Disassembly of the EV05 BMU-60S battery management system

qinyunti

Disassembly of the EV05 BMU-60S battery management system [Copy link]

Preface

Participate in EEWorld's new teardown event

https://en.eeworld.com/bbs/thread-1282959-1-1.html

This article shares the disassembly of the Yineng battery management system EV05 BMU-60S

EV05S Platform Introduction

The EV05S platform product adopts a master-slave architecture. The main board (BCU) and the slave board (BMU) communicate through CAN. It is compatible with 12V and 24V power supplies. The BMU has a variety of voltage channel configurations. It is a product with rich interfaces, flexible adaptation, high cost performance and reliability. It is suitable for application scenarios such as electric buses, heavy trucks, and logistics vehicles.

The one disassembled here is from board 60S.

The main hardware functions are as follows

BCU		BMU ( 60S/48S/36S/24S )
Support KL15, A+, RTC, CAN, CC, CP wake-up		60/48/36/24-channel single-cell voltage detection
2-way total voltage detection	Insulation testing	External balancing method	25Ω balancing resistor
4-way high-side relay driver	2-way low-side relay driver	10-channel temperature detection	1-way CAN communication
5V power output	Shunt Current Sensing	2-way high-side relay driver	1 channel DI
Electromagnetic lock control	National standard charging interface detection	BCU size (L*W*H)	220*115*30
3-way CAN communication	2-way DO	BMU-60S Dimensions (L*W*H)	310*100*26
4-way DI	2-way AI	BMU-48S Dimensions (L*W*H)	272*100*26
5-way temperature detection	Real Time Clock	BMU-36S Dimensions (L*W*H)	228*100*26

Scope of application

Application Terminal	Passenger cars, logistics vehicles, light trucks
Battery Type	LFP, LTO, NCM	IP Rating	IP40
Supply voltage	6-32V	Maximum number of battery strings	400 strings
Maximum total voltage	1000V	Current sensor type	Shunt, Hall

Exterior

On the front, there is model information, E-Pow Electronic Battery Management System EV05 BMU-60S

You can refer to the official website http://www.hzepower.com /

Obtained ISO/TS16949 automotive industry quality management system standard

Board Information

The certificate shows that it is a 16-year-old product.

On the back, there are mounting holes all around.

Connectors

Disassembly

Remove the 6 screws around

I opened the cover and saw that the PCB was still quite new.

Because the outside was too dirty, I simply rinsed it before, and paid special attention to the flushing direction, just a small stream of water.

After disassembling it, water still seeped in, so the structure is basically not waterproof. The upper and lower covers are buckled, there is no rubber gasket, and there is no bayonet structure. The appearance also specifically reminds you to pay attention to waterproofing, and it can be seen that the design is not waterproof.

You can see the PCB board, the whole board is made of three protections

The software and hardware version information can be seen from the PCB. The PCB was designed in 2014, which is 10 years ago.

The pcb manufacturing factory is Aoshikang Technology Co., Ltd. - askpcb

Look at the plug-in details Y158261 Y162057, they are all standard connectors commonly used in automobiles.

The heat dissipating silicone is only attached to the panel, and the silicone bonding part is in direct contact with the panel. There is a layer around it, and I don't know if it has the function of heat insulation, that is, it prevents heat from being conducted to the side. There are large electrolyte capacitors nearby, etc., so that the heat is only dissipated from the silicone contact surface.

Remove the silicone and see the sub-board

Continue to unscrew the 7 screws around the PCB board. You will see that the screws, labels and other positions are marked with inspection marks. Generally, large manufacturers will have a quality assurance system and will be more standardized.

I saw that the ground was also covered with a layer of

A close-up of the front and back of the PCB

The board is divided into several areas

Control section

The battery management part, balancing and other functions are actually 5 identical parts.

It can be seen that the small board is directly soldered with pin headers instead of using pin and mother headers. The advantage is that it is fixed reliably, but it does require tooling for positioning during welding, and it is not easy to maintain and it is difficult to see the details inside.

5 groups, 14 channels per group, 500mA fuse

Let’s take a look at the main components

5CAV8GT

ISO7241C 4-Channel Digital Isolator

NXP's JTA1051 is a high-speed CAN transceiver chip. NXP has a high market share in the automotive electronics field. The automotive industry generally uses CAN communication.

MCU is still NXP's S9S12G64

16-bit MCU, S12 core, 64KB Flash, 25MHz, -40/+105degC, Automotive Qualified, QFP 64.

Performance resources are average, mainly automotive grade.

8M crystal

Silk screen AEQC

Next to it is ATML's EEPROM

ATML

6400

TDK

ZJY51O1 Common Mode Choke/Filter

836GEV50

Summarize

1. The structural design does not take waterproofing into consideration, there are no rubber gaskets or buckles.
2. It can be seen that the automotive industry components are still dominated by international manufacturers, such as NXP, etc. I hope that domestic automotive-grade ICs can rise.
3. The whole board has triple protection and good thermal design.
4. The performance requirements of the corresponding control part are actually not high. A 16-bit 25MHz MCU, 4KRAM, and 64KBFLASH MCU can do the job.

Jacktang

The whole board has three protections and good thermal design. This is quite impressive.

The structural design does not take waterproofing into consideration, there are no rubber gaskets or buckles, are there any potential problems?

okhxyyo

Your speed!!!

lugl4313820

When I first saw the description of the interface, I found that this design is quite user-friendly. The original poster took so many pictures while disassembling this, which must be very hard. Regarding the use of NXP products, it may be in high-end games. Domestic chips really need to work harder.

lansebuluo

What is the 25Ω balancing resistor used for?

qinyunti

lansebuluo posted on 2024-6-12 08:49 What is the indicator of 25Ω balancing resistor used for here

The so-called balancing is a string of batteries connected in series, some with high voltage and some with low voltage. The purpose is to make their voltages consistent so that their lifespans are basically the same.

As the batteries are used, the voltages of the batteries will inevitably be different. In this case, the batteries with higher voltages should be charged less and discharged more, and vice versa for the batteries with lower voltages. The principle is to connect a path in parallel at both ends of the battery. For batteries with higher voltages, open this path, and the parallel shunt will be used. The charging current of this battery will be smaller than that of other batteries in series, which will play a balancing role. For example, the resistance of this parallel path is 25 ohms, and the battery is 3.7V. The shunt (i.e. balancing) capacity of this parallel path is 3.7V/25 ohms. The smaller the resistance, the greater the balancing capacity. There are certain algorithms for balancing. Generally, only one battery is balanced at a time. Generally, the battery with the maximum voltage is found to align and balance. Both charging and discharging can be balanced. Of course, there are also some other judgment condition logics for start-stop balancing.

hjh0512

There are so many pictures. The poster put a lot of effort into it. I’ve saved them and will look at them later when I can understand them.

wangerxian

I feel that power supply is a major difficulty and essence of a product, and determines the stability of a product.

lansebuluo

qinyunti posted on 2024-6-12 10:17 The so-called balancing is a series of batteries, some with high voltage and some with low voltage, the purpose is to make their voltage consistent so that their lifespan is basically the same. ...

I can roughly understand the effect. Isn't this a waste of energy? I feel that the balancing algorithm you mentioned has a lot of load in it.

se7ens

lansebuluo posted on 2024-6-13 08:45 I can roughly understand the effect. Isn't this a cost of consuming electricity? I feel that the balancing algorithm you mentioned has a lot of load in it

This is a passive balancing method, which consumes excess energy by generating heat. A more efficient method is the active balancing method, which achieves uniform charging and discharging currents by connecting capacitors in parallel.