The noun 日本队 (Rìběn duì) means "Japanese team" or "Team Japan." It follows the common pattern of country name + 队 (team) used in sports contexts. Similar formations include 中国队 (Chinese team) and 美国队 (American team).
日本队在这次比赛中获得了三枚金牌。
Rìběn duì zài zhè cì bǐsài zhōng huòdé le sān méi jīnpái.
The Japanese team won three gold medals in this competition.
日本队的表现超出了很多人的预期。
Rìběn duì de biǎoxiàn chāochū le hěn duō rén de yùqī.
The Japanese team's performance exceeded many people's expectations.
今晚中国队对阵日本队,你要看吗?
Jīnwǎn Zhōngguó duì duìzhèn Rìběn duì, nǐ yào kàn ma?
China is playing against Japan tonight—are you going to watch?