Does your introduction need to... introduce your topic and research question? Yes, clearly. However, it's worth going farther, as well. You are partly judged on your choice of topic and whether it is A) worthy of study and B) appropriate for a 4000-word research paper. 

What you do in your introduction can go a long way towards helping with A. Your introduction can also help you demonstrate relevant subject-specific knowledge that informed your choice of topic, familiarity with the methodology of your subject and the requirements or your topic, and establish the importance of your chosen EE topic. Let's take each of those things separately...

It's highly unlikely that you came into your EE topic because you knew absolutely nothing (though if you did choose a subject or topic you knew nothing about, congratulations for playing on "hard mode" I guess.)

The introduction section is a place for you to set out any necessary background information before you dive into the meat of your investigation. YOU are the researcher and writer and YOU get to determine what goes in here. Show your passion for the subject, show what you know! Use this to set up the investigation that follows. 

Past MDID students' (who scored well) have done the following...

History: Briefly gave an overview of the event their EE focused on and introduced the key figures, putting them into the context of the student's historical investigation. This was not just a narrative introduction; the introduction of the research question itself, and several competing historical perspectives, was woven into this background info.

Physics: An overview of the aerodynamic concepts that were central to the student's study, described not just as physical concepts but in reference to the parts of an airplane's wing (the student's investigation was how the shape of one piece of a plane's wing affected the generation of lift force.) The introduction section of this essay left no doubt that this student was both an airplane whiz kid as well as a real expert on these aerodynamic forces. This intro set the stage for getting an A.

Psychology: An overview of the chosen topic, why it gets comparatively little attention when compared to similar topics, and an outline of the studies chosen. This student's description of why the topic doesn't receive as much attention as it should added a strong sense of urgency to their topic AND made the introduction a little bit of an argument, making it a lot more lively than a typical overview. 

Economics: A student introduced both the economic concept they were exploring (negative externalities of consumption) as well as their specific case study for the EE, tying the two together. The student demonstrated a sound understanding of economic concepts, and applied that knowledge to their case study (modifying the standard economic graph to fit the example they had chosen before launching into their introduction and analysis of the data they found.)

First, you should consult the subject-specific EE advice for your subject, as not all subjects need to explicitly talk about methodology (as in, describe a step-by-step process.) However, all subjects do have an expectation that you "show" your methodology in some way. In a subject like History, this means including a critical analysis several of your sources, while in a Science subject it may entail an explanation of the steps you took carrying out an experiment. 

Like the section just above this one, this can be an opportunity for you to show a greater familiarity with your subject, only this goes beyond content knowledge towards a deeper understanding of how the subject operates, or how an academic person in that field should approach their work. Some of those TOK discussions you've had about the difference between knowledge in different subject areas? Yeah, that stuff is relevant here. 

Is this something that the examiners are specifically looking for? Not necessarily, but in some subjects--or with some topics--you might feel a need to justify or defend your choice. Maybe you're looking at a book that is marketed towards younger people, but you want to make an argument that the author is still presenting a complex story with literary merit. Maybe you have a topic that hasn't received the attention it deserves. Maybe your topic was something where there was universal agreement, but new information has come to light and things need to be revisited.

If you fit one of those scenarios, you may benefit from including an justification for your topic. Even if you don't fit one of these scenarios, there's nothing wrong with including a few sentences explaining the reason why this is worth studying. At worst, you're showing the examiner that you're trying to be critical. 

Keep in mind that this must go beyond simply saying "this topic is important." You also don't want to be long-winded and write an extended essay about why your extended essay matters. There is a need to be direct and forceful, but also concise. Make your case, stand by it, and move on.