The advancement of technological capabilities within lithium battery enterprises crucially facilitates the high-quality development of the new energy industry. This study aims to empirically investigate the impact of mergers and acquisitions (M&A) on the technological innovation capacities of these enterprises, with a specific focus on the lithium battery sector in China. Utilizing data from 34 publicly listed companies spanning the period from 2012 to 2022, we employ the multi-period double-difference method for comprehensive analysis. Researchers have observed that the implementation of merger and acquisition (M&A) strategies by new energy companies leads to an approximately 1.5 percentage point increase in their technological innovation level. However, the improvement in the green technological innovation level is not significant. After a series of robustness tests, the aforementioned conclusion remains valid. Additionally, with the enhancement of firms’ knowledge absorption capacity and regional intellectual property protection, M&A activities can further promote technological innovation in new energy companies and contribute to the enhancement of green technological innovation. Heterogeneity analysis has revealed that technological M&A crucially facilitates the improvement of technological innovation levels among listed companies in the lithium battery industry. Implementing M&A strategies not only benefits the enhancement of firms’ technological innovation levels but also significantly fosters green technological innovation. Furthermore, further research has indicated that changes in the level of green technological innovation after the implementation of M&A strategies by new energy companies facilitate the reduction of industrial wastewater and sulfur dioxide emissions. The main innovation of this study, which utilizes new energy companies as the research object, is as follows: it reveals the causal relationship and regulatory mechanism between M&A, technological innovation, and green technological innovation in new energy companies. Furthermore, the study analyzes the mechanism that promotes green technological innovation in new energy companies from the intellectual property protection perspective. Moreover, it assesses the heterogeneous impacts of changes in both technological innovation levels and green technological innovation levels on environmental governance after the implementation of M&A activities.