Accelerating Cost Reduction and Longer Life for EV Batteries by Enabling Thin, Flat, Robust Battery Interconnects
If the initial manufacturing cost of batteries can be reduced and battery lifecycles extended, it will help to increase the growth in market share for electric vehicles, which ultimately will have a significant impact on reducing greenhouse gas emissions and improving air quality.
This article provides a deeper dive into the importance of Battery Interconnect System technologies that are helping reduce EV battery costs by simplifying design and assembly while at the same time extending battery lifecycles by improving current flow and minimizing hot spots within EV batteries.
Why are Battery Interconnects Important?
Figure 1 - Battery interconnects are typically customized to customer requirements and can support high currents and high voltages.
Battery interconnects typically consist of a set of current collectors, which are most often made of copper or aluminum, and are bonded to the electrodes of the battery cells. They provide a low-resistance pathway for the flow of electrical current from the battery cells to the external circuit.
Current collectors also help to distribute the electrical current uniformly across the battery cells, thereby improving the overall performance and longevity of the battery pack.
Figure 2 - Current collectors are designed flat and thin for better heat dissipation and to fit in a flat battery pack.
In addition, the use of battery interconnects can help to simplify the manufacturing process of battery packs by reducing the number of interconnects required between the battery cells and the external circuit. This can help to reduce the overall cost of manufacturing battery packs and make them more affordable for consumers.
Key Challenges for Battery Interconnect Optimization
Figure 3 - The challenge over increasing energy storage efficiency remains as the need for bigger battery packs while retaining or reducing battery size and weight continues.
Accommodating Larger Battery Modules with More Individual Cells
Reducing Weight of Battery Packs
Figure 4 - Homogeneous temperature and current density distribution improves the aging behavior of Li-Ion battery cells.
Avoiding Hot Spots
Using a battery management system (BMS) can help by monitoring temperatures and adjusting the charging and discharging rates or the BMS can issue alarms and shut down the battery if necessary. Adding insulation or cooling can help too but increases both cost and complexity. Ultimately, the best way to deal with hot spots and lack of cell balancing is to design current collector assemblies for optimal current distribution throughout the battery.
How Cell-PLX™ with U-Turn Technology Optimizes Battery Interconnect Systems
Figure 5 - The current collector can be as long as 1600mm and as thin as 0.2mm, with options for cold or hot lamination.
Using customizable attachment processes to support specific application requirements, Cell-PLX™ battery interconnect systems are designed to provide a permanent, reliable, robust, and safe solution for current collectors to interconnect EV battery cells and provide electric power to the vehicle.
During the battery interconnect assembly process, the current collector with a dielectric layer, data collection media which consists of the flex printed circuit (FPC), battery cell holder and individual cells are all brought together in a highly efficient and robust manner that supports high-volume manufacturing and can be adapted for virtually any battery pack size, power requirements and configuration.
Figure 6 - Aluminum/copper current collector transfers current from the prismatic cells to the rest of the battery pack.
Flatter and Thinner Current Collectors
Minimizing Hot Spots with U-Turn
Figure 7 - With U-Turn, the energy flow is markedly better organized as it moves from the positive to the negative terminal via a single conductor layer.
Here again, Interplex’s precision, high-volume manufacturing methods and quality control measures ensure each Cell-PLX™’s current collector has a consistent thickness, even for very large battery interconnects, which helps achieve this evenly distributed power spread with U-Turn across the whole battery interconnect system.
Figure 8 - Interplex patented U-Turn technology helps mitigate hot spots in current collector designs.
- Provides even spread of current throughout the battery.
- Eliminates current bottlenecks that cause temperature spikes.
- Distributes uniform current density across the battery.
- Elimination of hot spots prevents degradation of battery life.
Keen to understand how our Cell-PLX™ core technology can be applied to your battery applications?
Figure 9 - Cell-PLX™ battery interconnect system in cylindrical and prismatic cell form factors.
- Lowering the cost of EV batteries will make EVs more affordable and accessible to a wider range of consumers, accelerating the transition to a more sustainable and low-carbon transportation system.
- Longer-lasting batteries can help to improve the performance and range of EVs, making them more competitive with traditional gasoline-powered vehicles and increasing consumer confidence in EVs.
- As the adoption of EVs increases, the environmental impact of transportation will decrease, reducing greenhouse gas emissions, air pollution, and reliance on fossil fuels.
- The same battery technology used in EVs can also be used for energy storage systems, such as grid-scale batteries or residential energy storage systems. If the cost of batteries can be reduced, it could help to accelerate the deployment of energy storage systems, which are essential for integrating more renewable energy sources into the grid and improving grid stability.
- The high cost of EV batteries is often cited as a major factor contributing to the low profitability of EV manufacturers. If the cost of batteries can be reduced, it could help to increase the profit margins of EV manufacturers, which would in turn lead to more investment in research and development, and ultimately lead to more affordable and better-performing EVs.
- Enhanced battery designs can also lead to improvements in battery recycling, as a larger portion of batteries can be reused or repurposed, reducing waste and promoting a circular economy.