High Density Bidirectional Lithium Ion Battery Disconnect Switch With Ultralow Specific On-Resistance

A battery disconnect switch (BDS) with high cell density is researched in this paper. Compared with the conventional structure, the proposed BDS reduces the cell pitch by leading P+ region from the X direction to Z direction, further improving the cell density and decreasing the total BDS resistance simultaneously. Based on this, we have designed a BDS that, usually applied in battery management system (BMS), can realize bidirectional conduction and blocking. Furthermore, a 22-V trench power MOSFET in BDS is analytically designed and experimentally implemented, which obtains the ultralow specific on-resistance (R on,sp ) of 3.68 mΩ•mm ² at V gs = 4.5 V.