[Kalobbis]

The European team actually only has one more captains pick than the US. They chose the top 5 from the LET and then the top 4 from the LPGA who don't play on the LET. The 3 picks still left are then for captains picks. This way they aren't missing out on a top European player who only plays on the LPGA.
Here is a description of how points are calculated for both teams:

U.S. Team
For the 12-person squad, 10 players qualify for the U.S. Team by earning points for wins and top-20 finishes over a two-year
qualifying period, with two players selected by the captain.
Qualifying points for the U.S. Team are awarded weekly to the top-20 finishers and ties at official LPGA events. Only
U.S.-born LPGA Tour players are eligible for selection for the U.S. Solheim Cup Team.
Point values for Solheim Cup points are:
non-Solheim Cup years – 40 points for first, 20 for second, 19 for third, 18 for fourth, 17 for fifth, 16 for sixth, 15 for seventh, 14 for eighth, 13 for ninth, 12 for 10th, 11 for 11th, 10 for 12th, nine for 13th, eight for 14th, seven for 15th, six for 16th, five for 17th, four for 18th, three for 19th and 2 points for 20th place;
Solheim Cup years – 60 points for first, 30 for second, 28.5 for third, 27 for fourth, 25.5 for fifth, 24 for sixth, 22.5 for seventh, 21 for eighth, 19.5 for ninth, 18 for 10th, 16.5 for 11th, 15 for 12th, 13.5 for 13th, 12 for 14th, 10.5 for 15th, 9 for 16th, 7.5 for 17th, 6 for 18th, 4.5 for 19th and 3 for 20th.
The points listed above are doubled at the four major championships every year.

European Team
The European Solheim Cup Team is selected by taking the top five players from the LET Solheim Cup standings, followed by the top four European LET members on the Rolex Women’s World Rankings at the agreed cut off date who are not already qualified via The Solheim Cup standings, and three captain’s selections. Qualifying points for the European Team are awarded weekly to the top-10 finishers at official LET events.
Point values for The Solheim Cup are:
non-Solheim Cup years – 20 points for first, 12 for second, 9 for third and descending to 2 points for 10th place;
Solheim Cup years – 40 points for first, 24 for second, 18 for third, 16 for fourth, 14 for fifth, 12 for sixth, 10 for seventh, 8 for eighth, 6 for ninth and 4 for 10th.
Points are doubled for the Weetabix Women’s British Open and the Evian Masters.
In addition, any LET member who finishes in the top 10 in the U.S. Women’s Open, Kraft Nabisco Championship and the McDonald’s LPGA
Championship Presented by Coca-Cola on the LPGA schedule will receive the standard distribution for that year.
Also, any LET tournament with a prize fund of £500,000 or above will receive an additional weighting of 1-1/2 times the standard
distribution in each year.