Heat battery assemblies and monitoring system therefor

A thermal energy storage system comprising a thermal energy store containing a single or a plurality of battery casings having

• internal heat exchangers, phase change materials, and an integral system controller for controlling operation of the thermal energy store,
• wherein the integral system controller is adapted to determine the status of the batteries within the thermal energy storage system via the following series of algorithms:
• a) If (Q=1 and δP≤PL1) OR (Q=1 and PBC≤PA), then:
• Battery case is not air tight
• Activate appropriate alarm/warning
• Put this battery in standby mode (Q=0)
• b) If (Q=1 and δP≥PL2) OR (Q=1 and PBC≥PL3), then:
• Battery case pressure is exceeding the maximum operating limit
• Activate appropriate alarm/warning
• Put this battery in standby mode (Q=0)
• c) If (Q=0 and TBC≤TE), then:
• Put this battery in charging mode (Q=1)
• SOC=0
• d) If (Q=1 and δT≥TL2) OR (Q=1 and TBC≥TL3), then:
• Battery case temperature is exceeding the maximum operating limit
• Activate appropriate alarm/warning
• Put this battery in standby mode (Q=0)
• e) If (PAB1≤ABS(δP)≤PAB2) OR (PA≤PBC≤PB) OR (TE≤TBC≤TF) OR TEF1≤ABS(δT)≤TEF2), then the battery is operating in zone AB corresponding to zone EF SOC=100·mPCM·Cps·δTs/ETOT
• f) If (PBC1≤ABS(δP)≤PBC2) OR (PB≤PBC≤PC) OR (TF≤TBC≤TG) OR (TFG1≤ABS(δT)≤TFG2), then the battery is operating in zone BC corresponding to zone FG SOC=100·(EsL+FBC·CBC·PB)/ETOT
• g. If (PCD1≤ABS(δP)≤PCD2) OR (PC≤PBC≤PD) OR (TG≤TBC≤TH) OR (TGH1≤ABS(δT)≤TGH2), then the battery is operating in zone CD corresponding to zone GH SOC=100·(ESL+EL+mPCM·CpL·δTL)/ETOT
• wherein the preceding symbols are defined as follows:
• Q=Battery charging state;
• δP=Rate of pressure change;
• ABS(δP)=absolute value of Rate of pressure change;
• PL1=Minimum rate of pressure change limit;
• PBC=Battery case pressure;
• PA=Base reference pressure;
• PL2=Maximum rate of pressure change limit;
• PL3=Maximum battery case working pressure;
• TBC=Battery case temperature;
• TE=Base reference temperature;
• SOC=State of charge of the battery;
• δT=Rate of temperature change;
• ABS(δT)=absolute value of rate of temperature change;
• TL2=Maximum rate of temperature change limit;
• TL3=Maximum battery case working temperature;
• PAB1=Rate of pressure change in zone AB—Lower limit;
• PAB2=Rate of pressure change in zone AB—Upper limit;
• PA=Battery pressure where the phase change material remains in a solid state;
• PB=Battery pressure where the phase change material remains in a solid state but begins to change phase from solid to liquid;
• TE=Battery temperature where the phase change material remains in a solid state;
• TF=Battery temperature where the phase change material remains in a solid state but begins to change phase from solid to liquid;
• TEF1=Rate of temperature change in zone EF—Lower limit;
• TEF2=Rate of temperature change in zone EF—Upper limit;
• δTs=Temperature difference between battery temperature IBC and minimum reference temperature TE;
• PBC1=Rate of pressure change in zone BC—Lower limit;
• PBC2=Rate of pressure change in zone BC—Upper limit;
• PC=Battery pressure where the phase change material has changed from solid to liquid);
• TG=Battery temperature at a pressure where the phase change material has changed from solid to liquid;
• TFG1=Rate of temperature change in zone FG—Lower limit;
• TFG2=Rate of temperature change in zone FG—Upper limit;
• FBC=Scaling factor for—Zone BC;
• CBC=Correction factor (Power & PCM);
• PCD1=Rate of pressure change in zone CD—Lower limit;
• PGD2=Rate of pressure change in zone CD—Upper limit;
• PC=Battery pressure where the phase change material has changed from solid to liquid;
• PD=Battery pressure at a maximum pressure limit;
• TG=Battery temperature at a battery pressure where the phase change material has changed from solid to liquid;
• TH=Battery temperature at a maximum temperature limit;
• TGH1=Rate of temperature change in zone GH—Lower limit;
• TGH2=Rate of temperature change in zone GH—Upper limit;
• and
• δTL=Temperature difference between battery temperature TBC and upper temperature of the melting zone TG.