calculate the battery voltage

my model using equivalent circuit of the battery

I would like to calculate the voltage of the battey

I see the equation of the voltage in

https://www.mathworks.com/help/sdl/ref/batterysystemlevel.html

where the voltage depend on SOC and beta

in this link define beta as

• β is a constant that is calculated so that the battery voltage is V1 when the charge is AH1. Specify the voltage V1 and ampere-hour rating AH1 using block parameters. AH1 is the charge when the no-load (open-circuit) voltage is V1, and V1 is less than the nominal voltage.

I would like to know how can I calculate β to get the voltage

thanks a lot in advance

Answer 1

[Shivam Gothi]

hello @MAB,

As per my understanding, you are trying to understand the calculation of term β, appearing in the equation of battery modelling, as stated in the documentation.

β is a constant that is used to model a battery with "finite" charge capacity. Open the block parameters for "battery" by double clicking on it. Change the "Battery Charge Capacity" property to "finite". This will prompt you to enter additional parameters as shown in the below figure:

According to the documentation, the β is calculated using the values of (V1, AH1, battery capacity, rated voltage) entered by the user. This is shown below:

now, take the β to the LHS to get its closed form expression:

The above equation is used to calculate the "β".

I hope this helps !

[MAB]

thanks alot for your response

my model use equivalent circuit of battery as shown in attached figure

I am not use the generic battery in matlab simulink

the last equation which you write has 2 unknow variable β and V1

I would like to calculate V1, so I want to know what the value of β

[Shivam Gothi]

hello @MAB,

The variables (AH1, V1Ah and Vo) are entered by the user based on the specifications of the battery to be modelled.They are not to be "calculated" . You can find them by refering to the datasheet of the battery provided by the manufacturer.