Here is tear-down view of the following USB charger:
SilverCrest SPBS 5000 B2
Battery: 3.7V 5000 mAh 18.5Wh
Input: 5V 2100 mA
Output: 5V 2100 mA
It was sold by LIDL. This device has a built-in battery that can be charged with other USB charger or with built-in solar panel.
Here is a video review of it:
Silvercrest Power Bank Solar Charger SPBS 5000 B2 TESTING
Let’s take a look what is inside because my USB charger does not work anymore and it is no longer under warranty:
The inside of this device looks in many details quite similar to the older USB charger sold by LIDL I repaired earlier.