This is a very interesting question indeed. Like so many parts of our legal system, there are two lines of reason supporting opposing conclusions for this question. By the written law (statute) the answer seems clear – there is no exception. By case law (precedent), we see at least some support in the courts for an exception to patent infringement based upon experimental use. This isn't a 50-50 proposition. I think the side of 'no fair use exception in patent cases' has a distinct advantage. Of course, one can never be certain what results a jury will finally produce in any particular case. Good luck.
In effect, the code reads: "Whoever makes, uses or sells a patented invention, therefor infringes the patent". Rarely do we have it so clear, simple and brief. But there it is. The code does not mention any exception for experimentation or otherwise with regard to patent infringement. One infringes a patent even when non-commercial use is privately executed in a dark laboratory without observers. One cannot use a patented invention – without infringing.
But the full story is not found in the patent statute, rather one must also consider the cases on point which have been decided by the courts. Because the patent system depends upon those later coming inventors who arrive to improve patented ideas, there must be some allowance for those new inventors to experiment with the art. At least that is how the theory begins. One might consider a useful writing on point from the Journal of Law and Technology to learn more details of this type of patent infringement defense.
This is a complicated approach to patent infringement defense. You will need to have a very serious discussion with your patent attorney before relying upon this to protect you from patnet infringement actions. Please advanced legal help if you wish to learn more about 'patent fair use'.