Parallel battery pack modeling method and device

Abstract

The present invention provides a parallel battery pack modeling method and device, the parallel battery pack modeling method comprises: generating a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack; solving the state equation to generate a branch current solution of the parallel battery pack; establishing a parallel battery pack model according to the branch current solution, the parallel battery pack model is used to simulate the branch current of the parallel branch. The present invention can write related matrices based on the second-order equivalent model of the battery through the loop current method, and solve the parallel branch current by combining the state equations of the batteries, and then establish a parallel battery module simulation model, thereby realizing the state estimation of the parallel battery module and the analysis of branch unbalanced current.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power testing, and in particular to a parallel battery pack modeling method and device. Background Art

[0002] In recent years, lithium-ion batteries have played an important role in power energy storage with their advantages such as fast response speed and high energy density. Considering safety and cost factors, the single cell capacity of the battery is often limited. The battery energy storage system needs to connect the battery or battery pack in parallel to achieve a higher available capacity. However, the parallel battery has inconsistency under the influence of factors such as internal resistance, capacity, SOC (State of Charge, the available state of the remaining charge in the battery), which restricts the battery charging and discharging current and use conditions to a certain extent, affecting the battery performance. Relevant technical personnel in the industry believe that only series battery packs need to be balanced, because parallel batteries have the same terminal voltage to maintain balance. However, there is no experiment in the prior art to further study this and verify the above conclusion. The change in internal resistance means that the current of the single cell in the parallel battery pack is not the same. At the same time, the current of the single cell is generally not monitored, so the battery management system cannot monitor any changes in branch current. The change in current will change the state of charge, temperature and aging degree of the lithium-ion battery, so the terminal voltage of the parallel single cell is the same but the SOC and aging degree are not necessarily the same. Therefore, modeling and simulating the operating status of large-scale parallel battery groups can provide an important basis for the status analysis of battery energy storage systems.

[0003] In the prior art, there are two main modeling methods for lithium-ion battery modules. One is to estimate the SOC of the parallel module by detecting the branch current and using the ampere-hour integration method according to the model parameters of each single cell and the input voltage and current of the parallel module. An important premise of this method is the real-time detection of the branch current of the parallel module, which is very difficult to achieve in practice and has high cost. The other method is a binary modeling method based on the charge and discharge curve. The voltage curve of the lithium battery will shift up and down at different charge and discharge rates. Based on this, a voltage curve database of lithium batteries at different charge and discharge rates can be established, and then the relationship between the single cell voltage and current at any charge and discharge rate is obtained through interpolation, and the calculation simulation of the branch current of the parallel battery module is realized, thereby realizing the state estimation of the battery module. The defect of this method is that it requires a large number of battery voltage curves at different charge and discharge rates, and is only applicable to the case where two batteries are connected in parallel. When the number of battery modules in parallel is large, they need to be connected in parallel equivalently, and the calculation is complicated.

[0004] Therefore, there is an urgent need for a modeling method that can calculate the branch current of parallel battery packs and is suitable for large-scale parallel battery packs. Summary of the invention

[0005] The parallel battery pack modeling method and device provided by the present invention can write the relevant matrices based on the second-order equivalent model of the battery through the loop current method, and solve the parallel branch current by combining the state equations of the batteries, and then establish a parallel battery module simulation model, thereby realizing the state estimation of the parallel battery module and the analysis of branch unbalanced current.

[0006] In order to achieve the above objectives, in a first aspect, this party provides a parallel battery pack modeling method, comprising:

[0007] Generate a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack;

[0008] Solving the state equation to generate a branch current solution of the parallel battery group;

[0009] A parallel battery pack model is established according to the branch current solution, and the parallel battery pack model is used to simulate the branch current of the parallel branch.

[0010] In one embodiment, generating the state equation of the parallel battery pack according to the second-order equivalent model of the parallel battery pack includes:

[0011] Establishing a second-order RC model and a state response equation of a single battery in the parallel battery pack;

[0012] The state equation of the parallel battery group is generated according to the second-order RC model of the single battery and the state equation.

[0013] In one embodiment, solving the state equation includes:

[0014] Establishing a loop current matrix of the parallel battery pack;

[0015] The state equation is solved based on the loop current matrix.

[0016] In one embodiment, the branch current solution includes: OCV, ohmic internal resistance and polarization parameters of the battery.

[0017] In a second aspect, the present invention provides a parallel battery pack modeling device, the device comprising:

[0018] A state equation generating module, used for generating a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack;

[0019] A state equation solving module, used for solving the state equation to generate a branch current solution of the parallel battery pack;

[0020] The battery pack model building module is used to build a parallel battery pack model according to the branch current solution, and the parallel battery pack model is used to simulate the branch current of the parallel branch.

[0021] In one embodiment, the state equation generation module includes:

[0022] A single cell state equation establishing unit, used to establish a second-order RC model and a state response equation of a single cell in the parallel battery pack;

[0023] A state equation generating unit is used to generate a state equation of the parallel battery group according to the second-order RC model and the state equation of the single battery.

[0024] In one embodiment, the state equation solving module includes:

[0025] A current matrix establishing unit, used for establishing a loop current matrix of the parallel battery pack;

[0026] A state equation solving unit is used to solve the state equation according to the loop current matrix.

[0027] In one embodiment, the branch current solution includes: OCV, ohmic internal resistance and polarization parameters of the battery.

[0028] In a third aspect, the present invention provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a parallel battery pack modeling method when executing the program.

[0029] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a parallel battery pack modeling method.

[0030] From the above description, it can be seen that the parallel battery pack modeling method and device provided in the embodiment of the present invention first generate the state equation of the parallel battery pack based on the second-order equivalent model of the parallel battery pack; then, solve the state equation to generate the branch current solution of the parallel branch of the parallel battery pack; finally, establish the parallel battery pack model based on the branch current solution, and the parallel battery pack model is used to simulate the branch current of the parallel branch. According to the parallel battery pack modeling method provided in the embodiment of the present invention, the obtained parallel battery pack model can simulate the operating state of a large-scale parallel battery pack, and thus can provide an important basis for the state analysis of the battery energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 A schematic diagram of a flow chart of a parallel battery pack modeling method provided in an embodiment of the present invention;

[0033] Figure 2 A schematic flow chart of step 100 of a parallel battery pack modeling method in an embodiment of the present invention;

[0034] Figure 3 Schematic diagram of an equivalent circuit model of a second-order RC model in an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of an equivalent circuit model of a parallel battery pack in an embodiment of the present invention;

[0036] Figure 5 A schematic flow chart of step 200 of a parallel battery pack modeling method in an embodiment of the present invention;

[0037] Figure 6 It is a flow chart of a parallel battery pack modeling method in a specific application example of the present invention;

[0038] Figure 7 It is a schematic diagram of the simulation results of the branch current of the three-parallel battery module in a specific application example of the present invention;

[0039] Figure 8 It is a schematic diagram of the actual value of the branch current of the three-parallel battery module in a specific application example of the present invention;

[0040] Fig. 9 It is a schematic diagram of relative error in a specific application example of the present invention;

[0041] Fig.10 A schematic diagram of the structure of a parallel battery pack modeling device according to an embodiment of the present invention;

[0042] Fig.11 Schematic diagram of the structure of the state equation generating module 10 in an embodiment of the present invention;

[0043] Fig.12 Schematic diagram of the structure of the state equation solving module 20 in an embodiment of the present invention;

[0044] Fig.13 It is a schematic diagram of the structure of an electronic device in an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0047] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0048] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0049] The embodiment of the present invention provides a specific implementation method of a parallel battery pack modeling method, see Figure 1 , the method specifically includes the following contents:

[0050] Step 100: Generate a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack.

[0051] Specifically, the state equation and equivalent model of the single cell in the parallel battery pack are first established, and the equivalent model of the single cell can verify its state equation, and the equivalent model and state equation of the parallel battery pack are established based on the verification.

[0052] Preferably, the battery type in the parallel battery pack is a lithium battery, and the number of the lithium batteries is 2-10, that is, the number of lithium batteries included in the parallel battery pack can be any one of 2 to 10, for example, a parallel battery pack consisting of 2 lithium batteries or 6 lithium batteries. Furthermore, the embodiment of the present invention also provides a specific parallel battery pack embodiment: there are five batteries in parallel in the battery pack, wherein the capacity of a single battery is 70Ah, the capacity after parallel connection is 350Ah, the voltage range is 3.5V-5.65V, the battery pack is placed in a 25°C incubator, and the charging method is 0.7C constant current charging.

[0053] Step 200: Solve the state equation to generate a branch current solution of the parallel battery group.

[0054] Specifically, the relevant matrices are listed through the loop current method, and the state equations of the combined batteries are used to solve the parallel branch currents.

[0055] Step 300: Establish a parallel battery pack model according to the branch current solution, wherein the parallel battery pack model is used to simulate the branch current of the parallel branch.

[0056] Solve the OCV, ohmic internal resistance and polarization parameters of the battery at the current moment, and finally iterate again to obtain a new branch current, and so on, and finally establish a parallel battery pack model. It can be understood that the parallel battery pack model obtained by step 300 can simulate the operating state of a large-scale parallel battery pack, and can be simulated and calculated to achieve state estimation of a large-scale parallel battery pack, which can provide an important basis for the state analysis of the battery energy storage system.

[0057] From the above description, it can be seen that the parallel battery pack modeling method provided by the embodiment of the present invention first generates the state equation of the parallel battery pack according to the equivalent model of the parallel battery pack; then, solves the state equation to generate the branch current solution of the parallel battery pack; finally, establishes the parallel battery pack model according to the branch current solution. The present invention can realize the calculation of the parallel branch current according to the performance parameters and state equation of the battery, and then estimate the state of the parallel battery pack, eliminating the detection link of the parallel branch current and simplifying the process; for large-scale parallel battery packs, the use of computers to solve the equations greatly speeds up the solution speed and accuracy; at the same time, the parallel battery pack established by the present invention can be used for the analysis of unbalanced current in parallel branches, providing a reference basis for the safe operation of the module.

[0058] In one embodiment, see Figure 2 , step 100 comprises:

[0059] Step 101: Establishing a second-order RC model and a state response equation of a single battery in the parallel battery pack;

[0060] At present, there are many equivalent circuit models for batteries. Among them, the first-order RC equivalent circuit model has good accuracy and small calculation amount, and has been widely used. Adding an RC parallel network to the first-order RC model constitutes a second-order RC model (see Figure 3 ), compared with the first-order RC circuit, the second-order RC model adds an RC link, which can further divide the polarization effect in the charging and discharging process of lithium-ion batteries into electrochemical polarization and concentration polarization, and has higher accuracy.

[0061] In the second-order RC model, the state response equation of the single cell is established by Kirchhoff's voltage law as shown in formula (1):

[0062]

[0063] In the above formula, I is the current, t is the time, R Ω is the ohmic internal resistance, e is the natural constant, U O is the terminal voltage of the battery, U ocv is the open circuit voltage of the battery (U OCV1 , U OCV2 , U OCV3 ...represents the open circuit voltage of different batteries, and the meanings of other parameters are similar), U p1 and U p2 is the polarization voltage of the battery, and the polarization parameter R p1 , C p1 , R p2 , C p2 , respectively represent the electrochemical polarization internal resistance, electrochemical polarization capacitance, concentration polarization internal resistance and concentration polarization capacitance of lithium battery. Ohmic internal resistance R Ω It can be obtained by formula (2):

[0064]

[0065] In the above formula, ΔU is the change in voltage, ΔI is the change in current, and the polarization parameter R is p1 , C p1 , R p2 , C p2 , which can be obtained by least squares fitting, and the OCV curve uses the voltage curve when charging and discharging at a low current of 0.05C.

[0066] Step 102: Generate a state equation of the parallel battery group according to the second-order RC model and the state equation of the single battery.

[0067] Based on the state equation and the second-order equivalent circuit model of the monomer (i.e., a single battery) in step 101, the second-order equivalent circuit model of N batteries (N is preferably 2-10) connected in parallel to form a parallel battery pack is as follows: Figure 4As shown, the corresponding state equation is:

[0068] According to Kirchhoff's voltage law, we can get:

[0069] U=U OCV1 +I1R Ω1 +U P11 +U P12

[0070] U=U OCV2 +I2R Ω2 +U P21 +U P22

[0071] U=U OCV3 +I3R Ω3 +U P31 +U P32 …

[0072] U=U OC V n +I n R Ω4 +U Pn1 +U Pn2 (3)

[0073] According to Kirchhoff's current law:

[0074] I=I1+I2+I3+…+I n (4)

[0075] In one embodiment, see Figure 5 , step 200 comprises:

[0076] Step 201: Establishing a loop current matrix of the parallel battery pack;

[0077] The loop current method sets the current of each independent loop as an unknown quantity, lists the voltage equations of the independent loops according to Kirchhoff's voltage law, and then solves them simultaneously. The loop current is a current that flows along the loop based on the principle of current continuity. It satisfies Kirchhoff's current law. In a circuit with b branches and n nodes, the loop currents flowing along the selected (b-n+1) independent loops are independent. Therefore, to calculate the circuit using this method, it is necessary to establish (b-n+1) independent equations with loop currents as unknown quantities. An independent loop means that the KVL equations in the loop are linearly independent. In circuit calculations, the basic loop of the circuit (when the circuit is a planar network, its mesh is often taken) is usually taken as an independent circuit.

[0078] Step 202: Solve the state equation according to the loop current matrix.

[0079] In step 201 and step 202, by associating equation (3) and equation (4), the loop current matrix equation of n parallel battery groups can be listed as:

[0080]

[0081] When solving the above matrix equation, the branch current I of the k parallel branches of n parallel batteries is k is an unknown quantity, polarization voltage U Pk1 and U Pk2 are all unknown quantities, that is, there are 3n unknown quantities in total. At the same time, there are 2n state differential equations for the 2n RC parallel branches. By combining the above 3n equations, the solution of the second-order RC equivalent circuit state equation can be obtained, that is, formula (6) and formula (7).

[0082]

[0083]

[0084] It should be noted that when solving differential equations, all variables except the state variable must be known, that is, the branch current I k There must be an initial value. Since the polarization voltage of each branch is 0 at the initial moment of the simulation, and its corresponding polarization resistance and polarization capacitance are also 0, it can be considered that the branch current is distributed according to the OCV and ohmic internal resistance of the monomer at the initial moment of the simulation, so that the initial value of each branch current can be determined, and then the initial value of the branch current is used as a known quantity of the polarization voltage state differential equation to solve the polarization voltage at the next moment, and then solve the OCV, ohmic internal resistance and polarization parameters of the battery at this moment, and finally iterate again to obtain a new branch current, and so on.

[0085] In one embodiment, the branch current solution includes: OCV, ohmic internal resistance and polarization parameters of the battery, wherein the polarization parameters include: electrochemical polarization internal resistance, electrochemical polarization capacitance, concentration polarization internal resistance and concentration polarization capacitance of the lithium battery.

[0086] From the above description, it can be seen that the parallel battery pack modeling method provided by the embodiment of the present invention first generates the state equation of the parallel battery pack based on the equivalent model of the parallel battery pack; then, solves the state equation to generate the branch current solution of the parallel battery pack; finally, establishes the parallel battery pack model based on the branch current solution. Specifically, the present invention is based on the second-order equivalent model of the battery, establishes the relevant matrix through the loop current method, and realizes the solution of the parallel branch current by the state equation of the battery, and then establishes the parallel battery module simulation model, and finally realizes the state estimation of the parallel battery module and the analysis of the branch unbalanced current.

[0087] To further illustrate the present solution, the present invention takes three lithium iron phosphate batteries connected in parallel as an example to provide a specific application example of the parallel battery pack modeling method, which specifically includes the following contents, see Figure 6 .

[0088] In the specific application example of the present invention, three lithium iron phosphate batteries are connected in parallel as an example. The capacity of each single cell is 60Ah, and the capacity after parallel connection is 180Ah. The voltage range is 2.5V-3.65V. The battery pack is placed in a 25°C incubator and the charging method is 0.5C constant current charging.

[0089] S1: Calculate SOC based on battery capacity and initial SOC.

[0090] It is understandable that SOC (State of charge) is used to reflect the remaining capacity of the battery. Its value is defined as the ratio of the remaining capacity to the battery capacity, and is usually expressed as a percentage. Its value range is 0 to 1. When SOC = 0, it means that the battery is fully discharged, and when SOC = 1, it means that the battery is fully charged. The battery SOC cannot be measured directly, and its size can only be estimated through parameters such as battery terminal voltage, charge and discharge current, and internal resistance. These parameters will also be affected by many uncertain factors such as battery aging, ambient temperature changes, and vehicle driving conditions.

[0091] S2: Determine whether to continue the simulation calculation according to the SOC calculation result.

[0092] S3: When the simulation calculation continues, it is determined whether to query the discharge parameters or the charge parameters according to the current size.

[0093] S4: Solve the branch current by using the simultaneous state equations according to the charging parameter query result or the discharging parameter query result.

[0094] S5: Output battery branch current, polarization voltage and other parameters.

[0095] In step S1 to step S5, the input parameters of the parallel battery pack simulation model include the OCV, R Ω , R p1 , R p2 and C P1 , C p2The table lookup module in related tools (such as Matlab software) can linearly interpolate the parameters in the entire SOC range according to the parameter values ​​corresponding to the input SOC, so that each SOC point has a corresponding state parameter. At the beginning of the simulation, the capacity of each cell and the initial SOC value should be determined. As the simulation proceeds, the SOC of the battery changes, and the component parameters also change accordingly. The branch current at each time point can be calculated by the polarization voltage at the previous moment and the component parameters at this moment, and finally the calculation of the branch current of the parallel battery pack and the simulation of various state quantities are realized.

[0096] The parallel model simulation results and the detected branch current are shown in Figures 7 to 9 Comparing the simulation results and the true value of the branch current of the parallel module, it can be seen that the relative error of the model is within 3%. Only at the end of charging, the relative error is large. This is due to the characteristic of the lithium iron phosphate battery that the voltage rises sharply at the end of charging. In general, the model can simulate the branch current of the parallel battery pack well.

[0097] From the above description, it can be seen that the parallel battery pack modeling method provided in the embodiment of the present invention adopts a second-order equivalent model of the battery in order to improve the accuracy of the simulation model, and the model parameters are obtained by the HPPC experiment; in view of the fact that the OCV change rate of the lithium iron phosphate battery in the low-end SOC and high-end SOC range is fast, resulting in a large current calculation error, the present invention adopts the OCV-SOC curve during 0.05C charging as the standard curve, which better improves this problem.

[0098] On the other hand, the present invention adopts linear interpolation method to obtain the state parameters of the battery in the full SOC range. The model can obtain the corresponding parameters of the battery through the current SOC state table lookup, and further complete the simulation calculation, thus solving the difficulty that the battery parameters change with the SOC in practice.

[0099] Finally, the present invention quotes the loop current matrix in the electrical network theory to calculate the parallel branch current, and combines the loop current method with the lithium battery state equation to solve it, eliminating the branch current collection link of the parallel battery pack; after the model calculates the branch current, the state of the battery module can be further estimated, and the impact of the branch unbalanced current on the safe operation of the module can be analyzed.

[0100] Based on the same inventive concept, the embodiments of the present application also provide a parallel battery pack modeling device, which can be used to implement the methods described in the above embodiments, such as the following embodiments. Since the principle of solving the problem by the parallel battery pack modeling device is similar to that of the parallel battery pack modeling method, the implementation of the parallel battery pack modeling device can refer to the implementation of the parallel battery pack modeling method, and the repeated parts will not be repeated. As used below, the terms "unit" or "module" can be a combination of software and / or hardware that implements predetermined functions. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0101] The embodiment of the present invention provides a specific implementation of a parallel battery pack modeling device capable of implementing a parallel battery pack modeling method, see Fig.10 , the parallel battery pack modeling device specifically includes the following contents:

[0102] A state equation generating module 10, used to generate a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack;

[0103] A state equation solving module 20, used for solving the state equation to generate a branch current solution of the parallel battery pack;

[0104] The battery pack model building module 30 is used to build a parallel battery pack model according to the branch current solution, and the parallel battery pack model is used to simulate the branch current of the parallel branch.

[0105] In one embodiment, see Fig.11 , the state equation generating module 10 comprises:

[0106] A single cell state equation establishing unit 10a, used to establish a second-order RC model and a state response equation of a single cell in the parallel battery pack;

[0107] The state equation generating unit 10b is used to generate the state equation of the parallel battery group according to the second-order RC model and the state equation of the single battery.

[0108] In one embodiment, see Fig.12 , the state equation solving module 20 comprises:

[0109] A current matrix establishing unit 20a, used to establish a loop current matrix of the parallel battery group;

[0110] The state equation solving unit 20b is used to solve the state equation according to the loop current matrix.

[0111] In one embodiment, the branch current solution includes: OCV, ohmic internal resistance and polarization parameters of the battery.

[0112] From the above description, it can be seen that the parallel battery pack modeling device provided in the embodiment of the present invention first generates the state equation of the parallel battery pack according to the equivalent model of the parallel battery pack; then, solves the state equation to generate the branch current solution of the parallel battery pack; finally, establishes the parallel battery pack model according to the branch current solution. The present invention can realize the calculation of the parallel branch current according to the performance parameters and state equation of the battery, and then estimate the state of the parallel battery pack, eliminating the detection link of the parallel branch current and simplifying the process; for large-scale parallel battery packs, since the computer is used to solve the equation, the solution speed and accuracy are greatly accelerated; at the same time, the parallel battery pack established by the present invention can be used for the analysis of unbalanced current in the parallel branch, providing a reference basis for the safe operation of the module.

[0113] The embodiment of the present application also provides a specific implementation of an electronic device capable of implementing all steps in the parallel battery pack modeling method in the above embodiment, see Fig.13 , electronic equipment specifically includes the following:

[0114] Processor (processor) 1201, memory (memory) 1202, communication interface (CommunicationsInterface) 1203 and bus 1204;

[0115] The processor 1201 , the memory 1202 , and the communication interface 1203 communicate with each other via the bus 1204 ; the communication interface 1203 is used to realize information transmission between relevant devices such as the server-side device, the power measurement device, and the user-side device.

[0116] The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, all steps in the parallel battery pack modeling method in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented: Figure 1 The following steps:

[0117] Step 100: Generate a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack;

[0118] Step 200: solving the state equation to generate a branch current solution of the parallel battery group;

[0119] Step 300: Establish a parallel battery pack model according to the branch current solution, wherein the parallel battery pack model is used to simulate the branch current of the parallel branch.

[0120] The embodiment of the present application also provides a computer-readable storage medium capable of implementing all the steps in the parallel battery pack modeling method in the above embodiment. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, all the steps in the parallel battery pack modeling method in the above embodiment are implemented. For example, when the processor executes the computer program, the following steps are implemented: Figure 1 The following steps:

[0121] Step 100: Generate a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack;

[0122] Step 200: solving the state equation to generate a branch current solution of the parallel battery group;

[0123] Step 300: Establish a parallel battery pack model according to the branch current solution, wherein the parallel battery pack model is used to simulate the branch current of the parallel branch.

[0124] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the hardware + program embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0125] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0126] Although the present application provides method operation steps such as embodiments or flow charts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in the embodiments is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order of the method shown in the embodiments or the drawings or in parallel (for example, in a parallel processor or multi-threaded processing environment).

[0127] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0128] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0129] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0130] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0131] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A parallel battery pack modeling method, characterized in that: include: Generate a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack; Solving the state equation to generate branch current solutions of the parallel branches of the parallel battery pack; Establishing a parallel battery pack model according to the branch current solution, wherein the parallel battery pack model is used to simulate the branch current of the parallel branch; The generating the state equation of the parallel battery pack according to the second-order equivalent model of the parallel battery pack includes: Establish the state equation and equivalent model of the single cell in the parallel battery pack, and verify its state equation based on the equivalent model of the single cell, and establish the equivalent model and state equation of the parallel battery pack on the basis of passing the verification; A parallel battery pack model is established according to the branch current solution, wherein the parallel battery pack model is used to simulate the branch current of the parallel branch, including: Solve the OCV, ohmic internal resistance and polarization parameters of the battery at the current moment, and finally iterate again to obtain the new branch current, and so on, and finally establish a parallel battery pack model.

2. The parallel battery pack modeling method according to claim 1, characterized in that: The generating the state equation of the parallel battery pack according to the second-order equivalent model of the parallel battery pack includes: Establishing a second-order RC model and a state response equation of a single battery in the parallel battery pack; The state equation of the parallel battery group is generated according to the second-order RC model of the single battery and the state equation.

3. The parallel battery pack modeling method according to claim 1, characterized in that: The solving the state equation comprises: Establishing a loop current matrix of the parallel battery pack; The state equation is solved based on the loop current matrix.

4. The parallel battery pack modeling method according to claim 1, characterized in that: The branch current solution includes: OCV, ohmic internal resistance and polarization parameters of the battery.

5. The parallel battery pack modeling method according to claim 1, characterized in that: The battery type in the parallel battery pack is lithium battery, and the number of the lithium batteries is 2 to 10.

6. A parallel battery pack modeling device, characterized in that: include: A state equation generating module, used for generating a state equation of the parallel battery pack according to a second-order equivalent model of the parallel battery pack; A state equation solving module, used for solving the state equation to generate a branch current solution of the parallel battery pack; A battery pack model building module, used to build a parallel battery pack model according to the branch current solution, wherein the parallel battery pack model is used to simulate the branch current of the parallel branch; The generating the state equation of the parallel battery pack according to the second-order equivalent model of the parallel battery pack includes: Establish the state equation and equivalent model of the single cell in the parallel battery pack, and verify its state equation based on the equivalent model of the single cell, and establish the equivalent model and state equation of the parallel battery pack on the basis of passing the verification; A parallel battery pack model is established according to the branch current solution, wherein the parallel battery pack model is used to simulate the branch current of the parallel branch, including: Solve the OCV, ohmic internal resistance and polarization parameters of the battery at the current moment, and finally iterate again to obtain the new branch current, and so on, and finally establish a parallel battery pack model.

7. The parallel battery pack modeling device according to claim 6, characterized in that: The state equation generation module comprises: A single cell state equation establishing unit, used to establish a second-order RC model and a state response equation of a single cell in the parallel battery pack; A state equation generating unit is used to generate a state equation of the parallel battery group according to the second-order RC model and the state equation of the single battery.

8. The parallel battery pack modeling device according to claim 6, characterized in that: The state equation solving module comprises: A current matrix establishing unit, used for establishing a loop current matrix of the parallel battery pack; A state equation solving unit is used to solve the state equation according to the loop current matrix.

9. The parallel battery pack modeling device according to claim 6, characterized in that: The branch current solution includes: OCV, ohmic internal resistance and polarization parameters of the battery.

10. The parallel battery pack modeling device according to claim 6, characterized in that: The battery type in the parallel battery pack is lithium battery, and the number of the lithium batteries is 2 to 10.

11. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the parallel battery pack modeling method according to any one of claims 1 to 5 are implemented.

12. A 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 parallel battery pack modeling method described in any one of claims 1 to 5 are implemented.

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