic simulation method; repeated details will not be repeated. (See also...) Figure 8 The battery feature simulation board 1100 includes a first simulation circuit 1110 and a second simulation circuit 1120.

[0129] The first simulation circuit 1110 is configured to acquire the characteristic parameters of the battery. These characteristic parameters include the time-current value correspondence. The current value represents the amplitude of the battery's charging or discharging current.

[0130] The second simulation circuit 1120 is configured to output a first battery characteristic simulation signal to the battery monitoring unit 12 based on characteristic parameters and a battery model. The first battery characteristic simulation signal includes the dynamically changing output voltage value of the battery. The battery model is pre-constructed based on the battery's equivalent circuit.

[0131] like Figure 8 As shown, the first simulation circuit 1110 can be used to execute step 110 in the battery characteristic simulation method 100 described in the above embodiments. The second simulation circuit 1120 can be used to execute step 120 in the battery characteristic simulation method 100 described in the above embodiments.

[0132] In some embodiments, the first simulation circuit 1110 and the second simulation circuit 1120 can be separate from each other and communicate with each other via a communication link such as a bus. Figure 8 In the example shown, the communication link C between the first simulation circuit 1110 and the second simulation circuit 1120 can use an Advanced eXtensible Interface (AXI) bus.

[0133] In some embodiments, the first simulation circuit 1110 and the second simulation circuit 1120 may also be integrated into the same simulation circuit.

[0134] In some embodiments, the first simulation circuit 1110 includes a system-on-a-chip (SoC). The second simulation circuit 1120 includes a programmable logic device (PLD). A SoC is an integrated circuit that integrates a computer or other electronic system onto a single chip. SoCs can process digital signals, analog signals, mixed signals, and even higher frequency signals. The logic function of a PLD can be determined by programming the device according to usage requirements, including field-programmable gate arrays (FPGAs). Applying the SoC and the PLD to the first and second simulation circuits respectively can improve the integration of the battery characteristic simulation board and reduce its footprint.

[0135] Using a battery characteristic simulation board to execute the battery characteristic simulation method in the above embodiments can improve the accuracy of simulation results while reducing the complexity of simulation equipment and lowering design costs.

[0136] According to some embodiments of this application, the second simulation circuit 1120 is further configured to perform format conversion on the first battery characteristic simulation signal based on the target signal format; and to output the converted first battery characteristic simulation signal to the battery monitoring unit 12.

[0137] like Figure 8As shown, the battery characteristic simulation signal generated in the first simulation circuit 1110 can be transmitted to the second simulation circuit 1120 via the communication link C, and converted into a target signal format (e.g., daisy-chain signal format) in the second simulation circuit 1120. After the format conversion, the second simulation circuit 1120 outputs the converted battery characteristic simulation signal to the battery monitoring unit 12.

[0138] Using a second simulation circuit to convert the simulation signal format and output it to the battery monitoring unit can improve the integration of the battery characteristic simulation board and reduce its footprint.

[0139] According to some embodiments of this application, a battery model is stored in the first simulation circuit 1110.

[0140] By storing the battery model in the first simulation circuit, the battery model can be called according to simulation requirements, thereby improving simulation efficiency.

[0141] Figure 8 This illustrates one use case for the battery characteristic simulation board 1100. For example... Figure 8 As shown, the host computer 11 and the battery monitoring unit 12 are respectively communicatively connected to the battery characteristic simulation board 1100. In some embodiments, the host computer 11 is communicatively connected to the first simulation circuit 1110, and the battery monitoring unit 12 is communicatively connected to the second simulation circuit 1120. The number of host computers 11 and battery monitoring units 12 included in the battery characteristic simulation system 10 can be designed according to simulation requirements, and this disclosure does not limit this.

[0142] exist Figure 8 In the example shown, the battery characteristic simulation system 10 includes two host computers 11. One host computer 11 is connected to the first simulation circuit 1110 via communication link A. This host computer can be a remote host computer, and communication link A can use Ethernet to achieve remote control of the battery characteristic simulation process. The other host computer 11 is connected to the first simulation circuit 1110 via communication link B. This host computer can be set up at the test site. Communication link B can use Universal Serial Bus (USB), Controller Area Network (CAN) bus, or CAN_FD (CAN with Flexible Data rate) bus, etc. It should be noted that different host computers can use the same hardware and software configuration, but are set up in different test locations.

[0143] In addition, the battery characteristic simulation system 10 also includes two battery monitoring units 12. One battery monitoring unit 12 is connected to the second simulation circuit 1120 via communication link D. This battery monitoring unit can communicate with the second simulation circuit 1120 using daisy-chain signals, and communication link D can use a daisy-chain signal channel. The other battery monitoring unit 12 is connected to the second simulation circuit 1120 via communication link E. This battery monitoring unit and the second simulation circuit 1120 can communicate via serial port. Communication link E can be in the form of a Serial Peripheral Interface (SPI) bus, a Universal Asynchronous Receiver / Transmitter (UART), an Inter-Integrated Circuit (IIC) bus, or an I / O (Input / Output) interface, etc. It should be noted that different battery monitoring units can use the same hardware software configuration, but use different communication protocols to communicate with the second simulation circuit.

[0144] It should be understood that, corresponding to the embodiment of the battery characteristic simulation method 100, the embodiment of the battery characteristic simulation board 1100 may also include more circuits or modules.

[0145] A specific embodiment of this application is described below. It should be understood that this specific embodiment is described for illustrative purposes only and should not be construed as limiting the scope of this application.

[0146] like Figure 8 As shown, the battery characteristic simulation board 1100 includes a first simulation circuit 1110 and a second simulation circuit 1120. The first simulation circuit 1110 uses a system chip, and the second simulation circuit 1120 uses a programmable logic device.

[0147] A pre-built battery model is stored in the system chip of the first simulation circuit 1110. This battery model is based on, for example... Figure 7 The equivalent circuit of the battery shown and the pre-obtained time-open-circuit voltage correspondence are constructed. For example... Figure 7 As shown, the equivalent circuit of the battery includes a first sub-equivalent circuit determined based on the battery's internal resistance and capacitance values, and a second sub-equivalent circuit determined based on the impedance values ​​of the busbars in the battery. The first sub-equivalent circuit is a second-order RC equivalent circuit and is connected in series with the second sub-equivalent circuit. The battery's internal resistance values ​​include: the battery's ohmic internal resistance R0, electrochemical polarization internal resistance R1, and concentration polarization internal resistance R2. The battery's capacitance values ​​include: electrochemical polarization capacitance C1 and concentration polarization capacitance C2. The impedance value of the busbars in the battery is R3.

[0148] After obtaining the time-open-circuit voltage and time-state-of-charge (SOC) correspondences, the open-circuit voltage and SOC are divided into 10 one-to-one correspondence groups based on time. For each open-circuit voltage group, a linear fit is performed with its corresponding SOC group to obtain the mapping relationship between each open-circuit voltage group and its corresponding SOC group. These mappings are then combined to obtain the final mapping relationship between open-circuit voltage and SOC. Based on this mapping relationship and the battery's equivalent circuit, a battery model is established.

[0149] When simulating battery characteristics, the host computer 11 sends the battery's characteristic parameters to the first simulation circuit 1110. These parameters include the time-current value correspondence (I), the battery's initial state of charge (SoC0), and the specific values ​​of R1, C1, R2, and C2. The first simulation circuit 1110 calls the battery model stored in the system chip and inputs these characteristic parameters into the model to generate a corresponding first battery characteristic simulation signal, which includes the battery's output voltage value. This output voltage value changes dynamically over time.

[0150] The first simulation circuit 1110 transmits the first battery characteristic simulation signal to the second simulation circuit 1120 via communication link C (e.g., an AXI bus). In the second simulation circuit 1120, the first battery characteristic simulation signal is converted into a daisy-chain signal format. The second simulation circuit 1120 communicates with the battery monitoring unit 12 via communication link D (e.g., a daisy-chain signal channel). The first signal characteristic simulation signal, converted to a daisy-chain signal format, is transmitted to the battery monitoring unit 12 via communication link D, thereby enabling the monitoring of dynamically changing output voltage values.

[0151] When the battery balancing control strategy needs to be verified, the battery monitoring unit 12 sends a balancing control command, instructing the execution of the balancing control strategy based on the battery model. Upon receiving the balancing control command, the second simulation circuit 1120 transmits it to the first simulation circuit 1110 via a communication link C (e.g., an AXI bus). The first simulation circuit 1110 generates a battery status signal indicating the state of each individual battery cell under the balancing control strategy. The battery status signal is converted into a daisy-chain signal format at the second simulation circuit 1120 and further transmitted to the battery monitoring unit 12.

[0152] The first simulation circuit 1110 also controls the battery model to perform equalization control on the battery according to the equalization control command, generating a second battery characteristic simulation signal, which includes the output voltage value of the battery under the equalization control strategy. Similar to the first battery characteristic simulation signal, the second battery characteristic simulation signal is also converted into a daisy-chain signal format in the second simulation circuit 1120 and further transmitted to the battery monitoring unit 12, thereby realizing the monitoring of the output voltage value under the equalization control strategy.

[0153] When the battery monitoring unit 12 detects that the output voltage value in the second battery characteristic simulation signal does not meet the threshold condition, it sends a command to disable the equalization control. Upon receiving the command, the second simulation circuit 1120 transmits it to the first simulation circuit 1110 via communication link C (e.g., an AXI bus). The first simulation circuit 1110 then stops executing the equalization control strategy based on the battery model according to the command to disable the equalization control.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery characteristic simulation method, characterized in that, include: Obtain the characteristic parameters of the battery, including the time-current value correspondence, wherein the current value represents the amplitude of the charging current or discharging current of the battery; Based on the aforementioned characteristic parameters and battery model, a first battery characteristic simulation signal is output to the battery monitoring unit. The first battery characteristic simulation signal includes the dynamically changing output voltage value of the battery. The battery model is pre-constructed based on the equivalent circuit of the battery.

2. The battery characteristic simulation method according to claim 1, characterized in that, The step of outputting the first battery characteristic simulation signal to the battery monitoring unit includes: The format of the first battery characteristic simulation signal is converted based on the target signal format; and The converted first battery characteristic simulation signal is output to the battery monitoring unit.

3. The battery characteristic simulation method according to claim 1, characterized in that, Also includes: Based on the battery model, a predetermined control strategy is executed on the battery to output a second battery characteristic simulation signal to the battery monitoring unit. The second battery characteristic simulation signal includes the output voltage value of the battery dynamically changing under the predetermined control strategy.

4. The battery characteristic simulation method according to claim 3, characterized in that, The predetermined control strategy includes a balancing control strategy, which is used to perform balancing control on each individual cell in the battery.

5. The battery characteristic simulation method according to claim 4, characterized in that, Also includes: In response to receiving a shutdown equalization control command, the equalization control strategy based on the battery model is stopped. The shutdown equalization control command is generated by the battery monitoring unit in response to the output voltage value in the second battery characteristic simulation signal not meeting the threshold condition.

6. The battery characteristic simulation method according to claim 4, characterized in that, Also includes: The battery status signal is output to the battery monitoring unit, wherein the battery status signal indicates the status of each individual battery cell in the battery under the equalization control strategy.

7. The battery characteristic simulation method according to any one of claims 1-6, characterized in that, The battery model was pre-built according to the following steps: Based on the equivalent circuit of the battery and the pre-obtained time-open-circuit voltage correspondence, the battery model is established, whereby the open-circuit voltage indicates the voltage difference between the positive and negative electrodes of the battery in the open-circuit state.

8. The battery characteristic simulation method according to claim 7, characterized in that, The characteristic parameters also include the internal resistance of the battery, the capacitance of the battery, and the impedance of the busbar in the battery. The equivalent circuit of the battery includes a first sub-equivalent circuit and a second sub-equivalent circuit connected in series with the first sub-equivalent circuit. The equivalent circuit of the battery is determined according to the following steps: Based on the internal resistance and capacitance of the battery, the first sub-equivalent circuit is determined; and The second sub-equivalent circuit is determined based on the impedance value of the busbar in the battery.

9. The battery characteristic simulation method according to claim 7, characterized in that, The process of establishing the battery model based on the battery's equivalent circuit and the pre-acquired time-open-circuit voltage correspondence includes: Based on the time-open-circuit voltage correspondence and the pre-acquired time-state-of-charge correspondence, a mapping relationship between the open-circuit voltage and the state of charge is determined, wherein the state of charge indicates the remaining charge of the battery; and The battery model is established based on the equivalent circuit of the battery and the mapping relationship between the open-circuit voltage and the state of charge.

10. The battery characteristic simulation method according to claim 9, characterized in that, The step of determining the mapping relationship between the open-circuit voltage and the state of charge based on the time-open-circuit voltage correspondence and the pre-acquired time-state of charge correspondence includes: The open-circuit voltage is divided into multiple open-circuit voltage groups based on the time; Based on the time, the state of charge is divided into multiple state of charge groups that correspond one-to-one with the multiple open-circuit voltage groups. For each of the plurality of open-circuit voltage groups: A linear fit is performed on the open-circuit voltage group and the corresponding state-of-charge group to obtain the mapping relationship between the open-circuit voltage group and the corresponding state-of-charge group; and By combining the multiple open-circuit voltage groups and the multiple state-of-charge groups that correspond one-to-one with the multiple open-circuit voltage groups, the mapping relationship between the open-circuit voltage and the state of charge is obtained.

11. A battery characteristic simulation board, characterized in that, include: The first simulation circuit is configured to acquire characteristic parameters of the battery, including a time-current value correspondence, wherein the current value represents the amplitude of the battery's charging current or discharging current. as well as The second simulation circuit is configured to output a first battery characteristic simulation signal to the battery monitoring unit based on the characteristic parameters and the battery model. The first battery characteristic simulation signal includes the dynamically changing output voltage value of the battery. The battery model is pre-constructed based on the equivalent circuit of the battery.

12. The battery characteristic simulation board according to claim 11, characterized in that, The second simulation circuit is also configured to perform format conversion on the first battery characteristic simulation signal based on the target signal format; and to output the converted first battery characteristic simulation signal to the battery monitoring unit.

13. The battery characteristic simulation board according to claim 11, characterized in that, The battery model is stored in the first simulation circuit.

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