how much to replace hybrid battery?

Hello, It is impossible to say. For a new, 2017 model, if you had to replace it in three years, the price will likely be in the 4-6000 dollar range. However, that would be a very short lifespan. In reality, it will probably last for around 10 years, and so many aftermarket and rebuilt options are already becoming available that I cannot see it costing near that much. For a good estimate, look at the cost of a new v. rebuilt battery for one of the 05-07 Accord hybrids, but even this will represent a higher cost.