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Feedback on Passthrough Charging Circuit

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DiscoD2682:
I'm working on a robotic car project that I want to run off of lithium batteries that charge off of USB-C. I'm a programmer that doesn't do electronics often and wanted feedback on the power circuit for it. I'll need to draw up to 5-6A at 5V at peak. I also need the car to still be powered when plugged in as it has other capabilities beyond movement (and will have a software mechanism to disable the drive motors so it doesn't drive off while charging). While plugged in, I also want the battery to charge even if the car is on.

Could anyone who has the time take a look at the attached circuit diagram to power the project off of USB-C when available and fallback to an internal battery pack and inspect for safety / other issues?
If there's a simpler solution that still provides the necessary amperage, please let me know.

The batteries are Samsung 50S 21700 cells (5000 mAh, 25A max output)

Battery datasheet: https://cdn.shopify.com/s/files/1/0481/9678/0183/files/INR21700-50S__Cell_Specification_V0.2_200911.pdf?v=1654906866

(Because I need to draw more than most cheap buck converters like the LM2596 can provide, I may end up using multiple buck converters to power separate motor controllers).

Also, I'm open to suggestions as to alternatives for the TP5100, but for now am going with it as I need to get the parts shipped quickly.

Thanks

ledtester:
You should also be able to get away with removing the diode on the right and adding a connection from the unused relay contact to the charging + terminal if your system can tolerate a slight interruption in power when the relay switches over.

DiscoD2682:

--- Quote from: ledtester on June 16, 2024, 04:18:41 am ---You should also be able to get away with removing the diode on the right and adding a connection from the unused relay contact to the charging + terminal if your system can tolerate a slight interruption in power when the relay switches over.

--- End quote ---

Thanks so much!! I'd been trying to get rid of that diode with no success, but that makes total sense. If I added a suitably large capacitor just before the buck converter, could that alleviate the power interruption problem?

Peabody:
Would you consider doing it with mosfets?  That would eliminate the switching glitch, and might be smaller and cheaper, and longer lasting, than the relay.

Edit:  It seems the circuit below might work.  They are P-channel mosfets.

Peabody:
Perhaps the OP has answered his questions, but could someone confirm whether my circuit in the post above would work in place of the relay?  It requires that USB voltage be at or above battery voltage.

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