Design and Implementation of On-board Electrical Power ... - OUFTI-1

Design and Implementation of On-board Electrical Power ... - OUFTI-1 Design and Implementation of On-board Electrical Power ... - OUFTI-1

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Parameter SLPB723870H4 SLPB554374HNominal Capacity TYP 1,500 mAh TYP 1,250 mAhNominal Voltage 3.7V 3.7VCharge ConditionMax. Current 1C(1,500mAh) 1C(1,250mAh)Voltage 4.20 ± 0.03V 4.20 ± 0.03VDischarge ConditionMax. Current 20C(30,000mAh) 15C(18,750mA)Cut-Off Voltage 2.7V 2.7VAC-Impedance.(mΩ ) MAX. 9.0 (1kHz) MAX. 16.0 (1kHz)Operating T ◦ Charge 0 ◦ C to 45 ◦ C 0 ◦ C to 45 ◦ CDischarge -20 ◦ C to 60 ◦ C -20 ◦ C to 60 ◦ CWeight(Max.) 41.0 g 34.0 gEnergy DensityVolumetric 278 Wh/l 287 Wh/lGravimetric 145 Wh/kg 152 Wh/kgTable 3.3: Characteristics of two candidate KOKAM batteries [20].Figure 3.17: Dimensions of the KOKAM SLPB554374H battery [20].to 4,720mW with the power budget worksheet (Chapter 4). The corresponding maximumconsumed current is 1.75A at 2.7V and 1.12A at 4.2V. This corresponds respectively todischarge rates of 1.4C and 0.9C. Figure 3.18 shows the charge characteristics of KOKAMbatteries. Figure 3.19 and 3.20 show their discharge characteristics.Figure 3.18 shows that the batteries are not fully charged when their voltage reaches 4.2V.The dissipation system on the EPS is a shunt regulator (Chapter 5). Another system couldbe to disconnect the batteries when their voltage reaches 4.2V. The use of a shunt regulatorwill allow the batteries to reach the full charge. This is still to be confirmed by tests.32

Figure 3.18: Charge characteristics of KOKAM SLPB554374H (KOKAM Datasheet).Figure 3.19 shows that, for a DoD of 13% (which corresponds to 162 mAh) and a dischargerate under 1C, the voltage should stay between 4V and 4.2V (at 23 ◦ C and begin of life).Figure 3.19: Variation of voltage of KOKAM SLPB554374H during discharge for severaldischarge rates [20].The temperature of the batteries during charge must be between 0 ◦ C and 45 ◦ C or theycould suffer permanent damages. The spacers between the batteries card and the EPS cardwill have a high thermal resistance. Simulations show that, with this solution, the temperature33

Parameter SLPB723870H4 SLPB554374HNominal Capacity TYP 1,500 mAh TYP 1,250 mAhNominal Voltage 3.7V 3.7VCharge ConditionMax. Current 1C(1,500mAh) 1C(1,250mAh)Voltage 4.20 ± 0.03V 4.20 ± 0.03VDischarge ConditionMax. Current 20C(30,000mAh) 15C(18,750mA)Cut-Off Voltage 2.7V 2.7VAC-Impedance.(mΩ ) MAX. 9.0 (1kHz) MAX. 16.0 (1kHz)Operating T ◦ Charge 0 ◦ C to 45 ◦ C 0 ◦ C to 45 ◦ CDischarge -20 ◦ C to 60 ◦ C -20 ◦ C to 60 ◦ CWeight(Max.) 41.0 g 34.0 gEnergy DensityVolumetric 278 Wh/l 287 Wh/lGravimetric 145 Wh/kg 152 Wh/kgTable 3.3: Characteristics <strong>of</strong> two c<strong>and</strong>idate KOKAM batteries [20].Figure 3.17: Dimensions <strong>of</strong> the KOKAM SLPB554374H battery [20].to 4,720mW with the power budget worksheet (Chapter 4). The corresponding maximumconsumed current is 1.75A at 2.7V <strong>and</strong> 1.12A at 4.2V. This corresponds respectively todischarge rates <strong>of</strong> 1.4C <strong>and</strong> 0.9C. Figure 3.18 shows the charge characteristics <strong>of</strong> KOKAMbatteries. Figure 3.19 <strong>and</strong> 3.20 show their discharge characteristics.Figure 3.18 shows that the batteries are not fully charged when their voltage reaches 4.2V.The dissipation system on the EPS is a shunt regulator (Chapter 5). Another system couldbe to disconnect the batteries when their voltage reaches 4.2V. The use <strong>of</strong> a shunt regulatorwill allow the batteries to reach the full charge. This is still to be confirmed by tests.32

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