Battery swapping was quite common in the early months at ANA and JAL, almost routine, until runaway problems really began to appear.
Since the subsequent patches and improvements, the news blanket has been so heavy that I doubt such things would make it into the press. I have no idea whether or not batteries are being swapped out during routine checks, but my gut feeling is that such a culture would surely be encouraged, and any suspect batteries would be swiftly sent off for analysis in order to help refine the science.