"Although" means "regardless of that fact". It introduces something that will happen despite something else.
Although it was raining, we played a full round of golf.
"Even if" is similar, in that it talks about something that will happen despite something else, the word "if" introduces a condition. This will affect the meaning of the verb tenses. For example, if we substitute this for although in my sentence:
Even if it was raining, we played a full round of golf.
the sentence no longer talks about a single past event. Now, it talks about a past habit because it becomes a zero conditional (same tense in the "if" clause and the result clause.
The conditional nature of "even if" makes it difficult to substitute for "although". "Although" deals with actual events. "Even if" deals with unreal, hypothetical, or future events.
Another phrase "even though" is closer in use to "although".