http://blog.luxresearchinc.com/blog/2016/03/why-chinas-skyrocketing-plug-in-vehicle-sales-numbers-do-not-tell-the-full-story/

4. The battery pack size is much smaller in China than in other markets like the U.S.: In our analysis, we have found that in Q4 2015 the average pack size in plug-ins sold on the U.S. market was 53 kWh per vehicle, helped by the popularity of the Tesla Model S and new Model X. However, in China, plug-ins use much fewer batteries – on average, just 19 kWh per average plug-in sold. There is also the issue of which types of batteries are preferred: China’s developers continue to use large amounts of lithium iron phosphate (LFP) cathodes, whereas in the U.S. and Europe OEMs are moving towards newer nickel manganese cobalt (NMC) cathode chemistries. Therefore, although the China market looks alluring from a raw vehicle unit sales count, the preference for smaller battery packs and older cathode chemistries means that developers should judge their investment levels carefully.