Battery Analysis

 

Time Dependent Performance Analysis

Experimental Work    

Analytical Work

Inputs:  Cell Electrochemical Voltage, Total Cell Capacity, Resistances, Time Step, Load Resistance for Time Step

Outputs:  Actual Cell Voltage and Current Produced at Load Resistance, Total Power Capacity Constraint Violation Flag

Experimental Work

                    Experimental Setup

  • Manufacturer data was supplied for single cell discharge characteristics

  • The RC aircraft will discharge an entire pack of batteries in less than 10 minutes

  • The batteries were tested in a high energy consumption environment

  • Light bulbs were used in parallel

  • About 500 Watts going through these light bulbs

                Experimental Data

Battery Test 1- slow charge

Analytical Work

                    Data from Sanyo

                Theory/governing Equations

  • Use basic electronics equations
    • V=IR
    • P=IV
    • Kirchov's Law:  
      SV = 0, SI = 0
  • Combined with Mesh Analysis
  • •Rp and Rs are battery constants
  • Rload is known from the motor
  • V's are known from "cell history"
  • Must solve for current (i's)

We modeled battery cells as 10 “elements”, creating 10x10 matrices

                    Solution 

Each cell “element” produces a voltage as a function of the remaining energy in the cell

 

                    Comparison to Experimental Data