The Battle of Lodi happened in 1796 in the northern part of what is now Italy.
The battle itself was not very significant. The French were fighting the Austrian army and were trying to prevent that army from escaping across a river at the town of Lodi.
The French failed to do this -- they defeated the Austrians who fought them, but the Austrians they defeated were trying mainly to delay the French so the main Austrian army could escape. The main army did escape, so the battle was not a huge victory.
However, the battle helped make the legend of Napoleon. He exaggerated the scale of the victory and his part in it. Because of this, he became more of a hero to the French. This eventually helped him become ruler of France. So the battle is mostly important because it gave Napoleon a better image and more prestige in France and helped him eventually become ruler.