Switching between two completely independent circuits
simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. OP's proposal redrawn.

With SW1 in position shown BAT2+ will be shorted to U1's BAT- which according to the TP4056 datasheet is supposed to be connected to ground so the arrangement is likely to have a very unhappy ending.







simulate this circuit

Figure 2. A circuit with less potential problems. SW1 is a 3-pole switch. 


SW1b and 1c allows switching of BAT1 in series with BAT2 or in parallel with U1.
SW1a prevents BAT2 receiving charge while BAT1 is disconnected.