More and more wireless and battery-powered devices are infiltrating into daily life, including applications such as electric vehicles (EVs) and solar energy storage systems (ESS). How to manage batteries efficiently will be an important issue. This article will show you the battery management system (BMS), battery formation, GaN FET, lithium carbon capacitor (LCC), energy storage module system, and other solutions to further comprehensively understand the related technologies of battery applications.
At present, the trends for the rapid development of EVs and ESSs are further promoting a steady increase in the demand for producing batteries with different charging capacities. In particular, battery formation plays a very important role in various applications that use batteries to store energy.
Complete battery formation power supply system solutions
With the increasing demand for batteries in the market, battery manufacturers find themselves facing the challenge of improving efficiency and meeting the required volume during the whole production process. The basic stage that each battery needs to go through in the manufacturing process is battery formation. In particular, the newly assembled battery is first charged and discharged with high voltage and current accuracy in order to activate the battery material. The formation cycle has a great influence on battery life, quality, and cost, but it is a bottleneck in the current production process because of its high cost and long time consumption.
Infineon optimizes its product portfolio with its comprehensive cost and efficiency, and provides a full spectrum of power system solutions to fully meet the application requirements of high accuracy, high efficiency, and power density. Infineon's solutions can provide high voltage and current accuracy (up to 0.01%) during the charging and discharging cycles, with high power density and high efficiency, and can provide the optimal thermal management during operation, as well as 24/7 operation cycles for high system reliability.
Infineon's main products in battery formation applications include OptiMOS™ and StrongIRFET™ low-voltage power MOSFETs, and CoolMOS™ high-voltage power MOSFETs, as well as EiceDRIVER™ gate driver ICs, TRENCHSTOP™ discrete IGBTs, and XMC™ microcontrollers. These products are efficient, innovative, and cost-attractive solutions, which can save on overall BOM, reduce the size of high-power density semiconductors, and have a complete ecosystem to speed up the time to market, including simulations, documents, and demonstration boards. Infineon's quality improves the service life and reliability of the products and provides a one-stop-shop service portfolio.
Provides a highly integrated solution for automotive battery management applications
In order to meet the needs of automotive and energy storage battery management applications, Arrow Electronics launched the BMS reference design for electric vehicle and energy storage applications. BMS is an electronic control circuit that monitors and regulates battery charging and discharging. The reference design consists of Infineon's powerful automotive grade Traveo II MCU CYT2B97, AFE TLE9012D, and transceiver TLE9015D. TLE9012DQU fulfills four functions: cell voltage measurement, temperature measurement, cell balancing, and isolated communication, while TLE9015D is used as a transceiver to connect TLE9012DQU and MCU main battery controller. In addition, the solution integrates pressure detection, RTC, and system voltage and current sensing functions.
This BMS reference design has the advantages of reducing costs, optimizing size, reducing software effort, and shortening time-to-market. It can balance and monitor up to 12 battery cells connected in series. It has a 12-channel dedicated 16-bit delta-sigma ADC battery voltage monitor with an accuracy of about 5.8 mV. 7μS fast and synced cell voltage sampling with 2Mbit/s iso-UART is used. It has an internal current balance of up to 200mA and 5-channel temperature sensors. Pressure sensors and external RTCs can be reserved to support system voltage and current sensing.
Complete feature of current conversion solution
In the market, AC sources are either three-phases or single phase. In terms of the three-phase AC input of the power stage, Arrow Electronics cooperates with ST to develop a bidirectional AC-DC converter solution, which can be used for 15kW battery formation or energy storage applications. This reference design provides a complete three-phase AC/DC and DC/AC (800 VDC to 400 VAC) power conversion solution based on a digital platform. It is well suited for the Active Front End (AFE) stage in high-power charging stations, industrial battery chargers and UPS. The high switching frequency of the SiC MOSFETs and the multilevel structure allow nearly 99% efficiency as well as the optimization of passive power components in terms of size and cost.
There is a three-phase three-level bidirectional AC/DC converter that supports a rated nominal DC voltage of 800 VDC and a rated nominal AC voltage of 400 VAC @ 50 Hz, with a nominal power up to 15 kW. In the AC-to-DC rectifier mode, the power factor (PF) control is greater than 0.99, with inrush current control and soft startup. In the DC-to-AC inverter mode, it can support active and reactive power control and has an integrated grid connection solution. This reference design uses power sections based on SiC MOSFETs that operate at high frequency (70 kHz) and has a high efficiency greater than 98%, reducing the weight and size of the passive element.
Based on the STM32G474 microcontroller family, the control section P2P is compatible with different power converters solutions, with 4 integrated high-performance op-amps, and SWIM, UART, I²C, DACs control and monitoring interfaces, supporting 64-pin digital power connector, overcurrent, and overvoltage protection.
For single-phase AC input applications in the power stage, Arrow Electronics and ST provide bidirectional AC-DC converter solutions focus on 6.6kW battery formation and energy storage applications. This 6.6kW bidirectional energy storage system can support AC/DC bidirectional power conversion, with a maximum charging power of 6.6kW, an AC input voltage range of 180-265 VAC, a DC output power of 60-90VDC, and a maximum inversion power of 6.6kW. The rated input for inversion is 80VDC, and the rated output is 220VAC 50Hz. The efficiency of this system is greater than 95%, and it supports Totem Pole PFC at 100 kHz and CLLLC 200kHz. This solution can also be applied to solar inverters with energy storage, forklift chargers, AC and DC loading equipment, and other similar applications.
In addition, Arrow Electronics and ST have also launched a 6.6kW bidirectional CLLC power converter that supports a dual symmetric CLLC DCDC converter and can achieve a maximum bidirectional power conversion of 6.6kW. The efficiency of this converter is expected to exceed 98%. The input voltage is 550VDC, and the output voltage is 60-90VDC. The rated input for inversion is 80VDC, and the rated output is 550VDC. The PCB size of this converter is 450mm x 330mm x 100mm (LxWxH). Above solutions are based on STM32G474 microcontroller family and latest ST analog and power devices.
Design scheme and core advantages of GaN on battery applications
Lithium compound batteries have battery protection requirements, and the battery protection chip will detect various abnormal conditions of the battery, including overvoltage, undervoltage, discharge overcurrent, short circuit, and so on. EPC's GaN is based on the unique inherent characteristics of its GaN FET (there is no parasitic diode between the drain and the source), which realizes a bidirectional voltage turn-off function in a die. GaN has the advantage of being one for two. In high current applications, the system cost advantage is obvious, and its package is small, which can effectively reduce the PCB size, facilitate the layout of high-density PCBs, and provide low internal resistance, which can effectively reduce the system conduction loss and improve the overall endurance of the system.
Compared with the silicon MOS scheme, topologically requires two back-to-back common drains for a silicon MOSFET (100V 2.7mΩ), and the package is SO8 (6.15 x 5.15 mm), Vds is 100V, Vgs_max is +10V, Ron_max is 2.7×2=5.4mΩ, and Id is 194A, so 16 silicon MOS is required. However, EPC's GaN scheme (EPC2302 (100V 1.8mΩ) only needs one GaN, and the package adopts the QFN 3x5mm, Vds is 100V, Vgs_max is +5V, Ron_max is 1.8mΩ, and Id is 408A, so only six pieces are required, which has the advantages of a smaller package and lower system cost.
GaN devices are also being widely used in solar power applications at present because they have obvious advantages in efficiency, size, weight, and long lifetime. Solar power applications need to ensure a service life of more than 20 years, and have excellent thermal performance and high power density to increase the power of the same form factor or integrate with the panel. The trend toward higher power density makes the cooling system very expensive, and state-of-the-art silicon MOSFET solutions can no longer meet the required power density. Therefore, leading solar companies are adopting GaN.
A GaN FET is very small and the switching loss is very low. This enables higher switching frequency to increase power density, while still providing higher efficiency than silicon MOSFET solutions to meet thermal challenges and save cooling costs. The excellent reliability of GaN can support a service life of 25 years.
EPC's 100V, 150V, 170V, and 200V GaN devices are very suitable for the primary stage of micro inverter or separate MPPT/optimizer. EPC 200V and 350V devices can also be used in multi-level topologies of Battery Energy Storage Systems (BESS) or string inverters.
GaN FET can also be used in solar panel optimizers, which can optimize the power of each solar panel. In micro inverter applications, GaN can provide higher power density, excellent thermal performance including easier cooling or increased power, excellent reliability, and proven service life. In addition, GaN FETs can also be used in 200V and 350V multi-level topological ESSs, allowing the use of smaller voltage devices with smaller form factors, reducing dV/dt, and increasing the equivalent output frequency, thus improving efficiency and density, simplifying cooling, and limiting stress in components to prolong service life.
GaN's industrial applications include 60~150V ESSs, < 60V ESSs, EVs/HEVs, electric bicycles, power tools, drones, sweepers, smartphones, tablets, notebooks, etc.
Lithium-carbon capacitors have superior characteristics to traditional batteries
An LCC (Lithium Carbon Capacitor) is an asymmetric supercapacitor. The negative electrode material is the same as the supercapacitor. The positive electrode is modified to greatly improve the energy density, which is 15-20 times that of a traditional supercapacitor. Through ion adsorption combined with shallow intercalation and desorption of lithium ions, high energy density is realized, which has the characteristics of high-rate charge and discharge, high safety, long service life, and being maintenance-free. Because the safety of traditional batteries is uneven, both lead-acid batteries and lithium batteries have safety problems, and lithium batteries may explode when they are short-circuited, while LCCs have high safety performance, so there will be no explosion or fire when they are directly short-circuited.
Traditional batteries are generally nickel-chromium/lead-acid batteries and lithium batteries. In terms of charging efficiency, the charging rate of an LCC is 50 times that of a lithium battery and 250 times that of a lead-acid/nickel-chromium battery, which means that the charging time will be very short. LCCs belong to super-fast charging, and it only takes 1 minute to charge, so there is no need to wait for charging. The discharge rate of an LCC is also higher, which can reach 50 times in its transient state and 20-30 times in its continuous state, so it can provide greater power output, work in a very wide temperature range, and can be charged and discharged at -40-65°C. The charge and discharge times of LCCs can reach 50,000 times, and the battery life can reach more than 5 years, which is very long. Therefore, in practical applications, it can be said that there is no need to replace the battery and it can be used for life.
In recent years, with the development of society, the peak-valley difference between daytime and nighttime power demands has been increasing. At present, the peak-valley difference of the daily average power demand in many cities exceeds 60%. In order to truly achieve the goal of energy saving and emission reduction, efforts should be made to solve the main contradiction of the huge peak-valley difference between power demands during the day and night, which is an important application field of LCC modules.
Energy storage module system supporting high voltage and high current
The energy storage module system used in wind power/heavy industry can be used as an auxiliary energy storage system for various wind power generation facilities, which can significantly improve the power quality of micro smart grids, provide reactive power support for micro smart grid systems, have high output power, support high voltage (≧500V) and high current (~1000A), and have the characteristics of long service life and being maintenance-free, as well as being capable of being used in a modular way according to different voltage or capacity requirements.
The (ANGA POW®) module introduced by Manyue Technology has ultra-low internal resistance and ultra-high power (≧200 kW), supports more than 500,000 charging and discharging times, integrates the supercapacitor management system (CMS), and supports voltage balancing among cells, over-voltage and temperature monitoring signal output, as well as an RS or CAN output interface. The module structure is solid and compact, fully enclosed, and splash- prevention.
The (ANGA POW®) module supports a rated voltage of 129V, rated capacity of 62F, surge voltage of 134.4V, leakage current of ≦10mA, DC ESR (equivalent series resistance) of ≦20mΩ, the maximum charge/discharge current of 640A, and standard charge/discharge current of 32A, and can work at an operating/storage temperature of -40°C ~ +60°C. With a size of 644*465*285mm, it supports IP41 class of protection and weighs about 51kgs. It is an ideal auxiliary ESS for various wind power/heavy industrial applications.
Conclusion
With the rapid development of the EV and ESS market, the application requirements of batteries are increasing day by day. How to improve the operation efficiency and safety of batteries has become a major issue in battery applications. This article introduces various solutions for various battery applications, which will enable you to further understand the various devices and modules needed for battery applications in charging, discharging, and management, and facilitate having a reference for product design. If you have further requirements, please contact Arrow Electronics for more information.