This study presents a comparative analysis of high-power (HP) and high-energy (HE) INR21700 lithium-ion batteries, which are Samsung 30T (3.0Ah) and 50E (4.9Ah) respectively, examining their design differences and performance characteristics. First, this paper conducted a literature review about battery teardown data, summarized key parameters and revealed that the HP cell has higher porosity, thicker current collectors, and thinner electrode coatings compared to the HE cell. Additionally, this HE cell incorporates approximately 6% silicon oxide in its graphite anode to increase energy density. Second, extensive cell-level tests were conducted, including High Pulse Power Characterization (HPPC) and constant-current discharge tests at various C-rates (0.05C, 0.5C, 1C, and 2C) across temperatures from -20°C to 40°C, as well as aging tests. Results demonstrated that the HP cell maintains a low terminal voltage drop (<0.2V) during 2C discharge from open circuit voltage at 25°C and 40°C. However, this drop increases significantly (>0.5V) at low temperatures (-10°C and -20°C). In contrast, the HE cell, while offering higher capacity, experiences more substantial terminal voltage drops in all cases. The HP cell showed good lifetime performance that can maintain 80% capacity after 1500 cycles under 2.8C fast-charge and dynamic drive cycle discharge. The HE cell only maintained 92% capacity after 200 cycles under 1C charge and dynamic drive cycles. These results align with material theory, suggesting that introducing silicon into the anode reduces cycle stability. Third, Pseudo-two-dimensional (P2D) physicochemical models were constructed for both battery types using the physical parameters obtained from teardown analysis. These P2D models, validated against discharge tests, showed good agreement with experimental data (within 5% error at 25°C). This comprehensive study provides insights into power-energy density trade-offs and demonstrates the capabilities of P2D models in predicting battery performance. The findings can guide future battery development and model refinement.