No, it's not. From the link I posted (in Dutch unfortunately, I'll translate the relevant bit):

Small integrated battery:

    3.5 kWh
    Starting at about € 2.100,-

You yourself indicated in your post that integrated batteries (as in: the ones with battery management, that you can actually use to store energy in as opposed to a bunch of lose cells) are more expensive. They are more expensive indeed. I did the calculation. They boil down to 0,12 EUR / kWh in the example above.

The price of cells is not directly relevant, since you can't actually buy cells and just throw them at your house to magically start charging/discharging when you desire.