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Electric Vehicle Batteries: Protecting Against Collision and Thermal Runaway

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March 07, 2022

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Blog | eMobility | EV Battery | Gaskets and O-Rings | Insulation and Shielding

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electric vehicle thermal runaway | electrical insulation | EMI/ RFI Shielding | ev battery thermal runaway. thermal runaway lithium ion battery | preventing thermal runaway

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Battery charge range historically challenged consumer adoption of electric vehicles (EVs). But innovative EV designers have found creative ways to make drastic battery charge range improvements and the electric vehicle industry continues to grow at a rapid pace with EV adoption significantly increasing. Over the last ten years, some estimates suggest that average electric vehicle battery range has increased more than fourfold. This increase in power brings key thermal challenges. Increasing EV adoption elevates the need for more ruggedized EV battery designs to extend lifetime performance and control or reduce warranty claims. Boyd’s innovative team of experts and design leaders are at the forefront of solving these challenges. We’re helping pioneers in this space accelerate innovation. Our engineers develop integrated engineered material solutions that enable smaller, ruggedized, lighter, more efficient, and more reliable batteries with faster charge cycles for greater electric vehicle range, safety, and reliability.

What is Battery Thermal Runaway?

Lithium-Ion thermal runaway occurs when heat generated by a battery exceeds the amount of heat being dissipated. Unmanaged heat can generate an uncontrolled chain reaction to surrounding batteries and li-ion battery cells. When li-ion thermal runaway isn’t handled properly, batteries overheat, produce smoke, and combust. Multiple factors cause thermal runaway, some include internal and external short circuits, overcharging, high ambient temperatures, rapid cycling, and battery age. Effective protection is vital not only to an electric vehicle battery, but also to vehicle occupant safety.

How to Prevent Li-ion Thermal Runaway? Battery Thermal Runaway

Electric vehicle and battery manufacturers design preventive and containment strategies around EV battery thermal runaway. Thermal runaway prevention begins with optimized EV battery design. Thermal runaway protection is enhanced with specialty materials and components that reduce the probability of a thermal runaway event and protect against thermal runaway propagation if a catastrophic event were to occur.

Li-ion battery cell-to-cell integrated multi-layer complex assemblies protect against thermal, environmental, and mechanical factors that cause battery thermal runaway. These multi-functional laminations proactively mitigate hot spots, insulate heat from passing to other cells, and also absorb impact, vibration, and movement in the battery.

Smart designs help prevent thermal runaway by isolating catastrophic battery events when they happen. Incorporated flame or heat barriers in cell design quickly isolates extreme heat or fire in the unlikely event battery safety design features fail to prevent cell-to-cell propagation. Integrated EV battery thermal runaway protection solutions feature heat spreaders with compression pads and flame-rated electrical insulation to isolate li-ion battery cells.

Why do Electric Vehicle Batteries Need to Be Ruggedized?

Harsh environmental conditions are an everyday reality for electric vehicles. EV batteries and components need protection during operation to extend performance lifetime and reduce warranty claims. Ruggedized EV batteries can withstand and perform better against collision impact, ongoing shock and vibration, extreme road conditions, and extreme weather conditions.

How to Protect EV Batteries? Ruggedize and Waterproof the Battery Compartment

Sealing the EV battery enclosure protects the battery and cells against liquid, gas, and particulate intrusion to ensure long battery life. Leverage specialty materials and smart gasket design to both waterproof and seal EV battery housings, eliminate noise, vibration, and harshness (NVH), and optimize reliability and performance. Boyd’s EV battery housing seals are designed for simplified customer assembly, design for manufacturing (DFM) throughput, material optimization, and are ruggedized to withstand harsh road conditions over the life of the vehicle.

Battery Cell and Battery Module

Protect EV batteries against collision impact, harsh road conditions, and temperature extremes with rugged, resilient compression pads. Battery compression pads layer between battery cells and around the battery module to compensate for swelling forces and mechanical shock, friction, and extreme road vibration. They act as a battery impact protection barrier to enhance consumer safety and reduce battery-related warranty costs. Boyd’s wide variety of closed and open cell foam options are highly resilient and meet the needs of many different temperature and environmental exposure applications.

Design Shields Around the Battery Module

Improve battery performance, safety, and reliability with EMI and RFI shielding. EMI Shielding prevents both the input and output of radiofrequency interference (RFI), electrostatic interference (ESD), or electromagnetic interference (EMI), all of which are highly prevalent in complex electrical systems in electric vehicles. EV battery EMI shields protect battery performance and prevent electronic malfunction in critical safety systems. Boyd’s conductive foams, elastomers, adhesives, foils, and more are designed to mitigate this interference and shield unwanted signals, improving reliability and efficiency in EV batteries.

Wrap EV Battery Cells with Electrical Insulation

Wrap li-ion battery cells and EV battery modules with high performance electrical insulators. These rugged insulation layers prevent spark voltage between internal critical components that can lead to battery shorting or fire. They also isolate and act as flame barriers in the unlikely scenario of a catastrophic event. Boyd’s electrical insulators and isolators are flame rated up to FR V0, helping you proactively design to prevent electrical EV battery fires from occurring, or to isolate li-ion battery cells if they combust.

Thermal-Interface-Materials-EV-Batteries-2

Dielectric Adhesives on Busbars

Protect flexible, printed circuits in EV battery assemblies to extend battery lifetime and maintain performance. Dielectric adhesives electrically insulate busbars with high heat resistance and flame protection. Busbars feature precision designs and dielectric adhesives must be converted with tight tolerances for precision through-hole placement. Boyd’s dielectric materials and adhesives are tested for breakdown voltage and dielectric strength requirements using GB/T 1408.1-2016 and ASTM D3755 test methods.

How to Maximize Electric Vehicle Battery Power Efficiency and Performance?

Minimize Thermal Resistance with Thermal Interface Material

Improve heat transfer between the battery cold plate and battery module by minimizing thermal resistance between these two surfaces. Thermal Interface Materials (TIMs) minimize heat flow resistance between surfaces, more efficiently moving heat away from sensitive EV batteries into the liquid cooling system through the battery cooling plate.

Boyd’s thermally conductive tapes, gap fillers, thermal pads, films, phase change materials, and thermal grease maximize battery liquid cooling system performance by more efficiently moving heat from the battery to the liquid cold plate.

Whether it’s protecting EV batteries, creating smart displays and telematics, optimizing EV charging, elevating EV brand identity, and more, Boyd helps eMobility designers and market leaders accelerate innovation. For more information about Boyd’s EV battery solutions, watch our video below. For specific questions about your application, reach out to our experts.