A cell stack including; a stacked body including a plurality of cell frames each having a bipolar plate whose outer periphery is supported by a frame member; and a pair of end plates that tighten the stacked body from both sides of a stacking direction thereof, wherein an area S [cm.sup.2] of each cell frame as viewed from the stacking direction of the stacked body and a length W [mm] in the stacking direction of the stacked body satisfies a relationship 0.05≤W/S≤0.9.

A battery according to an embodiment of the present invention includes: a plurality of tanks (2) storing electrolyte containing ions of which valence is changed; a cell (1) configured to cause oxidation-reduction of the electrolyte so as to be charged or discharged; a pipe (3) connecting the plurality of tanks and the cell; and a pump (4) configured to circulate the electrolyte between the plurality of tanks and the cell through the pipe. The battery according to an embodiment of the present invention includes a container (5) housing the plurality of tanks (2), the cell (1), the pipe (3), and the pump (4). The container has a bottom (51), a side (52), and a top (53). Accordingly, the battery in an embodiment of the present invention can be installed easily and its installation area can be reduced.

Systems and methods for managing flow batteries utilize a battery management controller (BMC) coupled between a flow battery and a DC/DC converter, which is coupled to an electrical grid or a photovoltaic device via an inverter. The inverter converts an AC voltage to a first DC voltage and the DC/DC converter steps down the first DC voltage to a second DC voltage. The BMC includes a first power route, a second power route, and a current source converter coupled to the second power route. The BMC initializes the flow battery with a third DC voltage using the current source converter until a sensing circuit senses that the voltage of the flow battery has reached a predetermined voltage. The sensing circuit may include a capacitor, which has a small capacitance and is coupled across each cell of the flow battery, coupled in series between two resistors having very large resistances.

In one embodiment of the present invention, it is provided a method of manufacturing a separator comprising:

preparing expansion graphite; pulverizing the expansion graphite; mixing the expansion graphite and polymer; and forming a separator by molding the mixture.

The redox flow cell comprises a reaction cell having two electrode chambers for catholyte and anolyte, which are each connected to at least one store for liquid and are separated by an ion-conducting membrane, and which are equipped with electrodes, wherein the electrode chambers are each filled with electrolyte solutions comprising redox-active components dissolved or dispersed in an electrolyte solvent, as well as optionally conducting salts dissolved therein and optionally further additives. The redox flow cell is characterized by the anolyte comprising a redox-active component having one to six residues of formula I in the molecule or having one to six residues of formula II in the molecule and by the catholyte comprising a redox-active component having one to six residues of formula III in the molecule or having iron salts or by the anolyte and the catholyte having a redox-active component comprising one to six residues of formula I or of formula II in combination with one to six residues of formula III in the molecule ##STR00001##
wherein R.sub.1 is a covalent C—C-bond or a divalent bridge group, R.sub.2 and R.sub.3 independently of one another represent alkyl, alkoxy, haloalkyl, cycloalkyl, aryl, aralkyl, heterocyclyl, halogen, hydroxy, amino, nitro or cyano, X is a q-valent inorganic or organic anion, b and c independently of one another are integers from 0 to 4, q is an integer from 1 to 3, a is a number of value 2/q, and R.sub.4, R.sub.5, R.sub.6 and R.sub.7 independently of one another represent alkyl, cycloalkyl, aryl or aralkyl.

Provided is a porous electrode substrate capable of reducing a drop in electromotive force when used in a battery. This porous electrode substrate comprises a carbon fiber sheet wherein carbon fibers are bound by a binder. For dust of 0.3 μm or more in particle size, the dust generation amount per 1 m.sup.2 of the porous electrode substrate is 120,000/m.sup.2 or less, as determined by the following method: dust particles in a gas obtained by suctioning at 47.2 mL/s for 40 minutes using a dust collecting hood having an opening of 500 mm×100 mm while traveling the sheet at a speed of 10 m/min from a position 200 mm below the sheet are used; the number of dust particles having a diameter within a predetermined range is measured by a particle counter; and the measured value is divided by 200 m.sup.2, which is a suction area, and the resulting value is defined as a dust generation amount per 1 m.sup.2.

A redox flow battery includes a redox flow cell and a supply and storage system external of the redox flow cell. The supply and storage system includes first and second electrolytes for circulation through the redox flow cell. The first electrolyte is a liquid electrolyte having electrochemically active manganese species with multiple, reversible oxidation states in the redox flow cell. The electrochemically active manganese species may undergo reactions that cause precipitation of manganese oxide solids. The first electrolyte includes an inhibitor that limits the self-discharge reactions. The inhibitor includes an oxoanion compound.

A flow battery system includes a first tank including a hydrogen reactant, a second tank including a bromine electrolyte, and at least one cell including a first electrolyte side operably connected to the first tank and a second electrolyte side operably connected to the second tank. The battery system further includes a direct connection line directly connecting the first tank and the second tank and configured such that the hydrogen reactant passes between the first tank and the second tank.

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.

Means for maintaining level complementary electrolytes inflow battery tanks has first and second interconnected tanks 2, 3. The first tank 2 contains positive electrolyte, 2b, and the second tank containing negative electrolyte 3b. Both tanks have a void 2a and 3 a respectively, for air or other noble gases. The tanks themselves are connected by pipes; a lower tank connecting pipe 4, an upper tank connection pipe 5 with an inter-pipe connecting pipe 6 therebetween. The peak of the lower tank connection pipe 4a is designed to remain below the normal liquid level 7 of both tanks, in contrast to the upper tank connection pipe 5 which remains above the desired liquid level 7.