Designing better electric vehicle batteries
In recent decades, leading automobile manufacturers, such as General Motors, Ford Motor, and Volkswagen have been developing “green”, emission-free electric vehicles in order to transition from internal combustion cars. Much of the research into electric vehicles is focused on designing better electric vehicle batteries.
Although at present, the electric vehicle battery of choice is lithium-ion batteries, there is the need for improvements in EV battery design so that the current crop of batteries is efficient to assemble, more stable to prevent the occurrence of fires and explosions, provides a greater driving range, and gets charged fully at a faster time.
What are EV batteries?
EV batteries are considered the “heart” of an electric vehicle, delivering electric power in order for an electric vehicle and its various systems to run.
To those who are unfamiliar with the electric vehicle battery, they erroneously believe that this important part of the EV is only a single battery cell. In truth, EV batteries are made up of a number of individual EV battery cells. EV battery manufacturing allows for the aggregation of these cells into battery packs, but more on this in the section below.
What are EV batteries made of?
As we have mentioned above, an electric vehicle battery consists of a number of cells which are combined together in an EV battery pack. So, what are EV batteries made of?
Let’s first take a look at a single EV battery cell in order to know what they are made of. Each individual cell consists of six major EV battery components. There are two electrodes in a single cell – the negative electrode or anode is made of graphite while the positive electrode or cathode is made of aluminum, nickel, cobalt, manganese, iron, and lithium.
These two electrodes, called current collectors, are wrapped in thin foils of aluminum (for the anode) and copper (for the cathode). The electrodes are then kept apart from each other to prevent short circuits by a separator made from polyolefin, a microporous polymer. This entire setup is immersed in a liquid electrolyte of lithium hexafluorophosphate. Finally, these components are placed in a casing made out of aluminum and steel.
There are three components in the design hierarchy of EV batteries. The most basic unit in the hierarchy is the EV battery cell, which we have discussed above. Depending on the power requirements of an electric vehicle, a certain number of EV battery cells are combined to form an EV battery module. Last but not least, the modules are combined to form a single battery pack.
In the manufacturing of EV batteries, certain components may be added to improve the overall performance of the battery. Good examples of these components of next generation EV batteries are the BusMate® pluggable power connectors and the Cell-PLX™ battery interconnect system.
Designing Interplex BusMate®: What does it consist of?
Before we talk about the Interplex BusMate®, let us first briefly discuss busbars. The humble busbar is a conductor, allowing for the flow of current through an electric vehicle’s sub-systems.
With the EV battery considered as the heaviest part of an EV, there is the need to make the battery smaller and lighter but still capable of providing the right power requirements. Suffice to say, the busbar should also be adapted to meet the new battery design in terms of using smaller footprint busbar interconnects to the printed circuit boards (PCBs) and improved flexibility in the configuration and production of these same busbars.
The BusMate® Power Busbar Connector designed by Interplex allows for a compact, solderless, and economical interface for the connection of busbars to EV battery cells and EV battery modules. The Busmate® is made out of copper, brass, or aluminum depending on the EV battery performance specifications.
The main features of the Interplex BusMate® are:
- Compact size of 8.4 x 6.0 x 9.9 mm
- Superb ampacity-to-size ratio
- Capable of accommodating large assembly tolerances: ±0.8mm mating blade offset, ±16 degrees of twist, and a range of insertion depth
- Customization and scalability for higher currents
- High temperature construction: 150o C
Designing Interplex BusMate®: What does it consist of?
The Cell-PLX™ from Interplex is a customizable EV battery interconnect system. Its thin, lightweight design allows it to fit into the tightest spaces and light weight constraints while maintaining both mechanical sturdiness and electrical robustness so that it can withstand various stressors both in and outside of the electric vehicle.
Among the key features of the Cell-PLX™ Interconnect system are:
- Customized single or multi-layer current collector designs
- Supportive of various current densities and cell array configurations
- Tight-tolerance current collectors
- Attachment options: Laser weld or wire bond
- Robust packaging formats for environments with high temperature and high vibration
- Multiple module-to-module connection options
- Seamless integration of both active and passive components for safety and battery cell monitoring
- Quick time-to-market; vertically integrated in-house production capabilities
Designing Interplex BusMate®: What does it consist of?
In designing an EV battery, an important factor that needs to be considered is sustainability. A major concern is the use of material components that are readily obtainable from various sources in the environment. For example, researchers are presently developing batteries that are cobalt-free, especially since cobalt can only be obtained from the Democratic Republic of Congo which significantly increases the cost of batteries.
Sustainable EV batteries depend on being able to use materials and components from old batteries and being able to recycle them into new batteries. This can be seen in recycling plants wherein they get aluminum, nickel, lithium, and other metals from old batteries for new ones.
Manufacturing EV batteries also means developing new technologies to allow for better performance, efficiency, and safety at smaller, more compact sizes, and at the same time, utilizing materials and components that are, again, easily obtainable and improve design flexibility. Good examples of such technologies include Interplex’s Cell-PLX™.
Future EV battery technology is coming sooner than people think, with researchers predicting new technologies, such as solid-state batteries, fast-charging batteries, and more to be coming from today to the year 2030.
