if you’re low on HP and Fuel from the last two battles ( or three, I forgot XD ), then you might won’t survive to fight Elly, expecially with her "Aerods" attack.
I suggest use the attack level 1 or 2 combos as soon as you get them. Also, instead of the 30 fuel attack ( a bit risky because its often misses ), the 20 fuel attack will be more useful in this battle.
Still beaten? I give up 😮