BQ34110: Design Query regarding BMS integration and compatibility

Art Mecina

Part Number: BQ34110
Other Parts Discussed in Thread: BQ40Z80, BQ34Z100-G1, BQ25792, BQ76930, BQ76940, BQ76942, TIDA-010030

Hello Guys,

Good day.

Our customer is building a smart battery-operated car.

They're using NCR18650 Panasonic Batteries in a 6S configuration with BMS.

Please find below the link for both parts.

BMS: https://dalyelec.en.made-in-china.com/product/UNTmoKZVrShi/China-Li-ion-6s-24V-15A-Lithium-Battery-Protection-Board-with-Balance-PCM-BMS.html

Battery Datasheet: https://www.batteryspace.com/prod-specs/NCR18650B.pdf

They have selected the BQ34110 part as per their requirement but in the datasheet, BMS integration is not mentioned.

Their BMS is providing negative side regulation.

Can they use this Fuel Guage with Negative side BMS?

Can he place the RSENSE resistor positive side of the battery other than as shown in datasheet?

Thanks and regards,

Art

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105800 points

Hello Art,

I'm not sure I understand their requirements, the gauge must measure the current on the bottom of the stack, the sense resistor separates the system GND from the battery GND.

Sincerely,

Wyatt Keller

0 Art Mecina over 4 years ago in reply to Wyatt Keller

TI__Genius 16655 points

Hello Wyatt,

Good day.

According to the customer, they are looking for Battery Protection, Fuel Gauge, Charging and Balancing solution for 6S li-ion battery pack for his project.
He's using NCR18650B Panasonic Batteries with 1.6Amp CC-CV Charging pattern.

Any good suggestion?

Thanks and regards,

Art

0 Wyatt Keller over 4 years ago in reply to Art Mecina

TI__Guru** 105800 points

Hello Art,

The only gauge we offer for 6S support with protections and cell balancing is the BQ40Z80. Otherwise they will need to only use the gauge (like BQ34Z100-G1 or BQ34110) with a monitor or other protection/cell balancing device.

Sincerely,

Wyatt Keller

0 Art Mecina over 4 years ago in reply to Wyatt Keller

TI__Genius 16655 points

Thanks Wyatt. However, BQ40Z80 is currently out of stock in the market. He can use BQ34110 but he need balancing and protection & charging solution as well for the same. Is there any available parts which he can use along with BQ34110 for protection, balancing & charging and with stocks?

Also, on the product portfolio for fuel gauges, there are options of Cell Balancing: Internal or External. What does that mean? Can he use those instead if he is okay with 2-4 cells?

Thanks and regards,

Art

0 Wyatt Keller over 4 years ago in reply to Art Mecina

TI__Guru** 105800 points

Hello Art,

Some of the monitors can do protections and balancing, but this would need to be partially controlled by the MCU. I can forward this link to the monitors team if you'd like better suggestions. I would recommend a separate post for a charger recommendation since I specialize with gauges. The BQ25792 charger may be something to consider, but I would need to know more about all the application specifications.

Internal cell balancing uses internal bypass FETs for balancing, in the external balancing you can use external FETs to balance batteries faster.

Sincerely,

Wyatt Keller

0 Art Mecina over 4 years ago in reply to Wyatt Keller

TI__Genius 16655 points

Thanks Wyatt,

Yes, kindly forward to the monitor team for any suitable suggestion that have stocks available.

I created a separate case for the charger as suggested using the BQ25792.

(+) BQ25792: charging solution to go with BQ34110 - Power management forum - Power management - TI E2E support forums

Thanks and regards,

Art

0 Wyatt Keller over 4 years ago in reply to Art Mecina

TI__Guru** 105800 points

Hello Art,

I have forwarded it to the monitor team.

Sincerely,

Wyatt Keller

0 Art Mecina over 4 years ago in reply to Wyatt Keller

TI__Genius 16655 points

Thanks Wyatt!

Best regards,

0 Matt Sunna over 4 years ago in reply to Art Mecina

TI__Guru* 81035 points

Hi Art,

For a monitor with Cell Balancing, I would suggest the BQ76942 or the BQ76930. The BQ76942 is very popular and supply may be limited, but it is the newest and highest-performance monitor. The BQ76930 is also very popular and might be easier to find parts. There is a TI Reference design TIDA-010030 that might be helpful - it uses a monitor with a top-of-stack gauge (BQ76940 with BQ34Z100-G1) so you can use this as a guide for using the BQ34110 with the BQ76930.

Best regards,

Matt