During the past several months, you may have read a number of horror stories about exploding batteries in laptops and cell phones. One such story is interesting; two stories unusual. But when I read three stories, all in reputable news outlets, well, that's a trend. I spoke with a few experts in the field of electrochemistry who told me the danger is real. When lithium-ion batteries replaced nickel metal hydride, researchers increased the energy density (the amount of power they could pack into the space), eliminated the memory effect, and made batteries lighter. But lithium ion in most cases uses cobalt oxide, which has a tendency to undergo "thermal runaway," explains Joe Lamoreux, vice president of research and development at Valence Technology. "When you heat this material up, it [can] reach an onset temperature that begins to self-heat and progresses into fire and explosion." Because Valence claims to offer a safer alternative, I also spoke with Atakan Ozbek, director of energy research at Allied Business Intelligence, an independent technology research think tank, and to Sandrine Colson-Inam, general manager at Cell Expert North America, another independent technology research company. Ozbek and Colson-Inam confirmed what Lamoreux told me. Both also agree that Valence's phosphate technology, registered as Saphion Technology, is definitely safer. Explosions and fire happen "rarely" but as Lamoreux said this problem is a "tiger in a cage" just because of the sheer number of batteries out there. Battery problems that result in fire, lots of smoke, and explosions can be caused by a short circuit, excessive heat, overcharging, or abuse. Ozbek advises users to replace lithium-ion batteries every two to three years. Two years is the safest time period, as constant recharging weakens the battery. Colson-Inam advises users not to leave a laptop or cell phone in the trunk of a car where the temperature can easily go above 140-degrees Fahrenheit, the point at which a thermal runaway can start. Valence has come up with a new active material for lithium-ion batteries based on phosphates rather than oxides. These batteries behave like the traditional lithium-ion version but don't have a thermal runaway characteristic. Currently, Valence is shipping outboard devices — N-Charge, weighing just under three pounds — as backup batteries to notebooks. They also sell a 60-pound version, K-Charge, to the telecommunications industry as backup for big switches. The next generation from Valence will be small enough to use as a direct replacement for your current laptop battery and will be available next year. Long-term fuel cells that convert hydrogen and oxygen to electricity — don't ask me how — are a promising alternative. But fuel cells, according to the experts, cannot handle peak loads, not even the peak load generated in a cell phone. Therefore, the alternative is a fuel cell with battery backup to handle the peaks. The awful truth is that improvements in battery technology will be played out during the next five years or so. When battery technology can be taken no further, you will be getting maybe 15 percent to 20 percent more energy than you do now from your battery. Intel and Texas Instruments, among others, are probably our best hope for innovation, as they continue to spend millions of dollars on power-saving technologies to squeeze more life out of the same old battery.