Battery system, preferably for a hybrid or electric vehicle, wherein the battery system comprises: one or more battery packs each having one or more cells which are electrically connected and configured to provide a voltage, preferably a high voltage, at a respective battery pack output; and an integration device electrically connected to the battery pack outputs and configured to receive and combine the power of the battery packs, thereby forming a sum power supplied to a sum voltage output of the integration device; where in the integration device comprises a filter device which is configured to protect the battery packs from interferences, for example interferences generated by an electrical component connected to the sum voltage output.