As we have seen in another article, electric vehicles (EVs) are growing in popularity all over the world. Countries like India stand to gain from the benefits EVs offer like lower air and noise pollution. Additionally, the per-km cost of driving EVs works out to be cheaper than petrol or diesel vehicles.
We have covered the importance of engine design and how multi-simulation software like Altair SimSoft helps. In this article, we will highlight the importance of battery simulation software in EVs.
There are four major types of electric vehicles available in the market today
- Battery Electric Vehicle (BEV)
- Hybrid Electric Vehicle (HEV)
- Plug-in Hybrid Electric Vehicle (PHEV)
- Fuel Cell Electric Vehicle (FCEV)
Irrespective of their type, the battery constitutes an important part of all types of EVs. The battery range in EVs is defined as the maximum distance that the vehicle can travel on a single charge of its battery. It is one of the most important determining factors in a customer’s decision to buy a particular model of EV. This makes sense as to-date there is no extensive network of charging stations for EV batteries. The problem is more critical in the rural and semi urban areas. The battery range of an EV depends on a variety of factors, including the capacity of the battery, the efficiency of the electric motor, the driving conditions (such as terrain, weather, and traffic), and the driving style of the driver. But the overarching factor that decides an EV battery’s performance is how well it is designed.
Types of EV Batteries
EVs use various types of batteries to power their electric motors, the most common being:
- Lithium-ion (Li-ion) batteries: These batteries are the most commonly used in EVs today due to their high energy density, long cycle life, and relatively low cost. They are made up of several individual cells connected in series and / or parallel to create a battery pack.
- Nickel-Metal Hydride (NiMH) batteries: NiMH batteries were once the most common battery type used in hybrid electric vehicles (HEVs) before the advent of Li-ion batteries. They have a lower energy density than Li-ion batteries but are still more energy-dense than traditional lead-acid batteries.
- Lead-Acid batteries: Lead-acid batteries have been used in EVs for many years and are still commonly used in smaller electric vehicles, such as golf carts and two wheelers. They are inexpensive but have a lower energy density than Li-ion and NiMH batteries and have a shorter cycle life.
- Solid-State batteries: Solid-state batteries are a newer type of battery technology that is still in development. They promise to have higher energy density, faster charging times, longer cycle life, and improved safety compared to Li-ion batteries.
- Zinc-Air batteries: Zinc-air batteries are another type of battery technology that is still in development. They have a higher energy density than Li-ion batteries and could potentially be cheaper and more environmental friendly since zinc is abundant and recyclable.
EV Battery Design Considerations
With so many types of batteries, there are several challenges in EV battery design. Here are some of the main challenges:
- Cost: The cost of batteries is still relatively high, which makes EVs more expensive than traditional gas-powered vehicles. This is because EV batteries use expensive materials such as lithium, cobalt, and nickel.
- Range: The range of an EV is limited by the capacity of its battery. While EV batteries have improved significantly in recent years, they still have a limited range compared to fossil fuel powered vehicles. This means that drivers need to plan their trips carefully and may need to recharge more frequently.
- Charging time: Recharging an EV battery takes much longer than filling up a petrol tank. While fast-charging stations can recharge an EV battery in about 30 minutes, it can take several hours to fully recharge a battery using a standard household outlet. And as mentioned earlier, there is no extensive network of charging stations yet in India as well as abroad. Battery lifespan: EV batteries have a limited lifespan. As their performance meteorites, they need to be replaced, which can be expensive.
- Safety: EV batteries contain large amounts of energy and can pose a safety risk if they are damaged or mishandled. Battery manufacturers need to design their batteries to be as safe as possible and to prevent fires or other accidents.
Battery Design Challenges
Keeping the above considerations in mind, there are several technical parameters that affect the design of EV batteries. Some of the most important design parameters include:
- Energy density: refers to the amount of energy that can be stored in a given volume or weight of battery. Higher energy density batteries can store more energy, which translates to longer range
- Power density: refers to the amount of power that can be delivered by a battery per unit of volume or weight. Higher power density means more power and acceleration.
- Battery chemistry: the chemistry of the battery cells determines their performance characteristics, including energy and power density, cycle life, and safety. Different chemistries have different trade-offs, and manufacturers use simulation software to optimization the design.
- Thermal management: Excessive heat can reduce battery life and safety. The design of good battery cooling systems is a critical aspect of batteries.
- Charging rate: Faster charging rates require more robust batteries and charging infrastructure.
- Cycle life: The number of charge-discharge cycles that a battery can undergo before its performance degrades is an important parameter for EV battery design. Higher cycle life batteries reduce the need for battery replacements over the lifetime of the vehicle.
EV Battery Simulation Software
Optimizing battery design for EVs for the above parameters can be done through the use of simulation software. It allows designers to create more efficient and effective batteries that meet the needs of EVs. Since there are many facets to designing of EV batteries, there are different simulation products that focus on a niche parameter. Altair for example offers several software tools that are useful for EV battery design. They include Flux™, OptiStruct™, HyperMesh™ and AcuSolve™. Flux models and analyzes the electromagnetic properties of batteries, OptiStruct analyzes the structural properties of battery components, HyperMesh creates finite element models and AcuSolve analyzes the thermal properties of batteries. Battery range, charging time and battery life are critical to the success of an EV, and manufacturers should do well to explore all the battery simulation tools that can assist them in this task.
