Feature: Thermal management
The most common type of solar inverter is the string, typically used with a group of adjacent solar panels
combine thermal management with mechanical stress relief and vibration dampening. In battery-pack modules with cylindrical
provide excellent adhesion to a wide range of materials and strategically support component leads during vibration. Tey can replace mechanical attachments such as fasteners and are used for the structural bonding of capacitors, connectors and other electronic components. Silicone staking adhesives also provide dielectric insulation and UL 94 flame resistance.
Better BESS protection Like PV inverters, BESS are a key renewable energy technology – they store energy from sources such as the Sun and then release power to the network when required. Lithium-ion (Li-ion) batteries are typically used because they are the most economically viable storage technology available. However, they are susceptible to thermal runaway, a condition that causes a battery cell to enter an uncontrollable, self-heating state, resulting in high temperatures, smoke and even fire. In battery-pack assemblies, thermally-
conductive silicones are used in modules with prismatic or pouch cells, and in modules with cylindrical cells. Along with thermal stability and high-temperature and flame resistance, these advanced silicone materials can prevent the spread of fire whilst protecting sensitive electronics against outdoor environments. In modules with prismatic or pouch
cells, thermally-conductive silicone adhesives provide reliable adhesion and are used in component staking. Products
come in a range of thermal conductivities (0.8-3.3W/mK) and have a high rate of elongation, to relieve the stresses caused by different rates of thermal expansion among electronic components made of different materials, including metals, ceramics, plastics and glass. And, because these adhesives can achieve bond line thicknesses between 40-150µm, they can accommodate a range of thinner gap sizes. Gap fillers may be used for larger gap tolerances, typically from 150µm- 5mm, when high adhesion is not required. Tese thermally-conductive silicones have limited adhesion but offer advantages in terms of processing and properties. For example, gap fillers support room- temperature curing and are reworkable. Tey are also easy to remove for repair or recycling. Although gap fillers do not support primer-less adhesion, they are characterised by highly-repeatable metering and fast, accurate dispensing without aſter-flow. During product assembly, thermally-
conductive silicone gap fillers can fill complex geometries when compressed. With their excellent wetting properties, they spread readily across substrates and remain in place, even in the vertical position. Tey also provide excellent interfacial contact for reliable cross-joint strength and durable thermal dissipation. Tey are available in thermal conductivities ranging from 1.5-5.0W/mK and, because they are soſt and compressible, they
cells, Li-ion batteries are arranged in an array and spaced closely together. Termally-conductive silicone adhesives attach the individual cells to a substrate, and gap fillers can be used between individual batteries. To fill the spaces between cells, thermally-conductive silicone encapsulants and foams for fire protection may be used instead. Both materials provide important advantages. For example, thermally-conductive silicone encapsulants provide dependable protection both during normal operations and in the event of a cell failure. Tese materials are strong and fire resistant, but they are also flexible enough to provide mechanical stress relief and vibration dampening. With their low moisture uptake, they also provide electrical isolation. Silicone foams offer a lightweight,
fire-resistant alternative to thermally- conductive silicone encapsulants but have a much lower thermal conductivity, typically around 0.05-0.1W/mK. Generally, silicone foams are a better choice when there are differences in compressive pressure or when thermal insulation is needed to limit heat transfer to the adjacent cell during an event. Compared with all the other products described here, silicone foams are the thermal and electrical insulators that are most compressible and have the lowest density.
A more sustainable future As demand for renewable energy technologies grows, companies that design and manufacture solar inverters and battery energy storage systems will need materials that can meet multiple requirements. Te precise application of thermally-
conductive silicones and other advanced materials reduces waste, and curing at room temperature or with moisture reduces energy costs. Like the renewable energy technologies
that they support, thermally-conductive silicones are an integral part of a more sustainable future.
www.electronicsworld.co.uk November 2023 39
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54
