Battery Management System (BMS)
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How to design a battery management system
Infineon integrated circuits and designs help you to layout your Battery Management System. Careful design considerations on charging and discharging processes on battery protection and cell monitoring will support you throughout your design.
Infineon‘s solutions and design resources for a battery management system, help you to overcome your design challenges and support your success in developing more efficient, longer-lasting and more reliable battery-powered applications.
From engineers to engineers, our tools will support you every phase of your design, from comparing the different products to simulations, and of course ready to use reference designs.
Depending on your application constraints you can check different system architectures for battery management systems and find the supporting product families of Infineon for
- Multi-module, high-voltage batteries
- Single-module, medium voltage batteries (more than 12 cells, higher 60V)
- Single module, low voltage batteries (more than 12 cells, below 60V)
Discover below interactive block diagram for battery management system and find Infineon‘s recommended products for your Battery Management System and learn more about the function blocks below:
The TLE9012AQU is a multi-channel battery monitoring and balancing system IC designed for Li-Ion battery packs used in automotive, industrial and consumer applications. TLE9012AQU fulfills four main functions: cell voltage measurement, temperature measurement, cell balancing and isolated communication to main battery controller. Additionally, TLE9012AQU provides the necessary diagnosis tools to ensure proper function of the controlled battery.
› Robust communication without need of transformers or common mode chokes
› Best in class voltage measurement accuracy even after soldering thanks to stress sensor technology
› Integrated diagnosis easing functional safety design
› Integrated UART communication for systems with a microcontroller on local ground
For a powerful combination use the TLE9015QU. It is a battery monitoring transceiver IC designed for connecting several TLE9012AQUdevices in a daisy chain inside a Li-Ion battery. By means of its two UART and iso UART interface pairs it can support ring communication improving the availability of the system by a low cost.
It also enables bidirectional information flow by including an error management unit including several inputs and outputs that are programmable on each TLE9012AQU.
- Enables a controlled emergency disconnect in case of over-charging, short-circuit and thermal run-away
- Drives system-level benefits for solid-state based implementation like
- Pre-charging of DC bus @ main inverter(s) for traction motor(s) w/o additional components
- Active limitation of fault currents
- Extended lifetime due to higher number of switching cycles
- Reduced wiring diameters because of by orders of magnitude faster disconnect in case of detected overload / short-circuit
- Programmable switching characteristic
- Fastest possible crash protection
- More than 40% reduction of electrical losses for solid-state based implementation compared to electro-mechanical relays
- High-voltage superjunction MOSFET switches for low-frequency switching applications—600V CoolMOS™ S7
- Isolated single channel driver for high voltage applications 1EDI2002AS
- Isolated single channel booster 1EBN1001AE
Find more details on battery protection topologies here.
In battery management systems (BMS) a compact and reliable solution that powers the entiere system is required. Several components can be integrated, extreme battery fluctuations are managed and requirements of the latest network interfaces and automotive security are met with Infineon‘s portfolio of Power Management Ics (PMICs).
The PMICs support comprehensive power supply for the system by a small form factor and complement solutions based on Traveo™, AURIXTM and PSoC MCU families. Boost function integrated in the PMICs avoids system blackout under extreme battery voltage fluctuations. Low quiescent current of the PMICs reduce standby current of always-on functions. The PMICs comply with AEC-Q100, and rich system safety functions help to comply with modern vehicle ECU requirements.
Recommended PMIC for BMS:
- S6BP20x series (S6BP201A, S6BP202A, and S6BP203A) PMICs are one-channel buck-boost DC/DC converters for automotive and industrial applications.
- S6BP501A and S6BP502A PMICs are 3-channel output power management ICs (PMICs). They come with a buck controller and a buck converter, as well as a boost converter, offering a single chip 5.0V, 3.3V, and 1.2V power source. These PMICs have quiescent current as low as 15μA
- S6BP401A PMIC is a single-chip power management solution which has a 6-channel power output. It includes a 4-channel DC/DC converter and 2-channel LDO. Integrating output setting impedance and phase compensation circuits internally for all channels, the S6BP401A reduces the PCB size and bill of materials
- OPTIREG™ PMIC products are providing integrated, multi-rail power supply solutions. The family is offering high efficient voltage regulation including pre- and post-regulator architectures with DCDC-, linear, and tracking regulators. Beside power supply, additional monitor- and supervision features and functions are integrated. Check the OPTIREGTM switcher simulation tool to calculate efficiency and stability!
The TLF35584 is a multiple output system supply for safety-relevant applications supplying 3.3V-μC, transceivers, and sensors by an efficient and flexible pre-/post-regulator concept over a wide input voltage range. The wide switching frequency range allows optimization in respect of efficiency and usage of small filter components. A dedicated reference-regulator supplies the ADC independent from μC-load steps and acts as tracking-source for the 2 independent sensor-supplies. The flexible state
The battery charging system is built to recharge the high voltage battery from the AC grid. In cars this system is the on-board charging unit. By increasing the battery capacity and the energy efficiency of the electric components the used battery voltage classes tend to become standardized at approx. 450 V with a trend towards higher voltages. This supports faster charging times and enables lighter cabling within vehicles. The trend towards fast charging also impacts on the power range demanded from topologies, therefore new designs trend towards 11 kW or even up to 22 kW. Today typically there is a unidirectional power flow from the grid to the battery, but there is also bidirectional use cased like a battery to load or battery to grid.
One of the basic tasks in battery charger is the regulation of battery voltage and current without exceeding the temperature limits. This requires a control loop which involves measurement of the battery parameters (voltage, current and temperature) and controlling the PWM duty cycle that drives the external power network. PSoC with its precision ADC (max 14 bits) - implemented using analog blocks, PWM - implemented using digital blocks and a processor core forms such a control loop required for regulation. Other algorithms like cell balancing and fuel gauge can be implemented using a firmware logic.
The advantage of using PSoC lies in the implementation of custom protocol for charging the battery and integration of other functions like Capsense, Segment LCD drive etc which are not possible when using dedicated battery charger ICs.
Active thermal control is a key element within modern Li-Ion battery packs as cell temperature for charging has to be kept between 0 to 45°C and for discharging between -20 to 60°C; operation outside these ranges results in accelerated aging, reduced capacity or even full damage of the battery.
- embedded motor controllers enable efficient motor control with inbuilt diagnostic functions for efficient operation of internally controlled fans, pumps or valves for thermal control purposes of pack. Smallest package form factor and a minimum number of external components are essential for integration close to motor.
- 32-bit uController with embedded non-volatile memory, analog/digital peripherals, LIN interface and integrated current-controller bridge driver for power transistors
- DC and BLDC motors are operated via optional interfaces for half-, H- or 3-phase bridging circuit
AURIX™ microcontrollers from Infineon secure communication between the off-board charger and the BEV or PHEV being charged. They also protect the in-vehicle communication network. These advanced microcontrollers provide all the safety and security features required for OBC applications. Infineon’s AURIX™ 32-bit microcontroller family (SAK-TC275TP-64F200N DC, SAK-TC265D-40F200N BC, SAK-TC234LP-32F200N AC and SAK-TC224L-16F133N AC) provides a scalable portfolio that supports automotive safety standard ISO 26262. The embedded hardware security model (HSM) enables secure communications. AURIX™ highlights include an optimized peripheral set including ADC & timers for electromobility applications.
Isolation monitoring is a key for high-voltage batteries. In combination with short circuit and overload current measurements the voltage of the high-voltage DC+/- lines is continuously measured against the pack’s mechanical housing and the surrounding chassis. The existence of high performance current sensors also allows for additional use of the performed current measurements in the context of Coulomb counting, state-of-charge, depth-of-discharge calculation in battery monitoring or advanced impedance spectrocopy in battery diagnostics.
Besides current, voltage and temperature measurements advanced analytics are performed on pack-level with respect to thermal, electrical and mechanical strain: Highly accurate pressure sensing allows to observe the possible extension of cell housing as a result of overload/-charge condition or detection of mechanical impacts on the pack‘s mechanical structure. Sensing of evaporated CO2 from the cell’s electrolyte as a result of cell aging or overstress could be a vital indicator for battery health. Finally, a combination of the pressure of condition sensors allows for the detection of unauthorized pack manipulations e.g. for modification or replacement of cells by measuring variations in pressure or 3D magnetic structures.
Why are battery management systems (BMS) needed and how do they work?
Battery management systems (BMS) are electronic control circuits that monitor and regulate the charging and discharge of batteries. The battery characteristics to be monitored include the detection of the battery type, the battery voltage, the temperature and the voltages of the battery cells, the battery capacity, the state of charge, the power consumption, the remaining operating time, the charging cycle and some more characteristics.
Tasks of smart battery management systems (BMS)
The task of battery management systems is to ensure the optimal use of the residual energy present in a battery. In order to avoid loading the batteries, BMS systems protect the batteries from deep discharges, from overvoltages, from too fast charge and too-high discharge current. In the case of multi-cell batteries, the battery management system provides for battery balancing, which is reflected in the fact that the different battery cells have the same charging and discharging requirements.
In this training you will:
- Identify the aspects covered by the battery management systems (BMS), their main components and their function
- Recognize Infineon’s main components for battery management applications and the key features and benefits of Infineon battery management devices
Getting the most out of batteries. By the end of this decade, the majority of new cars sold around the world is expected to have a partially or fully electric drivetrain. Battery management systems have a great impact on the range, cost and service life of electric vehicles, which makes them a key success factor for this mobility revolution. Furthermore, they play an essential role when it comes to second-life concepts that allow former EV batteries to be used as flexible storage for renewable energy, for example. Dr. Clemens Mueller exclusively explains in-depth market trends and challenges, provides details on Infineon products and solutions, and introduces the new BMS-IC TLE9012AQU.