On May 15, the charging head network held an online seminar on 2024 new national standard charger technology for electric bicycles, aiming to explore the impact of many new standards implemented on the electric bicycle charger industry, technological innovation and market trends.
In this seminar, Tino Pan, the representative of Taigao Technology, explained to us how Taigao Technology skillfully integrates gallium nitride devices into the complete solution of lithium battery charger, and discussed how to improve the safety of lithium battery charging through this innovative technology.
Tino Pan has been deeply engaged in the application and development of lithium battery products for more than 20 years, and has in-depth understanding and practical experience in key technologies such as multi cell lithium battery management, battery power metering, and high-power lithium battery charger design.
In the current electric bicycle market, there are two kinds of lead-acid batteries and lithium batteries, of which lithium batteries have become one of the mainstream choices due to their high energy density and long cycle life.These lithium batteries are mainly divided into three categories: square batteries, flexible batteries and cylindrical batteries.It is worth noting that battery pack manufacturers usually divide multiple series of lithium battery packs according to the voltage level of lead-acid batteries.
Specifically, 24V lead-acid batteries correspond to 7-8 series of lithium battery combinations, 36V lead-acid batteries correspond to 10-12 series of lithium battery combinations, 48V lead-acid batteries correspond to 13-16 series of lithium battery combinations, 60V lead-acid batteries correspond to 17-20 series of lithium battery combinations, and 72V lead-acid batteries correspond to 20-24 series of lithium battery combinations.
Under the background of the national standard GB17761 Safety Technical Specification for Electric Bicycles, the specification clearly stipulates that the maximum output voltage of batteries used for electric bicycles shall not exceed 60V.Therefore, as a key product meeting the requirements of the new national standard, the accuracy and safety of the 48V battery charger are particularly important.
Lithium battery management is a quite professional academic field, whose core lies in the fine regulation and analysis of lithium battery, a sensitive component.From the perspective of battery internal resistance and capacity, we will explain it in depth and briefly.First of all, the process of the battery from full charge to full discharge can be viewed from the drawing, with special attention paid to the subtle changes in the battery under different operating temperatures.The experimental data show that when the discharge depth of the battery is about 50%, its internal resistance shows a significant difference.Especially in the temperature range of 0 ℃ and 50 ℃, the difference of battery impedance can be as much as three times.Therefore, the impedance characteristics of battery internal resistance are greatly affected by temperature, charge state and aging degree.
Through experimental analysis, the same lithium battery was tested for 100 charge discharge cycles at the same room temperature.The data on the left shows that with the accumulation of charge and discharge times, the battery capacity shows a downward trend, specifically, the capacity decreases by 3% to 5%.This phenomenon clearly points out that with the increase of use times, the internal resistance of the battery gradually increases, leading to the reduction of battery capacity.In addition, it can be observed from the chart on the right that after 100 charging and discharging cycles, the AC impedance value of the battery almost doubled.This result further confirmed the law that the battery performance degrades with the increase of charging and discharging times.
When designing a multi battery cascade system, it must be recognized that the voltage performance of each battery will be different due to the difference in the internal resistance of the battery.Therefore, in order to ensure the stability and performance of the battery pack, the lithium battery protection board must be integrated with a battery balance mechanism.
Unbalanced battery pack refers to the phenomenon that the voltage of each battery in the battery pack is inconsistent during charging and discharging. The consequences include but are not limited to:
1. The overall operation time of the battery pack is shortened-The charging or discharging process is terminated in advance, affecting the energy utilization efficiency;
2. The cycle life of the battery pack is significantly reduced-The battery is subject to additional pressure because the voltage exceeds or falls below the safety limit.
The function of the battery balance mechanism is to ensure that each battery can reach the full charge state in a similar time by adjusting the voltage difference between batteries, so as to:
1. Maximize the operation time of the battery pack;
2. Avoid damage to batteries with weak performance due to overcharging;
3. Effectively extend the overall service life of the battery pack.
Therefore, battery balance is not only a technical detail in the battery management system, but also a key measure to ensure the performance, safety and life of the battery pack.When designing and implementing the battery management system, we must attach great importance to the introduction and optimization of the battery balance mechanism.
Therefore, in order to ensure the stable operation of the battery pack and extend its service life, the lithium battery protection board with battery balance function must be used.It is known that the imbalance of the battery pack is a common and prone problem.During battery charging, if the charging voltage of a single battery exceeds its rated full charging voltage, the battery life will decline sharply.As shown in the right figure, when the full charge voltage of the battery exceeds its rated value, the life of the battery may be reduced by 50%.
Among many schemes of lithium battery balance mechanism, the starting balance mechanism mainly includes battery SOC comparison method, battery internal resistance comparison method, battery capacity comparison method and battery voltage comparison method.Among them, the battery voltage comparison method has become a widely used method because of its versatility and economy.This method protects the chip by comparing the voltage of adjacent batteries to achieve balance. This process is usually carried out under the condition of low charging current at the constant voltage stage, which means that it needs to go through multiple charging and discharging cycles to achieve battery voltage balance.However, it must be pointed out that the difference between the internal resistance and capacity of the battery cannot be effectively improved through this balance mechanism.
Passive battery voltage balance circuit is widely used in the market.In the charging phase, once the charging current drops below one fifth of the rated value, the circuit built into the protection chip will activate the balance mechanism according to the battery voltage.This mechanism shunts the battery with higher voltage through external resistance to reduce its charging current, so as to achieve voltage balance.To ensure the efficient operation of this mechanism, the BMS system of the battery pack must indicate (through the communication interconnection interface protocol) that the charger should reduce the charging current or use the charging algorithm of the charger itself.
Taigao Technology promotes the following strategic policies:
1. Taigao Technology is committed to elaborately developing a series of high-performance GaN HEMTs. The devices have been optimized to seamlessly replace the traditional Si MOSFETs, thus leading a technological innovation in the electronic field.
2. The product design concept of Taigao Technology emphasizes compatibility and convenience to ensure that GaN HEMTs can be directly connected with the existing PWM controller IC without the need for GaN driver chips, so as to simplify the system integration process and reduce the design difficulty.
3. Taigao Technology focuses on providing customized solutions for electric bicycles, electric motorcycles, electric tools and industrial markets.GaN HEMTs of Taigao Technology is specially designed for the specific needs of these fields, aiming to promote the electrification process of these industries, while ensuring the high efficiency and reliability of products.
Innovation of Taigao's products:
1. Its performance in efficiency, power density, heat dissipation, electrostatic discharge (ESD) protection and integration has reached the excellent level of the industry.It reflects the pursuit of Taigao Technology for technical excellence and the firm practice of its commitment to product quality.
2. Through its unique design and advanced technology, the products of Taigao Technology have greatly shortened the time required by customers in the design and development phase.This not only means that customers can bring their products to the market faster, but also means that they can seize the opportunity in the fierce market competition to achieve higher economic benefits and competitive advantages.
For GaN HEMTs, Taigao Technology has successfully achieved mass production of VDS products with voltage of 650V and resistance range of 120mOhm to 400mOhm.These products are not only technologically advanced, but also highly recognized and praised by customers in the market.
Taigao Technology launched Charger digital chip specially designed for AC/DC charger, which can support the charging algorithm of lithium battery and lead-acid battery. The product integrates high-precision voltage stabilizing circuit, OPA, resistance analog DAC and other circuits, simplifying the design of peripheral circuits.The core function of the chip is divided into two modules: one is to accurately control the charging voltage and current through OPA and DAC to ensure the accuracy and safety of the charging process;Another OPA module is used to amplify the current signal, which improves the resolution of the signal and effectively reduces the power consumption of the system.
In the design of the chip, the CC/CV threshold of the charger is specially optimized to achieve more precise charging control, support the automatic calibration function of the production line, and improve production efficiency and product quality.In addition, we have equipped the chip with simplified GUI software to shorten the R&D cycle and accelerate the speed of product transformation from design to market.
In order to meet the personalized needs of different customers, Taigao Technology provides customized communication bus functions to ensure compatibility and flexibility with various electric bicycle brand systems.At the same time, the design concept of digital chip sub board ensures that there is no need to change the power board, and provides a more convenient upgrade scheme.
The technical innovation of Taigao Technology in the charger industry provides customers with efficient, stable and intelligent charging solutions, and promotes the development of the entire charger industry towards a more intelligent and efficient direction.
The lithium battery charging algorithm of Taigao's digital chip supports MSCC charging. The MSCC, or "Multi Step Constant Current", is a charging strategy for lithium batteries.In this charging method, the charging process is divided into several stages, and each stage uses different charging current and/or voltage to optimize the charging efficiency and battery life.
For lithium battery charging, MSCC has the following help:
1. Improve charging efficiency: By using different currents in different charging stages, MSCC can reduce the current when the battery is close to full charge, reduce the risk of overcharging, and improve the overall charging efficiency.
2. Extended battery life: The life of lithium battery is affected by the number of charging cycles and the temperature during charging.MSCC reduces the stress and temperature rise of the battery during charging by controlling the charging current and voltage, thus extending the service life of the battery.
3. Safety: Lithium batteries may have safety risks when overcharged or charging current is too large.The MSCC charging strategy can avoid these risks because it adjusts the current and voltage in different charging stages to ensure that the battery is within a safe charging range.
4. Battery performance optimization: MSCC charging can intelligently adjust the charging scheme by accurately analyzing the real-time status of the battery, including but not limited to key parameters such as residual power and temperature.The core of this process is to work closely with the Smart Battery technology in the battery management system to ensure that the battery is always in the optimal working state.This refined charging strategy not only extends the service life of the battery, but also improves its performance, reflecting the ultimate pursuit of battery health management.
In a word, MSCC charging strategy, through its multi-stage charging method, can improve charging efficiency, extend battery life, enhance safety, and optimize battery performance. It is an advanced lithium battery charging technology.
In addition, for the charging protection mechanism, the ADC accuracy error of voltage and current is less than 5% to optimize the charging efficiency and charging safety.
At the same time, in order to meet the diversified needs of customers, Taigao's digital chips integrate customized communication bus solutions.It ensures that the product can be compatible with and flexibly adapt to various system architectures.At present, the chip has successfully integrated 1-Wire, URAT, RS-485, encryption authentication and other communication protocols.Looking forward to the future, Taigao Technology promises to continuously expand its technical boundaries and plans to introduce communication protocols such as CAN Bus, UFCS, PPS, etc. to further enhance the functionality and market competitiveness of its products.
Taigao Technology is committed to the in-depth development of the field of lithium battery chargers, and provides comprehensive product upgrading solutions for the product transformation needs of PD chargers and power adapter customers.
These solutions are the results of our team's research and development, aiming to provide you with one-stop, efficient and convenient charging solutions.We know that time is money and efficiency is competitiveness in a fast developing market.
We look forward to working with you who are interested in our program and looking for cooperation.Whether you are seeking technical cooperation, product customization, or market expansion, our complete set of solutions can meet your needs, help you quickly enter the market and seize the opportunity.
Please contact the business of Taigao Technology immediately, and we will respond quickly to establish contact with you to explore the possibility of cooperation.
Contact: Mr. Zhang
Contact: 18088882102
Contact: Mr. Pan
Contact: 13691750205
Summary of charging head network
With the innovation and breakthrough of Taigao Technology in the field of GaN devices, the safety, efficiency and intelligent level of lithium battery chargers have been significantly improved.Taigao Technology has thoroughly discussed the full range of solutions for lithium battery chargers, from battery classification, voltage level, safety specifications, to battery management, balance mechanism, to various technologies of chargers, which comprehensively demonstrates how Taigao Technology can meet the needs of the market and users through technological innovation.
The GaN HEMTs device of Taigao Technology leads the technological innovation in the electronic field with its high efficiency, high power density, excellent heat dissipation performance and electrostatic discharge protection.The seamless connection with the existing PWM controller IC simplifies the system integration process, reduces the design difficulty, and provides customized solutions for electric bicycles, electric motorcycles, electric tools and industrial markets.
The digital chip of Taigao technology integrates high-precision voltage stabilizing circuit, OPA, resistance analog DAC and other circuits, simplifies the peripheral circuit design, optimizes the CC/CV threshold of the charger, and realizes more precise charging control.At the same time, the customized communication bus function provided ensures the compatibility and flexibility of the product with various electric bicycle brand systems.The introduction of MSCC charging strategy further improves the charging efficiency, prolongs the battery life, enhances the safety, and optimizes the battery performance.The ADC accuracy error of voltage and current is less than 5%, which optimizes the charging efficiency and charging safety.
Taigao Technology will also continue to explore the lithium battery charger market, meet the transformation needs of PD and adapter customers, continue to expand the technology boundary, and enhance the functionality and market competitiveness of products.
Taigao Technology Co., Ltd. is unswervingly committed to developing and providing excellent charging solutions, which are not only efficient and stable, but also integrated with intelligent technology.Our goal is to lead the charger industry to a new era of intelligence and efficiency, so as to ensure that users can enjoy unprecedented safe, convenient and environmentally friendly charging services.We firmly believe that through our unremitting efforts and innovation, we can create a greener and more efficient energy environment for users.