A few times. Spoiler When they use their Matrix plot powers, activated by the phrase like "Autobots Unite!" and then get all glowy, that's the power. It's not hard light extra armor like the figures, but the whole character glowy super powers thing. It's the shows way of implementing the "Battle Call" feature that those soon to come out super-expensive voice activated figures are featuring. Hence it being used so often in the last half of the series, such as the Thunderhowl episode where Bumblebee uses it twice, each time saying the catch phrase before getting all glowy and able to solve the plot and when it's introduced, the limitation is that it has to be said out loud to activate. That's the shift that we've seen a bunch of times in various media and toys where characters can shift between a normal mode and a combat mode, something that's been seen a lot and even some toys do, like Cybertron Optimus Prime. Energon Armor and the Battle Call figures are emulating a different plot device as seen in the show Spoiler where with 2 Matrix of Leaderships, Optimus' normal one and Megatrons stolen one, combined to give them super plot breaking powers as needed.