Electric motor coach with fireproof structure

Abstract

The utility model provides a kind of electric bus with fireproof structure, including battery cabin and passenger cabin, the battery cabin and passenger cabin are isolated by isolation structure;The isolation structure includes metal isolation base material and non-metal isolation base material;For metal isolation base material, its surface is provided with fireproof coating, for non-metal isolation base material, its surface is sequentially provided with heat insulation coating and fireproof coating.The electric bus of this embodiment can control the temperature of passenger cabin in an acceptable range after battery explosion accident, and give passengers enough escape time, greatly improve its driving safety.

Description

Technical Field

[0001] This utility model relates to the field of electric vehicle technology, and in particular to an electric bus with a fireproof structure. Background Technology

[0002] Electric buses are passenger vehicles powered by onboard electricity and equipped with appropriate onboard batteries. Electric buses are increasingly being used due to their advantages, including good power performance, long driving range, long battery life (over two years), and lower cost.

[0003] During the operation of electric buses, the battery may explode under extreme conditions, making it crucial to minimize the harm to passengers in the cabin. Currently, most automakers use fireproof cloth to separate the battery compartment from the passenger cabin to prevent injury from battery explosions. However, fireproof cloth has the following drawbacks: 1. Insufficient high-temperature fire resistance: Although the fireproof cloth meets the Class A requirements of GB 8624-2012 standard in terms of combustion characteristics and has a thermal conductivity of less than 0.04 W / (m·K) at 300℃, it is prone to carbonization and failure when the fire temperature of the battery compartment reaches 800-1100℃. Its ability to block flame and heat transfer is significantly reduced, so the fire resistance time is not long.

[0004] 2. Poor construction adaptability: Fireproof cloth needs to be cut to fit the battery compartment structure, which results in poor fit, inability to fully cover gaps and corners, and easy to fall off. In the event of a fire, a large amount of toxic smoke can easily spread to the passenger cabin through these areas. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings of the prior art and provide an electric bus with a fireproof structure to improve the above-mentioned problems.

[0006] This utility model provides an electric bus with a fireproof structure, including a battery compartment and a passenger compartment, which are isolated by an isolation structure. The isolation structure includes a metal isolation substrate and a non-metal isolation substrate. For the metal isolation substrate, a fireproof coating is provided on its surface. For the non-metal isolation substrate, a heat insulation coating and a fireproof coating are provided on its surface in sequence. The fireproof coating uses an expandable graphite split and nano-silica.

[0007] Preferably, the thickness of the fire-retardant coating is 150-250 μm.

[0008] Preferably, the heat-insulating coating is a heat-insulating paint.

[0009] Preferably, the thickness of the heat-insulating coating is 150-250 μm.

[0010] Preferably, the fire-retardant coating is formed on the surface of the battery compartment.

[0011] Preferably, for the rear battery compartment, a fire-retardant coating is sprayed onto the rear battery compartment at the intermediate coating station; for the front and rear top-mounted battery compartments, a fire-retardant coating is sprayed onto the top-mounted battery compartment at the finishing coating station.

[0012] The electric bus in this embodiment can quickly control the temperature of the passenger cabin to an acceptable range after a battery explosion in the battery compartment, and give passengers sufficient time to escape, greatly improving the driving safety of the electric bus. Attached Figure Description

[0013] Figure 1 A schematic diagram of the structure of an electric bus with a fireproof structure provided in an embodiment of this utility model; Figure 2 It is a temperature-time curve of the unexposed side of a board coated with a fire-retardant coating. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. 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. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely to represent selected embodiments of this utility model.

[0015] Please see Figure 1 This utility model provides an electric bus with a fireproof structure, including a battery compartment 10 and a passenger compartment 20, which are isolated by an isolation structure 30. The isolation structure 30 includes a metal isolation substrate and a non-metal isolation substrate. For the metal isolation substrate, a fireproof coating is provided on its surface, and for the non-metal isolation substrate, a heat insulation coating and a fireproof coating are provided on its surface in sequence.

[0016] In this embodiment, considering factors such as the actual application scenario of electric buses and the probability of fire, and after sourcing and testing fire-retardant coatings on the market according to technical requirements, a commercially available fire-retardant coating mainly containing expandable graphite fractions and nano-silica was ultimately selected, such as the fire-retardant coating YL8129 from Xiamen Youlian Technology Co., Ltd. This type of fire-retardant coating has dual expansion characteristics of physical and chemical expansion, and the expanded carbon layer is extremely stable at high temperatures, exhibiting excellent heat insulation performance.

[0017] In this embodiment, for the metal insulating substrate between the battery compartment and the passenger cabin, fireproofing is achieved by coating the surface of the metal insulating substrate with a fire-retardant coating.

[0018] The specific construction method is as follows: Mix the fire-retardant coating and hardener evenly, and let it stand for 10 minutes to defoam.

[0019] The mixing ratio of fire-retardant coating and curing agent can be selected as 9:1.

[0020] A wet film with a thickness of 200-300μm was obtained by single-pass spraying using a high-pressure spray gun (nozzle diameter 1.55mm, pressure 0.5MPa). Curing process: Curing in an 80℃ oven for 35 minutes to form a fire-retardant coating with a dry film thickness of 150-250μm.

[0021] In this embodiment, for the non-metallic insulating substrate between the battery compartment and the passenger cabin, fire prevention is achieved by coating the surface of the non-metallic insulating substrate with a heat-insulating coating and a fire-retardant coating.

[0022] The specific construction method is as follows: First, apply a heat-insulating paint as a base. After 24 hours of complete drying, a heat-insulating coating with a thickness of 150-250μm will be formed.

[0023] The heat-insulating primer can also be selected from the heat-insulating primer of Xiamen Youlian Technology Co., Ltd., model YL8115.

[0024] Next, take the fireproof coating, mix the main material and hardener evenly according to the ratio, and let it stand for 10 minutes to defoam; use a high-pressure spray gun (nozzle diameter 1.55mm, pressure 0.5MPa) to spray in one pass, with a wet film thickness of 200-300μm; curing treatment: cure in an 80℃ oven for 35 minutes to form a dense coating with a dry film thickness of 200μm.

[0025] It should be noted that the mixing ratio of the fire-retardant coating and the curing agent, as well as the drying temperature and time settings for the fire-retardant coating, are all derived from the product instructions of Xiamen Youlian Technology Co., Ltd., and do not involve any improvement to the material formula or process.

[0026] In addition, the fire-retardant coating also needs to be formed on the surface of the battery compartment 10.

[0027] In this embodiment, for a typical electric bus, the battery compartment can be divided into a rear battery compartment and front / rear roof-mounted battery compartments, depending on its design location. Different construction processes are required for battery compartments in different locations, including: Application method for fire-retardant coating on the rear battery compartment: Mix the fire retardant coating and hardener evenly, and let it stand for 10 minutes to defoam. After spraying the rear battery compartment at the intermediate coating station, dry it at 80℃ for 30-40 minutes. Finally, check for any missed spraying, whether the thickness meets the requirements, and whether the appearance is uniform.

[0028] Application method for fire-retardant coating of front and rear top-mounted battery compartments: Mix the fire retardant coating and hardener evenly, and let it stand for 10 minutes to defoam. After the top battery compartment is coated at the finishing stage of the painting process, it is cured at room temperature for 24 hours. Finally, the coating is checked to see if there are any missed spots, whether the thickness meets the requirements, and whether the appearance is uniform.

[0029] In summary, compared with the prior art, this application has at least the following innovations: 1. This utility model designs different fireproof structures for materials with varying high-temperature resistance. For the high-temperature resistant metal insulation substrate between the battery compartment and the passenger cabin, a fireproof coating is directly constructed. For the non-high-temperature resistant non-metallic insulation substrate between the battery compartment and the passenger cabin, a double-layer structure of heat-insulating coating + fireproof coating is constructed. This double-layer structure prevents high-temperature airflow and toxic fumes from bypassing the gaps between the fireproof cloth and the sealing plate, thus avoiding deformation and melting of the non-metallic plate and the spread of smoke into the passenger cabin.

[0030] 2. Traditional fireproof cloth simply provides physical insulation between the battery compartment and the passenger cabin. If a fire occurs in the battery compartment, the temperature rises rapidly within a short time. Under physical impact and high temperature, the fireproof cloth separates and detaches from the sealing plate, resulting in a significant decrease in its actual fireproof performance. The fireproof coating constructed in this embodiment of the invention, in the event of a fire, achieves a three-stage response as the temperature rises: "gas flame retardancy → carbon layer expansion → skeleton stabilization." When the temperature is ≤200℃, it releases inert gas to dilute the concentration of combustible gases; when the temperature is 200~400℃, it expands to form a porous carbon layer, increasing its thickness to more than 25 times that of the original coating; when the temperature is ≥400℃, the graphite carbon layer and nanofillers synergistically form a high-temperature stable skeleton. This process is completed within 2 minutes, achieving flame retardancy and high-temperature isolation, promptly protecting the sealing plate between the battery compartment and the passenger vehicle, and the gaps between the sealing plates, preventing burn-through of the sealing plate and harm to passenger personnel from flames, high temperatures, and toxic fumes.

[0031] 3. The application of conventional fire-retardant coatings on electric buses primarily targets the battery pack casing, and the application method involves multiple coating layers. This embodiment of the invention selects a fire-retardant coating mainly composed of expandable graphite fractions and nano-silica, effectively ensuring stable and reliable fire-retardant performance even at ultra-thin thicknesses. Therefore, a single-layer spray application is sufficient to meet fire-retardant performance requirements, and it matches the bus painting process rhythm.

[0032] 4. Currently, the technical requirements for fire-resistant materials in China, Europe, and the United States only include requirements for combustion characteristics and thermal conductivity. For example, China's GB 38032-2020 "Safety Requirements for Electric Buses" stipulates that flame-retardant and heat-insulating materials should be used between the rechargeable energy storage system (or installation compartment) and the passenger cabin. The flame-retardant and heat-insulating performance test between the rechargeable energy storage system (or installation compartment) and the passenger cabin should be conducted according to the test method specified in 5.2.2. The combustion characteristics of the flame-retardant and heat-insulating materials should meet the Class A requirements specified in GB 8624-2012, and the thermal conductivity at 300℃ should not exceed 0.04 W / (m·K). The EU only requires fire-resistant materials to meet the ECE R118 combustion characteristics. Due to the special nature of fire-resistant materials used in electric buses, in an emergency situation where the battery catches fire, the fire-resistant materials not only need to be non-combustible, but also need to have a certain fire resistance time to prevent high temperatures, flames, and toxic fumes from spreading to the passenger cabin, giving passengers sufficient time to escape. Currently, there is no standard for fire-resistant materials used in electric buses that specifies the fire resistance time.

[0033] The ultimate goal of this fireproof structure is to improve the fire resistance time of fireproof materials in electric buses, so that passengers are not harmed by high temperatures, flames, and toxic fumes during a fire, and to give passengers sufficient time to escape.

[0034] The following specific experiments will illustrate the fire resistance effect of this embodiment.

[0035] Test setup: Propane flame torch (flame temperature approximately 1100℃); Temperature measurement point: thermocouples attached to the center of both sides of the coating; A 30-minute fire resistance test was conducted using the aforementioned testing equipment.

[0036] Test results are as follows Figure 2 As shown: Temperature curve of the unexposed side: 0~15 seconds: temperature rises from 34℃ to a peak of 178℃ (coating fully expands); 120 seconds: temperature drops to 89℃; 1800 seconds (30 minutes): temperature stabilizes at 86±3℃; fire resistance time ≥30 minutes).

[0037] As can be seen, the fireproof structure of this embodiment can quickly control the temperature of the cabin within an acceptable range after a battery explosion, and give passengers sufficient time to escape (30 minutes).

[0038] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible variations and modifications to the technical solutions of the present invention using the disclosed methods and techniques without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall fall within the protection scope of the present invention. The above description is merely a preferred embodiment of the present invention, and all equivalent variations and alterations made within the scope of the claims of the present invention shall be covered by the present invention.

Claims

1. An electric bus with a fire-resistant structure, comprising a battery compartment and a passenger compartment, wherein the battery compartment and the passenger compartment are isolated by an isolation structure; characterized in that, The isolation structure includes a metal isolation substrate and a non-metal isolation substrate; for the metal isolation substrate, a fireproof coating is provided on its surface, and for the non-metal isolation substrate, a heat insulation coating and a fireproof coating are provided on its surface in sequence; the fireproof coating uses expandable graphite split and nano-silica as the fireproof coating.

2. The electric bus with a fireproof structure according to claim 1, characterized in that, The thickness of the fire-retardant coating is 150-250 μm.

3. The electric bus with a fireproof structure according to claim 1, characterized in that, The heat-insulating coating is a heat-insulating paint.

4. The electric bus with a fire-resistant structure according to claim 1, characterized in that, The thickness of the heat insulation coating is 150-250 μm.

5. The electric bus with a fire-resistant structure according to claim 1, characterized in that, The fire-retardant coating is formed on the surface of the battery compartment.

6. The electric bus with a fire-resistant structure according to claim 5, characterized in that, For the rear battery compartment, a fire-retardant coating is sprayed onto the rear battery compartment at the intermediate coating station; for the front and rear top-mounted battery compartments, a fire-retardant coating is sprayed onto the top-mounted battery compartment at the finishing coating station.

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