Abstract: Battery packs including electrochemical cells, associated components, and arrangements thereof are generally described. In some aspects, battery packs with housings that undergo relatively little expansion and contraction even in cases where electrochemical cells in the battery pack undergo a relatively high degree of expansion and contraction during charging and discharging are provided. Battery packs configured to apply relatively high magnitudes and uniform force to electrochemical cells in the battery pack, while in some cases having high energy densities and a relatively low pack burden, are also provided. In certain aspects, arrangements of electrochemical cells and associated components are generally described. In some aspects, thermally conductive solid articles that can be used for aligning components of the battery pack are described. In some aspects, thermally insulating and compressible components for battery packs are generally described.

Abstract: A system for protecting at least one electrochemical cell, comprising circuitry configured to disconnect the at least one electrochemical cell at a first threshold current magnitude based on a first current flow direction through at least one relay and at a second threshold current magnitude based on a second current flow direction through the at least one relay, wherein the first current flow direction is different from the second current flow direction. A method for electrochemical cell protection. A system comprising circuitry configured to disconnect at least one portion of a circuit at a first threshold current magnitude based on a first current flow direction through at least one relay and at a second threshold current magnitude based on a second current flow direction through the at least one relay. A method for protecting at least one portion of a circuit.

Abstract: A battery pack comprising a substrate comprising a battery power bus integrated into the substrate; and a pack controller; and at least one electrochemical cell connected directly to the substrate. A printed circuit board comprising a power bus integrated into the printed circuit board, wherein the power bus is connected to and configured to transfer power to and/or from at least one electrochemical cell; and at least one controller configured to control the at least one electrochemical cell. A thermal management system comprising at least one electrochemical cell; and a substrate directly connected to the at least one electrochemical cell and configured to transfer heat, power, and signals between the substrate and the at least one electrochemical cell. A thermal management method. A method of assembling a battery pack, comprising attaching at least one electrochemical cell of the battery pack directly to a substrate at least in part by welding.