Gas suppression device and suppression method for lithium-sulfur batteries

Abstract

A gas suppression device for a lithium-sulfur battery is provided, the device including: a voltage measurement unit that measures the voltage of the lithium-sulfur battery; a current application unit that applies a current to maintain the voltage of the lithium-sulfur battery within a certain range; and a control unit that controls the current application unit based on the voltage measurement result of the voltage measurement unit to maintain the voltage of the lithium-sulfur battery within the certain range, thereby suppressing gas generation in a lithium-sulfur battery that has undergone an activation step.

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for suppressing gassing in lithium-sulfur batteries.

[0002] This application claims priority to Korean Patent Application No. 10-2022-0110383, filed on August 31, 2022, and Korean Patent Application No. 10-2022-0183789, filed on December 23, 2022. [Background technology]

[0003] As interest in energy storage technology grows, its application fields expand to include mobile phones, tablets, laptops, and camcorders, as well as electric vehicles (EVs), hybrid electric vehicles (HEVs), and energy storage devices and systems. Research and development into electrochemical devices is also increasing. Electrochemical devices are the most popular area in this regard, with the development of rechargeable lithium-sulfur batteries and other secondary batteries attracting particular attention. In recent years, the development of these secondary batteries has led to research into new electrode and battery designs to improve capacity density and specific energy density.

[0004] Among these secondary batteries, lithium-sulfur (LiS) batteries have been gaining attention as a next-generation secondary battery capable of replacing lithium-ion batteries due to their high energy density in the fields of EVs, HEVs, and energy storage devices and systems. Lithium-sulfur is used as the positive electrode active material, and when a lithium-sulfur battery discharges, a reduction reaction of sulfur and an oxidation reaction of lithium metal occur, during which sulfur transforms from a ring-structured S8 to a linear-structured lithium polysulfide (Li2S2, Li2S4, Li2S6, Li2S8). Such lithium-sulfur batteries are characterized by a gradual discharge voltage until polysulfide (PS) is completely reduced to LiS.

[0005] However, lithium polysulfide, an intermediate product of lithium-sulfur batteries, is easily dissolved in electrolytes and continues to dissolve during discharge, reducing the amount of positive electrode active material and generating gas through reaction with the electrolyte. This accelerates battery degradation and causes the battery volume to expand due to gas generation, making it difficult to ensure stability. Lithium-sulfur batteries are frequently exposed to high temperatures, which exacerbates the above-mentioned problems. Lithium-sulfur batteries are particularly susceptible to high temperatures, and when exposed to high temperatures, gas generation accelerates due to the reaction with the electrolyte.

[0006] Therefore, attempts have been made to suppress gas generation by generating gas in advance during the manufacturing process of lithium-sulfur batteries and then removing it, but this method cannot prevent gas generation that occurs after the manufactured lithium-sulfur batteries are installed in EVs, HEVs, energy storage devices, and systems.

[0007] Various research and development efforts have been conducted to suppress or prevent gas generation, such as coating the positive electrode of a lithium-sulfur battery or adding additives to the separator or electrolyte. However, further research and development is still needed. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an apparatus and method for suppressing gassing in lithium-sulfur batteries, particularly those that overcome the shortcomings of the prior art. [Means for solving the problem]

[0009] The present inventors have found that the above problems can be solved by the gas suppression device and gas suppression method described below.

[0010] The first embodiment is 1. An apparatus for suppressing gassing in a lithium-sulfur battery that has undergone an activation stage, comprising: a voltage measurement unit configured to measure a voltage of the lithium-sulfur battery; a current applying unit configured to apply a current to the lithium-sulfur battery; and a control unit configured to control the current application unit based on the result of the voltage measurement by the voltage measurement unit to maintain the voltage of the lithium-sulfur battery within a certain range.

[0011] According to the second embodiment, in the first embodiment, The control unit compares the voltage measured by the voltage measurement unit with a preset reference voltage, and if the voltage measured by the voltage measurement unit is less than the reference voltage, controls the current application unit to apply a current to the lithium-sulfur battery.

[0012] According to the third embodiment, in the first or second embodiment, The battery further includes a storage unit for storing the lithium-sulfur battery, and a temperature measuring unit for measuring a temperature in the storage unit, The control unit adjusts the voltage measurement period of the voltage measurement unit in accordance with the temperature measured by the temperature measurement unit.

[0013] According to the fourth embodiment, in any one of the first to third embodiments, The gas suppression device for a lithium-sulfur battery further includes a storage unit for storing the lithium-sulfur battery, and a temperature control unit for controlling the temperature inside the storage unit.

[0014] According to the fifth embodiment, in any one of the first to fourth embodiments, The current application unit relates to a gas suppression device for a lithium-sulfur battery, which applies a current of 0.01 C or less to the lithium-sulfur battery.

[0015] According to the sixth embodiment, in any one of the first to fifth embodiments, The lithium-sulfur battery is a gas suppression device for a lithium-sulfur battery that has undergone an activation step less than 24 hours ago. The lithium-sulfur battery is within 24 hours of the end of the activation step, i.e., immediately after the activation step is completed.

[0016] According to the seventh embodiment, in any one of the first to sixth embodiments, The lithium-sulfur battery is charged to a SOC (State of Charge) of 90% or more, and the gas suppression device for the lithium-sulfur battery relates to the lithium-sulfur battery.

[0017] The eighth embodiment is: 1. A method for inhibiting gassing in a lithium-sulfur battery that has undergone an activation step, comprising: a voltage measurement step of measuring a voltage of the lithium-sulfur battery every time a predetermined time has elapsed; a control step of controlling the application of a current so that the voltage of the lithium-sulfur battery is maintained within a certain range based on the result of the voltage measurement; and applying a current to the lithium-sulfur battery so that the voltage of the lithium-sulfur battery is maintained within a certain range according to control. The gas suppression method for the lithium-sulfur battery may be performed using the gas suppression device according to any one of the first to seventh embodiments. The activation step, i.e., the activation step performed on the lithium-sulfur battery, may be a step prior to the voltage measurement step.

[0018] According to the ninth embodiment, in the eighth embodiment, The control step compares the voltage measured in the voltage measurement step with a reference voltage (particularly, a preset reference voltage), and controls to apply a current to the lithium-sulfur battery if the measured voltage is lower than the reference voltage.

[0019] According to the tenth embodiment, in the eighth or ninth embodiment, the lithium-sulfur battery is housed in a housing; Further comprising measuring the temperature of the storage section; In the voltage measuring step, a voltage measurement period is adjusted according to the measured temperature of the storage portion.

[0020] According to the eleventh embodiment, in the tenth embodiment, The method further includes adjusting the temperature in the storage compartment in response to the measured temperature.

[0021] According to the twelfth embodiment, in any one of the eighth to eleventh embodiments, In the current application step, a current of 0.01 C or less is applied. For example, a current of 0.01 A per second is applied to the lithium-sulfur battery.

[0022] According to the thirteenth embodiment, in any one of the eighth to twelfth embodiments, The lithium-sulfur battery is housed in a battery case, In the current application step, the current is applied so that the volume change of the battery case is 1% or less.

[0023] According to the 14th embodiment, in any one of the 8th to 13th embodiments, The activation step relates to a method for suppressing gas in a lithium-sulfur battery, the method including charging and discharging the lithium-sulfur battery one or more times.

[0024] According to the 15th embodiment, in any one of the 8th to 14th embodiments, In the activation step, the lithium-sulfur battery is charged and discharged at a current of 0.02 C to 5 C.

[0025] According to the 16th embodiment, in any one of the 8th to 15th embodiments, The lithium-sulfur battery is one from which gas generated during the activation step has been removed, and the present invention relates to a method for suppressing gas generation in a lithium-sulfur battery.

[0026] The above embodiment may also be applied to an electric vehicle including a battery management system and a battery pack. [Effects of the Invention]

[0027] According to an embodiment of the present invention, gas generation in a lithium-sulfur battery can be effectively suppressed. In particular, in the case of the present invention, gas generation when a lithium-sulfur battery is stored or installed in a high-temperature environment can be suppressed in a relatively simple manner.

[0028] Furthermore, according to an embodiment of the present invention, the generation of lithium polysulfide during discharge of a lithium-sulfur battery can be suppressed, thereby suppressing the generation of gas generated when lithium polysulfide dissolves in the electrolyte and preventing cell degradation due to the chemical reaction of lithium polysulfide with organic solvents or lithium salts.

[0029] The present invention has many other advantages, which will be described in each embodiment, but explanations of advantages that can be easily inferred by those skilled in the art will be omitted.

[0030] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention, serve to further understand the technical concept of the present invention, and the present invention should not be interpreted as being limited only to the matters described in the drawings. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a perspective view of a lithium-sulfur battery according to one embodiment of the present invention; [Figure 2] 1 is a block diagram showing a schematic configuration of a gas suppression device according to an embodiment of the present invention; [Figure 3]1 is a block diagram showing one embodiment of a gas suppression device according to the present invention; [Figure 4] 1 is a perspective view showing an embodiment to which a gas suppression device according to the present invention is applied. [Figure 5] 1 is a diagram showing an embodiment to which a gas suppression device according to the present invention is applied. [Figure 6] 1 is a block diagram showing an embodiment to which a gas suppression device according to the present invention is applied. [Figure 7] 1 is a flow diagram of a gas suppression method for a lithium-sulfur battery according to one embodiment of the present invention. [Figure 8] 1 is a voltage and current graph of the lithium-sulfur batteries according to Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0032] The present invention will be described in detail below with reference to the drawings. The terms and phrases used in the specification and claims are not to be construed as being limited to their ordinary and dictionary meanings, but are to be construed as having meanings and concepts that correspond to the technical ideas of the present invention, in accordance with the principle that the inventors themselves can appropriately define the concepts of terms in order to best explain the invention.

[0033] Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are merely the most desirable embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and that there may be various equivalents and modifications that can be substituted therefor at the time of this application.

[0034] In this specification, when a part is described as "comprising" a certain component, this does not exclude other components, and means that other components may be further included, unless otherwise specified. However, terms such as "comprise," "comprise," and "contain" may have the meaning of "comprise," unless expressly excluded.

[0035] In this specification, the expression "A and / or B" means "A, B, or all of these."

[0036] As used herein, the term "polysulfide" refers to "polysulfide ions (S x 2- , x=8, 6, 4, 2) and Lithium polysulfide (Li2S x or LiS x , x=8, 6, 4, 2).

[0037] In this specification, the same reference numbers may be used for similar devices.

[0038] The term "unit" as used herein may refer to at least one of an electric circuit, an electric circuit that executes instructions, a logical electric circuit, and a device. For example, a "current applying unit" as used herein may refer to a device that applies a current, or may refer to an electric circuit that includes applying a current. As another example, a "voltage measuring unit" as used herein may refer to a device that measures a voltage, or may refer to an electric circuit that includes measuring a voltage.

[0039] A gas suppression device according to one embodiment of the present invention is a device for suppressing gas generation in a lithium-sulfur battery that has undergone an activation step. In particular, the gas suppression device according to the present invention is suitable for suppressing gas generation in a lithium-sulfur battery, which may be provided after the lithium-sulfur battery has undergone the activation step described herein.

[0040] The activation step may include a formation process and a degassing process. Here, the formation process is a process of charging and discharging the battery to check the battery capacity and activate it. For example, the lithium-sulfur battery may be activated by charging and discharging the lithium-sulfur battery with a current of 0.02 C to 5 C. The degassing process refers to a process of removing gas generated during the formation process. In the activation step, a current is applied to the lithium-sulfur battery to generate gas, which can then be removed. However, apart from applying a current to the lithium-sulfur battery in the activation step, the device according to the present invention may also suppress gas generation itself by applying a current to the lithium-sulfur battery that has undergone the activation step. The lithium-sulfur battery may be assembled, stored, or installed in, for example, electronic and electrical devices, EVs and HEVs, and energy storage devices and systems.

[0041] FIG. 1 is a perspective view of a lithium-sulfur battery according to one embodiment of the present invention.

[0042] The shape of the battery case 20 of the lithium-sulfur battery 10 may be a coin shape, a cylindrical shape, a square shape, a pouch shape, etc. The electrode assembly 30 disposed inside the battery case 20 is a chargeable and dischargeable power generating element having a structure in which a positive electrode, a negative electrode, and a separator are stacked.

[0043] The electrode assembly 30 may be a jelly-roll type electrode assembly in which a separator is interposed between a positive electrode and a negative electrode, and the positive electrode, separator, and negative electrode may be in sheet form and provided in a rolled-up state. The electrode assembly may be a stack type in which a plurality of positive electrodes and negative electrodes are stacked in order with a separator sandwiched therebetween, or a stack / folding type electrode assembly in which a long separator is wound around a stack type unit cell.

[0044] The battery case may contain an electrolyte that serves as a conductive path for the electrode assembly during charging and discharging. The electrolyte may be liquid or solid, for example, a liquid organic electrolyte such as an ether-based electrolyte, but is not limited thereto. Other liquid or solid electrolytes may also be used.

[0045] The positive electrode and negative electrode may be connected to a positive electrode lead 40 and a negative electrode lead 50, respectively. FIG. 1 shows a lithium-sulfur battery in which the positive electrode lead 40 and the negative electrode lead 50 are disposed together on the top surface of a battery case 20. FIG. 1 also shows a vent 60 provided between the positive electrode lead and the negative electrode lead on the top surface of the battery case 20 for safety reasons. For example, if the internal pressure of the lithium-sulfur battery increases abnormally and the vent 60 is activated, the vent 60 may discharge the lithium-sulfur battery.

[0046] The charging and discharging of the lithium-sulfur battery includes lithium desorption from the negative electrode during discharging and lithium insertion into the negative electrode during charging, and can be expressed as follows:

[0047] Discharge: Sulfur reacts with lithium ions (Li + ) and electrons (e - ) and is returned to you. S8+16Li + +16 e- →8L2S Lithium metal is converted into lithium ion (Li + ) and electrons (e - ) and is oxidized. Li → Li + +e -

[0048] charging: Sulfur reacts with lithium ions (Li + ) and electrons (e - ) and is oxidized, 8L2S → S8 + 16Li + +16e Lithium metal is converted into lithium ion (Li+ ) and electrons (e - ) and will be refunded. Li + +e - →Li

[0049] FIG. 2 is a block diagram showing a schematic configuration of a gas suppression device 100 according to one embodiment of the present invention.

[0050] Referring to FIG. 2, a gas suppression device 100 according to an embodiment of the present invention may include a voltage measurement unit 110, a current application unit 120, and a control unit .

[0051] The voltage measurement unit 110 may be configured to measure the voltage of the lithium-sulfur battery. The voltage measurement unit 110 may measure the voltage using a voltage sensor. Specifically, the voltage measurement unit 110 may further include a positive electrode contact terminal and a negative electrode contact terminal. Here, the positive electrode contact terminal and the negative electrode contact terminal may be configured to contact a positive electrode lead and a negative electrode lead electrically connected to the electrode assembly of the lithium-sulfur battery 10, respectively. In this embodiment, the voltage measurement unit 110 may measure the voltage of the lithium-sulfur battery 10 while the positive electrode contact terminal and the negative electrode contact terminal are in contact with the positive electrode lead and the negative electrode lead of the lithium-sulfur battery 10, respectively. The voltage measurement unit 110 may then transmit the voltage measurement result to the control unit 130.

[0052] The current applying unit 120 may be configured to apply a current to the lithium-sulfur battery 10. Specifically, the current applying unit 120 may apply a current to the lithium-sulfur battery 10 using a positive electrode contact terminal and a negative electrode contact terminal included in the voltage measuring unit 110. Alternatively, the current applying unit 120 may include separate positive electrode contact terminals and separate negative electrode contact terminals that contact the positive electrode lead and the negative electrode lead of the lithium-sulfur battery 10, respectively, and the current applying unit 120 may apply a current to the lithium-sulfur battery 10 using these contact terminals.

[0053] The control unit 130 may be configured to receive a result of the voltage measurement by the voltage measurement unit 110. The control unit 130 may also be configured to control the current application unit 120. For example, the control unit 130 may control the magnitude, supply amount, and current application time of the current application unit 120. To this end, the control unit 130 may provide a control signal to the current application unit 120. For example, the control unit may be a microprocessor or a logic circuit. The control unit may execute commands stored in a memory, such as a semiconductor memory or an external storage medium, to perform a required function.

[0054] The control unit 130 can maintain the voltage of the lithium-sulfur battery 10 within a certain range by controlling the current applying unit 120. In particular, the control unit 130 can control the current application of the current applying unit 120 using the measurement result of the voltage measuring unit 110.

[0055] Such an embodiment of the gas suppression device 100 of the present invention can suppress gas generation in the lithium-sulfur battery 10. In particular, suppressing gas generation in the lithium-sulfur battery 10 can prevent expansion of the lithium-sulfur battery 10, thereby reducing damage to the lithium-sulfur battery and reducing the risk of explosion.

[0056] Furthermore, this embodiment of the gas suppression device 100 according to the present invention can prevent the lithium-sulfur battery 10 from discharging beyond a certain level. In particular, lithium polysulfide, an intermediate product generated by the reaction of the positive electrode active material during the discharge process of the lithium-sulfur battery 10, has a tendency to dissolve in the electrolyte. However, since the gas suppression device 100 according to the present invention prevents the discharge of the lithium-sulfur battery 10, it is possible to prevent the lithium polysulfide from dissolving in the electrolyte and reacting. Furthermore, since the lithium polysulfide is prevented from dissolving in the electrolyte, it is possible to prevent a decrease in the amount of the positive electrode active material and deterioration of the electrolyte.

[0057] In particular, according to an embodiment of the gas suppression device 100 of the present invention, gas generation can be effectively suppressed when the lithium-sulfur battery 10 is stored in a high-temperature environment at room temperature (e.g., 23°C) or higher. For example, when the lithium-sulfur battery 10 is stored at a temperature above 30°C or 40°C, gas generation is likely to occur. In this case, by applying the gas suppression device 100 of the present invention to the lithium-sulfur battery 10, gas generation in the lithium-sulfur battery 10 can be suppressed relatively easily.

[0058] In an embodiment of the present invention, the control unit 130 may be configured to compare the voltage measured by the voltage measurement unit 110 with a preset reference voltage. Here, the reference voltage may be preset based on the fully charged voltage of the lithium-sulfur battery 10. For example, the reference voltage may be set to a voltage that is 90%, 95%, 98%, or 100% of the fully charged voltage of the lithium-sulfur battery 10. However, the reference voltage may be set in various ways depending on various conditions, such as the type, manufacturing method, and storage method of the lithium-sulfur battery 10, and the device, vehicle, or system in which the lithium-sulfur battery is installed. The reference voltage may be stored in a memory (e.g., a semiconductor memory) built into the control unit 130 or in various other recording media external to the control unit 130.

[0059] The control unit 130 may also be configured to determine whether the voltage measured by the voltage measurement unit 110 is less than a reference voltage. For example, if the reference voltage is set to 2.4 V, the control unit 130 may determine whether the voltage measured by the voltage measurement unit 110 is less than 2.4 V. If the measured voltage is less than the reference voltage, the control unit 130 may control the current application unit 120 to apply a current to the lithium-sulfur battery 10. For example, as in the above embodiment, if the reference voltage is set to 2.4 V and the measured voltage of the lithium-sulfur battery 10 is less than 2.4 V, e.g., 2.39 V, the control unit 130 may control the current application unit 120 to apply a current to the lithium-sulfur battery 10.

[0060] This embodiment of the present invention further improves the gas suppression effect of the lithium-sulfur battery 10. In particular, lithium polysulfide may be generated when the lithium-sulfur battery 10 is discharged. However, by setting the reference voltage close to the fully charged voltage of the lithium-sulfur battery 10 as in the above embodiment, current is applied as soon as the lithium-sulfur battery 10 is discharged. Therefore, in this case, the generation of lithium polysulfide is effectively suppressed, and thus gas generation in the lithium-sulfur battery 10 can be more effectively suppressed.

[0061] In an embodiment of the present invention, the voltage measurement unit 110 of the gas suppression device 100 according to the present invention may be configured to measure the voltage of the lithium-sulfur battery 10 periodically or aperiodically.

[0062] As a specific example, the voltage measurement unit 110 may be configured to periodically measure the voltage of the lithium-sulfur battery 10 every 0.01 seconds to 1 hour, every 0.1 seconds to 10 minutes, or every 5 seconds. Alternatively, the voltage measurement unit 110 may measure the voltage at specific intervals within a range of 0.01 seconds to 100 seconds. However, such voltage measurement intervals may vary depending on various conditions, such as the type of lithium-sulfur battery 10 and the ambient temperature.

[0063] In an embodiment of the present invention, the gas suppression device 100 according to the present invention may further include a storage unit 140 for storing one or more lithium-sulfur batteries. The storage unit 140 may be separate from the gas suppression device 100. The storage unit 140 may have various shapes, patterns, sizes, or materials. For example, the storage unit 140 may be a storage space for a lithium-sulfur battery of an electronic device, a storage space for a lithium-sulfur battery pack of an EV or HEV, a storage chamber for a lithium-sulfur battery, a storage space for one or more lithium-sulfur batteries in an energy storage device or system, etc.

[0064] For example, the storage unit 140 may have an empty space therein and be configured to store, preserve, or install one or more lithium-sulfur batteries 10. The storage unit 140 may also be configured to store the voltage measuring unit 110, the current applying unit 120, and the control unit 130 of the gas suppression device 100 according to the present invention together with the lithium-sulfur battery 10. The storage unit 140 may also refer to a space capable of storing one or more lithium-sulfur batteries 10.

[0065] In an embodiment of the present invention, the lithium-sulfur battery 10 is housed in the housing 140, thereby preventing the lithium-sulfur battery 10 from being affected by the external environment of the housing 140. For example, the housing 140 may be an enclosure that protects and safely stores the lithium-sulfur battery 10 by preventing penetration of foreign matter from the outside. The housing 140 may also include means (e.g., a shock absorbing device) for protecting the lithium-sulfur battery 10, voltage measuring unit 110, current applying unit 120, and control unit 130 of the gas suppression device 100 according to the present invention from external mechanical influences (such as impacts and drops).

[0066] In an embodiment of the present invention, the gas suppression device 100 according to the present invention may further include a temperature measurement unit 150 .

[0067] The temperature measuring unit 150 may be configured to measure the temperature of the lithium-sulfur battery 10. The temperature measuring unit 150 may measure the temperature using a temperature sensor. For example, the temperature measuring unit 150 may measure temperatures at various locations, such as the ambient temperature of the gas suppression device according to the present invention, the surface temperature of the lithium-sulfur battery 10, the ambient temperature of the lithium-sulfur battery 10, and / or the temperature of the housing 140 if the lithium-sulfur battery 10 is housed in the housing 140.

[0068] Furthermore, the temperature measuring unit 150 may be configured to transmit measured temperature information to the control unit 130. The measured temperature information may be, for example, the ambient temperature of the gas suppression device according to the present invention, the surface temperature of the lithium-sulfur battery 10, the ambient temperature of the lithium-sulfur battery 10, and / or the temperature of the storage unit 140. In this case, the control unit 130 may be configured to adjust the voltage measurement period (particularly, the time interval at which the voltage is measured) of the voltage measuring unit 110 according to the temperature information measured by the temperature measuring unit 150.

[0069] In this embodiment, the reference temperature may be set in advance and stored in advance in the memory of the control unit 130 or in another component (such as an external recording medium that is connected or can be connected to the control unit). The control unit 130 may then compare the temperature measured by the temperature measuring unit 150 with the preset (and / or pre-stored) reference temperature. At this time, if the temperature measured by the temperature measuring unit 150 is higher than the reference temperature, the control unit 130 may shorten the voltage measurement period of the voltage measuring unit 110.

[0070] For example, if the voltage measurement period of the voltage measurement unit 110 is 100 seconds when the measured temperature is lower than the reference temperature, and the measured temperature becomes higher than the reference temperature, the control unit 130 may control the voltage measurement period to be 10 seconds. The lithium-sulfur battery 10 has a faster discharge rate at higher temperatures. According to the above embodiment, by shortening the voltage measurement period in the temperature range where the discharge rate is fast, current can be applied immediately (or in advance) when the lithium-sulfur battery 10 is discharged, thereby improving the gas suppression effect.

[0071] Meanwhile, if the temperature measured by the temperature measuring unit 150 is lower than the reference temperature, the control unit 130 may increase the voltage measurement interval of the voltage measuring unit 110. Since the lithium-sulfur battery 10 discharges slowly at low temperatures, increasing the interval at which the voltage measuring unit 110 measures the voltage can reduce energy consumption due to frequent voltage measurements.

[0072] In an embodiment of the present invention, the current applying unit 120 may be configured to apply a current to the lithium-sulfur battery 10 at a C-rate of 0.01 C or less. In an embodiment of the present invention, the current applying unit 120 may be configured to apply a current to the lithium-sulfur battery 10 at a C-rate of 0.0005 C or more, 0.001 C or more, or 0.005 C or more. In an embodiment of the present invention, the current applying unit 120 may be configured to apply a current to the lithium-sulfur battery 10 at a C-rate of 0.01 C or less or 0.0005 C or more. The C-rate control operation of the current applying unit 120 may be performed by the control unit 130.

[0073] For example, when the lithium-sulfur battery 10 used in the device according to the present invention is discharged to a certain level or more, the current applying unit 120 may apply current at a C-rate of 0.02 C to 5 C. The current applying unit 120 may also apply current at a C-rate of 0.02 C or more, 0.05 C or more, 0.1 C or more, or 0.5 C or more. The current applying unit 120 may also apply current at a C-rate set to 2 C or less or 1 C or less. Furthermore, the current applying unit 120 may apply current at various C-rates, such as 0.02 C to 2 C, 0.05 C to 2 C, 0.05 C to 1 C, 0.1 C to 1 C, or 0.5 C to 1 C.

[0074] In particular, the current applying unit 120 may be configured to change the applied current C rate according to the SOC (State of Charge) of the lithium-sulfur battery 10. Furthermore, the current applying unit 120 may be configured to gradually decrease the applied current C rate as the SOC of the lithium-sulfur battery 10 increases.

[0075] For example, when the SOC of the lithium-sulfur battery 10 is 97% or less (e.g., 90% to 97%), the current applying unit 120 may apply a current to the lithium-sulfur battery 10 at a C-rate of 0.02 C to 0.05 C or 0.02 C. When the SOC of the lithium-sulfur battery 10 exceeds 97% (e.g., 98% to 99.5% or 98% to 99.9%), the current applying unit 120 may apply a current to the lithium-sulfur battery 10 at a lower C-rate of 0.005 C to 0.01 C or 0.01 C. That is, in the above embodiment, the current applying unit 120 may charge the lithium-sulfur battery 10 at a relatively high C-rate up to a certain level, and then apply a current at a lower C-rate after the lithium-sulfur battery 10 has been charged to or above the certain level.

[0076] According to this embodiment of the present invention, lithium-sulfur battery 10 can be charged quickly when its SOC is low, and can be safely charged when its SOC is high. However, the current applied to lithium-sulfur battery 10 is not limited to the above-mentioned range, and a current can be applied at a C rate that allows lithium-sulfur battery 10 to be properly charged without overcharging or damaging the battery itself.

[0077] The gas suppression device 100 for a lithium-sulfur battery 10 according to the present invention may further include a temperature control unit 160. The temperature control unit 160 may be configured to control the temperature of the interior space of the storage unit 140. For example, the temperature control unit 160 may control the temperature of the storage unit 140 to maintain the temperature between 0°C and 40°C, 10°C and 40°C, 20°C and 40°C, or room temperature (23°C) and 40°C, depending on the desired results. However, the temperature of the storage unit 140 controlled by the temperature control unit 160 is not limited to the above temperature range, and may be configured to maintain various other temperatures suitable for storing the lithium-sulfur battery 10, depending on the desired results.

[0078] According to this embodiment of the present invention, the lithium-sulfur battery 10 can be stored at an appropriate temperature, and the storage temperature may be within the above-mentioned range. In particular, the lithium-sulfur battery 10 may be rapidly discharged under high temperature conditions, but the temperature control unit 160 can prevent the lithium-sulfur battery 10 from rapidly discharging by controlling the internal temperature of the storage unit 140 in which the lithium-sulfur battery 10 is stored.

[0079] Furthermore, when the gas suppression device 100 according to the present invention includes a temperature measuring unit 150 as in the above-described embodiment, the temperature measuring unit 150 may measure the temperature inside the storage unit 140 and transmit the measurement information to the control unit 130. The control unit 130 may then determine whether the temperature inside the storage unit 140 exceeds or falls below a preset reference range, and if determined to be above or below the reference range, may control the temperature adjusting unit 160 to adjust the temperature inside the storage unit 140 so that it falls within the reference range. The temperature adjusting unit 160 may be controlled by the control unit 130 and may be, or may be equipped with, a cooling unit, a heating unit, or a combined cooling and heating unit, as long as it has a temperature adjusting function.

[0080] In an embodiment of the present invention, the lithium-sulfur battery 10 accommodated in the accommodation unit 140 may be one that has not yet been in an activation stage for more than 24 hours. That is, the accommodation unit 140 may accommodate the lithium-sulfur battery 10 in its internal space less than 24 hours after the activation stage of the lithium-sulfur battery 10. That is, the lithium-sulfur battery that is applied to the gas suppression device according to the present invention may be one that has been in a state within 24 hours since the end of the activation stage, in other words, one that has just completed the activation stage.

[0081] Furthermore, the lithium-sulfur battery 10 may be stored in the internal space within 10 hours, preferably within 5 hours, and particularly within 1 hour after the activation step. If the lithium-sulfur battery 10 is left unused, it may spontaneously discharge, and lithium polysulfide may be generated during discharge. To prevent this, the lithium-sulfur battery 10 is preferably applied to the gas suppression device 100 of the present invention within the above-mentioned time range after the activation step. However, the time range is not necessarily limited to the above-mentioned time range, and may vary depending on the storage and storage conditions of the lithium-sulfur battery 10, such as temperature. For example, a lithium-sulfur battery 10 left at a high temperature may spontaneously discharge more rapidly, so it is preferable to apply the gas suppression device 100 of the present invention to the lithium-sulfur battery 10 sooner than the above-mentioned time range after the activation step. The gas suppression device 100 of the present invention may be applied to the lithium-sulfur battery 10 after the activation step.

[0082] The lithium-sulfur battery 10 is charged and / or discharged one or more times from the activation stage, and gas may be generated during the charging and / or discharging. The gas generated during the charging and / or discharging process is then removed. The charged lithium-sulfur battery 10 is then stored in the storage compartment 140. However, if a long period of time has passed since charging (e.g., more than 24 hours), lithium polysulfide may be generated as the lithium-sulfur battery 10 self-discharges, which may result in gas generation in the lithium-sulfur battery 10.

[0083] Therefore, it is preferable that the lithium-sulfur battery 10 charged in the activation step be stored in the device and storage unit 140 according to the present invention as quickly as possible. Preferably, the lithium-sulfur battery 10 is stored in the storage unit 140 immediately after the activation step. However, the present invention is not limited to this time range, and the time can be appropriately selected depending on the manufacturing process of the lithium-sulfur battery 10.

[0084] In an embodiment of the present invention, the lithium-sulfur battery 10 after the activation step may be charged to a SOC (State of Charge) of 90% or more. The gas suppression device according to the present invention is configured to apply a current of 0.01 C or less to the lithium-sulfur battery 10 to prevent damage to the lithium-sulfur battery 10. Therefore, if the SOC of the lithium-sulfur battery 10 after the activation step is low, it may take a long time to fully charge the lithium-sulfur battery 10. Therefore, the lithium-sulfur battery 10 applicable to the gas suppression device according to the present invention may have an SOC within the above range. However, the SOC of the lithium-sulfur battery 10 after the activation step is not limited to the above numerical range, and even a lithium-sulfur battery 10 with a low SOC may be applied to and charged by the gas suppression device according to the present invention.

[0085] FIG. 3 is a block diagram showing one embodiment of a gas suppression device according to the present invention.

[0086] The housing 140 may house the lithium-sulfur battery 10, a temperature control unit 160, and a temperature measurement unit 150. In one embodiment of the present invention, the housing 140 may not include the temperature control unit 160 and the temperature measurement unit 150, but may instead include a temperature sensor and an air conditioner and / or a heater. The lithium-sulfur battery 10 may be connected to the voltage measurement unit 110 and the current application unit 120. The voltage measurement unit 110 may measure the voltage of the lithium-sulfur battery 10, and the current application unit 120 may apply a current to the lithium-sulfur battery 10. In this case, the control unit 130 connected to the voltage measurement unit 110 and the current application unit 120 may compare the measured voltage with a reference voltage and control the current application unit 120 to apply a current to the lithium-sulfur battery 10. The control unit 130 may also be connected to the temperature measurement unit 150 and the temperature control unit 160. The control unit 130 receives the internal temperature of the storage unit 140 measured by the temperature measurement unit 150, and if the received temperature is outside the reference temperature range, the control unit 130 may control the temperature adjustment unit 160 to adjust the internal temperature of the storage unit 140.

[0087] 4 is a perspective view showing an embodiment of a storage chamber to which a gas suppression device according to the present invention is applied. Although FIG. 4 illustrates a storage chamber, the gas suppression device according to the present invention can also be applied to an energy storage device and an energy storage system.

[0088] The lithium-sulfur battery 10 is accommodated in the accommodation unit 140, and a temperature measuring unit 150 and a temperature adjusting unit 160 may be attached to the inner wall of the accommodation unit 140. In this case, the temperature measuring unit 150 and the temperature adjusting unit 160 may be spatially separated.

[0089] The temperature measuring unit 150 and the temperature adjusting unit 160 may be located in the gas suppression device, and the temperature sensor unit 170 and the heating / cooling unit 180 may be located on the inner wall of the storage unit 140. Specifically, the heating / cooling unit may be a compression / expansion refrigeration cycle system, and the cooler may be a fan. In one embodiment, the heating / cooling unit may be a heat pump or a thermoelectric module using the Peltier effect.

[0090] The voltage measuring unit 110 is connected to the positive and negative electrode leads of the lithium-sulfur battery 10 through a positive and negative electrode contact terminal and may measure the voltage of the lithium-sulfur battery 10. The control unit 130 receives the measured voltage and controls the current applying unit 120 based on the measurement result to apply a current to the lithium-sulfur battery 10 so that the voltage of the lithium-sulfur battery 10 is maintained within a certain range. Here, the current applying unit 120 may apply a current to the lithium-sulfur battery 10 through the positive and negative electrode contact terminals. The control unit 130 may receive the temperature measured from the temperature measuring unit 150 and control the temperature adjusting unit 160 to maintain the temperature inside the storage unit 140 within a preset range based on the measurement result.

[0091] In addition, the temperature measuring unit 150 may measure the internal temperature of the storage unit 140 through the temperature sensor unit 170 and transmit the measured temperature to the control unit 130, which may receive the measured temperature. The control unit 130 may control the temperature adjusting unit 160 based on the measured temperature to adjust the temperature of the storage unit 140 so that the internal temperature of the storage unit 140 is maintained within a certain range. The temperature adjusting unit 160 may adjust the temperature of the storage unit 140 by controlling the heating / cooling unit 180.

[0092] FIG. 5 is a diagram showing one embodiment of a gas suppression device according to the present invention, illustrating a battery management system (BMS) 200 and a storage unit 140 including a battery pack including a plurality of lithium-sulfur batteries 10 in an electric vehicle (e.g., an EV or HEV).

[0093] The BMS 200 may manage parameters for the batteries in the battery pack. The battery parameters managed by the BMS 200 may include the voltage of the battery pack, the voltage of each battery, the temperature of the battery pack, the battery State of Charge (SOC), the charge level of the battery pack, the battery State of Health (SOH), the battery voltage uniformity, and the battery pack State of Power (SOP), and may further include other battery-related factors. The BMS 200 may include the gas suppression device 100 according to the present invention as part of the battery parameter management, and the gas suppression device 100 may use the voltage measurement unit and the temperature measurement unit included in the BMS 200. The gas suppression device 100 may also be configured to use a separate voltage measurement unit and a separate temperature sensor unit.

[0094] 5, a battery pack including a plurality of lithium-sulfur batteries 10 may be mounted in the storage unit 140. The voltage measurement unit 110 may include a positive electrode contact terminal and a negative electrode contact terminal, which may be connected to the positive electrode lead and the negative electrode lead of the lithium-sulfur battery 10, respectively.

[0095] The control unit 130 may receive the result of measuring the voltage of each lithium-sulfur battery 10 and control the current applying unit 120 based on the received voltage to apply a current to each lithium-sulfur battery 10 so that the voltage of the lithium-sulfur battery 10 is maintained within a predetermined range. The current applying unit 120 may apply a current to each lithium-sulfur battery 10 using a positive electrode contact terminal and a negative electrode contact terminal.

[0096] The temperature measuring unit 150 may measure the internal temperature of the container 140 through the temperature sensor unit 170 and transmit the measured temperature to the control unit 130. The control unit 130 may also control the temperature adjusting unit 160 based on the measured temperature to adjust the temperature of the container 140 so that the internal temperature of the container 140 is maintained within a preset range.

[0097] Air conditioning for the storage compartment 140 may be provided by an air conditioning system of the EV. Specifically, air conditioned by the air conditioning system of the EV may be supplied to the storage compartment 140 through a conduit 190 connected to the air conditioning system. The air conditioning system is a system for conditioning air and may be an air conditioner. For example, the air conditioning system may adjust the temperature, humidity, cleanliness, and flow of air.

[0098] 6 is a diagram illustrating an electronic device to which the gas suppression device 100 according to the present invention is applied. The electronic device may be, for example, a mobile phone, a tablet, a laptop, or a camcorder.

[0099] The storage unit 140 stores the lithium-sulfur batteries 10, and the voltage measurement unit 110 includes positive and negative contact terminals, which may be connected to the positive and negative leads of the lithium-sulfur batteries 10. The control unit 130 receives the voltage measurement results of the individual lithium-sulfur batteries 10 and controls the current application unit 120 based on the received voltage to apply current to each lithium-sulfur battery 10 so that the voltage of the lithium-sulfur battery 10 is maintained within a predetermined range. The current application unit 120 may apply current to each lithium-sulfur battery 10 using the positive and negative contact terminals connected to the positive and negative leads, respectively.

[0100] In one embodiment according to the present invention, the gas suppression device may not include a cooling system in connection with maintaining the temperature of the enclosure 140. In another embodiment, the gas suppression device may include a fan as a cooling system.

[0101] In the above embodiment, the temperature measuring unit 150 may measure the internal temperature of the storage unit 140 through the temperature sensor unit 170 and transmit the measured temperature to the control unit 130. The control unit 130 may control the temperature adjusting unit 160 to adjust the temperature of the storage unit 140 and maintain the internal temperature of the storage unit 140 within a predetermined range. The temperature adjusting unit 160 may control the heating / cooling unit 180 to maintain the internal temperature of the storage unit 140 within a predetermined range.

[0102] FIG. 7 is a flow diagram of a gas suppression method for a lithium-sulfur battery according to one embodiment of the present invention.

[0103] According to one embodiment of the present invention, there is provided a gas suppression method for a lithium-sulfur battery that has undergone an activation step (S100), the gas suppression method including a voltage measurement step (S200) of measuring the voltage of the lithium-sulfur battery 10, a control step (S300) of controlling the application of current to the lithium-sulfur battery 10, and a current application step (S400) of applying current to the lithium-sulfur battery 10.

[0104] The activation step (S100) may include a formation step (S110) and a degassing step (S120). Here, the formation step (S110) is a step of confirming the capacity of the battery by charging and discharging the battery at least once to activate it, and the degassing step (S120) is a step of removing gas generated in the formation step (S110). In the activation step (S100), a current may be applied to the lithium-sulfur battery 10 to generate gas, which may then be removed. However, apart from applying a current to the lithium-sulfur battery 10 in the activation step (S100), the gas suppression device according to the present invention may also suppress gas generation itself by applying a current to the lithium-sulfur battery 10 that has undergone the activation step (S100).

[0105] The following steps may be performed by a control unit that executes commands stored in a memory such as a semiconductor memory or an external recording medium.

[0106] The voltage measuring step (S200) of measuring the voltage of the lithium-sulfur battery 10 may be a step of measuring the voltage of the lithium-sulfur battery 10 every time a predetermined time elapses. The method of measuring the voltage of the lithium-sulfur battery 10 is not limited to a specific method. For example, the voltage of the lithium-sulfur battery 10 may be measured by connecting a positive electrode contact terminal and a negative electrode contact terminal to the positive electrode lead and the negative electrode lead of the lithium-sulfur battery 10, respectively.

[0107] The control step (S300) of controlling the application of current to the lithium-sulfur battery 10 is a step of controlling the application of current to the lithium-sulfur battery 10 so that the voltage of the lithium-sulfur battery 10 is maintained within a certain range based on the measured voltage.

[0108] The current applying step (S400) of applying a current to the lithium-sulfur battery 10 is a step of applying a current to the lithium-sulfur battery 10. The method of applying a current to the lithium-sulfur battery 10 is not limited to a specific method. For example, when the current applying unit 120 applies a current to the lithium-sulfur battery 10, the current may be applied to the lithium-sulfur battery 10 using a positive electrode contact terminal and a negative electrode contact terminal connected to the voltage measuring unit 110. Alternatively, the current applying unit 120 may have separate positive electrode contact terminals and a negative electrode contact terminals and apply a current to the lithium-sulfur battery 10 using the separate positive electrode contact terminals and negative electrode contact terminals.

[0109] According to this embodiment of the present invention, it is possible to suppress gas generation in the lithium-sulfur battery 10. In particular, when the lithium-sulfur battery 10 is exposed to a high-temperature environment exceeding room temperature, the gas suppression method according to the present invention can effectively suppress gas generation in the lithium-sulfur battery 10. Furthermore, suppressing gas generation can prevent the lithium-sulfur battery 10 from expanding, thereby reducing the risk of explosion.

[0110] In one embodiment of the present invention, the activation step (S100) may be a step of charging and discharging the battery one or more times by applying a current at a C rate of 0.02 C to 5 C. However, the charge and discharge are not limited to the above C rate range, and may be any C rate that is suitable for charging without damaging the lithium-sulfur battery 10.

[0111] According to one embodiment of the present invention, the control step (S300) of controlling the application of current to the lithium-sulfur battery 10 may be a step of comparing the voltage measured in the voltage measurement step (S200) with a preset reference voltage and controlling the application of current to the lithium-sulfur battery 10. Specifically, if the measured reference voltage is lower than the preset reference voltage, the current applying unit 120 may control the application of current to the lithium-sulfur battery 10.

[0112] In one embodiment of the present invention, the current applying step (S400) may be a step of applying a current so that the voltage of the lithium-sulfur battery 10 is maintained at or above a preset reference voltage. Specifically, the preset reference voltage may be 100%, 99%, 98%, or 95% of the fully charged voltage of the lithium-sulfur battery 10. When the lithium-sulfur battery 10 is discharged, lithium polysulfides are produced, which may result in gas generation, so it is most preferable to maintain the voltage of the lithium-sulfur battery 10 at the fully charged voltage.

[0113] In one embodiment of the present invention, the current applying step (S400) may be a step of applying a current at a C rate of 0.0005 C to 0.01 C. However, the intensity of the current applied in the current applying step is not limited to the above range, and the current may be applied within a range in which the lithium-sulfur battery 10 can be charged without being damaged.

[0114] In one embodiment of the present invention, the voltage measurement period of the voltage measurement step (S200) may be periodic or aperiodic. For example, the voltage of the lithium-sulfur battery 10 may be measured periodically every 5 seconds. Alternatively, the voltage may be measured at a specific period ranging from 0.01 seconds to 100 seconds. However, such a voltage measurement period may vary depending on various conditions, such as the type of lithium-sulfur battery 10 and the ambient temperature.

[0115] In one embodiment of the present invention, the lithium-sulfur battery 10 is housed in a housing 140, and the method may further include measuring the temperature of the housing 140. The method for measuring the temperature of the housing 140 is not limited to a specific method. For example, the housing 140 may include a temperature measuring unit 150 inside or on a wall surface of the housing 140, and the temperature measuring unit 150 may measure the temperature using a temperature sensor.

[0116] The voltage measurement period of the voltage measurement step may be adjusted depending on the measured temperature. For example, if the measured temperature is outside a predetermined reference temperature range, the voltage measurement period may be adjusted. Specifically, if the measured temperature is outside the reference temperature range, the voltage measurement period may be shortened.

[0117] This is because the discharge of the lithium-sulfur battery 10 is faster when the temperature is high, and so shortening the voltage measurement period allows the current applying unit 120 to apply current to the lithium-sulfur battery 10 immediately after discharge. On the other hand, the discharge of the lithium-sulfur battery 10 is slower when the temperature is low, and so lengthening the voltage measurement period can reduce energy consumption due to frequent voltage measurements.

[0118] Furthermore, the gas suppression method according to the present invention may further include a temperature adjusting step. The temperature adjustment may be to adjust the temperature to maintain a predetermined reference temperature range, i.e., adjust the internal temperature of the housing 140, and particularly adjust the ambient temperature of the lithium-sulfur battery 10. For example, if the predetermined reference temperature is 10°C to 20°C and the measured internal temperature of the housing 140 is 30°C, the internal temperature of the housing 140 may be adjusted to 20°C.

[0119] The method of adjusting the temperature may be performed by the cooling / heating unit and is not limited to a specific method. The cooling / heating unit may be a cooling unit, a heater, or a dual-purpose cooling / heating unit, or may be equipped with any of these and have a function of adjusting the temperature.

[0120] In one embodiment of the present invention, the lithium-sulfur battery 10 is housed in a battery case, and the current application step may be a step of applying a current so that the volume change of the battery case is 1% or less, 3% or less, 5% or less, or 10% or less. By applying the gas suppression method according to the present invention to the lithium-sulfur battery 10, the generation of lithium polysulfide can be suppressed, thereby suppressing gas generation, so that the volume change of the battery case can satisfy the above range.

[0121] In one embodiment of the present invention, the gas suppression method for a lithium-sulfur battery is applicable when the lithium-sulfur battery 10 is stored or installed at temperatures above 30°C, above 40°C, or above 50°C. Because high storage or storage temperatures cause lithium-sulfur batteries to discharge rapidly, applying the gas suppression method according to the present invention to lithium-sulfur batteries 10 stored or installed in these high temperature ranges can suppress the generation of lithium polysulfide and thereby suppress gas generation. However, the gas suppression method according to the present invention is not limited to the above temperature range, but can be applied to any temperature range in which a lithium-sulfur battery can be stored or installed, or any temperature range in which a lithium-sulfur battery can operate normally.

[0122] In one embodiment of the present invention, the gas suppression method for a lithium-sulfur battery can be applied when no load is applied to the lithium-sulfur battery 10. Specifically, when no load that consumes power is applied to the lithium-sulfur battery 10, the lithium-sulfur battery 10 is float-charged or equalized-charged, and the gas suppression method according to the present invention can be applied.

[0123] In one embodiment of the present invention, the gas suppression method for a lithium-sulfur battery can be applied to a battery management system of a battery pack including lithium-sulfur batteries 10. For example, the battery management system can float charge the lithium-sulfur batteries using charge stored in the battery pack. Alternatively, the battery management system can float charge the lithium-sulfur batteries from a separate battery or power supply device external to the battery pack.

[0124] In one embodiment of the present invention, a method for inhibiting gassing in a lithium-sulfur battery may include charging the lithium-sulfur battery until it is fully or partially charged and floating-charging the lithium-sulfur battery.

[0125] In one embodiment of the present invention, the floating charge step may be performed at a C rate of 0.01 C or less. Floating charge of a lithium-sulfur battery has the advantage of extending the life of the lithium-sulfur battery.

[0126] The float charging is a method of connecting a charger, a battery, and a load in parallel, charging the battery with electricity, power, or current supplied by the charger, and supplying power to the load. The charger may include the gas suppression device described above, and the battery may be a lithium-sulfur battery. In this float charging, if the load consumes a lot of power, power may be supplied to the load simultaneously from the charger and the battery being charged. Alternatively, the charger may bear all of the power consumed by the load, and only a weak charging current sufficient to replenish self-discharge may be supplied to the battery.

[0127] The float charge stage may maintain the voltage of the lithium-sulfur battery at or above 95% of the fully charged voltage.

[0128] In the float charging step, the float charging may be performed at a C rate of 0.0005C or more and 0.01C or less.

[0129] In the floating charge stage, the floating charge may be performed so as not to exceed the fully charged voltage of the lithium-sulfur battery.

[0130] In the float charging step, the lithium-sulfur battery may be float charged at a constant float voltage of 2.4V or less per cell.

[0131] In the float charging stage, the lithium-sulfur battery may be float-charged when no load is applied to the lithium-sulfur battery, for example, when the lithium-sulfur battery is connected to an electric vehicle and the electric vehicle is parked and not operating.

[0132] In the floating charge step, the lithium-sulfur battery may be float-charged for a predetermined time, for example, 1 hour to 10 hours, but is not limited to this time range.

[0133] The floating charge step may be performed at regular intervals when the temperature of the lithium-sulfur battery, the housing housing the lithium-sulfur battery, or the surroundings of the lithium-sulfur battery is 30° C. or higher. For example, when the surroundings of the lithium-sulfur battery are 30° C. or higher, floating charge may be performed at one-hour intervals to charge the lithium-sulfur battery.

[0134] The floating charging step may be performed when the temperature of the lithium-sulfur battery, the housing housing the lithium-sulfur battery, or the surroundings of the lithium-sulfur battery is 30°C or higher or 40°C or higher.

[0135] In one embodiment of the present invention, the floating charge step may be replaced by an equalization charge, automatic charge, or recovery charge step. When multiple batteries are used together for a long period of time, the charge state varies due to differences in the characteristics of each battery, resulting in potential differences. Equalization charge is a method of charging each battery at a uniform voltage by supplying a voltage approximately 10% higher than the voltage stored in the batteries. Automatic charge is a method of charging the batteries at an initial equalization charge depending on the amount of discharge, and then automatically switching to float charge once the batteries reach a fully charged state, thereby continuously floating charge. Recovery charge is a method of charging the batteries at a weak constant current for 40 to 50 hours, followed by discharging and recharging, and repeating this process several times to restore the plates to their original state.

[0136] In one embodiment of the present invention, a gas suppression method for a lithium-sulfur battery can be applied to a battery management system (BMS) of a battery pack. Here, charge stored in the battery pack can be used to perform float charging through the BMS. Alternatively, charge stored in an independent battery separate from the battery pack can be used to perform float charging through the BMS. Here, the BMS can be applied to an electric vehicle or other electric device.

[0137] In one embodiment of the present invention, the gas suppression method or apparatus for a lithium-sulfur battery may be applied while the lithium-sulfur battery 10 has an open circuit voltage corresponding to a partial or full charge. Specifically, a floating voltage may be provided while the lithium-sulfur battery 10 has an open circuit voltage corresponding to a partial or full charge.

[0138] The present invention will be described in more detail below with reference to examples and comparative examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the examples described below. The examples of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0139] Two identical lithium-sulfur batteries were fabricated in the following manner.

[0140] A sulfur-carbon composite, in which sulfur is supported on carbon nanotubes, was prepared as a positive electrode active material. The weight ratio of carbon nanotubes to sulfur was 1:3. Polyacrylic acid (PAA) was added as a binder and carbon fiber as a conductive material to prepare a positive electrode slurry. The weight ratio of the positive electrode active material, conductive material, and binder was 88:5:7.

[0141] Lithium metal was prepared as the negative electrode.

[0142] The electrolyte was prepared by dissolving 0.75M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and 1% by weight of lithium nitrate (LiNO3) in an organic solvent consisting of 1,3-dioxolane and dimethyl ether (DOL:DME = 1:1 (volume ratio)).

[0143] The prepared positive and negative electrodes were placed face to face, and a polyethylene separator with a thickness of 16 μm and a porosity of 46% was interposed between them. The resulting battery was then housed in a pouch-type battery case, and 70 μL of the prepared electrolyte was then injected to prepare a lithium-sulfur battery.

[0144] The two fabricated batteries were discharged to 1.8 V at 0.1 C, left for 20 minutes, and then charged again to 2.4 V at 0.1 C to undergo a formation process. They were then left at 25°C for two days to generate gas, and then a degassing process was performed to remove the gas. Each lithium-sulfur battery was then placed in a separate container and stored at 40°C for three days.

[0145] Example 1 One of the lithium-sulfur batteries stored in the storage unit was applied to the gas suppression device according to the present invention. The voltage measurement unit of the gas suppression device measured the voltage of the lithium-sulfur battery once per second, and when the SOC was less than 100%, the current application unit applied a current. The applied current was set to be less than 0.01 C.

[0146] Comparative Example 1 The other lithium-sulfur battery stored in the storage compartment was not fitted with the gas suppression device according to the present invention, and only the voltage was measured.

[0147] The voltage and current graphs of the lithium-sulfur batteries according to Example 1 and Comparative Example 1 are shown in FIG.

[0148] During the activation stage, both the lithium-sulfur batteries of Example 1 and Comparative Example 1 were charged to 2.4 V. Thereafter, the lithium-sulfur battery of Example 1 maintained 2.4 V because it was applied to the gas suppression device of the present invention. However, the lithium-sulfur battery of Comparative Example 1 gradually discharged and the voltage decreased.

[0149] The volume change of the battery case of the lithium-sulfur batteries according to Example 1 and Comparative Example 1 was observed.

[0150] The lithium-sulfur battery according to Example 1 did not change in volume up to 72 hours after storage, which confirmed that gas generation in the lithium-sulfur battery was suppressed.

[0151] On the other hand, when the lithium-sulfur battery according to Comparative Example 1 was observed after 24 hours of storage, expansion of the volume was confirmed, which confirmed that gas was generated in the lithium-sulfur battery.

[0152] As described above, the present invention has been described using limited embodiments and drawings, but the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by a person having ordinary knowledge in the technical field to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims.

Claims

1. A gas suppression device for a lithium-sulfur battery that suppresses gas in a lithium-sulfur battery that has undergone an activation step, a voltage measurement unit configured to measure a voltage of the lithium-sulfur battery; a current applying unit configured to apply a current to the lithium-sulfur battery; a control unit configured to control the current application unit based on the result of the voltage measurement by the voltage measurement unit to maintain the voltage of the lithium-sulfur battery within a certain range.

2. 2. The gas suppression device for a lithium-sulfur battery according to claim 1, wherein the control unit compares the voltage measured by the voltage measurement unit with a preset reference voltage, and when the voltage measured by the voltage measurement unit is less than the reference voltage, controls the current application unit to apply a current to the lithium-sulfur battery.

3. The battery further includes a storage unit for storing the lithium-sulfur battery, and a temperature measuring unit for measuring a temperature in the storage unit, The gas suppression device for a lithium-sulfur battery according to claim 1 , wherein the control unit adjusts a voltage measurement period of the voltage measurement unit in accordance with a temperature measured by the temperature measurement unit.

4. 2. The gas suppression device for a lithium-sulfur battery according to claim 1, further comprising: a housing for housing the lithium-sulfur battery; and a temperature control unit for controlling a temperature inside the housing.

5. 5. The gas suppression device for a lithium-sulfur battery according to claim 1, wherein the current application unit is controlled to apply a current of 0.01 C or less to the lithium-sulfur battery.

6. 2. The gas suppression device for a lithium-sulfur battery according to claim 1, wherein the lithium-sulfur battery has not been activated for more than 24 hours.

7. 2. The gas suppression device for a lithium-sulfur battery according to claim 1, wherein the lithium-sulfur battery is charged to an SOC of 90% or more.

8. A method for suppressing gas in a lithium-sulfur battery that has undergone an activation step, comprising: a voltage measurement stage for measuring a voltage of the lithium-sulfur battery; a control step of controlling the application of current so that the voltage of the lithium-sulfur battery is maintained within a certain range based on the result of the voltage measurement; and applying a current according to control so that the voltage of the lithium-sulfur battery is maintained within a certain range.

9. 9. The method of claim 8, wherein the controlling step compares the voltage measured in the voltage measuring step with a preset reference voltage, and when the measured voltage is less than the reference voltage, controls to apply a current to the lithium-sulfur battery.

10. the lithium-sulfur battery is housed in a housing; Further comprising measuring the temperature of the storage section; 9. The method of claim 8, wherein the voltage measurement step adjusts a voltage measurement period depending on the measured temperature of the storage portion.

11. The method of claim 10, further comprising adjusting the temperature in the storage compartment in response to the measured temperature.

12. 12. The method of claim 8, wherein the current applying step applies a current of 0.01 C or less.

13. The lithium-sulfur battery is housed in a battery case, 9. The method of claim 8, wherein the current is applied so that the volume change of the battery case is 1% or less.

14. 9. The method of claim 8, wherein the activation step comprises charging and discharging the lithium-sulfur battery at least once.

15. 9. The method of claim 8, wherein the activation step comprises charging and discharging the lithium-sulfur battery at a current of 0.02 C to 5 C.

16. 9. The method of claim 8, wherein the lithium-sulfur battery is one from which gas generated during the activation step has been removed.

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