This paper presents a cost modeling framework for battery systems. Based on findings in battery cost modeling literature, there is a need for scalable, systematic frameworks to model cost. The framework in this paper, which is developed with a systems approach in mind, incorporates parametric cost models that consider scaling in component rating, future cost prediction and economies of scale with a limited set of tunable parameters per component. This framework is employed to construct an instance of a novel battery architecture, the module level converter topology, in a scalable way using different classes for (sub-)systems and indivisible components, based on the desired power output and energy content of the system. By doing so, the system costs of the novel hybrid battery architecture are compared to a baseline battery topology in terms of cost decomposition. The prospects of this novel architecture are also mapped out in terms of production volume and future component costs.