Powergraphy Battery Simulator Evaluation version 1.00 1. INTRODUCTION 1 1.1. WHAT DOES THIS PROGRAM DO? 1 1.2. HOW DOES IT WORK AND HOW EXACT IS THE PREDICTION? 2 1.3. WHAT CAN YOU DO IN ADDITION USING COMMERCIAL VERSION OF THE PROGRAM 2 2. INSTALLATION 3 3. "STEP-BY-STEP" GUIDE 3 4. ANALYSIS DETAILS 4 4.1. CONSTANT CURRENT 4 4.2. VARIABLE CURRENT 4 4.3. CONSTANT LOAD 5 5. WHAT CAN GO WRONG? 6 1. Introduction 1.1. What does this program do? Powergraphy battery simulation demo can calculate voltage profile during battery discharge/charge under user-defined conditions. That means for example, instead of measuring battery discharge profile using battery cycler (expensive and time consuming way) you can simply calculate it, which usually takes about 30 second. You can see how long the battery will power specific device until it fails, or optimize charging conditions. Basically, you can make any experiment with this virtual battery as if you had a real one in your hand, but without danger that would kill your device or any explosion. Demo includes constant current discharge/charge, variable pulse current discharge/charge and constant load discharge. Currently the number of battery is restricted to 4: Sony Li-ion 18650, Matsushita Li-ion 18650, Hitachi Ni-MH AA size and Duracell Alkaline AA size. 1.2. How does it work and how exact is the prediction? Numerical image of battery (NIOB) is not a collection of different discharge curves etc. Instead, it is a working mathematical model of battery. During the calculation, real processes inside the battery are recreated inside your computer. This model is based on deep understanding of battery's electrochemistry, supported by several scientific publications [ see end of page ]. Important point is that alkaline battery has different behavior from NiCd, even if both are AA size and can be plugged in same device. Moreover, even batteries of the same type (alkaline, NiCd, NiMH, Lead acid or Li-ion) can be very different. That is why characteristic parameters for each particular model of battery are obtained using an automatic Powergraphy battery parameterization system. More details about Powergraphy battery parameterization initiative can be found in http://www.kkpcr.re.kr/powergraphy. Precision of the simulation is proved by comparison of predicted voltage profiles with really measured ones, and in most cases does not exceed 2%. 1.3. What can you do in addition using commercial version of the program Commercial version of the program can be obtained from Korea Kumho Petrochemical Co., Ltd.. Check Powergraphy web site about the ordering procedure or contact us under following address: (coyoon@mail.kkpcr.re.kr) The commercial version of simulation software can simulate any kind of battery (provided you have a numerical image of the battery, produced by Powergraphy system, downloaded from battery manufacturer web site). It also has a database including many of popular battery models. The conditions of simulation are almost unlimited. In addition to many predefined conditions (including, for example, calculation of Ragone-plot, pulse discharge, constant and variable power discharge, DC motor discharge simulation etc.) you can even simulate the behavior of your entire device (Notebook, Mobile phone or electric vehicle) without even making it first ? using only its schematics. Several batteries can be put together to form a battery pack. Additional electric elements can be added to simulate the behavior of battery-pack safety device. Several different charge/discharge patterns can be applied to battery one after another, just as the battery cycler can do. You can however design loads, which will be very difficult if not impossible to measure experimentally, for example different fault conditions, including short circuiting batteries or malfunctioning one of the batteries in the pack. Another advantage of commercial version is possibility to visualize processes going on inside your battery. During the simulation, the entire information (currents, voltages, heat development) about any place inside the battery is available. You can actually see the diffusion concentration profiles and voltage distribution across the batteries active layer, notice where high current might pose a problem and where battery can still be pushed harder. 2. Installation Open the zip-archive in a temporary directory and run setup.exe. After finishing the installation remove all files in this temporary directory, except for this readme file which contains additional informatin not present in Help and therefore is usefully copied in program directory. Notice - 1024/743 is the screen resolution for which this program is designed. If resolution is lower, program will be larger then the screen. Otherwise on computers slower then k6-2 300 or Pentium-II 300 the simulation can take longer time then suggested in Help. 3. "Step-by-step" guide After starting the "Powergraphy battery simulator" program you can select a battery model by pressing a "Battery model selection" button. Select battery from the list and press "OK". From "Analysis" menu you can select analysis you want to perform. Only "Basic" analyses are available in demo version. Chose one of "constant current", "variable current" or "constant voltage" analysis. After adapting the analysis options for your needs, press "Run analysis" button. It is particularly important to set correct starting voltage. It usually should be equal to battery maximal voltage or less. Battery maximal voltage is shown in battery description line on Graph caption. Progress of analysis is approximately shown by "progress indicator" on program window. Analysis takes about 30 seconds, depending on discharge time you specified. When analysis is finished, battery voltage vs. time dependence is shown in the Graph window. It can be printed by choosing "Print" command in "File" menu. Voltage vs. time data is saved in program directory as ASCII file named "Analys.fig". 4. Analysis details 4.1. Constant current During this analysis battery is subjected to constant current discharge/charge. Available options are: - Current value Current at which battery is discharged or charged. Positive current means discharge of battery. - Battery's voltage Initial voltage of battery when discharge or charge is started. Good value is the one specified in "battery description line", or lower. Actual battery voltage will change during the discharge corresponding to calculation of internal electrochemical processes. - Duration of analysis Time interval during which the current is applied to battery - Time step Minimal time step which programs make during calculation. Actual time step used for printing of results is chosen adaptively and can be larger, if discharge profile is smooth. 4.2. Variable current During this analysis battery is subjected to complex current waveform specified by user. Available options are: - Current waveform pattern is defined by a table, where each row specifies "time" and "current" for each key-point of user-defined waveform. Current between the points is linearly interpolated, which means that on current vs. time plot each specified point would be connected by straight lines. User can change the default values arbitrary to match the intended analysis. "Time" should always increase from first to last point, whereas "Current" is arbitrary ? it can be negative, positive or zero (positive current means discharge). Last specified point should have time value equal to duration of analysis. Several points can have same time value, which would disable all of them but one. - Battery's voltage Initial voltage of battery when discharge or charge is started. Good value is the one specified in "battery description line", or lower. Actual battery voltage will change during the discharge corresponding to calculation of internal electrochemical processes. - Duration of analysis Time interval during which the waveform is applied to battery and voltage response is calculated. - Time step Minimal time step which programs make during calculation. Actual time step used for printing of results is chosen adaptivelly and can be larger, if discharge profile is smooth. 4.3. Constant load During this analysis battery is discharged through a constant resistor. Available options are: - Resistor value Value of the resistor connected to the battery. Usual battery powered devices have values from 10 to 100 Ohm. For example, a DC motor used in toy-train has resistance 20 Ohm, and pocket radio ? about 60 Ohm. Set value smaller then 0.1 Ohm to observe a short-circuit discharge of battery. - Battery's voltage Initial voltage of battery when discharge or charge is started. Good value is the one specified in "battery description line", or lower. Actual battery voltage will change during the discharge corresponding to calculation of internal electrochemical processes. - Duration of analysis Time interval during which the waveform is applied to battery and voltage response is calculated. - Time step Minimal time step which programs make during calculation. Actual time step used for printing of results is chosen adaptively and can be larger, if discharge profile is smooth. 5. What can go wrong? Under some unusual load conditions you might experience non-convergence problem during analysis. In this case Graph will not show all specified time region or show nothing at all. First check in this case, if conditions you specified make sense: - is "initial voltage" equal or lower then maximal voltage? - Is "simulation time" not too much longer then expected time of full discharge or charge of battery? Try reducing the "simulation time". If this checking still does not help, try reducing the time step to 0.1 or 0.01. References E. Barsoukov, J. H. Kim, C. O. Yoon, H. Lee, Solid State Ionics, 116, 249 (1999). E. Barsoukov, J. H. Kim, D. H. Kim, K. S. Kim, C.O. Yoon, H. Lee, J. Power. Sources, 83, 61 (1999). E. Barsoukov?, J. H. Kim, D. H. Kim, K. S. Hwang, C. O. Yoon, and H. Lee, Journal of New Materials for Electrochemical Systems, (1999) in press Copyright Program is copyright by Kumho Chemical Lab., Kumho Petrochemical Ltd. 1999 Distribution of unchanged program package is free and encouraged. Distribution of disassembled or changed by any means program package is prohibited and will be a subject of legal action. Program is distributed _as is_, user takes whole responsibility of any possible damage which might arise from using this program. Kumho Petrochemical will not by liable to any extent for any kind of damage arising from use of this program. Using simulation results in publications, presentations, web-sites and books is allowed as long as use of the program is acknowledged as follows: "Powergraphy Battery Simulator developed in Kumho Chemical Lab., Kuhmo Petrochemical Ltd."