batteries - How determinate parameters for thermal-model battery (Advanced question about battery modelling)

I'm trying to simulate an electrical model based on Ceraolo battery model for lead-acid battery. The challenge in this model is to determine the parameters that describe it.

I can understand and estimate most of the parameters. However, it is still unclear to me how the parameters $Ke$ described in the paper.

The problem in this case is that the equation used to define $Ke$ uses the value of $Em$ which is not a value obtained via lab tests.

For those who know and understand the model, it is known that $Em$ is the voltage source responsible for emf at the "beginning" of the circuit in question, while Figure 4 represents the voltage at the battery terminals (i.e at the "end" of the circuit). It is for this reason that I believe that it is not possible to use the test values ​​to set the $Em$, since the test values ​​already show the terminal voltage of the battery.

The equation I'm talking about:

$E_m=E_{m0}-K_E(273+\theta)(1-SOC)$

Figure 4

The table with the voltage values corresponding to Figure 4

$$\begin{array}{|c|c|c|c|c|c|c|c|c|c|} \hline Battery & V_0[V] & V_1[V] & V_2[V] & V_3[V] & V_4[V] & \theta_{end} & I[A] & t[h] \\ \hline Battery\ 1 & 2.165 & 1.965 & 2.06 & 1.790 & 1.890 & 26 & 58 & 8.494\\ \hline Battery\ 2 & 2.115 & 1.995 & 2.01 & 1.788 & 1.905 & 26 & 63 & 7.197\\ \hline \end{array}$$

The parameters that Ceraolo obtained from these data were

$$\begin{array}{|c|c|c|} \hline Battery & E_{m0}[V] & K_E[mV/°C] \\ \hline Battery\ 1 & 2.165 & 0.782 \\ \hline Battery\ 2 & 2.115 & 0.832 \\ \hline \end{array}$$

It is easy to realize that the value of $E_{m0}$ can be obtained directly from the tests, but for those who will have patience, how will I get the value of $Ke$ if it is not possible to get $E_m$ through test labs ?

I think I have provided all the necessary information for the doubt. If you need anything else please let me know. The article is attached at the beginning of the post.