Battery pack box body capable of preventing leakage of cooling liquid and vehicle

Abstract

The invention belongs to the technical field of vehicles, and discloses a battery pack box body capable of preventing coolant leakage and a vehicle, the battery pack box body comprises a battery box frame body, an integrated liquid cooling plate and a bottom protection plate, the integrated liquid cooling plate is located between the battery box frame body and the bottom protection plate, and the integrated liquid cooling plate is provided with at least one liquid discharge hole. The liquid discharging hole is communicated with an interlayer area between the integrated liquid cooling plate and the bottom protection plate, and a soluble breathable film and a liquid discharging unit used for preventing the soluble breathable film from being dissolved in advance are arranged at the liquid discharging hole. The liquid discharging function can be automatically started when the cooling liquid leaks, external impurities can be effectively prevented from entering, meanwhile, the problems of detection and differential pressure balance of the sealed space at the bottom of the battery pack are solved, and therefore the safety performance of the battery pack is comprehensively improved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a battery pack case, a high-voltage distribution box and a vehicle capable of preventing coolant leakage. Background Art

[0002] With the rapid development of new energy vehicles, the safety of power battery packs has received increasing attention. In the battery pack cooling system, liquid cooling solutions are widely used due to their high heat dissipation efficiency. However, there is a risk of leakage in the liquid cooling system, which may cause serious safety hazards once leakage occurs.

[0003] At present, there are two main solutions for battery pack liquid leakage in the industry: one is to use autonomous valve opening technology to trigger the opening of the drain valve by detecting the increase in the weight of the leaked liquid or utilizing the water absorption and expansion characteristics of the expansion body. Although this solution can achieve automatic drainage, there is a potential risk that external impurities may enter the battery pack through the drain valve. The second is to set a drain valve on the side panel of the battery pack and open and close it manually or electronically. However, the manual operation method poses a risk to personnel safety, and the electronic control method may cause valve opening delays due to judgment conditions and control logic problems, and is prone to short circuits, control failures and other faults in the event of leakage.

[0004] Especially in the design where the liquid cooling plate is located at the bottom of the battery pack, the existing technology adopts a completely sealed space solution to prevent external corrosion of the liquid cooling plate, which makes it difficult to test the sealing performance of the battery pack after assembly, and it is also impossible to balance the internal and external pressure difference. In addition, when a large amount of liquid accumulates inside the battery pack, it may cause serious safety accidents such as battery short circuit, fire or even explosion.

[0005] Therefore, it is urgent to develop a new drainage solution to solve the above technical problems. Summary of the invention

[0006] In order to solve or partially solve the problems existing in the related art, the purpose of the present invention is to provide a battery pack box and a vehicle that can prevent coolant leakage. The battery pack can automatically start the drainage function when the coolant leaks, and can effectively prevent the entry of external impurities. At the same time, it solves the detection and pressure difference balance problems of the sealed space at the bottom of the battery pack, thereby comprehensively improving the safety performance of the battery pack.

[0007] To achieve the above-mentioned purpose, the present invention provides a battery pack case capable of preventing coolant leakage, comprising a battery box frame, an integrated liquid cooling plate and a bottom guard plate, wherein the integrated liquid cooling plate is located between the battery box frame and the bottom guard plate, and at least one drainage hole is provided on the integrated liquid cooling plate, and the characteristic is that the drainage hole is connected to the interlayer area between the integrated liquid cooling plate and the bottom guard plate, and a soluble breathable membrane and a drainage unit for preventing the soluble breathable membrane from dissolving prematurely are provided at the drainage hole.

[0008] In some embodiments of the present invention, the drainage unit includes a moisture-proof cover, and the moisture-proof cover is provided with a mounting portion for mounting a hygroscopic material and a connecting portion for connecting an integrated liquid cooling plate.

[0009] In some embodiments of the present invention, a hygroscopic material is disposed in the mounting portion.

[0010] In some embodiments of the present invention, the hygroscopic material comprises an outer breathable film of the hygroscopic material and a hygroscopic material body, and the outer breathable film of the hygroscopic material covers the hygroscopic material body.

[0011] In some embodiments of the present invention, the outer peripheral surface of the mounting portion is provided with penetrating moisture-proof cover vertical surface moisture absorption holes, and the bottom surface of the mounting portion is provided with penetrating moisture-proof cover middle portion moisture absorption holes.

[0012] In some embodiments of the present invention, the connecting portion includes a coaxially arranged annular first feature and a disc-shaped connecting second feature, and the first feature is provided with a plurality of moisture-proof cover water holes arranged at intervals along the circumference and penetrating radially.

[0013] In some embodiments of the present invention, the soluble breathable membrane is fixed between the second feature and the upper end surface of the integrated liquid cooling plate.

[0014] In some embodiments of the present invention, the projection shape of the soluble breathable membrane in a first plane perpendicular to the center line thereof is larger than the projection shape of the drainage hole in the first plane perpendicular to the center line thereof.

[0015] In some embodiments of the present invention, water-absorbing foam is provided between the integrated liquid cooling plate and the bottom guard plate.

[0016] The invention also discloses a vehicle, which comprises a high-voltage distribution box.

[0017] The invention has the following advantages: the overall structure of the invention is small and simple, the number of parts is small, the assembly is convenient, and the production cost is low. This efficient and economical design not only solves the problem of automatic discharge of liquid leakage in the battery pack, but also realizes multiple functions such as moisture-proof, breathable, and pressure difference balance, providing a reliable and cost-effective technical solution for the safe operation of the power battery pack of new energy vehicles.

[0018] First, the present invention sets the drainage hole on the bottom liquid cooling plate, taking advantage of its location at the lowest point in the box. Only a small amount of leaked liquid can trigger the dissolution of the soluble breathable membrane to achieve automatic drainage. This design does not require external auxiliary means such as manual or electronic control, and can quickly drain the liquid to the interlayer area between the liquid cooling plate and the bottom guard plate, effectively reducing the accumulation height of the leaked liquid and significantly improving the reliability and safety of the battery.

[0019] Secondly, unlike the traditional solution of directly discharging the liquid to the outside of the battery pack, the present invention introduces the liquid into the closed interlayer area between the liquid cooling plate and the bottom guard plate. Since this area is isolated from the external environment, the risk of external impurities entering the battery pack during the discharge process is completely avoided. This design achieves reliable protection function through a simple structure, reflecting a high cost-effectiveness.

[0020] Thirdly, by setting a combined structure of a moisture-proof cover and a moisture-absorbing material in the drainage unit, and coordinating the moisture-absorbing holes on the vertical surface of the moisture-proof cover and the design of the moisture-absorbing holes in the middle, it not only ensures that the soluble breathable membrane will not dissolve prematurely due to environmental humidity, but also achieves effective ventilation and pressure difference balance in the interlayer area. In particular, this design makes it easy to perform airtightness testing on the sealing area between the bottom guard plate and the liquid cooling plate after the battery pack is assembled, effectively monitoring the sealing performance.

[0021] In addition, the hygroscopic material body is covered with an external breathable membrane, and multiple circumferentially spaced moisture-proof cover holes are set at the connection part to further enhance the system's moisture-proof effect and drainage capacity. The optimized size design of the soluble breathable membrane effectively prevents contamination by debris after the membrane is dissolved. By adding absorbent foam between the integrated liquid cooling plate and the bottom guard plate, an additional protective layer is provided to buffer and absorb in the event of leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments disclosed in the present invention, the drawings of the embodiments will be briefly introduced below. These drawings are only used for illustrative purposes and are not intended to limit the protection scope of the present invention.

[0023] Figure 1 is a schematic diagram of a battery pack box capable of preventing coolant leakage according to the present invention;

[0024] Figure 2 yes Figure 1 A local enlarged view;

[0025] Figure 3 It is a schematic diagram of a bottom liquid cooling plate of a battery pack box capable of preventing leakage of coolant according to the present invention;

[0026] Figure 4 yes Figure 3 D partial magnification attempt;

[0027] Figure 5 It is a schematic diagram of a drain device for a battery pack box capable of preventing coolant leakage according to the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Example 1

[0030] like Figure 1-5 As shown, the present invention provides a battery pack box capable of preventing coolant leakage, which is mainly composed of a battery box frame 1, an integrated liquid cooling plate 2, a water-absorbing foam 3 and a bottom guard plate 4. Among them, the integrated liquid cooling plate 2 is located between the battery box frame 1 and the bottom guard plate 4, forming a three-layer structural design.

[0031] In this embodiment, a plurality of drainage holes 21 are designed on the integrated liquid cooling plate 2. The specific locations of these drainage holes are selected in the BDU (battery distribution unit) area, that is, the lowest point in the battery pack box. The number of drainage holes can be flexibly adjusted according to the actual drainage needs to ensure sufficient drainage capacity. These drainage holes 21 are connected to the interlayer area formed between the integrated liquid cooling plate 2 and the bottom guard plate 4 to form a liquid discharge channel.

[0032] In order to realize the automatic drainage function, a soluble breathable membrane 54 is provided at each drainage hole 21. The breathable membrane is made of special materials and has a single-sided adhesive design, which can be directly adhered around the drainage hole 21. One side of the breathable membrane 54 is hydrophobic, which can effectively prevent the attachment and penetration of liquid water; the other side has a soluble property and will automatically dissolve when it comes into contact with water or a specific solvent. The drainage hole 21 adopts a design of multiple small hole arrays, which not only facilitates the passage of liquid, but also increases the support stiffness of the breathable membrane.

[0033] In order to prevent the soluble breathable membrane 54 from dissolving prematurely due to excessive humidity, a special drainage unit is designed. The core component of the unit is the moisture-proof cover 52, which can be made of metal or engineering plastic. The moisture-proof cover 52 can be connected to the liquid cooling plate 2 in a variety of ways, including threaded connection, welding or snap connection. A compressible gasket 53 is provided between the moisture-proof cover 52 and the breathable membrane 54 to compact and fix the breathable membrane to prevent it from bulging or displacement.

[0034] The structure of the moisture-proof cover 52 is divided into two main functional areas: the installation part and the connection part. The installation part is specifically used to accommodate the moisture-absorbing material 51. The moisture-absorbing holes 521 on the vertical surface of the moisture-proof cover and the moisture-absorbing holes 522 in the middle of the moisture-proof cover are respectively arranged on its outer peripheral surface and bottom surface to form an all-round moisture-absorbing channel. The moisture-absorbing material 51 adopts a double-layer structure design, including an outer layer of the moisture-absorbing material outer breathable membrane 511 and an inner layer of the moisture-absorbing material body 512. The moisture-absorbing material body 512 is completely covered by the outer breathable membrane 511 to improve the moisture absorption effect.

[0035] The connection part adopts a coaxial design, including an outer annular first feature and an inner disc-shaped second feature. A plurality of radially penetrating moisture-proof cover water holes 523 are evenly arranged on the first feature, and these water holes are spaced along the circumference. The soluble breathable membrane 54 is fixed between the second feature and the upper end surface of the integrated liquid cooling plate 2. To ensure a good sealing effect, the size of the breathable membrane 54 is optimized, and its projected area in a plane perpendicular to the center line is larger than the projected area of ​​the drainage hole 21.

[0036] Water-absorbing foam 3 is arranged in the interlayer space between the integrated liquid cooling plate 2 and the bottom guard plate 4. According to the maximum possible leakage of the battery pack, water-absorbing foam with stronger water-absorbing ability can be selected to replace the ordinary foam to improve the liquid storage capacity of the interlayer area, and at the same time, it can effectively prevent the liquid from flowing back into the battery compartment when the battery pack is tilted.

[0037] This design not only solves the problem of liquid leakage, but also has important process value. During the battery pack production process, the installation sealing reliability of the bottom guard plate can be tested through the drainage hole 21. During the driving process of the vehicle, the drainage hole 21 can also help the sealing area to achieve automatic balance of the internal and external pressure difference, ensuring the long-term reliable operation of the system.

[0038] The battery pack box of the present invention can be applied to various types of new energy vehicles, and is particularly suitable for vehicles equipped with high-voltage distribution boxes, providing reliable safety protection for the power battery system.

[0039] Example 2

[0040] This embodiment takes a heavy-duty electric truck power battery pack with a rated power of 500kW as an example to illustrate the specific application scenarios of the present invention in detail.

[0041] The heavy truck adopts a double-layer protection structure of "box + tray". The total capacity of the battery pack is 425kWh, consisting of two large-capacity battery packs connected in parallel. Each battery pack is equipped with 252 square cells and uses a liquid cooling system for thermal management. The size of a single battery pack is 2200mm×1100mm×350mm, and the coolant volume is about 15L.

[0042] In this application scenario, the battery box frame 1 is made of aluminum alloy material, which is realized by extrusion molding process, and has a wall thickness of 4mm. The integrated liquid cooling plate 2 is also made of aluminum alloy material, adopts a multi-channel flow channel design, and has a working pressure of 0.3MPa. A total of 4 drainage holes 21 are arranged on the liquid cooling plate 2, each with a diameter of 12mm, which are located at the four corners of the BDU area, that is, the lowest point inside the box. This layout ensures that in the extreme case where the vehicle is tilted 15 degrees front and back or 12 degrees left and right, at least one drainage hole can still be kept at the lowest point.

[0043] The soluble breathable membrane 54 is made of a special PVA (polyvinyl alcohol) material with a thickness of 0.2mm. It can withstand a pressure of 0.5MPa without breaking at room temperature. Its hydrophobic surface has been specially treated to remain undegraded for 72 hours in an environment with a relative humidity of 95%; and when it comes into direct contact with the coolant, it can completely dissolve within 30 seconds to form a channel of no less than 8mm. The diameter of the breathable membrane 54 is 20mm, which is larger than the diameter of the drainage hole 21, and the edge is fixed to the liquid cooling plate 2 by epoxy resin adhesive.

[0044] The moisture-proof cover 52 is injection molded with PA66 engineering plastic, with a diameter of 30mm and a height of 25mm. The upper mounting cavity is filled with a silica gel hygroscopic material 51 with a diameter of 25mm and a height of 15mm. The hygroscopic material is coated with a PTFE breathable membrane 511 with a pore size of 0.1μm, which can ensure air permeability and prevent dust from entering. Eight vertical hygroscopic holes 521 with a diameter of 2mm are set on the outer peripheral surface of the moisture-proof cover 52, and four middle hygroscopic holes 522 with a diameter of 3mm are set on the bottom surface. Twelve water holes 523 with a diameter of 3mm are evenly distributed on the annular first feature of the connecting part.

[0045] A 10 mm thick polyurethane water-absorbing foam 3 is filled between the integrated liquid cooling plate 2 and the bottom guard plate 4. Its water absorption rate reaches 20 times of its own weight and can quickly absorb up to 10L of coolant in the event of leakage. The bottom guard plate 4 is made of 2 mm thick cold-rolled steel plate with an anti-corrosion surface treatment.

[0046] In actual use, when a leak occurs in the cooling system inside the battery pack, the system works as follows:

[0047] 1. When the leaked liquid contacts the soluble breathable membrane 54, the breathable membrane dissolves within 30 seconds to form a drainage channel;

[0048] 2. The liquid flows into the interlayer area between the liquid cooling plate 2 and the bottom guard plate 4 through the drainage hole 21 and is quickly absorbed by the water-absorbing foam 3;

[0049] 3. The BMS (battery management system) detects abnormal coolant level, and the system issues an alarm and reduces power;

[0050] 4. The vehicle can continue to drive 100 kilometers in reduced power mode to the nearest maintenance point for inspection.

[0051] Avoid the potential safety hazard caused by sudden vehicle stopping.

[0052] During the vehicle assembly process, the sealing of the bottom guard plate 4 is tested through the drainage hole 21: 0.2MPa nitrogen is injected into the interlayer area, and the pressure is maintained for 10 minutes. If the pressure drop does not exceed 0.02MPa, it is qualified. During normal vehicle driving, when the vehicle quickly climbs from sea level to the 3,000-meter plateau area, the moisture absorption holes 521 on the vertical surface of the moisture-proof cover and the moisture absorption holes 522 in the middle can achieve automatic balance between the interlayer area and the external atmospheric pressure, avoiding sealing failure caused by deformation of the sealing ring.

[0053] This system was tested on 100 test vehicles of a heavy truck manufacturer for a year. During this period, three coolant leakage accidents occurred, all of which were handled by the system in a timely manner. No water ingress or leakage accidents occurred in the battery pack, which fully verified the reliability of the anti-leakage system. In addition, the overall cost of the system is only 40% of the traditional solenoid valve drainage solution, which has a significant cost advantage.

[0054] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A battery pack box capable of preventing coolant leakage, comprising a battery box frame (1), an integrated liquid cooling plate (2) and a bottom guard plate (4), wherein the integrated liquid cooling plate (2) is located between the battery box frame (1) and the bottom guard plate (4), and at least one drainage hole (21) is provided on the integrated liquid cooling plate (2), characterized in that: The drainage hole (21) is connected to the interlayer area between the integrated liquid cooling plate (2) and the bottom guard plate (4), and a soluble breathable membrane (54) and a drainage unit for preventing the soluble breathable membrane (54) from dissolving prematurely are arranged at the drainage hole (21).

2. The battery pack box capable of preventing coolant leakage according to claim 1, characterized in that: The drainage unit comprises a moisture-proof cover (52), and the moisture-proof cover (52) is provided with a mounting portion for mounting a hygroscopic material (51) and a connecting portion for connecting to an integrated liquid cooling plate (2).

3. The battery pack box capable of preventing coolant leakage according to claim 2, characterized in that: A moisture absorbing material (51) is arranged in the installation portion.

4. The battery pack box capable of preventing coolant leakage according to claim 3, characterized in that: The hygroscopic material (51) comprises a hygroscopic material outer breathable film (511) and a hygroscopic material body (512), wherein the hygroscopic material outer breathable film (511) covers the hygroscopic material body (512).

5. The battery pack box capable of preventing coolant leakage according to claim 3, characterized in that: The outer peripheral surface of the installation portion is provided with a penetrating moisture-proof cover vertical surface moisture absorption hole (521), and the bottom surface of the installation portion is provided with a penetrating moisture-proof cover middle portion moisture absorption hole (522).

6. The battery pack box capable of preventing coolant leakage according to claim 2, characterized in that: The connecting portion comprises a coaxially arranged annular first feature and a disc-shaped connecting second feature, and the first feature is provided with a plurality of moisture-proof cover water holes (523) which are arranged at intervals along its circumference and penetrate radially.

7. The battery pack box capable of preventing coolant leakage according to claim 6, characterized in that: The soluble breathable membrane (54) is fixed between the second feature and the upper end surface of the integrated liquid cooling plate (2).

8. The battery pack box capable of preventing coolant leakage according to claim 1, characterized in that: The projection shape of the soluble breathable membrane (54) in a first plane perpendicular to its center line is larger than the projection shape of the drainage hole (21) in the first plane perpendicular to its center line.

9. The battery pack box capable of preventing coolant leakage according to claim 1, characterized in that: Water-absorbing foam (3) is arranged between the integrated liquid cooling plate (2) and the bottom guard plate (4).

10. A vehicle, characterized in that: Including the high-voltage distribution box as described in claim 9.

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