JP2018037217A - Battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery pack in which a pressure release unit can be released at an appropriate timing.SOLUTION: When gas is released from a battery cell 8, an enclosure 2 is filled with the gas, and thereby internal pressure of the enclosure 2 increases. Consequently, a resin plate and a metal frame 23 deform elastically thus forming an opening. When the gas is released from the opening to the outside, internal pressure of the enclosure 2 is released. When firing occurs in the enclosure 2, the resin plate 22 melts to widen the opening area, thus dealing with rapid pressure rise. The frame 23 is provided with a release pressure adjustment section 100 for adjusting the release pressure of the pressure release unit 20. Consequently, the release pressure in the release pressure adjustment section 100 can be adjusted to an appropriate pressure, according to the specification of a battery pack 1, for example. More specifically, it can be adjusted so that the pressure release unit 20 releases pressure at an appropriate timing.SELECTED DRAWING: Figure 13

Description

  The present invention relates to a battery pack.

  As a conventional battery pack, for example, a technique described in Patent Document 1 is known. The battery pack described in Patent Literature 1 includes a plurality of batteries and a battery case in which these batteries are accommodated. A pressure release portion that opens as the internal pressure of the battery case increases is provided on the upper surface of the battery cover of the battery case. An opening is formed in a predetermined region on the upper surface of the battery cover. The pressure release portion includes a sealing plate that seals the opening, and a fastening member that fixes the sealing plate to the battery cover at the outer periphery of the opening. The whole area in the opening sealed with the sealing plate is a fragile part. The sealing plate is provided with a rupture portion composed of two slit-like through holes arranged in parallel at a predetermined interval across the opening. When gas is generated due to battery abnormalities, etc., and the internal pressure rises due to the gas filling the battery case, pressure is applied to the fragile part, and the sealing plate is deformed by this pressure, and the fracture part breaks. The opening is opened, and the gas is discharged from the opening to the outside.

JP 2011-198570 A

  Here, in the configuration including the pressure release unit as in the above-described conventional technology, the internal pressure is opened at a timing when the pressure rises to a predetermined pressure. However, the appropriate release pressure may be different depending on, for example, the specification of the battery pack. is there. Therefore, it has been demanded that the pressure release unit can be opened at an appropriate timing.

  Therefore, an object of the present invention is to provide a battery pack that can open the pressure release unit at an appropriate timing.

  The battery pack of one embodiment of the present invention includes a housing, battery cells housed in the housing, a pressure release unit that is attached to the upper surface of the housing and releases the internal pressure of the housing when the internal pressure of the housing increases. The pressure release unit includes a resin plate supported on the upper surface side of the housing, a metal frame disposed on the resin plate and constituting the opening window, and the frame through the resin plate. And a fixing part that fixes to the upper surface of the housing, and the frame is provided with an opening pressure adjusting part that adjusts the opening pressure of the pressure releasing unit.

  In such a battery pack, when the gas is released from the battery cell, the casing is filled with the gas, so that the internal pressure of the casing increases. For this reason, the resin plate and the metal frame are elastically deformed by the gas, and an opening is formed. And gas is discharge | released outside from the opening, and the internal pressure of a housing | casing is open | released. Moreover, when it ignites in a housing | casing, it can respond to a rapid pressure rise by melt | dissolving a resin plate and widening an opening area. Here, the frame body is provided with an open pressure adjusting unit for adjusting the open pressure of the pressure release unit. Therefore, for example, according to the specifications of the battery pack, the open pressure in the open pressure adjusting unit can be adjusted to an appropriate pressure. That is, the pressure release unit can be adjusted to be released at an appropriate timing. As described above, the pressure release unit can be opened at an appropriate timing.

  The frame body may include an outer peripheral member that surrounds the opening window portion from the outer peripheral side, and the open pressure adjusting portion may be configured by a beam member that is connected to the outer peripheral member and partitions the opening window portion. In this case, the ease of elastic deformation of the frame can be easily finely adjusted by partially increasing the strength of the frame by the beam member. Therefore, fine adjustment of the opening pressure by the opening pressure adjusting unit can be easily performed. Moreover, when a fall object falls with respect to a frame and a resin board, a resin board can be protected from a fall object with a beam member.

  The release pressure adjusting unit may be configured by a groove formed in the frame. In this case, the ease of elastic deformation of the frame can be easily finely adjusted by partially reducing the strength of the frame by the groove. Therefore, fine adjustment of the opening pressure by the opening pressure adjusting unit can be easily performed.

  The frame includes an outer peripheral member that surrounds the opening window portion from the outer peripheral side, and the groove portion extends between the inner peripheral end portion and the outer peripheral end portion of the outer peripheral member and opens at the inner peripheral end portion and the outer peripheral end portion. Good. In this case, even when water accumulates on the side of the opening window, water can be discharged to the outside from the outer peripheral end of the frame through the groove.

  The frame includes an outer peripheral member that surrounds the opening window portion from the outer peripheral side, and the release pressure adjusting portion is configured by a beam member that is connected to the outer peripheral member to partition the opening window portion, and a groove portion formed in the outer peripheral member. And the groove part may be formed in the position of a connection part with a beam member among outer peripheral members. In this case, when a beam member is provided in the opening window, the strength of the portion increases, and the other portion of the frame is easily opened by pressure. Therefore, by forming the groove at the position of the connecting portion with the beam member in the frame, the beam member portion can be partially opened easily. As a result, the difference in ease of opening depending on the position of the frame can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, when the internal pressure of a housing | casing raises rapidly, the momentum of the ejection of the gas from a housing | casing can be suppressed appropriately.

It is a perspective view which shows the external appearance of the battery pack which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view of the battery pack shown in FIG. FIG. 3 is a plan view of the battery module shown in FIG. 2. FIG. 2 is an enlarged perspective view of the pressure release unit shown in FIG. 1. FIG. 5 is an exploded perspective view of the pressure release unit shown in FIG. 4. FIG. 5 is a cross-sectional view of the pressure release unit shown in FIG. 4. FIG. 6 is a perspective view of the metal member shown in FIG. 5. It is a perspective view of the resin board shown by FIG. It is the schematic which shows the state which the resin of the resin board shown by FIG. 5 melt | dissolved, and was collected on the bottom part of the recessed part of a metal member. It is a detailed sectional view when the pressure release unit shown in FIG. 6 is viewed from another direction. It is a top view of a frame at the time of adopting a beam member as an open pressure adjustment part. It is a figure explaining the effect at the time of employ | adopting a beam member as an open pressure adjustment part. It is a perspective view of a frame at the time of adopting a slot as an open pressure adjustment part. It is sectional drawing explaining the effect at the time of employ | adopting a groove part as an open pressure adjustment part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing an appearance of a battery pack according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the battery pack shown in FIG. 1 and 2, the battery pack 1 of this embodiment includes a housing 2.

  The housing 2 includes a main body 3 having a substantially rectangular box shape, a projecting portion 4 disposed above the main body 3, and side walls 5 and 6 fixed to the main body 3 so as to sandwich the main body 3. And have. The side wall parts 5 and 6 extend upward from the upper surface 3 a of the main body part 3. The housing | casing 2 is formed with the metal (for example, iron). A plurality of battery modules 7 are accommodated in the main body 3. The battery module 7 is fixed to the inner wall surfaces of the side wall portions 5 and 6.

  As shown in FIG. 3, the battery module 7 includes a plurality of battery cells 8 arranged in one direction, and a restraining tool 9 that restrains the plurality of battery cells 8 in the arrangement direction of the battery cells 8. The battery cell 8 is held by the cell holder 10.

  The battery cell 8 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. Although not particularly illustrated, the battery cell 8 includes a rectangular parallelepiped case and an electrode assembly accommodated in the case. The electrode assembly has a structure in which a plurality of positive electrode sheets and a plurality of negative electrode sheets are alternately stacked via separators. The case is filled with an electrolytic solution.

  The battery cell 8 has a positive electrode terminal 11 and a negative electrode terminal 12. The positive electrode terminal 11 is provided on one end side of the upper surface of the battery cell 8 and is electrically connected to the positive electrode sheet of the electrode assembly. The negative electrode terminal 12 is provided on the other end side of the upper surface of the battery cell 8 and is electrically connected to the negative electrode sheet of the electrode assembly. The positive terminals 11 and the negative terminals 12 of the plurality of battery cells 8 are alternately arranged along the arrangement direction of the battery cells 8. That is, the two adjacent battery cells 8 are arranged such that the positive electrode terminal 11 and the negative electrode terminal 12 are opposite to each other. The positive electrode terminal 11 and the negative electrode terminal 12 of two adjacent battery cells 8 are electrically connected by a bus bar 13.

  A safety valve 14 is provided between the positive electrode terminal 11 and the negative electrode terminal 12 on the upper surface of the battery cell 8. The safety valve 14 releases gas existing inside the battery cell 8 when gas is generated inside the battery cell 8 and the internal pressure of the battery cell 8 rises to a specified pressure.

  The restraining tool 9 includes a pair of end plates 15 that sandwich the plurality of battery cells 8 in the arrangement direction of the battery cells 8, and the end plates 15 are fastened to each other, thereby arranging the battery cells 8 on the plurality of battery cells 8. A plurality of bolts 16 and nuts 17 for applying a direction restraining load are provided. The end plate 15 is made of metal (for example, iron). Between one end plate 15 and the battery cell 8, an elastic member 18 such as rubber for absorbing expansion of the battery cell 8 is disposed.

  Returning to FIGS. 1 and 2, a power supply system 19 including a harness and the like connected to each battery module 7 is accommodated in the protrusion 4. A charging connector (not shown) is disposed on one end side of the main body 3 in the longitudinal direction (X direction).

  A pressure release unit 20 that releases the internal pressure of the housing 2 when the internal pressure of the housing 2 rises is attached to the upper surface 3a on the other end side in the X direction of the main body 3 (opposite the charging connector with respect to the protruding portion 4). ing.

  FIG. 4 is an enlarged perspective view of the pressure release unit 20. FIG. 5 is an exploded perspective view of the pressure release unit 20. FIG. 6 is a cross-sectional view of the pressure release unit 20. 4 to 6, the pressure release unit 20 includes a metal member 21 supported on the upper surface 3 a of the main body 3 of the housing 2, a resin plate 22 disposed on the metal member 21, and the resin plate. And a metal frame 23 that constitutes the opening window 23a.

  As shown in FIG. 5, two rectangular opening windows 24 arranged side by side in the longitudinal direction (X direction) of the housing 2 are provided on the upper surface 3 a of the main body 3. Between each opening window part 24 in the upper surface 3a of the main-body part 3, the several screw hole 25 (only one is shown in FIG. 5) by which the internal thread was cut is provided. A screw 40 described later is screwed into the screw hole 25. The screw holes 25 are arranged in a state of being alternately shifted in the X direction along the width direction (Y direction) of the housing 2. Note that the width direction of the housing 2 is a direction perpendicular to the longitudinal direction of the housing 2.

  The metal member 21 is made of, for example, iron. As shown also in FIG. 7, the metal member 21 is erected on the upper side (resin plate 22 side) from the edge of the two bottom plate portions 26 and the bottom plate portion 26, and cooperates with the bottom plate portion 26. Then, two rectangular side plate portions 28 that define a concave portion 27 having a rectangular cross section, a connection portion 29 that connects the upper ends of the side plate portions 28, and an upper end of each side plate portion 28 and an outer side from the connection portion 29. It has a rectangular flange portion 30 that is provided so as to project laterally and is placed on the upper surface 3 a of the main body portion 3 of the housing 2.

  The bottom plate portion 26 is arranged so that the gas released from the safety valve 14 of each battery cell 8 is hit. The bottom surface of the recess 27 has a planar shape. The side plate portion 28 has a pair of side walls 28a facing the width direction (Y direction) of the housing 2 and a pair of side walls 28b facing the longitudinal direction (X direction) of the housing 2. The side wall 28 a extends in parallel with the direction in which the two recesses 27 are juxtaposed.

  A plurality of circular holes 31 having a circular cross section are provided in the side wall 28a. The holes 31 are regularly arranged in a plurality of rows (for example, two rows). The side wall 28a is configured, for example, as a punching metal. Note that the holes 31 may be arranged in one row, or may be arranged in three or more rows. Moreover, the hole part 31 may be arranged at random.

  The connecting portion 29 is provided with a plurality of circular holes 32 having a circular cross section through which a shaft portion 40a of a screw 40 described later passes. The fool holes 32 are arranged in a state of being alternately shifted in the X direction along the Y direction. The diameter of the fool hole 32 is larger than the diameter of the shaft portion 40 a of the screw 40.

  As shown in FIG. 8, the resin plate 22 has a rectangular shape in plan view. The resin plate 22 is formed of a resin such as ABS resin (acrylonitrile butadiene styrene copolymer synthetic resin).

  In the central portion of the resin plate 22 in the X direction, a plurality of hole holes 33 through which a shaft portion 40a of a screw 40 described later passes are provided. The fool holes 33 are arranged in a state of being alternately shifted in the X direction along the Y direction. A metal collar 34 is fitted in the fool hole 33. The diameter of the fool hole 33 is larger than the diameter of the shaft portion 40 a of the screw 40.

As shown in FIG. 9, the resin plate 22 is provided on the side plate portion 28 when the resin S of the resin plate 22 is melted and accumulated at the bottom of the concave portion 27 of the metal member 21 by ignition of the battery pack 1 or the like. The hole 31 has a volume such that the resin S is not completely blocked. That is, the thickness d ₂ of the resin S when the resin S of the resin plate 22 is melted and collected at the bottom of the recess 27 is equal to or less than the distance d ₁ from the bottom surface of the recess 27 to the hole 31. In addition, the plate | board thickness of the resin board 22 at the time of normal temperature (20 degreeC) is about 3 mm, for example.

  The frame body 23 is a member that reinforces the strength of the resin plate 22 and is made of, for example, iron. The frame body 23 includes a rectangular outer frame 35 in plan view, an extending portion 36 extending in the Y direction so as to connect the X direction center portions of the outer frame 35, and the Y direction center portion of the outer frame 35. It has a pair of beam members 37 extending in the X direction so as to be connected to the central portion in the Y direction of the existing portion 36. Accordingly, the frame body 23 constitutes four opening window portions 23a. A more detailed description of the frame body 23 will be described later.

  The extension portion 36 is provided with a plurality of holes 38 through which a shaft portion 40a of a screw 40 described later passes. The fool holes 38 are arranged in a state of being alternately displaced in the X direction along the Y direction. The diameter of the fool hole 38 is larger than the diameter of the shaft portion 40 a of the screw 40.

  Further, the pressure release unit 20 has a fixing portion 39 that fixes the frame body 23 to the upper surface 3 a of the main body portion 3 of the housing 2 via the resin plate 22 and the metal member 21. The fixing portion 39 mainly has a plurality of screws 40 that are screwed into the respective screw holes 25 provided on the upper surface 3 a of the main body portion 3. Also, a plurality of fool holes 32 provided in the connecting portion 29 of the metal member 21, a plurality of fool holes 33 provided in the resin plate 22, and a plurality of fool holes provided in the extending portion 36 of the frame body 23. 38 constitutes a part of the fixing portion 39. The shaft portion 40 a of the plurality of screws 40 is screwed into the screw hole 25 through the fool holes 38, 33, 32, whereby the frame body 23 is fixed to the upper surface 3 a of the main body portion 3 through the resin plate 22 and the metal member 21. .

  At this time, the fixing portion 39 fixes the central portion in the X direction of the frame body 23 to the upper surface 3 a of the main body portion 3 via the resin plate 22 and the metal member 21. For this reason, two concave portions 27 of the metal member 21 are arranged side by side so as to sandwich the fixing portion 39.

  Further, as shown in FIG. 10, the pressure release unit 20 includes a rectangular annular seal member 41 (in FIGS. 5 and 6) disposed between the upper surface 3 a of the main body 3 of the housing 2 and the resin plate 22. (Omitted). The seal member 41 is made of rubber or the like. The flange portion 30 of the metal member 21 also has a function of regulating the compression rate of the seal member 41. Therefore, the thickness of the seal member 41 is set to the thickness of the flange portion 30. A gap is formed between the inner wall surface 3 b of the main body 3 of the housing 2 and the side wall 28 a of the side plate 28 of the metal member 21.

  In the battery pack 1 configured as described above, when the gas generated in the battery cell 8 is released from the safety valve 14, the casing 2 is filled with the gas, and thus the internal pressure of the casing 2 increases. At this time, the gas released from the safety valve 14 strikes the bottom plate portion 26 of the metal member 21 and is diffused inside the housing 2. Then, the gas wraps around the gap between the inner wall surface 3b of the main body 3 of the housing 2 and the side wall 28a of the side plate 28 of the metal member 21, passes through each hole 31 provided in the side wall 28a, and passes through the hole 31. It enters into the recess 27 of the member 21. For this reason, both sides of the fixing portion 39 in the resin plate 22 and the frame body 23 are elastically changed to the upper side of the housing 2 by the gas, and an opening is formed. And the internal pressure of the housing | casing 2 is open | released when gas is discharge | released outside from the opening.

  Further, when the battery pack 1 is ignited for some reason, the internal pressure of the housing 2 rapidly increases. At this time, since the resin S of the resin plate 22 melts and melts into the concave portion 27 of the metal member 21, the opening window portion 23a of the frame body 23 opens. And the internal pressure of the housing | casing 2 is open | released when gas is discharge | released outside from the opening.

  As described above, according to the present embodiment, even if the internal pressure of the housing 2 suddenly rises, the resin S of the resin plate 22 dissolves, so that the opening window portion 23a of the frame body 23 opens. The opening area of the pressure release unit 20 is larger than when the 22 and the frame body 23 are elastically deformed. Thereby, the momentum of the ejection of the gas from the inside of the housing | casing 2 is suppressed. Therefore, the flow rate of the gas released to the outside of the battery pack 1 can be reduced. Moreover, since the opening area of the pressure release unit 20 is increased, the housing 2 can be prevented from being damaged.

  Further, a side plate portion 28 having a plurality of hole portions 31 is disposed in a path through which the gas flows in the housing 2. Therefore, even if the internal components of the battery pack 1 flow in the housing 2 due to the gas flow, the internal components hit the side plate portion 28 having the plurality of holes 31. For this reason, even if the opening area of the pressure release unit 20 is increased, the internal components of the battery pack 1 are prevented from being scattered outside.

  In the present embodiment, the seal member 41 is disposed between the upper surface 3 a of the housing 2 and the resin plate 22, and the flange portion 30 of the metal member 21 is placed on the upper surface 3 a of the housing 2. The For this reason, the flange portion 30 also serves as a function of regulating the compression rate of the seal member 41. Accordingly, it is not necessary to separately provide a component such as a spacer that regulates the compression rate of the seal member 41. Therefore, the number of components of the battery pack 1 can be reduced, and the component cost can be reduced.

  In the present embodiment, the fixing portion 39 fixes the central portion of the frame body 23 to the upper surface 3 a of the housing 2 via the resin plate 22 and the metal member 21. Therefore, the resin plate 22 and the frame body 23 are elastically deformed to form two openings with the fixing portion 39 interposed therebetween, and the frame body 23, the resin plate 22, and the metal member 21 are connected to the upper surface 3 a of the housing 2. Can be fixed in good balance.

  Further, in the present embodiment, the plurality of hole portions 31 are respectively provided in the pair of side walls 28 a facing the side plate portion 28. Therefore, since it is not necessary to perform the process of forming the hole 31 in the entire side plate portion 28, the manufacturing cost of the metal member 21 can be suppressed.

  In the present embodiment, the resin plate 22 has a volume that does not block the hole 31 when the resin S of the resin plate 22 is melted and collected at the bottom of the recess 27 of the metal member 21. . For this reason, when the internal pressure of the housing | casing 2 rises rapidly, the raise of the further internal pressure by the hole 31 being plugged up with resin S can be prevented reliably.

  In this embodiment, since the frame body 23 has the beam member 37, the frame body 23 is reinforced, and an impact from the outside is hardly applied to the resin plate 22.

  Next, with reference to FIGS. 11 to 14, the open pressure adjustment unit 100 of the battery pack 1 according to the present embodiment will be described. In the frame 23 of the pressure release unit 20 of the battery pack 1 according to the present embodiment, an open pressure adjustment unit 100 that adjusts the open pressure of the pressure release unit 20 is provided. Here, the “opening pressure” means that the internal pressure of the housing 2 increases, and both sides of the fixing portion 39 of the resin plate 22 and the frame body 23 are elastically changed upward by the gas to form an opening. When it is done, it shall be the internal pressure. The optimum value of the opening pressure may be slightly different depending on the specifications of the battery pack 1 and the like. The open pressure adjusting unit 100 is configured to finely adjust the open pressure according to such a slight difference. That is, the release pressure adjusting unit 100 adjusts the release pressure by changing the premise structure such as the shape, length, and thickness of the frame body 23 (when the premise configuration is changed, the open pressure changes greatly). Instead, the premise structure is the same, but fine adjustment of the opening pressure is performed. In the present embodiment, the premise configuration is the shape, width, length, thickness, and the like of the outer peripheral member 53 and the extending portion 36.

  The opening pressure adjusting unit 100 is configured by a beam member 37 that is connected to the outer peripheral member 53 of the frame body 23 and partitions the opening window 23a. Specifically, the outer peripheral member 53 is a rectangular annular member that surrounds the opening window 23a from the outer peripheral side. The outer peripheral member 53 includes side portions 54A and 54B that face in the Y-axis direction and side portions 54C and 54D that face in the X-axis direction. The central positions of the side portions 54A and 54B in the X-axis direction are connected by an extending portion 36 that extends straight in the Y-axis direction. The central positions of the side portions 54C and 54D in the Y-axis direction are connected by a beam member 37 that extends straight in the X-axis direction. The beam member 37 is partitioned into two opening window portions 23 a by extending between the side portion 54 </ b> C and the extending portion 36. The beam member 37 is partitioned into two opening window portions 23a by extending between the side portion 54D and the extending portion 36. The thickness of the beam member 37 may be the same as that of the outer peripheral member 53 or may be smaller than that of the outer peripheral member 53.

  The beam member 37 supports the side portion 54D and the side portion 54C of the outer peripheral member 53, whereby the strength of the frame body 23 is improved. For example, on the premise that the size, width, thickness, etc. of the outer peripheral member 53 and the extending portion 36 are unchanged, by providing the beam member 37, the strength of the frame body 23 is improved and it is difficult to be elastically deformed. Thus, fine adjustment can be made so that the release pressure becomes high. Further, the opening pressure can be finely adjusted by adjusting the width and thickness of the beam member 37. The beam members 37 may be provided with a plurality of beam members 37 extending in the X-axis direction at intervals in the Y-axis direction, as indicated by phantom lines in the figure. When there are a plurality of beam members 37 as described above, a part of the beam members 37 may be cut in order to facilitate elastic deformation of the frame body 23. The beam member 37 may extend straight in the Y-axis direction. Further, the beam member 37 may extend in an oblique direction.

  Further, as shown in FIG. 13, the release pressure adjusting unit 100 may be configured by a groove 51 formed in the frame body 23. FIG. 13 shows the configuration of the lower surface side of the frame body 23. As shown in FIG. 13A, a groove 51 is formed on the lower surface of each side 54 </ b> A to 54 </ b> D of the outer peripheral member 53. The groove portion 51 extends between the inner peripheral end portion 53a and the outer peripheral end portion 53b of the outer peripheral member 53, and opens at the inner peripheral end portion 53a and the outer peripheral end portion 53b. Although the cross-sectional shape of the groove part 51 is not specifically limited, For example, as shown in FIG.14 (b), it may be a rectangular shape.

  In the case of having such a configuration, as shown in FIG. 14A, the internal space of the opening window portion 23 a of the frame body 23 and the external space on the outer peripheral side from the frame body 23 are communicated with each other via the groove portion 51. The Here, a concave portion is formed by the inner peripheral end portion 53 a of the outer peripheral member 53 and the resin plate 22. In the battery pack 1, water W may accumulate in the recesses by cleaning the built-in device or causing condensation. In this embodiment, since the groove part 51 which connects the internal space of a recessed part and an external space is formed in the lower surface (namely, surface which contacts the resin board 22) of the outer peripheral member 53, the water W passes through the said groove part 51. It is discharged to the external space. In addition, the depth of the groove part 51 ensures the depth of the grade which water does not flow by the influence of surface tension. Moreover, drainage can be improved by increasing the number of the groove parts 51. However, it is preferable to prevent the strength of the frame body 23 from being excessively lowered by increasing the depth of the groove 51 or increasing the number of the grooves 51.

  Returning to FIG. 13A, an example of the formation position of the groove 51 will be described. As shown to Fig.13 (a), the groove part 51 is formed in the center position of side part 54C, 54D. Further, the groove 51 is formed in the vicinity of the boundary position between the opening window portion 23a and the extending portion 36 in the side portions 54A and 54B. The groove 51 communicates with the opening window 23a at the boundary position between the opening window 23a and the extension 36. As described above, the groove 51 is formed in each of the four side portions 54A to 54B. As described above, the grooves 51 are formed in the four directions, so that the water W can be discharged from any direction even if the frame body 23 is inclined due to the distortion. Further, the extending portion 36 fixed with screws is disposed at a lower position by sinking downward as compared with other portions in the frame body 23. Accordingly, the water W is most easily collected at a position near the extending portion 36 in the internal space of the opening window portion 23a. Therefore, the drainage can be enhanced by forming the groove 51 in the vicinity of the extending portion 36. In addition, the width dimension of the groove part 51 formed in each position may be the same. However, the groove 51 formed in the vicinity of the extending portion 36 close to the screw fastening position has a great influence on the ease of elastic deformation of the frame body 23. Therefore, the frame body 23 may be easily elastically deformed by making the width dimension of the groove 51 in the portion larger than the groove 51 in the other portion. Or you may suppress that it becomes easy to carry out elastic deformation too much by making the width dimension of the groove part 51 in the said part smaller than the groove part 51 of another part.

  Further, as shown in FIG. 13B, the opening pressure adjusting unit 100 may be configured by combining the beam member 37 and the groove 51. When the beam member 37 is provided, the groove 51 may be formed at the position of the outer peripheral member 53 where the beam member 37 is connected. In the example of FIG. 13B, the groove 51 extends from the opening windows 23a on both sides in the Y-axis direction, merges in the vicinity of the center position in the width direction of the beam member 37, and extends to the outer peripheral end 53b. ing. However, the present invention is not limited to this configuration, and may extend to the outer peripheral end portion 53b independently from each of the opening window portions 23a on both sides in the Y-axis direction. In this case, the pair of groove portions 51 may extend in a form in which both end portions in the width direction of the beam member 37 are extended. Such a structure is a structure in which the beam member 37 is provided at a position between the pair of groove portions 51 of the side portions 54C and 54D in FIG.

  Next, functions and effects of the battery pack 1 according to the present embodiment will be described.

  In the battery pack 1 according to the present embodiment, when the gas is released from the battery cells 8, the casing 2 is filled with the gas, so that the internal pressure of the casing 2 increases. For this reason, the resin plate and the metal frame 23 are elastically deformed by the gas, and an opening is formed. And the internal pressure of the housing | casing 2 is open | released when gas is discharge | released outside from the opening. Moreover, when it ignites in the housing | casing 2, it can respond to a rapid pressure rise by melt | dissolving the resin board 22 and widening an opening area. Here, the frame body 23 is provided with an opening pressure adjusting unit 100 that adjusts the opening pressure of the pressure releasing unit 20. Therefore, for example, according to the specifications of the battery pack 1 and the like, the open pressure in the open pressure adjusting unit 100 can be adjusted to an appropriate pressure. That is, the pressure release unit 20 can be adjusted to be released at an appropriate timing. As described above, the pressure release unit 20 can be opened at an appropriate timing.

  The frame body 23 includes an outer peripheral member 53 that surrounds the opening window portion 23a from the outer peripheral side, and the open pressure adjusting portion 100 may be configured by a beam member 37 that is connected to the outer peripheral member 53 and partitions the opening window portion 23a. . In this case, by partially increasing the strength of the frame body 23 by the beam member 37, the ease of elastic deformation of the frame body 23 can be easily finely adjusted. Therefore, fine adjustment of the open pressure by the open pressure adjusting unit 100 can be easily performed. Moreover, when a fall object falls with respect to the frame 23 and the resin board 22, the resin board 22 can be protected from a fall object by the beam member 37. FIG. Specifically, as shown in FIG. 12B, when the beam member 37 is not provided and the fallen object TL such as a tool falls to the pressure release unit 20, the fallen object TL is transferred to the resin plate 22. There is a possibility of colliding directly with. On the other hand, as shown in FIG. 12A, when the beam member 37 is provided, when the fallen object TL falls to the pressure release unit 20, it collides with the beam member 37 and directly onto the resin plate 22. There are cases where collision can be avoided.

  The release pressure adjusting unit 100 may be configured by a groove 51 formed in the frame body 23. In this case, the ease of elastic deformation of the frame body 23 can be easily finely adjusted by partially reducing the strength of the frame body 23 by the groove 51. Therefore, fine adjustment of the open pressure by the open pressure adjusting unit 100 can be easily performed.

  The frame 23 includes an outer peripheral member 53 that surrounds the opening window portion 23a from the outer peripheral side, and the groove 51 extends between the inner peripheral end portion 53a and the outer peripheral end portion 53b of the outer peripheral member 53, and the inner peripheral end portion 53a and You may open at the outer periphery edge part 53b. In this case, even when water has accumulated on the opening window 23a side, water can be discharged from the outer peripheral end 53b of the frame 23 to the outside through the groove 51.

  The frame body 23 includes an outer peripheral member 53 that surrounds the opening window portion 23 a from the outer peripheral side, and the release pressure adjusting unit 100 is connected to the outer peripheral member 53 to define the opening window portion 23 a and the outer peripheral member 53. The groove 51 may be formed at the position of the connecting portion of the outer circumferential member 53 with the beam member 37. In this case, when the beam member 37 is provided in the opening window portion 23a, the strength of the portion increases, and other portions of the frame body 23 are easily opened by pressure. Therefore, by forming the groove portion 51 at the position of the connecting portion with the beam member 37 in the frame body 23, the portion of the beam member 37 can be easily opened partially. Thereby, the difference of the easiness of opening by the position of the frame 23 can be reduced.

  The present invention is not limited to the above embodiment.

  For example, the groove 51 extends straight from the inner peripheral end 53a of the outer peripheral member 53 toward the outer peripheral end 53b, but may be extended in any shape as long as the release pressure can be adjusted. For example, although the effect which drains water is not acquired, you may form the groove part extended along each side part 54A-54D. Further, the width of the groove 51 may be wider than that shown in FIG.

  Moreover, in the said embodiment, although the bottom face of the recessed part 27 of the metal member 21 is planar, the shape of the recessed part 27 is not restricted to it in particular, For example, it is a cross section which becomes deep toward the center part of the recessed part 27 V shape etc. may be sufficient.

  In the above embodiment, the resin plate 22 has a volume that does not completely block the hole 31 when the resin S of the resin plate 22 is dissolved and collected at the bottom of the recess 27. The form is not particularly limited. For example, the resin plate 22 has a volume that slightly blocks the hole 31 (for example, about several percent or less of the opening area of the hole 31) when the resin S of the resin plate 22 dissolves and accumulates at the bottom of the recess 27. You may have.

  Furthermore, in the said embodiment, although the fixing | fixed part 39 fixes the center part of the frame 23 to the upper surface 3a of the housing | casing 2 via the resin plate 22 and the metal member 21, the frame 23 by the fixing | fixed part 39 is fixed. The fixing location is not particularly limited to this, and may be a position shifted from the central portion of the frame body 23 in the longitudinal direction (X direction) of the housing 2.

  Moreover, in the said embodiment, although the housing | casing 2 has the main-body part 3 which has a substantially rectangular box shape, and the protrusion part 4 arrange | positioned above this main-body part 3, as a housing | casing 2, In particular, the structure is not limited thereto, and may have a substantially rectangular box shape having no protrusion.

  DESCRIPTION OF SYMBOLS 1 ... Battery pack, 2 ... Housing | casing, 8 ... Battery cell, 20 ... Pressure release unit, 22 ... Resin board, 23 ... Frame, 23a ... Opening window part, 37 ... Beam member, 51 ... Groove part, 53 ... Outer periphery member 53a ... inner peripheral end portion, 53b ... outer peripheral end portion, 100 ... open pressure adjusting portion.

Claims (5)

A housing,
Battery cells housed in the housing;
A pressure release unit that is attached to the upper surface of the housing and releases the internal pressure of the housing when the internal pressure of the housing increases.
The pressure relief unit is
A resin plate supported on the upper surface side of the housing;
A metal frame which is disposed on the resin plate and forms an opening window;
A fixing portion for fixing the frame body to the upper surface of the housing via the resin plate,
The battery pack according to claim 1, wherein an opening pressure adjusting unit that adjusts an opening pressure of the pressure releasing unit is provided on the frame body. The frame includes an outer peripheral member that surrounds the opening window from the outer peripheral side,
2. The battery pack according to claim 1, wherein the open pressure adjusting portion is configured by a beam member that is connected to the outer peripheral member and partitions the opening window portion.   3. The battery pack according to claim 1, wherein the release pressure adjusting unit is configured by a groove formed in the frame. 4. The frame includes an outer peripheral member that surrounds the opening window from the outer peripheral side,
The battery pack according to claim 3, wherein the groove portion extends between an inner peripheral end portion and an outer peripheral end portion of the outer peripheral member, and is open at the inner peripheral end portion and the outer peripheral end portion. . The frame includes an outer peripheral member that surrounds the opening window from the outer peripheral side,
The open pressure adjusting portion is constituted by a beam member that is connected to the outer peripheral member and partitions the opening window portion, and a groove portion formed in the outer peripheral member,
2. The battery pack according to claim 1, wherein the groove portion is formed at a position of a connection portion between the outer circumferential member and the beam member.

Images