Main content:
BMS IC, which acts as a battery nanny in the battery operation system. The signals processed by BMS IC are rich enough, including: battery, collision, CAN, charging, water pump, high voltage, insulation and so on. A single overdischarge can cause permanent damage to the battery. In extreme cases, the lithium ion battery overcharge or overheat, which can lead to thermal runaway, battery rupture or even explosion.
Therefore, the BMS IC can accurately measure the usage status of the battery pack, protect the battery from overcharging and discharging, and balance the power of each battery in the battery pack. And analyze and calculate the power of the battery pack and convert it into understandable endurance information to ensure the safe operation of the power battery.
1. What are the main chips in BMS IC?
● AFE module: realize battery information collection, status monitoring and other functions
AFE (Analog Front End Front End) is an integrated component containing sensor interface, Analog signal conditioning circuit, Analog multiplex switch, samplehold, ADC, data cache and control logic and other components of the memory and control logic components. Some AFEs also come with MCU, DAC and multiple driver circuits and multiple driver circuits.
● Battery balance module: Improves battery life and cycle life
Unbalanced batteries can affect battery life and battery cycle life. Unbalanced battery is manifested in that the voltages of each battery are not equal when multiple batteries are connected in series, especially at the end of charging and the end of discharging. The equalization circuit mainly includes active equalization and passive equalization. Active balancing is to transfer the extra power from the cell with the most power to the cell with the least power, or to the entire string of batteries to achieve energy recovery. Passive balancing is to consume the extra power from the cell with the most power through resistance heating.
● Calculation unit: realize control, calculation and other functions
As a computing platform, MCU needs to meet AEC-Q100, ISO26262 and other certifications. Taking ADI 48V hybrid BMS IC as an example, MCU plays the functions of relay control, SOC/SOH estimation, equalization control, cell voltage, current, temperature data collection, data storage, etc. Compared with consumer-grade and industrial-grade MCUs, automotive-grade MCUs have higher industry barriers.
● Isolation circuit: realize electrical isolation between high and low voltage modules
Isolation devices realize electrical isolation between high and low voltage modules, and the technical route includes optocoupler isolation and digital isolation. The isolation device is a safety device that can convert and output the input signal to achieve electrical isolation between the input and output ends. Electrical isolation can ensure the safety of signal transmission between the strong current circuit and the weak current circuit. If there is no electrical isolation, once a fault occurs, the current of the strong current circuit will flow directly to the weak current circuit, causing damage to the circuit and equipment. In addition, the electrical isolation removes the ground loop between the two circuits, which can block the propagation of interference signals such as common mode and surge, so that the electronic system has higher safety and reliability.
2. Major BMS IC chip manufacturers in Europe and America
In BMS IC chips, there are not many AFEs to choose from. The internal structure of the AFE that can be accessed is similar, the difference lies in the number of sampling channels, the number, type and architecture of the internal ADC. The main suppliers of AFE are ADI, TI, ST, Panasonic, NXP and Renesas. Among them, ADI's product lines mainly come from acquired Linear and Maxim, and Renesas' products mainly come from acquired Intersil. The suppliers of AFE products are mainly foreign companies. From the perspective of MCU, the main suppliers are TI, ST, NXP, Infineon, Renesas and so on.
At present, many MCU manufacturers in China are actively deploying automotive-grade products, such as GigaDevice, Chipsea, Ninestar, Espressif, Beken, and so on. In terms of ADC, the main suppliers are TI, ADI, ST, Renesas, etc., most of which are American manufacturers. China mainly includes Shanghai Belling, 3peak, SG Micro, and Chipsea. In terms of digital isolation, it is mainly used for digital communication between high and low voltages, such as the SPI communication between the high-voltage sampling on the BMS IC main control board and the MCU, and the SPI communication between the sampling board AFE and the MCU. The main suppliers are ADI, TI, Silicon Labs, etc. Of course, in addition to using digital isolators, optocouplers, or transformer isolation schemes can also be used.
3. Representative BMS IC chips
The electrification of automobiles is developing rapidly and irreversibly, and BMS ICs have become the primary core issue. TI has made great achievements in the field of BMS IC for electric vehicles, and has successively released wired BMS IC and wireless BMS IC solutions that meet the ASIL D standard, leading the industry. ST has led the semiconductor market for many years, and its chip applications span many fields, and it has also become a major supplier of automotive chips. In the automotive field, in order to meet the market and design needs, the L9963E battery monitoring and protection chip was launched, aiming to solve the design problems of battery management systems faced by electric vehicles all over the world, including China.
ADI launched the first integrated high voltage battery stack monitor in 2008, and it has been iteratively updated to the fourth generation, and the fifth generation product is still in the research and development stage. The LTC6811-1 is ADI's fourth generation BMS IC, a battery pack monitor. Up to 12 batteries in series can be tested for voltage, the measurement accuracy is higher than that of ST L9963, the total measurement error is less than 1.2mV, and it only takes 290μs to complete the detection of 12 batteries.
Infineon's BMS ICs include the TLE9012DQU and TLE9015DQU models, which provide optimized solutions for battery monitoring and equalization. The new BMS IC can achieve higher measurement accuracy and excellent application robustness, providing system solutions for battery topologies of battery modules, module-less battery technology and battery-chassis integration technology. It enables automotive BMS IC solutions to meet the requirements of ASIL-D, the highest level of automotive functional safety, and comply with the ISO26262 standard.
4. How about Chinese BMS IC chips?
At present, the scale of China's BMS IC chip market is billions of pieces per year, of which only 20% of the market is from Chinese brands, and very few of them can be used in electric vehicles. Most of them are monopolized by foreign manufacturers, and Chinese BMS IC companies only carry out secondary development on this basis, including hardware design and software construction. However, Chinese semiconductor companies have already made arrangements in the field of BMS IC chips.
Affected by the new crown, the growth rate of the global BMS IC market in 2020 will decline, but the Chinese BMS IC market still occupies an important position. In the future, with the expansion of the electric vehicle market and the improvement of battery efficiency requirements, the BMS IC market size is expected to achieve stable growth. According to relevant data, the global BMS IC market size is expected to be US$6.512 billion in 2021, and is expected to reach US$13.1 billion by 2026, with a CAGR of 15%. It is predicted that the global BMS IC chip market size is expected to reach 9.3 billion US dollars in 2024, and the market space is broad.
5. Where do the used batteries from electric vehicles go?
The sales of electric vehicles in China began to increase in 2015. With the continuous growth of the number of electric vehicles, as of the end of March 2022, the number of electric vehicles in China reached 8.915 million, accounting for 2.90% of the total number of vehicles. Although BMS IC chips are constantly being upgraded, which can better optimize battery performance and prolong battery life, a new battery must be replaced once the capacity of the power battery decays to 80%. With the development of electric vehicles in recent years, the number of retired power batteries has been increasing year by year. Our website has previously compiled the top 10 power battery companies, this article can help you understand the development of power battery companies in more detail.
How to deal with retired batteries has become an imminent development problem for the electric vehicle industry. According to statistics, the current recycling rate of power batteries in China is only about 10%. Therefore, the need for recycling waste power batteries is becoming more and more urgent. The Chinese government has promulgated relevant policies to encourage cascade utilization enterprises to cooperate with enterprises in electric vehicle production, power battery production, and recycling and dismantling of end-of-life vehicles, strengthen information sharing, and utilize existing recycling channels to efficiently recycle waste power batteries for secondary use.
Encourage power battery manufacturers to participate in the recycling and cascade utilization of waste power batteries. Europe, the United States, Japan and other countries developed electric vehicles earlier, and have established relatively complete power battery recycling systems. At the same time, more and more car companies and equipment companies have begun to use retired batteries as energy storage devices to provide support for energy storage systems.
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