Velocity of money might be an element, but it's controversial. There are different opinions on it between neo-classics (that consider it constant or with small variations) and keynesians.
It's also necessary to take in account the difference between M1 (money created directly by the central bank) and M3 (global money assets, including money created by commercial banks).
In a credit crunch, with the money created by banks in decline, it's possible to increase hugely M1 without increasing M3. Therefore, no inflation happens.