Drain device for excluding leaked coolant of power battery pack

Abstract

This invention discloses a draining device for draining leaking coolant from a power battery pack. It includes a housing fixedly connected to the power battery pack casing, with an open-end cavity formed within the housing. A liquid-absorbing expansion body and a draining unit are sequentially arranged along the axis of the cavity. The power battery pack casing communicates with the liquid-absorbing expansion body and the draining unit. The housing has a drain port that opens or closes via the draining unit. The liquid-absorbing expansion body absorbs liquid and expands to push the draining unit to open the drain port, thereby connecting the power battery pack casing, the draining unit, and the drain port to form a drainage channel. Through this method, the draining device for draining leaking coolant from a power battery pack can quickly drain coolant accumulated in low-lying areas of the power battery pack when leakage occurs, thus preventing more serious battery pack failures, short circuits, or thermal runaway, and protecting the safety of occupants and property.

Description

Technical Field

[0001] This invention relates to the field of drain valves, and in particular to a drain device for draining coolant leaking from a power battery pack. Background Technology

[0002] The purpose of cooling systems in automotive lithium-ion battery packs is to maintain the optimal operating temperature of the lithium-ion batteries by cooling or heating them, thereby improving their operating efficiency and extending their lifespan. Currently, the thermal management of automotive lithium-ion battery pack systems can be mainly divided into four categories: natural cooling, air cooling, liquid cooling, and direct cooling.

[0003] Liquid cooling uses a coolant (such as ethylene glycol) as the heat exchange medium. It typically involves multiple different heat exchange loops; for example, the Chevrolet Volt has a radiator loop, an air conditioning loop, and a PTC loop. The battery management system adjusts and switches these loops according to the thermal management strategy.

[0004] However, under high-temperature oxidation, the hydroxyl groups of ethylene glycol in the coolant will become acidified. When operating in cycles at 80°C and -90°C for a long time, ethylene glycol will be oxidized into glycolic acid, and then into oxalic acid. Oxalic acid and ethylene glycol oxalic acid will corrode the equipment and the liquid cooling pipes. In particular, the liquid cooling pipes are made of aluminum foil or copper foil welded together. The weld seams or surface defects of the liquid cooling pipes are easily corroded and leaks will occur. If the leaked ethylene glycol coolant cannot be discharged from the battery pack in time, it will lead to battery pack failure, short circuit or thermal runaway. However, it is not possible to directly open a leak hole on the battery pack, because the battery pack must be kept dry inside under normal operating conditions to prevent condensation and fogging. Summary of the Invention

[0005] The main technical problem solved by this invention is to provide a draining device for draining coolant leaking from a power battery pack. This device can quickly drain coolant accumulated in low-lying areas of the power battery pack when a leak occurs, thereby preventing larger battery pack failures, short circuits, or thermal runaway, and thus protecting the safety of occupants and citizens' property.

[0006] To solve the above-mentioned technical problems, the present invention provides a draining device for draining coolant leaking from a power battery pack, comprising a housing fixedly connected to the power battery pack housing, an inner cavity with one end open within the housing, a liquid-absorbing expansion body and a draining unit sequentially arranged along the axis of the inner cavity, the power battery pack housing communicating with the liquid-absorbing expansion body and the draining unit, and a draining port on the housing that is opened or closed by the draining unit, the liquid-absorbing expansion body absorbing liquid and expanding to push the draining unit to open the draining port, thereby connecting the power battery pack housing, the draining unit and the draining port to form a drainage channel.

[0007] In a preferred embodiment of the present invention, the power battery pack housing and the outer shell have a first channel and a second channel, the first channel connecting the liquid-absorbing expansion body to the power battery pack housing, and the second channel connecting the liquid-draining unit to the power battery pack housing.

[0008] In a preferred embodiment of the present invention, the drain unit is a valve stem dynamically sealed in the inner cavity. The middle part of the valve stem is separated from the outer shell and forms a drain channel. The valve stem moves relative to the drain port to open or close the drain port. The coolant in the power battery pack housing is absorbed by the liquid absorption expansion body through the first channel. After the liquid absorption expansion body expands, it pushes the valve stem to the right, thereby causing the coolant to drain through the second channel, the drain channel and the drain port.

[0009] In a preferred embodiment of the present invention, the right end of the valve stem blocks the drain port, and the valve stem is moved to the right to separate the right end of the valve stem from the drain port, thereby opening the drain port.

[0010] In a preferred embodiment of the present invention, the valve stem has an I-shaped cross-section, and the two ends of the valve stem are dynamically sealed to the inner wall of the outer casing through sealing rings.

[0011] In a preferred embodiment of the present invention, the draining unit is a ball valve core with a drain hole. The gear below the central shaft of the ball valve core is connected to the rack rod. The rack rod is in contact with the liquid-absorbing expansion body. The coolant of the power battery pack housing is absorbed by the liquid-absorbing expansion body through the first channel. After the liquid-absorbing expansion body expands, it pushes the rack rod to drive the ball valve core to rotate, thereby causing the coolant to drain through the second channel, the drain hole and the drain outlet.

[0012] In a preferred embodiment of the present invention, an adjusting screw is threadedly connected to the opening of the inner cavity. The adjusting screw presses the liquid-absorbing expansion body onto the drainage unit and closes the opening of the inner cavity.

[0013] In a preferred embodiment of the present invention, a reset spring is provided at the right end of the inner cavity, the reset spring being pressed between the right end face of the drain unit and the inner wall of the outer shell, and a balance air port is also provided at the right end of the inner cavity.

[0014] In a preferred embodiment of the present invention, a sealing gasket is provided between the power battery pack housing and the outer shell.

[0015] In a preferred embodiment of the present invention, the liquid-absorbing swelling body is a filler of a polymeric resin material that absorbs ethylene glycol coolant. The filler of the polymeric resin material is an expansion rod or expansion pad made of one or more of the following: phosphazene onium ionomer, docosahexamethacrylate and glycidyl methacrylate copolymer monomer, water-absorbing resin, and water-stopping and water-absorbing swelling rubber.

[0016] The beneficial effects of the present invention are as follows: The present invention provides a draining device for draining coolant leaking from the power battery pack. A liquid-absorbing expansion body that expands upon absorbing coolant is used to open the draining unit. The draining unit discharges the leaking coolant from the power battery pack housing through the drain hole, preventing coolant from accumulating in low-lying areas inside the power battery pack and reducing the risk of short circuits within the battery pack.

[0017] This invention provides a draining device for preventing coolant leakage from a power battery pack. It uses a liquid-absorbing expansion body that expands upon absorbing coolant to open the draining unit. When there is no coolant leakage from the power battery pack, the draining unit isolates the inside of the battery pack from the outside air, ensuring that the inside of the battery pack is not affected by the external environment.

[0018] This invention relates to a draining device for preventing coolant leakage from a power battery pack. The draining unit is designed with a valve stem or ball valve core, which is simple in structure, easy to install, and has good performance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0020] Figure 1 This is a schematic diagram of a preferred embodiment of the coolant drainage device for eliminating leakage from the power battery pack according to the present invention;

[0021] Figure 2 This is a schematic diagram of the draining state of the draining device for eliminating coolant leakage from the power battery pack according to the present invention;

[0022] Figure 3 This is a schematic diagram of another preferred embodiment of the coolant drainage device for eliminating leakage from the power battery pack according to the present invention;

[0023] Figure 4 yes Figure 3 A schematic diagram of the drainage device;

[0024] The components in the attached diagram are labeled as follows: 1. Power battery pack housing; 11. First channel; 12. Second channel; 2. Outer shell; 21. Liquid absorption expansion body; 22. Valve stem; 221. Drainage channel; 23. Drainage port; 24. Balance air port; 25. Return spring; 26. Adjusting screw; 27. Ball valve core; 28. Gear; 29. ​​Rack and pinion; 3. Sealing gasket. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. The structures, proportions, sizes, etc., illustrated in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effects and objectives of the present invention, should still fall within the scope of the technical content disclosed in the present invention. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.

[0026] Please see Figure 1 and Figure 2 A draining device for preventing coolant leakage from a power battery pack includes a housing 2 fixedly connected to a power battery pack housing 1. A sealing gasket 3 is provided between the power battery pack housing 1 and the housing 2. A first channel 11 and a second channel 12 are provided between the power battery pack housing 1 and the housing 2. The first channel 11 and the second channel 12 include multiple aligned through holes on the power battery pack housing 1 and the housing 2. The first channel 11 and the second channel 12 are independent of each other, and coolant leaking from the power battery pack housing 1 will simultaneously enter the housing 2 through the first channel 11 and the second channel 12. The sealing gasket 3 mainly seals the area between the power battery pack housing 1 and the housing 2 except for the first channel 11 and the second channel 12, preventing coolant flowing through the first channel 11 and the second channel 12 from leaking to the outside between the power battery pack housing 1 and the housing 2.

[0027] An inner cavity with one open end is formed inside the outer casing 2. A liquid-absorbing expansion body 21 and a draining unit are sequentially arranged along the axis of the inner cavity. The power battery pack housing 1 is connected to the liquid-absorbing expansion body 21 and the draining unit. A first channel 11 connects the liquid-absorbing expansion body 21 to the power battery pack housing 1, and a second channel 12 connects the draining unit to the power battery pack housing 1. Part of the coolant leaking from the power battery pack housing 1 enters the outer casing 2 through the first channel 11 and is directly absorbed by the liquid-absorbing expansion body 21; the other part flows into the area where the draining unit is located in the outer casing 2.

[0028] The outer casing 2 has a drain port 23 that can be opened or closed via a drain unit. The liquid-absorbing expansion body 21 absorbs liquid and expands to push the drain unit to open the drain port 23, thereby connecting the power battery pack casing 1, the drain unit, and the drain port 23 to form a drainage channel. When the liquid-absorbing expansion body 21 expands, it acts on the drain unit, causing the drain unit to shift within its inner cavity. The drain unit then opens the drain port 23, allowing leaked coolant from the power battery pack casing 1 to flow out through the drain unit and drain port 23, thus preventing coolant accumulation within the power battery pack casing 1.

[0029] The drain unit is a valve stem 24 dynamically sealed within the inner cavity. A gap is formed between the middle of the valve stem 22 and the outer casing 2, creating a drain channel 221. The right end of the valve stem 22 blocks the drain port 23. Moving the valve stem 22 to the right separates the right end of the valve stem 22 from the drain port 23, thus opening the drain port 23. The valve stem 22 moves relative to the drain port 23 to open or close the drain port 23. The coolant in the power battery pack casing 1 is absorbed by the liquid-absorbing expansion body 21 through the first channel 11. After the liquid-absorbing expansion body 21 expands, it pushes the valve stem 22 to the right, thereby allowing the coolant to drain through the second channel 12, the drain channel 221, and the drain port 23. The valve stem 22 has an I-shaped cross-section, and both ends are dynamically sealed to the inner wall of the outer casing 2 through at least one sealing ring. In the initial state, as... Figure 1 The right end of valve stem 22 completely blocks the drain port 23, effectively isolating the external environment from the power battery pack housing 1 and preventing it from being affected by external factors. When coolant leaks from the power battery pack housing 1, the coolant enters the outer casing 2 along the first channel 11 and the second channel 12. Simultaneously, the liquid-absorbing expansion body 21 absorbs the coolant and begins to expand, pushing valve stem 22 to the right. Valve stem 22 then moves to the right until its right end is completely offset from the drain port 23. At this point, the drain channel 221 on valve stem 22 connects the second channel 12 and the drain port 23, forming a drainage channel. The coolant inside the power battery pack housing 1 is discharged from the drain port 23 along the drainage channel, achieving rapid discharge of the coolant. Figure 2 .

[0030] A return spring 25 is also provided at the right end of the inner cavity. The return spring 25 is pressed between the right end face of the drainage unit and the inner wall of the outer shell 2. A balance vent 24 is also provided at the right end of the inner cavity. When the valve stem 22 moves to the right, the gas inside the outer shell 2 will be discharged from the balance vent 24 to prevent the closed inner cavity from affecting the movement of the valve stem 22. At the same time, the return spring 25 is compressed. When the drainage is completely finished or the liquid absorption expansion body 21 dries and recovers, the return spring 25 provides a restoring force to the valve stem 22, so that the valve stem 22 returns to the initial position.

[0031] An adjusting screw 26 is threadedly connected to the opening of the inner cavity. The adjusting screw 26 presses the liquid-absorbing expansion body 21 against the drainage unit and seals the opening of the inner cavity. The liquid-absorbing expansion body 21 itself is expanded and tightened inside the outer shell 2. The liquid-absorbing expansion body 21 plays a sealing role, sealing the left side of the inner cavity. At the same time, the adjusting screw 26 can tighten the liquid-absorbing expansion body 21 to put the entire drainage device in the initial locked state. During installation, first insert the return spring 25 into the inner cavity, then insert the valve stem 22 into the inner cavity, then insert the liquid-absorbing expansion body 21, and finally screw the adjusting screw 26 into the appropriate position.

[0032] The liquid-absorbing expandable body 21 is a filler made of a polymeric resin material that absorbs ethylene glycol coolant. This polymeric resin filler is an expandable rod or gasket made from one or more of the following: phosphazene onium ionomer, docosahexamethacrylate and glycidyl methacrylate copolymer monomers, water-absorbing resin, and water-stopping (water-absorbing) expandable rubber. The water-stopping (water-absorbing) expandable rubber contains SAP (superabsorbent polymer), which expands to several times its own mass or volume after absorbing water, maintaining the rubber's inherent elasticity and strength while possessing a certain water-retention capacity. This water-stopping (water-absorbing) expandable rubber possesses the dual characteristics of elastic sealing and water-absorbing expansion sealing, offering excellent performance and safety. Furthermore, its ease of construction and wide applicability have led to its increasing popularity, earning it the title of "super sealing material." The aforementioned hydrophilic alcohol-absorbing filler expands significantly after wetting, and the expansion force pushes the device to overcome spring resistance, creating a leakage channel between the inside and outside of the battery pack, allowing the accumulated ethylene glycol coolant to be promptly discharged from the battery pack.

[0033] Example 2, please refer to Figure 3 and Figure 4 The drain unit is a ball valve core 27 with a drain hole. A gear 28 below the central shaft of the ball valve core 27 is connected to a rack 29. The rack 29 contacts a liquid-absorbing expansion body 21. The coolant in the power battery pack housing 1 is absorbed by the liquid-absorbing expansion body 21 through the first channel 11. After the expansion body 21 expands, it pushes the rack 29 to rotate the gear 28, thereby rotating the ball valve core 27. This allows the coolant to drain through the second channel 12, the drain hole, and the drain outlet 23. The rest is the same as in Embodiment 1.

[0034] Unlike existing technologies, this invention provides a draining device for leaking coolant from the power battery pack. This device can quickly drain coolant accumulated in low-lying areas of the power battery pack as soon as a leak occurs, thereby preventing more serious battery pack failures, short circuits, or thermal runaway, and protecting the safety of occupants and their property.

[0035] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A draining device for draining leaking coolant from a power battery pack, comprising a housing fixedly connected to the power battery pack housing, an inner cavity with one open end formed within the housing, a liquid-absorbing expansion body and a draining unit sequentially arranged along the axis of the inner cavity, the power battery pack housing being connected to the liquid-absorbing expansion body and the draining unit respectively through independent first and second channels; the housing having a drain port that is opened or closed by the draining unit, the liquid-absorbing expansion body being a filler of a polymer resin material that absorbs ethylene glycol coolant, the liquid-absorbing expansion body absorbing liquid and expanding to push the draining unit to open the drain port, thereby connecting the power battery pack housing, the draining unit and the drain port to form a drainage channel; The inner cavity is provided with a return spring at the end away from the liquid-absorbing expansion body, which is used to push the drainage unit to reset and close the drainage port after the liquid-absorbing expansion body loses water and shrinks. The power battery pack housing and the outer shell have a first channel and a second channel. The first channel connects the liquid absorption expansion body to the power battery pack housing, and the second channel connects the liquid drainage unit to the power battery pack housing. The drain unit is a valve stem dynamically sealed within the inner cavity. A gap exists between the middle of the valve stem and the outer casing, forming a drain channel. The valve stem moves relative to the drain port to open or close it. The coolant in the power battery pack casing is absorbed by the liquid-absorbing expansion body through the first channel. After the expansion body expands, it pushes the valve stem to the right, allowing the coolant to drain through the second channel, the drain channel, and the drain port. The right end of the valve stem blocks the drain port. Moving the valve stem to the right separates the right end of the valve stem from the drain port, thus opening it. The valve stem has an I-shaped cross-section, and both ends of the valve stem are dynamically sealed to the inner wall of the outer casing through sealing rings; The drain unit is a ball valve core with a drain hole. The gear below the central shaft of the ball valve core is connected to the rack rod. The rack rod is in contact with the liquid absorption expansion body. The coolant in the power battery pack housing is absorbed by the liquid absorption expansion body through the first channel. After the liquid absorption expansion body expands, it pushes the rack rod to drive the ball valve core to rotate, thereby causing the coolant to drain through the second channel, the drain hole and the drain outlet.

2. The drain device for excluding the coolant leaked from the power battery pack according to claim 1, characterized by, An adjusting screw is threadedly connected to the opening of the inner cavity. The adjusting screw presses the liquid-absorbing expansion body onto the drainage unit and closes the opening of the inner cavity.

3. The draining device for eliminating coolant leakage from the power battery pack according to claim 2, characterized in that, The right end of the inner cavity is also provided with a reset spring, which is pressed between the right end face of the drain unit and the inner wall of the outer shell. The right end of the inner cavity is also provided with a balance air port.

4. The draining device for eliminating coolant leakage from the power battery pack according to claim 3, characterized in that, A sealing gasket is provided between the power battery pack housing and the outer shell.

5. The draining device for eliminating coolant leakage from the power battery pack according to claim 4, characterized in that, The liquid-absorbing expander is a filler of a polymeric resin material that absorbs ethylene glycol coolant. The filler of the polymeric resin material is an expander rod or expander pad made by mixing one or more of the following: phosphazene onium ionomer, docosahexamethacrylate and glycidyl methacrylate copolymer monomer, water-absorbing resin, and water-stopping and water-absorbing expandable rubber.

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