Method and device for measuring remaining amount of liquid in liquid storage container

Abstract

The present invention is a method for measuring the remaining amount of a liquid in a liquid storage container, the method comprising the steps of: discharging the liquid in the liquid storage container to the outside through a suction tube inserted into the liquid storage container; the size or number of bubbles contained in the liquid penetrating through the light-transmitting part is observed through a visual device pointing to the light-transmitting part of the suction pipe; and estimating the remaining amount of the liquid based on the observed size and number of bubbles. Further, the method includes a remaining amount estimation step using the return ultrasonic waves, and the remaining amount estimation step using the return ultrasonic waves includes the steps of: oscillating the ultrasonic waves from the ultrasonic generator into the interior of the liquid storage container; receiving the ultrasonic wave returned after oscillation and analyzing the waveform of the ultrasonic wave; and estimating the remaining amount of the liquid by comparing the waveform of the ultrasonic wave with previously provided reference data.

Description

Technical Field

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2022-0095708, filed on August 1, 2022, which is hereby incorporated by reference in its entirety.

[0002] The present invention relates to a method and apparatus for measuring the remaining amount of liquid in a liquid storage container, and more particularly, to a method and apparatus for measuring the remaining amount of liquid in a liquid storage container, which is capable of more accurately and quickly estimating and identifying the remaining amount of liquid in a liquid storage container whose interior is difficult to visually inspect. Background Art

[0003] Secondary batteries widely used in various digital devices and transportation tools such as vehicles can be repeatedly charged and discharged. Also, research and development are continuously being performed to increase efficiency and improve safety.

[0004] The secondary battery is manufactured in a structure in which an electrode assembly in which a positive electrode / separator / negative electrode is repeatedly stacked is accommodated in a case such as a can or a pouch, and then an electrolyte is injected into the case.

[0005] The electrolyte is injected into a liquid storage container such as a drum, and then stored and moved. Figure 1 As shown, which illustrates a cross-sectional view of electrolyte being discharged from a liquid storage container, the liquid storage container 1 is configured to have a cylindrical shape having a bottom surface 1a, a circumferential wall 1b and a top surface 1c, and in a vertically upright state, when a suction tube 3 enters through a hole defined in the top surface 1c and negative pressure is applied to the suction tube 3, the electrolyte 1 is discharged to the outside of the liquid storage container 1.

[0006] However, in order to maintain the physical and chemical stability of the electrolyte 1, the liquid storage container 1 storing the electrolyte is made of stainless steel. Therefore, there is a problem in that it is difficult to visually check the remaining amount of the electrolyte inside the liquid storage container, that is, the height of the liquid level S from the outside.

[0007] In the prior art, during or when the discharge of the electrolyte is almost completed, the internal pressure of the liquid storage container 1 is increased to inject inert gas g into the liquid storage container 1 through the gas injection pipe 2 so as to minimize the remaining amount of the electrolyte.

[0008] However, the injection of the gas g may be started when the liquid level S of the electrolyte 1 drops below a certain reference, and when the liquid level S of the electrolyte drops below the suction pipe 3, the injection of the gas g is preferably stopped, but when the injection of the gas g is started too early and the injection of the gas g is stopped too late, bubbles P exist (see Figure 2 ) are introduced into the suction pipe 3 together.

[0009] In addition, when the electrolyte is injected into the housing of the secondary battery (such as measuring the electrolyte injection amount), the bubbles cause defects in the secondary battery. That is, when a small amount of electrolyte remains, the gas g is injected to ensure that the electrolyte is smoothly discharged into the liquid storage container, but when the gas g is introduced into the suction pipe 3, a motor or pump that generates negative pressure in the suction pipe 3 is connected to the suction pipe to cause idling of the motor or pump, which injects the electrolyte into the housing of the secondary battery, thereby causing a malfunction, and when the gas g introduced together with the electrolyte is introduced together with the housing of the secondary battery, a swelling phenomenon will occur in the secondary battery in the future.

[0010] Therefore, in order to prevent the inflow of the air bubbles P and the waste of the electrolyte, there is a need for a technical requirement for measuring the remaining amount in the liquid storage container 1 in which the electrolyte is stored. Summary of the invention

[0011] Technical issues

[0012] The main purpose of the present invention is to provide a method and device for measuring the remaining amount of liquid in a liquid storage container, which can quickly and accurately estimate or measure the remaining amount of electrolyte in the liquid storage container to meet the above technical needs. For reference, the "measurement" described here is not only used to measure the remaining amount of electrolyte (liquid), but also to predict and estimate how much electrolyte is left in the liquid storage container or whether the remaining amount has dropped below a predetermined standard value.

[0013] Technical Solution

[0014] The present invention for achieving the above-mentioned object includes a method and apparatus for measuring the remaining amount of liquid in a liquid storage container. In addition, the present invention provides a configuration for estimating (predicting or measuring) the remaining amount by monitoring bubbles contained in the discharged liquid (electrolyte), and provides an additional configuration that can be accomplished together with or separately from the above configuration, that is, a configuration for causing ultrasonic waves to oscillate inside the liquid storage container to estimate (predicting or measuring) the remaining amount based on the waveform of the ultrasonic carrier wave.

[0015] Among them, in a measuring method and a measuring device for monitoring bubbles contained in a discharged electrolyte to estimate the remaining amount, a light-transmitting portion is provided in a suction tube to observe the characteristics of the bubbles through the light-transmitting portion and estimate the remaining amount of the electrolyte based on the observed characteristics, and in the present invention, a measuring method and a measuring device having these technical features are provided as examples.

[0016] That is, in this embodiment, a method for measuring the remaining amount of liquid in a liquid storage container includes: discharging the liquid in the liquid storage container to the outside through a suction tube inserted into the liquid storage container; observing the size or number of bubbles contained in the liquid passing through the light-transmitting portion through a visual device that emits light toward the light-transmitting portion of the suction tube; and estimating the remaining amount of the liquid based on the observed size and number of bubbles.

[0017] In addition, the method may further include injecting gas into the liquid storage container after discharging the liquid within a predetermined range.

[0018] The liquid may be an electrolyte for a secondary battery, and the gas injected into the liquid storage container may be nitrogen.

[0019] The method may further include, when it is estimated that the estimated remaining amount of the liquid is less than a predetermined remaining amount, stopping the injection of the gas into the liquid storage container.

[0020] When observing the size of the bubbles or the number of the bubbles, light may be emitted from the lighting device toward the light transmitting portion.

[0021] A controller configured to estimate the remaining amount of liquid based on information received from a visual device can estimate the remaining amount of liquid in a machine learning manner, in which the correlation between the size and number of observed bubbles and the actual remaining amount of liquid is learned to estimate the remaining amount based on the learned data.

[0022] In addition, the controller configured to estimate the remaining amount of the liquid based on the information received from the vision device may compare the size and number of the observed bubbles with previously provided reference data to estimate the remaining amount of the liquid.

[0023] In addition, the method may further include estimating the remaining amount using an ultrasonic carrier wave. Estimating the remaining amount using an ultrasonic carrier wave may include: oscillating ultrasonic waves from an ultrasonic generator into the interior of the liquid storage container; receiving ultrasonic waves returned after the oscillation to analyze the waveform of the ultrasonic waves; and comparing the waveform of the ultrasonic waves with previously provided reference data to estimate the remaining amount of the liquid.

[0024] The ultrasonic generator may be in close contact with the center of the outer surface of the bottom of the liquid storage container or in close contact with the circumferential wall of the liquid storage container.

[0025] The estimation of the remaining amount using the ultrasonic carrier wave may be performed before the liquid in the liquid storage container is discharged to the outside through the suction tube or after the remaining amount of the liquid is estimated by observing the size and number of bubbles.

[0026] Furthermore, the present invention provides a measuring device capable of measuring the remaining amount by determining the state of the air bubbles as described above.

[0027] A device for measuring the remaining amount of liquid in a liquid storage container provided in the present invention includes: a liquid storage container, in which liquid is stored; a suction tube, which is connected to the liquid storage container, through which the liquid is sucked and discharged, and the suction tube is provided with a light-transmitting portion, which is made of a transparent or translucent material; a visual device, which is directed to the light-transmitting portion; and a controller, which is configured to receive information about the size and number of bubbles from the visual device so as to estimate the remaining amount of the liquid.

[0028] The controller may be configured to output the information on the size and number of bubbles received from the visual device and the estimation result on the display device.

[0029] The apparatus may further include an illumination device configured to emit light toward the light transmitting portion.

[0030] The light transmitting portion may be provided in a predetermined section in the suction pipe, and provided in a section extending in a straight line from the outside of the liquid storage container.

[0031] Furthermore, the present invention provides a measuring method and apparatus in which ultrasonic waves are oscillated to estimate a remaining amount based on a waveform of an ultrasonic carrier wave.

[0032] A method for measuring the remaining amount of liquid in a liquid storage container includes: closely attaching an ultrasonic generator that generates ultrasonic waves to the outer surface of the liquid storage container; causing the ultrasonic waves from the ultrasonic generator to oscillate into the interior of the liquid storage container; receiving the ultrasonic waves that return after the oscillation to analyze the waveform of the ultrasonic waves; and comparing the waveform of the ultrasonic waves with previously provided reference data to estimate the remaining amount of the liquid.

[0033] In addition, the present invention provides a device for measuring the remaining amount of liquid in a liquid storage container, to which the above-mentioned method for measuring the remaining amount is applied. A device for measuring the remaining amount of liquid in a liquid storage container includes: a liquid storage container in which liquid is stored; an ultrasonic generator attached to the outer surface of the liquid storage container to oscillate ultrasonic waves toward the inside of the liquid storage container; an ultrasonic receiver configured to receive ultrasonic waves returned after being generated from the ultrasonic generator; and a controller configured to estimate the remaining amount of the liquid by comparing waveform information of the ultrasonic waves received from the ultrasonic receiver with previously provided reference data.

[0034] The ultrasonic receiver may be integrated with the ultrasonic generator, and the ultrasonic generator may be configured to oscillate ultrasonic waves, receive returned ultrasonic waves, and transmit waveform information of the received ultrasonic waves to the controller.

[0035] The ultrasonic generator may be attached to the center of the outer surface of the bottom of the liquid storage container or to the circumferential wall of the liquid storage container.

[0036] Beneficial Effects

[0037] The present invention having the above-mentioned configuration can determine the remaining amount of liquid (electrolyte) in the liquid storage container in real time, and therefore, can more accurately determine the input and stop time points and the input amount of gas injected into the liquid storage container to solve the conventional problem that the motor and pump fail and bubbles are introduced into the housing of the secondary battery.

[0038] According to the present invention, the remaining amount can be estimated by observing the size and number of bubbles passing through the suction tube so as not to affect the flow rate of the electrolyte and not to cause physical and / or chemical changes or effects on the electrolyte. In addition, since there is no need to introduce a separate measuring device into the liquid storage container, the inflow of foreign matter can be fundamentally prevented.

[0039] When observing bubbles at the light-transmitting portion, additional light may be irradiated from the lighting device to observe the size and number of bubbles through more accurate image data.

[0040] In the present invention, the controller can estimate the remaining amount of liquid more quickly by comparing the size and number of observed bubbles with previously provided reference data.

[0041] Alternatively, the controller may estimate the remaining amount of liquid using a machine learning method that learns by comparing and analyzing the correlation between the size and number of observed bubbles and the actual remaining amount of liquid, and estimates the remaining amount of liquid based on the learned data, and thus, even when physical properties change or the size of the liquid storage container changes, the variables can be taken into account to estimate the remaining amount of liquid.

[0042] Furthermore, in the present invention, the remaining amount of the electrolyte can be estimated using an ultrasonic carrier wave. Therefore, by performing the method for estimating the remaining amount by observing bubbles, the remaining amount of the electrolyte can be measured more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a cross-sectional view illustrating a state in which the electrolytic solution is discharged from the liquid storage container.

[0044] Figure 21 is a view illustrating a state in which a visual device and an illumination device are provided to observe the size and number of bubbles through a light-transmitting portion of a suction tube, and the visual device is connected to a controller.

[0045] Figure 3 is a view illustrating a state in which an ultrasonic generator is attached to an outer bottom surface of a liquid storage container and connected to a controller.

[0046] Figure 4 is a view illustrating a state in which an ultrasonic generator is attached to an outer circumferential wall of a liquid storage container and connected to a controller.

[0047] Figure 5 is a view illustrating a state in which a visual device and a lighting device are provided to observe the size and number of bubbles through a light-transmitting portion of a suction tube, an ultrasonic generator is attached to an outer circumferential surface of a liquid storage container, and each of the visual device and the ultrasonic generator is connected to the same controller. DETAILED DESCRIPTION

[0048] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that the technical concept of the present invention can be easily performed by a person skilled in the art to which the present invention belongs. However, the present invention can be embodied in different forms and should not be construed as being limited to the embodiments set forth herein.

[0049] In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or like components throughout the specification.

[0050] Furthermore, the terms or words used in the present specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention on the basis of the principle that the inventor can appropriately define the concepts of the terms in order to best describe and interpret his or her invention.

[0051] The present invention relates to a method and an apparatus for measuring the remaining amount of an electrolyte 1 in a liquid storage container 10.

[0052] The present invention provides a configuration for estimating the remaining amount by monitoring the bubbles P contained in the discharged liquid electrolyte as a first embodiment, and provides an additional configuration performed together with or separately from the first embodiment, that is, a configuration for oscillating ultrasonic waves into a liquid storage container and estimating the remaining amount based on the waveform of the ultrasonic carrier, as a second embodiment. Hereinafter, the embodiments will be described in more detail with reference to the accompanying drawings.

[0053] First embodiment

[0054] The present invention provides a method and apparatus for estimating a remaining amount by monitoring bubbles P contained in a discharged electrolyte solution 1 as a first embodiment.

[0055] Figure 2 is a view illustrating a state in which a visual device 40 and an illumination device 41 are provided to observe the size and number of bubbles P through the light-transmitting portion 31 of the suction tube 30 , and the visual device 40 is connected to the controller 50 .

[0056] refer to Figure 2 , the apparatus for measuring the remaining amount of liquid in a liquid storage container provided in this embodiment includes a liquid storage container 10 in which liquid is stored, a suction tube 30 , a visual device 40 , and a controller 50 .

[0057] The liquid storage container 10 has a cylindrical shape having a bottom surface 10a, a circumferential wall 10b vertically standing along the circumference of the bottom surface 10a, and a top surface 10c covering the upper side of the opening of the circumferential wall 10b. In addition, at least two holes are perforated in the top surface 10c, and a gas injection pipe 20 and a suction pipe 30 are coupled to the holes, respectively, through which a gas g is injected into the liquid storage container, and through which an electrolyte is sucked from the liquid storage container 10 and then discharged to the outside.

[0058] The gas injection pipe 20 does not protrude into the liquid storage container 10 or protrudes only by a small length, but the suction pipe 30 has an end portion disposed close to the bottom surface 10 a to maximize suction of the electrolyte stored in the liquid storage container 10 .

[0059] The bottom surface 10 a may be set as a spherical surface, and the end of the suction pipe 30 may be set as low as possible at a slightly distant distance from the center of the spherical surface.

[0060] As described above, one side of the suction tube 30 is placed on the bottom surface 10a inside the liquid storage container 10, and the other side of the suction tube 30 is connected to a separate storage facility or an injection device for injecting electrolyte to suck the electrolyte 1 stored in the liquid storage container 10 and then allow the electrolyte 1 to move to the storage facility or the injection device.

[0061] The suction pipe 30 is provided with a light-transmitting portion 31 made of a transparent or translucent material (preferably a transparent material) at a portion spaced apart from the liquid storage container 10 so as to be exposed to the outside.

[0062] The light-transmitting portion 31 may be provided in a predetermined section of the suction tube 30, but may be provided not only at one position but also at two or more positions spaced apart from each other. In addition, the position is not particularly limited, but is provided in a section extending in a straight line from the outside of the liquid storage container 10 so that more accurate optical information is obtained when the visual device 40 optically senses the bubbles P.

[0063] The visual device 40 may use a camera, an optical sensor, or the like, which is capable of obtaining an optical image or an image having the number and / or size of the bubbles P contained in the electrode to move together when the electrolyte moves.

[0064] The visual device 40 transmits the acquired image information to the controller 50. In addition, an illumination device 41 that emits light toward the light transmitting portion 31 may be added according to the lighting conditions around the light transmitting portion 31.

[0065] The image information about the size and number of bubbles P transmitted from the visual device 40 is transmitted to the controller 50, and then, the controller 50 analyzes the received image information to estimate the remaining amount of the electrolyte inside the liquid storage container 10 or the height of the liquid surface S of the electrolyte. That is, when the liquid surface S of the electrolyte 1 drops below the end of the suction pipe 30, the air and the gas g are sucked into the suction pipe 30 together with the electrolyte. Here, the air and the gas g pass through the light-transmitting portion 31 in the form of bubbles P while the electrolyte flows. Therefore, the height of the liquid surface S of the electrolyte can be estimated by the size and number of the bubbles P, and therefore, the remaining amount can also be estimated.

[0066] Therefore, the measuring device has a configuration in which a portion of the suction tube 30 is transparent to provide a light-transmitting portion 31, and the state of the bubbles P is determined to estimate the remaining amount through the light-transmitting portion 31. For reference, when the size of each bubble P is small, the sensing performance can be improved by additionally irradiating the light 41 or increasing the resolution of the captured image.

[0067] The controller 50 may be configured to output the information on the size and number of bubbles received from the visual device 40 and the estimation result on a display device (not shown) so that a worker and a manager can determine the remaining amount and the measurement status.

[0068] In addition, the controller 50 may be configured to compare the size and number of the observed bubbles with previously provided reference data in order to estimate the remaining amount of the liquid (electrolyte). Alternatively, the controller may be configured to estimate the remaining amount of the liquid in a machine learning manner, in which the correlation between the size and number of the observed bubbles and the actual remaining amount of the liquid is compared and analyzed for learning, and then, the remaining amount is estimated based on the learned data.

[0069] This embodiment provides a measurement method using the measurement device having the above-described configuration.

[0070] The method for measuring the remaining amount of liquid in the liquid storage container 10 provided in this embodiment starts with a process of discharging the electrolyte stored in the liquid storage container to the outside through the suction pipe 30 .

[0071] As described above, the light transmitting portion 31 is provided on the suction tube 30 so that the visual device 40 performs a process of observing (sensing) the size or number of bubbles P contained in the electrolyte passing through the light transmitting portion 31 .

[0072] Then, a process of estimating the remaining amount of the liquid based on the size and number of the observed bubbles by the controller 50 receiving the image data from the vision device 40 is performed.

[0073] In addition, a process of injecting gas g into the liquid storage container after discharging the liquid within a predetermined range according to the remaining amount (i.e., the number of bubbles) may be additionally performed. Here, as described above, the liquid is an electrolyte for a secondary battery, and the gas injected into the liquid storage container is nitrogen, which does not chemically react with the electrolyte.

[0074] Furthermore, when the estimated remaining amount of the liquid is estimated to be lower than a predetermined remaining amount, a process of stopping the injection of the gas into the liquid storage container is performed.

[0075] Second embodiment

[0076] In addition, the present invention provides a measuring method and apparatus as a second embodiment, in which ultrasonic waves are oscillated to estimate the remaining amount based on the waveform of an ultrasonic carrier wave. The method using an ultrasonic carrier wave according to the second embodiment can be performed simultaneously with the measuring method according to the first embodiment, or separately before and after the measuring method according to the first embodiment, or instead of the measuring method according to the first embodiment.

[0077] Figure 3 is a view illustrating a state in which an ultrasonic generator 60 is attached to an outer bottom surface of a liquid storage container and connected to a controller, and Figure 4 1 is a view illustrating a state in which the ultrasonic generator 60 is attached to the outer circumferential wall 10 b of the liquid storage container and connected to the controller.

[0078] in addition, Figure 5 is a view illustrating a state in which a visual device 40 and a lighting device 41 are set to observe the size and number of bubbles through the light-transmitting portion 31 of the suction tube 30, an ultrasonic generator 60 is attached to the outer circumferential surface 10a of the liquid storage container 10, and each of the visual device and the ultrasonic generator is connected to the same controller 50.

[0079] Referring to the drawings, the apparatus for measuring the remaining amount of liquid in the liquid storage container 1 provided in this embodiment includes an ultrasonic generator 60, an ultrasonic receiver (not shown), and a controller 50, the ultrasonic generator 60 is attached to the outer surface (bottom surface or circumferential wall) of the liquid storage container in which the liquid is stored so that the ultrasonic wave oscillates toward the inside of the liquid storage container, the ultrasonic receiver receives the ultrasonic wave returned after being generated from the ultrasonic generator 60, and the controller 50 estimates the remaining amount of the liquid by comparing the waveform information of the ultrasonic wave received from the ultrasonic receiver with the previously provided reference data. Here, the controller 50 may be the controller 50 provided in the first embodiment, or may be provided separately.

[0080] That is, in the ultrasonic wave oscillating toward the inside of the liquid storage container 10, "the carrier wave u1 reflected from the liquid surface S of the electrolyte l'" and "the carrier wave u2 reflected from the inner wall (top surface, circumference, etc.) of the liquid storage container 10 after passing through the liquid surface S of the electrolyte l'" have different amplitudes, phases, frequencies, periods, etc. from each other to change in waveform. That is, the ultrasonic wave reacts differently when passing through the liquid medium and when passing through the gas (air) medium, resulting in a change in waveform. Therefore, the height of the liquid surface S of the electrolyte can be determined by the difference in the waveforms of the carrier waves u1 and u2 or the change in the characteristics of the carrier wave u3 according to the installation position of the ultrasonic generator 60.

[0081] The ultrasonic receiver may be integrated with the ultrasonic generator 60 , and the ultrasonic generator 60 may oscillate ultrasonic waves and receive returned ultrasonic waves to transmit waveform information of the received ultrasonic waves to the controller 50 .

[0082] The ultrasonic generator 60 can be Figure 3 and Figure 5 As shown, the bottom surface 10a of the liquid storage container 10 may be attached to the center of the outside, or may be attached as shown. Figure 4 It is shown attached to the circumferential wall 10b of the liquid storage container 10a.

[0083] Furthermore, the present embodiment provides a measurement method using the measurement device having the above-described configuration.

[0084] A method for measuring the remaining amount of liquid in a liquid storage container using ultrasonic waves includes: a process of closely attaching an ultrasonic generator 60 that generates ultrasonic waves to the outer surface of the liquid storage container; a process of oscillating the ultrasonic waves from the ultrasonic generator 60 to the inside of the liquid storage container 10; a process of receiving the ultrasonic waves that return after the oscillation to analyze the waveform of the ultrasonic waves; and a process of comparing the waveform of the ultrasonic waves with previously provided reference data to estimate the remaining amount of the liquid.

[0085] Here, the ultrasonic receiver may be integrated into the ultrasonic generator, and two or more ultrasonic receivers may be attached to the liquid storage container to further improve the estimation accuracy by separately analyzing the waveforms of ultrasonic waves at different points. For example, the ultrasonic generator with which the ultrasonic receiver is integrated may be in close contact with the center of the outside of the bottom surface 10a of the liquid storage container, and may also be in close contact with the circumferential wall 10b of the liquid storage container.

[0086] The process of estimating the remaining amount using the carrier wave of ultrasonic waves may be performed before the process of discharging the liquid in the liquid storage container to the outside through the suction pipe 30 or after the process of estimating the remaining amount of the liquid by observing the size and number of bubbles.

[0087] That is, the apparatus for measuring the remaining amount using ultrasonic waves provided in the second embodiment may be installed together with the device for measuring the remaining amount provided in the first embodiment, such as Figure 5 In addition, the method of measuring the remaining amount using ultrasonic waves provided in the second embodiment may be performed simultaneously with the method of measuring the remaining amount provided in the first embodiment, or may be performed sequentially with a certain time difference.

[0088] In this case, the controller 50 may be configured to be connected to the vision device 40, the ultrasonic generator 60, and the ultrasonic receiver to receive all ultrasonic waveform information and bubble information, thereby finally estimating the remaining amount by synthesizing the two pieces of information.

[0089] Furthermore, in some cases, only one of the method for measuring the remaining amount provided in the first embodiment and the method for measuring the remaining amount provided in the second embodiment may be implemented.

[0090] The present invention having the above-mentioned configuration can determine the remaining amount of liquid (electrolyte) in the liquid storage container in real time, and therefore, can more accurately determine the input and stop time points and the input amount of gas injected into the liquid storage container to solve the conventional problem that the motor and pump fail and bubbles are introduced into the housing of the secondary battery.

[0091] According to the present invention, the remaining amount can be estimated by observing the size and number of bubbles passing through the suction tube so as not to affect the flow rate of the electrolyte and not to cause physical and / or chemical changes or effects on the electrolyte. In addition, since there is no need to introduce a separate measuring device into the liquid storage container, the inflow of foreign matter can be fundamentally prevented.

[0092] When observing bubbles at the light-transmitting portion, additional light may be irradiated from the lighting device to observe the size and number of bubbles through more accurate image data.

[0093] In the present invention, the controller can estimate the remaining amount of liquid more quickly by comparing the size and number of observed bubbles with previously provided reference data.

[0094] Alternatively, the controller may estimate the remaining amount of liquid using a machine learning method that learns by comparing and analyzing the correlation between the size and number of observed bubbles and the actual remaining amount of liquid, and estimates the remaining amount of liquid based on the learned data, and thus, even when the physical properties change or the size of the liquid storage container changes, these variables can be taken into account to estimate the remaining amount of liquid.

[0095] Furthermore, in the present invention, the remaining amount of the electrolyte can be estimated using an ultrasonic carrier wave. Therefore, by performing the method for estimating the remaining amount by observing bubbles, the remaining amount of the electrolyte can be measured more accurately.

[0096] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

[0097] [Description of Reference Signs]

[0098] 10: Liquid storage container

[0099] 20: Gas injection pipe

[0100] 30: Suction tube

[0101] 31: light-transmitting part

[0102] 40: Visual Installation

[0103] 41: Lighting device

[0104] 50: Controller

[0105] 60: Ultrasonic generator

Claims

1. A method for measuring the remaining amount of liquid in a liquid storage container, the method comprising: discharging the liquid in the liquid storage container to the outside through a suction tube inserted into the liquid storage container; observing the size or number of bubbles contained in the liquid passing through the light-transmitting portion of the suction tube by a visual device that emits light toward the light-transmitting portion of the suction tube; as well as The remaining amount of liquid is estimated based on the size and number of bubbles observed. 2 . The method according to claim 1 , further comprising injecting a gas into the liquid storage container after discharging the liquid within a predetermined range.

3. The method according to claim 2, wherein the liquid is an electrolyte for a secondary battery, and The gas injected into the liquid storage container is nitrogen.

4. The method according to claim 2, further comprising: When the estimated remaining amount of the liquid is estimated to be less than a predetermined remaining amount, injection of the gas into the liquid storage container is stopped.

5. The method according to claim 1, wherein: When observing the size of the bubbles or the number of the bubbles, light is emitted from the lighting device toward the light transmitting portion.

6. The method according to claim 1, wherein: A controller configured to estimate the remaining amount of liquid based on information received from the visual device estimates the remaining amount of liquid in a machine learning manner, in which the correlation between the size and number of observed bubbles and the actual remaining amount of liquid is learned to estimate the remaining amount based on the learned data.

7. The method according to claim 1, wherein: The controller, configured to estimate the remaining amount of liquid based on information received from the visual device, compares the size and number of observed bubbles with previously provided reference data to estimate the remaining amount of liquid.

8. The method according to any one of claims 1 to 7, further comprising estimating the remaining amount using an ultrasonic carrier wave, Wherein estimating the remaining amount using the ultrasonic carrier wave comprises: causing ultrasonic waves from an ultrasonic generator to vibrate into the interior of the liquid storage container; receiving the ultrasonic wave returned after the oscillation to analyze the waveform of the ultrasonic wave; as well as The waveform of the ultrasonic wave is compared with previously provided reference data to estimate the remaining amount of liquid. 9 . The method according to claim 8 , wherein the ultrasonic generator is in close contact with the center of the outer surface of the bottom of the liquid storage container or in close contact with the circumferential wall of the liquid storage container.

10. The method according to claim 8, wherein: Before the liquid in the liquid storage container is discharged to the outside through the suction tube, the estimation of the remaining amount using the ultrasonic carrier wave is performed.

11. The method according to claim 8, wherein: After estimating the remaining amount of liquid by the size and number of the observed bubbles, the estimation of the remaining amount using the ultrasonic carrier wave is performed.

12. A device for measuring the remaining amount of liquid in a liquid storage container, the device comprising: a liquid storage container in which liquid is stored; a suction pipe connected to the liquid storage container, through which the liquid is sucked and discharged, and provided with a light-transmitting portion made of a transparent or translucent material; A visual device, the visual device is directed toward the light-transmitting portion; as well as A controller is configured to receive information about the size and number of bubbles from the visual device in order to estimate the remaining amount of liquid.

13. The device according to claim 12, wherein: The controller is configured to output the information on the size and number of bubbles received from the visual device and the estimation result on the display device. The apparatus according to claim 13 , further comprising an illumination device configured to emit light toward the light-transmitting portion.

15. The apparatus according to claim 13, wherein: The light transmitting portion is provided in a predetermined section in the suction pipe and is provided in a section extending in a straight line from the outside of the liquid storage container.

16. A method for measuring a remaining amount of liquid in a liquid storage container, the method comprising: closely attaching an ultrasonic generator for generating ultrasonic waves to an outer surface of the liquid storage container; causing the ultrasonic wave from the ultrasonic generator to vibrate into the interior of the liquid storage container; receiving the ultrasonic wave returned after the oscillation to analyze the waveform of the ultrasonic wave; and The waveform of the ultrasonic wave is compared with previously provided reference data to estimate the remaining amount of liquid.

17. A device for measuring the remaining amount of liquid in the liquid storage container, the device comprising: a liquid storage container in which liquid is stored; an ultrasonic generator attached to an outer surface of the liquid storage container to oscillate ultrasonic waves toward the inside of the liquid storage container; an ultrasonic receiver configured to receive the ultrasonic wave returned after being generated from the ultrasonic generator; as well as A controller is configured to estimate the remaining amount of the liquid by comparing waveform information of the ultrasonic wave received from the ultrasonic receiver with previously provided reference data.

18. The apparatus according to claim 17, wherein the ultrasonic receiver is integrated with the ultrasonic generator, and the ultrasonic generator is configured to oscillate the ultrasonic wave, receive the returned ultrasonic wave, and transmit waveform information of the received ultrasonic wave to the controller.

19. The apparatus of claim 18, wherein the ultrasonic generator is attached to the center of an outer surface of a bottom of the liquid storage container.

20. The apparatus of claim 18, wherein the ultrasonic generator is attached to a circumferential wall of the liquid storage container.

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