Need for innovative EV battery pack solutions to ensure safety and efficiency

By: Ritesh Patterson, Managing Director, Performance Plastics, Saint-Gobain India

India is a growing market for the automotive industry – in 2021 it was 5th in the world and is expected to be 3rd by 2030. India is estimated to have stronger and faster adoption of vehicles electricity (EV) by 2030 with an annual growth rate of 26%.

Industry challenges and effective battery solutions

The efficiency of an electric vehicle really depends on its battery, and lithium-ion batteries are the most common battery choice. However, they have the disadvantage of limited energy storage capacity. This reduces the distance that electric cars can travel before needing to be recharged. Since each recharge cycle slightly decreases the overall capacity of the battery, these batteries have a relatively short lifespan and degrade rapidly as they age.

To address these existing battery challenges and support the industry’s dramatic growth, significant improvements in EV battery technology are needed. Saint-Gobain’s battery pack solutions aim to provide protection for electric vehicle battery packs by providing materials that reduce manufacturing complexity while improving overall battery life.

  1. Compression pads for Pouch/Prismatic cell

Lithium-ion (Li-ion) battery is a type of rechargeable battery used in electric vehicles (EV), it is different from the battery used in consumer electronic batteries in terms of chemical chemistry and their high density of energy per mass. Three types of lithium-ion battery cells can be used in electric vehicles: cylindrical, prismatic and pouch; Among these, the soft-bodied pocket style is the most popular due to its highly efficient packaging. In operation, pocket cells are more susceptible to heat swelling compared to prismatic cells. In both cases (pockets and prismatic cells), this swelling must be managed to optimize performance. Products such as compression pads help maintain the integrity of the pack by limiting relative movement between cells under shock or vibration and providing compliance to swelling cells when subjected to force. The elastic characteristics of the foam found in compression pads provide a constant deflection force over a wide range of compression and temperature – a property called Compression Force Deflection (CFD) and this is where Norseal® foams can help achieve these properties consistently throughout the life of the battery.

  1. Thermal Runaway Protection Pads (TRP) and Firestop Foams (FS1000)

Given the current market events, the market is constantly striving to include fire safety aspects in the battery. Thermal runaway shielding materials can serve the dual purpose of fire mitigation and compression. The TRP and FS1000 help minimize the spread of fire between cells/modules in a battery with their unique property called intumescence – to block flames, hot gases and smoke in the event of a fire. They are also waterproof for optimal acoustic and thermal insulation. TRPs are flexible compressible materials providing fire suppression, thermal insulation and padding, while FS1000 is a fire rated flexible sealing foam that is stretchable and fire resistant, blocking smoke, air and the water.

  1. Thermal management with thermal interface materials

Considering both efficiency and safety criteria, thermal resistance and thermal management are becoming increasingly important in the design of electric vehicles (EVs) and their components. It is important to maintain the temperature of the pack as it will be gradually controlled as manufacturers and drivers try to get the most out of a battery pack. The best way to transmit energy between cooling devices and battery components is through the use of thermal interface materials (TIM). The thermal interface material is a soft silicone elastomer that is ceramic filled, inexpensive, sticky in nature and performs exceptionally well under compression. Key issues such as overheating, electrical shorts and vibration can be solved by multi-functional silicon-based technology i.e. from the Thermacool range.

  1. Unique gasket materials for IP67 pack sealing

Keeping the battery sealed from the outside is important to ensure efficient performance and longevity of an electric vehicle. Battery enclosure options with materials such as foam gaskets, silicone foam rubbers, butyl coated PVC and PUR microcellular foams seal the batteries from the outdoor environment with a low compression package and solutions flame retardants that guarantee the protection of the battery.

Government push to improve electric vehicle battery performance

The Electric Vehicle sector is at the forefront of sustainable mobility. Although in its infancy in India, the industry is showing massive growth and attracting strong consumer demand. The government, too, provides incentives to accelerate its progress, performance and infrastructure. One of the main areas of interest is to help address today’s electric vehicle battery challenges in terms of safety and efficiency. The Bureau of Indian Standards (BIS) has therefore formulated performance standards for EV batteries related to battery cells, battery management systems, on-board chargers, battery designs and thermal spread. These new regulations should come into force from October 1, 2022.

Also, following a series of fires in the recent past, efforts are being made to create safe and long-lasting batteries. For example, the IPx7 rating test verifies electric vehicles meet specific requirements to ensure there are no fires or explosions, and the thermal spread test verifies user safety. and bystanders of a vehicle in the event of a thermal track in the battery system.

It is crucial to build battery packs that adhere to such rigid testing and performance standards.

The Road Ahead – Collaborative approach

The need of the hour is for companies with materials expertise to work with EV OEMs and battery manufacturers to develop products for these applications. Organizations such as Saint-Gobain Tape Solutions Business have worked with EV battery manufacturers locally and globally to deliver product solutions that ensure increased safety and efficiency.

Author: Ritesh Patterson, Managing Director, Performance Plastics, Saint-Gobain India

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