Batteries in a Portable World 2^nd Ed.
       A Handbook on Rechargeable Batteries for Non-Engineers

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15.3 The Million Dollar Battery Problem

In today’s surging mobile phone market, many batteries are returned to mobile phone carriers before the ink on the invoice has dried. The most common consumer complaint is ‘less than expected’ runtime.

The reasons for this failure are multi-fold. The battery may not have been properly formatted at the factory. Perhaps the packs remained on the shelf too long or have been discharged too low. Incorrect customer preparation is also to blame. The true reason for such failure may never be known.

Dealers are not equipped to handle the influx of returned batteries. To fulfill the warranty obligations and satisfy the customer, the dealer hands out a new battery and sends the faulty pack to the manufacturer. Truckloads of ‘worthless’ batteries are transported, only to be stockpiled in warehouses for eventual testing or recycling at the manufacturer’s expense. The cost of exchange, time lost by retail staff, shipping, warehousing and eventual disposal amounts to a million dollar problem.

On a recent visit to Europe, a Cadex staff member learned that a large phone manufacturer had received 17 tons of failed handset batteries in one year alone. The batteries were stockpiled in large barrels for recycling. He also discovered that 15,000 NiMH batteries were returned to the manufacturer within weeks after the release of a new phone. When spot-checking the failed batteries with a Cadex 7000 Series battery analyzer, most packs appeared to be operational.

On another occasion, a total of 14,000 Li-ion batteries were returned to a North American mobile phone provider. Of these, only 700 (or 5 percent), were faulty. Of these, ten random batteries were sent to Cadex for further testing. The Cadex lab reported that each of these failed packs indeed had genuine faults.

A European service center sent 40 Li-ion polymer batteries to Cadex for evaluation. These packs had failed in the field and were returned to the service center by customers. When servicing the batteries on a Cadex 7000 Series battery analyzer, 37 units were found to be fully functional with capacities of above 80 percent and impedances below 180mW.

Phone manufacturers report that 80 to 90 percent of returned batteries have no faults or can easily be repaired with battery analyzing equipment. The remaining 10 to 20 percent, which do not easily recover with basic service, can often be restored with extended programs. Only a small percentage of batteries returned under warranty exhibit non-correctable faults.

Not all batteries and portable equipment under warranty fail due to manufacturer’s defects. A service manager for a major mobile phone manufacturer hinted that submersion into a cup of coffee or soft drink is a sizable contributor to equipment and battery failures. Apparently, the acids in the beverages manage to corrode the electrical conductors. Submersion into coffee occurs when the user mistakes the coffee cup for the phone cradle.

In an effort to salvage returned batteries, a leading mobile phone manufacturer segregates battery packs according to purchase date. Packs returned within the thirty-day warranty period are marked as type B. The batteries are then sent to a regional service center where they are serviced with battery analyzers. If the batteries are clean, (have no coffee residue) and regain a capacity of 80 percent or higher, the packs are relabeled and sold as a B class product. Over 90 percent of their returned batteries have been reclaimed with this program.

On the strength of this success, some battery-refurbishing houses have extended the service to include batteries of up to one year old. The service center experiences a 40 to 70 percent restoration yield in repairing these older batteries. The battery-refurbishing centers are said to make a profit. Equally important, such programs reduce the environmental impact of battery disposal.

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