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October, 2019


The Future of Electric Vehicle (EV) Battery Testing


By David Sigillo, Vice President, Seica, Inc. W


ith the expansion of electric vehicles around the globe, there is a growing interest in


the entire battery lifecycle, from chemistries and manufacturing to recycling. One needs only to log into any social media portal to find adver- tisements for not only electric cars and buses, but also electronic drones capable of carrying packages and even people. Aircraft manufacturers have


also been prototyping experimental aircraft that run entirely on battery power, as they await the next techno- logical leap in long-duration battery power life. With the increased focus on and


need for batteries, it is up to the OEMs to determine the best solution for their needs. For example, lithi- um-cobalt-oxide batteries are most commonly used for the consumer market. However, these have been judged unsuitable for automotive and transportation applications due to safety concerns. The most commonly used bat-


tery chemistries in the transporta- tion market are: lithium-nickel- cobalt-aluminum (NCA); lithium- nickel-manganese-cobalt


(NMC);


lithium-manganese spinel (LMO); lithium-titanium (LTO); and lithium- iron-phosphate (LFP). OEMs must weigh the tradeoffs of the six key components for battery selection in any given application —specific ener- gy, specific power, lifespan, perform- ance, cost, and safety. Most OEMs have decided to


buy. They purchase batteries from known producers. On the other hand, some larger firms have partnered with battery manufacturers, and as a result, have played a role in the glob- alization of battery production. With this globalization, a key


component has emerged, which at times, takes a backseat to the topics of chemistries and long life. That is production, and more specifically, battery testing.


Battery Production and Testing The production and testing of


batteries usually can be accom-


Seica’s Pilot BT battery test system can test nearly 2,400 battery cells per minute.


actually design and develop special- ized capital equipment themselves. Ten or more years ago, you could walk a production floor and see cus- tom-designed solutions along with integrated test and inspection work cells.


These work cells were typically


rudimentary at best, but they existed at a time when the market was still in its infancy, and they could keep up with production demands. The prob- lem with these highly customized solutions was that they were general- ly slow, testing only a few cells at a time using older mechanical technol- ogy, such as stepper motors. From a software standpoint, they lacked the sophistication to manage data, and they simply could not easily generate test programs for a variety of differ- ent battery cells or battery pack con- figurations, which are much more common today.


cal materials, or “energy” stored in the battery, but to verify the manu- facturing process — typically meas- uring and testing the connection of the cells in the battery pack to the particular positive or negative termi- nal plate. These connections are crit- ical to the lifespan of the pack and could have thermal implications caused by unbalanced energy. Battery manufacturers or OEMs pro- ducing or assembling the batteries need to ensure the reliability of the connection of the individual cells to the terminal plates. There are three crucial ele-


ments to consider when choosing a solution for battery production test: test speed, configurability and relia- bility. As the custom-designed test and inspection work cells used ini- tially have become inadequate to support the growth in volumes and the rapidly evolving technology,


plished in two ways. First, the bat- tery OEM forms a partnership with an integrator that has mechanical assembly experience; or second, they


Since the materials and chem -


istries generally remain constant for the life of a particular battery, the requirement is not to test the physi-


manufacturers have had to look for other test solutions which address all three.


Flying probe test was perhaps


the first standard automated solu- tion adopted by battery manufactur- ers, and these systems are now being widely used to measure the electrical connections in battery packs. Origin - ally used in an “adapted” version to verify electromechanical connections, as opposed to measuring component values and shorts or opens on a cir- cuit card assembly, at least one ven- dor has chosen the more innovative approach of developing a new solu- tion, which addresses current and future battery test requirements in terms of speed, configurability and reliability.


Three Critical Elements High throughput is the first


consideration. The new hardware architecture of the Seica Pilot BT, in the maximum configuration of four flying heads, is able to perform paral- lel, very precise Kelvin tests of 16 cells at once. The machine achieves production rates of nearly 2,400 bat- tery cells per minute, more than dou- ble what was previously available. The second crucial element, con-


figurability — the ability to test many different types of batteries — is paramount, because not all battery cells are created alike. This means that the fixed position probe configu- ration of the previous flying probe testers posed some limitations in terms of production test flexibility. The Seica solution overcomes


this limitation with “flying connec- tors,” that can be arranged from 2 to 16 channels in either an x- or y-axis orientation. If a customer is testing a certain battery configuration on first shift and then needs to run a differ- ent battery on second shift, they sim- ply change out the flying connectors for the alternate battery configura- tion. Another important factor is the size variability of battery packs, so the manufacturer needs to have the possibility to change the setup of the tester to accommodate products of


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