This is a summary from the panel discussion by the same title at the Future of Electrification 2023 conference. It was moderated by Conway Hui, Director of Sales Application Engineering and Customer Support at Delta-Q Technologies, and included Chris Botting. Manager, Research Engineering at Delta-Q Technologies, Luca Vezzadini, Applications Engineer, Zivan and Erik Stafl, President at Stafl Systems. Watch the full session here:
The panel discussion began with the topic of lithium ion batteries and the panelists agreeing that lithium ion batteries are here to stay for the foreseeable future. The reason for this is that lithium is the ideal ion for energy storage due to its lightweight and highly electro-negative properties. While there are different variants and flavors of lithium-ion batteries, advancements in the cathode and anode levels continue to extend the capabilities of the core technology.
There are some new technologies being developed, such as solid-state batteries, which use solid electrolytes instead of liquid ones, and IT management systems to manage the thermal aspects of the batteries. However, the panelists agreed that lithium-ion batteries will continue to evolve and refine over time, rather than be replaced by an entirely new type of battery. While there may be variations in the chemistry and materials used, lithium-ion batteries will likely continue to be the dominant type of battery in the next 10 years and beyond.
Stafl discussed the increasing trend towards using fully temperature-controlled packs in larger machines and in the automotive industry that is likely to translate to smaller packs and industrial market. Lithium-ion cells are becoming less expensive on a per energy storage basis, which means that there is a focus on reducing the cost of the other ancillary pack components, including thermal management, mechanical structure, and battery management systems.
Thermal management is critical for the performance and safety of the pack, as a pack is only as good as its weakest cell group. There are new and innovative technologies being developed each year to improve thermal management, including efficient liquid cooling channels and immersion cooling. Overall, the panelists agree with the expectation of a continued investment and focus on thermal management of lithium-ion packs across all applications in the coming years.
The conversation then turned to heat management in lithium packs and Vezzadini highlighted the two main methods of cooling a battery system: air or liquid cooling. However, a new method involves using a phase change material to store and release heat, which can reduce the temperature of the battery. Botting added that thermal management depends on the application, and managing temperature is crucial, as increased temperature shortens the battery life. Passive cooling methods such as phase change material can help extend the life of the cells and help them stay better balanced, but adds cost, size, and weight. Liquid cooling is the most effective method of cooling and is suitable for larger machines with high duty cycles and expectation of high power.
In smaller machines, fan cooling is still reasonable, but active cooling of the battery should be considered for a one to two-hour charge rate. The panelists emphasized that understanding thermal management is critical as it affects battery life and performance. The choice of cooling method will depend on the application and its usage profile, as each method has its advantages and disadvantages, such as cost, weight, and complexity of the system.
The next topic of discussion was the importance of heating mechanisms for lithium-ion batteries in cold temperatures, as charging at low temperatures can damage the cells due to lithium plating. Stafl suggests using film or fluid heaters to warm the batteries and emphasized the importance of considering low temperature operation during the design and operational phases, especially for vehicles used in very cold temperatures.
Another point of discussion was solid state batteries and fast charging. The panelists discussed the different types of solid state batteries and their potential advantages over traditional lithium ion batteries. They also discussed the practical limitations of fast charging, including the availability of charging infrastructure and the cost of electricity. The panelists noted that while there are practical limits to how fast batteries can be charged, there are no theoretical limits, and improvements in battery technology are made incrementally over time. A final point of discussion on this topic was that data shows that fast charging does not necessarily lead to significant battery degradation over time.
The discussion then turned to the topic of wireless charging and battery recycling. Botting discussed the feasibility and practicality of wireless charging, highlighting its limitations and potential applications. He also touched upon battery recycling, emphasizing its importance in promoting sustainability. The panelists agreed that wireless charging may not suitable for some applications and that conductive charging remains the dominant technology. They also stress the need for standardization and improved efficiency in wireless charging.
The discussion moved on to the topic of battery recycling and the need to close the loop on the materials used in lithium-ion batteries as society moves towards electrification. The panelists covered different methods of recycling, including Redwood Materials' innovative grinding solution that separates elemental compounds from a fully completed pack. The reuse of batteries was also discussed, with the suggestion that batteries could be given a second life in less demanding applications before being recycled. The economic incentives and policy implications of battery recycling were also touched upon, with the need for built-in fees and polluter pays policies. The panelists emphasized the importance of designing batteries and chargers with sustainable materials to reduce the need for recycling in the first place.
The final topic was energy efficiency in the context of limited resources and increasing environmental concerns. Vezzadini discussed the importance of efficiency in improving battery life and reducing energy consumption, as well as the environmental benefits of renewable energy. The panelists also touched on the regulatory aspect of energy efficiency, particularly in North America. While there are diminishing returns in maximizing efficiency, there is movement towards tightening regulations and improving energy efficiency standards.
Stafl also added the importance of energy efficiency in the design of battery systems. He noted that phantom drop, or the energy consumed when a device is in sleep or shutdown mode, can have a significant impact on overall efficiency. He emphasized the need to design battery management systems that minimize phantom drop and recommends seeking guidance in this area.