pulse-networking-battery-management-systems

    Using Battery Management Systems for EVs, HEVs, & PHEVs

    by Pulse Networking Team

    pulse-networking-battery-management-systems

    Early electric vehicles (EV), hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs) used either lead-acid batteries or NiMH batteries for storage.

    However, these batteries were not optimal: EVs, HEVs, and PHEVs require impressive energy storage that even NiMH batteries, with a 68Wh/kg specific energy, aren't capable of.

    In search of higher energy-efficiency, many manufacturers have turned to lithium-ion batteries, such as lithium-titanate, lithium-phosphate and lithium-manganese, for electric vehicles. Optimal and safety use of these batteries requires a battery management system (BMS).

    Because each BMS function takes energy, BMS designers must prioritize designs. Many BMS do not log data, for example, and they may fall short when estimating the battery's present state or overall state.

    However, one of the most critical functions is protecting the life of the EV's battery. Safety is vital in today's modern car. Due to the high energy contained in the battery and the risk in the event of a collision or short circuit, safety is a major consideration when choosing a battery management system.

    A BMS must be linked to all battery components, as well as the vehicle's computer. The BMS will take several sensor readings, including but not limited to:

    • Sensing the cells' voltage and timing the battery's charging or discharging. This gives a battery indicator to the user, but more importantly, it prevents overcharging, which can result in a dangerous thermal runaway. This will include balancing individual cells within the battery.
    • Sensing and controlling temperature. Unusually high or low cell temperatures indicate serious problems in progress.
    • Sensing current. Abnormal current indicates a safety risk and provides vital data to algorithms that determine the battery's present state and overall health.
    • Detecting and reacting to ground faults.
    • Taking logs on unusual readings for real-time and later diagnostics.
    • Communication with other battery components.
    • Prolonging battery life, which is made possible by careful application of the items above.

    Design Challenges of Battery Management Systems

    Taking the many sensor readings listed above poses a design challenge, regarding the physical structure of the battery.

    Series- and parallel-connected cell structures both create accurate monitoring. Companies have traditionally used centralized, distributed and modular functions to meet the needs of BMS systems.

    While many portable electronics have sophisticated BMS systems, EV, HEV, and PHEV BMS have traditionally lagged behind these due to the complicated task of balancing the hundreds of high-powered cells in an EV's battery.

    Cell balancing often involves the development of new algorithms and more precise detection methods, although incremental design changes have assisted with cell balancing as well.

    Isolation is also critical, to protect delicate systems from batteries' high energy. That's why Pulse Electronics has designed isolation transformers and common-mode chokes for battery management systems. These isolate multiple high-energy cells from one another, to improve safety and overall function.

    Battery Management System (BMS) Components for Voltage Isolation, EMI Noise Suppression, Cell Protection, & Reliable Operation

    Pulse Electronics offers a wide range of isolation transformers and common mode chokes for use in electric vehicles and energy storage systems.

    All parts meet AEC-Q200 requirements for automotive applications, supports daisy chain connections, and large voltage differences within a single device.

    Features and Benefits:

    • Supports BMS isolation and EMI solutions
    • Supports serial Daisy Chain isoSPI, SPI and other signal isolation
    • Meets AEC-Q200 requirements for automotive applications
    • PPAP documentation upon request
    • IATF 16949:2016
    • Operating temp. -40C up to +150C
    • Multiple options for working voltages and voltage isolation
    • 15 Years working life on Isolation

    The following Pulse Electronics Battery Management System Components are available for product designers:

    Battery Management System Components

    battery-management-system-designer-kitFor networking devices used in small and large battery pack systems for serial port safety isolation and EMI noise rejection application.

    Applications:

    • Electric Vehicle
    • Energy Storage Systems
    • Data Center UPS
    • Solar energy storage
    • Green – Renewable
    • Marine

    You can purchase the parts by clicking the button below, or continue reviewing parts in the table and the schematic.

    Buy Now

    PART No.

    No. of Channel

    Working Voltage

    HI-POT Isolation

    Creepage Distance

    Center Tap

    Common Choke

    Operation Temp

    Supported IC

    HM1188NL 2 100Vdc 1500Vms - Yes Yes

    -40~125°C

    Linear Tech 6820/6804/6811

    HM1190NL 1 600Vdc 2500Vms - Yes Yes -40~125°C Linear Tech
    HM1331NL 2 1000Vdc 4000Vms - Yes Yes

    -40~85°C

    Linear Tech
    HM2100NL 2 1000Vdc 4300Vdc >10mm No Yes -40~125°C

    Linear Tech 6820/6804/6811

    HM2101NL 1 1000Vdc 4300Vdc >5mm No Yes -40~125°C

    Linear Tech 6820/6804/6811

    HM2102NL 2 1000Vdc 4300Vdc >8mm Yes Yes -40~125°C

    Linear Tech 6820/6804/6811

    NXP MC33664/33771

    HM2103NL 1 1000Vdc <4300Vdc >5mm Yes Yes -40~125°C

    Linear Tech 6820/6804/6811

    NXP MC33664/33771

    HM2106NL 1 1000Vdc 4300Vdc >11mm Yes No -40~125°C

    Linear Tech 6820/6804/6811

    NXP MC33664/33771

    HM2108NL 1 1000Vdc 4300Vdc >11mm Yes Yes -40~125°C

    Linear Tech 6820/6804/6811

    NXP MC33664/33771

    HM1236NL 1 600Vdc 3200Vdc >7mm Yes   -40~125°C<

    MAX17823/11068

    HM1237NL 2 600Vdc 2500Vac - Yes Yes -40~125°C

    MAX17823/11068

    HM1238NL 1 1000Vdc 4300Vdc - Yes Yes

    -40~150°C

    MAX17823/11068

    Schematics

    battery-management-system-schematics

    For more information on the Pulse Electronics Networking BU components, download the datasheet or purchase the parts directly by clicking below.


    Download Datasheet

    Buy Now

    Originally published January 2, 2018. Updated February 5, 2018.

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