Thermal battery for heating vehicles

A system and a method for heating a component of an electric vehicle may be particularly beneficial in cold weather places and/or during winter time. The vehicle may be primarily powered by a main battery. The system may include a supplementary battery being metal-air battery including an electrolyte, for extending the driving range of the electric vehicle and a reservoir tank for holding an electrolyte volume for the metal-air battery, the electrolyte may be heated to a desired temperature. The system may further include a heat exchanger for conveying heat from the electrolyte volume, said heat is conveyable to said passenger's cabin.

BACKGROUND

Heating electric vehicles using a conventional air-conditioning system, in particular at colder places, consumes large amount of the electric power stored in the vehicle's main battery, thus will probably reduce the traveling range of the vehicles. In a vehicle powered by an internal combustion engines, heat produced during the combustion is used to heat other components of the vehicle, such as the passenger's cabin or the driver's seat. This option of using excess thermal energy from the vehicle's motor does not exist in electric vehicles.

Metal-Air electrical cells are known in the art. Such Metal-Air cell or battery includes a metal anode, including for example, aluminum, zinc, lithium, beryllium, calcium, or the like and a gas diffusion cathode. The chemical reaction that produces electricity in the battery is oxidation of the metal anode in the presence of either aqueous or non-aqueous electrolyte. The electrolyte is used for transferring ions between the cathode and anode. In some cases, the electrolyte may also be used for washing away the products of the reaction (i.e., the metal's oxides) which coat the anode, thus allowing the oxidation reaction of the anode to continue and the battery to supply electricity.

Metal-air batteries have potentially high capacity, which make them attractive for use in electric vehicles. However, metal-air batteries known in the art still lack sufficient power to operate as a sole power supplier to electric vehicles.

Conventional batteries used in electric vehicles, for example, lithium based batteries, are large, expensive and have a limited energy source that needs to be recharged regularly, thus limiting the traveling range of the electric vehicles. At optimum driving conditions and without using the electric energy stored in the lithium based battery for any purposes other than driving the car, the maximum traveling range of the Tesla Roadster® was 394 km per charge, using a relatively large and very expensive lithium based battery. Any use of the electricity stored in the battery for heating or cooling the vehicle's passenger cabin, will reduce the traveling range dramatically.

A metal-air battery may be combined with a conventional lithium based battery to extend the traveling range of the electric vehicle when in need (acting like a reserve energy unit). Such a metal-air battery may include a tank for holding a reservoir of electrolyte for circulating the electrolyte in the battery, thereby slowing down the electrolyte's degradation.

SUMMARY OF THE INVENTION

Some embodiments of the invention may be related to a system and a method for heating a passengers' cabin in an electric vehicle, wherein the vehicle may be primarily powered by a main battery. The system may include a supplementary battery being metal-air battery including an electrolyte, for extending the travel range of the electric vehicle and a reservoir tank for holding an electrolyte volume for the metal-air battery, the electrolyte may be heated to a desired temperature. The system may further include a heat exchanger for conveying heat from the electrolyte volume, said heat is conveyable to said passenger's cabin.

Some additional aspects of the invention may be related to a system and method for heating components in electric vehicles. The electric vehicle is being powered by a main battery. The system may include a tank for holding heat accumulating liquid volume, the heat accumulating liquid may be heatable to a desired temperature, for example, 30-130° C. or 55-95° C., and a heat exchanger for conveying heat from the heat accumulating liquid, the heat may be conveyable to said components in said electric vehicle.

A tank holding heated heat accumulating liquid may be used as a thermal battery for holding reservoir of heat. The heat accumulating liquid may be heated during non-traveling periods of the vehicle (e.g., parking at the owner's garage and/or parking in public parking places) by, for example, plugging a heating element, installed at or proximal to the tank, to the city grid for heating the heat accumulating liquid. Additionally or alternatively, the tank may be filled/refilled with heated heat accumulating liquid from reservoirs of heated heat accumulating liquid, for example, in a gasoline/service station or at a public parking place, in order to enable fast loading of heat energy into the tank.

DETAILED DESCRIPTION OF THE INVENTION

One known source of electric power for an electric vehicle is a lithium-based battery, which has many benefits. Yet, the specific cost of a residual energy unit (e.g., KWh) stored in a lithium-based battery is relatively high. Some aspects of the invention may be related to a system for extending the traveling range of an electric vehicle (e.g., an electric car) by adding a supplementary, metal-air, battery having a relatively low specific cost of energy unit, to an (existing) main rechargeable lithium-based battery.

The metal-air battery may be used for recharging the main battery when needed, for example during traveling, when the capacity of the main battery drops below a predetermined threshold value; for example, bellow 70% of its full capacity. This arrangement may allow to use a relatively smaller and less expensive main rechargeable batteries, to fully power the vehicle during an average day-to-day travel need, for example, a 60 Km drive range between one recharging point, e.g. a user's home to the next recharging location, e.g., his/hers working place. When a longer traveling range is required the supplementary metal-air battery may be used to recharge the main rechargeable battery during the voyage. A first portion of the voyage may be powered solely by the main rechargeable battery until the capacity of the main battery drops below a predetermined threshold value, and then the supplementary metal-air battery may be activated to recharge the main battery, in a second portion of the voyage. In non-limiting exemplary embodiment, in a first 60 KM of the travel, the vehicle's electric motor may be powered solely by a main lithium based battery, and in an additional 300 KM, the electric motor may be powered from the lithium battery as the lithium based battery is recharged, during voyage, by a supplementary aluminum-air battery.

A reservoir tank for holding electrolyte volume may be assembled in the electric vehicle, for supplying electrolyte to the metal-air battery. A pump for circulating the electrolyte between the reservoir tank and the metal-air battery cell may also be assembled in the electric vehicle. In some embodiments, the volume of the electrolyte in the tank may be in the range of 10-1000 liters, for example, 20-50 liters for small electric car or 50-250 for an electric bus, electric boat or larger vehicles, such as ships, airplanes or the like.

This electrolyte volume may be used as a thermal battery for preserving heat, for example, for heating the vehicles' passenger cabin or other components of the electric vehicle such as the driver's seat or the main battery (e.g., the lithium battery). The electrolyte in the tank may be pre-heated (e.g., before the vehicle is started, when parked, etc.) by a heating element powered by an external electric source, for example, the city electricity grid. The city electricity grid is the cheapest among the three electric sources—lithium-based battery, metal-air battery and grid power. The heating element may be located anywhere in or near the electrolyte piping system for example in or near the reservoir tank. Additionally or alternatively, the electrolyte may be heated during the operation of the metal-air battery due to the exothermic reaction taking place on the surface of the metal anode in the metal-air battery. The heat from the oxidation of the anode is transferred into the electrolyte. As the reaction proceeds, the temperature of the electrolyte increases, and there may be a need to evacuate the heat from the electrolyte in order to keep the electrolyte, and thus the metal air battery, in working temperature range.

The pre-heated electrolyte may allow a better operation of the metal-air battery. The metal air battery may operate at optimal conditions when the electrolyte in the battery has a temperature between 30-100° C. In conventional operation of metal-air batteries, an exothermic reaction that occurs in the battery functions as the heat source, heating the electrolyte to the optimal temperatures. This process, however, may require some time and may decrease the ability of the battery to generate a required amount of power at the beginning of the battery operation, before it reaches optimal temperature. Therefore, in some embodiments, pre-heating the electrolyte in the reservoir to a desired temperature prior to the introduction of the electrolyte to the battery may result in allowing the air-metal battery to start working in optimal condition.

The heat from the heated electrolyte may be used in certain uses requiring heat-source. For example, heat from the heated electrolyte (e.g., excess heat) may be conveyed via a heat exchanger to the passenger's cabin to heat the cabin. This process may be particularly beneficial in cold weather places and/or during winter time, for example, in Northern Europe, North America, Japan, or the like. In conventional electric vehicles, the main electrical energy source (e.g., a lithium battery), which is comparatively rather expensive, is used for both traveling and cabin comfort (e.g., heat). Thus using the heat energy from the heated electrolyte, according to some embodiments of the invention, may save energy provided by the main energy source for traveling range.

In additional or alternative embodiments, the passengers' cabin or other components of the electric car may be heated using a system that includes a tank for holding heat accumulating liquid. Heat accumulating liquid may be any liquid that is capable of holding and preserving heat at a desired temperature, for example, water, mineral oils, solutions such as potassium hydroxide and sodium hydroide. The heat accumulating liquid may be heated inside the holding tank, for example, by a heating element located in the tank and powered by an external power source, for example, an electric grid. Additionally or alternatively, the tank may be filled with a heated heat accumulating liquid from a heated reservoir external to the vehicle, for example, a heated reservoir located at a service station. The heat from the heated heat accumulating liquid may be evacuated and conveyed to a component of the electric vehicle using a heat exchanger.

Reference is made toFIG. 1A, which is a schematic block diagram of system10for heating a component in an electric vehicle, for example, a passengers' cabin in an electric vehicle, according to some embodiments of the present invention. System10may provide heat to heat component20(e.g., a passengers' cabin) located in the electric vehicle. System10may comprise electric motor11, main rechargeable battery12for primarily powering the electric vehicle, supplementary metal-air battery14, reservoir tank16for holding electrolyte volume17, and heat exchanger19. Electrolyte17may be circulated between supplementary battery14and reservoir tank16by pump15. In some embodiments, reservoir tank16may include a heating element18for heating electrolyte17in tank16.

Main battery12may be any commercial rechargeable battery suitable for use in an electric vehicle. Main battery12may have enough power and enough power operating flexibility so as to provide a varying power buffer according to a the travel varying demand. For example, main battery12may be a lithium based battery (e.g., lithium-ion, lithium iron phosphate or lithium-titanate), lead acid battery, nickel metal hydride (NiMH) battery, nickel iron battery or the like.

Supplementary metal-air battery14may be electrically coupled to main battery12and may be activated to recharge main battery12during voyage of the electric vehicle, when the capacity of main battery12is below a predetermined threshold value, for example, below 70% of battery12full capacity. Supplementary metal-air battery14may include a metal anode made of one or more materials including, for example, aluminum, zinc, lithium, beryllium, calcium, or the like. Supplementary metal-air battery14may further include an air cathode that supplies oxygen from the surrounding air via a membrane (e.g., carbon membrane) that allows the oxygen to enter the cell. The battery further includes electrolyte that may be in a liquid phase or as a gel. An aqueous electrolyte may include salts such as KOH or NaOH having good ionic conductivity in an aqueous solution and forming an alkali solution.

Reservoir tank16may be any tank configured to hold, for example, 10-1000 liters of electrolyte17. In some embodiments, pump15may circulate electrolyte17between reservoir tank16and supplementary air-metal battery14. The circulation may be done to decrease the degradation of the electrolyte in supplementary air-metal battery14during the activation and operation of the battery. The electrolyte degradation is due to solid metal-oxide particles and metal hydroxide ions formed of the surface of the metallic anode during the oxidation reaction and solute into the electrolyte. During the operation of air-metal battery14, the oxidation reaction of the anode may form heat (i.e., the reaction is an exothermic reaction). The circulation of electrolyte17may allow conveying the heat away from the surface of the anode, thus allowing maintaining working operation conditions. In some embodiments, tank16may be insulated from its surroundings.

Working operation conditions of supplementary air-metal battery14, according to some embodiments of the invention, may depend on the temperature. For example, for an aluminum-air battery, the working temperature range is between 10-100° C. and, for example, 40-90° C. An aluminum air cell normally operates at a voltage of 0.9-1.3 volts. For a given temperature, increasing current draw decreases cell voltage and increases corrosion, and decreasing current draw increases voltage and increases corrosion.

In some embodiments, reservoir tank16may be used as a thermal battery for storing heat in electrolyte17. Electrolyte17may be heated to a desired temperature, for example, above 55° C. Tank16may further include at least one heating element18located inside tank16(as illustrated), at the vicinity of tank16and/or near a piping system adapted for circulating the electrolyte, for heating electrolyte17, using an external electric source. Heating element18may be powered by an electric source external to metal air battery14, for example, an electric source external to the electric vehicle. An example for an electric sources external to the metal air battery may be main battery12or an electric grid external to the electric vehicle. Heating element18may be powered and may heat electrolyte17during the recharging of the main battery12from the electric grid when the vehicle is parked. Additionally or alternatively, electrolyte17may be heated to the desired temperature due to the exothermic reaction that takes place in supplementary metal-air battery14. In some embodiments, heating element18may heat electrolyte17to store heat energy in the electrolyte reservoir tank. In some embodiments, electrolyte17may be heated to a temperature value in the recommended temperature range supplementary.

Storing of heat energy that was supplied from the electricity grid for purposes such as heating the passenger's cabin is less expensive compared to heating the cabin by energy drawn from the main or supplementary batteries. This arrangement is especially suitable for vehicles used in cold places.

Additionally or alternatively, electrolyte17may be heated in a reservoir or tank located externally to the electric vehicle, for example, in a service station designated for filling heated electrolyte17into tank16. In some embodiments, system10may include a replacement system (not illustrated) to replace the electrolyte when the temperature of the electrolyte16currently in the tank17, drops below a predetermined threshold value, for example, below the temperature of the electrolyte of the service station or at any given time. The replacement system may be configured to connect to a connector included in the service station. The replacement system may include a pipe connecting resrviour17and a replacement connector to be connected to the service station connector. The electric vehicle may stop at the station, and the electrolyte currently in the tank may be replaced with new, fresh electrolyte already heated to the desired temperature.

The heat stored in electrolyte17may be conveyed from reservoir tank16to component20included in the electric vehicle, for example, passengers' cabin, by heat exchanger19. Heat exchanger19may be any heat exchanger that is configured to convey heat from a heated liquid. For example, heat exchanger19may include two sets of pipes: a first set for heated electrolyte17, and a second set holding a liquid to which the heat from electrolyte17is to be conveyed. The heat may be conveyable to the passenger's cabin or any other component20included in the electric vehicle that needs to be heated.

System10may further comprise controller22that may be in active communication with one or more of electric motor11, main battery12, supplementary battery14, reservoir tank16, pump15, heat exchanger19and passenger's cabin20. Controller22may receive signals indicative of the working status/condition of the respective unit. Controller22may be configured to process the received signals according to a program or programs that may be stored in a non-transitory memory connected with controller22(not shown) and may be executed to carry out methods and operations according to embodiments of the present invention. Controller22may further be equipped with or in active communication with in/out (I/O) interface unit (not shown) that may enable controller22to read received signals and to issue control commands. Controller22may be configured to control one or more of electric motor11, main battery12, supplementary battery14, reservoir tank16, heat exchanger19, pump15, and passenger's cabin20to operate according to embodiments of the present invention.

Reference is made toFIG. 1Bwhich is a schematic block diagram of a system100for heating one or more components of an electric vehicle according to some embodiments of the invention. System100may be assembled in the electric vehicle and may include a tank116for holding a heat accumulating liquid volume117and a heat exchanger119for conveying heat from heat accumulating liquid117to one or more components in said electric vehicle. The one or more components may be, for example, passengers' cabin120, driver's seat130and/or a main battery140powering the electric vehicle. System100may further include a pump115for circulating heat accumulating liquid117. In some embodiments, system100may further include heating element118for heating heat accumulating liquid117.

Tank116may be any tank configured to hold liquids at a desired temperature, for example, at 55° C. Tank116may be insulated from its surroundings using any suitable insulating material. Tank116may be coated with insulating coating (e.g., a polymeric coating) or may be located inside an insulating housing for insulating the tank from the surroundings. The insulating housing may include an insulating material attached to the housing walls. Tank116inner walls may include or may be coated by a corrosion resistance material for protecting the inner portion of the tank from corrosion, due to the presence of heat accumulating liquid117.

Heat accumulating liquid117may be any liquid configured to accumulate heat. Heat accumulating liquid117may be: an electrolyte usable in a metal-air battery, water or an aqueous solution, oil or oil based solution or any other liquid. Some exemplary heat accumulating liquids may include: Ethylen glycol, propylene glycol, diethyl glycol, Betaine, propane diol, perfluorpolyether, salts, ionic liquids, solid particles such as TiO2, nano particles, Al2O3.

Tank116may include at least one heating element118located inside tank116(as illustrated), at the vicinity of tank116and/or near a piping system adapted for circulating heat accumulating liquid117. For example, heating element118may be powered by an electric source external to the electric vehicle, for example from an electric grid. Heating element118may be powered and may heat electrolyte117during the recharging of main battery140from the electric grid, when the vehicle is parked. Additionally or alternatively, heat accumulating liquid117may be heated in a reservoir located externally to the electric vehicle, for example, in a service station designated for filling heat accumulating liquid117into tank116. In some embodiments, the system may include a replacement system (not illustrated) to replace the heat accumulating liquid when the temperature of the heat accumulating liquid currently in the tank, drops below a predetermined threshold value, for example, below the temperature of the electrolyte of the service station or at any given time. The replacement system may be configured to connect to a connector included in the service station. The replacement system may include a pipe connecting tank117and a replacement connector to be connected to the service satation connector. The electric vehicle may stop at the station, and the heat accumulating liquid currently in the tank may be replaced with new, heat accumulating liquid already heated to a desired temperature.

The heat stored in heat accumulating liquid117may be evacuated from the liquid using heat exchanger119. Heat exchanger119may be any heat exchanger that is configured to convey heat from a heated liquid. For example, heat exchanger119may include two sets of pipes: a first set for the heated heat accumulating liquid117, and a second set holding a liquid to which the heat from heat accumulating liquid117is to be conveyed. In some embodiments, system100may include a pump115for circulating heat accumulating liquid117from tank116to heat exchanger119.

Heat exchanger119may convey heat to at least one component included in the electric vehicle. For example, the heat may be conveyed to heat passengers' cabin120and/or driver's seat130. In some embodiments, tank116may be located below driver's seat130, conveying heat directly to seat130. In some embodiments, the heat may be conveyed to heat main battery140. Main battery140may be any commercial rechargeable battery suitable for use in an electric vehicle. Main battery140may have enough power and enough power operating flexibility so as to provide a varying power buffer according to a driver's demand. For example, main battery140may be lithium based battery (e.g., lithium-ion, lithium iron phosphate or lithium-titanate), lead acid battery, nickel metal hydride (NiMH) battery, nickel iron battery or the like. Main battery140may have an optimal working temperature range, for example, 30-100° C. for lithium based battery. The heat may be conveyed to heat main battery140to a temperature in the optimal working temperature range.

System100may further comprise controller110that may be in active communication with one or more of liquid tank116, heat exchanger119, passenger's cabin120, driver's seat130, pump115, and main battery140. Controller110may receive signals indicative of the working status/condition of the respective units. Controller110may be configured to process the received signals according to a program or programs that may be stored in a non-transitory memory connected with controller110(not shown) and may be executed to carry out methods and operations according to embodiments of the present invention. Controller110may further be equipped with or in active communication with in/out (I/O) interface unit (not shown) that may enable controller110to read received signals and to issue control commands. Controller110may be configured to control one or more of liquid tank116, heat exchanger119, passenger's cabin120, driver's seat130, pump115, and main battery140to operate according to embodiments of the present invention.

In some embodiments, systems10and100may each include an additional controller. The additional controller or controllers22and110may control the operation of heating elements18or118and/or pumps15or115. The additional controller or controllers22and110may further control one or more valves configure to control the flow of the heated liquid or heated electrolyte to heat one or more components of the electric vehicle (e.g., main battery12or140, passengers' cabin20or120and driver's seat130). The additional controller or controllers22and110may control the liquid or electrolyte flow rate in various pipes included in the system according to a desired temperature at each of the components. The additional controller or controllers10and110may further control the operation of the heating element, to heat and maintain the temperature of the liquid or the electrolyte in the tank at the desired temperature.

In some embodiments, the desired temperature may be received from a user or may be determined based on the surrounding temperature, measured by a vehicle's thermometer. In some embodiments, the desired temperature and/or the flow rate of the liquid or the electrolyte may be determined based on information regarding a foreseen temperature received, for example, from a weather forecast. The information may be received by the controller via wireless communication. In some embodiments, the desired temperature may be between 30-130° C., 55-95° C., at least 30° C., at least 55° C. or more.

Some embodiments of the invention may be related to a service station for supplying a heated heat accumulating liquid or a heated electrolyte to an electric vehicle. The electric vehicle may be powered by a battery (e.g., battery12) and/or include a metal air battery (e.g., battery14). The service station may include a first tank for holding a heated heat accumulating liquid (e.g., liquid116) or a heated fresh electrolyte (e.g., electrolyte16). A heating element any be located inside the first tank to heat the heat accumulating liquid or electrolyte to a desired temperature, for example, a temperature between 30-130° C., 55-95° C. or the like. In some embodiments, a thermometer may be located inside the first tank to measure the temperature of the heat accumulating liquid or the heated electrolyte.

In some embodiments, the service station may further include a second tank for holding a used heat accumulating liquid or a used electrolyte. In some embodiments, the service station may further include a controller configured to control the replacement of the used heat accumulating liquid or the used electrolyte with the heated heat accumulating liquid or heated electrolyte. In some embodiments, the controller may further control the heating element to heat the liquid held in the first tank to the desired temperature according to reading received from the thermometer.

In some embodiments, the service satation may further include a connector to be connected to the electric vehicle for replacing the used heat accumulating liquid or the used electrolyte in the electric vehicle with the heated heat accumulating liquid or the heated electrolyte. In some embodiments, the service station may include a pump or any other pumping system for pumping the used liquid or used electrolyte from the vehicle's tank (e.g., tank17or tank117) via the connector to the second tank and further to pump the heated liquid from the first tank to be inserted into the vehicle's tank via the connector. The pump or pumping system may be controlled by the controller. The service station may be stationary or mobile. The service satation may serve more than one vehicle or more than one metal-air batteries included in a single vehicle, simultaneously. When an electric vehicle enters the service station, or when the service station reaches the electric vehicle, the replacement system may be connected to the service station via the connector.

Reference is now made toFIG. 2A, which is a flowchart depicting a method of heating a component in an electric vehicle, for example, passengers' cabin according to some embodiments of the invention. The electric vehicle may be powered by a main battery (e.g., battery12) such as a lithium-based battery, and a supplementary metal-air battery (e.g., battery14) such that the metal-air battery may provide electrical power to the main battery when needed, for example when its capacity drops below a definable threshold value for extending the travel range of the electric vehicle.

In block25, the method may include heating a reservoir tank comprising electrolyte volume usable in the metal-air battery. The electrolyte in the tank may be heated to a desired temperature, for example, above 70° C. In some embodiments, heating the reservoir tank may be done by powering a heating element located in the reservoir tank or in proximity to the reservoir tank or near the electrolyte piping system. The heating element may be powered from an external electric source, for example, an electric grid. In some embodiments, the heating element may be powered during charging of the main battery from an external electric source, for example, the electric grid, when the electric vehicle is parking. In some embodiments, the method may include activating the metal-air battery for charging the main battery during voyage of the electric vehicle, when the capacity of the main battery is below a predetermined threshold value. During the operation of the metal-air battery, the electrolyte in the tank reservoir tank may be heated by an exothermic reaction takes place in the air-metal battery.

In block30, the method may include evacuating heat from the heated electrolyte using a heat-exchanger, for example, heat exchanger19. In block35, the method may include conveying the heat to the passengers' cabin using a pipe system, for example, a pipe system included in heat exchanger19, the heat may be conveyable to the passenger's cabin, for example, cabin20.

Reference is now made toFIG. 2Bwhich is a flowchart depicting a method of heating a component in an electric vehicle according to some embodiments of the invention. The motor of the electric vehicle is being powered by a main battery (e.g., battery140or12). In block225, the method may include acquiring heat accumulating liquid, the accumulating liquid may heated to a desired temperature, for example, to 50° C.-90° C. The heat accumulating liquid may be held in a tank included in the electric vehicle. In some embodiments, acquiring heat accumulating liquid may include heating the heat accumulating liquid in the tank using a heating element powered by an electric source external to the electric vehicle, for example, the electric grid.

In some embodiments, acquiring heat accumulating liquid may include filling a heated heat accumulating liquid from an external reservoir, external to the electric vehicle, for example, a reservoir located in a filling station (e.g., a gasoline/service station). The electric car may stop at the station and the heat accumulating liquid currently in the tank may be replaced with a new heat accumulating liquid heated to a desired temperature. The heat accumulating liquid may be replaced when the temperature of the heat accumulating liquid currently in the tank, drops below a predetermined threshold value, for example, below 30° C.

In block230, the method may include evacuating heat from the heated heat accumulating liquid using a heat-exchanger, for example, heat exchanger19or119. In block235, the method may include conveying the heat to at least one component included in the electric vehicle. The at least one component may be the passengers' cabin, the driver's seat and/or the main battery.