A sealing device for testing the airtightness of battery packs

Abstract

This invention discloses a sealing device for testing the airtightness of battery packs, relating to the field of battery pack testing. The sealing device includes a mounting box, a plug, and a heating element. The mounting box has a receiving cavity with one open end. The plug, made of thermally responsive silicone material, is disposed within the receiving cavity. The heating element, also disposed within the receiving cavity, heats the plug. The plug exhibits reversible thermal response characteristics: upon heating, it undergoes plastic deformation to conform to the surface of the connector, and upon cooling, it solidifies and maintains its deformed state. By placing a plug made of thermally responsive silicone material within the mounting box, the plug softens during heating to fully fill the gaps in the connector, and upon cooling and solidifying, it tightly wraps around the gaps, ensuring the sealing stability of the connector during testing. Due to the reversible thermal response characteristics of the plug, it does not cause interface damage to the connector during sealing and disassembly.

Description

Technical Field

[0001] This utility model relates to the field of battery pack performance testing technology, and in particular to a sealing device for testing the airtightness of battery packs. Background Technology

[0002] In the new energy battery industry, the airtightness of the battery pack is a core element in ensuring the overall quality of the product. It is not only a necessary condition for meeting relevant national safety standards (such as GB / T 31467.3), but also directly affects the safe operation of the entire vehicle, the stability of battery performance, and the extension of its lifespan. Airtightness testing can promptly identify sealing defects in the battery pack manufacturing process, such as leaks in welds or loose interfaces, allowing for corrective measures to be taken to improve the reliability and durability of the entire vehicle. However, the accuracy of airtightness testing is highly dependent on the effectiveness of the connector sealing process; any improper sealing can lead to distorted test results, thereby affecting the overall quality control of the battery pack.

[0003] Currently, common connector sealing methods in the industry have significant drawbacks, mainly falling into two categories. First, rubber plug sealing methods are prone to material wear or permanent deformation during long-term use and repeated insertion and removal, leading to a decline in sealing performance. This is especially true for connectors with complex shapes (such as threaded or irregular holes) or high precision requirements, where rubber plugs struggle to achieve a perfect fit, increasing the risk of leakage. Second, while specialized sealing heads and mechanical clamps can provide high sealing performance, they require highly skilled operators, and improper installation can directly affect the sealing effect. Furthermore, these methods are costly to manufacture (e.g., due to precision machining requirements), and the clamping force of mechanical clamps can cause indentations or mechanical damage to the connector surface, affecting its appearance and lifespan. These limitations not only increase testing costs but also reduce production efficiency. Utility Model Content

[0004] In view of this, the present invention proposes a sealing device for testing the airtightness of battery packs, in order to solve the problems of inadequate sealing and easy interface damage caused by the complex shape of the plug-in components in traditional sealing devices.

[0005] The technical solution of this utility model is implemented as follows: This utility model provides a sealing device for testing the airtightness of a battery pack, the sealing device comprising: The mounting box has a receiving cavity that is open at one end; A plug is disposed within the receiving cavity, and the plug is made of a heat-responsive silicone material; A heating element, located within the accommodating cavity, is used to heat the plug. The plug has reversible thermal response characteristics: it can undergo plastic deformation after heating to fit the surface of the connector, and it solidifies and maintains the deformed state after cooling.

[0006] Based on the above technical solution, preferably, the softening temperature of the plug is 85-95℃ and the curing temperature is 25-40℃.

[0007] Based on the above technical solution, preferably, a gap is provided between the plug and the inner wall of the accommodating cavity to accommodate radial deformation when the plug and the connector are sealed.

[0008] Based on the above technical solution, preferably, an adjustment structure is provided between the plug and the mounting box to adjust the position of the plug in the axial direction of the accommodating cavity.

[0009] Based on the above technical solution, preferably, the adjustment structure includes a waist-shaped hole and a locking bolt. At least one waist-shaped hole is provided on each of the two opposite sides of the mounting box along the length of the plug. One end of the locking bolt passes through the waist-shaped hole and is threadedly fixed to the heating element. The locking bolt can move along the waist-shaped hole.

[0010] Based on the above technical solution, preferably, the adjustment structure further includes a mounting plate, the accommodating cavity is open at both ends, the mounting plate is disposed in the accommodating cavity and is fixedly connected to the side of the heating element away from the plug, and the locking bolt is threadedly fixedly connected to the heating element or the mounting plate.

[0011] Based on the above technical solution, preferably, an elastic pad is fixedly provided on the open end face of the mounting box.

[0012] Based on the above technical solution, preferably, the thermally responsive silicone contains 5-8 wt% boron nitride thermally conductive filler with a thermal conductivity ≥1.5 W / (m·K).

[0013] Based on the above technical solution, preferably, the top surface of the mounting box has an electrical control device, and the electrical control device is electrically connected to the heating element.

[0014] Based on the above technical solution, preferably, the plug sidewall is provided with at least one temperature sensor, and the temperature sensor is electrically connected to the electronic control device.

[0015] The present invention has the following advantages over the prior art: (1) The spatial relationship between the mounting box, the plug, and the heating element in this embodiment constitutes a dynamic response system: the heating element activates the thermoplasticity of the plug → the plug deformation is guided by the cavity → a directional sealing interface is formed. During the heating stage, the plug softens and can fully fill the gaps of the connector, while after cooling and solidification, it tightly wraps the gaps of the connector, ensuring the sealing stability of the connector during testing. Due to the reversible thermal response characteristics of the plug, the plug will not cause interface loss to the connector during the sealing and disassembly process.

[0016] (2) By setting an adjustment structure, the position of the plug in the axial direction of the accommodating cavity can be precisely controlled by mechanical limit, ensuring that only the sealing part contacts the plug when the plug is inserted. This achieves the reliability of fixed-length sealing, completely isolates the non-sealed area to avoid damage, and supports quick adaptation to plugs of different specifications. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a three-dimensional structural diagram of the sealing device disclosed in this utility model; Figure 2 This is a schematic diagram of the planar structure of the sealing device disclosed in this utility model; Figure 3 for Figure 2 Planar sectional view at point AA; Figure 4 This is a schematic diagram of the sealing device and connector disclosed in this utility model before they are assembled. Figure 5 This is a schematic diagram showing the state of the sealing device and connector after assembly according to this utility model. Figure label: S, Panel; P, Connector; 1, Mounting Box; 10, Receiving Cavity; 2, Plug; 3, Heating Component; 4, Adjustment Structure; 41, Waist-shaped Hole; 42, Locking Bolt; 43, Mounting Plate; 5, Elastic Pad; 6, Electrical Control Device; 7, Temperature Sensor. Detailed Implementation

[0019] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In the description of the embodiments of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this utility model based on the specific circumstances.

[0022] In the description of the embodiments of this utility model, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0025] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0026] like Figure 1 As shown, combined with Figure 2-5 This utility model discloses a sealing device for testing the airtightness of a battery pack. The sealing device includes a mounting box 1, a plug 2, and a heating element 3.

[0027] The mounting box 1, serving as the main support of the device, features a semi-enclosed working space formed by its open-end accommodating cavity 10. The sidewalls of the accommodating cavity 10 provide radial constraint for the plug 2, while the open end allows the plug 2 to directly contact the connector P to be sealed. When the plug 2 expands due to heat, the geometric boundaries of the accommodating cavity 10 guide the material to deform preferentially towards the opening (i.e., the connector P side). This directional expansion mechanism significantly improves the sealing accuracy. The structure of the accommodating cavity 10 ensures that the plug 2 remains in a controlled deformation state during operation, avoiding sealing failure caused by disordered expansion.

[0028] The plug 2 is disposed in the accommodating cavity 10 and is made of thermally responsive silicone material. The plug 2 has reversible thermal response characteristics: it can produce plastic deformation after heating to fit the surface of the plug P, and it can solidify and maintain the deformed state after cooling.

[0029] Specifically, thermoresponsive silicone is a high-molecular-weight elastomer based on polysiloxane. Its main molecular chain consists of repeating -Si-O- units, with side chains connected to organic groups (such as methyl and phenyl). This special structure endows the material with: thermoresponsiveness (significant movement of molecular chain segments near the glass transition temperature) and reversible deformation (reversible recombination of the cross-linked network during heating / cooling).

[0030] In this embodiment, the silicone material selected for the plug 2 is Dow Chemical's SILASTIC™ LC series or Dow Chemical's TPSiV™ 3005 / 3010.

[0031] Specifically, when the plug 2 is heated to its transition temperature, the molecular chain mobility of the material increases, resulting in decreased viscosity and enhanced plasticity. This state allows it to penetrate like "playdough" into the microscopic irregularities such as threads and cracks of the connector P. Traditional rubber, due to its elastic deformation, has difficulty achieving complete adhesion to these irregular shapes, thus creating a risk of air leakage. However, the reversible properties of the thermally responsive silicone material in this application allow it to maintain a preset deformation state after cooling and curing, ensuring sealing stability during testing.

[0032] After the plug 2 cools and solidifies, the material can adhere tightly to the irregular part of the connector P. At this time, the air tightness test of the battery pack can be performed to avoid the impact of air leakage at the connector P on the test results. After the air tightness test of the battery pack is completed, the plug 2 can be softened by heating it a second time. At this time, the plug 2 can be easily removed from the connector P. The softened plug 2 will not damage the surface of the connector P.

[0033] Heating element 3, disposed within the accommodating cavity 10, is used to heat the plug 2. Specifically, heating element 3 is positioned at the end of the plug 2 furthest from the end requiring sealing with the connector P. The heating element 3's heat conduction direction is coaxial with the deformation direction of the plug 2, ensuring uniform heat transfer across the entire working surface of the plug 2. Furthermore, the accommodating cavity 10 confines the heat within it, reducing heat loss and improving the heating efficiency of the plug 2. In this embodiment, heating element 3 can be configured as an electric heating plate, i.e., the plate's interior is constructed of heating wires.

[0034] In this embodiment, the spatial relationship between the mounting box 1, the plug 2, and the heating element 3 constitutes a dynamic response system: the heating element 3 activates the thermoplasticity of the plug 2 → the deformation of the plug 2 is guided by the receiving cavity 10 → forming a directional sealing interface. During the heating stage, the plug 2 softens and can fully fill the gaps of the connector P, while after cooling and solidification, it tightly wraps the gaps of the connector P, ensuring the sealing stability of the connector P during testing. Due to the reversible thermal response characteristics of the plug 2, the plug 2 will not cause interface loss to the connector P during the sealing and disassembly processes.

[0035] As some embodiments, the softening temperature of the plug 2 is 85-95℃, and the curing temperature is 25-40℃.

[0036] The softening temperature range of 85-95℃ is designed based on a dual consideration of the phase change characteristics of silicone material and the requirements of actual working conditions: at 85℃, the cross-linking bonds inside the material begin to break, and the molecular chains gain sufficient mobility to achieve plastic deformation; while the upper limit of 95℃ prevents the material from breaking molecular chains and causing permanent damage due to overheating. The curing temperature range of 25-40℃ ensures that the plug 2 maintains stable solid mechanical properties at most ambient temperatures, avoiding sealing failure due to environmental fluctuations.

[0037] In some embodiments, a gap is provided between the plug 2 and the inner wall of the accommodating cavity 10 to accommodate radial deformation of the plug 2 when sealing with the connector P. Specifically, when the connector P is inserted into the heated and softened plug 2, the material of the plug 2 will undergo radial displacement, preferentially filling the gap to ensure that the connector P can easily enter the interior of the plug 2 and avoid limiting the radial expansion of the plug 2.

[0038] Because the connector P has parts on the outside of the battery pack panel S that need to be sealed, such as the connector slot at the end of the connector P, which is the connection point with the communication harness connector, this connector slot has a certain depth. Other parts of the connector P do not need to be sealed. If they are sealed, it may have a certain impact on the connector P. Therefore, the connector P needs to be sealed at a fixed length. Since the plug 2 is located in the accommodating cavity 10, if the heated plug 2 is directly inserted into the connector P, it is difficult to control the depth of the connector P into the plug 2. This will cause the connector P to be inserted into the plug 2 too deeply or too shallowly.

[0039] To address the aforementioned problems, this embodiment provides the following technical solution.

[0040] In this embodiment, an adjustment structure 4 is provided between the plug 2 and the mounting box 1 to adjust the position of the plug 2 in the axial direction of the accommodating cavity 10.

[0041] Therefore, when the length of the connector P to be sealed is determined, for example, the total length of the connector P is L and the length to be sealed is L1, the position of the plug 2 in the receiving cavity 10 is adjusted by adjusting the structure 4, so that the sealing end face of the plug 2 is located inside the receiving cavity 10, and the distance between the sealing end face of the plug 2 and the opening end of the mounting box 1 is L1 + (1~2mm), where 1~2mm is a compensation amount. Thus, when the plug 2 is heated and softened, an insertion force is applied to the connector P, causing the connector P to be inserted into the plug 2. When the part of the connector P to be sealed is completely inserted into the plug 2, the end face of the mounting box 1 abuts against the panel S of the battery pack, thus determining the depth to which the connector P is inserted into the plug 2, ensuring that the plug 2 can seal the connector P to a fixed length.

[0042] By setting the adjustment structure 4, the position of the plug 2 in the axial direction of the accommodating cavity 10 can be precisely controlled by the mechanical limit, ensuring that only the sealing part of the connector P needs to contact the plug 2 when it is inserted. This achieves the reliability of fixed-length sealing, completely isolates the non-sealed area to avoid damage, and supports quick adaptation to connectors P of different specifications.

[0043] This embodiment discloses a structural method of the adjustment structure 4. Specifically, the adjustment structure 4 includes a waist-shaped hole 41 and a locking bolt 42. At least one waist-shaped hole 41 is provided on each of the two opposite sides of the mounting box 1 along the length direction of the plug 2. One end of the locking bolt 42 passes through the waist-shaped hole 41 and is threadedly fixed to the heating element 3. The locking bolt 42 can move along the waist-shaped hole 41.

[0044] Therefore, when the position of the plug 2 needs to be adjusted, the locking bolt 42 is loosened to eliminate the fastening force between the locking bolt 42 and the outer wall of the mounting box 1. The entire assembly consisting of the heating element 3 and the plug 2 is moved axially along the receiving cavity 10 by moving the locking bolt 42. When the plug 2 is moved to the appropriate position, the locking bolt 42 is tightened to secure and lock the heating element 3 and the mounting box 1, ensuring the positional accuracy of the plug 2 in the receiving cavity 10.

[0045] In some other embodiments, the adjustment structure 4 also includes a mounting plate 43. The accommodating cavity 10 is open at both ends. The mounting plate 43 is disposed in the accommodating cavity 10 and is fixedly connected to the side of the heating element 3 away from the plug 2. The locking bolt 42 is threadedly fixedly connected to the heating element 3 or the mounting plate 43.

[0046] With this configuration, when the position of the plug 2 needs to be adjusted, the locking bolt 42 can be loosened, and the mounting plate 43 can be manually pushed to move the heating element 3 and the plug 2 within the accommodating cavity 10 along the axial direction of the accommodating cavity 10. This method is more labor-saving and convenient than moving the locking bolt 42.

[0047] In this embodiment, the mounting box 1 is made of high-temperature resistant metal material, which has a certain rigidity. An elastic pad 5 is fixedly provided on the open end face of the mounting box 1. Therefore, when the mounting box 1 and the panel S abut, the elastic pad 5 can buffer the impact and prevent the mounting box 1 and the panel S from undergoing rigid collision and wear.

[0048] To rapidly achieve the heating and softening of the plug 2, this embodiment incorporates 5-8 wt% boron nitride thermally conductive filler in the thermally responsive silicone rubber, with a thermal conductivity ≥1.5 W / (m•K). The three-dimensional thermally conductive network formed by the boron nitride ensures rapid and uniform heat distribution, eliminates the risk of localized overheating, improves heat transfer efficiency, and ensures that the plug 2 is rapidly heated and softened within a short time.

[0049] In some embodiments, the top surface of the mounting box 1 has an electrical control device 6, which is electrically connected to the heating element 3. The electrical control device 6 can be used to start or stop the heating function, and can also adjust the heating temperature and time of the heating element 3. In this embodiment, the electrical control device 6 includes a power supply, a controller, a switch, and a temperature adjustment button. These are electrically connected to each other.

[0050] In some implementations, at least one temperature sensor 7 is provided on the side wall of the plug 2, and the temperature sensor 7 is electrically connected to the electronic control device 6. The temperature sensor 7 can obtain the temperature at which the plug 2 softens when heated, and the heating can be automatically or manually turned off according to the temperature to prevent temperature overload and irreversible internal structural changes in the plug 2 material.

[0051] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A sealing device for testing the airtightness of a battery pack, characterized in that, The sealing device includes: Mounting box (1), which has a receiving cavity (10) open at one end; A plug (2) is disposed in the receiving cavity (10), and the plug (2) is made of thermally responsive silicone material; A heating element (3) is disposed in the accommodating cavity (10) and is used to heat the plug (2); The plug (2) has reversible thermal response characteristics: it can produce plastic deformation after heating to fit the surface of the plug (P), and solidify and maintain the deformed state after cooling.

2. The sealing device for battery pack airtightness testing as described in claim 1, characterized in that: The softening temperature of the plug (2) is 85-95℃, and the curing temperature is 25-40℃.

3. The sealing device for battery pack airtightness testing as described in claim 1, characterized in that: A gap is provided between the plug (2) and the inner wall of the accommodating cavity (10) to accommodate radial deformation when the plug (2) seals with the connector (P).

4. The sealing device for battery pack airtightness testing as described in claim 1, characterized in that: An adjustment structure (4) is provided between the plug (2) and the mounting box (1) for adjusting the position of the plug (2) in the axial direction of the accommodating cavity (10).

5. The sealing device for battery pack airtightness testing as described in claim 4, characterized in that: The adjustment structure (4) includes a waist-shaped hole (41) and a locking bolt (42). At least one waist-shaped hole (41) is provided on each of the two opposite sides of the mounting box (1) along the length of the plug (2). One end of the locking bolt (42) passes through the waist-shaped hole (41) and is threadedly fixed to the heating element (3). The locking bolt (42) can move along the waist-shaped hole (41).

6. The sealing device for battery pack airtightness testing as described in claim 5, characterized in that: The adjustment structure (4) also includes a mounting plate (43). The accommodating cavity (10) is open at both ends. The mounting plate (43) is disposed in the accommodating cavity (10) and is fixedly connected to the heating element (3) on the side away from the plug (2). The locking bolt (42) is threadedly fixedly connected to the heating element (3) or the mounting plate (43).

7. The sealing device for battery pack airtightness testing as described in claim 4, characterized in that: An elastic pad (5) is fixedly provided on the open end face of the mounting box (1).

8. The sealing device for battery pack airtightness testing as described in claim 1, characterized in that: The thermally responsive silicone contains 5-8 wt% boron nitride thermally conductive filler with a thermal conductivity ≥1.5 W / (m•K).

9. The sealing device for battery pack airtightness testing as described in claim 1, characterized in that: The mounting box (1) has an electrical control device (6) on its top surface, and the electrical control device (6) is electrically connected to the heating element (3).

10. The sealing device for battery pack airtightness testing as described in claim 9, characterized in that: At least one temperature sensor (7) is provided on the side wall of the plug (2), and the temperature sensor (7) is electrically connected to the electronic control device (6).

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