Is it possible to speed up Battery simulations with power converters in Simulink?
As long as you didn't post your model, it is not possible to know what exactly your problem. However, here are some suggestions to make your simulation faster:


Remove all unnecessary Scopes/To workspace blocks or any kind of blocks that save data. You can comment them (Ctrl+Shift+x) if you want to use them in future. But recording too much information slow down your simulation significantly. So you just record the data that is important.
From Powergui block. Be sure that you are not over sampling your simulation. In other words, don't put sampling time unreasonably low (for example some people tend to put 1e-8 or even 1e-9 to capture fast dynamics in the simulation which is completely wrong). In your case, for example, switching frequency is \$25 kHz\$, which is equivalent to switching time of \$40 \mu s\$. So sampling time in range of \$ [4-10] \mu s\$ is fairly acceptable.
Change the solver (Ctrl+E). Sometimes changing the solver speed up the simulation significantly. I am not sure which solver is the best for your case, but it worth to try.


Update

It is all about sampling frequency. If you change the simulation type to discrete and simulation time to 1e-5 s in this simulation, it will also take long time. As @DanMills has mentioned in his answer, you have to know what you want from your simulation. If you want to study "converter/controller dynamics" then you don't need to run simulation for long time, few seconds are enough. If battery aging is important, then why to have very high switching frequency which lead to very low sampling time? You can simply reduce the switching frequency to (5 kHz) or less for example, i.e. sampling time 5e-5 s, which allows you to speed up your simulation more than 5 times without loosing the main goal of studying the battery dynamic. But obviously don't forget to change the converter parameters as the switching frequency is changed.