metal valve

Abstract

The casing of the energy storage module is required to expel internal gases, so the casing and a metal valve for gas exhaust are welded together to ensure airtightness by drawing in and expelling gases from inside the casing. However, the O-ring attached to the metal valve for gas exhaust may deform due to the heat generated when welding the casing, which can compromise the airtightness inside the casing. [Solution] The metal valve comprises a welded portion, a body portion, and a threaded portion, and at least one of the body portion and the threaded portion has a heat dissipation structure for heat from the welded portion. This suppresses deformation of the O-ring attached to the gas discharge metal valve due to the heat generated when welding the outer casing of the energy storage module.

Description

[Technical Field]

[0001] This disclosure relates to metal valves. [Background technology]

[0002] The outer casing (laminated film) of an energy storage module requires the removal of internal gases (so-called vacuum evacuation). For example, the outer casing and a metal valve for gas discharge are welded together to ensure airtightness by sucking out and discharging the gas from inside the casing. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2024-42569 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, the O-ring attached to the metal valve for gas discharge may deform due to the heat generated when the outer casing is welded, which can compromise the airtight seal inside the outer casing.

[0005] This disclosure has been made in view of the above, and aims to suppress the deformation of an O-ring attached to a metal valve for gas discharge caused by the heat generated when welding the outer casing of the energy storage module. [Means for solving the problem]

[0006] The metal valve according to this disclosure comprises a welded portion, a body portion, and a threaded portion, wherein at least one of the body portion and the threaded portion has a heat dissipation structure for heat from the welded portion. [Effects of the Invention]

[0007] According to this disclosure, deformation of the O-ring attached to the gas exhaust metal valve due to the heat generated when welding the outer casing of the energy storage module can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows an example of a metal valve according to an embodiment. [Figure 2] Figure 2 is a diagram illustrating an example of welding between a metal valve and an outer casing according to an embodiment. [Figure 3] Figure 3 shows an example of a heat dissipation structure for the body according to the embodiment. [Figure 4] Figure 4 shows an example of a heat dissipation structure for a screw portion according to the embodiment. [Figure 5] Figure 5 shows another example of the heat dissipation structure according to the embodiment. [Modes for carrying out the invention]

[0009] A metal valve according to the embodiments of this disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily substituted or substantially identical to those that are easily substituted by those skilled in the art.

[0010] First, a metal valve according to the embodiment will be described. The metal valve according to the embodiment is, for example, a metal valve for gas discharge for vacuuming the outer casing of an energy storage module mounted on a vehicle, and is connected by welding to the outer casing. The outer casing may be, for example, an aluminum laminate film used for the laminate pack (pouch) of the energy storage module. The energy storage module may be, for example, a bipolar lithium-ion battery sealed by an outer casing such as a laminate film. The vehicle on which the energy storage module is mounted may be, for example, an electric vehicle (BEV: Battery Electric Vehicle), a hybrid vehicle (HEV: Hybrid Electric Vehicle), a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle), etc.

[0011] Figure 1 shows an example of a metal valve according to an embodiment. The metal valve 1 shown in Figure 1 comprises, for example, a welded portion 2, a body portion 3, a threaded portion 4, and a threaded portion 5. The welded portion 2 is, for example, the part to which the outer casing of the energy storage module is welded, and as shown in Figure 1, it is plate-shaped.

[0012] The body portion 3 is, for example, cylindrical and hollow inside. This hollow may be, for example, a gas passage for discharging gas from inside the outer casing. The threaded portion 4 may be, for example, a hexagonal nut, with the central opening of the hexagon screwed into the threaded portion 5. The threaded portion 5 may be, for example, cylindrical and have threads on its surface. That is, the threaded portion 4 and the threaded portion 5 may be, for example, a female thread and a male thread. The threaded portion 5 is also, for example, hollow inside. The body portion 3 and the threaded portion 5 may be a single unit, and the hollows inside each may be connected to discharge gas from inside the outer casing. Furthermore, for example, a device for sucking gas from inside the outer casing and creating a vacuum may be connected to the threaded portion 5, and by tightening the threaded portion 4, airtightness of the outer casing and the inside of the metal valve 1 is ensured.

[0013] Next, welding between the metal valve 1 and the exterior body will be described. FIG. 2 is a diagram for explaining an example of welding between the metal valve and the exterior body according to the embodiment. FIG. 2 shows, for example, an example of a state where the exterior body 11 of the power storage module 10 is welded to the metal valve 1. As shown in FIG. 2, for example, in a state where the welding portion 2 is sandwiched between the exterior bodies 11, by sandwiching and heating with a hot plate 20, the resin on the surface of the exterior bodies 11 melts and is welded to the welding portion 2.

[0014] However, for example, depending on the size of the exterior body 11 or the like, heat may escape to the exterior body 11 side, and it may take 3 to 4 minutes for welding to the welding portion 2. In this case, for example, the temperature on the metal valve 1 side further rises due to heat conduction from the welding portion 2, and the O-ring 6 attached to the metal valve 1 may be deformed.

[0015] Here, the O-ring 6 shown in FIG. 2 is, for example, a seal ring made of rubber or plastic, and has a function of preventing gas leakage when the gas inside the exterior body 11 is sucked for vacuum evacuation. However, for example, when the O-ring 6 is deformed by heat, its gas leakage prevention function is impaired, and the airtightness inside the exterior body 11 cannot be ensured.

[0016] Therefore, for example, before welding the exterior body 11 and the welding portion 2, additional work such as temporarily removing the O-ring 6 from the metal valve 1 and reattaching it after welding is performed to prevent the O-ring 6 from being deformed.

[0017] Accordingly, one of the objects of the present disclosure is, for example, to suppress deformation of the O-ring 6 even when the O-ring 6 remains attached to the metal valve 1 when welding the exterior body 11 and the welding portion 2.

[0018] For example, as shown in Figure 2, the O-ring 6 is attached near the threaded portion 4 of the threaded portion 5, and the body portion 3 and threaded portion 4 are located between the welded portion 2 and the O-ring 6. Therefore, heat from the welded portion 2 is transferred to the O-ring 6 via the body portion 3 and threaded portion 4. To address this, the body portion 3 and threaded portion 4 are processed to provide a heat dissipation structure for the heat from the welded portion 2, thereby suppressing heat conduction to the O-ring 6 and, consequently, deformation. That is, for example, at least one of the body portion 3 and threaded portion 4 has a heat dissipation structure for the heat from the welded portion 2. This heat dissipation structure may be, for example, at least one of a fin shape and holes.

[0019] Figure 3 shows an example of a heat dissipation structure for the body according to the embodiment. Figure 3 shows an example in which the surface of the body 3 is micro-machined to create a heat dissipation structure with millimeter-sized bumps and grooves, i.e., fin shapes. This fin shape increases the surface area of ​​the body 3, thereby improving heat dissipation. Specific examples of the depth of the fin grooves will be described later.

[0020] Figure 4 shows an example of a heat dissipation structure for a screw portion according to the embodiment. As shown in Figure 4, the heat dissipation performance can be improved by creating irregularities on the surface of the screw portion 4 through micro-machining. The irregularities applied to the surface of the body portion 3 and the screw portion 4 may be, for example, millimeter-sized, or they may be at a level that can be confirmed by magnification with a microscope. Furthermore, the heat dissipation structure may be applied to either the body portion 3 or the screw portion 4, or both, and if both are applied, different heat dissipation structures may be applied to each.

[0021] Figure 5 shows another example of the heat dissipation structure according to the embodiment. As shown in Figure 5, the heat dissipation structure applied to the body portion 3 and the threaded portion 4 may be holes. Similar to the fin shape, these holes increase the surface area of ​​the body portion 3 and the threaded portion 4, thereby improving heat dissipation. These holes may be, for example, holes with bottoms that do not penetrate the body portion 3 or the threaded portion 4. Also, although the shape of the holes is shown as square in Figure 5, this is merely an example, and other shapes such as circles may be used. Furthermore, the number of holes is not limited to that shown in Figure 5. Specific examples of hole depths will be discussed later. In addition, the heat dissipation structure applied to the body portion 3 and the threaded portion 4 may be a combination of, for example, a fin shape as shown in Figures 3 and 4, and holes as shown in Figure 5.

[0022] As described above, the heat dissipation structure enhances the heat dissipation effect of the body 3 and screw portion 4, which are fitted with the heat dissipation structure, thereby suppressing deformation of the O-ring 6 attached to the metal valve 1 due to the heat generated when welding the outer casing 11 of the energy storage module 10. Now, let's explain the heat dissipation effect in more detail.

[0023] For example, the amount of heat Q released from a metal surface into the atmosphere is expressed by equation (1) "Q = S·λ·ΔT". Here, in equation (1), for example, S is the surface area of ​​the metal, λ is the thermal conductivity of the metal, and ΔT is the value obtained by subtracting the ambient temperature from the surface temperature of the metal. Therefore, according to equation (1), for example, the larger the surface area S of the metal, the larger the amount of heat released Q will be, and the higher the heat dissipation effect.

[0024] Using the body section 3 as an example, we will explain the heat dissipation effect with and without a heat dissipation structure. For example, let's assume that the radius of the cylindrical part of the cylindrical body section 3 is r and the length of the cylinder is 8 mm (millimeters) (note that in the following explanation, units of length and area may be omitted for convenience). In this case, the surface area of ​​the body section 3 is "2πr × 8 = 16πr", and for example, if r is 5.25, it becomes 84π. This is, for example, the surface area of ​​an unprocessed body section 3 without a heat dissipation structure.

[0025] On the other hand, consider the case where, for example, four grooves of depth x are cut into the body 3 as a heat dissipation structure. In this case, the surface area of ​​body 3 can be expressed by equation (2) "Surface area of ​​body 3 = Surface area of ​​the part without grooves + Surface area of ​​the grooved part + Surface area of ​​the side part of the grooves". Using equation (2), the specific value can be found as "(2πr × 4) + (2π(rx) × 4) + (πr 2 -π(rx) 2 ) × 6 = 16πr - 8πx + 12πrx - 6πx 2 For example, if the depth x is 0.5 and r is 5.25, then it becomes 110π. Comparing this to the surface area of ​​the unprocessed body 3, we get "110π / 84π = 1.309...", which means that an improvement in heat dissipation of approximately 30.9% can be expected.

[0026] Similarly, if the groove depth in the body 3 is 1.0 and r is 5.25, the surface area of ​​the body 3 will be 133π. Comparing this to the surface area of ​​the unprocessed body 3, we get "133π / 84π = 1.583...", indicating an improvement in heat dissipation of approximately 58.3%. Thus, the deeper the groove (or hole) in the body 3, the larger the surface area, and the greater the heat dissipation effect.

[0027] However, if grooves or holes are made deeper in the body 3 or threaded portion 4 to form a heat dissipation structure, the cross-sectional area of ​​the body 3 or threaded portion 4 will decrease accordingly. As a result, the shear stress applied to the cross-sectional area will be greater than in the unprocessed case, potentially leading to damage to the body 3 or threaded portion 4. In particular, for the threaded portion 4, even if the same tightening torque (also called "fastening torque") is applied to the threaded portion 4 before and after processing, the shear stress applied to the processed threaded portion 4, which has a reduced cross-sectional area, will be greater. When this shear stress reaches a limit value, the threaded portion 4 will break. Therefore, processing to form a heat dissipation structure requires that the shear stress applied to the body 3 or threaded portion 4 to which the heat dissipation structure is applied is within a range that does not damage the body 3 or threaded portion 4. Hereinafter, we will specifically explain how much the shear stress increases before and after processing to form a heat dissipation structure.

[0028] For example, assuming the outer diameter of the cylindrical portion of the cylindrical body part 3 is 10.5 and the inner diameter is 6.5, the cross-sectional area of the outer diameter portion is "πr 2 =5.25 2 π=approximately 27.56π", and the cross-sectional area of the inner diameter portion is "πr 2 =3.25 2 π=approximately 10.56π". Therefore, in this case, the cross-sectional area of the thick portion of the body part 3 is the area obtained by subtracting the cross-sectional area of the inner diameter portion from the cross-sectional area of the outer diameter portion, that is, 17π. Further, the shear stress T can be represented, for example, by formula (3) "T=F / A". Here, in formula (3), for example, F is a load, and A is a cross-sectional area. Therefore, the shear stress applied to the thick portion of the body part 3 is F / 17π. This is, for example, the shear stress applied to the thick portion of the unprocessed body part 3 that does not have a heat dissipation structure.

[0029] On the other hand, consider, for example, a case where a groove with a depth of 1 is dug in the body part 3 as a heat dissipation structure. In this case, the outer diameter of the groove portion is "10.5-(1×2)=8.5", so the cross-sectional area of the groove portion is "πr 2 =4.25 2 π=approximately 18.06π". Further, since the inner diameter of the groove portion does not change, the cross-sectional area of the inner diameter portion is approximately 10.56π, which is the same as in the unprocessed case. Therefore, the cross-sectional area of the thick portion of the groove portion is 7.5π, and the shear stress applied to the thick portion is F / 7.5π. When this is compared with the shear stress "F / 17π" in the unprocessed case, approximately 2.27 times the shear stress is applied to the thick portion of the groove portion.

[0030] Similarly, when a groove with a depth of 0.5 is dug in the body part 3, the outer diameter of the groove portion is "10.5-(0.5×2)=9.5", so the cross-sectional area of the groove portion is "πr 2 =4.75 2π = approximately 22.56π. Also, since the inner diameter of the groove remains unchanged at approximately 10.56π, the cross-sectional area of ​​the thickened portion of the groove becomes 12π, and the shear stress acting on this thickened portion is F / 12π. Comparing this to the shear stress "F / 17π" in the case of no processing, this is approximately 1.42 times the shear stress. Furthermore, the shear stress acting on the thickened portion of the groove is smaller when a groove with a depth of 0.5 is cut compared to when a groove with a depth of 1 is cut.

[0031] As explained above, the deeper the grooves or holes used as heat dissipation structures, the larger the surface area, which can lead to a higher heat dissipation effect. However, this also increases the shear stress on the body 3 and screw parts 4 where the heat dissipation structures are applied, which increases the likelihood of damage to the body 3 and screw parts 4.

[0032] The maximum amount of shear stress that can be tolerated to avoid damaging the body 3 and threaded portion 4 depends on the material and size of the body 3 and threaded portion 4 to which the heat dissipation structure is applied. For example, the shear stress after processing to form the heat dissipation structure is adjusted to be less than twice the shear stress before processing. This makes it possible to manufacture a metal valve 1 that can withstand normal use while obtaining a heat dissipation effect to suppress deformation of the O-ring 6.

[0033] More specifically, for example, grooves or holes with a depth Δ that satisfy the following equation (4) are provided in at least one of the body portion 3 and the threaded portion 4 as a heat dissipation structure. Equation (4) is, for example, "2.0 ≥ shear stress after processing / shear stress before processing = (F / π(R-Δ) 2 -πr 2 ) / (F / πR 2 -πr 2 )=R 2 -r 2 / (R-Δ) 2 -r 2 The value is ≤2.0. Here, in equation (4), for example, R is the radius of the outer diameter of the cylindrical part, and r is the radius of the inner diameter of the cylindrical part.

[0034] Based on the above, for example, the processing to form the heat dissipation structure on at least one of the body portion 3 and the threaded portion 4 is performed based on the shear stress applied to at least one of the body portion 3 and the threaded portion 4 to which the heat dissipation structure is applied. Furthermore, the processing is performed such that, for example, the shear stress after processing is at least twice the shear stress before processing.

[0035] In addition to the heat dissipation structure described above, to suppress heat conduction to the O-ring 6, the body portion 3 and threaded portion 4 can be made thinner than usual, while considering their durability, to reduce heat conductivity. Alternatively, the material of the body portion 3 and threaded portion 4 may be a material with low heat conductivity, such as stainless steel. That is, for example, at least one of the body portion 3 and threaded portion 4 can be made thinner than a predetermined standard value and / or made of a predetermined material with low heat conductivity.

[0036] According to the embodiment described above, the metal valve 1 comprises a welded portion 2, a body portion 3, and a threaded portion 4, and at least one of the body portion 3 and the threaded portion 4 has a heat dissipation structure for heat from the welded portion 2. Furthermore, this heat dissipation structure may be at least one of a fin shape and a hole. With such a metal valve 1, deformation of the O-ring 6 attached to the metal valve 1 due to the heat generated when welding the outer casing 11 of the energy storage module 10 can be suppressed.

[0037] Furthermore, the processing to form the heat dissipation structure is carried out based on the shear stress applied to at least one of the body portion 3 and the threaded portion 4 to which the heat dissipation structure is applied. More specifically, the processing to form the heat dissipation structure is carried out such that the shear stress after processing is less than or equal to twice the shear stress before processing. By processing the metal valve 1 in this way, it is possible to manufacture a metal valve 1 that can withstand normal use while obtaining a heat dissipation effect to suppress deformation of the O-ring 6.

[0038] Furthermore, at least one of the body portion 3 and the threaded portion 4 is made thinner than a predetermined standard value and / or made of a predetermined material with low heat conductivity. By producing the metal valve 1 in this way, heat conduction to the O-ring 6 can be further suppressed.

[0039] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of this disclosure are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of Symbols]

[0040] 1. Metal valve 2 Welded area 3 Torso 4. Screw part 5. Threaded portion 6 O-rings 10 Energy storage modules 11 Exterior 20 hot plate

Claims

1. The welded part and, Torso and, The screw part, The body portion and at least one of the screw portion have a heat dissipation structure for heat from the welded portion. Metal valve.

2. The metal valve according to claim 1, wherein the heat dissipation structure is at least one of a fin shape and holes.

3. The metal valve according to claim 1 or 2, wherein the processing for forming the heat dissipation structure is performed based on the shear stress applied to at least one of the body portion and the threaded portion to which the heat dissipation structure is applied.

4. The fact that the aforementioned processing is carried out based on the shear stress means that The processing is carried out such that the shear stress after processing is less than or equal to twice the shear stress before processing. The metal valve according to claim 3, including the following:

5. The metal valve according to claim 1 or 2, wherein at least one of the body portion and the threaded portion is made of a predetermined material that is thinner than a predetermined reference value and / or has low thermal conductivity.

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