Apparatus for measuring flow flow of exhaust gas in secondary battery cell device and measurement method using same

Abstract

An apparatus for measuring a flow rate of exhaust gas of a secondary battery cell device according to an embodiment of the present invention includes a chamber for accommodating the secondary battery cell device and a duct-shaped flow rate measurement unit connected to an outlet of the chamber.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2022-0144750 filed in the Korean Intellectual Property Office on November 2, 2022, the entire contents of which are incorporated herein by reference.

[0003] The present disclosure relates to a safety measurement device of a secondary battery cell, and more particularly, to a device and method for measuring safety with respect to a single secondary battery cell by measuring a flow rate of a gas generated when ignited. Background Art

[0004] In modern society, as the use of portable devices such as mobile phones, laptop computers, camcorders, digital cameras, etc. has become widespread, the development of technology in the field related to the above-mentioned mobile devices has become more active. In addition, rechargeable secondary battery cells are used as a power source for electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (P-HEV), etc. to solve air pollution such as existing gasoline vehicles using fossil fuels, and therefore, the demand for the development of secondary battery cells is increasing.

[0005] Currently commercial secondary battery cells include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, lithium secondary battery cells, etc. Among them, lithium secondary battery cells rarely have a memory effect compared to nickel-based secondary battery cells, and therefore, lithium secondary battery cells have attracted much attention due to the advantages of free charge and discharge, very low self-discharge rate, and high energy density.

[0006] These lithium secondary battery cells mainly use lithium-based oxides and carbon materials as positive electrode active materials and negative electrode active materials, respectively. A lithium secondary battery cell includes: an electrode assembly in which a positive electrode plate and a negative electrode plate coated with a positive electrode active material and a negative electrode active material, respectively, are placed with a separator interposed therebetween; and a battery case that seals and contains the electrode assembly together with an electrolyte.

[0007] Generally, lithium secondary battery cells may be divided into can type secondary battery cells in which an electrode assembly is built in a metal can and pouch type secondary battery cells in which an electrode assembly is built in a pouch of an aluminum laminate sheet, according to the shape of an exterior material.

[0008] In the case of secondary battery cells used in small devices, 2 or 3 battery cells are placed, but in the case of secondary battery cells used in medium and large devices (such as automobiles), battery modules in which multiple battery cells are electrically connected are used. These battery modules have improved capacity and output by connecting multiple battery cells in series or in parallel and forming a battery cell assembly. One or more battery modules may be installed with various control and protection systems, such as a battery disconnect unit (BDU), a battery management system (BMS), a cooling system, etc., to form a battery pack.

[0009] In particular, recently, due to the development of high-capacity battery cells, the safety of secondary battery cells, especially the heat propagation characteristics, has been considered important. These safety characteristics can be achieved by simulating the overcharge or overheating state of the secondary battery cells and analyzing the gases generated during the fire. At this time, when analyzing a large number of secondary battery cells at a time, there is a problem that it is difficult to compare the characteristics of the secondary battery cells and difficult to accurately analyze. Therefore, it is necessary to develop a device and method that can accurately analyze the gases generated during overcharge and overheating with respect to a single secondary battery cell (single battery cell). Summary of the invention

[0010] [Technical issues]

[0011] The present disclosure seeks to provide an apparatus and method capable of accurately analyzing gas generated during overcharge and overheating in order to evaluate heat propagation characteristics of a single secondary battery cell with a simple structure.

[0012] However, the problems to be solved by the embodiments of the present disclosure are not limited to the above-mentioned problems and can be expanded in various ways within the scope of the technical concept included in the present disclosure.

[0013] [Technical solution]

[0014] An apparatus for measuring a flow rate of a gas in a secondary battery cell according to an embodiment of the present disclosure may include a chamber accommodating the secondary battery cell and a flow rate measuring unit connected to an outlet of the chamber and having a pipe shape.

[0015] The length of the flow measurement unit may be 800 mm to 2000 mm.

[0016] The diameter of the flow measurement cell can be between 2.5 cm and 13 cm.

[0017] The volume of the remaining space in the chamber after accommodating the secondary battery cell may be 0.1L to 5L.

[0018] The chamber may have a rectangular hexahedral box shape.

[0019] The chamber and ducting can be made of aluminum or stainless steel.

[0020] A method for measuring the flow rate of gas in a secondary battery cell according to another embodiment of the present disclosure may include: accommodating the secondary battery cell in a chamber; causing fire in the secondary battery cell by increasing the temperature inside the chamber; and measuring the temperature of the gas generated from the secondary battery cell by the fire, wherein the gas is discharged to a flow measurement unit that is connected to an outlet of the chamber and has a shape of a pipe.

[0021] The gas exhausted from the flow measurement unit may include only the gas generated from the secondary battery cells without mixing a separate carrier gas.

[0022] More than 95% of the gas generated from the secondary battery cells may be exhausted to the flow measurement unit.

[0023] One to four secondary battery cells may be accommodated in the chamber.

[0024] [Beneficial Effects]

[0025] According to the embodiments of the present disclosure, it is possible to provide an apparatus and method capable of accurately analyzing gas generated during overcharge and overheating in order to evaluate heat propagation characteristics of a single secondary battery cell with a simple structure.

[0026] The effects of the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a diagram illustrating an apparatus for measuring a flow rate of a gas in a secondary battery cell according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0028] The present disclosure will be described more fully below with reference to the accompanying drawings so that those skilled in the art can easily implement the embodiments of the present disclosure. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein.

[0029] In order to clearly describe the present disclosure, parts irrelevant to the description are omitted, and the same reference numerals are used throughout the specification to refer to the same or similar components.

[0030] In addition, since the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, the present disclosure is not necessarily limited to those shown. In the drawings, the thickness is enlarged to clearly show the various layers and regions. In addition, in the drawings, the thickness of some layers and regions is exaggerated for the convenience of explanation.

[0031] In addition, it should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements. In addition, "above" or "on" a reference portion means above or below the reference portion, and does not necessarily mean "above" or "on" in an opposite direction of gravity.

[0032] Furthermore, throughout the specification, when a part “includes” a certain component, it means that unless otherwise specified, the part may also include other components without excluding the other components.

[0033] Furthermore, throughout the specification, when it is referred to as “on a plane”, it means when the target portion is viewed from above, and when it is referred to as “on a cross section”, it means when a cross section of the target portion cut vertically is viewed from the side.

[0034] In the following, reference is made to Figure 1 An apparatus for analyzing gases in secondary battery cells is described.

[0035] Figure 1 is a diagram illustrating an apparatus for measuring a flow rate of a gas in a secondary battery cell according to an embodiment of the present disclosure.

[0036] The apparatus 100 for analyzing gas in the secondary battery cell 200 is configured to analyze gas exhausted from the secondary battery cell 200 .

[0037] The device 100 for analyzing gas in the secondary battery cell 200 includes a chamber 110 accommodating the secondary battery cell 200 and a flow measurement unit 120 having a pipe shape to serve as a passage for gas exhausted from the secondary battery cell 200. In addition, although not shown, the device 100 may further include an overload device (not shown) installed inside or outside the chamber 110 to increase the internal temperature and a flow meter (not shown) installed inside or outside the flow measurement unit 120 to measure the flow rate.

[0038] The chamber 110 is configured to accommodate the secondary battery cell 200 as an analysis object. For example, the chamber 110 may have a rectangular hexahedral box shape having a space inside, such as Figure 1 The chamber 110 may be made of aluminum or stainless steel to withstand heat and the like.

[0039] The size of the space inside the chamber 110 may be set so as to accommodate only a single secondary battery cell 200. At this time, the size of the internal space is set so that the volume of the remaining portion after accommodating the single secondary battery cell 200 is 0.1 L to 5 L. When the volume exceeds 5 L and is too large compared to the size of the secondary battery cell 200, while the generated high-temperature gas passes through the space, a portion of the high-temperature gas may be phase-changed into a liquid, and therefore, the amount of gas measured by the flow measurement unit 120 may be less than the flow rate of the high-temperature gas actually generated. Therefore, it is difficult to perform accurate measurement, and therefore, it is necessary to limit the remaining volume after accommodating the secondary battery cell 200 to the above range.

[0040] In addition, only a single secondary battery cell 200 is accommodated inside the chamber 110, and its characteristics can be evaluated. Conventionally, the heat propagation characteristics are simulated and measured in a stacked or module state, in which a plurality of secondary battery cells 200 are stacked, but in this case, the scale of the fire increases and the amount of gas generated also increases, which leads to the problem that it is difficult to ensure safety in the experimental stage. For this reason, in the present embodiment, one to four secondary battery cells 200 are accommodated in the chamber 110, and the flow rate of their gas is measured when a fire occurs.

[0041] An outlet 111 through which high temperature gas generated from the secondary battery cell 200 is discharged is formed on one side of the chamber 110, and a flow measurement unit 120 having a pipe shape is connected to the outlet 111. The flow measurement unit 120 is formed in the shape of a pipe so that the high temperature gas generated from the secondary battery cell 200 can pass therethrough.

[0042] A flow meter capable of measuring the flow rate of the gas passing through the flow measurement unit 120 may be provided inside or outside the flow measurement unit 120. The flow measurement unit 120 may also be made of a material that can withstand heat and pressure, such as aluminum or stainless steel. The flow measurement unit 120 may be located at the center of one side of the box-shaped chamber 110 and may be formed in only one direction or in two directions, such as Figure 1 However, at this time, the flow measurement unit 120 is configured only to exhaust the gas, and in the present embodiment, the flow rate is measured without introducing a separate carrier gas or the like to measure the flow rate.

[0043] The length L of the flow measurement unit 120 may be 800 mm to 2000 mm, and the diameter D may be 2.5 cm to 13 cm. Within this range, the length L and the diameter D of the flow measurement unit 120 may be appropriately changed according to the size of the chamber 110. That is, as the chamber 110 becomes smaller, the length L and the diameter D may become smaller. In addition, when the length L of the flow measurement unit 120 is set to 800 mm to 2000 mm and the diameter D thereof is set to 2.5 cm to 13 cm, since the gas generated from the secondary battery cell 200 maintains the initial generation temperature and passes through the flow measurement unit 120, the flow of the generated gas may be accurately measured. That is, when the length L of the flow measurement unit 120 increases and the diameter D thereof decreases, there is a problem that during the process of passing through the flow measurement unit 120, the flow is lost, and the flow is measured to be less than the actual flow. Therefore, for accurate flow measurement, the length L and the diameter D of the flow measurement unit 120 may be controlled within the above range.

[0044] According to the apparatus for measuring the flow rate of gas of the present embodiment as described above, the flow rate of exhaust gas can be accurately measured with respect to a single secondary battery cell 200 without losing the flow rate of generated gas.

[0045] Next, we will refer to Figure 1 A method of measuring a flow rate of a gas in the secondary battery cell 200 according to another embodiment of the present disclosure is described.

[0046] First, a single secondary battery cell 200 is located inside the chamber 110. At this time, only the flow of a single secondary battery cell 200 is measured instead of several secondary battery cells, and thus safety is improved and each battery cell can be evaluated. In addition, compared with the case where a simulation experiment is performed on a plurality of secondary battery cells 200 at a time, the time and energy required for heating for ignition can be reduced.

[0047] Next, the internal temperature is increased by an overload device (not shown) installed inside or outside the chamber 110. In the present embodiment, heating by the overload device is described as an example, but the present embodiment is not limited thereto, and overload may be induced in the secondary battery cell 200 by causing an overcharge state. When overload is induced in the secondary battery cell 200 by heating or the like, the secondary battery cell 200 emits high-temperature gas.

[0048] When high temperature gas is emitted, all high temperature gas passes through the flow measurement unit 120 via the outlet 111. The high temperature gas passing through the flow measurement unit 120 is flow-measured and temperature-measured using a flow meter. At this time, the flow rate is measured by measuring the flow rate of the high temperature gas emitted from the secondary battery cell 200 by allowing all the generated gas to pass through the flow measurement unit 120 without introducing a separate reference gas (carrier gas), and therefore, the flow rate can be accurately measured in a simple manner without losing the generated gas. In other words, when introducing a carrier gas, etc., not only is the process complicated, but also in the process of mixing the carrier gas with other gases, the actual measured flow rate may be reduced by liquefying a part of the high temperature gas. In addition, as described above, in the present embodiment, the volume of the remaining space other than the secondary battery cell 200 inside the chamber 110 is limited to 0.1 L to 5 L, and the length L and diameter D of the flow measurement unit 120 are limited to 800 mm to 2000 mm and 2.5 cm to 13 cm, respectively, thereby also preventing the high temperature gas from liquefying in the remaining space or liquefying while passing through the flow measurement unit 120.

[0049] Next, the characteristics of the generated gas are analyzed with reference to the flow rate or temperature measured by the flow rate measurement unit 120. For example, based on the degree of the specified flow rate, it can be predicted whether the heat transfer characteristics are improved.

[0050] As described above, according to the method of measuring the flow rate of gas in the secondary battery cell 200 of the present embodiment, the flow rate of the generated high temperature gas can be accurately measured without loss through a simple structure and method.

[0051] Although the embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements made by a person of ordinary skill in the art to which the present disclosure belongs also belong to the scope of the present disclosure.

[0052] [Explanation of Reference Numerals]

[0053] 100: Device for measuring the flow rate of gas

[0054] 200: Secondary battery cells

[0055] 110: Chamber

[0056] 111: Exit

[0057] 120: Flow measurement unit

Claims

1. A device for measuring the flow rate of gas in a secondary battery cell, the device comprising: a chamber, the chamber accommodating the secondary battery cell; as well as A flow measurement unit is connected to the outlet of the chamber and has a shape of a pipe.

2. The device according to claim 1, wherein: The flow measurement unit has a length of 800 mm to 2000 mm.

3. The device according to claim 1, wherein: The flow measurement unit has a diameter of 2.5 cm to 13 cm.

4. The device according to claim 3, wherein: A volume of a remaining space in the chamber after accommodating the secondary battery cell is 0.1L to 5L.

5. The device according to claim 1, wherein: The chamber has a rectangular hexahedral box shape.

6. The device according to claim 1, wherein: The chamber and the conduit are made of aluminum or stainless steel.

7. A method for measuring the flow rate of gas in a secondary battery cell, the method comprising: accommodating the secondary battery cell in a chamber; causing fire in the secondary battery cell by increasing the temperature inside the chamber; as well as measuring a temperature of a gas generated from the secondary battery cell by ignition, The gas is discharged to a flow measurement unit which is connected to an outlet of the chamber and has a pipe shape.

8. The method according to claim 7, wherein: The gas exhausted from the flow measurement unit includes only the gas generated from the secondary battery cells without mixing a separate carrier gas.

9. The method according to claim 7, wherein: More than 95% of the gas generated from the secondary battery cells is discharged to the flow measurement unit.

10. The method according to claim 7, wherein: One to four secondary battery cells are accommodated in the chamber.

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