Patent Description:
A metal air battery includes an anode that absorbs and emit ions and a cathode that uses oxygen from the air as an active material. In the cathode, reduction and oxidation of oxygen introduced from the outside occurs. In the anode, oxidation and reduction of a metal occurs. The chemical energy generated by the reactions is converted into electrical energy and extracted. For example, a metal air battery absorbs oxygen during discharge and discharges oxygen during charge. Since the metal air battery uses oxygen present in the air, the energy density of the battery may be greatly improved. For example, a metal air battery may have an energy density which is several times greater than a lithium ion battery.

In the metal air battery, the cathode may serve as an electron transfer path and an ion transfer path. Therefore, the capacity and performance of the metal air battery may be influenced by, for example, the material and configuration of the cathode (air electrode). When the metal air battery is a solid metal air battery including a solid electrolyte, a decrease in a reaction rate may occur due to decreased metal ion conductivity and electron conductivity, and increased interface resistance between the cathode and the solid electrolyte.

<CIT> discloses an air manager system for a metal-air battery. The air manager system recirculates reactant air to act as input ambient air for the metal-air battery, replacing oxygen using an oxygen generator. In an example, the recirculated air is controlled to maintain a humidity level, using a humidity monitor and a humidifier.

<CIT> discloses a metal-air cell charging apparatus. A humidified air generation and exhaustion unit generates and provides humidified air to a metal air cell.

<CIT> discloses a metal air battery in which an air purification module is configured to absorb an impurity (such as water) in supply air, and provide this supply air to a battery cell module.

According to an aspect of an embodiment, there is a metal air battery according to claim <NUM>. The battery module may include: an anode including a metal; a cathode configured to use the oxygen and the water vapor as an active material; and a solid electrolyte layer between the cathode and the anode.

The metal air battery may further include: an air purification module configured to purify air introduced from an outside of the battery module and supply the purified air to the water vapor supply unit.

The vapor supply unit is configured to supply the purified air and the water vapor to the battery module.

The water vapor recovery unit is configured to transfer the air from which vapor is removed to the air purification module, and wherein the water vapor supply unit is configured to supply the purified air and the water vapor to the battery module.

The metal air battery may further include: a first fluid regulator configured to regulate fluid communication between the water vapor supplied from the water vapor supply unit and the battery module.

The metal air battery may further include: a water vapor concentration measuring unit configured to measure a water vapor concentration of an inside of the battery module; and a controller configured to open and close the first fluid regulator according to the water vapor concentration of the inside of the battery module.

The metal air battery may further include: a second fluid regulator configured to regulate fluid communication between the water vapor recovered from the battery module and the water vapor recovery unit.

The metal air battery may further include: a water vapor concentration measuring unit configured to measure a water vapor concentration of an inside of the battery module; and a controller configured to open and close the second fluid regulator according to the water vapor concentration of the inside of the battery module.

The metal air battery may further include: a pump configured to apply a negative pressure to the battery module to recover the water vapor from the battery module.

The metal air battery may further include: a third fluid regulator configured to regulate a flow of the purified air supplied from the air purification module to the water vapor supply unit.

The metal air battery may further include: an oxygen concentration measuring unit configured to measure an oxygen concentration of an inside of the battery module; and a controller configured to open and close the third fluid regulator according to the oxygen concentration of an inside of the battery module.

The air purification module may operate by pressure swing adsorption (PSA), thermal swing adsorption (TSA), pressure thermal swing adsorption (PTSA), vacuum swing adsorption, or selective separation, or a combination thereof.

The vapor supply unit and the water vapor recovery unit may be in fluid communication with each other and are configured such that the water vapor recovered from the water vapor recovery unit may be transferred to the water vapor supply unit.

According to an aspect of another embodiment, there is a method of operating a metal air battery according to claim <NUM>.

The battery module may include: an anode including a metal; a cathode configured to use the oxygen and the water as an active material; and a solid electrolyte layer between the cathode and the anode.

The method may further include: measuring a water vapor concentration of an inside of the battery module during a discharge of the metal air battery; using a first fluid regulator configured to control flow of the vapor from the water vapor supply unit to the battery module according to the water vapor concentration of the inside of the battery module.

A second fluid regulator may be used to regulate flow of the water vapor recovered from the battery module to the water vapor recovery unit at a predetermined time interval, or to discharge the water vapor to an outside of the battery module at a predetermined time interval.

The method may further include: measuring a water vapor concentration of an inside of the battery module during charge of the metal air battery; and using a second fluid regulator to regulate flow of the water vapor from the battery module to the water vapor recovery unit according to the water vapor concentration of the inside of the battery module.

A pressure of the inside of the battery module is maintained by providing dry oxygen to the air purification module at a predetermined time interval, or providing dry air from the vapor recovery unit to the air purification module at a predetermined time interval.

The method may further include: measuring an oxygen concentration of an inside of the battery module during a discharge of the metal air battery; and using a third fluid regulator to regulate flow of the purified air supplied from the air purification module to the battery module according to the oxygen concentration of the inside of the battery module.

A second fluid regulator may be configured to regulate the flow of the purified air recovered from the battery module to the water vapor recovery unit at a predetermined time interval, or discharge of the purified air to an outside of the battery module at a predetermined time interval.

The method may further include: measuring a water vapor concentration of an inside of the battery module during a charge of the metal air battery; and applying a negative pressure to the battery module to transfer the water vapor from the battery module to the water vapor recovery unit.

A water and air handling system for a metal air battery includes: a water vapor supply unit configured to supply water vapor to the metal air battery; a water vapor recovery unit configured to recover the water vapor from the metal air battery; and an air purification module configured to purify air and supply the purified air to the water vapor supply unit.

A method of operating the water and air handling system includes removing an impurity from air supplied to the air purification module to prepare a purified air; supplying the purified air to a water vapor supply unit to remove water vapor from the purified air and prepare dry purified air; supplying the dry purified air and the water vapor to a metal air battery; and recovering the water vapor from the battery module using the water vapor recovery unit.

As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms, including "at least one," unless the content clearly indicates otherwise.

For example, a region illustrated or described as flat may have rough and/or nonlinear features.

Hereinafter, a metal air battery and an air handling system for a metal air battery according to embodiments will be described in detail with reference to the accompanying drawings. The width and thickness of the layers or regions illustrated in the accompanying drawings may be somewhat exaggerated for clarity and ease of description. Like reference numerals designate like elements throughout the specification.

As used herein, the terms "vapor" and "water vapor" may be used interchangeably, and each refer to a dispersion of water molecules, which are dispersed in the air.

As used herein, the term "dry air" refers to air which is substantially free of any water vapor (moisture). For example, the air may contain less than <NUM>% of water, or <NUM>% of water vapor, or less than <NUM>% water vapor, or less than <NUM>% water vapor, or less than <NUM>% water vapor. For example, the air may contain substantially <NUM>% water vapor.

<FIG> is a block diagram showing a schematic configuration of a metal air battery <NUM> according to an embodiment. <FIG> is a schematic view of a cell <NUM> in the battery module <NUM> shown in <FIG>. <FIG> is a block diagram showing a schematic configuration of the metal air battery <NUM> according to another embodiment.

Referring to <FIG>, the metal air battery <NUM> according to an embodiment may include a battery module <NUM>, a water vapor supply/recovery unit <NUM> including a water vapor supply unit <NUM>, and a water vapor recovery unit <NUM>, and an air purification module <NUM>. The battery module <NUM> may include a plurality of cells <NUM> and may generate electricity through the oxidation of metal and the reduction of oxygen and water vapor. The cell <NUM> according to an example may include an anode <NUM>, a cathode <NUM>, a solid electrolyte layer <NUM>, and a anode electrolyte layer <NUM>.

The anode <NUM> may include a material capable of absorbing and emitting (desorbing) metal ions. Such a material may include, for example, lithium (Li), sodium (Na), zinc (Zn), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), aluminum (Al), an alloy thereof, or a combination thereof. For example, the anode <NUM> may include lithium (Li). In this case, the anode <NUM> may include lithium, a lithium-based alloy, a lithium intercalating compound, or a combination thereof. When the anode <NUM> includes lithium, the metal air battery <NUM> according to the present embodiment may be referred to as a "lithium air battery".

The cathode <NUM> may be an electrode using oxygen O<NUM> and water vapor (H<NUM>O) present in the air as an active material. For the electrochemical reaction between metal ions provided from the anode <NUM> and the gas (i.e., oxygen) and water vapor provided to the cathode <NUM>, the cathode <NUM> may provide a movement path for metal ions and a movement path for electrons.

When the metal air battery <NUM> according to the present embodiment is the lithium air battery, the following electrochemical reaction shown in Equation <NUM> may occur in the cathode <NUM> during discharge.

2Li+ + <NUM>/2O<NUM> + H<NUM>O + 2e- ↔ 2LiOH     (<NUM>).

Lithium ions Li+ provided from the anode <NUM> and oxygen O<NUM> and water vapor provided from the atmosphere (air), may react together with electrons e- at a surface of the cathode <NUM> to generate lithium hydroxide LiOH. At this time, the cathode <NUM> may provide both a metal ion movement path of lithium ions Li+ and an electron movement path of electrons e-. The lithium hydroxide LiOH generated by the electrochemical reaction may be an example of a reaction product. Following charge, a discharge reaction may be reversely performed.

For example, the cathode <NUM> may include a composite conductive material capable of providing the movement paths of both lithium ions Li+ and electrons e-. To adjust a cation conductivity and an electron conductivity of the composite conductive material, a composition of the composite conductive material may be controlled by varying the components therein and/or by adding a dopant. Even when comparing composite conductive materials having the same composition, the cation conductivity and the electron conductivity may vary depending on the ratio of each material in the composite conductive material and the amount of dopant. The composite conductive material may include, for example, a lithium-based oxide, a sodium-based oxide, or a combination thereof.

The solid electrolyte layer <NUM> may provide a movement path for metal ions provided from the anode <NUM>. For example, the solid electrolyte layer <NUM> may include a composite conductive material capable of both electronic conduction and metal ion conduction. To adjust the cation conductivity and electron conductivity of the composite conductive material, the composition ratio or the dopant of the composite conductive material may be adjusted accordingly. Even in case of materials having the same composition, the cation conductivity and the electron conductivity may vary depending on the composition ratio and the dopant. The composite conductive material may include, for example, a lithium-based oxide, a sodium-based oxide, or a combination thereof.

As described above, the composite conductive material included in the cathode <NUM> and the solid electrolyte layer <NUM> may be an inorganic-based solid compound. Accordingly, the cathode <NUM> may be an electrode that does not include an organic electrolyte, that is, an organic electrolyte-free electrode. The solid electrolyte layer <NUM> may also be organic electrolyte-free. Also, the cathode <NUM> may be an electrode that does not include a liquid electrolyte, and thus may be a liquid electrolyte-free electrode.

The anode electrolyte layer <NUM> may include an ion conductive material to allow conduction of ions between the anode <NUM> and the cathode <NUM>. The anode electrolyte layer <NUM> may include a solid electrolyte (e.g., electrolyte having a solid phase). The solid electrolyte of the anode electrolyte layer <NUM> may include a polymer electrolyte, an inorganic electrolyte, or a composite electrolyte that is a mixture of the polymer electrolyte and the inorganic electrolyte. For example, the anode electrolyte layer <NUM> may include a polymeric nonwoven fabric such as a nonwoven fabric made of polypropylene, polyphenylene sulfide, or a combination thereof, a porous film including an olefin-based resin such as polyethylene or polypropylene, or a combination thereof. However, the specific material used for the solid electrolyte is not limited thereto and may be modified to include any suitable solid electrolyte material.

Although not shown in <FIG>, a gas diffusion layer that absorbs oxygen from ambient air and provides oxygen to the cathode <NUM> may be disposed on the cathode <NUM>. To this end, the gas diffusion layer may have a porous structure so as to smoothly diffuse oxygen. For example, the gas diffusion layer may be formed of a carbon paper, a carbon cloth, a carbon felt (e.g., carbon fiber), a sponge foam metal, a metal fiber mat, or a combination thereof. However, the cathode <NUM> may be manufactured to have a porous structure or a similar structure to serve as the gas diffusion layer. In this case, the gas diffusion layer may be omitted. In an alternative configuration, a cathode current collector may be disposed in contact with the gas diffusion layer and the anode current collector may be disposed in contact with the anode <NUM>. For example, the anode current collector may be regarded as a part of the anode <NUM>, and similarly, the cathode current collector may be regarded as a part of the cathode <NUM>.

The metal air battery <NUM> according to the present embodiment may be a liquid electrolyte-free battery that does not include a liquid electrolyte. Also, the metal air battery <NUM> according to the present embodiment may be an organic electrolyte-free battery which does not include an organic electrolyte. Thus, the metal air battery <NUM> may be organic electrolyte-free, liquid electrolyte-free, or a combination thereof.

When the cell <NUM> is a liquid electrolyte-free cell, and the metal air battery is a liquid electrolyte-free full solid metal air battery, a decreased reaction rate may occur due to relatively low levels of metal ion conductivity, low levels of electron conductivity, and a large interface resistance between the cathode <NUM> and the solid electrolyte layer <NUM>. To improve reaction rates and decrease resistance, an air intake system disposed in a metal air battery has been used to remove moisture. Meanwhile, in an embodiment, an additive, for example, water vapor, which is capable of improving the metal ion conductivity and the electron conductivity and reducing a surface resistance during a discharge process, is supplied to the full solid metal air battery. Also, water vapor generated during a charge process is recovered.

The vapor supply/recovery unit <NUM> may supply water vapor to the battery module <NUM> when the metal air battery <NUM> is discharged, and recover the water vapor from the battery module <NUM> when the metal air battery <NUM> is charged. For example, the vapor supply/recovery unit <NUM> may include a vapor supply unit <NUM> for supplying vapor to the battery module <NUM> and a vapor recovery unit <NUM> for recovering vapor from the battery module <NUM>. At this time, the vapor supply unit <NUM> and the vapor recovery unit <NUM> may be integrally formed as shown in <FIG> or may be separately formed as shown in <FIG>.

The vapor supply unit <NUM> is a supply device capable of supplying water vapor to the battery module <NUM> in order to improve the metal ion conductivity and the electron conductivity of the cathode <NUM> and reduce an interface resistance. For example, the vapor supply unit <NUM> may regulate a supply rate of the water vapor according to a charge/discharge rate of the metal air battery <NUM>.

Without being limited by theory, it is understood that the water vapor supplied through the vapor supply unit <NUM> may adhere to the surface of the cathode <NUM> to improve the metal ion conductivity and the electron conductivity and reduce the interface resistance. The water vapor supplied through the vapor supply unit <NUM> may react with the electrons e- at the surface of the cathode <NUM> together with oxygen O<NUM> supplied from atmospheric air during the discharge process to generate lithium hydroxide LiOH, or may decompose lithium hydroxide LiOH during the charge process and return to water vapor.

The vapor recovery unit <NUM> may recover excess water vapor present in the battery module <NUM>. For example, the vapor recovery unit <NUM> may be a vapor condenser, but is not limited thereto. According to an embodiment, the vapor supply unit <NUM> and the vapor recovery unit <NUM> may be in fluid communication with each other. At this time, the vapor recovery unit <NUM> may condense the water vapor recovered from the battery module <NUM> and deliver the water vapor to the vapor supply unit <NUM>. Also, according to an example, air from outside of the metal-air battery (also referred to herein as "external air") may be introduced into the vapor recovery unit <NUM>. At this time, the vapor recovery unit <NUM> may condense water vapor present in the outside air to remove the water vapor from the outside air.

The air purification module <NUM> may purify the air by removing impurities, such as water vapor, nitrogen (N<NUM>), and carbon dioxide (CO<NUM>), present in the air and supply the purified air to the battery module <NUM>. The air purification module <NUM> may be disposed in direct fluid communication with the battery module <NUM> or may be disposed in fluid communication with the battery module <NUM> via the vapor supply unit <NUM>. For example, when the vapor supply unit <NUM> and the vapor recovery unit <NUM> are integrally formed as shown in <FIG>, the external air may flow directly into the air purification module <NUM>. The air purification module <NUM> may remove impurities such as water vapor, nitrogen, and carbon dioxide from the air and supply purified air to the vapor supply/recovery unit <NUM>. Since the water vapor has been removed, the purified air is supplied as dry air. Also, when the vapor supply unit <NUM> and the vapor recovery unit <NUM> are separately formed as shown in <FIG>, the external air may flow into the vapor recovery unit <NUM> and may be dry air from which water vapor is removed. The air purification module <NUM> may remove impurities such as nitrogen, and carbon dioxide which may be present in the dry air.

The air purification module <NUM> may be configured to operate by pressure swing adsorption (PSA), thermal swing adsorption (TSA), pressure thermal swing adsorption (PTSA), vacuum swing adsorption, selective separation, or a combination thereof. As used herein, the term "PSA" means a technique in which a specific gas is preferentially adsorbed or captured on an adsorbent at high pressure and the specific gas is emitted or discharged when pressure is reduced. As used herein, the term "TSA" means a technique in which a specific gas is preferentially adsorbed or captured on an adsorbent at room temperature and the specific gas is emitted or discharged when the temperature increases. As used herein, the term "PTSA" means a technique including a combination of "PSA" and "TSA". As used herein, "VSA" means a technique in which a specific gas is preferentially adsorbed or captured on an adsorbent under approximate atmospheric pressure and the specific gas is emitted or discharged under vacuum. A more specific method of charging and discharging the metal air battery <NUM> according to an embodiment will be described with reference to <FIG>.

<FIG> is a flowchart illustrating a method of operating a metal air battery according to an example.

Referring to <FIG> and <FIG>, in operation S110, external air may be introduced into the air purification module <NUM>. The air purification module <NUM> may remove impurities present in the external air to purify the external air (purified external air). For example, the air purification module <NUM> may use pressure swing adsorption (PSA), thermal swing adsorption (TSA), pressure swing adsorption (PTSA), vacuum swing adsorption (VSA), selective separation, or a combination thereof, to remove impurities such as water vapor, nitrogen, and carbon dioxide from the external air and generate purified air A<NUM>. At this time, the purified air A<NUM> may be oxygen O<NUM> from which water vapor is removed (e.g., dry purified air).

In operation S120, the purified air A<NUM> may be supplied from the air purification module <NUM> to the vapor supply unit <NUM>. For example, when the purified air A<NUM> is supplied from the air purification module <NUM> to the vapor supply unit <NUM>, the purified air A<NUM> may be combined with water vapor to provide water vapor and purified air (H<NUM>O + O<NUM>); A<NUM> state. The water vapor is further supplied from the vapor supply unit <NUM> and the water vapor is added to the purified air.

In operation S130, the water vapor and the purified air A<NUM> may be supplied to the battery module <NUM> from the vapor supply unit <NUM>. For example, when the metal air battery <NUM> is discharged, the water vapor and the purified air A<NUM> may be supplied to the cathode <NUM>, which uses the water vapor and oxygen as an active material. At this time, as may be seen in the above-mentioned reaction Equation <NUM>, the metal air battery <NUM> may generate lithium hydroxide LiOH as a reaction product, and thereby generate electricity.

In operation S140, the water vapor may be recovered from the battery module <NUM> to the vapor recovery unit <NUM>. For example, when the metal air battery <NUM> is charged, as may be seen in reaction Equation <NUM>, the oxygen O<NUM> and the water vapor may be continuously generated by the cathode <NUM>, and thus an amount of the oxygen O<NUM> and the water vapor may increase in the battery module <NUM>. Therefore, when the metal air battery <NUM> is charged, the oxygen O<NUM> and the water vapor disposed in the battery module <NUM> may be appropriately released to the outside of the metal air battery depending upon the use conditions of the metal air battery <NUM> and/or the internal conditions of the battery module <NUM>.

According to an embodiment, the water vapor generated during charge of the metal air battery <NUM> may be recovered through the vapor recovery unit <NUM>. The water vapor H<NUM>O recovered by the vapor recovery unit <NUM> may be transferred to the vapor supply unit <NUM> and reused. The oxygen O<NUM> generated during charge of the metal air battery <NUM> may be discharged to the outside of the metal air battery through the battery module <NUM> or the vapor recovery unit <NUM>. As a result, the amount of the water vapor and oxygen O<NUM> inside of the battery module <NUM> may be controlled to prevent deterioration in the charging efficiency of the metal air battery. Since the air purification module <NUM> may supply purified air A<NUM>, accordingly, an internal pressure of the battery module <NUM> may be maintained over a predetermined range and the water vapor and oxygen O<NUM> may be discharged to the vapor recovery unit <NUM>.

<FIG> is a cross-sectional view illustrating a configuration of a metal air battery according to an Example. <FIG> is a cross-sectional view showing a configuration of a metal air battery according to a Comparative Example. <FIG> and <FIG> are respectively graphs showing experimental results of an electrochemical module for both the Example and the Comparative Example.

Referring to <FIG>, the metal air batteries according to the Example and the Comparative Example are coin type batteries. The components of the battery are provided in a case <NUM> including a plurality of opening areas H1. A support structure <NUM> may be provided on a lower surface of the case <NUM>. The support structure <NUM> may include, for example, a spacer and a spring member. An anode <NUM> including a metal may be provided on the support structure <NUM>. A reaction inhibiting layer <NUM> and the anode electrolyte layer <NUM> may be sequentially disposed on the anode <NUM>. The reaction inhibiting layer <NUM> is interposed between the anode <NUM> and the anode electrolyte layer <NUM> and may suppress/prevent a reaction therebetween. The reaction inhibiting layer <NUM> may have an ion conductive function.

The cathode <NUM> and the solid electrolyte layer <NUM> may be disposed on the anode electrolyte layer <NUM>. The cathode <NUM> and the solid electrolyte layer <NUM> may each have a structure including a plurality of pores. An electrically conductive material layer (hereinafter conductive layer) <NUM> may be provided on the cathode <NUM>. A gas diffusion layer <NUM> may be provided on the conductive layer <NUM>. In the Example, the gas diffusion layer <NUM> may be disposed adjacent to the plurality of opening areas H<NUM> and supplies the oxygen O<NUM> and the water vapor to the cathode <NUM>. In the Comparative Example, the gas diffusion layer <NUM> is disposed adjacent to the plurality of opening regions H<NUM> and supplies only dry oxygen O<NUM> to the cathode <NUM>.

For example, the anode <NUM> may include Li, the cathode <NUM> may include a lithium-lanthanum manganese oxide (LLMO), and the solid electrolyte <NUM> may include lithium aluminum titanium phosphate (LATP). The anode electrolyte layer <NUM> may further include <NUM> molar (M) lithium bis(trifluoromethanesulfonyl)imide/(poly (ethylene glycol) dimethyl ether)(LiTFSI/PEGDME). The conductive layer <NUM> may include Au. In the Example, the operating temperature of a battery included in the metal air battery <NUM> is set to <NUM> degrees Celsius (°C), and the oxygen O<NUM> and the water vapor are supplied such that the relative humidity is <NUM>%, and a charge/discharge cycle is performed at a constant current (CC) of <NUM> microampere per square centimeter (µA/cm<NUM>). In the comparative example, the battery included in the metal air battery is set to an operating temperature of <NUM>, dry oxygen O<NUM> is supplied to the cathode <NUM>, and a charge/discharge cycle is performed at the constant current of <NUM>µA/cm<NUM>.

As shown in <FIG>, a comparison of the Example where the oxygen O<NUM> and the vapor H<NUM>O are supplied such that the relative humidity becomes <NUM>% with the Comparative Example in which only the oxygen O<NUM> is supplied, it may be seen that a reaction voltage E<NUM> increases from <NUM> volts (V) (Comparative Example) to <NUM> V (Example), and the charge/discharge reproducibility and cyclability are improved. This means that a metal ion conductivity and an electron conductivity of the cathode <NUM> are improved and an interface resistance decreases. Therefore, the metal air battery <NUM> according to the embodiment in which the vapor H<NUM>O is added to the cathode <NUM> provided as a movement path for metal ions and electrons may be advantageous to improvement of the performance and increase of the lifespan of the battery.

Also, as shown in <FIG>, in the Example where the oxygen O<NUM> and the water vapor are supplied such that the relative humidity becomes <NUM>%, oxidation of the discharge product LiOH as well as the addition of oxidation products (oxygen and water vapor) after discharge results in deterioration of charge/discharge reproducibility and cyclability. Without being limited by theory, it is understood that the charge reproducibility is reduced by the presence of excess water vapor and oxygen generated in the cathode <NUM>. Therefore, during charge of the metal air battery <NUM>, removal of vapor and oxygen, which are discharge reaction products, from the battery module <NUM> according to internal conditions of the metal air battery <NUM>, may prevent deterioration in the charging efficiency of the metal air battery <NUM>. In addition, when the concentration of oxygen and water vapor supplied to the battery module <NUM> increases during discharge of the metal air battery <NUM>, deterioration in the discharging efficiency of the metal air battery <NUM> may also be prevented. Accordingly, to prevent the deterioration in the charge and discharge efficiency of the metal air battery, the flow of oxygen and water vapor supplied to the battery module and the flow of oxygen and vapor discharged from the battery module may be controlled.

<FIG> are block diagrams showing a schematic configuration of the metal air battery <NUM> according to another embodiment. <FIG> is a block diagram showing a schematic configuration of the metal air battery <NUM> according to yet another embodiment.

Referring to <FIG>, the metal air battery <NUM> according to an example may include the battery module <NUM>, the vapor supply unit <NUM>, the vapor recovery unit <NUM>, the air purification module <NUM>, a first fluid regulator <NUM>, a second fluid regulator <NUM>, a controller <NUM>, a third fluid regulator <NUM>, and a measuring unit <NUM>. Descriptions related to the battery module <NUM>, the vapor supply unit <NUM>, the vapor recovery unit <NUM>, and the air purification module <NUM> are substantially the same as previously described for <FIG>, and thus, the descriptions thereof will be omitted for convenience.

The first fluid regulator <NUM> is a flow modification device capable of regulating flow of the water vapor supplied from the vapor supply unit <NUM> to the battery module <NUM>. In other words, the first fluid regulator is configured to modulate fluid communication between the vapor supply unit and the For example, the first fluid regulator <NUM> may be disposed downstream of a discharge part of the vapor supply unit <NUM> to regulate the flow of water vapor supplied to the battery module <NUM>. During discharged of the metal air battery <NUM>, as shown in the above-mentioned reaction equation, water vapor may be supplied to the cathode <NUM> and a water molecule may be used as an anode active material.

For example, the first fluid regulator <NUM> may be an electronically driven open/close valve and may control a flow rate of water vapor supplied from the water vapor supply unit to the battery module <NUM> by controlling the opening/closing of the valve. The electronically driven open/close valve may be driven by, for example a solenoid, which is an electronic driving device, and may switch between interruption and release of the open/close valve by turning on/off a pulse shape excitation current transmitted to the solenoid. The discharge of water vapor from the vapor supply unit <NUM> may be controlled to have high precision and high responsiveness by the first fluid regulator <NUM>. The interruption and release timing of the electronically driven open/close valve is controlled by a control signal output from the controller <NUM> that will be described later.

The first fluid regulator <NUM> may change the opening area (opening degree) of the open/close valve and/or the opening time of the open/close valve, in order to control a flow of the water vapor discharged from the vapor supply unit <NUM>. For example, the first fluid regulator <NUM> may control the flow of the water vapor discharged from the vapor supply unit <NUM> by an interruption cycle, which repeatedly switches between a flow interruption time (closed valve) and a flow release time (open valve).

The second fluid regulator <NUM> is a flow modification device disposed between the battery module <NUM> and the vapor recovery unit <NUM>, and which is capable of regulating fluid communication between the battery module <NUM> and the vapor recovery unit <NUM>. For example, the second fluid regulator <NUM> may be formed as an electronically driven open/close valve and may control the opening/closing of the valve to facilitate flow of oxygen and/or water vapor from the battery module <NUM> to the vapor recovery unit <NUM> during a charge of the metal air battery <NUM>. The second fluid regulator <NUM> may also control the open/close valve to facilitate flow of a discharge product generated in the battery module <NUM> to the vapor recovery unit <NUM> during discharge of the metal air battery <NUM>.

For example, the second fluid regulator <NUM> may also change an opening area (opening degree) of the open/close valve and/or an opening time of the open/close valve in order to control the flow of discharge products, for example, water vapor and oxygen, discharged from the battery module <NUM>. For example, the second fluid regulator <NUM> may control the flow of oxygen and water vapor discharged from the battery module <NUM> by the interruption cycle which repeatedly switches between a glow interruption time and a flow release time.

Also, for another example, as shown in <FIG>, a pump <NUM> capable of recovering water vapor by applying a negative pressure to the battery module <NUM> may be disposed between the battery module <NUM> and the vapor recovery unit <NUM>. Accordingly, in the process of charging the metal air battery <NUM>, the pump <NUM> may operate to recover the water vapor and oxygen from the battery module <NUM>. The water vapor transferred to the vapor recovery unit <NUM> may be condensed and transferred to the vapor supply unit <NUM>, and the oxygen delivered to the vapor recovery unit <NUM> may be discharged to the outside.

The third fluid regulator <NUM> is a flow modification device capable of regulating a flow of purified air supplied from the air purification module <NUM> to the battery module <NUM>. For example, the third fluid regulator <NUM> may be disposed downstream of a discharge portion of the air purification module <NUM> to intercept (or facilitate) the flow of purified air supplied to the battery module <NUM>.

For example, the third fluid regulator <NUM> may be an electronically driven open/close valve and may control a flow rate of the purified air supplied to the battery module <NUM> by driving the opening/closing of the open/close valve. The discharge of the purified air from the air purification module <NUM> may be controlled with high precision and high responsiveness by the third fluid regulator <NUM>. The interruption and release timing of the electronically driven open/close valve is controlled by the control signal output from the controller <NUM> that will be described later.

The third fluid regulator <NUM> may change the opening area (opening degree) of the open/close valve and/or the opening time of the open/close valve, in order to control the flow of the purified air discharged from the air purification module <NUM>. For example, the third fluid regulator <NUM> may control the flow of the purified air discharged from the air purification module <NUM> by the interruption cycle, which repeatedly switches between a flow interruption time (closed valve) and a flow release time (open valve).

The controller <NUM> may be a device that controls the overall function and operation of the metal air battery <NUM>, and which is configured to store and execute a computer program. The controller <NUM> may execute a program stored in a memory (not shown) to control the first fluid regulator <NUM>, the second fluid regulator <NUM>, the third fluid regulator <NUM>, and/or the pump <NUM> according to a discharge state and a charge state of the metal air battery <NUM>. According to an example, the controller <NUM> may be implemented in the form of a single microprocessor module or a combination of two or more microprocessor modules. That is, the type of the controller <NUM> is not limited and may be any suitable device capable of storing and executing a program. For example, the controller <NUM> may be part of a battery management system (BMS).

The measuring unit <NUM> is configured to measure a status of the metal air battery <NUM> and then transmit information about the status to the controller <NUM>. Here, the status of the metal air battery <NUM> may include a voltage of the metal air battery, a charge amount of the metal air battery, an oxygen concentration or a water vapor concentration inside of the battery module <NUM>, or a combination thereof. To this end, the measuring unit <NUM> may include an oxygen concentration measuring unit <NUM>, a vapor concentration measuring unit <NUM>, or a combination thereof. However, the present disclosure is not limited thereto, and other status parameters that may affect the charge and discharge processes of the metal air battery <NUM> may also be measured.

<FIG> is a flowchart illustrating a method of operating a metal air battery during discharge of the metal air battery according to an embodiment. <FIG> is a flowchart illustrating a method of operating a metal air battery during charge of the metal air battery according to an embodiment.

Referring to <FIG> and <FIG>, in operation S210, external air may be introduced into the air purification module <NUM>. The air purification module <NUM> may remove impurities present in the external air to purify the external air. At this time, when the vapor supply unit <NUM> and the vapor recovery unit <NUM> are formed as separate structures, the external air may flow into the vapor recovery unit <NUM> and be discharged in a dry air state. Dry air may flow into the air purification module <NUM> and be discharged as the purified air A<NUM>.

In operation S220, the purified air A<NUM> may be supplied by the air purification module <NUM> to the vapor supply unit <NUM>. For example, the third fluid regulator <NUM> may open and close based upon a predetermined cycle in order to supply a suitable amount of the purified air A<NUM> from the air purification module <NUM> to the vapor supply unit <NUM>.

In operation S230, both water vapor and the purified air A<NUM> may be supplied to the battery module <NUM> from the vapor supply unit <NUM>.

For example, the open/close valve of the first fluid regulator <NUM> may open based on a predetermined cycle to supply a fluid, for example, water vapor and the purified air A<NUM>, discharged from the vapor supply unit <NUM> to the battery module <NUM>. At this time, the open/close valve of the second fluid regulator <NUM> may be closed in order to interrupt a flow of the fluid, for example, the water vapor and the purified air A<NUM> disposed in the battery module <NUM>, such that the fluid disposed in the battery module <NUM> may not be discharged to the outside. Alternatively, the open/close valve of the second fluid regulator <NUM> may be cycled between a closed and opened state in order to interrupt and release the flow of the fluid disposed in the battery module <NUM>, respectively, such that the fluid disposed in the battery module <NUM> may be discharged to the outside according to a predetermined time interval.

In operation S240, the oxygen concentration measuring unit <NUM> or the vapor concentration measuring unit <NUM> may measure an oxygen concentration or a water vapor concentration of an inside of the battery module <NUM> in a discharge state.

When the water vapor and the purified air A<NUM> are supplied from the vapor supply unit <NUM> and the air purification module <NUM>, respectively, to the battery module <NUM> to discharge the metal air battery <NUM>, the water vapor concentration and the oxygen concentration inside of the battery module <NUM> may change. At this time, the oxygen concentration measuring unit <NUM> or the water vapor concentration measuring unit <NUM> may measure a "current" (e.g., point in time) oxygen concentration or current water vapor concentration of the inside of the battery module <NUM>.

In operation S260, the controller <NUM> may control an operation of the first fluid regulator <NUM> or the third fluid regulator <NUM> according to the oxygen concentration or the water vapor concentration of the inside of the battery module <NUM>.

Information regarding the current oxygen concentration or vapor concentration of the inside of the battery module <NUM> may be transferred to the controller <NUM> by the oxygen concentration measuring unit <NUM> or the vapor concentration measuring unit <NUM>. For example, the controller <NUM> controls the operation of the third fluid regulator <NUM> by comparing a preset (stored) reference oxygen concentration to the current oxygen concentration of the inside of the battery module <NUM> received from the oxygen concentration measuring unit <NUM>. For example, when the oxygen concentration of the inside of the battery module <NUM> is less than the preset reference oxygen concentration, the interruption and release cycle of the third fluid regulator <NUM> may be adjusted such that a release time of the third fluid regulator <NUM> is increased.

Also, for example, the controller <NUM> controls the operation of the first fluid regulator <NUM> by comparing a preset (stored) reference vapor concentration to the current vapor concentration of the inside of the battery module <NUM> received from the vapor concentration measuring unit <NUM>. When the vapor concentration of the inside of the battery module <NUM> is less than the preset reference vapor concentration, the interruption and release cycle of the first fluid regulator <NUM> may be adjusted such that a release time of the first fluid regulator <NUM> is increased.

Referring to <FIG> and <FIG>, in operation S310, the water vapor may be recovered from the battery module <NUM> and transferred to the vapor recovery unit <NUM>. For example, when the metal air battery <NUM> is charged, as may be seen in the above-mentioned reaction equation <NUM>, the oxygen O<NUM> and the water vapor may be continuously generated from the cathode <NUM>, and thus, an amount of the oxygen O<NUM> and the water vapor may increase in the battery cell module <NUM>.

The first fluid regulator <NUM> may regulate a flow of water vapor and the purified air A<NUM> such that the water vapor and the purified air A<NUM> may be prevented from flowing into the battery module <NUM>. However, air which is not regulated first fluid regulator <NUM> may also be provided to the battery module to maintain pressure inside of the battery module <NUM> at a predetermined pressure, for example, as shown in <FIG>. As shown in <FIG>, the dry oxygen O<NUM> which has been purified by the removal of water vapor, nitrogen, and carbon dioxide from external air by the air purification module <NUM>, may be supplied directly to the battery module <NUM>; as shown in <FIG>, dry air from which only water vapor has been removed from external air by the vapor recovery unit <NUM>, may be supplied directly to the battery module <NUM>; or as shown in <FIG>, the external air may be directly supplied to the battery module <NUM> from outside of the battery.

In operation S320, the vapor concentration measuring unit <NUM> may measure a water vapor concentration of the inside of the battery module <NUM> in a charge state.

When the metal air battery <NUM> is charged, oxygen and water vapor may be generated in the cathode <NUM> during the charge process, and accordingly the water vapor concentration and the oxygen concentration on the inside of the battery module <NUM> may change. The vapor concentration measuring unit <NUM> may measure a current water vapor concentration of the inside of the battery module <NUM>. Although the current water vapor concentration of the inside of the battery module <NUM> may be measured in the present embodiment, the current oxygen concentration of the inside of the battery module <NUM> may also be measured using the oxygen concentration measuring unit <NUM>. For example, the measuring of the current water vapor concentration and the current oxygen concentration may occur at the same time.

In operation S330, the controller <NUM> may control operation of the second fluid regulator <NUM> according to the current water vapor concentration of the inside of the battery module <NUM>.

The information regarding the current water vapor concentration of the inside of the battery module <NUM> may be transferred to the controller <NUM> by the vapor concentration measuring unit <NUM>. For example, the controller <NUM> controls the operation of the second fluid regulator <NUM> by comparing a predetermined reference vapor concentration with the current vapor concentration of the inside of the battery module <NUM> transferred from the vapor concentration measuring unit <NUM>. For example, when the current water vapor concentration of the inside of the battery module <NUM> is greater than the reference vapor concentration, the interruption and release cycle of the second fluid regulator <NUM> may be adjusted such that a release time of the second fluid regulator <NUM> is increased. Also, as shown in <FIG>, when the pump <NUM> capable of applying negative pressure to the battery module <NUM> is disposed downstream of the second fluid regulator <NUM>, and the current water vapor concentration of the inside of the battery module <NUM> is greater than the reference vapor concentration, the controller <NUM> may operate the pump P to remove water vapor from the battery module <NUM>, thereby lowering the water vapor concentration of the inside of the battery module <NUM>. While the operation of the second fluid regulator <NUM> may be controlled according to the vapor concentration of the inside of the battery module <NUM>, the controller <NUM> may also control the operation of the second fluid regulator <NUM> by comparing a predetermined reference oxygen concentration with the current oxygen concentration of the inside of the battery module <NUM>.

According to the above-described embodiments, the metal air battery and the method of operating the metal air battery may include supply of water vapor to the anode during discharge of the metal air battery and recovery of the water vapor generated during charge of the metal air battery in order to control a water vapor concentration and adjust charge and discharge states, thereby preventing deterioration of the charge and discharge efficiency of the metal air battery. The metal air battery may be utilized as a power source in various electronic devices including electric vehicles. The metal air battery according to the embodiments may be applied to all fields in which a secondary battery is applied. Also, according to the above-described embodiments, the metal air battery and the method of operating the metal air battery may supply water vapor to improve a metal ion conductivity and an electron conductivity and reduce interface resistance.

Descriptions of features or aspects within each embodiment should be considered as available for other similar features or aspects in other embodiments.

Claim 1:
A metal air battery (<NUM>) comprising:
a battery module (<NUM>) configured to generate electricity by oxidation of a metal and reduction of oxygen and water;
a water vapor supply unit (<NUM>) configured to supply water vapor to the battery module during a discharging of the metal air battery; and
a water vapor recovery unit (<NUM>) configured to recover the water vapor generated by the battery module during a charging of the metal air battery.