Process method for automatically removing bubbles and enhancing heat conduction in encapsulation and encapsulation structure
By using layered potting and gravity settling methods, a high thermal conductivity layer is formed on the surface of electronic components using heavy inert fillers. This solves the problems of reduced thermal conductivity and insulation performance caused by air bubbles in the potting process, achieving a high-efficiency and low-cost potting effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-04-10
AI Technical Summary
The presence of air bubbles in existing potting processes leads to decreased thermal conductivity, reduced insulation performance, and weakened protective capabilities, and also increases costs and time due to the reliance on specialized equipment and complex processes.
By adopting the principle of natural sedimentation of heavy inert fillers, and through layered pouring and static curing, the density difference is used to make the filler particles settle under the action of gravity, drive the air bubbles to float and form a highly thermally conductive layer on the surface of electronic components, simplifying the process and reducing costs.
It achieves excellent de-bubbling effect, significantly improves heat dissipation performance and insulation stability, simplifies the process, reduces production costs, and improves production efficiency and product reliability.
Smart Images
Figure CN121843565A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electronic product packaging technology, specifically to a potting process and structure for automatically removing air bubbles and enhancing thermal conductivity. Background Technology
[0002] Electronic products, especially power devices, generate a lot of heat during operation. They are typically encapsulated using potting processes to achieve insulation, moisture protection, dust protection, heat dissipation, and mechanical protection. Currently, the most commonly used potting materials are two-component potting compounds such as epoxy resin or silicone.
[0003] In traditional potting processes, the mixing of components A and B of the potting compound inevitably introduces a large number of air bubbles. If these bubbles remain in the cured compound, they will form voids, such as… Figure 5 As shown. This causes the following serious problems: 1. Decreased thermal conductivity: Gases have low thermal conductivity, and the presence of bubbles will severely hinder the conduction path of heat from electronic components to the casing, leading to localized overheating and affecting product performance and lifespan.
[0004] 2. Reduced insulation performance: Air bubbles reduce the overall insulation strength of the colloid, which may cause arcing or breakdown under high voltage conditions.
[0005] 3. Reduced protective ability: Holes and gaps provide channels for moisture to enter, which may cause internal circuits to become damp and short-circuit.
[0006] To address the bubble problem, existing technologies typically employ physical methods for degassing, such as placing the mixed adhesive in a vacuum degassing machine for vacuum treatment before potting, or using an integrated mixing and degassing machine. However, these methods have significant drawbacks: they increase the need for dedicated mixing and vacuum equipment, raising production and maintenance costs; they prolong production processes and time, reducing production efficiency; and for high-viscosity potting compounds, the degassing effect is not ideal. Summary of the Invention
[0007] In view of this, and considering the problems of existing potting processes relying on specialized equipment to remove air bubbles, which are complex and costly, the purpose of this invention is to provide a potting process and structure that automatically removes air bubbles and enhances thermal conductivity.
[0008] This method utilizes the natural settling principle of heavy inert fillers (such as quartz sand) to automatically remove air bubbles during the potting process without the need for vacuum degassing equipment. It can also build a high thermal conductivity layer on the surface of electronic components, thereby simplifying the process, greatly reducing costs, and improving the heat dissipation performance and reliability of the product.
[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a process method for automatically de-bubbling and enhancing thermal conductivity during potting, comprising the following steps: S1: Prepare filler mixture by mixing heavy inert filler particles with liquid curing polymer potting compound in a preset ratio; S2: Using a layered injection method, first inject standard potting compound without filler into the shell to form a first layer, and then inject the filler mixture onto the first layer to form a second layer, wherein the injection amounts of the standard potting compound and the filler mixture meet a preset ratio; S3: Static curing. Utilizing the density difference between the heavy inert filler particles and the colloid, the filler particles settle under gravity. During the settling process, physical compression drives the air bubbles to float and be discharged, while simultaneously enriching and forming a highly thermally conductive layer on the surface of electronic components.
[0010] In some embodiments, the density of the heavy inert filler particles is 1.5 to 2.0 g / cm³, and the mesh size is 70 to 120 mesh.
[0011] In some embodiments, the heavy inert filler particles are selected from at least one of quartz sand, cobblestone crushed sand, ordinary river sand, or glass fragments.
[0012] In some embodiments, 5. the process method according to claim 1, characterized in that the specific steps for preparing the filler mixture in step S1 include: S11: The heavy inert filler particles and the resin component (component A) of the liquid-curing polymer potting compound are mixed for the first time at a mass ratio of (0.8-1.2):1, and stirred until uniform. S12: Add component B according to the specified curing agent component (i.e., component B) addition ratio of the liquid curing polymer potting compound, and mix for a second time. Stir evenly to obtain the filler mixture.
[0013] In some embodiments, in step S2, the mass ratio of the standard potting compound to the filler mixture is 1:(2-4).
[0014] In some embodiments, in step S2, after each layer of adhesive is poured, a static leveling process is performed.
[0015] In some embodiments, in step S3, the static curing is carried out at room temperature.
[0016] In some embodiments, the method is applicable to the potting and encapsulation of electronic components in photovoltaic inverters, power modules, or controllers.
[0017] Secondly, this application provides a potting structure, which is prepared by any of the processes described above, including a first adhesive layer and a second adhesive layer arranged sequentially from bottom to top, and a highly thermally conductive layer composed of sedimented and enriched heavy inert filler particles is formed on the surface of the electronic component, with no air bubbles inside the colloid.
[0018] The beneficial effects of the automatic de-bubbling and thermal conductivity enhancement process and potting structure disclosed in this application may include, but are not limited to: 1. Achieved excellent debubbling effect at low cost. Traditional processes rely on expensive vacuum degassing equipment (such as vacuum mixers) to remove air bubbles, resulting in high equipment investment and maintenance costs. This invention completely eliminates the need for dedicated degassing equipment. Instead, it utilizes the natural settling of inexpensive heavy fillers (such as silica sand) with specific mesh size and density under gravity to continuously physically compress and drive air bubbles out during the curing process.
[0019] 2. Significantly improved the overall heat dissipation performance of the potting compound. Traditional homogeneous potting or simple mixed potting has limited thermal conductivity. This invention utilizes a layered potting and sedimentation enrichment mechanism to spontaneously form a densely packed "enriched thermally conductive layer" of highly thermally conductive filler particles on the surface of electronic components (such as IGBTs). This layer constitutes a highly efficient thermal conduction framework network. Tests show that the potting compound prepared by this invention achieves an effective thermal conductivity of 0.98-1.22 W / m·K, which is more than three times that of traditional pure glue potting (approximately 0.35 W / m·K, Comparative Example 1), effectively reducing the operating temperature of power devices and improving product lifespan and reliability.
[0020] 3. It simplifies the process and improves production efficiency. Existing technologies typically involve multiple processes such as "mixing-vacuum degassing-pouring-curing," resulting in long production cycles. This invention combines the degassing and curing processes into one, simplifying the process to "special mixing-layered pouring-static curing," eliminating the need for waiting for vacuuming time and requiring no equipment operation or transfer.
[0021] 4. Enhanced long-term reliability and insulation stability of the product. Residual air bubbles are a major pathway leading to insulation degradation and moisture intrusion. The extremely high density and void-free structure achieved in this invention fundamentally eliminates these risks. Test results show that its insulation strength (>26kV / mm) is significantly higher than that of traditional processes and comparative studies with air bubbles. Simultaneously, the dense filler-rich layer at the bottom enhances resistance to mechanical stress and thermal cycling shock, providing more robust protection for the internal precision circuitry.
[0022] 5. Achieved the best balance between performance, cost, and manufacturability. This invention does not simply replace part of the colloid with filler. Instead, it employs a meticulously designed synergistic system of "filler pretreatment - layering ratio - sedimentation and curing" to ensure excellent defoaming and thermal conductivity while avoiding a series of process problems that may arise from filler addition, such as a sharp increase in viscosity, poor leveling, or excessively fast or slow sedimentation. It uses extremely low-cost, widely available insulating mineral particles to replace expensive specialized thermally conductive fillers, making high-performance potting no longer dependent on high-cost materials, thus possessing extremely high market competitiveness and promotional value.
[0023] In summary, this invention creatively applies the fundamental physical principle (gravity settling) to the potting process. Through a series of cleverly linked technical means, it simultaneously and efficiently solves several long-standing technical problems in the potting field, such as bubble elimination, enhanced heat dissipation, cost control, and process simplification, providing an innovative solution with both outstanding substantive features and significant economic value. Attached Figure Description
[0024] Figure 1 : A schematic diagram of the process method of the present invention.
[0025] Figure 2 : Schematic diagram of the first layer of "standard potting compound" being poured. The diagram shows that the first layer 100 formed by pure adhesive covers the electronic component 101.
[0026] Figure 3 : Schematic diagram of pouring the second layer of "filler mixture". The diagram shows that the second adhesive layer 200 containing filler particles 201 covers the first adhesive layer 100.
[0027] Figure 4 : Schematic diagram of dynamic principle. The arrows in the diagram illustrate the dynamic replacement process of filler particles 201 sinking and air bubbles rising.
[0028] Figure 5 : Schematic diagram of existing technology. It shows that after curing using traditional methods, a large number of air bubbles remain inside the colloid.
[0029] Figure 6 : Schematic diagram of the effect of the present invention. It shows that after curing, the filler particles 201 form a dense enriched layer at the bottom, and there are no air bubbles inside the colloid. Detailed Implementation
[0030] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, materials, or methods have not been specifically described in order to avoid obscuring the invention.
[0031] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example.
[0032] Furthermore, specific features, structures, or properties can be combined in one or more embodiments or examples in any suitable combination and or sub-combination.
[0033] Example 1: like Figure 1 As shown, a process for automatically de-bubbling and enhancing thermal conductivity in potting involves utilizing the density difference between heavy, inert filler particles and the potting compound. Through a specific layered potting process, the filler particles spontaneously settle during the static curing process. This settling process not only physically compresses and drives air bubbles to rise and be expelled, achieving automatic de-bubbling, but also enriches the filler particles on the surface of the electronic components at the bottom, forming a dense, highly thermally conductive layer. This simultaneously solves the two major problems of residual air bubbles and poor heat dissipation.
[0034] The purpose of each part of the technical solution of this invention, the beneficial effects achieved, and the working principle are explained in detail below: In order to construct the above-mentioned integrated mechanism of "de-bubbling and enrichment of heat conduction" based on gravity sedimentation, the core process steps of this invention include: preparation of filler mixed adhesive (S1), layered pouring (S2), and static curing (S3).
[0035] The purpose of step S1 is to pre-disperse the filler in the colloid to form the "source" material for subsequent sedimentation. If dry filler is added directly, it is difficult to disperse it evenly and it is easy to trap more air bubbles.
[0036] The purpose and principle of step S2 (layered potting): First, a filler-free "standard potting compound" is poured to form the first layer. This is to utilize its excellent flowability to fully wet and fill the tiny gaps at the bottom of the housing and between components, laying a good interfacial contact foundation for the subsequent formation of the thermally conductive layer. For example... Figure 2 As shown.
[0037] The re-injection of the "filler mixture" to form a second adhesive layer is to establish a concentration gradient (actually a density gradient) within the adhesive, from the high filler content region (upper layer) to the low filler content region (lower layer). This is the initial condition for driving the directional and orderly sedimentation of the filler particles in step S3. If the mixture is injected all at once, the filler distribution is relatively uniform from the beginning, the sedimentation driving force is weak, and a distinct bottom enrichment layer cannot be formed. Figure 3 As shown.
[0038] The purpose and mechanism of step S3 (static curing): In this stage, no external mechanical or vacuum intervention is applied; it relies purely on the physical action of gravity. Because the density of the filler particles (typically 1.5-2.0 g / cm³) is greater than that of the surrounding colloid (typically 1.5-1.75 g / cm³), they begin to slowly sink under gravity. The sinking particles collide, compress, and carry tiny air bubbles (with a much lower density than the colloid) that are encapsulated in the colloid or attached to the particle surface along their path, forcing the bubbles to migrate upwards and eventually overflow the liquid surface. This is the "physical extrusion defoaming" mechanism. Figure 4 As shown.
[0039] Meanwhile, the continuously settling particles eventually accumulate at the bottom, especially on the surface of electronic components, forming a densely packed "skeleton" structure of filler. After curing, these interconnected, highly thermally conductive filler particles construct an efficient three-dimensional heat conduction network, while the cured adhesive filling their gaps provides insulation and mechanical fixation, thus achieving the effect of "enhanced thermal conductivity." Figure 6 As shown.
[0040] To optimize the settling process and the performance of the final thermally conductive layer, the density of the heavy inert filler particles is limited to 1.5–2.0 g / cm³, and the mesh size is limited to 70–120 mesh.
[0041] Density is a key factor driving sedimentation. If the density is below 1.5 g / cm³, the density difference with the colloid is too small, resulting in a slow sedimentation rate. This may lead to incomplete sedimentation before the colloidal gel solidifies, affecting defoaming and enrichment effects. If the density is above 2.0 g / cm³, although sedimentation is fast, it may be too rapid, resulting in insufficient filler in the upper layer of the colloid. Furthermore, excessively heavy particles may cause excessive disturbance to the initially leveled first layer of colloid at the end of the sedimentation process. The range of 1.5–2.0 g / cm³ ensures moderate and controllable sedimentation kinetics.
[0042] Mesh size (particle size) affects packing density and interface. Particles of 70–120 mesh (approximately 125–212 micrometers) are of moderate size. Particles that are too coarse (too low mesh size), while providing a direct heat conduction path, have a rapid settling velocity, easily creating a "sandfall" effect, disrupting the adhesive layer, and potentially resulting in a rough, uneven enrichment layer on the component surface, affecting tight contact. Particles that are too fine (too high mesh size) have a huge specific surface area, significantly increasing the viscosity of the colloid, hindering bubble rise and particle settling, and even preventing the colloid from leveling properly. This mesh size range ensures good thermal conductivity while balancing processability and the density of the final cured body.
[0043] In order to maximize cost advantage and ensure reliability while achieving functionality, the heavy inert filler particles are limited to at least one selected from quartz sand, cobblestone crushed sand, ordinary river sand or glass fragments.
[0044] These materials are all widely available in nature or are industrial byproducts, making them extremely inexpensive and perfectly aligning with one of the core ideas of this invention: "achieving high-end functions with low-cost materials." Furthermore, they possess chemical inertness (do not react harmfully with potting compounds), electrical insulation (ensuring the insulation performance of the potting compound), and good thermal conductivity (their thermal conductivity is much higher than that of colloids and air), fully meeting the basic requirements for potting materials.
[0045] To ensure compatibility with the filler settling process and the overall performance of the final product, the liquid-curing polymer potting compound is limited to epoxy resin potting compound or silicone potting compound.
[0046] These two are the most commonly used and technologically mature adhesives in the field of electronic potting. They undergo an irreversible curing reaction at room temperature or under heating conditions to form a solid, providing the final "anchoring" for filler particles. Their viscosity range before curing allows the filler particles to settle smoothly within them. The choice of conventional adhesives further demonstrates the good compatibility of this invention with existing production systems, eliminating the need to change the main adhesive material.
[0047] To ensure that the filler achieves the optimal initial dispersion state in the colloid and minimizes the introduction of air bubbles, the preparation steps of the filler mixture are specified as a two-step method: first, the filler and component A (resin) are mixed at a mass ratio of (0.8~1.2):1, and then component B (curing agent) is added.
[0048] The principle and benefits of the first-step ratio (0.8–1.2):1: This ratio aims to achieve sufficient pre-wetting of the filler particle surface. The viscosity of the resin component (A glue) is usually lower than that of the mixed colloid. At this ratio, sufficient resin coats each filler particle, expelling air from between particles and forming a uniform "paste" premix. If the ratio is lower than 0.8, the amount of resin is insufficient, the filler is not adequately wetted, and it is dry and prone to clumping; if the ratio is higher than 1.2, the mixture system is too thin. Although the wetting is good, the overall viscosity after subsequent mixing with B glue may be too low, affecting the stratification effect. 1:1 is the best balance point between wettability and subsequent process viscosity, and a 20% fluctuation provides an operable process window.
[0049] The advantage of the two-step method: mixing with adhesive A first ensures that the filler is completely encapsulated by the resin before curing. If adhesives A and B are mixed first and then the filler is added, the colloid will begin to crosslink and thicken while the filler is being stirred, making it difficult to wet the filler and trapping a large number of air bubbles, which completely contradicts the original intention of this invention.
[0050] To construct the optimal filler concentration gradient during the potting stage, thereby obtaining an ideal adhesive layer structure and filler distribution after curing, the potting mass ratio of the standard potting compound to the filler mixture is limited to 1:(2-4).
[0051] This ratio determines the total volume fraction of filler in the final colloid and the relative thickness of the upper and lower adhesive layers. If the filler-to-colloid ratio is too low (e.g., less than 2), the total amount of filler in the system is insufficient, resulting in a thin bottom thermally conductive layer after settling and limited thermal enhancement effect. If the ratio is too high (e.g., greater than 4), the first pure adhesive layer is relatively thin and may not be able to fully fill all the complex gaps at the bottom, and the upper layer is too viscous, which may hinder the final escape of air bubbles. 1:3 is a proven optimal ratio, ensuring that the bottom has a sufficiently thick pure adhesive layer to complete the sealing and initial encapsulation, while the upper layer provides sufficient filler to form a significantly thick enriched thermally conductive layer. The range of 1:(2~4) covers the feasible process adjustment space.
[0052] To ensure that each layer of adhesive fully covers the predetermined area and forms a smooth interface, creating uniform initial conditions for subsequent settling, a static leveling treatment is performed after each layer of adhesive is poured.
[0053] Static leveling eliminates turbulence, ripples, or localized bulges caused by the pouring process, resulting in a more level and uniformly thick adhesive layer. This is crucial for the uniform and vertical settling of filler particles. An uneven interface leads to inconsistent settling path lengths, affecting the uniformity of the final thermally conductive layer distribution.
[0054] To completely eliminate expensive and complex specialized equipment and simplify the process, the curing process is specified to be carried out at room temperature or a specified temperature, and no vacuum degassing equipment is required throughout the process.
[0055] This is the most significant feature that distinguishes this invention from traditional technologies. Its principle relies entirely on the aforementioned physical mechanism of gravity sedimentation. At a specified curing temperature, which could be room temperature or a preheated temperature set to accelerate curing (e.g., a few degrees higher than room temperature, accelerating curing while allowing air bubbles to escape), the colloid undergoes chemical cross-linking and curing, while physical sedimentation occurs simultaneously. The entire process eliminates the need for vacuum tanks, agitators, degassing machines, etc., greatly reducing equipment investment, maintenance costs, and energy consumption, simplifying operation steps, and improving production efficiency.
[0056] To clarify the advantageous application scenarios of the present invention, the scope of application of the method is limited to the potting and encapsulation of electronic components in photovoltaic inverters, power modules or controllers.
[0057] The power devices (such as IGBTs and MOSFETs) in these devices generate a lot of heat, requiring extremely high levels of heat dissipation and reliability, while also facing fierce cost competition. The "high-performance, low-cost, and simplified process" solution provided by this invention precisely matches the core needs of these fields, demonstrating significant practical value and market prospects.
[0058] To protect the final product of this invention, a potting structure is defined, which is prepared by any of the above methods and has a characteristic structure consisting of a first adhesive layer, a second adhesive layer, and a bottom high thermal conductivity enrichment layer from bottom to top.
[0059] This structure is the tangible embodiment and inevitable result of the method of this invention. The first adhesive layer (pure adhesive layer) is dense and bubble-free, providing excellent bottom-layer sealing, insulation, and stress buffering; the second adhesive layer has very few bubbles after curing; most importantly, the high thermal conductivity enrichment layer formed on the surface of the heat source acts like a built-in "heat dissipation substrate," greatly reducing thermal resistance. This gradient functional structure of "dense at the bottom and sparse at the top, conductive at the bottom and protective at the top" cannot be achieved by traditional homogeneous potting or simple mixed potting, and it structurally guarantees the product's high reliability, long lifespan, and excellent heat dissipation performance.
[0060] The following examples all use an aluminum housing (internal volume of about 500cm³) to encapsulate an IGBT module of a simulated photovoltaic inverter.
[0061] Example 1 Step 1: Material Selection Heavy inert filler: 95-mesh high-purity quartz sand with a density of approximately 1.65 g / cm³ is selected.
[0062] Encapsulating compound: A two-component epoxy resin encapsulating compound is selected (A component density 1.55 g / cm³, B component density 1.10 g / cm³, and the density after mixing is approximately 1.45 g / cm³), with an A:B mass ratio of 3:1.
[0063] Step 2: Preparation of adhesive compound Standard potting compound: Weigh and mix A:B = 3:1 until homogeneous.
[0064] Filler-mixed adhesive: Weigh the quartz sand and epoxy resin A, mix them at a mass ratio of 1:1, and stir at high speed for 5 minutes until a uniform paste is formed.
[0065] Add the corresponding amount of B adhesive to the above paste according to the total adhesive ratio A:B=3:1, and stir again at medium speed for 3 minutes to obtain the filler mixture.
[0066] Step 3: Layered Infusion Calculate the required amount of adhesive based on a standard potting compound: filler mixture ratio of 1:3 by total mass.
[0067] First layer: Inject all the calculated standard potting compound into the housing, let it stand for 10 minutes until it flows naturally and completely covers the bottom heating element.
[0068] Second layer: Inject all the calculated filler mixture into the first layer, covering the surface of the filling, and let it stand for 15 minutes to level.
[0069] Step 4: Curing The potted product was placed at room temperature (25°C) for 24 hours to cure. No vacuuming or stirring was performed during the curing process.
[0070] Example 2 Step 1: Material Selection Heavy inert filler: 70-mesh cleaned and dried river sand with a density of approximately 1.50 g / cm³ is selected.
[0071] Encapsulating compound: The same two-component epoxy resin encapsulating compound as in Example 1.
[0072] Step 2: Preparation of adhesive compound Standard potting compound: The preparation method is the same as in Example 1.
[0073] Filler mixture: Mix river sand and A glue at a mass ratio of 0.8:1, then add B glue and stir.
[0074] Everything else is the same as in Example 1.
[0075] Step 3: Layered Infusion The potting compound and filler mixture should be mixed in a total mass ratio of 1:2 according to the standard.
[0076] The injection and settling steps are the same as in Example 1.
[0077] Step 4: Curing The curing conditions are the same as in Example 1.
[0078] Example 3 This embodiment uses a larger value of some parameters within the scope of the claims to verify the validity of the upper limit of the scope.
[0079] Step 1: Material Selection Heavy inert filler: 120-mesh spherical glass microspheres with a density of approximately 2.00 g / cm³ are selected.
[0080] Encapsulating compound: The same two-component epoxy resin encapsulating compound as in Example 1.
[0081] Step 2: Preparation of adhesive compound Standard potting compound: The preparation method is the same as in Example 1.
[0082] Filler mixture: Mix glass shards and adhesive A at a mass ratio of 1.2:1, then add adhesive B and stir. Other steps are the same as in Example 1.
[0083] Step 3: Layered Infusion The potting compound and filler mixture were mixed at a total mass ratio of 1:4. The potting and settling procedures were the same as in Example 1.
[0084] Step 4: Curing To expedite production, the product was cured in a 60°C oven for 4 hours. No vacuuming or stirring was performed during the curing process.
[0085] Comparative Example Comparative Example 1 (Traditional Vacuum Degassing Process) This comparative example uses the existing common process described in the background art.
[0086] Procedure: Use the same epoxy resin potting compound as in Example 1, but without adding any fillers. Mix the A and B compounds and place them in a planetary mixer for degassing at a vacuum of -0.095 MPa for 5 minutes. Then, inject the degassed compound into the shell in one go, allow it to stand and level, and cure it under the same conditions (25°C, 24 hours). This process represents a conventional "equipment-based, filler-free" method.
[0087] Comparative Example 2 (single mixed infusion, no stratification) This comparative example violates the core step of the "layered injection" method of this invention and is used to verify the necessity of the layered structure. Steps: The same materials (quartz sand, epoxy resin) and total proportions (the total mass ratio of sand and resin is the same as in Example 1) are used. However, all quartz sand, A-resin, and B-resin are mixed all at once, stirred, and directly injected into the shell until full. After standing and leveling, it is cured under the same conditions. This process represents a simple mixing process "with filler, without layering".
[0088] Comparative Example 3 (using filler outside the range) This comparative example uses filler parameters that do not meet the requirements of this invention to verify the importance of parameter limitations. Procedure: The same adhesive and layering ratio as in Example 1 were used. However, the filler used was 300-mesh (approximately 48 μm) high-purity quartz powder with a density of approximately 1.65 g / cm³. The preparation and pouring steps were the same as in Example 1. This process represents a case of "layering but with excessively fine filler".
[0089] IV. Comparison and Analysis of Results The samples from the above embodiments and comparative examples were tested, and the results are summarized in Table 1 below: Table 1
[0090] Effect Analysis: Compared with Comparative Example 1 (traditional process): In the three examples, without the need for vacuum equipment, the bubble area ratio (all <0.3%) was much lower than that of Comparative Example 1 (1.5%) after traditional vacuum degassing, proving that the effectiveness of the "sedimentation degassing" mechanism of this invention far exceeds that of traditional "vacuum degassing". At the same time, due to the formation of a highly thermally conductive enriched layer at the bottom, the thermal conductivity of the examples is more than 3 times that of Comparative Example 1, achieving a qualitative leap in heat dissipation performance.
[0091] Compared to Comparative Example 2 (without stratification): Comparative Example 2 had a bubble content as high as 8% and the lowest insulation strength, proving that one-time mixing and pouring introduces and locks in a large number of bubbles in the colloid, and the filler cannot effectively accumulate in a directional manner at the heat source. This proves that the stratified structure of the present invention, which involves "filling the gap with pure glue first, and then settling the filler glue", is an indispensable key to achieving both "low bubble" and "high thermal conductivity".
[0092] Compared to Comparative Example 3 (with excessively fine filler): Comparative Example 3 used 300-mesh ultrafine filler, whose huge specific surface area caused a sharp increase in the viscosity of the adhesive, severely hindering the rise of bubbles and the sedimentation of particles. Its effect was between that of the conventional process and the present invention, but far worse than the example, proving that the filler particle size (70-120 mesh) is an important parameter range for ensuring sedimentation kinetics and the final effect.
[0093] Comparison among examples: Example 1 (intermediate parameters) exhibits the best overall performance. Example 2 (lower limit parameters) has slightly weaker thermal conductivity due to less filler and coarser particles, but it is still significantly better than all comparative examples. Example 3 (upper limit parameters) has the best thermal conductivity due to its high filler density and content, and it also cures faster. All three examples successfully achieved the core objective of this invention, demonstrating the effectiveness and feasibility of the parameter ranges described in the claims.
[0094] In summary, this invention combines heavy filler with specific parameters with a layered injection process, which simplifies the process and reduces costs while achieving de-bubbling and heat dissipation performance far exceeding that of traditional processes. It has outstanding substantive features and significant progress.
[0095] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.
Claims
1. A process for automatically de-bubbling and enhancing thermal conductivity during potting, characterized in that, Includes the following steps: S1: Prepare filler mixture by mixing heavy inert filler particles with liquid curing polymer potting compound in a preset ratio; S2: Using a layered injection method, first inject standard potting compound without filler into the shell to form a first layer, and then inject the filler mixture onto the first layer to form a second layer, wherein the injection amounts of the standard potting compound and the filler mixture meet a preset ratio; S3: Static curing. Utilizing the density difference between the heavy inert filler particles and the colloid, the filler particles settle under gravity. During the settling process, physical compression drives the air bubbles to float and be discharged, while simultaneously enriching and forming a thermally conductive layer on the surface of electronic components.
2. The process method according to claim 1, characterized in that, The density of the heavy inert filler particles is 1.5 to 2.0 g / cm³, and the mesh size is 70 to 120 mesh.
3. The process method according to claim 1 or 2, characterized in that, The heavy inert filler particles are selected from at least one of quartz sand, cobblestone crushed sand, ordinary river sand, or glass fragments.
4. The process method according to claim 1, characterized in that, The liquid-curing polymer potting compound is an epoxy resin potting compound or an organosilicon potting compound.
5. The process method according to claim 1, characterized in that, The specific steps for preparing the filler mixture in step S1 include: S11: The heavy inert filler particles and the resin component (component A) of the liquid-curing polymer potting compound are mixed for the first time at a mass ratio of (0.8-1.2):1, and stirred until uniform. S12: Add component B according to the specified curing agent component (i.e., component B) addition ratio of the liquid curing polymer potting compound, and mix for a second time. Stir evenly to obtain the filler mixture.
6. The process method according to claim 1 or 5, characterized in that, In step S2, the mass ratio of the standard potting compound to the filler mixture is 1:(2-4).
7. The process method according to claim 1, characterized in that, In step S2, after each layer of adhesive is poured, a static leveling process is performed.
8. The process method according to claim 1, characterized in that, In step S3, the static curing is carried out at room temperature.
9. The process method according to claim 1, characterized in that, The method is applicable to the potting and encapsulation of electronic components in photovoltaic inverters, power modules, or controllers.
10. A potting structure, characterized in that, The product is prepared by any one of the process methods described in claims 1 to 9, comprising a first adhesive layer and a second adhesive layer arranged sequentially from bottom to top, and forming a thermally conductive layer on the surface of the electronic component composed of sedimented and enriched heavy inert filler particles, with no air bubbles inside the colloid.