Charging batteries with a PCB Charger
How you connect the battery depends on the charger used.
The example image that you give probably shows connection to a battery management system which as well as charging provides protection against over voltage, undervoltage and over current discharge operation. This is a very common method of connection and is recommended.
I acquired a number of multiple cell Liion battery packs produced by a major vacuum cleaner manufacturer (D----) which had no means of balancing cells. They suffered an early death - as should have been wholly expected by the &quot;designer&quot;,
Note that LiIon cells usually are rated at 4.2V fully charged with 3.6 or 3.7 V representing the mean voltage during discharge.  The 4 cell battery MUST be charged with a properly designed charger if it is not to die an early and possibly flaming death.