Cell balancing

NOTE: I have already designed the models, the only problem is i am not getting the proper results. I need help in redesigning it. Cell Balancing The batteries consists of many cells connected in series. Each cell has its own capacity and internal resistance which causes each cell to accept different amount of charge during charging as well as discharging. Here the problem arise of cell balancing. Means to say, during charging procedure, each cell should have the same amount of charge in order to utilize the full capacity of cell. The thing we have to do is first of all to model the lithium ion battery in matlab (you may get help from matlab help). Then using this model, we have to implement a technique called passive cell balancing to balance cell. Passive Cell Balancing In this type of technique, a cell with higher state of charge (SoC) dissipate the heat through resistor until its SoC becomes equal to other cell connected in series. You can see it in figure. A switch (MOSFET switch) is connected in series with the resistor. A switch will close when it sense the higher SoC and will dissipate the extra charge through resistor. Summary: First we have to make design of lithium ion battery model into MATLAB. I will give you a presentation about this which may help you a lot. (Open circuit voltage, state of charge, battery parameters R,C should be include) Next, using that lithium ion battery model, we will first apply the passive charge balancing (As I state above that passive balancing is that balancing in which a cell with higher SoC dissipate its energy through resistor till its voltages becomes to other battery voltage) and we might except the graph as follow: - In the figure, you can clearly see the SOC (State of charge of 4 cells). In the beginning of the time, each cell has different SoC, but during charging and applying passive balancing each cell equalize its SoC. Hop you have got some idea of what we are going to do. The last thing we need to do is applying active balancing. I will provide you some notes which will help you a lot for applying this. Note: We have to consider FOUR cells for this assignment. Active Balancing: Active balancing is unlike the passive balancing. A cell with higher SoC will gives its extra energy to cell with lower SoC. After active balancing we may expect the following graph. As it is clear from the figure that a cell with higher SoC (Green) is slightly discharge its self to give energy to Lower SOC cell. At the end, we have to merge both technique, If(SoC difference of cells is greater than 10%) Use Active Balancing Else if(SoC difference of cells is greater than 10%) Use Passive Balancing