Battery cell fixture including a spacer laminate, device for measuring the volume of a battery cell including the battery cell fixture, and method for measuring the volume of a battery cell using the device

Abstract

The present technology relates to a battery cell jig including a spacer laminate, a battery cell volume measuring device including the battery cell jig, and a battery cell volume measuring method performed by using the device. By including spacers that can be assembled into a spacer laminate, the space between a first plate and a second plate between which a battery cell is interposed can be easily adjusted. In addition, by including a slit unit that is open along a longitudinal direction in the spacer, water can be prevented from staying in the space between the battery cell jig and the spacer when measuring a volume change of the battery cell.

Description

Technical Field

[0001] This application claims priority based on Korean Patent Application No. 10-2020-0143327, filed on October 30, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery cell fixture including a spacer laminate, a battery cell volume measuring device including the battery cell fixture, and a battery cell volume measuring method performed by using the device. Background Art

[0003] Recently, rechargeable secondary batteries have been widely used as an energy source for wireless mobile devices. In addition, secondary batteries have received attention as an energy source for electric vehicles, hybrid electric vehicles, etc., which are proposed as solutions to air pollution of existing gasoline vehicles and diesel vehicles using fossil fuels. Therefore, due to the advantages of secondary batteries, the types of applications using secondary batteries are currently very diverse, and it is expected that secondary batteries will be applied to many fields and products in the future.

[0004] Depending on the composition of the electrodes and the electrolyte, such secondary batteries can be classified as lithium-ion batteries, lithium-ion polymer batteries, lithium polymer batteries, etc. Among them, the use of lithium-ion polymer batteries, which are less likely to leak electrolytes and are easy to manufacture, is increasing. Generally, depending on the shape of the battery case, secondary batteries are classified into: cylindrical batteries and prismatic batteries, in which the electrode assembly is embedded in a cylindrical or rectangular metal can; and pouch-type batteries, in which the electrode assembly is embedded in a pouch-shaped case made of an aluminum laminate. The electrode assembly built into the battery case is composed of a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and is a power generation element capable of charging and discharging. The electrode assembly is classified into: a jelly roll type, in which the jelly roll type is wound with the separator interposed between the positive electrode and the negative electrode, and the positive electrode and the negative electrode are long sheets coated with an active material; and a stacked type, in which a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked while the separator is interposed therebetween.

[0005] Here, as the battery capacity increases, the size of the case also increases, and the processing of thin materials has received attention. Therefore, the use of pouch-type batteries having a structure in which a stacked type or a stacked / folded type electrode assembly is built into a pouch-shaped battery case made of an aluminum laminate is gradually increasing due to low manufacturing cost, light weight, easy shape change, etc.

[0006] As a large amount of gas is generated by electrolyte decomposition due to repeated charging / discharging, such a secondary battery deteriorates, and this aspect varies depending on the battery design and usage type. When gas is continuously generated in the battery, an expansion phenomenon in which the battery volume increases is observed, and when the internal pressure of the battery cell exceeds the critical point, the battery may explode. Therefore, it is necessary to observe the volume change of the battery cell.

[0007] Traditionally, in order to observe the volume change of the battery cell, the Archimedes' principle is used to measure the amount of volume change of the battery cell. At this time, in order to squeeze the battery cell, the battery cell is accommodated in a battery cell fixture, and then an experiment is conducted. Figure 1 is a schematic diagram of a conventional battery cell fixture for evaluating the performance of a secondary battery, and Figure 2 is Figure 1 a right side cross-sectional view (A-A') of the battery cell fixture shown in Figure 1 As shown, the battery cell fixture 10 uses a nut 15 and a bolt 14 penetrating the first plate 12 and the second plate 13 to perform bolt fastening to fix the battery cell 11. In addition, since there is a problem that the pressure applied to the battery cell 11 varies depending on the fastening order of the bolt 14 and the nut 15 or the style of the worker, as Figure 2 shown, a method has been used to minimize the application of deviation pressure caused by position or fastening error by using a spacer adapted to the thickness of the battery cell 11.

[0008] However, when using the Archimedes' principle to measure the amount of volume change in a state where the battery cell 11 is accommodated in the battery cell fixture 10, inaccurate data may be obtained because water remains in the space between the battery cell fixture 10 and the spacer 16, which may cause corrosion of the bolt 14 and the battery cell fixture 10. Therefore, the volume of the battery cell should be measured after disassembling the battery cell fixture 10. SUMMARY OF THE INVENTION

[0009]

Technical Problem

[0010] The present invention is considered to solve at least some of the above problems. For example, an aspect of the present invention provides: a battery cell fixture including a spacer laminate, which can prevent water from remaining in the space between the battery cell fixture and the spacer when measuring the volume change of the battery cell; a battery cell volume measuring device including the battery cell fixture; and a battery cell volume measuring method performed by using the device.

[0011]

Technical Solution

[0012] The present invention provides a battery cell fixture including a spacer laminate. In one example, the battery cell fixture according to the present invention includes: a first plate and a second plate; a bolt and a nut that fix the first plate and the second plate in a state where a battery cell is interposed between the first plate and the second plate; and a spacer laminate that is located between the first plate and the second plate to specify a separation distance and is generated by laminating n spacers having a structure surrounding the bolt, where n is an integer equal to or greater than 2. At this time, each spacer includes a slit unit that is open along the longitudinal direction of the spacer.

[0013] In one example, the slit unit of the spacer is open from one side to the other side along the longitudinal direction of the spacer laminate. In addition, the slit unit of the spacer may be open within a range of 10 degrees to 70 degrees with respect to the axis center.

[0014] In another example, one end of the spacer has a protrusion or a recess, and the central region of the protrusion or the recess has protruded or recessed into a stepped structure. At this time, the other end of the spacer may have a protrusion or a recess, and the central region of the protrusion or the recess has protruded or recessed into a stepped structure. In a specific example, one end of the k-th spacer has a protrusion or a recess, and the other end of the (k + 1)-th spacer has a recess or a protrusion corresponding to the protrusion or the recess of the k-th spacer. Here, k is an integer equal to or greater than 1 and equal to or less than n - 1.

[0015] In yet another example, one end of the spacer has a bump or a groove, and the other end of the spacer has a groove or a bump. In a specific example, one end of the k-th spacer has a bump or a groove, and the other end of the (k + 1)-th spacer has a groove or a bump corresponding to the bump or the groove of the k-th spacer, and where k is an integer equal to or greater than 1 and equal to or less than n - 1.

[0016] In addition, the battery cell fixture may include 4 to 12 bolts and nuts respectively, and the spacer may be fastened by at least one bolt.

[0017] In addition, the present invention provides a battery cell volume measuring device including the above battery cell fixture. In one example, the device for measuring the volume of a battery cell according to the present invention includes: a battery cell fixture; a water tank in which a liquid is accommodated; and a scale that measures the weights of the battery cell fixture with a battery cell accommodated therein outside and inside the water tank respectively. In a specific example, the battery cell volume measuring device further includes a charge and discharge unit that is electrically connected to the battery cell.

[0018] In addition, the present invention provides a method for measuring the volume of a battery cell by using the above battery cell volume measuring device. In one example, the method for measuring the volume of a battery cell according to the present invention is performed by placing the battery cell between battery cell jigs and then measuring the weights before and after the volume change of the battery cell, respectively.

[0019] In a specific example, the method includes: placing the battery cell between battery cell jigs, and then measuring the weight of the battery cell jig in air; placing the battery cell jig in a water tank that already contains liquid, and then measuring the weight of the battery cell jig in the liquid; and calculating the volume after the volume change of the battery cell by the following formula 1:

[0020]

Formula 1

[0021]

[0022] Here, V represents the volume after the volume change of the battery cell, Wl represents the weight of the battery cell jig in air, W2 represents the weight of the battery cell jig contained in the liquid, and ρ represents the density of the liquid.

[0023] At this time, the method further includes: charging and discharging the battery cell during the measurement of the weight of the battery cell jig contained in the liquid.

[0024] In addition, during the measurement of the weight of the battery cell jig in air and the measurement of the weight of the battery cell jig in the liquid, the weight of the battery cell jig can be measured by using a spring scale.

[0025] In another example, the method further includes: heating the liquid to a predetermined temperature during the measurement of the weight of the battery cell jig contained in the liquid. At this time, calculating the volume after the volume change of the battery cell includes: calculating the volume change of the battery cell according to the temperature of the liquid.

[0026]

Advantageous Effects

[0027] According to the battery cell jig including a spacer laminate, the battery cell volume measuring device including the battery cell jig, and the battery cell volume measuring method performed by using the device according to the present invention, by including spacers that can be assembled into a spacer laminate, the space between the first plate and the second plate with the battery cell interposed therebetween can be easily adjusted. In addition, by including a slit unit that is open along the longitudinal direction in the spacer, when measuring the volume change of the battery cell, water can be prevented from remaining in the space between the battery cell jig and the spacer. Description of the Drawings

[0028] Figure 1It is a schematic diagram of a conventional battery cell fixture for evaluating the performance of a secondary battery.

[0029] Figure 2 Is Figure 1 A right side cross-sectional view (A-A') of the battery cell fixture shown in

[0030] Figure 3 It is a cross-sectional view of a battery cell fixture including a spacer laminate according to an embodiment of the present invention.

[0031] Figure 4 It is a schematic diagram showing the spacer laminate in the battery cell fixture according to an embodiment of the present invention.

[0032] Figure 5 It is a cross-sectional view of a battery cell fixture including a spacer laminate according to another embodiment of the present invention.

[0033] Figure 6 It is a schematic diagram showing the spacer in the battery cell fixture according to another embodiment of the present invention.

[0034] Figure 7 It is a schematic diagram showing the spacer laminate in the battery cell fixture according to another embodiment of the present invention.

[0035] Figure 8 It is a cross-sectional view of a battery cell fixture including a spacer laminate according to another embodiment of the present invention.

[0036] Figure 9 It is a schematic diagram showing the spacer in the battery cell fixture according to another embodiment of the present invention.

[0037] Figure 10 It is a schematic diagram showing the spacer laminate in the battery cell fixture according to another embodiment of the present invention.

[0038] Figure 11 It is a view showing each component of a battery cell volume measuring device according to still another embodiment of the present invention.

[0039] Figure 12 It is a flowchart showing a method of measuring the volume of a battery cell according to still another embodiment of the present invention. Detailed Description

[0040] Since the inventive concept of the present invention allows for various variations and numerous embodiments, specific embodiments will be shown in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific forms disclosed, and it should be understood to include all variations, equivalent forms, and alternative forms within the spirit and scope of the present invention.

[0041] In the present application, it should be understood that terms such as "including" or "having" are intended to indicate the presence of the features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, and these terms do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts, or combinations thereof. Moreover, when a part such as a layer, film, region, plate, etc. is referred to as being "on" another part, this includes not only the case where the part is "directly on" the other part, but also the case where another part is interposed therebetween. On the other hand, when a part such as a layer, film, region, plate, etc. is referred to as being "under" another part, this includes not only the case where the part is "directly under" the other part, but also the case where another part is interposed therebetween. In addition, "disposed on..." in the present application may include the cases of being disposed at the bottom and at the top.

[0042] The present invention provides a battery cell fixture including a spacer laminate, a battery cell volume measuring device including the battery cell fixture, and a battery cell volume measuring method performed by using the device.

[0043] Traditionally, the Archimedes' principle has been used to measure the volume change of a battery cell. At this time, in order to squeeze the battery cell, the battery cell is accommodated in the battery cell fixture to perform an experiment, and in order to squeeze the battery cell accommodated in the battery cell fixture with a uniform pressure, a spacer corresponding to the thickness of the battery cell is used to minimize the deviation pressure caused by position and fastening errors. However, when the volume change is measured using the Archimedes' principle in a state where the battery cell is accommodated in the battery cell fixture, inaccurate data may be obtained because water remains in the space between the battery cell fixture and the spacer, which may cause corrosion of the bolts and the battery cell fixture. Therefore, the volume of the battery cell should be measured after disassembling the battery cell fixture.

[0044] Therefore, the present invention provides: a battery cell fixture including a spacer laminate, which can prevent water from remaining in the space between the battery cell fixture and the spacer when measuring the volume change of the battery cell; a battery cell volume measuring device including the battery cell fixture; and a battery cell volume measuring method performed by using the device.

[0045] Specifically, the battery cell fixture including a spacer laminate, the battery cell volume measuring device including the battery cell fixture, and the battery cell volume measuring method performed by using the device can easily adjust the space between the first plate and the second plate with the battery cell interposed therebetween by including a spacer laminate formed by laminating spacers. In addition, by including a slit unit that is open along the longitudinal direction in the spacer, when measuring the volume change of the battery cell, it is possible to prevent water from staying in the space between the battery cell fixture and the spacer.

[0046] In one embodiment, the present invention provides a battery cell fixture including a spacer laminate. In a specific example, the battery cell fixture according to the present invention includes: a first plate and a second plate; a bolt and a nut that fix the first plate and the second plate in a state where the battery cell is interposed between the first plate and the second plate; and a spacer laminate that is located between the first plate and the second plate to specify a separation distance, and the spacer laminate is formed by laminating n spacers having a structure surrounding the bolt, where n is an integer equal to or greater than 2. At this time, each spacer includes a slit unit that is open along the longitudinal direction of the spacer.

[0047] In the present invention, the "slit unit" refers to a gap formed along the longitudinal direction in the spacer and means an open area formed along the longitudinal direction of the spacer. In particular, since the battery cell fixture according to the present invention includes a slit unit in the spacer, when measuring the volume change of the battery cell using Archimedes' principle, it is possible to prevent water or gas from staying in the space.

[0048] In an example, the battery cell fixture according to the present invention includes a spacer that includes a slit unit open along the longitudinal direction. The spacer is used to keep the distance between the first plate and the second plate constant and has a structure surrounding the bolt. The spacer can be made of aluminum.

[0049] In addition, the slit unit may be open from one side to the other along the longitudinal direction of the spacer. Specifically, the slit unit may be open from one side to the other along the longitudinal direction of the spacer laminate formed by laminating n spacers.

[0050] In a specific example, when observed based on a cross-section, the spacer has a "C" shape. Through the slit unit of such a spacer, when measuring the volume of the battery cell using Archimedes' principle, it is possible to prevent water from staying in the spacer or prevent gas from filling the spacer.

[0051] In one example, the slit unit of the spacer can be open within a range of 10 degrees to 70 degrees with respect to the central axis. In a specific example, based on the cross-section of the spacer, the slit unit of the spacer is open within a range of 10 degrees to 70 degrees with respect to the central axis. For example, based on the axis of the spacer, the slit unit can be open within a range of 20 degrees to 70 degrees, 30 degrees to 70 degrees, or 40 degrees to 70 degrees, or can be open at an average of 60 degrees. Since the slit unit is open at the above angles, it is possible to prevent water from staying in the space between the battery cell fixture and the spacer or prevent gas from filling in this space.

[0052] In addition, when measuring the volume change of the battery cell using Archimedes' principle, since the spacer is open at the above angles, the volume change of the battery cell can be measured after separating the spacer from the battery cell fixture.

[0053] In one example, in the battery cell fixture according to the present invention, the spacer laminate has a structure obtained by laminating n spacers (n is an integer equal to or greater than 2). Herein, n can be an integer within a range of 2 to 10, 2 to 8, 2 to 6, or 2 to 5, or can be 3. However, the present invention is not limited thereto. Conventionally, when a battery cell is between a first plate and a second plate, the pressure applied to the battery cell varies depending on the order of the fastening bolts and nuts or the inclination of the worker. However, in the present invention, since it is possible to laminate n spacers according to the height of the battery cell between the first plate and the second plate, it is possible to minimize the pressure imbalance due to the fastening position of the bolts and nuts or the fastening error of the bolts and nuts. In addition, n spacers (n is an integer equal to or greater than 2) are laminated to form a spacer laminate, and the height of the spacer laminate preferably corresponds to the height of the battery cell between the first plate and the second plate.

[0054] In one example, the spacer laminate is used to keep the distance between the first plate and the second plate constant and has a structure surrounding a predetermined area of the bolt. As described above, the height of the spacer laminate can correspond to the height of the battery cell between the first plate and the second plate. Therefore, it is possible to easily adjust the space between the first plate and the second plate. Specifically, the user allows the battery cell to be located at the second plate coupled to the bolt and allows the spacer to be inserted into the bolt. In addition, after laminating n spacers to allow the height of the battery cell to correspond to the height of the spacer laminate, the first plate can be coupled, and fastening can be performed with a nut.

[0055] In one example, the battery cell fixture according to the present invention includes a plurality of bolts and nuts. In a specific example, the battery cell fixture according to the present invention includes 4 to 12 or 6 to 10 bolts and nuts respectively. For example, the battery cell fixture includes 10 bolts and nuts respectively. In addition, the spacer can be fastened by at least one bolt. That is, each spacer is fastened to each of the plurality of bolts, and the spacers are fastened to have the same height. In addition, each bolt and nut can be fastened with the same pressure.

[0056] In addition, the n spacers constituting the spacer laminate may have the same height, or may have different heights. For example, the n spacers may be spacers with different heights. Since the n spacers constituting the spacer laminate have different heights, it is possible to more easily allow the height of the spacer laminate to correspond to the height of the battery cell.

[0057] In another example, one end of the spacer has a protrusion or a recess, the protrusion or the recess having a central region that has protruded or recessed into a stepped structure, and the other end of the spacer has a protrusion or a recess, the protrusion or the recess having a central region that has protruded or recessed into a stepped structure. Here, the stepped structure refers to a structure forming steps. Specifically, in the spacer laminate of the present invention, one end of the k-th spacer has a protrusion or a recess, and the other end of the (k + 1)-th spacer has a recess or a protrusion corresponding to the protrusion or the recess of the k-th spacer. Here, k is an integer equal to or greater than 1 and equal to or less than n - 1.

[0058] For example, one end of the spacer may have a protrusion having a central region that has protruded into a stepped structure, and the other end of the spacer may have a recess having a central region that has recessed into a stepped structure. In a specific example, in the spacer laminate of the present invention, one end of the k-th spacer has a protrusion, and the other end of the (k + 1)-th spacer has a recess corresponding to the protrusion of the k-th spacer. Here, k is an integer equal to or greater than 1 and equal to or less than n - 1. That is, the recess of the (k + 1)-th spacer can be laminated on the protrusion of the k-th spacer.

[0059] In yet another example, one end of the spacer has a bump or a groove, and the other end of the spacer has a groove or a bump. In addition, at least one bump or groove can be formed on one side or the other side of the spacer respectively.

[0060] Specifically, in the spacer laminate of the present invention, one end of the k-th spacer has a bump or a groove, and the other end of the (k + 1)-th spacer has a groove or a bump corresponding to the bump or the groove of the k-th spacer. Here, k is an integer equal to or greater than 1 and equal to or less than n - 1. In a specific example, in the spacer laminate of the present invention, one end of the k-th spacer has a bump, and the other end of the (k + 1)-th spacer has a groove corresponding to the bump of the k-th spacer. Here, k is an integer equal to or greater than 1 and equal to or less than n - 1. That is, by allowing the groove of the (k + 1)-th spacer to contact the bump of the k-th spacer, n spacers can be easily laminated.

[0061] In addition, when the (k + 1)-th spacer is laminated on the upper part of the k-th spacer, the bump and the groove can prevent the spacer from rotating in the axial direction and can easily adjust the space between the first plate and the second plate with the battery cell interposed therebetween.

[0062] In addition, the present invention provides a battery cell volume measuring device including the above-described battery cell fixture.

[0063] In one example, the device for measuring the volume of a battery cell according to the present invention includes: the battery cell fixture; a water tank in which a liquid is accommodated; and a scale that measures the weight of the battery cell fixture with the battery cell accommodated therein on the outside and on the inside of the water tank, respectively.

[0064] The device for measuring the volume of a battery cell according to the present invention uses Archimedes' principle. According to Archimedes' principle, the buoyant force applied to an object that is completely or partially immersed in a liquid acts in a direction opposite to the direction of gravity, and the magnitude of this buoyant force is the same as the weight of the liquid equivalent to the volume displaced by the object (F = ρgV = mg, where F: buoyant force, ρ: density of the liquid, V: volume of the object, equivalent to the amount immersed in the liquid, g: acceleration due to gravity, m: mass of the object). At this time, the difference between the weight of the battery cell before it is immersed in the liquid accommodated in the water tank and the weight of the battery cell after it is immersed in the liquid can be the weight of the liquid whose volume increases as the battery cell is immersed in the liquid. At this time, since the weight of the liquid displaced as the battery cell is immersed in the liquid is the same as the buoyant force, the volume of the battery cell can be identified based on the measured buoyant force. That is, if the weight of the battery cell in the air and the weight of the battery cell in the liquid are obtained, the volume of the battery cell can be calculated.

[0065] Similarly, with the battery cell volume measuring device according to the present invention, by only measuring the weight of the battery cell without the process of stamping or squeezing the battery, the volume of the battery cell can be measured in a non-destructive manner under normal pressure.

[0066] In one example, the water tank has a space in which a liquid can be accommodated. The type of the liquid accommodated in the water tank is not particularly limited. For example, water can be accommodated. Alternatively, a liquid such as ethanol can be used, or an electrically insulating liquid such as silicone oil can be used.

[0067] The battery cell fixture fixes the battery cell to prevent the battery cell from moving during the volume measurement. As described above, the battery cell fixture includes: a first plate and a second plate; a bolt and a nut that fix the first plate and the second plate in a state where the battery cell is interposed between the first plate and the second plate; and a spacer that is located between the first plate and the second plate to specify a separation distance, and the spacer has a structure surrounding the bolt. At this time, the spacer includes a slit unit that is open along the longitudinal direction.

[0068] In addition, the battery cell can be a pouch-type cell. Specifically, the pouch-type cell can have a structure in which an electrode assembly having a positive electrode / separator / negative electrode structure is embedded in an outer material while being connected to an electrode lead formed outside the outer material of the laminated sheet. The electrode leads can be led to the outside of the sheet and can extend in the same or opposite directions to each other.

[0069] In addition, a scale is used to measure the weight of the battery cell fixture in which the battery cell is accommodated, and to measure the weight of the battery cell fixture outside the water tank and the weight of the battery cell fixture in the liquid. Here, the weight outside the water tank refers to the weight of the battery cell fixture in the air. The scale can be a conventional scale for measuring weight. For example, the scale can be a spring scale or an electronic scale.

[0070] In one example, the battery cell volume measurement device further includes a charge and discharge unit that is electrically connected to the battery cell. The charge / discharge unit can supply power for charging to the secondary battery or receive discharge power from the secondary battery. Here, supplying power to the secondary battery is not limited to supplying power sufficient to fully charge the secondary battery. Supplying power to the secondary battery can also mean supplying power sufficient to measure the voltages of the first electrode lead and the second electrode lead to evaluate the performance of the secondary battery. This also applies to the meaning of receiving discharge power from the secondary battery, so its repeated description is omitted here.

[0071] In addition, the present invention provides a method for measuring the volume of a battery cell by using the above battery cell volume measurement device.

[0072] In one example, the method for measuring the volume of a battery cell according to the present invention is performed by placing the battery cell in the battery cell fixture and then measuring the weights before and after the volume change of the battery cell, respectively.

[0073] In a specific example, the method for measuring the volume of a battery cell according to the present invention includes: placing the battery cell between battery cell jigs, and then measuring the weight of the battery cell jig in air; placing the battery cell jig in a water tank that already contains a liquid, and then measuring the weight of the battery cell jig in the liquid; and calculating the volume of the battery cell after volume change by the following formula 1:

[0074]

Formula 1

[0075]

[0076] Here, V represents the volume of the battery cell after volume change, Wl represents the weight of the battery cell jig in air, W2 represents the weight of the battery cell jig contained in the liquid, and ρ represents the density of the liquid.

[0077] As described above, the method for measuring the volume of a battery cell according to the present invention uses Archimedes' principle. Specifically, the difference between the weight of the battery cell before the battery cell is immersed in the liquid contained in the water tank and the weight of the battery cell after the battery cell is immersed in the liquid can be the weight of the liquid whose volume increases as the battery cell is immersed in the liquid. At this time, since the weight of the liquid displaced as the battery cell is immersed in the liquid is the same as the buoyancy force, the volume of the battery cell can be identified based on the measured buoyancy force.

[0078] Similarly, according to the battery cell volume measurement method of the present invention, by only measuring the weight of the battery cell without the process of stamping the battery, the volume of the battery cell can be measured in a non-destructive manner under normal pressure.

[0079] In addition, the step of placing the battery cell between battery cell jigs and then measuring the weight of the battery cell jig in air is performed. At this time, a scale such as a spring scale can be used to measure the weight of the battery cell jig in which the battery cell is placed.

[0080] In addition, the battery cell jig is placed in a water tank that already contains a liquid. The type of the liquid contained in the water tank is not particularly limited. For example, water can be contained. Alternatively, a liquid such as ethanol can be used, or an electrically insulating liquid such as silicone oil can also be used.

[0081] In one example, the method for measuring the volume of a battery cell according to the present invention includes the step of measuring the weight of the battery cell jig in the liquid. In a specific example, the step of measuring the weight of the battery cell jig in the liquid includes the process of charging and discharging the battery cell. During the charging and discharging process, the battery cell can be activated by charging and discharging the battery cell by a charging and discharging unit electrically connected to the battery cell.

[0082] In addition, by measuring the weight of the battery cell accommodated in the liquid, it is possible to measure the volume of the internal gas generated during charging / discharging through the charging / discharging process.

[0083] Thereafter, in the method for measuring the volume of the battery cell according to the present invention, by using the weight of the battery cell measured in air and the weight of the battery cell measured in the liquid, the volume change amount of the battery cell can be calculated by Formula 1.

[0084] In another example, the method further includes heating the liquid to a predetermined temperature during the measurement of the weight of the battery cell jig accommodated in the liquid. This process can be performed by the temperature control unit of the battery cell volume measuring device. For example, it can be performed by heating the iron plate surrounding the water tank. Here, the process of heating the liquid should be performed before the step of measuring the weight of the battery cell accommodated in the liquid. The temperature of the liquid can be measured by a temperature measuring unit such as a thermocouple, and through this temperature measuring unit, the liquid can be heated to a predetermined temperature.

[0085] Therefore, the method for measuring the volume of the battery cell according to the present invention further includes the step of calculating the volume change of the battery cell according to the temperature of the liquid. For example, after setting the temperature of the liquid to 45 °C, 60 °C, or 80 °C and measuring the volume of the battery cell at this time respectively, the volume change trend of the battery cell according to the temperature can be obtained.

[0086] Hereinafter, the present invention will be described in more detail with reference to the drawings and the like. Since the inventive concept of the present invention allows various variations and numerous embodiments, specific embodiments will be shown in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific forms disclosed, and it should be understood to include all variations, equivalent forms, and alternative forms within the spirit and scope of the present invention.

[0087] (First Embodiment)

[0088] Figure 3 is a cross-sectional view of a battery cell jig including a spacer laminate according to an embodiment of the present invention.

[0089] Reference Figure 3, the battery cell fixture 100 according to the present invention includes: a first plate 120 and a second plate 130; a bolt 140 and a nut 150, which fix the first plate and the second plate in a state where the battery cell 110 is interposed between the first plate 120 and the second plate 130; and a spacer laminate 170, which is located between the first plate 120 and the second plate 130 at a specified separation distance, and the spacer laminate 170 is formed by laminating n spacers 160 having a structure surrounding the bolt 140, where n is an integer equal to or greater than 2. At this time, each spacer 160 includes a slit unit 161 that opens along the longitudinal direction of the spacer 160.

[0090] Specifically, the spacer laminate 170 is used to keep the distance between the first plate 120 and the second plate 130 constant and has a structure surrounding the bolt 140. At this time, the slit unit 161 of the spacer opens from one side to the other along the longitudinal direction of the spacer 160. More specifically, the slit unit 161 opens from one side to the other along the longitudinal direction of the spacer laminate 170. That is, since the spacer 160 or the spacer laminate 170 opens along the longitudinal direction, when measuring the volume of the battery cell 110 using Archimedes' principle, it is possible to prevent water from remaining in the spacer 160 or prevent gas from filling the spacer 160.

[0091] The slit unit 161 of the spacer 160 can open at an average of 60 degrees based on the axis. Since the slit unit 161 opens at the above angle, it is possible to prevent water from remaining in the space between the battery cell fixture 100 and the spacer 160 or prevent gas from filling the space. In addition, by using n spacers 160, the space between the first plate 120 and the second plate 130 can be adjusted, and when measuring the volume change of the battery cell 110 using Archimedes' principle, since the spacer 160 opens at the above angle, it is possible to measure the volume change of the battery cell 110 after separating the spacer 160 from the battery cell fixture 100.

[0092] At this time, the height of the spacer laminate 170 formed by laminating n spacers 160 corresponds to the height of the battery cell 110 interposed between the first plate 120 and the second plate 130. Therefore, it is possible to easily adjust the space between the first plate 120 and the second plate 130. More specifically, the user allows the battery cell 110 to be located on the second plate 130 connected to the bolt 140, and inserts n spacers 160 into the bolt 140. Thereafter, the first plate 120 is connected and fastened by the nut 150.

[0093] In addition, the battery cell fixture 100 according to the present invention includes a plurality of bolts 140 and nuts 150. Specifically, the battery cell fixture 100 according to the present invention includes 4 to 12 bolts 140 and nuts 150 respectively. For example, the battery cell fixture 100 includes 10 bolts 140 and nuts 150 respectively. However, the present invention is not limited thereto.

[0094] Figure 4 is a schematic view showing a spacer laminate in a battery cell fixture according to an embodiment of the present invention. Refer to Figure 4 , the spacer 160 according to the present invention has a hole, and the bolt 140 passes through the hole in the axial direction. In addition, the spacer 160 includes a slit unit 161 that is open in the longitudinal direction.

[0095] In addition, the n spacers 160 constituting the spacer laminate 170 may have the same height or may have different heights. For example, the n spacers 160 may be spacers 160 having different heights. Since the n spacers 160 constituting the spacer laminate 170 have different heights, it can be made easier to allow the height of the spacer laminate 170 to correspond to the height of the battery cell 110.

[0096] In the battery cell fixture 100 according to the present invention, by including the spacer 160 having the slit unit 161, when measuring the volume change of the battery cell 110 using Archimedes' principle, it is possible to prevent water from staying in the space between the battery cell fixture 100 and the spacer 160. In addition, by forming the spacer laminate 170 formed by laminating the spacers 160 to have a height corresponding to the height of the target battery cell 110, it is possible to easily adjust the space between the first plate 120 and the second plate 130 with the battery cell 110 interposed therebetween.

[0097] (Second Embodiment)

[0098] Figure 5 is a cross-sectional view of a battery cell fixture including a spacer laminate according to another embodiment of the present invention.

[0099] Refer to Figure 5, the battery cell fixture 200 according to the present invention includes: a first plate 220 and a second plate 230; a bolt 240 and a nut 250, which fix the first plate and the second plate in a state where the battery cell 210 is interposed between the first plate 220 and the second plate 230; and a spacer laminate 270, which is located between the first plate 220 and the second plate 230 at a specified separation distance, and the spacer laminate 270 is formed by laminating n spacers 260 having a structure surrounding the bolt 240, where n is an integer equal to or greater than 2. At this time, each spacer 260 includes a slit unit 261 that opens along the longitudinal direction of the spacer 260.

[0100] Specifically, the spacer laminate 270 is used to keep the distance between the first plate 220 and the second plate 230 constant and has a structure surrounding the bolt 240. More specifically, the spacer laminate 270 has a structure formed by laminating n spacers 260 (n is an integer equal to or greater than 2).

[0101] Figure 6 is a schematic diagram of a spacer in a battery cell fixture showing another embodiment of the present invention, and Figure 7 is a schematic diagram of a spacer laminate in a battery cell fixture according to another embodiment of the present invention.

[0102] Reference Figure 6 and Figure 7 , one end of the spacer 260 has a protrusion or a recess, the protrusion or the recess has a central region that has protruded or recessed into a stepped structure, and the other end of the spacer 260 has a protrusion or a recess, the protrusion or the recess has a central region that has protruded or recessed into a stepped structure. In addition, the spacer 260 includes a slit unit 261 that opens along the longitudinal direction.

[0103] Specifically, one end of the spacer 260 has a protrusion 262, the protrusion 262 has a central region that has protruded into a stepped structure, and the other end of the spacer 260 may have a recess 263, the recess 263 has a central region that has recessed into a stepped structure. In a specific example, in the spacer laminate 270, one end of the k-th spacer 260 has a protrusion 262, and the other end of the (k + 1)-th spacer 260 has a recess 263 corresponding to the protrusion 262 of the k-th spacer. Here, k is an integer equal to or greater than 1 and equal to or less than n - 1. That is, the recess of the (k + 1)-th spacer 260 can be laminated on the protrusion of the k-th spacer 260.

[0104] In addition, since each component has been described above, a detailed description of each component will be omitted here.

[0105] (Third Embodiment)

[0106] Figure 8 FIG. 2 is a cross-sectional view of a battery cell fixture including a spacer laminate according to another embodiment of the present invention.

[0107] Referring to Figure 8 FIG. 3, a battery cell fixture 300 according to the present invention includes: a first plate 320 and a second plate 330; a bolt 340 and a nut 350 that fix the first plate and the second plate in a state where a battery cell 310 is interposed between the first plate 320 and the second plate 330; and a spacer laminate 370 that is located between the first plate 320 and the second plate 330 to specify a separation distance, and the spacer laminate 370 is formed by laminating n spacers 360 having a structure surrounding the bolt 340, where n is an integer equal to or greater than 2. At this time, each spacer 360 includes a slit unit 361 that is open along the longitudinal direction of the spacer 360.

[0108] Specifically, the spacer laminate 370 is configured to keep the distance between the first plate 320 and the second plate 330 constant and has a structure surrounding the bolt 340. More specifically, the spacer laminate 370 has a structure formed by laminating n spacers 360 (n is an integer equal to or greater than 2).

[0109] Figure 9 FIG. 4 is a schematic view showing a spacer in a battery cell fixture according to another embodiment of the present invention, and Figure 10 FIG. 5 is a schematic view showing a spacer laminate in a battery cell fixture according to another embodiment of the present invention.

[0110] Referring to Figure 9 and Figure 10 FIG. 6, one end of the spacer 360 has a protrusion or a groove, and the other end of the spacer 360 has a groove or a protrusion. Specifically, in the spacer laminate 370, one end of the k-th spacer 360 has a protrusion 362, and the other end of the (k + 1)-th spacer 360 has a groove 363 corresponding to the protrusion 362 of the k-th spacer. Here, k is an integer equal to or greater than 1 and equal to or less than n - 1. That is, by allowing the groove of the (k + 1)-th spacer 360 to contact the protrusion of the k-th spacer 360, the n spacers 360 can be easily laminated.

[0111] In addition, when the (k + 1)-th spacer 360 is stacked on the upper part of the k-th spacer 360, rotation of the spacer 360 in the axial direction can be prevented by the bumps and grooves, and the space between the first plate 320 and the second plate 330 with the battery cell 310 interposed therebetween can be easily adjusted.

[0112] (Fourth Embodiment)

[0113] Figure 11 is a view showing each component of a battery cell volume measuring device according to yet another embodiment of the present invention.

[0114] Reference Figure 11 , the battery cell volume measuring device according to the present invention includes: a battery cell jig 400; a water tank 480 in which a liquid is accommodated; and a scale 385 that measures the weight of the battery cell jig 400 accommodating the battery cell 410 on the outside and inside of the water tank 480, respectively. The battery cell volume measuring device according to the present invention uses Archimedes' principle to measure the volume change amount of the battery cell 410. More specifically, the volume change amount of the battery cell 410 can be calculated by calculating the difference between the weight of the battery cell 410 measured before the battery cell 410 is immersed in the liquid accommodated in the water tank 480 and the weight of the battery cell 410 after the battery cell 410 is immersed in the liquid.

[0115] The water tank 480 has a space capable of accommodating a liquid therein. The type of the liquid accommodated in the water tank 480 is not particularly limited. For example, water can be accommodated. Alternatively, a liquid such as ethanol can be used, or an electrically insulating liquid such as silicone oil can be used.

[0116] The battery cell jig 400 fixes the battery cell 410 to prevent the battery cell 410 from moving during volume measurement. As described above, the battery cell jig 400 includes: a first plate 420 and a second plate 430; a bolt 440 and a nut 450 that fix the first plate and the second plate in a state where the battery cell 410 is interposed between the first plate 420 and the second plate 430; and a spacer (not shown) that is located between the first plate and the second plate to specify a separation distance and has a structure surrounding the bolt 440. At this time, the spacer includes a slit unit (not shown) that is open along the longitudinal direction.

[0117] In addition, a scale 485 is used to measure the weight of the battery cell fixture 400 in which the battery cell 410 is accommodated, and to measure the weight outside the water tank 480 and the weight in the liquid. Here, the weight outside the water tank 480 refers to the weight of the battery cell fixture 400 in the air. The scale 485 can be a conventional scale for measuring weight. For example, the scale 485 can be a spring scale or an electronic scale. In the drawings, a spring scale is shown as the scale 485, but the present invention is not limited to this example.

[0118] In addition, the battery cell volume measuring device further includes a charge and discharge unit 490, which is electrically connected to the battery cell. The charge and discharge unit 490 can activate the battery cell through charging / discharging by being electrically connected to the electrode assembly of the battery cell 410. At this time, the charge and discharge unit 490 can be electrically connected to the electrode leads of the battery cell 410 through a charging / discharging wire (not shown).

[0119] In addition, the volume of the internal gas generated during charging / discharging can be measured by measuring the weight of the battery cell 410 accommodated in the liquid.

[0120] In addition, the present invention provides a method for measuring the volume of a battery cell by using the above battery cell volume measuring device. In a specific example, the method for measuring the volume of a battery cell according to the present invention is performed by placing the battery cell in the battery cell fixture and then measuring the weight before and after the volume change of the battery cell, respectively.

[0121] As described above, the method for measuring the volume of a battery cell according to the present invention uses Archimedes' principle. Hereinafter, this method will be described in detail.

[0122] Figure 12 is a flowchart showing a method for measuring the volume of a battery cell according to still another embodiment of the present invention.

[0123] Reference Figure 12 , the method for measuring the volume of a battery cell according to the present invention includes: placing the battery cell in the battery cell fixture and then measuring the weight of the battery cell fixture in the air (S10); placing the battery cell fixture in a water tank that already contains liquid and then measuring the weight of the battery cell fixture in the liquid (S20); and calculating the volume after the volume change of the battery cell by the following formula 1 (S30):

[0124]

Formula 1

[0125] V = (W1 - W2) / ρ

[0126] Here, V represents the volume after the volume change of the battery cell, Wl represents the weight of the battery cell fixture in air, W2 represents the weight of the battery cell fixture contained in the liquid, and ρ represents the density of the liquid.

[0127] As described above, the method for measuring the volume of a battery cell according to the present invention uses Archimedes' principle. Specifically, the difference between the weight of the battery cell before it is immersed in the liquid contained in the water tank and the weight of the battery cell after it is immersed in the liquid can be the weight of the liquid whose volume increases as the battery cell is immersed in the liquid. At this time, since the weight of the liquid displaced as the battery cell is immersed in the liquid is the same as the buoyancy force, the volume of the battery cell can be identified based on the measured buoyancy force.

[0128] Similarly, according to the battery cell volume measurement method of the present invention, by only measuring the weight of the battery cell without the process of stamping the battery, the volume of the battery cell can be measured in a non-destructive manner under normal pressure.

[0129] Specifically, measure the weight Wl of the battery cell fixture in which the battery cell is located in air, and after performing the charge / discharge process with the battery cell immersed in ethanol, measure the weight W2 of the battery cell fixture contained in the liquid.

[0130] At this time, the weight W1 of the battery cell fixture in air is 110 g, and the weight W2 of the battery cell fixture contained in the liquid is 100 g. If the density of ethanol is ρ = 0.789 g / cm 3 and the volume change amount of the battery cell is V, then the weight change amount of the battery cell is the same as the weight of the ethanol displaced, and the volume of the ethanol displaced is the same as the volume change amount of the battery cell due to gas generation, that is, V. Therefore, in summary, ρ is (the weight of the ethanol displaced) / (the volume of the ethanol displaced). At this time, since the volume of the ethanol that has been displaced is (the weight of the ethanol that has been displaced) / ρ, V can be calculated by (110 - 100) / 0.789. That is, the volume change amount of the battery cell is approximately 12.674 cm 3 .

[0131] In the above, the present invention has been described in more detail through the drawings and examples. Therefore, the embodiments described in the specification and the configurations described in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. It should be understood that various equivalent forms and variations can exist to replace them when submitting this application.

[0132]

Description of Reference Numerals

[0133] 10, 100, 200, 300, 400: Battery cell fixture

[0134] 11, 110, 210, 310, 410: Battery cell

[0135] 12, 120, 220, 320, 420: First plate

[0136] 13, 130, 230, 330, 430: Second plate

[0137] 14, 140, 240, 340, 440: Bolt

[0138] 15, 150, 250, 350, 450: Nut

[0139] 16, 160, 260, 360: Spacer

[0140] 161, 261, 361: Slit unit

[0141] 262: Protrusion

[0142] 263: Depression

[0143] 362: Bump

[0144] 363: Groove

[0145] 170, 270, 370: Spacer laminate

[0146] 480: Water tank

[0147] 485: Scale

[0148] 490: Charge and discharge unit

Claims

1. A battery cell fixture, comprising: A first plate and a second plate; A bolt and a nut, in a state where the battery cell is between the first plate and the second plate, the bolt and the nut fix the first plate and the second plate; And A spacer laminate, the spacer laminate is located between the first plate and the second plate at a specified separation distance, and the spacer laminate is generated by laminating n spacers having a structure surrounding the bolt, where n is an integer equal to or greater than 2, and Wherein, each of the spacers includes a slit unit, the slit unit is formed in the side wall of the spacer and opens along the longitudinal direction of the spacer.

2. The battery cell fixture according to claim 1, wherein, The slit unit of the spacer opens from one side to the other side along the longitudinal direction of the spacer laminate.

3. The battery cell fixture according to claim 1, wherein, The slit unit of the spacer opens within a range of 10 degrees to 70 degrees with respect to the axis center.

4. The battery cell fixture according to claim 1, wherein, One end of the spacer has a protrusion or a recess, the protrusion or the recess has a central region that has protruded or recessed into a stepped structure, and Wherein, the other end of the spacer has a protrusion or a recess, the protrusion or the recess has a central region that has protruded or recessed into a stepped structure.

5. The battery cell fixture according to claim 1, wherein, One end of the k-th spacer has a protrusion or a recess, and the other end of the (k + 1)-th spacer has a recess or a protrusion corresponding to the protrusion or the recess of the k-th spacer, and Wherein, k is an integer equal to or greater than 1 and equal to or less than n - 1.

6. The battery cell fixture according to claim 1, wherein, One end of the spacer has a bump or a groove, and Wherein, the other end of the spacer has a groove or a bump.

7. The battery cell fixture according to claim 1, wherein, One end of the k-th spacer has a bump or a groove, and the other end of the (k + 1)-th spacer has a groove or a bump corresponding to the bump or the groove of the k-th spacer, and Wherein, k is an integer equal to or greater than 1 and equal to or less than n - 1.

8. The battery cell fixture according to claim 1, wherein, The battery cell fixture includes 4 to 12 bolts and nuts respectively, and Wherein, the spacer is fastened by at least one bolt.

9. A device for measuring the volume of a battery cell, the device comprising: The battery cell fixture according to claim 1; A water tank, in which a liquid is contained; And A scale, the scale measures the weights of the battery cell fixture containing the battery cell outside and inside the water tank respectively.

10. The device according to claim 9, further comprising a charge and discharge unit, the charge and discharge unit is electrically connected to the battery cell.

11. A method for measuring the volume of a battery cell, the method measures the volume of the battery cell by placing the battery cell in the battery cell fixture according to claim 1 and then measuring the weights before and after the volume change of the battery cell respectively.

12. The method according to claim 11, comprising: Placing the battery cell in the battery cell fixture, and then measuring the weight of the battery cell fixture in the air; Place the battery cell fixture in a water tank that already contains liquid, and then measure the weight of the battery cell fixture in the liquid; and Calculate the volume after the volume change of the battery cell using the following Formula 1: 【Formula 1】 Where, V represents the volume after the volume change of the battery cell, W1 represents the weight of the battery cell fixture in air, W2 represents the weight of the battery cell fixture contained in the liquid, and ρ represents the density of the liquid.

13. The method according to claim 12 further comprises: Charge and discharge the battery cell while measuring the weight of the battery cell fixture contained in the liquid.

14. The method according to claim 12, further comprising: Heat the liquid to a predetermined temperature while measuring the weight of the battery cell fixture contained in the liquid.

15. The method according to claim 14, wherein, Calculating the volume after the volume change of the battery cell includes: calculating the volume change of the battery cell according to the temperature of the liquid.

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