Cold plate with orifice-type manifolds and 3-pass channels for high temperature uniformity in battery packs

Flow maldistribution in liquid-cooled cold plates is often overlooked in battery thermal management system (BTMS) design, despite its critical influence on cell-to-cell temperature uniformity at the pack level. This study proposes a novel bottom-cooled liquid cold plate that integrates orifice-type manifolds with a parallel 3-pass channel configuration to systematically address coolant flow maldistribution and temperature gradients in battery packs. First, the effects of flow maldistribution in parallel-straight-channel cold plates are quantified, revealing a flow maldistribution factor of up to 99.6%, which results in a row-to-row cell temperature difference of 3.03 °C at 2-C discharge. By introducing orifice-type manifolds, the flow maldistribution factor is reduced to 18.8%, leading to a 72.4% reduction in temperature variation across cell rows. A parametric study identifies an optimal manifold-to-port area ratio of approximately unity, providing the best trade-off between flow uniformity improvement and pressure drop penalty. To further mitigate temperature non-uniformity in the battery pack along the overall streamwise direction, a parallel 3-pass channel configuration is introduced, which reduces the temperature variation across cell columns by 67.8%. Furthermore, a parametric study reveals that the spanwise temperature uniformity in the battery pack decreases with the channel pitch for the parallel 3-pass channel configuration and the optimal 3-pass channel pitch is found to be 47.6 mm. Finally. compared with a conventional-serpentine-channel design, the proposed cold plate achieves a 53.3% reduction in overall cell-to-cell temperature difference (from 5.89 °C to 2.75 °C) while simultaneously reducing pressure drop by 75.7% at 2-C discharge and total flow rate of 23 L/min. Comparable improvements in thermal-hydraulic performance are also achieved under higher thermal loads of 3-C discharge and larger total flow rate of 35 L/min. The proposed design is lightweight, scalable, and compatible with conventional manufacturing processes, offering practical design guidelines for high-performance liquid cooling systems in battery packs.