A modular thermal management system for a battery in an electric vehicle is provided. The thermal management system includes a battery module having a plurality of module ports for conducting heat exchange fluid to regulate temperature in a traction battery. The thermal management system also includes a manifold having a plurality of connector ports corresponding to the plurality of module. A retention feature is located on the manifold or the battery module for securing the manifold to the battery module to ensure the connector ports remain fluidly sealed to the module ports.