In order to better achieve sustainable development, clean energy (wind, light, electricity) has now become the best choice to replace traditional oil and other fuel energy. In particular, new energy batteries have begun to be widely used in new energy vehicle power batteries and energy storage modules. Tesla pure electric vehicles, including new energy vehicle companies around the world, have taken the lead in transforming from traditional fuel vehicles to new energy vehicles. As a key component of new energy vehicles, the safety of power batteries is particularly important.
Battery management systems are a critical component of electric and hybrid vehicles. In order to ensure the safe and reliable operation of the battery, the battery management system needs to have battery status monitoring and evaluation, charge and discharge control, battery balancing and other functions.
When detecting the cell status (voltage and temperature), we need to use BMS AFE (battery management system analog front-end chip), which is a multi-channel sampling channel monitoring chip that can measure the cell voltage and voltage of series-connected cells. Temperature monitoring. Analog front-end chips generally include a 16-bit ADC, a high-precision voltage reference, a high-voltage multiplexer, and an SPI interface, and are commonly used in electric vehicles, high-voltage mobile equipment, backup battery systems, and high-voltage data acquisition systems.
The following will introduce to you the ADI LTC6813 high-precision lithium battery cell sampling chip.
ADI LTC6813 Characteristics of the sampling chip
Can measure the voltage of up to 12 series cells and supports daisy chain communication
The sampling range is 0V ~ 5V
The total measurement error does not exceed 2.2mV
Use isolated serial communications
Passive equalization can reach up to 200mA, and the chip is configured with PWM control
There are 9 GPIO ports
eLQFP 64-pin package
Withstand voltage is 112.5V
Operating temperature range is –40°C ~ 125°C
ADI LTC6813 sampling chip has up to 18 channels of cell sampling and supports daisy chain twisted pair cascade. Its basic architecture is shown in the figure below:
The ADI LTC6813 sampling chip supports internal and external equalization, but it is generally recommended to use external equalization, which can support larger currents and have better surge suppression. For balancing currents exceeding 200mA, we recommend also using external balancing, because internal balancing can cause overheating, and the balancing resistor selection is usually between 20ohm ~ 60ohm.
The internal equalization structure of the ADI LTC6813 sampling chip is shown in the figure below:
ADI LTC6813 sampling chip external MOS equalization structure, as shown in the figure below:
The ADI LTC6813 chip provides a 4-wire SPI interface that can directly communicate with the MCU microcontroller. It also provides an isoSPI 2-wire interface and requires the LTC6820 bridge chip to convert it to an SPI interface and then connect to the MCU microcontroller.
ADI LTC6813 is widely used in BMS.Please read below for more introduction.
About MAXKGO 18s Slave Board.
MAXKGO 18s Slave BMS Board is a modular BMS based on LTC6813 and STM32 MCU. It is connected to one or more slave boards and integrated integrated boards of different sizes through the ISOSPI interface. The modular BMS can be configured for a variety of applications with battery voltages up to 400V.
LTC6213 18S Slave Features
Aluminum alloy PCB, better heat dissipation effect.
Compatible with MKBMS and ENNOID BMS.
from5-18cells level monitoring per board.
1+8temperature sensorsper slave.
Self-powered by the monitored cells.
Ultra-low power consumption, sleep mode=6uA.
7.It can be connected to multiple slave boards to form an integrated board through the ISOSPI interface
8.1.2mV accuracy, -40 to 120C operation
9.33 ohm balance resistors (0.125A capacity) on all channels
10.Scalable & isolated 1000VDC+
Overcharge protection: Yes
Over discharge protection: Yes
Temperature protection: Yes
Thermal management: Yes
Balance function: Yes
Battery pack capacity detection: Yes
Battery internal resistance detection: Yes
Support battery: support almost all lithium batteries such as lithium ion battery, lithium polymer battery, lithium phosphate battery, etc.
Electric patrol car;
Scenic sightseeing car;
Consumer robots, etc.
In summary, ADI LTC6813 is a high-precision lithium battery cell sampling chip with up to 18 sampling channels. This series supports multi-channel sampling, has the advantages of high precision, excellent hot-swappable performance, and stable communication. Many customers have successfully passed automotive EMC tests using this chip and achieved mass production.
You are welcome to contact us via social media or email:firstname.lastname@example.org，Our MAXKGO team is willing to provide you with more detailed technical answers.
Thank you for your patience in reading, see you in the next blog.