Pressure release valve

Abstract

To provide a small-sized pressure release valve.SOLUTION: A pressure release valve 10 comprises: a case part including an opening and fixed to a surface of a housing; a cover part 20 supported by the case part so as to be rotatable in a rotation direction parallel to the surface of the housing; and a first energization member for energizing the cover part 20 so that the cover part 20 rotates from a closed position to an open position in the rotation direction. The cover part 20 covers the opening in the cover part 20 when in the closed position, and opens the opening in the cover part 20 when in the open position. The case part includes a stopper to engage with the cover part 20 when it is in the closed position. The pressure release valve is configured so that the engagement of the stopper and the cover part is released when the inner pressure of the housing exceeds a threshold.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pressure relief valve for adjusting the pressure inside a housing.

Background Art

[0002] A pressure relief valve is a device for adjusting the pressure inside a housing. The housing is, for example, a battery pack mounted on an automobile. Inside the battery pack, devices such as battery cells are housed and sealed. The pressure relief valve is attached to a housing such as a battery pack. For example, the pressure relief valve is arranged to cover an opening formed in the housing. When the pressure inside the housing exceeds a threshold value, the pressure relief valve operates to release the gas inside the housing to the outside. The pressure relief valve can prevent the devices inside the housing from being damaged due to an increase in pressure.

[0003] Some pressure relief valves have been proposed. For example, Patent Document 1 discloses a pressure relief valve including a base portion attached to an opening of a housing and a cover portion covering the base portion. An urging force is applied to the cover portion toward the base portion. When the internal pressure exceeds a threshold value, the cover portion moves away from the base portion in the normal direction of the surface of the housing. The gas inside the housing is released to the outside through the gap between the base portion and the cover portion and the gap between the cover portion and the housing. For example, Patent Document 2 discloses a pressure relief valve including a plurality of small holes penetrating a wall of a housing and a sheet covering the small holes. When the internal pressure exceeds a threshold value, the sheet breaks and the small holes are opened. The gas inside the housing is released to the outside through the small holes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the pressure relief valve described in Patent Document 1, the gas flow is restricted by the gaps between the base part and the cover part, and between the cover part and the housing. Also, since the dimensions of the pressure relief valve in the normal direction of the housing surface become large, the degree of freedom in layout design is small. In the pressure relief valve described in Patent Document 2, the gas flow is obstructed by the broken sheet.

[0006] An object of the present invention is to provide a pressure relief valve that can solve such problems.

Means for Solving the Problems

[0007] The present invention is a pressure relief valve that releases gas from a housing when the internal pressure of the gas inside the housing rises, including an opening, a case part fixed to the surface of the housing, a cover part supported by the case part so as to be rotatable in a rotational direction parallel to the surface of the housing, and a first biasing member that biases the cover part so that the cover part rotates from a closed position to an open position in the rotational direction. In the closed position, the cover part covers the opening of the case part, and in the open position, the cover part opens the opening of the case part. The case part includes a stopper that engages with the cover part in the closed position. The pressure relief valve is configured such that when the internal pressure of the housing exceeds a threshold value, the engagement between the stopper and the cover part is released.

[0008] The pressure relief valve according to the present invention may include a second biasing member that biases the cover part in a direction toward the case part.

[0009] In the pressure release valve according to the present invention, the cover portion may include a first lock that engages with the stopper of the case portion in the closed position.

[0010] In the pressure release valve according to the present invention, the cover portion may include a cylindrical portion. The case portion may be inserted into the cylindrical portion and may include a shaft portion that functions as a rotation axis in the rotation direction. The first lock may protrude outward from the cylindrical portion.

[0011] In the pressure release valve according to the present invention, the cover portion may include a second lock that engages with the stopper of the case portion in the open position.

Advantages of the Invention

[0012] According to the present invention, the flow rate of the gas discharged to the outside can be increased. In addition, the degree of freedom in the layout design of the pressure release valve can be increased.

Brief Description of the Drawings

[0013]

Figure 1

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Embodiments for Carrying Out the Invention

[0014] Embodiments of the present invention will be described with reference to the drawings. In the drawings attached to this specification, for the convenience of easy understanding, the scale, the aspect ratio of the vertical and horizontal dimensions, etc. are appropriately changed and exaggerated from those of the actual object.

[0015] FIG. 1 is a perspective view showing an example of the pressure release valve 10. The pressure release valve 10 is attached to the housing 100. FIG. 2 is a partial cross-sectional view showing the pressure release valve 10 attached to the housing 100. The housing 100 is, for example, a battery pack mounted on an automobile. Inside the battery pack, devices such as battery cells are housed and sealed. The housing 100 includes a front surface 101 and a back surface 102. The front surface 101 is in contact with the external atmosphere of the housing 100. The back surface 102 is in contact with the internal space sealed by the housing 100. The housing 100 includes a vent hole 103 that penetrates the housing 100. The pressure release valve 10 is attached to the housing 100 so as to cover the vent hole 103.

[0016] The pressure release valve 10 operates to release the gas inside the housing 100 to the outside when the pressure inside the housing 100 exceeds a threshold value. The pressure inside the housing 100 is also referred to as the internal pressure.

[0017] The pressure relief valve 10 will be described in detail. FIG. 3 is an exploded view showing the pressure relief valve 10. The pressure relief valve 10 includes a cover portion 20, an end lock 29, a first seal portion 30, a second seal portion 35, a first biasing member 40, a second biasing member 45, and a case portion 50. By assembling the cover portion 20, the end lock 29, the first seal portion 30, the second seal portion 35, the first biasing member 40, the second biasing member 45, and the case portion 50, the modularized pressure relief valve 10 is obtained. The pressure relief valve 10 is attached to the housing 100 in a modularized state.

[0018] The cover portion 20 is supported so as to be rotatable in the rotational direction D1 parallel to the surface 101 of the housing 100. When the pressure inside the housing 100 exceeds the threshold value, the cover portion 20 rotates from the closed position to the open position in the rotational direction D1. FIGS. 1 and 2 show the state where the cover portion 20 is in the closed position. When the cover portion 20 is in the closed position, the vent hole 103 of the housing 100 is covered by the pressure relief valve 10. When the cover portion 20 is in the open position, the pressure relief valve 10 communicates the vent hole 103 with the outside. Thus, in the present embodiment, by rotating the cover portion 20, the gas inside the housing 100 can be released to the outside.

[0019] Each component of the pressure relief valve 10 will be described in detail with reference to FIGS. 1 to 5. FIG. 4 is a view showing the cover portion 20 when viewed from below. FIG. 5 is a view showing the case portion 50 when viewed from below. "Viewed from below" means viewing the pressure relief valve 10 in the direction from the housing 100 toward the pressure relief valve 10.

[0020] The normal direction of the surface 101 of the housing 100 is also referred to as the vertical direction and is represented by the reference sign D2. Among the vertical directions, the direction from the pressure relief valve 10 toward the housing 100 is also referred to as the downward direction or the lower side. Among the vertical directions, the direction from the housing 100 toward the pressure relief valve 10 is also referred to as the upward direction or the upper side.

[0021] (Case portion) The case part 50 is fixed to the housing 100. The case part 50 includes a bottom surface 51, a top surface 52, an opening 53, and a shaft part 56. The bottom surface 51 faces the surface 101 of the housing 100. The top surface 52 is located on the opposite side of the bottom surface 51 in the vertical direction D2. The opening 53 penetrates the case part 50 from the bottom surface 51 to the top surface 52. The shaft part 56 extends in the vertical direction D2. The shaft part 56 functions as a rotation axis in the rotation direction D1.

[0022] The case part 50 includes at least one opening 53. The case part 50 may include two or more openings 53. In the present embodiment, the case part 50 includes two openings 53 in an axisymmetric relationship. The contour of the opening 53 may include an arc centered on the shaft part 56.

[0023] As shown in FIGS. 3 and 5, the case part 50 may include a first accommodating part 54 located on the bottom surface 51. The first accommodating part 54 accommodates the first seal part 30. The case part 50 may include a second accommodating part 55 located on the top surface 52. The second accommodating part 55 accommodates the second seal part 35. The second accommodating part 55 surrounds the opening 53 in a plan view. "Plan view" means looking at an object along the normal direction of the surface 101.

[0024] The case part 50 may include a stopper 57. The stopper 57 can regulate the position of the cover part 20 in the rotation direction D1. For example, the stopper 57 engages with the cover part 20 in the closed position. The stopper 57 may protrude upward from the top surface 52.

[0025] The case part 50 may include a support part 58. The support part 58 supports the first end 41 of the first biasing member 40 in the rotation direction D1. For example, the support part 58 prevents the first end 41 from rotating in the rotation direction D1 by contacting the first end 41 of the first biasing member 40.

[0026] The case portion 50 may include a fastening portion 59. The fastening portion 59 is, for example, a hole into which a fastener 60 shown in FIG. 3 is inserted. The fastener 60 is, for example, a bolt. By inserting the fastener 60 into the fastening portion 59 of the case portion 50 and a hole (not shown) of the housing 100 and fixing the fastener 60 with a nut or the like (not shown), the case portion 50 is fixed to the housing 100.

[0027] (First biasing member) The first biasing member 40 biases the cover portion 20 so that the cover portion 20 rotates from the closed position to the open position in the rotational direction D1. The first biasing member 40 is, for example, a spring laminated in the vertical direction D2. The first biasing member 40 includes the above-described first end 41 in contact with the case portion 50 and a second end 42 in contact with the cover portion 20.

[0028] (Second biasing member) The second biasing member 45 biases the cover portion 20 in the direction in which the cover portion 20 faces the case portion 50. The second biasing member 45 is, for example, a coil spring that can expand and contract in the vertical direction D2. The second biasing member 45 includes a lower end 46 in contact with the bottom portion 242 of the cylindrical portion 24 of the cover portion 20 and an upper end 47. The upper end 47 may be in contact with the upper portion 292 of the end lock 29.

[0029] (Cover portion) The cover portion 20 includes a lower surface 21, an upper surface 22, and an opening 23. The lower surface 21 faces the upper surface 52 of the case portion 50. The upper surface 22 is located on the opposite side of the lower surface 21 in the vertical direction D2. The opening 23 penetrates the cover portion 20 from the lower surface 21 to the upper surface 22.

[0030] In the closed position, the cover portion 20 covers the opening 53 of the case portion 50. For example, in the closed position, the opening 23 of the cover portion 20 does not overlap with the opening 53 of the case portion 50 in a plan view. In the open position, the cover portion 20 opens the opening 53 of the case portion 50. For example, in the open position, the opening 23 of the cover portion 20 overlaps with the opening 53 of the case portion 50 in a plan view. Thereby, the gas inside the housing 100 is discharged to the outside through the opening 53 of the case portion 50 and the opening 23 of the cover portion 20.

[0031] The cover portion 20 includes at least one opening 23. The opening 23 may include two or more openings 23. In the present embodiment, the cover portion 20 includes two openings 23, similar to the case portion 50. The contour of the opening 23 may include an arc centered on the shaft portion 56. In a plan view, the contour of the opening 23 may be surrounded by the opening 53. In a plan view, the opening 23 may surround the contour of the opening 53.

[0032] The cover portion 20 is supported by the shaft portion 56 of the case portion 50 so as to be rotatable in the rotational direction D1. For example, as shown in FIG. 4, the cover portion 20 may include a cylindrical portion 24. The cylindrical portion 24 may protrude downward from the lower surface 21. The cylindrical portion 24 is connected to the shaft portion 56 of the case portion 50. For example, the cylindrical portion 24 includes a cylindrical side portion 241 and a bottom portion 242 in which a hole into which the shaft portion 56 is inserted is formed.

[0033] An urging force is applied to the cover portion 20 from the first urging member 40 in the rotational direction D1. To counter the urging force, as shown in FIG. 4, the cover portion 20 may include a first lock 26. The first lock 26 engages with the stopper 57 of the case portion 50 in the closed position. Thereby, rotation of the cover portion 20 with respect to the case portion 50 is prevented in the closed position. As shown in FIG. 4, the first lock 26 may protrude radially outward from the side portion 241 of the cylindrical portion 24.

[0034] As shown in FIG. 4, the cover portion 20 may include a second lock 27. The second lock 27 engages with a stopper 57 of the case portion 50 in the rotational direction D1, as will be described later. Thereby, the cover portion 20 can be stationary at the open position in the rotational direction D1. As shown in FIG. 4, the second lock 27 may project radially outward from a side portion 241 of the cylindrical portion 24.

[0035] The cover portion 20 may be supported by the case portion 50 so as to be movable in the vertical direction D2 between an upper position and a lower position. The first lock 26 of the cover portion 20 engages with the stopper 57 of the case portion 50 at the lower position. The upper position is above the lower position. The first lock 26 of the cover portion 20 cannot engage with the stopper 57 of the case portion 50 at the upper position. The second lock 27 of the cover portion 20 can engage with the stopper 57 of the case portion 50 at the upper position.

[0036] (End lock) The end lock 29 is fixed to the case portion 50. For example, the end lock 29 includes a cylindrical side portion 291 into which the shaft portion 56 of the case portion 50 is fitted, and an upper portion 292. The upper portion 292 contacts the second biasing member 45 from above.

[0037] (First seal portion) The first seal portion 30 is located between the lower surface 51 of the case portion 50 and the surface 101 of the housing 100. The first seal portion 30 surrounds a plurality of openings 53 in a plan view. The first seal portion 30 is, for example, a gasket.

[0038] (Second seal portion) The second seal portion 35 is located between the upper surface 52 of the case portion 50 and the lower surface 21 of the cover portion 20. One second seal portion 35 may surround one opening 23 in a plan view. In this case, the number of the second seal portions 35 is the same as the number of the openings 23. The second seal portion 35 is, for example, a gasket.

[0039] Next, with reference to FIGS. 6 to 9, the positional relationship of the components of the pressure release valve 10 will be described in detail. FIG. 6 is a side view showing the pressure release valve 10 in a state where the cover portion 20 is in the closed position. FIG. 7 is a longitudinal sectional view showing the pressure release valve 10 in a state where the cover portion 20 is in the closed position. FIG. 8 is a sectional view showing the first biasing member 40 in a state where the cover portion 20 is in the closed position. FIG. 8 corresponds to a sectional view taken along line A-A of FIG. 6. FIG. 9 is a view showing a case where the cylindrical portion 24 of the cover portion 20 and the locks 26, 27 are cut by a plane parallel to the rotational direction.

[0040] As shown in FIG. 7, a shaft portion 56 may be inserted into the first biasing member 40 and the second biasing member 45. An end lock 29 fitted into the shaft portion 56 may be inserted into the second biasing member 45.

[0041] The second biasing member 45 may be disposed between the bottom portion 242 of the cylindrical portion 24 of the cover portion 20 and the upper portion 292 of the end lock 29 in a compressed state in the vertical direction D2. In this case, a restoring force that tends to extend in the vertical direction D2 is generated in the second biasing member 45. As described above, the end lock 29 is fixed to the case portion 50. Therefore, the restoring force of the second biasing member 45 acts as a biasing force that biases the cover portion 20 toward the case portion 50.

[0042] As shown in FIGS. 8 and 9, the first biasing member 40 is attached to the cover portion 20 and the case portion 50 in a state where a restoring force R in the rotational direction D1 is generated in the closed position. As shown in FIG. 9, the first lock 26 of the cover portion 20 in the closed position engages with the stopper 57 of the case portion 50 in the rotational direction D1. The engagement between the first lock 26 and the stopper 57 prevents the cover portion 20 from rotating due to the restoring force R. In FIG. 8, since the first biasing member 40 is viewed from below, the direction of the restoring force R in FIG. 8 is opposite to the direction of the restoring force R in FIG. 9.

[0043] As shown in FIG. 9, the second lock 27 of the cover portion 20 may have a height H2 that is greater than the height H1 of the first lock 26. As shown in FIG. 9, the second lock 27 may extend in the vertical direction D2 below the first lock 26.

[0044] Next, an example of the operation of the pressure release valve 10 will be described. Assume that the pressure release valve 10 is attached to the battery pack.

[0045] When the battery pack is operating normally, the cover portion 20 is in the closed position shown in FIGS. 1, 7 to 9. The cover portion 20 is biased in the rotational direction D1 by the first biasing member 40. On the other hand, the first lock 26 of the cover portion 20 engages with the stopper 57 of the case portion 50 in the rotational direction D1. Since the cover portion 20 cannot rotate in the rotational direction D1, the state where the opening 23 of the cover portion 20 does not overlap the opening 53 of the case portion 50 is maintained as shown in FIGS. 1, 7 to 9. Further, the second biasing member 45 generates a biasing force that biases the cover portion 20 toward the housing 100. For this reason, the opening 53 of the case portion 50 is sealed by the lower surface 21 of the cover portion 20 and the second seal portion 35.

[0046] When the internal pressure of the housing 100 of the battery pack exceeds a predetermined threshold value, the force applied by the internal pressure to the cover portion 20 becomes greater than the force applied by the second biasing member 45 to the cover portion 20. As a result, the cover portion 20 moves upward from the lower position. The cover portion 20 moves upward to the upper position where the force applied by the internal pressure to the cover portion 20 and the force applied by the second biasing member 45 to the cover portion 20 are balanced. FIG. 10 is a partial cross-sectional view showing the pressure release valve 10 in a state where the cover portion 20 is in the upper position. FIG. 11 is a longitudinal cross-sectional view showing the pressure release valve 10 in a state where the cover portion 20 is in the upper position. FIG. 12 is a view showing the cylindrical portion 24 and the locks 26, 27 in a state where the cover portion 20 is in the upper position.

[0047] As shown in Fig. 12, when the cover portion 20 moves to the upper position, the engagement between the stopper 57 of the case portion 50 and the first lock 26 of the cover portion 20 is released. Therefore, the cover portion 20 in the upper position can rotate to the open position in the rotation direction D1 by the biasing force of the first biasing member 40.

[0048] Fig. 13 is a view showing the cylindrical portion 24 and the locks 26 and 27 in a state where the cover portion 20 is in the open position. As shown in Fig. 13, when the cover portion 20 rotates to the open position, the second lock 27 of the cover portion 20 engages with the stopper 57 of the case portion 50. Thereby, the rotation of the cover portion 20 is stopped. Fig. 14 is a cross-sectional view showing the first biasing member 40 in a state where the cover portion 20 is in the open position. In Fig. 14, since the first biasing member 40 is viewed from below, the direction of the rotation direction D1 in Fig. 14 is opposite to the direction of the rotation direction D1 in Fig. 13. The positional relationship between the first lock 26 and the second lock 27 may be determined such that the second seal portion 35 surrounds the opening 23 in a plan view in the open position.

[0049] Fig. 15 is a partial cross-sectional view showing the pressure release valve 10 in a state where the cover portion 20 is in the open position. The opening 23 of the cover portion 20 overlaps with the opening 53 of the case portion 50 in the open position. Therefore, the gas inside the housing 100 is discharged to the outside through the vent hole 103 of the housing 100, the opening 53 of the case portion 50, and the opening 23 of the cover portion 20.

[0050] As the gas is discharged to the outside, the internal pressure decreases. When the force applied by the internal pressure to the cover portion 20 becomes smaller than the force applied by the second biasing member 45 to the cover portion 20, the cover portion 20 moves to the lower position by the restoring force of the second biasing member 45. On the other hand, the second lock 27 of the cover portion 20 continues to engage with the stopper 57 of the case portion 50. Since the cover portion 20 cannot rotate in the rotation direction D1, the state where the opening 23 of the cover portion 20 overlaps with the opening 53 of the case portion 50 is maintained.

[0051] In the present embodiment, as described above, the gas inside the housing 100 can reach the outside through the opening 53 of the case portion 50 and the opening 23 of the cover portion 20. Therefore, compared with the case where the gas reaches the outside through a slight gap in the vertical direction as in the above-mentioned Patent Document 1, the gas flow rate can be increased. Thereby, the internal pressure of the housing 100 can be quickly reduced.

[0052] Further, in the present embodiment, since the gap in the vertical direction is not used as a gas flow path, the amount of movement of the cover portion 20 in the vertical direction can be made smaller than that of the conventional pressure release valve. For this reason, the dimensions of the space allocated to the pressure release valve 10 in the vertical direction can be made smaller than those of the conventional pressure release valve. Thereby, the degree of freedom in layout design in the vertical direction can be increased.

[0053] It should be noted that various modifications can be made to the above-described embodiment. Hereinafter, modification examples will be described with reference to the drawings as necessary. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above-described embodiment will be used for the parts that can be configured in the same manner as in the above-described embodiment, and redundant descriptions will be omitted. Further, when it is clear that the operational effects obtained in the above-described embodiment can also be obtained in the modification example, the description thereof may be omitted.

[0054] In the above-described embodiment, an example is shown in which when the internal pressure of the housing 100 is less than the threshold value, the engagement between the first lock 26 of the cover portion 20 in the rotation direction D1 and the stopper 57 of the case portion 50 is maintained by the second biasing member 45. However, the means for maintaining the engagement between the cover portion 20 and the case portion 50 when the internal pressure of the housing 100 is less than the threshold value is not limited to the biasing force in the vertical direction by the second biasing member 45. For example, although not shown, the engagement between the cover portion 20 and the case portion 50 may be maintained by a mechanical engagement in the vertical direction. In this case, the mechanical engagement in the vertical direction is configured to be released when the internal pressure of the housing 100 becomes equal to or higher than the threshold value. The mechanical engagement is, for example, an engagement using claws.

Description of Symbols

[0055] 10 Pressure release valve 20 Cover part 23 Opening 24 Cylindrical part 26 First lock 27 Second lock 29 End lock 30 First sealing part 35 Second sealing part 40 First biasing member 45 Second biasing member 50 Case part 53 Opening 56 Shaft part 57 Stopper 58 Support part 100 Housing 103 Vent hole

Claims

1. A pressure relief valve that releases gas from a housing when the internal pressure of the gas inside the housing rises, including an opening, a case portion fixed to the surface of the housing, a cover portion supported by the case portion so as to be rotatable in a rotational direction parallel to the surface of the housing, and a first biasing member that biases the cover portion so that the cover portion rotates from a closed position to an open position in the rotational direction. In the closed position, the cover portion covers the opening of the case portion, and in the open position, the cover portion opens the opening of the case portion. The case portion includes a stopper that engages with the cover portion in the closed position. The pressure relief valve is configured such that when the internal pressure of the housing exceeds a threshold value, the engagement between the stopper and the cover portion is released.

2. The pressure relief valve according to claim 1, further comprising a second biasing member that biases the cover portion in a direction toward the case portion.

3. The pressure relief valve according to claim 1, wherein the cover portion includes a first lock that engages with the stopper of the case portion in the closed position.

4. The cover portion includes a cylindrical portion, the case portion includes a shaft portion that is inserted into the cylindrical portion and functions as a rotation axis in the rotational direction, and the first lock projects outward from the cylindrical portion.

5. The pressure relief valve according to claim 3 or 4, wherein the cover portion includes a second lock that engages with the stopper of the case portion in the open position.

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