AN2344 Battery Charger With Cell Balancing - Eliminates Capacitors in BMS?

[Jddewitt83]

Hi,

I reviewed the datasheet associated with the AN2344 and noticed that on the Battery Pack Management System side there are no capacitors (pg. 2 of the attached datasheet). Is this accurate? The BMS appears to achieve the necessary balancing and cell protection on the battery assembly via MOSFET's and resistors. I'm hoping to receive confirmation that by using the AN2344 balanced charger that capacitors are not used in the battery assembly BMS. My application requires the presence of zero capacitors.

Any help will be greatly appreciated.

Joe DeWitt PE, PMP

[SampathS_11]

Hello @Jddewitt83 ,

In making a test sample for AN2344 Battery Charger With Cell Balancing, we did not use any capacitors, in parallel with the cells. You can observe that there are no capacitors in the schematics Figure 5, page 6. I hope that by capacitors you mean capacitors of sufficient energy storage to affect the cell energy significantly, and not just to suppress high frequency noise for measurement purposes.

These days, there are batteries with a wide variety of chemistries, and I suggest that you kindly check if the batteries you are working with, does not require capacitors for energy exchange in parallel with the individual cells of the battery.

Best regards,

Sampath Selvaraj

[Jddewitt83]

Hi Sempath,

Thank you for the response. Yes, my question is specifically geared towards the capacitors used on the battery cell voltage senses lines. I'm working on an intrinsically safe application and eliminating capacitors from the battery assembly BMS circuit will enable me to increase the current I can flow to the product while located in the hazardous location. I'm not concerned about any capacitors located within the charger BMS circuit as the charger would not be located in the hazardous location so that is a plus.

In reference to the BAT_CON connection in Figure 5, what I'm curious about is what the circuit would look like downstream of this connection as it relates to the BMS that would be located inside the portable battery assembly enclosure. Do you have a battery assembly BMS that can be used on the battery side in conjunction with your cell balancing charger AN2344? I ask this because I would imagine that I would still need under voltage and over discharge protection for example and this is where I'm wondering if capacitors would still be present even if cell balancing is performed by the charger BMS.

Best regards,

Joe DeWitt PE, PMP

[SampathS_11]

Hello @Jddewitt83 ,

Since this App Note was released long back, I am unable to trace any hardware that we used to the App Note. But from my memory, I can say that there were no capacitors on the battery which was used to test this App Note.

Best regards,

Sampath