Abstract: Modular battery system with at least two battery modules (114, 115), wherein each battery module comprises a cooling member (120), through which a coolant (121) at least partially flows, and a battery cell (122), wherein the battery cell (122) is disposed at the cooling member (120) such that a heat-conducting contact is set up between the battery cell and the cooling member and a coolant supply is provided by way of a coolant line (123) for distributing the coolant at the cooling member (120) or for draining the coolant from the cooling member, wherein the coolant line comprises coolant line modules that can be connected together and that form the coolant line at least partially, and wherein a diverting unit (134) is provided in the coolant line for adjusting the flow length of the coolant in the coolant supply to divert the flow direction of the coolant in the coolant line, and the coolant line comprises two flow channels (126, 127) at least in a longitudinal section, the coolant being fed substantially in

Abstract: A modular battery unit with at least two battery cells (1-6) and a heat sink (8), which is arranged between the battery cells (1-6), conforms laterally to the battery cells, has a cooling medium flowing through it and, on the one hand, transports heat which has developed in the battery cells away in a suitable manner and, on the other hand, supports the battery cells, and with two covering caps (11, 12), which can be arranged on the heat sink, wherein a first one of the two covering caps (11) is provided for closing the first end face of the heat sink and a second one of the two covering caps (12) is provided for closing the second end face of the heat sink and an inlet (16) and an outlet (17) for the cooling medium are provided, and wherein the inlet and/or the outlet of the cooling medium is arranged at the first covering cap (11) or the second covering cap (12).