What Technicians and Service Managers Will Need to Know About Advanced Technology Vehicle Lithium Battery Technology
If you are a technician that is or will be working on advanced technology vehicles (i.e., hybrid, plug-in hybrid, extended range electric, or battery electric vehicles) Lithium battery technology may be something that you need to devote some additional attention. Service managers should also become comfortable with knowing the higher level aspects of vehicle Lithium systems technology to make it easier in conversing and recommending servicing options with the vehicle owner.
As the advanced technology systems continue to penetrate the market in higher volumes, the Lithium family of battery products becomes the choice of manufacturers that have entered the market in the past 6 years, due to its superior energy storage capability. Lithium products are manufactured with two basic formats – cylindrical and pouch. The cylindrical battery (typically an 18650 cell) is slightly larger than a AA battery and the pouch style cell can be manufactured in many different size configurations, dependent upon application. Unlike the current Nickel Metal Hydride (NIMH) that dominates the advanced technology market, Lithium technology has numerous chemistry and family categories. Each of these categories offer varied capacity and power characteristics. The primary families utilized in the automotive or medium/heavy duty market as of today are Lithium Cobalt Oxide, Lithium Manganese Oxide, Lithium Manganese Cobalt Oxide, Lithium Nickel Manganese Cobalt, Lithium Nickel Cobalt Aluminum, Lithium Iron Phosphate, and Lithium Nickel Cobalt Aluminum .
Each of these Lithium family chemistries can have very different delivery of its capacity and power. The electrolytes are/can be significantly different, although each uses Lithium Salt as a basic element. Each may have different additives in the electrolyte that mitigate aging, reduce the possibility of a thermal event (fires) with fire retardants, and permit enhanced performance, etc.
With six basic Lithium chemistries currently used in the market, it is essential that technicians understand the differences between the technologies and how each will react when testing the vehicle and how this relates to any associated diagnostic trouble codes and testing procedures. When working with the Lithium families of battery chemistries and performing testing (such as) Stress Testing, battery pack rebuilding, or battery systems testing it is critical that technician’s know which Lithium technology that is being used in the vehicle and the associated voltage level. For example, when working with the Lithium Manganese battery family, the associated diagnostics and any Stress Testing would result in data that (when viewed) is different when compared to a Lithium Iron Phosphate battery chemistry. The difference between these two chemistry examples is, the Lithium Manganese families have a very linear discharge voltage data when compared to Lithium Iron Phosphate chemistry that has nearly flat discharge voltage data. This means battery capacity may or may not be easily interpreted by using Scan Tool data unless a technician or service manager is aware of the differences between the Lithium families. Therefore, knowing how specific battery chemistries behave is critical in knowing how to interpret Scan Tool or off-board discharging equipment data.
The bottom line to all of the differences in Lithium chemistries is for the technician to know what to expect with viewing Scan Tool or off-board equipment data and how to interpret this data when testing the battery system, whether the battery pack is installed in a vehicle or it is on the bench.
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