1. Warm oil in a large saucepan over medium-high heat. Add onion, celery and carrots and cook, stirring often, until softened but not browned, 3 to 5 minutes. Add garlic and sauté 1 minute longer. Stir in beans, tomatoes, broth and thyme. Season with salt and pepper.
2. Bring to a boil, then reduce heat to medium-low and simmer for 10 minutes. Add pasta and cook, stirring often, until the pasta is al dente, 10 to 12 minutes longer. Season again with salt and pepper. Thin with more broth if desired.
3. Let cool, cover and refrigerate until ready to use. To pack, rewarm over medium-low heat, stirring often, and ladle into a thermos.