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Past, current and future trends in e-bike battery testing & safety

In 2012 a seasoned Dutch electronic design team started to design a battery analyzer, specifically for e-bikes and after extensive consultation of the e-bike industry. After extensive alpha & beta testing in 2013 by many e-bike professionals and many valuable suggestions, the final release –aimed at e-bike dealers- was introduced in February 2014 and in fall 2014 follow-up models for S-Pedelecs and higher.

Now, Battery Condition Test’s battery analyzers are widely in use for battery warranty and fitness-for-use analysis by manufacturers and dealers alike. Major system manufacturers such as BionX and TranzX use them for Quality Assurance, prototype and lifetime evaluation. Dealers judge the value of e-bikes offered for trade-in, give well founded replacement recommendations based on professional, objective test reports and can test whether batteries qualify for warranty (100% with BMS support).

This article explains the current market, philosophy, how it all started and what the future will bring.

Current market for e-bike battery testing

In the European dealer market Battery Condition Test is the market leader, but also the only vendor to offer a Terminal Converter Set that enables easy, universal connection to a wide variety of e-bike batteries without the need for custom cables. Dealers especially appreciate they can judge the value of to-be-traded-in e-bike batteries and can give sound recommendations -all without training-.

The combination of factory certified battery profiles and user friendliness enables manufacturers to involve dealers in the warranty fulfillment process. Several manufacturers recommend dealers to use Battery Condition Test’s battery analyzers, simply because it reduces their warranty cost.

Battery Condition Test Philosophy

Battery Condition Test believes that in order to be a valuable partner of the e-bike community, just supplying a product isn’t good enough. Identify and provide solutions for industry issues is the motto.

After the initial industry consultation we understood that battery quality, -warranty cost and –safety were the issues. To better and economically judge battery quality we included lifecycle testing (replaces expensive lifecycle-only testers). We offer manufacturers to involve dealers in warranty eligibility, opening the door to ‘no-risk’ electronic warranty fulfillment saving huge on logistics.

During Eurobike 2012. James Post, managing director and responsible for the strategic direction, was asked whether there could be a possibility to improve lithium battery safety. James picked up the challenge, discussed with many peers during several EV and battery technology conferences, where he was a speaker on battery testing. During the prestigious Battery Safety Conference of December 2013 he was presenter and led a forum discussion on “A Better BMS is key to better battery safety”.

Three months later Professor Michael Pecht of CALCE, a major test lab at the University of Maryland, visited James in Hong Kong and decided to cooperate in what is now the “Better BMS Group” or BBMS. Soon thereafter Alexander Kool joined in to add advanced electronic design know-how. At the 2013 Battery Safety Conference, James co-presented a concept solution. During a joint presentation at Eurobike 2014, Michael and James explained how to improve not only battery safety but also test-ability and reduce warranty cost by better monitoring.

Mid November 2014, BBMS invited major industry stakeholders to join the BBMS Group.

Courses

During major e-bike trade shows James provides free courses in cooperation with show organizers on battery theory, testing, (optimal) handling and warranty (evaluation); dealers widely lack knowledge. In 2015, BBMS will organize BMS courses for technical managers of e-bike (system) manufacturers.

How it started

Dutch high tech electronics company Engineering Spirit BV had designed and produced battery analyzers for service centers of Hitachi Europe. After that product was added to their website engineering-spirit.nl demand arose for battery analyzers for e-bikes. In the summer of 2012 Alexander Kool, Managing Director of Engineering Spirit BV entered into a cooperation with long-time (since 1975) project partner James Post, conceptual designer & (marketing) strategy specialist.

After analyzing the market and consultation visits to major e-bike (system) vendors the conclusions were that all existing battery testers in this category were (are…) too simple and are not “analyzers”:

  • Discharging was (is… with all other testers in this segment) done the “quick and easy” way by transforming the discharge energy 100% in heat (“programmable heater”), thus significantly reducing maximum power dissipation & reliability and short lifetime at frequent use.
  • Contrary to modern professional design strategies, the functionality was (is…) determined by the hardware, which means that any functionality beyond the designer’s idea is impossible.
  • Analyzers were (are…) difficult to operate and take too much time as starting up the charge/discharge/recharge cycle took (takes) manually changing cables 3 times.
Conceptual Design
  • Use the latest regenerative technology to reduce the heat dissipation to 10-15%: a factor 7-10 better. This enables larger discharge capacities in smaller enclosures at higher reliability and longer lifetime.
  • All functionality in software both for the firmware (inside the analyzer) and PC/laptop to ensure future insights and user wishes can be implemented easily and accessible for all (since day 1) users.
  • Fully automate the charge/discharge/recharge cycle to reduce analyzing cost and duration.
  • The novel concept of battery/motor profiles that can be provided by system or e-bike manufacturers or generic profiles for different battery/motor combinations. This way, a non-engineer does not need to know test parameters (and cannot change them), while operation is as easy as a cell phone.
Future Trends
  • More e-bike and –battery (system) manufacturers will take advantage of the free offer to support their BMS, as well as the free opportunity to evaluate their current BMS by competent specialists. Their major motivation will be to reduce warranty costs and dealers will be involved in fulfillment.
  • Battery designers will gradually adopt BBMS as it offers them improved battery safety during both operation (constant monitoring by the safety algorithms) and recycling by printing the safety record. Early discussions with industry stakeholders and major test institutes indicate acceptance.
  • A Charge Controller will allow consumers to improve battery lifetime by reducing the charge and discharge range, similar to electric vehicles. The BMS of the future will include charge controlling.
  • It is already EC law that e-bike lithium batteries may only be shipped without expensive, fireproof containers when the battery is “known safe” but the law does not specify a method. Discussions with normalization test institutes are ongoing to certify BBMS (or equivalents) as solutions. Safety reports can then be printed by any battery analyzer or BMS reader that supports (is free) BBMS.