ESS Tech, Inc.

Methods and systems are provided for transporting and hydrating a redox flow battery system with a portable field hydration system. In one example, the redox flow battery system may be hydrated with the portable field hydration system in a dry state, in the absence of liquids. In this way, a redox flow battery system may be assembled and transported from a battery manufacturing facility to an end-use location off-site while the redox flow battery system is in the dry state, thereby reducing shipping costs, design complexities, as well as logistical and environmental concerns.

Systems and methods are provided for managing an energy storage system. In one example, a method may include directing energy stored in the energy storage system to a cryptocurrency mining system and another consumer responsive to conditions. Other consumers may include a third party consumer of energy and conditions may include current and predicted cryptocurrency values and current and predicted availability of cyclically available renewable energy.

Systems and methods for operating an electric energy storage device are described. The systems and methods may generate a state of charge estimate that is based on negative electrode plating. An overall state of charge may be determined from the state of charge estimate that is based on negative electrode plating and a state of charge estimate that is not based on negative electrode plating.

A hybrid redox fuel cell system includes a hybrid redox fuel cell including an anode side through which a reductant is flowed and a cathode side through which liquid electrolyte is flowed, and a catalyst bed fluidly connected to the cathode side of the hybrid redox fuel cell, the catalyst bed including a substrate layer and a catalyst layer spiral wound into a jelly roll structure. Furthermore, the liquid electrolyte includes a metal ion at a higher oxidation state and the metal ion at a lower oxidation state, and power is generated at the hybrid redox fuel cell by way of reducing the metal ion from the higher oxidation state to the lower oxidation state at the cathode side while oxidizing the reductant at the anode side.

A hybrid redox fuel cell system includes a hybrid redox fuel cell including an anode side through which a reductant is flowed and a cathode side through which liquid electrolyte is flowed, and a trickle bed reactor including a catalyst bed fluidly connected to the cathode side of the hybrid redox fuel cell. Furthermore, the liquid electrolyte includes a metal ion at a higher oxidation state and the metal ion at a lower oxidation state, and power is generated at the hybrid redox fuel cell by way of reducing the metal ion at the higher oxidation state to the lower oxidation state at the cathode side while oxidizing the reductant at the anode side.

A hybrid redox fuel cell system includes a hybrid redox fuel cell and an electrochemical cell. The hybrid redox fuel cell includes an anode side through which hydrogen is flowed and a cathode side through which liquid electrolyte is flowed, the liquid electrolyte including a metal ion at a higher oxidation state and the metal ion at a lower oxidation state. An anode side of the electrochemical cell is fluidly connected to the cathode side of the hybrid redox fuel cell. At the hybrid redox fuel cell, power is generated by reducing the metal ion at the higher oxidation state to the lower oxidation state at the cathode side while oxidizing the reductant at the anode side. At the anode side of the electrochemical cell, the metal ion at the lower oxidation state is oxidized to the higher oxidation state while the power is generated.

Systems and methods are provided for mechanical pretreatment of bipolar plates, for example, for plating electrodes in redox flow batteries. In one example, a method for disrupting surfaces of a bipolar plate may include pressing the bipolar plate between imprint plates, and removing the pressed bipolar plate from the imprint plates prior to use in a redox flow battery. In some examples, the pressed bipolar plate may include negative indentations from at least one of the imprint plates. In some examples, the imprint plates may be patterned meshes, such that the negative indentations may include patterns of asymmetric protrusions. In this way, the bipolar plate may be pretreated via pressing so as to reduce wear to manufacturing equipment (relative to other mechanical pretreatment processes, for example) while maintaining electrochemical performance of the redox flow battery.

A method of cleansing a redox flow battery system may include operating the redox flow battery system in a charge, discharge, or idle mode, and responsive to a redox flow battery capacity being less than a threshold battery capacity, mixing the positive electrolyte with the negative electrolyte. In this way, battery capacity degradation following cyclic charging and discharging of the redox flow battery system can be substantially reduced.

A redox flow battery and battery system are provided. In one example, the redox flow battery includes a set of pressure plates having a first pressure plate at a first terminal end and a second pressure plate at a second terminal end, the second terminal end and the first terminal end positioned on opposing longitudinal sides of the redox flow battery. The redox flow battery further includes a first cell stack positioned longitudinally between the first pressure plate and the second pressure plate, each of the first and second pressure plates includes a plurality stacking detents on a first flange and a plurality of stacking protrusions on a second flange, and the first flange and the second flange arranged on opposing vertical sides of the redox flow battery.

Systems and methods are provided for electrolyte distribution, rebalancing, and storage in a redox flow battery system. In one example, the redox flow battery system may include a plurality of redox flow battery cells and a plurality of storage tanks respectively fluidically coupled thereto, wherein a gauge pressure in each of the plurality of storage tanks may be maintained below a relatively low pressure (for example, below 2 psi). In some examples, the redox flow battery system may further include a plurality of rebalancing cells respectively fluidically coupled to the plurality of storage tanks, each of the plurality of rebalancing cells including a stack of internally shorted electrode assemblies. In this way, the redox flow battery system may be operated at less than the relatively low pressure, such that multiple space effective (for example, prismatic and relatively small) storage tanks may be included.