A new privacy-preserving data aggregation scheme supporting anonymous authentication is proposed to address the deficiencies of existing power injection schemes in terms of data availability and user identity privacy. First, an improved Paillier encryption algorithm is employed to ensure the confidentiality of power injection data, and a Merkle tree is constructed to store the aggregated ciphertext, thereby ensuring data integrity. Next, to prevent the association between users' real identity and their pseudonyms, a one-way hash function is used to generate multiple pseudonyms for each user, thus concealing their real identities and enhancing identity privacy. Specifically, to improve authentication efficiency while preserving user privacy, a Bloom filter is used for fast pseudonym validation, and the RSA signature algorithm is used to quickly verify data integrity. Finally, theoretical analysis and performance experiments show that the proposed scheme not only satisfies security requirements but also achieves superior computational performance compared to existing schemes, making it more suitable for resource-constrained V2G networks.