**TYPE47 : Battery **

**General Description**

The battery type is the same as the one described in the TRNSYS manual except for an addition of self discharge and a change in parameter input. The parameters have been divided in two groups; a group that describes the battery cell (specific for the type of battery) and another group that describes the setup of the batteries. The first group of data is given in a data file and this will make it possible to select different batteries from a data base.

The self-discharge model is implemented at Fraunhofer Institute in Freiburg, Germany by Wilfred Griesshaber and Fredrick Sick.

**Nomenclature**

- a - Factor for temperature and voltage
- b - Factor for temperature and voltage
- I
_{0sd}- Self discharge current at T = T_{0}and U = U_{0} - Q - Capacity of battery (Ampere hours)
- Q
_{max}- Maximum capacity of battery - T - Battery temperature
- T
_{0}- Temperature for I = I_{0sd}and U = U_{0} - U - Battery voltage
- U
_{0}- Voltage for I = I_{0sd}and T = T_{0} _{}

**Mathematical Description**

The mathematical equations used are the same as in the TRNSYS manual except the self discharge model:

The self discharge is calculated from this equation:

Isd = I0sd * Q/Qmax * e^{[a(T-T0) + b(U-U0)]}

^{}

**TRNSYS Component Configuration**

__PARAMETER NO.__ __DESCRIPTION__

- 1 mode - mode for calculations (all modes need the battery data even if the data are not needed).
- 2 lud - Logical unit number for the battery data base
- 3 C
_{p}- Cells in parallel - 4 C
_{s}- Cells in series - 5 N
_{batt}- Number of the selected battery in the data base - 6 T
_{batt}- Surrounding temperature of the electrolyzer - 7 V
_{c}- Maximum charge voltage - 8 V
_{contr}- <0 => V_{d}is calculated - >0 => V
_{d}= V_{contr} - 9 I
_{ctol}- Iteration accuracy in Ampere

__INPUT NO.__ __DESCRIPTION__

The inputs are the same as in the TRNSYS manual

__OUTPUT NO.__ __DESCRIPTION __

The outputs are the same as in the TRNSYS manual except four more outputs:

- 13 I
_{sd}- Self-discharge current - 14 Q
_{sd}- Self discharge ampere hours - 15 P
_{sd}- Self-discharge power - 16 P
_{wfull}- Power wasted because the battery is full.

The data for a battery cell has to be given in a separate file. The first line in this file will give the number of battery cells given in the file. The for each different cell will have two lines; the first line will give the number of the cell in the file, the second line will give the data for the cell. The last three parameters in the file have to be given even though the mode does not require it. It does not matter what values they are given in this case. The data file for the battery cell will be like this (the third line (P1-P18) should not be in the file, but are included here to show which data means what):

- 1,Batterycell
- 417 .9 2.5 29.3 2.00 1.18 .1 .1 1. -.0087 20. .1 2.07 2.13 2.2 0.0834 417 -417
- P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 P15 P16 P17 P18

- P1 = Q
_{max}: Rated capacity of battery cell [Ah] - P2 = Eff : Charging efficiency
- P3 = i
_{1}: Parameter used to calculate the additional voltage term from a given current in the Hyman model - P4 = k
_{1}: Parameter used to calculate the additional voltage term from a given current in the Hyman model - P5 = m
_{d}: Cell type of parameters which determine the shape of the I-V-Q characteristics for discharging - P6 = c
_{d}: Factor for capacity parameter on discharge [-] - P7 = s
_{d}: Factor for internal resistance at full charge for discharge [-] - P8 = g
_{d}: Coefficient of (1-F) in voltage formulas for discharging - P9 = m
_{c}: Cell type of parameters which determine the shape of the I-V-Q characteristics for charging - P10= c
_{c}: Factor for capacity parameter on charge [-] - P11= s
_{c}: Factor for internal resistance at full charge for charge [-] - P12= g
_{c}: Coefficient of (1-F) in voltage formulas for charging - P13= e
_{sd}: Extrapolated open circuit voltage for discharge - P14= e
_{sc}: Extrapolated open circuit voltage for charge - P15= U
_{0}: Basic voltage for self-discharge [V] - P16= I
_{0sd}: Self-discharge-current [A] at tbat=temp0(=20 C) and v=volt0 (2.2 V for lead-acid battery) - P17= I
_{Qmax}: Maximum current (charge) [A] - P18= I
_{Qmin}: Minimum current (discharge) [A]

OUTPUT to file logical unit 6 will look like this:

- Parameters from file to battery, unit xx:
- Qmax = 4.1700E+02 Eff = 9.0000E-01 i1 = 2.5000E+00
- k1 = 2.9300E+01 md = 2.0000E+00 cd = 1.1800E+00
- sd = 1.0000E-01 gd = 1.0000E-01 mc = 1.0000E+00
- cc = -8.7000E-03 sc = 2.0000E+01 gc = 1.0000E-01
- esd = 2.0700E+00 esc = 2.1300E+00 volt0 = 2.2000E+00
- I0sp = 8.3400E-02 IQmax = 4.1700E+02 IQmin = -4.1700E+02