CN103632018B - A kind of fuel cell modelling method based on Simscape platform - Google Patents

Abstract

The invention discloses a kind of fuel cell modelling method based on Simscape platform, comprise the following steps: parameter in equivalent-circuit model is extracted in HPPC test；Battery road state of cyclic operation degradation, every time test battery capacity and ohmic internal resistance after circulation；The each circuit module in equivalent-circuit model is set up based on Simscape platform；Cell submodel is set up according to each circuit module set up；Single battery submodel is set up in cell submodel parallel connection；Set of cells block mold is set up in the series connection of single battery submodel；Each cell submodel in set of cells block mold is carried out the setting of aging factor。The modeling accuracy of the present invention is higher than Electric Vehicle Simulation Software ADVISOR more common at present。Modeling method based on Simscape platform provides a kind of new thinking and method for modeling in the future, and it is simple that it has modeling, the advantages such as motility is strong。

Description

A kind of fuel cell modelling method based on Simscape platform

Technical field

The present invention relates to a kind of modeling method, particularly relate to a kind of fuel cell modelling method based on Simscape platform。

Background technology

Along with popularizing of electric automobile, safety problem increasingly causes the concern of people, the safety problem of electric automobile is the safety of electrokinetic cell after all, electric automobile power battery group is generally made up of multiple cells, inconsistent due to cell, overcharge causing some cell to occur in set of cells use procedure, cross the phenomenon put, cause the safety problem of electric automobile。

Electric automobile power battery group generally in parallel by multiple cells, be composed in series, due to the difference between different monomers battery, making the serviceability of set of cells well below the original level of cell, the difference between cell increased with the use time of set of cells。Due to the limitation of experimental enviroment and condition, emulation technology plays important role in the matching correct of electric automobile power battery。For this, forefathers propose multiple equivalent-circuit model, for instance Rint model, Thevenin model, PNGV model, RC model, GNL model etc.。In set of cells overall performance is studied, commonly used Matlab/Simulink platform is modeled analyzing, but Matlab/Simulink platform modeling needs to propose math equation according to physics law, building corresponding phantom further according to mathematical model, this seems loaded down with trivial details when carrying out parallel circuit, complicated circuit emulation。The application patent proposes the fuel cell modelling method based on Simscape platform。

The research cell difference impact on set of cells serviceability, has important theory significance and practical value to the serviceability improving electric automobile power battery group。

Summary of the invention

For solving the deficiency that prior art exists, the invention discloses a kind of fuel cell modelling method based on Simscape platform, the modeling accuracy of the present invention is higher than Electric Vehicle Simulation Software ADVISOR more common at present。Modeling method based on Simscape platform provides a kind of new thinking and method for modeling in the future, and it is simple that it has modeling, the advantages such as motility is strong。

For achieving the above object, the concrete scheme of the present invention is as follows:

A kind of fuel cell modelling method based on Simscape platform, comprises the following steps:

Parameter in the equivalent-circuit model under different battery temperature, battery current and battery SOC is extracted in step one: HPPC test, sets up the multi-dimensional table of each battery model parameter and battery temperature, charging and discharging currents, cell SOC；HybridPulsePowerCharacteristic and HPPC, battery charge state and Stateofcharge, abbreviation: SOC；

Step 2: battery road state of cyclic operation degradation, every time test battery capacity and ohmic internal resistance after circulation, obtaining battery capacity increases curve with circulating battery access times attenuation curve and battery ohmic internal resistance with circulating battery access times；Use along with battery, battery will appear from the phenomenon that capacity declines and ohmic internal resistance increases, this it is referred to as cell degradation, for more real simulating actual conditions, the aging conditions of battery is tested, increases curve with circulating battery access times attenuation curve and battery ohmic internal resistance with circulating battery access times obtaining battery capacity respectively；

Step 3: set up each equivalent circuit module in battery equivalent circuit model according to equivalent circuit theory based on Simscape platform；

Step 4: according to battery equivalent circuit model, each module in the equivalent-circuit model that integrating step three is set up, according to circuit catenation principle, each module is carried out electric rule connection, finally obtain cell model, cell model utilizes the function that platform carries set up cell submodule again, and the demarcation of cell submodel and checking utilize the multi-dimensional table of HPPC test foundation and the data of test；

Step 5: cell model parallel connection is obtained single battery model；Step 4 establishes cell submodule, the parallel connection of cell elder generation is generally obtained single battery by reality, therefore each cell submodule is also carried out parallel connection according to circuit catenation principle by model, to set up single battery submodule；

Step 6: set of cells block mold is set up in the series connection of single battery model；Establishing single battery submodule in step 5, in reality, general series connection by single battery obtains set of cells on electric automobile, therefore also according to circuit catenation principle, each only batteries submodule is connected in model, to set up battery pack model；

Step 7: each cell submodel in set of cells block mold is carried out the setting of aging factor。In step 2 already indicated above along with the use of battery, cell degradation, for more real simulated battery practical situation, to the given aging factor of cell each in set of cells block mold；Unavoidably there are differences between different monomers battery, these differences are also described by aging factor in a model。

Equivalent model parameter is including the open-circuit voltage in equivalent-circuit model, ohmic internal resistance, polarization resistance, polarization capacity etc., needing exist for according to concrete equivalent-circuit model determines to need to extract which model parameter, the extraction of equivalent model parameter is for Calibration Simulation model。

In described step one, battery equivalent circuit model includes open-circuit voltage model, ohmic internal resistance model, polarization resistance model, polarization capacity model。

In described step one, battery equivalent circuit model is single order RC equivalent-circuit model。Here it is only for single order RC equivalent-circuit model, is not limited only to this, can expand。

Each circuit module in described step 3, including open-circuit voltage module, resistive module, capacitance module, thermal module and SOC estimation block。

Described thermal module calculates cell internal temperature according to the power consumption of cell inside, and temperature computation principle adopts

$C_T{M}_{\mathrm{cell}}\frac{\mathrm{dT}}{\mathrm{dt}}=-A_{\mathrm{cell}}\frac{T-T_{\mathrm{amb}}}{R_T}+Q_{\mathrm{cell}}---\left(1\right),$

In formula, C_TFor specific heat capacity；T is internal temperature of battery；T_ambFor ambient temperature；R_TFor heat convection thermal resistance；Q_cellFor inside battery consumed energy；M_cellRepresent the quality of single battery；A_cellRepresent the heat convection area of single battery。

Described inside battery consumed energy comes from battery ohmic internal resistance and polarization resistance, shown in its computing formula such as formula (2): $Q_{\mathrm{cell}}=I^2{R}_0+I_1^2{R}_1---\left(2\right).$

Described SOC estimation block is used for estimating that set of cells entirety SOC, SOC estimation adopts ampere-hour integration method, and computing formula is as follows: $\mathrm{SOC}=1-\frac{Q_{\mathrm{con}}}{C}---\left(3\right),$

In formula (3), Q_conRepresent battery contents of decrement；C represents battery total capacity。

Relevant parameter is estimated by above-mentioned open-circuit voltage model, ohmic internal resistance model, polarization resistance model, polarization capacity model according to the use environment of cell, the present invention is according to the SOC of cell, battery current and temperature, by acquisition cell current open circuit voltage, ohmic internal resistance, polarization resistance, the polarization capacity of tabling look-up, then the correction of aging factor is carried out, it is thus achieved that the model parameter such as open-circuit voltage under present battery status, ohmic internal resistance, polarization resistance and electric capacity。

Above-mentioned open-circuit voltage model, the input value of ohmic internal resistance model, polarization resistance model and polarization capacity model is the currently used state of battery (including battery temperature, battery charging and discharging electric current and battery SOC), is output as model relevant parameter。Each model, by monitoring battery current state as input, then passes through the battery model parameter multi-dimensional table set up in step one, using the output as model of this checking result。What certainly present invention generally provides is a kind of modeling approach, method, and mode input has a variety of to the processing mode of output, and only one illustrates for example here。Because setting up, based on Simscape platform, the modeling process that model is a kind of sequencing, the foundation of model is all that program realizes。Above-mentioned model is output as each model parameter, including cell open-circuit voltage, ohmic internal resistance, polarization resistance and polarization capacity。Above-mentioned steps two has been proposed that and needs battery is carried out aging demarcation, to meet actually used situation。In step 2 already by Experimental Calibration the aging curve of battery, actually used process comprises in set of cells polylith cell, this model gives the recycling number of times of each cell at random by program, then pass through aging curve and obtain the aging factor of each cell, aging factor is multiplied with above-mentioned model output valve and obtains more real battery model parameter。

Beneficial effects of the present invention:

Through substantial amounts of experiment, the modeling accuracy of the present invention is higher than Electric Vehicle Simulation Software ADVISOR more common at present。Modeling method based on Simscape platform provides a kind of new thinking and method for modeling in the future, and it is simple that it has modeling, the advantages such as motility is strong。

Based on the battery model that Simscape platform is set up, in parallel, connect and can set up the integral battery door model of power battery pack, for research cell performance difference, the impact of all the other cells in set of cells is provided possibility。Theories integration is provided for electric automobile power battery safe handling。

Accompanying drawing explanation

Fig. 1 is the battery model schematic diagram that the present invention adopts；

Fig. 2 is that the present invention sets up battery model flow chart based on Simscape platform。

Detailed description of the invention:

Below in conjunction with accompanying drawing, the present invention is described in detail:

Accompanying drawing 1, for setting up, based on Simscape platform, the battery model schematic diagram that battery model adopts, the invention is not restricted to this battery model certainly, is merely illustrative for the ease of setting forth。E in figure_mFor battery open circuit voltage, R₀For the ohmic internal resistance of battery, R₁For the polarization resistance of battery, C₁For the polarization capacity of battery, it and R₁Constitute capacitance-resistance loop, for the dynamic characteristic of simulated battery。These have been carried out big quantity research by forefathers, it is believed that these parameters and battery SOC, temperature and to flow through it current related。Simultaneously forefathers are aging also by what experimental results demonstrate along with battery, R₀To increase and R₁It is basically unchanged。I represents the total current flowing through battery, I₁Represent and flow through polarization resistance R₁Electric current。

Parameter in the equivalent-circuit model under different battery temperature, battery current and battery SOC is extracted in HPPC test, sets up the multi-dimensional table of each battery model parameter and battery temperature, charging and discharging currents, cell SOC；Battery road state of cyclic operation degradation, every time test battery capacity and ohmic internal resistance after circulation, obtaining battery capacity increases curve with circulating battery access times attenuation curve and battery ohmic internal resistance with circulating battery access times；The each circuit module in equivalent-circuit model is set up based on Simscape platform；Setting up cell submodel according to each circuit module set up, the demarcation of cell submodel and checking utilize multi-dimensional table and the test data of HPPC test foundation；Single battery submodel is set up in cell submodel parallel connection；Set of cells block mold is set up in the series connection of single battery submodel；Each cell submodel in set of cells block mold is carried out the setting of aging factor。

The flow chart setting up battery model based on Simscape platform that accompanying drawing 2 proposes for the present invention。Model is set up and is divided into 7 stages。First stage is that the parameter in model is measured, and obtains the model parameter under different temperatures, electric current and SOC；To the battery eliminator Model Parameter measurement under different battery temperatures, battery current and battery SOC, set up the multi-dimensional table of each battery model parameter and battery temperature, charging and discharging currents, cell SOC；Second stage is model aging test, carry out Jinan road state of cyclic operation test, test capacity and the ohmic internal resistance of battery after difference circulates, cell degradation is tested, carry out the test of battery road state of cyclic operation, test battery capacity and ohmic internal resistance after circulation every time, obtain battery capacity and the ohmic internal resistance change curve with circulating battery access times, the first two stage is the collection carrying out data for the modeling of battery and the checking of model, demarcation and the checking of cell submodel provide data support, simultaneously for describing the offer data support of cell difference。Three phases is to set up each module in equivalent circuit, and this part is based on Simscape language, and the module of foundation is based on programming realization, and here for battery model, this modeling method can be extended to a lot of field in the future, is not limited only to battery model。Four-stage is based on each battery module of three phases foundation and sets up cell model, according to battery eliminator equivalent-circuit model, in conjunction with each module in the equivalent-circuit model that the phase III sets up, according to circuit catenation principle, each module is carried out electric rule connection, finally obtain cell model。The function that platform carries is utilized to set up cell submodule on cell model again。Cell parallel connection is obtained single battery model by the 5th stage, and the series connection of single battery model is set up battery cell model by the 6th stage。Establish cell submodule according in fourth stage, generally the parallel connection of cell elder generation is obtained single battery according in reality, each cell submodule is carried out parallel connection, to set up single battery submodule；6th stage established single battery submodule according to the 5th stage, according to general in reality, single battery series connection is obtained set of cells on electric automobile, therefore is connected by each single battery submodule, sets up battery pack model。Owing to the state of the last cell of electric automobile can not be identical, owing on electric automobile, there are differences between catabiosis and each cell occurs in increase battery along with access times；Therefore in battery pack model cell submodel is carried out the setting of aging factor by a cell aging factor in the last stage given battery pack model at random。When battery pack model is set up complete, utilize the battery pack model set up, it is possible to the research inconsistent impact on set of cells entirety serviceability of cell and the impact on other any cell performances。Certain present invention is intended merely to and sets forth the flow process conveniently giving a kind of modeling, the present invention having been proposed that, the modeling method based on Simscape platform has and models feature flexibly, different in a practical situation cell degradation degree, use under environment and mode of operation, the parameter of battery is different, for more accurate artificial battery group performance, can combine with mode identification technology, on-line identification model parameter, the model parameter of acquisition is used for the demarcation of phantom。

Claims (6)

1., based on a fuel cell modelling method for Simscape platform, it is characterized in that, comprise the following steps:

Parameter in the equivalent-circuit model under different battery temperature, battery current and battery SOC is extracted in step one: HPPC test, sets up the multi-dimensional table of each battery model parameter and battery temperature, charging and discharging currents, cell SOC；

Step 2: battery road state of cyclic operation degradation, every time test battery capacity and ohmic internal resistance after circulation, obtaining battery capacity increases curve with circulating battery access times attenuation curve and battery ohmic internal resistance with circulating battery access times；

Step 3: set up each equivalent circuit module in battery equivalent circuit model according to equivalent circuit theory based on Simscape platform；

Step 4: according to battery equivalent circuit model, each module in the equivalent-circuit model that integrating step three is set up, according to circuit catenation principle, each module is carried out electric rule connection, finally obtain cell model, cell model utilizes the function that platform carries set up cell submodule again, and the demarcation of cell submodel and checking utilize multi-dimensional table and the test data of HPPC test foundation；

Step 5: cell model parallel connection is obtained single battery model；

Step 6: set of cells block mold is set up in the series connection of single battery model；

Step 7: each cell submodel in set of cells block mold is carried out the setting of aging factor；

The model parameter in battery equivalent circuit model in described step one includes open-circuit voltage, ohmic internal resistance, polarization resistance and polarization capacity；

The open-circuit voltage model that above-mentioned open-circuit voltage, ohmic internal resistance, polarization resistance and polarization capacity are corresponding, the input value of ohmic internal resistance model, polarization resistance model and polarization capacity model is the currently used state of battery, including battery temperature, battery charging and discharging electric current and battery SOC, it is output as model relevant parameter, each model is by monitoring battery current state as input, then pass through the battery model parameter multi-dimensional table set up in step one, using the output as model of this checking result。

2. a kind of fuel cell modelling method based on Simscape platform as claimed in claim 1, is characterized in that, in described step one, battery equivalent circuit model is single order RC equivalent-circuit model。

3. a kind of fuel cell modelling method based on Simscape platform as claimed in claim 1, is characterized in that, each circuit module in described step 3, including open-circuit voltage module, resistive module, capacitance module, thermal module and SOC estimation block。

4. a kind of fuel cell modelling method based on Simscape platform as claimed in claim 3, is characterized in that, described thermal module calculates cell internal temperature according to the power consumption of cell inside, and temperature computation principle adopts

$C_T{M}_{cell}\frac{dT}{dt}=-A_{cell}\frac{T-T_{amb}}{R_T}+Q_{cell}---\left(1\right),$

In formula, C_TFor specific heat capacity；T is internal temperature of battery；T_ambFor ambient temperature；R_TFor heat convection thermal resistance；Q_cellFor inside battery consumed energy；M_cellRepresent the quality of single battery；A_cellRepresent the heat convection area of single battery。

5. a kind of fuel cell modelling method based on Simscape platform as claimed in claim 4, is characterized in that, described inside battery consumed energy comes from battery ohmic internal resistance and polarization resistance, shown in its computing formula such as formula (2):

$Q_{cell}=I^2{R}_0+I_1^2{R}_1---\left(2\right);$

Wherein, R₀For the ohmic internal resistance of battery, R₁For the polarization resistance of battery, I represents the total current flowing through battery, I₁Represent and flow through polarization resistance R₁Electric current。

6. a kind of fuel cell modelling method based on Simscape platform as claimed in claim 3, is characterized in that, described SOC estimation block is used for estimating that set of cells entirety SOC, SOC estimation adopts ampere-hour integration method, and computing formula is as follows:

$SOC=1-\frac{Q_{can}}{C}---\left(3\right),$

In formula (3), Q_conRepresent battery contents of decrement；C represents battery total capacity。