Module and Battery Pack Manufacturing

Deciphering Stakeholder Strategies in Electric Vehicle Battery Recycling: Insights from a Tripartite Evolutionary Game and System Dynamics

There is no perfect disposable battery--one that will sit on the shelf for 20 years, then continually provide unlimited current, at a completely constant voltage until exhausted, without producing heat. There is no perfect rechargeable battery--one with all of the above characteristics and will also withstand an infinite overcharge while providing an equally infinite cycle life. There are only compromises. Every battery selection is a compromise between the ideally required characteristics, the advantages, and the limitations of each battery type. General selection of a battery type to power a medical device is largely outside the purview of the biomed. Initially, these are engineering decisions made at the time of medical equipment design and are intended to be followed in perpetuity. However, since newer cell types evolve and the manufacturer's literature is fixed at the time of printing, some intelligent substitutions may be made as long as the biomed understands the characteristics of both the recommended cell and the replacement cell. For example, when the manufacturer recommends alkaline, it is usually because of the almost constant voltage it produces under the devices' design load. Over time, other battery types may be developed that will meet the intent of the manufacturer, at a lower cost, providing longer operational life, at a lower environmental cost, or with a combination of these advantages. In the Obstetrical Doppler cited at the beginning of this article, the user had put in carbon-zinc cells, and the biomed had unknowingly replaced them with carbonzinc cells. If the alkaline cells recommended by the manufacturer had been used, there would have been the proper output voltage at the battery terminals when the [table: see text] cells were at their half-life. Instead, the device refused to operate since the battery voltage was below presumed design voltage. While battery-type substitutions may be easily and relatively successfully made in disposable applications (for example, zinc-air for alkaline--if it is cost-effective), this is absolutely forbidden for secondary cells. Because of the differing cell voltages, charge characteristics and overcharge tolerance between different types of secondary cells, substituting a nickel-cadmium battery pack for the more expensive lithium-ion pack (if it is physically able to fit into the battery compartment), might appear to save money (e.g. $50 vs. $100) but it would be very ill advised. Since the cell characteristics are very different, it would be downright fatal to anyone within the 'kill radius' when the pack explodes. Those outside the kill radius would receive chemical burns from the electrolyte. Substitutions of secondary cell battery packs are generally not a good idea for biomeds to engage in. These are engineering decisions best left to either aftermarket battery pack manufacturers or the medical device manufacturer as a design engineering change.

European and global energy policies are based on a competitive, sustainable and secure energy system in the coming years, promoting Renewable Energy Sources as a priority measure for long term sustainability of the energy sector. The lithium-ion battery value chain for E-mobility comprises a wide spectrum, starting from raw materials production, cell component manufacturing, cell manufacturing, battery pack manufacturing, electric vehicle integration and recycling. The extraction and exploitation of the most common raw materials generally comes from resource-rich countries outside the EU. The process of extracting raw materials causes an environmental footprint through water pollution and release of GHG emissions, producing half of the GHGs from the battery production segment. The EU could have a head start if strong and concerted research efforts are initiated now, both in academic research and pre-industrial development, so that know-how and intellectual property is generated early, serving as a basis for industrial production in the EU and market penetration worldwide.

Large battery systems like those in plug-in hybrid or pure electric vehicles contain strings of series-connected cells. Cell voltage imbalances within strings decrease useful string capacity and increase cell ageing. Balancing systems are often employed to alleviate imbalances but optimal design and sizing requires prediction of expected imbalance. This paper presents a methodology for simulating voltage imbalances caused by temperature-dependent reversible self-discharge processes in cells. Simulation results for a three-cell string with a 4°C operating cell temperature difference over 30 days show a maximum cell voltage divergence of less than 1mV. The same simulation with a malfunction-typical operating temperature difference of 20°C leads to a maximum voltage divergence of over 5mV. The results and underlying methodology are of value for battery pack manufacturers and designers of balancing systems.

A comprehensive analysis and optimization process for an integrated liquid cooling plate for a prismatic lithium-ion battery module