A residence card is not considered a valid travel document to cross internal EU borders (Artical 21 Convention implementing the Schengen Agreement) . A residence card, togeather with a valid travel document (passport), shows you are legally in the Schengen Area.
A valid travel document is defined as:
- valid for at least 3 months after the date you intend to leave the EU country you are visiting
You should rid yourself of the notion that just because there are no regular border checks does not mean you can travel without required travel papers.
Spain has the strictest requirements in the EU: you must carry required documentation at all times (as apposed to others where you are required to only to have them).
Any check that shows that your passport has expired will lead to problems, since you don't even have a valid travel document.
Therefore allowing your passport to expire and then go to the country with the strictes rules is truly a very foolish thing to consider.
The Schengen acquis - Convention implementing the Schengen Agreement of 14 June 1985 between the Governments of the States of the Benelux Economic Union, the Federal Republic of Germany and the French Republic on the gradual abolition of checks at their common borders
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Article 21
- Aliens who hold valid residence permits issued by one of the Contracting Parties may, on the basis of that permit and a valid travel document, move freely for up to three months within the territories of the other Contracting Parties, provided that they fulfil the entry conditions referred to in Article 5(1)(a), (c) and (e) and are not on the national list of alerts of the Contracting Party concerned.
Passport and visa requirements
If you are a non-EU national wishing to visit or travel within the EU, you will need a passport:
- valid for at least 3 months after the date you intend to leave the EU country you are visiting,
- which was issued within the previous 10 years,
and possibly a visa.
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If you have a valid residence permit from one of those Schengen countries, it is equivalent to a visa.
This statement is based on Article 6 - Entry conditions for third-country nationals of the Schengen Border Code.
The Schengen Border Code does not specify anywhere that Article 6 (1)(a)(i) does not apply for residence permit holders visiting other Schengen Countries.
The German residence law AufenthG § 15 (2)(3) quotes Article 6 directly as a reason for Refusal of entry.
Sources:
- Convention implementing the Schengen Agreement - EUR-Lex - 42000A0922(02) - EN
- Travel documents for non-EU nationals – Your Europe - Your Europe
- AufenthG § 15 Zurückweisung
- AufenthG Section 15 Refusal of entry
- the english version states Article 5 instead of Article 6
- AufenthG Section 15 Refusal of entry