Audi Ag

Nimbus Power Systems Inc.

Utc Power Corporation

Ballard Power Systems Corporation

Utc Fuel Cells, LLC

United Technologies Corporation

Matthew P Wilson

Venkateshwarlu Yadha

Michael E Gorman

Samuel J Angles

Sitaram Ramaswamy

Carl Anthony Reiser

G Michael Gron, Jr

Gennady Resnick

Christopher John Carnevale

Jeffrey G Lake

Harold T Couch

Parthasarathy Seshadri

Praveen Narasimhamurthy

Michael D Harrington

Mark J Moran

Matthew I Riley

A four-fluid bipolar plate for a fuel cell includes a nonporous sub-plate comprising a first reactant half-plate joined to a second reactant half-plate. The nonporous sub-plate includes an internal coolant passage network having coolant flow field passages extending across an active area of the fuel cell. The nonporous sub-plate defines fuel supply and fuel return internal manifolds, oxidant supply and oxidant return internal manifolds, water management supply and water management return internal manifolds, and coolant supply and coolant return internal manifolds. The internal coolant passage network may have secondary cooling functions, such as a reactant coolant loop surrounding an internal reactant internal manifold, providing a heat exchange area to cool incoming reactant gas, and cooling the interfacial and porous sub-plate seals.

Four-fluid bipolar plate for fuel cell

A fuel cell power plant includes an energy storage system connected in parallel with a fuel cell system. The fuel cell system includes a controller, a fuel flow system, an air flow system, and an internal water management system. The controller is operable to receive, as inputs, the energy storage system state of charge and the power demand from an electric load. The controller is further operable to determine a power split set point and execute commands, as output, to control operation of the air flow system, wherein the air flow system actively regulates the proportion of current flow between the fuel cell system and the energy storage system to meet the power demand of the electric load.

Fuel cell system air throttle for hybrid power control

A bipolar plate for a four-fluid fuel cell includes a nonporous sub-plate and a porous sub-plate. The nonporous sub-plate includes a water management side, an opposing reactant side, and an internal coolant passage therebetween. The porous sub-plate includes a reactant side and an opposing water management side. The reactant side includes a first reactant flow field, and the water management side is fluidly connected to the water management side of the nonporous sub-plate. Embodiments of the invention include a method to operate the four-fluid fuel cell in thermal boost mode, and a method to accumulate and retain product water.

A four-fluid bipolar plate for a fuel cell includes an oxidant flow field, a fuel reactant flow field, a dedicated coolant passage, and a water management flow field. The bipolar plate includes at least one porous layer. A first side of the porous layer is fluidly connected to the water management flow field via a plurality of pores that act as a bubble barrier. An opposing second side of the porous layer includes either the fuel reactant flow field or the oxidant flow field. In one example, the dedicated coolant passage is internal to the bipolar plate, and may be configured to flow an antifreeze-type coolant.

The performance of a fuel cell power plant that decays, in an electric vehicle which makes frequent starts, is recovered by partially shutting down the power plant. Recovery is enabled by a recovery enable flag upon conditions such as vehicle using low or no power, vehicle speed at or near zero, electric storage SOC above a threshold, and no recovery during the last half-hour (or other duration). The recovery restart resets a timer to ensure that recovery is not attempted too often. The power plant then remains in a recovery stand-by mode until a recovery restart flag is set to 1. The restart causes start-up of the fuel cell power plant, reaching an operational mode.

In-service fuel cell performance recovery

A fuel cell power plant keeps track, such as with a fuel-off timer (), of the extent to which shutdown of the fuel cell power plant has occurred, in case the fuel cell power plant is quickly commanded to resume full operation. In one embodiment, if the fuel-off timer has not timed out at the time that the fuel cell power plant is ordered to resume full operation, a fuel-on timer is set () equal to the value of the fuel-off timer when the fuel cell power plant is ordered to resume full operation. Then, the fuel cell power plant is refueled (), in a duration of time related to the setting of the fuel-off timer, rather than doing a full fuel purge.

Quick restart of fuel cell power plant as alternative to idling

The performance of a fuel cell power plant that decays, in an electric vehicle which makes frequent starts, is recovered by partially shutting down (-) the power plant. Recovery is enabled by a recovery enable flag () upon conditions such as vehicle using () low or no power (), vehicle speed at or near zero (), electric storage SOC above a threshold (), and no recovery () during the last half-hour (or other duration). The recovery restart resets a timer () to ensure () that recovery is not attempted too often. The power plant then remains in a recovery stand-by mode () until a recovery restart flag () is set to 1 (). The restart causes start-up of the fuel cell power plant (), reaching an operational mode ().

Ejectors () are configured to receive fresh fuel gas at the motive inlet () and to receive fuel recycle gas at the suction inlet (). Each ejector is disposed either a) within a fuel inlet/outlet manifold () or adjacent to and integral with the fuel inlet/outlet manifold. The ejector draws fuel recycle gas directly from the fuel outlet manifold and, after mixing with fresh fuel, is expanded () to lower the pressure and is then fed directly into the fuel inlet manifold (). The ejector may be within an external manifold () or an internal manifold (). The ejector () may be formed of perforations clear through a plate (), which is closed on either side by other plates (), or the ejector may be formed by suitable sculpture of fuel cells () having internal fuel inlet () and fuel outlet () manifolds.

Fuel cell fuel recycle ejectors disposed in fuel manifold

A fuel cell power plant () includes a stack () of fuel cells, each of which have an anode (), a cathode (), and a PEM () disposed between the anode and the cathode. A controller () recognizes an indication () of no load demand () by a load (), to operate () an air recycle loop (-) utilizing the process air blower () and transfer the power output () of the stack from the load () to an auxiliary load (), comprising a resistance which will consume a predetermined small amount of power in response to the current applied thereto, when the stack operates at a critical voltage above which fuel cell corrosion is unacceptable. Fuel and air will also be reduced (). The controller may cause increased cathode recycle when the critical voltage is reached and increased air when the voltage is a fraction of a volt below the critical voltage.

Low power control of fuel cell open circuit voltage

The invention is a hydrogen passivation shut down system for a fuel cell power plant (). During shut down of the plant (), hydrogen fuel is permitted to transfer between an anode flow path () and a cathode flow path (). A controlled-oxidant flow device () near an oxygen source () permits a minimal amount of atmospheric oxygen to enter the power plant () during shut down to equalize pressure between ambient atmosphere and the flow paths () and to keep limited atmospheric oxygen entering the power plant () through the device () as far as possible from fuel cell flow fields (). A non-leaking hydrogen inlet valve (), a non-leaking cathode exhaust valve (), and a combined oxidant and fuel exhaust line () also minimize penetration of oxygen into the shut down power plant ().

Hydrogen passivation shut down system for a fuel cell power plant

A fuel cell power plant () having a stack of fuel cells (), each having an anode (), a fuel reactant gas flow field plate (), a cathode (), an oxidant reactant gas flow field plate (), and an electrolyte () between the anode and cathode. The stack has coolant channels (), an air blower (), air inlet () and outlet () valves, and a cathode recycle loop using either the primary air blower or a cathode recycle blower (). A shutdown process includes recycling air through the cathodes with only one of an air inlet valve or air exit valve closed, while applying fresh fuel and recycling fuel through the anodes until oxygen is about 4% or less, or average cell voltage is about 0.2 or less, or for predetermined period of time.

Avoiding coolant slump into reactant fields during PEM fuel cell shutdown

The air blower () of a fuel cell power plant () is used to force water out of the coolant flow fields () of a fuel cell stack (), a coolant pump () and a heat exchanger () through a valve () which is closed during normal operation. The water removal occurs as part of a shutdown procedure in which the fuel cell stack continues to operate so that it provides the power for the air pump and to assist in water removal (such as retaining low vapor pressure). The water flow to an accumulator () is blocked by a valve () during the shutdown procedure.

Purging water with reactant air pump powered by operational fuel cell system during shutdown

The outflow of coolers or water transport plates of a fuel cell stack () is fed to the inlet of a gas/liquid separator (), the liquid output of which is connected through a primary pump () to a liquid accumulator (). A secondary pump () connected to the liquid output () of the liquid accumulator is fed to the principal inlet () of an eductor (), the secondary inlet being connected to the gas output of the gas/liquid separator. The outlet () of the eductor is fed through a conduit () to a point below liquid level in the liquid accumulator. Thus, failure of the secondary pump () will not cause cavitation of the primary pump () through the eductor so that coolant will continue to flow through the fuel cell stack. A demineralizer () is fed through a pressure reducing orifice () from the outlet of the secondary pump.

Growing community of inventors

Groton, CT, United States of America

Matthew P Wilson