Issue link: https://resources.pcb.cadence.com/i/1480205
APPLICATION NOTE 9 N cell is simulated by changing the properties of the cell. The .IC statement sets the initial conditions, and must be set for every subcircuit used. V(X1.50) sets the initial charge on node 50 of the X1 subcircuit. This is the voltage on the battery Amp-hour capacity model which simulates the initial state of charge. Setting this node to 1 Volt equals an initial state of charge of 100%. Likewise, 0.8 Volts would represent an 80% initial state of charge. The next initial condition ( V(X1.60)=0) sets the voltage on the delayed lost rate calculator to zero. This allows the voltage on capacitor C1 (internal to the subcircuit) to start at 0 Volts as it would if the discharge current was zero before the simulation started. Another way to achieve this result is to switch on the discharge currents just after the simulation starts. This automatically sets the delayed lost rate voltage to zero at the start of the simulation. Note:To perform simulation of other cell models use the .olb file. Temperature Effects During a fast discharge, the cell temperature of a NICD can change by 25°C or more. The effect of cell temperature on voltage is accounted for in the NICD model by changing the cell voltage based on the calculated temperature. The other models do not incorporate temperature effects directly into the simulation. The major temperature influence on the cell is capacity. This may be accounted for by adjusting this parameter at the start of a simulation. The following equations give the new capacity for each cell type at any discharge temperature from 0 to 60°C based on the initial capacity at 25°C. 1.Alkaline Cells: NewCapacity = OldCapacity * (0.85 + 8.64E-3 * T - 1.05E-4 * T*T) 2.Nickel-Cadmium Cells: If T > 25°C NewCapacity=OldCapacity If T < 25°C NewCapacity=OldCapacity*(0.815+7.5E-3*T) 3.Nickel-Metal-Hydride Cells: NewCapacity=OldCapacity*(0.913+1.1E-2*T-3.0E-4*T*T) 4.Lead-Acid Cells: NewCapacity=OldCapacity*(0.84 + 7.96E-3*T-6.07E-5*T*T) To use the equations, simply plug in the 25°C initial capacity for OldCapacity and the new discharge temperature for T into the proper equation. If needed, these equations can also be built into the subcircuit models. Figure 6:Schematic for Alkaline AA Cell Discharge test