BQ40Z50: BMS IC

Diwakar Bogoju

Part Number: BQ40Z50
Other Parts Discussed in Thread: , BQSTUDIO, EV2400, GPCCHEM, BQ34Z100

Hi TI experts ,

I'm designing a BMS for 3 cells in series, where entire pack is 11.1V and 2500mAH.

I should achieve over voltage protection(12.6v), under voltage protection(9v), over current protection and short circuit protection.

And My charge current should be less than 4A and Discharge current should be less than 8A.

can you please suggest me IC for this requirement and its evaluation Board.

And Do TI BMS chips support parallel connections as well like (3S2P)?

Regards,

Diwakar.B

over 3 years ago

0 Shirish over 3 years ago

TI__Guru 57697 points

Hello Diwakar,

The bq40z50 is a good choice. The EVM information is at https://www.ti.com/tool/BQ40Z50EVM-561.

All the BMS chips support parallel cell connections.

0 Diwakar Bogoju over 3 years ago in reply to Shirish

Prodigy 20 points

Hello Shirish,

Thanks for the reply,

If I buy this Evaluation Board BQ40Z50EVM-561, Will this kit come with programmer or I have to buy the programmer separately.

And If I can Connect the batteries in parallel to this board BQ40Z50EVM-561.

Please share me the connection diagram for 3S2P Battery connection.

Can we configure the BMS with Programmer, Like can I set the Under voltage, Over Voltage and Charge Current of BMS with Programmer.

0 Shirish over 3 years ago in reply to Diwakar Bogoju

TI__Guru 57697 points

Hello Diwakar,

Refer this document for all design information

https://www.ti.com/lit/an/slua660a/slua660a.pdf

You will put 2 parallel cells between 1N and 1P. Repeat the same between 1P and 2P. Again between 2P and 3P.

You will need an EV2400 with the BQ40Z50EVM-561 and download BQSTUDIO to program and create a golden image that can be used for production

0 Diwakar Bogoju over 3 years ago in reply to Shirish

Prodigy 20 points

Hello Shirish,

Thanks for the reply,

Can you briefly explain how to set the BMS settings with Programmer

Under voltage - 10V

Over Voltage - 12.6V

Charge Current - 2.5A

Discharge Current - 6A

Please help me on this configurations.

0 Shirish over 3 years ago in reply to Diwakar Bogoju

TI__Guru 57697 points

Hello Diwakar,

There are more settings that just the threshold because you want to exclude transients that are a result of normal system operation.

Check the "Protections" subclass of Data memory. Refer the TRM for details of each parameter.

0 Diwakar Bogoju over 3 years ago in reply to Shirish

Prodigy 20 points

Dear Shirish,

Could you please provide us a demo on how to configure the below mentioned specification.

Under voltage - 10V

Over Voltage - 12.6V

Charge Current - 2.5A

Discharge Current - 6A

0 Wyatt Keller over 3 years ago in reply to Diwakar Bogoju

TI__Guru** 107685 points

Hello Diwakar,

To set the protection thresholds you can just input the changes in the data flash section and hit enter, it will write them to the gauge.

Usually we care more about cell under voltage (CUV) and cell over voltage (COV) for applications, so you can just program in the CUV and COV thresholds by dividing your thresholds by the cell count. Charge current protections and discharge current protections are also configurable in the data memory.

You can find more helpful documents and guides on the BQ40Z50 FAQ page: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1106884/faq-bq40z50-faqs

Sincerely,

Wyatt Keller

0 Diwakar Bogoju over 3 years ago in reply to Wyatt Keller

Prodigy 20 points

Hello Ti Experts,

We are planning to use these Li-ion cell batteries

Part Number: BAK H18650CQ

Link: https://www.rytronics.in/product/bak-h18650cq-2550mah-3-7v-3c-li-ion-rechargeable-battery/

Can I use BQ40Z50EVM-561 Board as BMS for these Cells.

And one more thing, Can I use EV2300 also for Programming BQ40Z50EVM-561 board.

0 Shirish over 3 years ago in reply to Diwakar Bogoju

TI__Guru 57697 points

Hello Diwakar,

Use the GPCCHEM tool to find if there is a good chemistry match for these cells. If there is a good match then you can use it with bq40z50EVM-561.

You can use the EV2300 and bqStudio for programming (assuming the EV2300 is recognized by Windows). We recommend using an EV2400 if you don't already have an EV2300, because the EV2300 may not always be recognized on 64 bit Windows.

0 Diwakar Bogoju over 3 years ago in reply to Shirish

Prodigy 20 points

Hello Ti Experts,

My Board will work on main power and when main power is not available(OFF), it automatically switches to Battery Power.

When Main power is available it will charge the battery, when main power is OFF battery will discharge

And the charge and Discharge happens at same pins (BAT+ & BAT-).

So, I have to connect this BAT+ & BAT- to PACK+ and PACK- in Evaluation Board BQ40Z50EVM-561?

Will that work for both Charge and Discharge.

0 Wyatt Keller over 3 years ago in reply to Diwakar Bogoju

TI__Guru** 107685 points

Hello Diwakar,

When you say the battery pins (BAT+ and BAT-) the charge and discharge should be occurring through the PACK+ and PACK- of the gauge EVM. for multicell configurations the gauge needs to read the voltage of each cell on the battery side. If you bypass the PACK connections you will not have any gauge protection and the gauge will not be able to sense the current flow.

Sincerely,

Wyatt Keller

0 Diwakar Bogoju over 3 years ago in reply to Wyatt Keller

Prodigy 20 points

Hello Keller,

Actually the BAT+ and BAT- are the notations in my board.

Where the charge and discharge should happen.

I am using this evaluation board, please check the below link

https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/dc1830b-c.html#eb-overview

So, If I connect my connections at Pack+ and Pack-, will the charge, discharge and reading the voltage on each cell happens

0 Wyatt Keller over 3 years ago in reply to Diwakar Bogoju

TI__Guru** 107685 points

Hello Diwakar,

I'm not familiar with the EVMs from Analog Devices, but you will need all the cell voltage connections to the BQ40Z50, it is not a top of stack gauge like the BQ34Z100. You can use the our BQ40Z50 EVM as a reference for your connections, the user guide explains all the connections needed.

https://www.ti.com/lit/pdf/sluuav7

Sincerely,

Wyatt Keller

0 Diwakar Bogoju over 3 years ago in reply to Wyatt Keller

Prodigy 20 points

Hello Keller,

The EVM I have shared from Analog Devices is a Powerpath controller, which I am already using for switching between Main power and Battery power.

I want to use BQ40Z50 board as a BMS for Batteries.

So the power path controller has two pins Bat+ and Bat-, If i connect those pins to Pack+ and Pack- the charge and discharge happens right.

Please confirm on this

0 Wyatt Keller over 3 years ago in reply to Diwakar Bogoju

TI__Guru** 107685 points

Hello Diwakar,

The PACK+ and PACK- connections on the EVM should be used to interface with your system for charge and discharge.

Sincerely,

Wyatt Keller

0 Diwakar Bogoju over 3 years ago in reply to Wyatt Keller

Prodigy 20 points

Hello TI Experts,

Thanks for your reply,

Can this BMS cutoff the Discharging of Battery when the current in it is 1A.

Can I set this parameter in this Evaluation Board BQ40Z50EVM-561?

I mean can I set the discharge current range as well

Please suggest.

0 Shirish over 3 years ago in reply to Diwakar Bogoju

TI__Guru 57697 points

Hello Diwakar,

You can setup the Protections to trigger to set your operation range. Check the Protection settings in "Data memory". The protection features control charge and discharge FETs.

Power management

Power management forum

BQ40Z50: BMS IC