Pressure release valve

Abstract

To provide a technique for actualizing a small-sized pressure release valve.SOLUTION: A pressure release valve 100 includes a valve member 28 for switching communication and closing of an opening part 52, an elastic member 20 for energizing the valve member in a rotating direction centering on an axial line parallel to a center axis of the opening part and energizing the valve member to the opening part side, an elastic member support part 26 for supporting the elastic member, and a fully closing holding stopper 12 for prohibiting the rotation of the valve member against the energizing force of the elastic member in the rotating direction, and holding the valve member at a fully closing position where the communication between the opening part and an external space is completely closed by the valve member. In the pressure release valve, when the valve member is free from holding of the fully closing holding stopper along with a pressure rise in a battery pack, the opening part is released to communicate between the opening part and the external space by the energizing force of the elastic member in the rotating direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This specification discloses technology relating to a pressure relief valve. [Background technology]

[0002] Patent Document 1 discloses a pressure relief valve that releases pressure in a battery pack when the pressure in the battery pack increases. The pressure relief valve in Patent Document 1 is a so-called swing valve, and a double torsion spring is disposed on the circumferential outside of a valve member that closes the opening of the battery pack. The extension of the double torsion spring is fixed to the center of the valve member. The double torsion spring biases the valve member toward the opening of the battery pack. In the pressure relief valve in Patent Document 1, when the pressure in the battery pack increases, the valve member rotates around the double torsion spring against the biasing force of the double torsion spring. As a result, the opening of the battery pack is opened, and the pressure in the battery pack is released. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-194719 A Summary of the Invention [Problem to be solved by the invention]

[0004] As described above, in the pressure release valve of Patent Document 1, the valve member rotates around the double torsion spring provided on the circumferential outer side of the valve member. Therefore, when the valve member opens (the opening of the battery pack is opened), the valve member, particularly the portion of the valve member opposite the position where the double torsion spring is provided, has a long operating distance. As a result, the size of the pressure release valve increases, and the size of the battery system (the battery pack to which the pressure release valve is attached) also increases. In order to realize a compact battery system, it is necessary to reduce the size of the pressure release valve. The present specification aims to provide a technology for realizing a compact pressure release valve. [Means for solving the problem]

[0005] The first technology disclosed in this specification may be a pressure relief valve that is attached to an opening of a battery pack, closes the opening and an external space, and communicates the opening and the external space as pressure in the battery pack increases. This pressure relief valve may include a valve member that switches between communication and blocking of the opening, an elastic member that urges the valve member in a rotational direction about an axis parallel to the central axis of the opening and urges the valve member toward the opening, an elastic member support part that supports the elastic member, and a fully closed holding stopper that prohibits the valve member from rotating against the urging force of the elastic member in the rotational direction and holds the valve member in a fully closed position where the valve member completely blocks communication between the opening and the external space. In addition, in this pressure relief valve, when the valve member is released from the holding of the fully closed holding stopper as pressure in the battery pack increases, the opening may be opened by the urging force of the elastic member in the rotational direction, and the opening may be communicated with the external space.

[0006] The second technology disclosed in this specification is a pressure relief valve of the first technology, which may further include a guide member that guides the valve member to the fully closed position by the biasing force of the elastic member toward the opening side after the pressure inside the battery pack is released.

[0007] A third technology disclosed in this specification is a pressure release valve of the first or second technology, which may be provided with an open valve retention stopper that retains the valve member in an open position maintaining communication between the opening and the external space against the biasing force of the elastic member in the rotational direction while releasing pressure within the battery pack.

[0008] A fourth technology disclosed in this specification is a pressure relief valve of any of the first to third technologies above, which has a case in which the elastic member and the elastic member support part are housed and which has a communication port communicating with the opening, and the valve member opens and closes the communication port. Effect of the Invention

[0009] According to the first technique, when the pressure inside the battery pack rises and the valve member opens the opening of the battery pack (communicating the opening with the outside space), the valve member moves slightly away from the opening and rotates around the axis of the valve member (axis parallel to the central axis of the opening). Therefore, the operating range of the valve member (the range in which the valve member is allowed to operate) is small, and the size of the valve member can be made small. Even if the distance between the valve member and the opening of the battery pack is short when the opening of the battery pack is opened, the opening area of ​​the opening can be ensured by the rotation of the valve member.

[0010] According to the second technology, after the pressure inside the battery pack has decreased (the pressure inside the battery pack has been released), the expansion force of the biasing member can be used to return the valve member to the fully closed position (the position where the valve member completely blocks the opening of the battery pack). In other words, when the pressure inside the battery pack increases, the operations from releasing the pressure inside the battery pack to closing the opening of the battery pack again can be performed automatically (without human intervention). As a result, it is possible to prevent the opening of the battery pack from being open when there is no need to open it (when the pressure inside the battery pack is normal).

[0011] According to the third technology, when releasing the pressure inside the battery pack, the position of the valve member can be held in an optimal position (the position most suitable for releasing pressure). For example, when releasing the pressure inside the battery pack, the position of the valve member can be held in a position where the opening area of ​​the opening is the widest. This makes it possible to quickly release (reduce) the pressure inside the battery pack when the pressure inside the battery pack increases.

[0012] According to the fourth technology, the pressure relief valve is unitized into a single component, and the battery system (battery pack with pressure relief valve installed) can be completed by simply assembling this one component (the pressure relief valve) to the battery pack. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view of a pressure relief valve according to a first embodiment (closed state). [Diagram 2] 1 is a cross-sectional view of a pressure relief valve according to a first embodiment (open state). [Diagram 3] 1 shows the relationship between the valve member and a communication hole provided in the fixed portion (closed state). [Figure 4] 1 shows the relationship between the valve member and a communication hole provided in the fixed portion (open state). [Diagram 5] 4 is a cross-sectional view of a pressure relief valve according to a second embodiment. [Figure 6] 13A to 13C are diagrams illustrating the operation of a knob portion of the pressure relief valve of the second embodiment. [Figure 7] 13 is a cross-sectional view of a pressure relief valve according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] (First Example) The pressure relief valve 100 will be described with reference to Figures 1 to 4. The pressure relief valve 100 is attached to the opening 52 of the battery pack 50. The pressure relief valve 100 includes a case 30, a valve member 28 disposed in the case 30, and a coil spring 20 that biases the valve member 28. The coil spring 20 is an example of an elastic member.

[0015] As shown in FIG. 1, the case 30 includes a fixed portion 10 attached to the battery pack 50, a side wall portion 16 surrounding the periphery of the valve member 28, and a cover portion 26 covering the upper side of the valve member 28 (the side opposite the fixed portion 10 with respect to the valve member 28). The fixed portion 10 is provided with a communication hole 32, which communicates with an opening 52 of the battery pack 50. The fixed portion 10 covers the entire surface of the opening 52. Therefore, if the communication hole 32 were not provided in the fixed portion 10, the fixed portion 10 would completely close the opening 52. The fixed portion 10 is provided with a full-closed hold stopper 12. The full-closed hold stopper 12 will be described later.

[0016] The side wall portion 16 connects the fixed portion 10 and the cover portion 26, and maintains a distance between the fixed portion 10 and the cover portion 26. The side wall portion 16 also surrounds the entire circumferential direction of the valve member 28. An exhaust passage 14 that communicates the inside and outside of the side wall portion 16 is provided in a part of the side wall portion 16. The cover portion 26 covers the entire upper part of the valve member 28. In other words, the cover portion 26 is connected to the entire circumferential direction of the side wall portion 16. Therefore, the space in which the valve member 28 is disposed is blocked from the external space of the pressure release valve 100 by the cover portion 26 and the side wall portion 16, except for the exhaust passage 14. The cover portion 26 also supports one end of the coil spring 20. The cover portion 26 is an example of an elastic member support portion. The cover portion 26 also has an open valve retention stopper 27 and a closed valve guide 24. The open valve retention stopper 27 extends from the cover portion 26 toward the fixed portion 10. The open valve stopper 27 and the closed valve guide 24 will be described later.

[0017] The valve member 28 is biased toward the fixed part 10 (the opening 52 side of the battery pack 50) by the axial biasing force of the coil spring 20 (the extension force of the coil spring 20). Therefore, when the pressure inside 54 of the battery pack 50 is normal (less than a predetermined value), the valve member 28 is in contact with the surface of the fixed part 10. The valve member 28 is also biased by the coil spring 20 in a rotational direction about the central axis CL. The central axis CL is the rotation axis of the valve member 28 and is the central axis of the communication hole 32 and the opening 52. The valve member 28 is provided with a shaft 21 that extends toward the cover part 26. The shaft 21 is provided with a guide protrusion 22 that engages with the above-mentioned closing valve guide 24. The guide protrusion 22 will also be described later.

[0018] As described above, the fixed part 10 is provided with the full-closed hold stopper 12. The full-closed hold stopper 12 is provided on the surface of the fixed part 10. Therefore, when the valve member 28 is in contact with the surface of the fixed part 10, the full-closed hold stopper 12 comes into contact with the valve member 28 and inhibits the valve member 28 from rotating against the biasing force in the rotation direction applied to the valve member 28 from the coil spring 20. The full-closed hold stopper 12 is provided at a position where the rotation of the valve member 28 stops at the full-closed position where the valve member 28 completely closes the communication hole 32. As described above, the communication hole 32 communicates with the opening 52, and the fixed part 10 covers the entire surface of the opening 52. Therefore, when the valve member 28 is in contact with the full-closed hold stopper 12, communication between the opening 52 of the battery pack 50 and the external space is completely blocked. Note that when the valve member 28 is in contact with the full-closed hold stopper 12, the valve member 28 and the open valve hold stopper 27 are not in contact with each other.

[0019] As shown in FIG. 2, when the pressure in the inside 54 of the battery pack 50 rises, the valve member 28 moves away from the fixed part 10 against the axial biasing force of the coil spring 20 (the valve member 28 moves to the cover part 26). As a result, the valve member 28 and the full-close retention stopper 12 are out of contact, and the valve member 28 rotates due to the biasing force of the coil spring 20 in the rotational direction, and the communication hole 32 is opened. As a result, the opening 52 of the battery pack 50 is opened, and the opening 52 communicates with the external space of the pressure release valve 100 through the exhaust passage 14. This allows the inside 54 of the battery pack 50 to communicate with the external space, and the pressure in the inside 54 can be reduced. The valve member 28 can switch between communication and blocking of the opening 52, and maintain the pressure in the inside 54 at or below a predetermined value. In addition, when the valve member 28 moves away from the fixed part 10, the valve member 28 rotates around the central axis CL due to the biasing force of the coil spring 20 in the rotational direction. When the valve member 28 rotates, it comes into contact with the full-open hold stopper 27, stopping the rotation of the valve member 28. The full-open hold stopper 27 comes into contact with the valve member 28 and prohibits the valve member 28 from rotating against the biasing force applied to the valve member 28 by the coil spring 20 in the rotational direction.

[0020] Here, the valve member 28 and the fixed part 10 (the communication hole 32 provided in the fixed part 10) will be described with reference to Figures 3 and 4. Figure 3 shows a state in which the valve member 28 closes the communication hole 32 (see also Figure 1). Figure 4 shows a state in which the valve member 28 opens the communication hole 32 (see also Figure 2).

[0021] As shown in FIG. 3, the fixed portion 10 is circular and has a communication hole 32 at the center. The communication hole 32 is substantially rectangular. The valve member 28 is positioned by the fully closed stopper 12 (rotation around the central axis CL is prohibited) and blocks the entire communication hole 32. That is, the valve member 28 is stopped at the fully closed position. The valve member 28 is also substantially rectangular. As shown in FIG. 4, when the valve member 28 rotates around the central axis CL, the valve member 28 is positioned by the open valve stopper 27 (rotation around the central axis CL is prohibited) and stops at a position rotated about 90 degrees (open position). As a result, a part of the communication hole 32 is completely opened (the valve member 28 is not present in a part above the communication hole 32), and the communication between the opening 52 and the external space is reliably maintained. As a result, the resistance when the gas in the interior 54 of the battery pack 50 moves through the communication hole 32 is reduced, and the pressure in the interior 54 can be quickly reduced.

[0022] Returning to Figs. 1 and 2, the operation of the valve member 28 will be described. As described above, the closed valve guide 24 is provided on the cover portion 26, and the guide protrusion 22 is provided on the shaft 21. The closed valve guide 24 has an inclined surface and is an arc shape centered on the central axis CL. The guide protrusion 22 also has an inclined surface. The inclined surface of the closed valve guide 24 and the inclined surface of the guide protrusion 22 are in contact with each other. The closed valve guide 24 and the guide protrusion 22 form the guide portion 23. When the pressure in the interior 54 of the battery pack 50 increases (when the valve member 28 moves from the fully closed position to the open position), the valve member 28 operates in a state in which the inclined surface of the closed valve guide 24 and the inclined surface of the guide protrusion 22 are in contact with each other (Fig. 1 → Fig. 2). Thereafter, when the pressure inside 54 of battery pack 50 decreases, the axial biasing force of coil spring 20 moves valve member 28 toward opening 52 and rotates about central axis CL (rotating in the opposite direction to when the valve was opened) to return to the fully closed position (FIG. 2 →FIG. 1). Even when valve member 28 returns to the fully closed position, valve member 28 operates with the inclined surface of valve closing guide 24 and the inclined surface of guide protrusion 22 in contact with each other. This allows valve member 28 to reliably return to the fully closed position. By providing guide portion 23, valve member 28 can automatically return to the fully closed position after pressure inside 54 of battery pack 50 is released.

[0023] (Second Example) The pressure relief valve 100a will be described with reference to Figures 5 and 6. The pressure relief valve 100a is a modified example of the pressure relief valve 100. For the pressure relief valve 100a, the same reference numbers as those of the pressure relief valve 100 are used to denote the same components as those of the pressure relief valve 100, and descriptions thereof may be omitted.

[0024] The pressure release valve 100a includes a knob portion 60 fixed to the valve member 28. In addition, in the pressure release valve 100a, the cover portion 26 is provided with a through hole 25 through which the knob portion 60 passes. The knob portion 60 is fixed to the surface of the valve member 28 (the surface opposite to the surface that contacts the fixed portion 10). The knob portion 60 passes through the through hole 25 and extends to above the cover portion 26. Therefore, the knob portion 60 can be touched from the outside of the pressure release valve 100a. In addition, the through hole 25 is in the shape of a circular arc centered on the central axis CL, and is slightly longer than the movable range of the knob portion 60 (the operating range of the valve member 28). The pressure release valve 100a does not include the guide portion 23 that the pressure release valve 100 includes.

[0025] The knob portion 60 is fixed to the valve member 28, and therefore moves around the central axis CL as the valve member 28 rotates. For example, the knob portion 60 is located at the position indicated by the dashed line when the valve member 28 is in the fully closed position, and is located at the position indicated by the solid line when the valve member 28 is in the open position (see also Figs. 3 and 4). By providing the knob portion 60, the valve member 28 can be manually returned to the fully closed position after the pressure in the interior 54 of the battery pack 50 is released. That is, the valve member 28 can be returned to the fully closed position without providing the guide portion 23 that the pressure release valve 100 includes.

[0026] As described above, the pressure relief valve 100 automatically returns the valve member 28 to the fully closed position by the axial biasing force of the coil spring 20 (the force of the coil spring 20 expanding). In this case, it is necessary to highly adjust the axial biasing force of the coil spring 20 so that the valve member 28 opens the communication hole 32 when the pressure inside the battery pack 50 increases, and the valve member 28 returns to the fully closed position when the pressure inside the battery pack 50 decreases to a predetermined value. However, in the case of the pressure relief valve 100a, the valve member 28 can be manually returned to the fully closed position, so that the valve member 28 can be reliably returned to the fully closed position without highly adjusting the biasing force of the coil spring 20.

[0027] (Third Example) The pressure relief valve 200 will be described with reference to Fig. 7. The pressure relief valve 200 is a modified example of the pressure relief valve 100. For the pressure relief valve 200, the same components as those of the pressure relief valve 100 are given the same reference numbers as those of the pressure relief valve 100, and descriptions thereof may be omitted.

[0028] In the pressure release valve 200, a second communication hole 232 is provided in the cover portion 26. In the pressure release valve 200, the exhaust passage 14 provided in the pressure release valve 100 is not provided in the side wall portion 16. In the pressure release valve 200, the fixed portion 10 supports one end of the coil spring 20. The fixed portion 10 is an example of an elastic member support portion. In addition, the valve member 28 is biased against the surface of the cover portion 26 by the axial biasing force of the coil spring 20 (compressive force of the coil spring 20). The fully closed retention stopper 12 is provided on the surface of the cover portion 26, and is provided at a position where the rotation of the valve member 28 stops when the valve member 28 is in the fully closed position where the valve member 28 completely closes the communication hole 232.

[0029] In the pressure release valve 200, when the pressure inside 54 of the battery pack 50 rises, the valve member 28 moves away from the cover part 26 against the axial biasing force of the coil spring 20. Similarly to the pressure release valve 100, the valve member 28 and the fully closed retention stopper 12 are out of contact with each other, and the valve member 28 rotates around the central axis CL due to the biasing force of the coil spring 20 in the rotational direction. In the pressure release valve 200, the valve member 28 is located outside the case 30. Therefore, after the pressure inside 54 of the battery pack 50 is released, the valve member 28 can be easily returned to the fully closed position. That is, the pressure release valve 200 can omit structures such as the guide part 23 of the pressure release valve 100 and the knob part 60 of the pressure release valve 100a. In addition, the pressure release valve 200 does not need to be disassembled when performing maintenance (for example, removing foreign matter between the valve member 28 and the cover part 26).

[0030] (Other embodiments) In the above embodiment, when the pressure inside 54 of battery pack 50 rises, the fully closed retention stopper 12 may be broken by the pressure, and valve member 28 may operate in the rotational direction. Although valve member 28 cannot be returned to the fully closed position again, it can function as a pressure relief valve if the purpose is to suppress a pressure rise inside battery pack 50 just once.

[0031] In the above embodiment, the rotation axis of the valve member 28, the central axis of the communication hole 32, and the central axis of the opening 52 are aligned on the central axis CL. However, the rotation axis of the valve member 28, the central axis of the communication hole 32, and the central axis of the opening 52 only need to be parallel to each other and do not necessarily have to be aligned.

[0032] In the pressure relief valves 100, 100a, the fixing part 10 having the communication hole 32 is fixed to the opening 52 of the battery pack 50, and the valve member 28 closes the communication hole 32. However, the valve member 28 may directly close the opening 52 of the battery pack 50.

[0033] In the pressure relief valves 100 and 100a, the side wall portion 16 surrounds the entire circumference of the valve member 28, except for the portion where the exhaust passage 14 is formed. However, the side wall portion does not necessarily surround the entire circumference of the valve member 28. For example, instead of the side wall portion 16, a plurality of columnar side wall portions that maintain the distance between the fixing portion 10 and the cover portion 26 may be provided. In this case, it is possible to omit providing an exhaust passage in the side wall portion. Also, in the pressure relief valve 100, the cover portion 26 covers the entire upper portion of the valve member 28. The cover portion 26 does not necessarily cover the entire upper portion of the valve member 28 either.

[0034] In the pressure release valves 100, 100a, the open valve holding stopper 27 may be omitted. When the pressure inside the battery pack 50 rises, the valve member 28 is out of contact with the fixed portion 10, and the communication hole 32 is open. Therefore, by omitting the open valve holding stopper 27, the pressure inside the battery pack 50 can be released even if the valve member 28 is not stopped at the open position.

[0035] The knob portion 60 of the pressure relief valve 100a may be added to the pressure relief valve 100. This allows the valve member 28 to be returned to the fully closed position more reliably. In addition, the pressure relief valve 100 does not necessarily have to include the guide portion 23. Similarly, the pressure relief valve 100a does not necessarily have to include the knob portion 60. For example, when returning the valve member 28 to the fully closed position again, the cover portion 26 may be removed and the position of the valve member 28 may be adjusted.

[0036] Although the embodiments of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings achieves multiple objectives simultaneously, and achieving one of the objectives itself has technical utility. [Explanation of symbols]

[0037] 10: Fixed part (elastic member support part) 12: Fully closed stopper 20: Coil spring (elastic member) 26: Cover (elastic member support part) 28: Valve member 50: Battery pack 52: Opening 100: Pressure relief valve CL: Central axis

Claims

1. a pressure relief valve attached to an opening of a battery pack, closing off a gap between the opening and an external space, and communicating the opening and the external space with an increase in pressure in the battery pack, a valve member that switches between communication and blocking of the opening; an elastic member that urges the valve member in a rotational direction about an axis parallel to a central axis of the opening and urges the valve member toward the opening; an elastic member support portion that supports the elastic member; a fully closed retention stopper that prohibits the valve member from rotating against the biasing force of the elastic member in the rotational direction and retains the valve member in a fully closed position where the valve member completely blocks communication between the opening and the external space, A pressure relief valve in which, when the valve member is released from the fully closed retention stopper due to an increase in pressure inside the battery pack, the opening is opened by the biasing force of the elastic member in the rotational direction, connecting the opening to the external space.

2. 2. The pressure relief valve of claim 1, the pressure release valve further comprising a guide member that guides the valve member to the fully closed position by the biasing force of the elastic member toward the opening side after the pressure inside the battery pack is released.

3. 3. The pressure relief valve according to claim 2, a pressure release valve including an open valve retention stopper that holds the valve member in an open position maintaining communication between the opening and the external space against the rotational force of the elastic member while releasing pressure within the battery pack.

4. A pressure relief valve according to any one of claims 1 to 3, a case in which the elastic member and the elastic member support portion are housed and which is provided with a communication port communicating with the opening, The valve member opens and closes the communication port.

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