Covestro Polyurethane Launches HP-RTM Polyurethane Battery Pack Upper Case Solution

Latest News:As the market share of electric vehicles continues to increase. The safety, flame retardancy and lightweight requirements of batteries are becoming increasingly important. The polyurethane battery pack upper case solution developed by Covestro’s Custom Polyurethane Business Unit for high-pressure resin transfer molding (HP-RTM) process has now completed the battery pack’s severe material grades and final battery packs Various tests at the finished product level have been carried out, and mass production has been realized. This makes Covestro the first material and solution supplier in the world to achieve mass production of this technology.

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This solution has great advantages for improving the flame retardancy, safety and light weight of the upper case of the battery pack. At the same time, it also brings cost controllability and supply chain stability after large-scale production. It is a solution with outstanding comprehensive performance.

In recent years, many electric vehicles have suffered spontaneous combustion accidents caused by thermal runaway, which has caused OEMs to attach great importance to the safety of battery packs. The flame retardancy of the housing that houses the battery modules and blocks the underbody becomes particularly important. In addition to the current industry requirements, the material of the battery shell meets the requirements
UL94 V-0 flame retardant grade,
The upper casing is also required to pass a rigorous external fire test. The glass fiber reinforced polyurethane composite resin developed by Covestro will form an inert gas protective layer and a carbonized layer on the surface of the material when exposed to fire. At the same time, a high proportion of glass fiber is used as an inorganic non-metallic material to prevent the flame from continuing to burn, ensuring the safety of the upper casing of the battery, and does not require additional costs and processes for fire-resistant coatings.

Polyurethane composite materials have passed the international EU REACH, ROSH and GB38031-2020
Testing of mechanical properties, high temperature and humidity aging, xenon lamp aging, acid and alkali resistance, high temperature resistance and insulation properties.


The weight reduction of the battery pack can reduce the carbon emissions of the whole vehicle and increase the cruising range of the electric vehicle, killing two birds with one stone. HP-RTM with Covestro
The upper case of the battery pack made of polyurethane composite material, thanks to its strong physical properties and low density advantages, can easily realize the mass production of thin and light battery case solutions.

The average thickness of the entire shell is about 1.5mm, and the thinnest can be
0.8mm. While ensuring light weight, it can also maintain the characteristics of high strength and high toughness, which has outstanding advantages in all current non-metallic solutions.

✔ 60% lighter than strength steel

✔ 50% lighter than SMC

✔ 20% lighter than aluminum alloy

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Compared to prepreg process, HP-RTM
The process realizes the automation of the layup to a considerable extent by optimizing the design of the fiber layup, which greatly improves the production efficiency. Moreover, its mold costs, operating labor, operating costs and quality stability have been greatly improved.

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The process only needs to arrange a small number of stations in the pre-forming stage. At the same time, one glue injection machine is used with two presses in the “one-for-two” design, which shortens the product forming cycle to improve production efficiency and ensures cost controllability. . In addition, the storage of prepreg has strict production management requirements for temperature and humidity, and
The process route of HP-RTM is more forgiving.

Covestro Baido® HP-RTM resins

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Glass fiber reinforced polyurethane composite material is an ideal material choice for achieving lightweight and flame retardant electric vehicle battery packs. Covestro offers polyurethane systems dedicated to HP-RTM technology: Baydur®
) HP-RTM system, with highly tunable properties, suitable for combining with other materials to form composite materials to enhance the required properties and meet the needs of many applications.

In addition, combining the advantages of weight, high efficiency, and free of fire-resistant coatings, HP-RTM polyurethane solutions are outstanding in terms of cost performance, and the overall cost is greatly reduced.