I have previously written a disassembly series of the blade battery system.
Recently, after some twists and turns, I managed to obtain the board of the blade battery with the help of a friend. It is quite interesting to actually see these boards, so I would like to share with you. The updated information is as follows:
There are a total of 11 CMUs, divided into two types. The AFE chip adopts Maxim’s MAX17853, with 14 channels for acquisition, and the isolating device used is C:P0612.
The balancing resistor selected is a 20-ohm wide edge resistor. The label “20 ohms” actually refers to the total number of 14 wide edge resistors.
The interface of the Shunt and the control of the 3 relays are integrated together.
The BMU’s control chip uses the SAK-TC234L from the AURIX™ TC23xL series.
I have marked the main chips on the figure for your reference.
The diagram below is the block diagram of the main components of the current generation BMU. Compared with the previous generation design, the main change is the transition from DCDC+LDO to SBC chip, and the integration of one-way CAN. The MCU has been changed from MC9S12XET256MAL to SAK-TC234L. I estimate that the algorithm for lithium iron phosphate still has some differences in computing power requirements, and it has been changed from EEROM to 8MB flash, so some calibration data may be affected.
Note: The previous generation power chips mainly include TPS54260, LT3471, and TPS39801.
The difference between the two generations lies in the circuit design of the low-side switch (74HC595D). This time, HSD+LSD was used, and a large amount of analog input and status detection were eliminated. The interface of the Shunt and the UART communication interface of the AFE are integrated.
Note: The previous generation had a Daisy Chain communication conversion module to convert to CAN.
This article is a translation by ChatGPT of a Chinese report from 42HOW. If you have any questions about it, please email bd@42how.com.