According to the Washington Post, an average electric car (EV) needs 30-kilowatt hours to run 100 miles. This figure is the equivalent of the energy amount an average American home requires daily to run electric appliances, from computers to the AC.
The EV stores the required energy in high-voltage batteries that require top-notch EV battery insulation.
Consequently, there is a need to find the best materials to guarantee the perfect insulation for EV lithium-ion batteries. Using the best insulating material—in the form of foam, liquid, or film—is a safety measure for drivers and the vehicle since it provides 100% protection from electrical discharges.
Are you unsure about the quality of insulation material you require? Read below to understand the science and logic behind EV battery insulation materials.
Are EV Battery Packs Insulated?
Battery packs are used extensively in electric vehicles. The life, aging, and safety of battery packs are significantly related to their thermal behaviors.
The packs have increasing requirements regarding their runaway mitigation strategy. Generally, battery packs in an EV comprise cells and modules, for which electrical insulation is a critical factor.
Electric insulation strength is one of the major parameters relating to a power semiconductor module’s reliability and safety. Breakdown of the electrical insulation causes module failure. Therefore, it makes sense why vehicle manufacturers constantly seek insulation solutions for EV battery packs.
How Do You Insulate Lithium Batteries?
Lithium batteries used in EVs produce high heat amounts while charging or in use. Automatically, insulation is due to help maintain a temperature balance for these batteries. ResearchGate lists the four major lithium battery thermal management approaches to include:
- Air cooling
- Liquid cooling
- Phase Change Materials (PCM)
To ensure the thermal insulation materials meet every requirement (weight, space, etc.), they need to share the following characteristics:
- Thermally insulating
- Electrically insulating
- Flame retardant
When insulating lithium batteries, you need to pay attention to:
- Cell internal insulation: Lithium battery cells are rechargeable accumulators containing electrodes and liquid electrolytes. However, the cell manufacturer is responsible for the cell’s internal insulation next to the casing that holds the cell energy.
- Insulation between cells: Manufacturers add an extra insulation layer between cells to ensure proper electrical insulation. The extra layer also ensures no electric arcs between cells, thus guaranteeing proper battery functioning.
- Insulation of modules: The battery cells help to ensure proper electrical insulation function. The films between modules function as a thermal barrier to contain the spread of a possible fire outbreak and avoid thermal runaway.
You also need to pay attention to key considerations when choosing materials for battery insulation.
Important Considerations When Selecting Battery Insulation Materials
Selecting insulation material goes beyond an impressive electric thermal insulation performance. Below are additional factors to consider when choosing insulation materials for EV batteries.
1. Thickness (thickness-to-efficiency ratio)
What are the dimensions of the interface gaps where the thermal interface materials will be put?
Contact is fundamental to reducing thermal impedance within the gap. For battery manufacturers, the film’s thickness is a major consideration regarding electrical insulation to ensure a perfect balance between the battery’s compactness and the energy density the film can contain.
The thermally conductive materials should be able to withstand extreme temperatures and external force. Can it withstand the physical exertion it will experience within the batteries?
3. Cost to Function Ratio
Electric insulators range in effectiveness and price, with the highly effective type being priced higher. However, EVs and their internal components should remain affordable to attract potential buyers. Regardless, there ought to be a reasonable balance between efficiency and costs.
4. Dielectric Strength
The material should show the dielectric strength necessary to meet rigorous electrical barrier and insulation requirements.
5. Material Weight
The material weight is also an important factor. The more the insulating material’s weight, the more the weight it places on the vehicle, thus limiting its full potential.
6. Vibration Resistance
The lithium batteries and EV battery insulators will constantly be exposed to noise and vibration levels due to the vehicle operation. As such, the material should be comfortably capable of withstanding some physical stress.
7. Chemical Resistance
How resistant is the material to chemicals since it will likely be exposed to chemicals during vehicle operations.
What is the Main Objective of Thermal Management of a Battery Pack?
The Battery Thermal Management System’s primary objective is to hinder accelerated battery deterioration by managing the heat that its components generate.
The end goal is to ensure the battery continues operations under optimum temperature conditions specified by manufacturers.
Additional benefits of proper battery insulation include:
- Avoiding fire outbreaks: Possible causes of fire outbreaks in EV lithium-ion batteries include internal short circuits, excessive temperatures, and violent shocks. To avoid such occurrences, manufacturers insulate cells electrically from one another, add thermal breakers on modules, and ensure the battery packs are airtight, watertight, and shock-resistant.
- Battery assembly and module manufacturing require human labor to handle the cells: Unfortunately, failure to insulate charged components may result in violent discharges. Therefore, insulation materials help to minimize such occurrences. Generally, thermal management ensures safety for drivers, manufacturers, and electric vehicles.
The bottom line for thermal management is the avoidance of the negative financial effects.
Thermal Management in EV
A developed battery thermal management system combines thermoelectric cooling, liquid cooling, and forced air cooling.
As a concept, thermal management in electric vehicles takes the necessary measures to ensure temperatures within the vehicle system, mostly the batteries, remain relatively constant. Thermal management in EVs is the number one measure in ensuring safety for electric vehicle manufacturers and users.
How Do You Insulate a Battery Box?
There are multiple manufacturer-recommended materials that can help in insulating EV batteries. Insulation foams are the best way to achieve great results for thermal insulation.
You can isolate battery components from each other by using elastomeric forms like silicones, which are reliable options due to their intrinsic heat resistance properties. You can also check with the cell manufacturer for the best advice on insulating EV batteries.
EV Battery Insulation Solutions
Are you looking for a reliable partner and expert in electric vehicle battery insulation? Lamart Corporation is an industry-leading expert in providing various technical solutions. Our experts can help you understand battery insulation and further help you choose the best, practical solutions for your needs. Contact us to discover more.