| The maximum temperature difference allowed inside a nickel-hydrogen battery to avoid water relocation was calculated by a graphical method using the vapor pressure versus temperature correlation equation for water and potassium hydroxide solution. The equation for the maximum temperature difference allowed was developed for vessel wall temperatures between 0{dollar}spcirc C{dollar} and 30{dollar}spcirc C{dollar} and potassium hydroxide concentrations between 20% and 32%. The heat generation equation for the nickel-hydrogen battery was used to investigate the effect of the heat generation location on the maximum temperature and temperature distribution.; A thermal model of a multicell common pressure vessel nickel-hydrogen battery was developed. A finite element software package called PDE/Protran was used to solve this model. A differential energy balance equation was used as the governing equation. The physical and thermal properties of each cell region were averaged using the porosity. Conduction is assumed to be the only heat transfer mechanism in calculating the temperature behavior inside the cell.; The model was used to investigate the effects of various design parameters on the temperature profile within the cell. These parameters include the number of modules between heat fins, heat generation rate, heat fin geometry (thickness and height), and the heat fin material. The results were used to help find a design that will yield an acceptable temperature gradient inside a multicell common pressure vessel nickel-hydrogen battery. Steady state with constant heat generation rate, unsteady state with constant and pulse heat generation rate, and unsteady state with time dependent heat generation rate were also studied. |
