Abstract: A method of determines one or more voltage threshold values for controlling a cooling of battery cells. The method includes determining, during e.g. charging of the battery cells, a charging voltage threshold value for starting or increasing a battery cell cooling, corresponding to a voltage across a reference set of battery cells at which a rate of change of temperature with respect to voltage of the reference set goes above a charging temperature rate threshold value. A method for using such one or more voltage threshold values for controlling a cooling of the battery cells, by comparing a measured voltage across the battery cells against the voltage threshold value(s) is also provided.

Abstract: A method of determining ageing of a mixed electrode of a full cell lithium ion battery is presented. The method includes obtaining a voltage hysteresis of the full cell lithium ion battery by comparison of a charging voltage to a discharging voltage at a specific state of charge, SOC. The specific SOC is in a range from 0% to 20% of a maximum SOC. The method further includes determining ageing of a volume expanding component of the mixed electrode based on the obtained voltage hysteresis.

Abstract: An electric energy storage system for a vehicle, comprising a battery unit, a easing enclosing the battery unit, a cooling system comprising at least one coolant conduit arranged for cooling of the at least one battery tint during normal operation of the energy storage system by circulating coolant fluid through the at least one, coolant conduit, a means for detecting a thermal runaway within the electric energy storage system, a valve arrangement being configured to respond to the detection of a thermal runaway by releasing coolant fluid from the cooling system into the casing, foam-forming substance being configured to produce a foam when coming into contact with the coolant fluid and/or when the coolant fluid is released into the casing.

Abstract: A safety system for detecting a critical condition in a battery pack. The safety system includes a control unit configured to obtain measurement data relating to a battery unit voltage and/or a battery unit temperature of at least some of the plurality of battery units, and to, based on the obtained measurement data, detect a critical condition of the battery pack, a stand-alone power supply configured to supply electric power to the safety system, a stand-alone communication interface configured to provide and/or communicate information relating to any critical condition of the battery pack detected by the control unit.