- Batteries are an essential technology for all-electric and hybrid vehicles.
Electric vehicle adoption considerations virtually all revolve around the same thing: battery efficiency and safety, as well as the ability to charge it on a regular, easy, and rapid basis. This begs the question for any Battery Designer: What may genuinely restrict the efficiency of a hybrid and electric vehicles battery?
There are no enigmatic answers to this issue; every engineer understands that heat is the most important aspect to manage and regulate when developing the finest battery. As a result, heat management operations are critical procedures for EV manufacturers. But are you aware of all the obstacles you’ll have to overcome to master EV Batteries Thermal Performance?
The most common Thermal Management Challenge is keeping Electric Vehicle Batteries Cool.
We’ll concentrate on keeping battery heat variations to a minimum. To begin, let us remind ourselves why the battery is such an important technology for all EVs, HEVs, and PHEVs:
- They allow for efficient electrical power input in all sorts of EVs.
- During acceleration periods, they also deliver energy to all motors.
- Improve the autonomy and range of all EVs.
- They aid in the reduction of the size of all engines, including those used in HEVs that run on fossil fuels.
- Also, improves regenerative braking (friction heat converted into energy)
- They still need to be upgraded to overcome fundamental challenges that have slowed consumer adoption of electric vehicles:
- Concerns about safety
- Cost, weight, and volume are all factors that must be considered.
- Concerns concerning the dependability and durability of batteries
- Performance deterioration with time
Table of Contents
What is the Significance of Battery Temperature?
Before we go into the technical aspects of limiting battery temperature swings, let’s be clear about the number one priority in all power charging and battery-back systems: SAFETY! The reason for this is obvious.
First and foremost, designers and automakers have a responsibility to safeguard drivers and passengers from any dangers that might result in injuries or fatalities.
Second, because heat regulation is the most important aspect that might cause difficulties, it is the principal factor that current R&D is working on.
Here are a few things to think about to guarantee both security and performance:
- The battery’s electrochemical system must be precisely controlled.
- When the battery is recharged, it must be safe and efficient, especially in fast-charging mode, when heat is created.
- In challenging settings, such as high-speed driving, Summer heat, or stop-and-start urban usage, the battery temperature must be regulated to safe ranges.
- The driver interface and information system must contain dependable and unambiguous warning signals to ensure power and energy availability.
How to Handle Factors Affecting Battery Temperature?
The significance of managing heat is created not just by battery activity but also by external elements such as ambient temperature, which ranges from arctic to tropical. The following are the key points to remember:
To protect your battery system from the outside environment, work on thermal insulation from the beginning of the design process for your entire battery pack. Insulation foams are the only approach to accomplish good results in terms of thermal management materials because it’s all about insulating your battery pack from what might impact it from the outside (extreme heat or cold).
Consider the following heat-generation Elements while constructing a Thermal Management System:
But on the other hand, if you want to protect and regulate the heat created by the interior of your battery pack, you have two possibilities!
- Either you can insulate each component from each other, in which case elastomeric foams (such as silicones) are the ideal choice due to their inherent heat resistant capabilities as well as their lightness.
- The second alternative is to evacuate the heat, which is slightly more complicated due to the usage of a cooling system (cooling plate + cooling fluids). The purpose, in this case, is to transfer heat from the heated battery cells to the cooling plate. To get there, an appropriate Thermal Interface Material (TIM) between the two components is required.
The purpose, in this case, is to transfer heat from the heated battery cells to the cooling plate. To get there, having an appropriate Thermal Interface Material (TIM) in between the two parts is critical, but you should be aware that it will influence the overall lightness of the design since thermally conductive materials cannot be foamy textured: they are quite thick.
The key factor in insulating or dissipating heat is the Thermal Interface Materials (TIMs) used, which may be formed of a variety of materials in the form of pads, greases, liquid gap fillers, adhesives, and so on. Silicone is increasingly being employed as the material of choice, either alone in specifically formulated elastomeric silicone formulations or composites including specialized fillers.
What are the Thermal Performance Issues With EV Batteries?
Overheating Battery Cells and Thermal Runaway:
Cells exposed to high temperatures deteriorate over time, having a rapid influence on total battery performance and capacity. But it isn’t the worst-case scenario!
A battery pack contains hundreds of battery cells, all of which heat up beneath your feet while you drive. Assume that one overheated cell may interact with the others and spread the heat across an entire battery module.
Thermal Runaway is the name given to this occurrence. Thermal runaway may result in an unanticipated fire, which is something no battery developer wants to happen. That is why battery safety and thermal management are critical for either transmitting heat to a cooling system (thermal conductivity) or insulating each cell to restrict heat spread (thermal insulation).
External temperature change and thermal shock:
Thermal Shock is the condition of being subjected to abrupt temperature fluctuations. This challenge of protecting the battery from outside temperatures can be overcome by installing a proper thermal insulation system: around the battery modules (insulation silicone foam layer) and covering the battery pack lids, as well as selecting performant sealing materials (can also be silicone sealing foam) to close the pack.
Rapidly charging the battery raises the temperature owing to the faster electrical currents. This may amplify the effect of hot conditions on the battery.
Thermal Management Substances:
Batteries tend to heat up quickly at certain points throughout their operational cycle, such as when they are at full capacity or during the charging (or fast charging) process. Thermal management methods are being developed by engineers to maintain the battery safe and efficient. The selection of a suitable thermal management material is one of the most important parts of these systems.
These materials are designed to either restrict heat propagation through thermal insulation or, on the contrary, to force heat outside through a cooling system (often formed of cooling fluids): this is referred to as thermal conductivity.
On the market, numerous material technologies are accessible, the most important of which are silicones and polyurethanes. Understanding the nuances of these two technologies may be a headache for non-chemists engineers, given that one material might conceal many product families.
Silicone foams, for example, are effective insulators, yet silicone gap fillers are thermally conductive.
How to Increase the Efficiency of Electric Vehicles in Hot Weather
Your first priority is to protect the electric vehicle battery pack from hot weather conditions like Summer.
Here are some tips that can be applied to take care of your electric vehicle battery pack as well as increase the efficiency of the battery pack.
Place your Electric Car in a Shady location.
Parking your electric vehicle in shaded areas helps keep your battery cooler, allowing less electricity to be needed to cool the car. Parking garages, especially underground units, are excellent, but locating a large tree to park below can also help keep your electric car cool.
Keep charge minimum 20% and maximum 80%.
Whether you own an Electric Vehicle or just a cell phone, you’re surely aware that contemporary batteries charge the fastest from approximately 20% to roughly 80%. Above 80%, the battery requires more effort to charge, similar to packing a bag.
This effort creates heat, which causes the problems outlined above. This contradicts the intended purpose of increasing range. It will, however, keep the battery cooler, which will help your car run more efficiently for the miles you do have to traverse.
You may be able to use more of your car’s accessories if you free up a bit more power, which brings us to our following two ideas.
When feasible, use Slow Charger
Fast charging has emerged as a key selling element for many EVs. Manufacturers want your electric car to be your sole vehicle, however, this raises the issue of range for extended excursions. As a result, the faster the charge, the more desirable the vehicle.
Fast charging, on the other hand, creates more heat, and heat requires energy to disperse via the cooling mechanism. Slow charging is thus advised throughout the heat. You should prepare for this.
For example, instead of immediately charging the battery before leaving work, you may charge it overnight when you’re at home.