Lightweight concrete safety energy storage cabinet and preparation method thereof

Abstract

The invention discloses a lightweight concrete safety energy storage cabinet and a preparation method thereof, and the lightweight concrete safety energy storage cabinet is obtained by injecting lightweight concrete into a mold and performing steam curing; the lightweight concrete is prepared from the following raw materials in parts by weight: 20 to 40 parts of cement, 8 to 20 parts of silica fume, 8 to 25 parts of slag powder, 0 to 10 parts of fine sand, 15 to 35 parts of lightweight fine ceramsite sand, 0 to 21 parts of coarse ceramsite sand with the particle size of 5 to 10 mm, 0 to 3 parts of steel fiber, 0 to 1.5 parts of PP fiber, 0.5 to 2.0 parts of polycarboxylic acid type water reducing agent, 0 to 14 parts of hollow glass beads, 0.1 to 0.5 part of release agent and water. Wherein the water-binder ratio is 0.15 to 0.22; the use amounts of the steel fibers and the PP fibers are not 0 at the same time; the light ceramsite sand and the coarse ceramsite sand are subjected to pre-wetting treatment before being used; the fireproof, explosion-proof and heat-insulating material has the characteristics of light weight, safety and impermeability, and has excellent fireproof, explosion-proof and heat-insulating properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage cabinets, and in particular relates to a lightweight concrete safety energy storage cabinet and a preparation method thereof. Background Art

[0002] As the scale of electrochemical energy storage installations continues to climb (globally, new energy storage capacity is expected to reach 74GW in 2024), the safety performance of energy storage cabinets, as the core carrier of battery systems, has become a key factor restricting the development of the industry. There are also many different types of energy storage cabinets.

[0003] Steel-structured energy storage cabinets are relatively traditional, with a thermal conductivity of up to 45W / (m·K). In thermal runaway scenarios with local temperatures exceeding 800°C, thermal bridges can easily form, increasing the rate of heat spread by 300%. Furthermore, lithium battery modules generate electromagnetic interference in the 10-100kHz frequency band (field strength >60dBμV / m). While traditional metal cabinets offer electromagnetic shielding effectiveness (SE >30dB), they suffer from eddy current losses, resulting in a 2-3% loss in energy efficiency.

[0004] Although the sandwich composite wall panel type energy storage cabinet has lightweight characteristics, such as density <1950kg / m 3 However, its fire resistance limit is generally less than 1 hour, which makes it difficult to meet the thermal runaway protection requirements of the battery, and the shielding effectiveness of the cabinet is less than 15dB, and the electromagnetic shielding is insufficient.

[0005] Although concrete-based energy storage cabinets have good fire resistance, existing concrete-based energy storage cabinets are heavy. Combined with the weight of the equipment and batteries, the transportation cost increases by 40% compared to steel structure solutions, and the seismic performance decreases by 30%, limiting their application in areas requiring prefabricated components and hoisting.

[0006] For example, Chinese patent CN118955030A discloses a high-safety lithium battery energy storage cabinet based on high-performance concrete. The cabinet comprises the following raw materials by weight: 17-20.5 parts cement, 1.3-2.4 parts silica fume, 4.3-5.5 parts slag powder, 7.3-8.7 parts fly ash, 52.5-57.5 parts sand, 17.3-31.3 parts gravel, 3.9-7.8 parts steel fiber, 0.1 part PP fiber, 0.9-1.5 parts admixture, and the remainder water. The sand has a particle size of <5 mm, and the gravel has a particle size of 5-20 mm. The battery energy storage cabinet provided in this patent uses 17.3-31.3 parts of crushed stone and 52.5-57.5 parts of medium sand as coarse aggregate and fine aggregate in the concrete material, respectively. The use of both greatly increases the weight of the energy storage cabinet, and the coarse aggregate is the main reason for the increase in internal porosity in the concrete, which is one of the main reasons for the durability failure of concrete. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides a lightweight concrete safety energy storage cabinet and a preparation method thereof, which has the characteristics of being lightweight, safe, and impermeable, and has excellent fireproof, explosion-proof and heat-insulating properties.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides a lightweight concrete safety energy storage cabinet, which is obtained by injecting lightweight concrete into a mold and then performing steam curing.

[0010] The lightweight concrete is composed of the following raw materials in parts by weight: 20-40 parts of cement, 8-20 parts of silica fume, 8-25 parts of slag powder, 0-10 parts of fine sand, 15-35 parts of lightweight fine ceramsite sand, 0-21 parts of coarse ceramsite sand with a particle size of 5-10 mm, 0-3 parts of steel fiber, 0-1.5 parts of PP fiber, 0.5-2.0 parts of polycarboxylic acid water reducer, 0-14 parts of hollow glass microspheres, 0.1-0.5 parts of release agent, and water; the ratio of the weight of the water to the total weight of the cement, silica fume and slag powder is 0.15-0.22:1; the lightweight concrete is a lightweight ultra-high performance concrete (LUHPC) material;

[0011] The amount of the steel fiber and the PP fiber is not 0 at the same time;

[0012] The lightweight fine ceramsite sand and coarse ceramsite sand are pre-moistened before use to play an internal curing role and avoid the occurrence of cement hydration concentration and micro cracks in a low water-cement ratio dense environment.

[0013] Furthermore, the inner wall of the lightweight safety energy storage cabinet is coated with a heat-insulating fire-retardant coating, which further improves the fire resistance of the energy storage cabinet. The heat-insulating fire-retardant coating is a heat-insulating fire-retardant coating containing SiO2 aerosol.

[0014] The cement is 525 cement;

[0015] The silica fume has a SiO2 mass percentage of ≥95% and a 7d activity index of ≥110%;

[0016] The particle size of the fine sand is less than 5 mm.

[0017] The slag powder is S95 grade slag powder.

[0018] The lightweight fine ceramsite sand is shale ceramsite with a particle size of 0-5mm and a bulk density of 700-900kg / m 3 .

[0019] The coarse ceramsite sand is shale ceramsite with a particle size of 5-10 mm and a bulk density of 500-700 kg / m 3 .

[0020] The bulk density of the hollow glass microspheres is 350-400 kg / m 3 .

[0021] The length of the steel fiber is 10 to 15 mm; the length of the PP fiber is 10 to 15 mm. The addition of the fiber can improve the overall toughness of the concrete.

[0022] The release agent is a water-based silicone emulsion release agent, which is used to improve the surface glossiness of lightweight concrete after molding. It can be omitted if there is no requirement for glossiness of the concrete surface.

[0023] The present invention also provides a method for preparing the lightweight concrete safety energy storage cabinet, which comprises the following steps:

[0024] S1: After uniformly mixing water, cement, silica fume, slag powder, hollow glass microspheres, polycarboxylic acid type water reducer and release agent in a twin-shaft forced mixer, fine sand, lightweight fine ceramsite sand, steel fiber and PP fiber are added in sequence and mixed evenly;

[0025] S2: Add coarse ceramsite sand and mix evenly to obtain lightweight concrete;

[0026] S3: Lightweight concrete is poured into the mold and cured for 1-2 days before being removed from the mold. The cabinet is then placed in a steam curing chamber and cured for another 3-5 days. Once the surface is completely dry, the interior is coated with a thermal insulation and fire-retardant coating, resulting in a lightweight concrete safety energy storage cabinet. Steam curing accelerates cement hydration, facilitating faster entry into subsequent processes compared to standard curing or room temperature curing for 28 days, significantly shortening the construction period.

[0027] In step S3, in order to further improve the fire resistance, anti-seepage and explosion-proof performance of the lightweight safety energy storage cabinet, the mold is also equipped with steel bars, and the position and quantity of the steel bars can be set according to requirements.

[0028] The structure of the lightweight concrete safety energy storage cabinet provided by the present invention includes a cabinet and ventilation holes reserved for installation on the side of the cabinet. The inner surface of the cabinet is coated with a thermal insulation and fireproof coating made of SiO2 aerosol. SiO2 has a melting point of approximately 1600°C. The porous structure has a low expansion coefficient at high temperatures and does not decompose or melt at high temperatures. The coating structure remains intact, forming a physical barrier to slow the spread of fire and further improving the fireproof performance of the energy storage cabinet.

[0029] Furthermore, the ventilation device is an air inlet device or an air outlet device, the air inlet device is installed on the side of the cabinet, the air outlet device is installed on the top surface of the cabinet, the air inlet device is connected to the cabinet, and the cabinet is connected to the air outlet device.

[0030] Furthermore, the air outlet device is equipped with a ventilator, and the air outlet of the air outlet device is connected to the ventilator.

[0031] In order to solve the problem of the weight of the safety energy storage cabinet, the present invention uses lightweight fine ceramsite sand with a particle size of 0-5mm and coarse ceramsite sand with a particle size of 5-10mm as aggregates for lightweight concrete in the formula. Based on the theory of improving the homogeneity of materials, the present invention eliminates coarse aggregates. The reduction in aggregate size helps to optimize the interface transition zone of the concrete structure and is beneficial to the improvement of compressive strength. A low water-cement ratio often leads to concentrated cement hydration and the generation of microcracks, which is also a common phenomenon in UHPC materials. To further solve this problem, the present invention pre-wets the lightweight fine ceramsite sand and coarse ceramsite sand before use. During the curing period, the process of the aggregate slowly releasing water can play a role in internal curing, avoiding concentrated cement hydration and causing insufficient water.

[0032] A reduction in density often leads to a rapid decrease in the overall strength of concrete. To further reduce the density of concrete while ensuring material strength, the present invention uses hollow glass microspheres as a density regulator. At the same time, the particle size and dosage of each raw material are precisely controlled to ensure that the use of powder conforms to the principle of closest packing, thereby improving the compressive strength of the safety energy storage cabinet. At the same time, the hollow structure of the hollow glass microspheres also gives them good thermal insulation properties, and the spherical structure can also increase the fluidity and workability of concrete, reduce the friction of concrete during mixing and pouring, and make it easier to construct and operate.

[0033] The present invention adopts the theory of closest particle packing and material homogeneity performance improvement to obtain the required design strength and density of concrete, reduces the porosity inside the concrete, effectively reduces the diffusion of chloride ions in the concrete, improves the anti-permeability grade of lightweight high-strength concrete, and further improves its erosion resistance; PP fiber or steel fiber is added to enhance the splitting (anti-explosion) resistance, compression and bending resistance, and elastic modulus of lightweight concrete, giving it excellent toughness; lightweight ceramsite sand and coarse ceramsite sand are used as porous lightweight aggregates, and their internal curing effect can effectively solve the problem of concentrated cement hydration and microcracks; lightweight fine ceramsite sand and coarse ceramsite sand are used as aggregates, and hollow glass microspheres are used as density regulators. These materials have high internal closed pores and good thermal insulation performance, which can reduce the thermal conductivity of the safety energy storage cabinet to 0.5W / (m·K).

[0034] In order to improve the fire resistance limit of the safety energy storage cabinet, the present invention further coats the inner wall of the lightweight safety energy storage cabinet with a heat-insulating fire-retardant coating. By using the fire-retardant coating, the fire resistance limit of ordinary lightweight aggregate is increased from 1.5-2h to more than 4.5 hours.

[0035] The lightweight concrete used in the safety energy storage cabinets, as provided by this invention, utilizes lightweight aggregates, resulting in a dense surface structure and generally closed internal pores. This reduces the concrete's weight while preserving its compressive strength. This significantly reduces the risk of vapor pressure buildup caused by water evaporation at high temperatures, thus avoiding the cracking problem associated with excessive internal vapor pressure in conventional concrete. The addition of steel or PP fibers creates "microchannels" at high temperatures, helping to release vapor pressure and further enhancing its resistance to cracking.

[0036] At room temperature, the thermal conductivity of UHPC is 1.5-2.0W / (m·K), which is higher than that of ordinary concrete (1.0-1.5W / (m·K)). The present invention reduces the thermal conductivity to 0.5W / (m·K) by adding lightweight aggregate (lightweight fine ceramsite sand, coarse ceramsite sand) and density regulator (such as hollow glass microspheres), thereby meeting the insulation requirements.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] Thermal performance: thermal conductivity is 0.5-0.8W / (m·K), which is 98% lower than that of steel, and the fire resistance limit is 4.5 hours;

[0039] Mechanical properties: According to the design strength grade, the compressive strength can reach 90MPa-130MPa, and the hardened density is 1520-1950kg / m 3 , 19-37% lighter than traditional concrete and 27-43% lighter than UHPC materials;

[0040] Functional enhancement: Through fiber doping, the electromagnetic shielding effectiveness is achieved to 45dB, and the flexural strength is simultaneously increased to 30MPa.

[0041] Thermal safety protection: (1) Multi-scale thermal barrier: The inner surface is coated with nano-SiO2 aerogel coating, and the micron-level closed-pore structure (porosity 30%, pore size <100μm) effectively blocks heat conduction. (2) Lightweight fine aggregate insulation: Lightweight ceramsite sand, coarse ceramsite sand, hollow glass microspheres and other materials are all granular materials with closed surface and porous internal structure, which have the characteristics of lightness, thermal insulation and high strength, significantly reducing the weight of the energy storage cabinet and improving the thermal insulation, fire resistance, pressure resistance and flexural strength of the energy storage cabinet.

[0042] In terms of molding: The lightweight safety energy storage cabinet provided by the present invention is integrally molded and has the advantages of high integration, small footprint, and convenient transportation and installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic structural diagram of the lightweight concrete safety energy storage cabinet in the present invention;

[0044] Figure 2 This is a top-down cross-sectional view of the lightweight concrete safety energy storage cabinet of the present invention. DETAILED DESCRIPTION

[0045] The present invention provides a lightweight concrete safety energy storage cabinet, which is obtained by injecting lightweight concrete into a mold and then steam curing. The lightweight concrete is composed of the following raw materials in parts by weight: 20-40 parts of cement, 8-20 parts of silica fume, 8-25 parts of slag powder, 0-10 parts of fine sand, 15-35 parts of lightweight fine ceramsite sand, 0-21 parts of coarse ceramsite sand with a particle size of 5-10 mm, 0-3 parts of steel fiber, 0-1.5 parts of PP fiber, 0.5-2.0 parts of polycarboxylic acid water reducer, 0-14 parts of hollow glass microspheres, 0.1-0.5 parts of release agent, and water. The ratio of the weight of the water to the total weight of the cement, silica fume, and slag powder is 1:0.15-0.22.

[0046] Wherein, the amount of the steel fiber and the PP fiber is not 0 at the same time;

[0047] The lightweight fine ceramsite sand and the coarse ceramsite sand are pre-wetted before use.

[0048] The inner wall of the lightweight concrete safety energy storage cabinet is coated with a heat-insulating fire-retardant coating; the heat-insulating fire-retardant coating is a heat-insulating fire-retardant coating containing SiO2 aerosol.

[0049] The cement is 52.5 cement;

[0050] The silica fume has a SiO2 mass percentage of ≥95% and a 7d activity index of ≥110%;

[0051] The particle size of the fine sand is less than 5 mm.

[0052] The slag powder is S95 grade slag powder.

[0053] The lightweight fine ceramsite sand is shale ceramsite with a particle size of 0-5mm and a bulk density of 700-900kg / m 3 .

[0054] The coarse ceramsite sand is shale ceramsite with a particle size of 5-10 mm and a bulk density of 500-700 kg / m 3 .

[0055] The bulk density of the hollow glass microspheres is 350-400 kg / m 3 .

[0056] The length of the steel fiber is 10 to 15 mm;

[0057] The length of the PP fiber is 10 to 15 mm.

[0058] The release agent is a water-based silicone emulsion release agent.

[0059] The method for preparing the lightweight concrete safety energy storage cabinet comprises the following steps:

[0060] S1: Mix water, cement, silica fume, slag powder, hollow glass microspheres, release agent and polycarboxylate water reducer evenly in a twin-shaft forced mixer, then add fine sand, lightweight ceramsite sand, steel fiber and PP fiber in sequence and mix evenly;

[0061] S2: Add coarse ceramsite sand and mix evenly to obtain lightweight concrete;

[0062] S3: Pour lightweight concrete into the mold, remove the mold after curing for 1-2 days, and send it into the steam curing room for further curing for 3-5 days. When the surface is completely dry, apply heat-insulating and fire-retardant coating on the inner surface to obtain the energy storage cabinet.

[0063] The present invention is described in detail below with reference to the embodiments.

[0064] The raw material composition and weight of the lightweight concrete in each embodiment, as well as the performance data of the energy storage cabinet are shown in Table 1.

[0065] Table 1

[0066]

[0067] The raw material composition and weight of the concrete in each comparative example, as well as the performance data are shown in Table 2.

[0068] Table 2

[0069]

[0070]

[0071] From the above, it can be seen that in the embodiments 1-5 provided by the present invention, the density of the energy storage cabinet is 1520-1950 kg / m 3 Compared with C80 ordinary concrete (Comparative Example 1), the self-weight is reduced by 19-37%, and compared with UHPC materials (Comparative Example 2), the self-weight is reduced by 27-43%, solving the problems of difficult transportation and lifting of prefabricated components.

[0072] The present invention adopts the theory of close packing of powders, uses cement, silica fume and slag powder as composite cementitious materials, controls the low water-binder ratio to 0.15-0.22 (the general concrete is 0.30-0.35), reduces the internal pore structure, effectively reduces the chloride ion diffusion of concrete, improves the anti-permeability grade of lightweight high-strength concrete, and further improves its anti-erosion ability.

[0073] The present invention adopts the theory of improving the homogeneity of materials and adopts lightweight ceramsite sand, coarse ceramsite sand and density regulator (hollow glass microspheres). These materials have high porosity and good thermal insulation performance. The thermal conductivity coefficient is 0.08-0.3W / (m·K), which is lower than the thermal conductivity coefficient of 1.5-3.0W / (m·K) of siliceous sand. Therefore, the thermal conductivity coefficient of concrete can be reduced to 0.5W / (m·K).

[0074] The present invention increases the fire resistance limit of the energy storage cabinet to 4.5h by using lightweight ceramsite sand, coarse ceramsite sand, hollow glass microspheres and fire-retardant coating, which is a significant improvement compared to the 1.5-2h of ordinary light aggregate.

[0075] The above detailed description of a lightweight concrete safety energy storage cabinet and its preparation method with reference to the embodiments is illustrative rather than restrictive. Several embodiments can be listed according to the limited scope. Therefore, changes and modifications without departing from the overall concept of the present invention should be within the scope of protection of the present invention.

Claims

1. A lightweight concrete safety energy storage cabinet, characterized in that: The lightweight concrete safety energy storage cabinet is obtained by injecting lightweight concrete into a mold and then steam curing it; The lightweight concrete is composed of the following raw materials in parts by weight: 20-40 parts of cement, 8-20 parts of silica fume, 8-25 parts of slag powder, 0-10 parts of fine sand, 15-35 parts of lightweight fine ceramsite sand, 0-21 parts of coarse ceramsite sand with a particle size of 5-10 mm, 0-3 parts of steel fiber, 0-1.5 parts of PP fiber, 0.5-2.0 parts of polycarboxylic acid water reducer, 0-14 parts of hollow glass microspheres, 0.1-0.5 parts of release agent, and water; the ratio of the weight of the water to the total weight of the cement, silica fume and slag powder is 0.15-0.22:1; The amounts of the steel fiber and the PP fiber are not both 0; the lightweight fine ceramsite sand and the coarse ceramsite sand are pre-wetted before use.

2. The lightweight concrete safety energy storage cabinet according to claim 1, characterized in that: The inner wall of the lightweight safety energy storage cabinet is coated with heat-insulating and fire-retardant paint.

3. The lightweight concrete safety energy storage cabinet according to claim 1 or 2, characterized in that: The cement is 525 cement; the SiO2 mass percentage of the silica fume is ≥95%, and the 7d activity index is ≥110%; and the particle size of the fine sand is ≤5mm.

4. The lightweight concrete safety energy storage cabinet according to claim 1 or 2, characterized in that: The slag powder is S95 grade slag powder.

5. The lightweight concrete safety energy storage cabinet according to claim 1 or 2, characterized in that: The bulk density of the lightweight fine ceramsite sand is 700-900 kg / m 3 .

6. The lightweight concrete safety energy storage cabinet according to claim 1 or 2, characterized in that: The coarse ceramsite sand is shale ceramsite with a particle size of 5-10 mm and a bulk density of 500-700 kg / m 3 .

7. The lightweight concrete safety energy storage cabinet according to claim 1 or 2, characterized in that: The bulk density of the hollow glass microspheres is 350-400 kg / m 3 .

8. The lightweight concrete safety energy storage cabinet according to claim 1 or 2, characterized in that: The length of the steel fiber is 10 to 15 mm; the length of the PP fiber is 10 to 15 mm.

9. The lightweight concrete safety energy storage cabinet according to claim 1 or 2, characterized in that: The release agent is a water-based silicone emulsion release agent.

10. A method for preparing a lightweight concrete safety energy storage cabinet according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: S1: After uniformly mixing water, cement, silica fume, slag powder, hollow glass microspheres, polycarboxylic acid type water reducer and release agent in a twin-shaft forced mixer, fine sand, lightweight fine ceramsite sand, steel fiber and PP fiber are added in sequence and mixed evenly; S2: Add coarse ceramsite sand and mix evenly to obtain lightweight concrete; S3: Pour lightweight concrete into the mold, remove the mold after curing for 1-2 days, and send it into the steam curing room for further curing for 3-5 days. When the surface is completely dry, apply heat-insulating and fire-retardant coating on the inner surface to obtain a lightweight concrete safety energy storage cabinet.

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