JP2020071945A - Power storage device - Google Patents

Abstract

To provide a power storage device including an operation mechanism operating with a second working pressure higher than a first working pressure with which a relief valve operates, in which operation of the operation mechanism is not blocked, while securing function of the relief valve.SOLUTION: A relief valve includes a housing part 40 in which a housing space 48 is formed, an elastic sheet 41 placed in the housing space 48, a metal plate 42 and a porous sheet. In the housing part 40, a first continuous hole 49 communicating with the housing space 48 and a housing case 3, and a second continuous hole 47 communicating with the outside of the housing case 3 and the housing space 48 are formed. The elastic sheet 41, the metal plate 42 and the porous sheet are laminated sequentially in the lamination direction from the first continuous hole 49 toward the second continuous hole 47 in the housing space 48.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a power storage device.

  Conventionally, in a power storage device, when the internal pressure in the power storage device rises, various proposals have been made for a power storage device including a relief valve that exhausts gas in the power storage device to the outside to stabilize the internal pressure in the power storage device. There is.

  For example, the power storage device described in Japanese Patent Application Laid-Open No. 2003-272589 includes an outer can that houses an electrode body and the like, a sealing plate that is provided on the outer can, and a relief valve that is provided on the sealing plate. ing.

  The outer can includes a can body having an opening formed therein, and a sealing plate that closes the opening of the can body. An exhaust hole communicating with the inside of the outer can is formed in the sealing plate, and the sealing plate is formed so as to be recessed toward the inside of the outer can.

  The relief valve includes a positive electrode cap, a spring, and a valve body. The positive electrode cap is attached to the sealing plate from the outside and is formed so as to project outward. An accommodation space for accommodating the spring and the valve body is formed between the positive electrode cap and the sealing plate. The positive electrode cap has a communication hole that communicates the accommodation space with an external space outside the power storage device.

  The valve body is provided so as to close the exhaust port, and the spring urges the valve body to press it against the exhaust port.

  The power storage device described in JP 2006-125559 A includes a capacitor, an aluminum laminate bag that houses the capacitor, and a gas vent valve provided in the aluminum laminate bag.

  The degassing valve includes a resin cup, a valve membrane provided in the cup, and a synthetic fiber material. A plurality of ventilation holes are formed on the surface of the aluminum laminate bag. The cup is arranged on the inner surface side of the aluminum laminated bag, and the cup and the aluminum laminated bag form a housing space for housing the valve membrane and the synthetic fiber material.

  The cup has a bottom hole that communicates the accommodation space with the inside of the aluminum laminate bag, and the cup is arranged so that the ventilation hole of the aluminum laminate bag and the accommodation space communicate with each other.

  The valve leaflet is arranged so as to close the bottom hole formed in the cup, and the valve leaflet is formed of a rubber sheet. The synthetic fibrous material is arranged between the valve body and the inner surface of the aluminum laminate bag, and is provided so as to close the ventilation hole.

JP, 2003-272589, A JP, 2006-125559, A

  In recent years, for example, a power storage device used as a battery for running a vehicle has become widespread. Such a power storage device includes an electrode body, a housing case for housing the electrode body, an external terminal provided on a lid of the housing case, and the like.

  In such a power storage device, the housing case is provided with, for example, a current interruption device such as a CID (Current Interrupt Device) and an explosion-proof valve.

  The CID is, for example, a mechanism that shuts off the electrical connection between the external terminal and the electrode body when the internal pressure in the housing case becomes extremely high.

  The explosion-proof valve is formed on the lid of the housing case or the like, and is formed in a thinner film than other portions. Then, when the internal pressure in the housing case becomes very high, the explosion-proof valve breaks. As a result, a very high internal pressure in the housing case is reduced.

  The CID and the explosion-proof valve are mechanisms that operate to suppress the phenomenon when the internal pressure in the housing case becomes extremely high. Therefore, the CID and the explosion-proof valve need to operate reliably when the internal pressure in the housing case becomes very high. The operating pressure of the CID and explosion-proof valve is generally set higher than the operating pressure of the relief valve.

  On the other hand, for example, in the relief valve described in Japanese Patent Application Laid-Open No. 2003-272589 and the gas vent valve described in Japanese Patent Application Laid-Open No. 2006-125559, as soon as the internal pressure of the outer can or the aluminum laminated bag rises, , The internal gas will be exhausted to the outside.

  As a result, even when the internal pressure in the outer can or the aluminum laminated bag is extremely high, the relief valve is driven and the internal pressure is unlikely to be high, and the CID or the explosion-proof valve is hard to operate. Is becoming

  The present disclosure has been made in view of the above problems, and an object thereof is to provide a power storage device including an operating mechanism that operates at a second operating pressure higher than a first operating pressure at which a relief valve operates. An object of the present invention is to provide a power storage device that does not hinder the operation of the operating mechanism while ensuring the function of the relief valve.

  The power storage device according to the present disclosure is provided in an electrode body, a housing case that houses the electrode body, and the housing case. When the internal pressure in the housing case becomes equal to or higher than the first pressure, the gas in the housing case is exhausted to the outside. The relief valve includes: a relief valve; and an actuating mechanism that operates when the inner pressure in the housing case reaches a second pressure higher than the first pressure. The relief valve includes a housing part having a housing space formed therein, and a housing part inside the housing space. A first communication hole including the arranged elastic body, a metal plate and a porous sheet, and a second communication hole that communicates between the accommodation space and the inside of the accommodation case and the outside of the accommodation case and the accommodation space in the accommodation section. And the elastic body, the metal plate, and the porous sheet are sequentially stacked in the accommodating space in the stacking direction from the first communication hole to the second communication hole. 1 communication Including a first main surface located on the side and a second main surface located on the side opposite to the first main surface, the elastic body biases the metal plate toward the porous sheet in the stacking direction, An exposed portion exposed from the elastic body is formed on at least a part of the first main surface of the metal plate, and internal pressure in the housing case is applied to the exposed portion of the metal plate through the first communication hole. The porous sheet closes the second communication hole by the biasing force applied from the elastic body applied through the metal plate, and when the internal pressure in the housing case becomes higher than the first pressure, A gap is formed between the metal plates, and the gas in the containing case is exhausted to the outside of the containing case through the gap, the porous sheet, and the second communication hole.

  According to the above relief valve, when the internal pressure in the housing case becomes equal to or higher than the first pressure, the metal plate floats up from the elastic body, and a gap is formed between the metal plate and the elastic body.

  When the gap is formed, the gas in the storage case enters the storage space through the first communication hole. The gas that has entered the accommodation space passes through the porous sheet and is exhausted to the outside through the second communication hole. At this time, since the gas passes through the porous sheet, it is possible to prevent the gas from being excessively exhausted from the second communication hole.

  As a result, it is possible to prevent the internal pressure in the housing case from becoming difficult to rise. Then, when an abnormality occurs in the housing case, the internal pressure in the housing case can be raised to the second pressure, and the actuating mechanism can be driven.

  According to the power storage device of the present disclosure, in a power storage device including an operating mechanism that operates at a second operating pressure that is higher than a first operating pressure at which a relief valve operates, while ensuring the function of the relief valve, The inhibition of the operation can be suppressed.

FIG. 3 is a cross-sectional perspective view showing power storage device 1 according to the present embodiment. It is a cross-sectional perspective view which shows the structure of the electric current interruption mechanism 8 and its circumference. FIG. 3 is a sectional perspective view showing a relief valve 10. FIG. 3 is a sectional view showing a relief valve 10. FIG. 7 is a cross-sectional view showing the relief valve 10 when the internal pressure in the housing case 3 rises to a predetermined pressure P1. FIG. 3 is a cross-sectional view showing a relief valve 10A of power storage device 1A. FIG. 7 is a sectional view showing a relief valve 10B according to a second embodiment. FIG. 9 is a cross-sectional view showing a relief valve 10C according to a third embodiment. It is sectional drawing which shows the relief valve 10D. It is a graph which shows the internal pressure situation etc. in the storage case 3 in which the relief valve 10 which concerns on an Example was provided.

  The relief valve according to the present embodiment will be described with reference to FIGS. 1 to 10. Of the configurations shown in FIGS. 1 to 10, the same or substantially the same configurations are denoted by the same reference numerals, and duplicated description will be omitted. Note that, in the structure shown in the embodiment, a structure corresponding to a structure described in a claim may be described in parentheses together with a structure in the claim.

(Embodiment 1)
FIG. 1 is a cross-sectional perspective view showing a power storage device 1 according to the present embodiment. The power storage device 1 includes an electrode body 2, a housing case 3, a positive electrode terminal 4, a negative electrode terminal 5, a positive electrode current collector plate 6, a negative electrode current collector plate 7, a current interruption mechanism 8, and an electrolyte solution 9. A relief valve 10 and an opening valve 11 are provided.

  The electrode body 2 includes a plurality of positive electrode sheets 13, a plurality of separators 14, and a plurality of negative electrode sheets 15. The electrode body 2 is formed by sequentially stacking the positive electrode sheet 13, the separator 14, and the negative electrode sheet 15.

  The electrode body 2 includes a positive electrode 16 formed at one end in the width direction W and a negative electrode 17 formed at the other end in the width direction W.

  The storage case 3 includes a storage case 20 and a lid 21. The housing case 3 is made of aluminum or an aluminum alloy.

  The housing case 20 opens upward, and the lid 21 closes the opening of the housing case 20. The positive electrode terminal 4 and the negative electrode terminal 5 are formed on the upper surface of the lid 21. The positive electrode terminal 4 and the negative electrode terminal 5 are arranged at intervals in the width direction W.

  The release valve 11 is formed on the upper surface of the lid 21. The thickness of the portion of the lid 21 where the release valve 11 is located is formed thinner than the thickness of the other portions of the lid 21.

  The relief valve 10 is formed on the upper surface of the lid 21. The detailed structure of the relief valve 10 will be described later.

  The positive electrode current collector plate 6 connects the positive electrode 16 of the electrode body 2 and the positive electrode terminal 4. The negative electrode current collector plate 7 connects the negative electrode 17 of the electrode body 2 and the negative electrode terminal 5.

  The current cutoff mechanism 8 is provided between the positive electrode current collector plate 6 and the positive electrode terminal 4, and the current cutoff mechanism 8 is arranged on the lower surface side of the lid 21.

  FIG. 2 is a cross-sectional perspective view showing the configuration of the current interruption mechanism 8 and its surroundings. The positive electrode terminal 4 includes a resin member 25, a connection plate 26, and a terminal 27.

  The resin member 25 is provided on the upper surface of the lid 21. The connection plate 26 is provided on the upper surface of the resin member 25. The terminal 27 is provided on the upper surface of the resin member 25, and is formed so as to penetrate from the lower surface side of the connection plate 26 toward the upper surface.

  The positive electrode current collector plate 6 includes a leg portion 30 and a top plate portion 31. The leg portion 30 is welded to the positive electrode 16 of the electrode body 2. The top plate portion 31 is formed on the upper ends of the leg portions 30. The top plate portion 31 is formed with a through hole 32 penetrating from the top surface to the bottom surface of the top plate portion 31.

The current interruption mechanism 8 includes a reversal plate 33, an engagement pin 34, and an insulating member 35.
The insulating member 35 is arranged on the lower surface of the lid 21. The engagement pin 34 includes a tubular portion 36 and a dish portion 37. The plate portion 37 is arranged on the lower surface side of the insulating member 35.

  The tubular portion 36 is formed in a tubular shape. The tubular portion 36 is formed so as to project upward from the upper surface of the dish portion 37, and the tubular portion 36 penetrates the insulating member 35, the lid 21, the resin member 25, and the connection plate 26. .. The upper end of the tubular portion 36 is formed so as to expand its diameter, and the upper end of the tubular portion 36 engages with the upper surface of the connecting plate 26. By engaging the upper end of the tubular portion 36 with the connection plate 26, the positive electrode terminal 4 and the insulating member 35 are fixed to the lid 21 by the dish portion 37 and the upper end of the tubular portion 36.

  The hollow portion of the tubular portion 36 reaches the upper end of the tubular portion 36. The space between the reversing plate 33 and the dish portion 37 communicates with the hollow portion of the tubular portion 36, and the space between the reversing plate 33 and the dish portion 37 is at atmospheric pressure.

  The reversal plate 33 is elastically deformable and is arranged on the upper surface side of the top plate portion 31. The outer peripheral edge of the reversal plate 33 is welded to the dish 37. In the state shown in FIG. 8, the center of the reversing plate 33 extends downward, and the center of the reversing plate 33 is welded to the opening edge of the through hole 32.

  Here, the positive electrode current collector plate 6 is electrically connected to the positive electrode 16 of the electrode body 2, and the positive electrode current collector plate 6 is electrically connected to the reversal plate 33. The reversal plate 33 is electrically connected to the engagement pin 34 through the dish portion 37, and the engagement pin 34 is electrically connected to the connection plate 26. The connection plate 26 is electrically connected to the terminal 27. Thus, the positive electrode 16 of the electrode body 2 is electrically connected to the terminal 27 through the reversal plate 33.

  FIG. 3 is a sectional perspective view showing the relief valve 10, and FIG. 4 is a sectional view showing the relief valve 10. The relief valve 10 includes a cap 40, an elastic sheet 41, a metal plate 42, and a porous sheet 43.

  The cap 40 is arranged on the upper surface of the lid 21. The cap 40 includes a top plate 44, a peripheral wall 45, and a collar 46.

  The top plate 44 is formed in a plate shape, and a communication hole 47 is formed in the center of the top plate 44. The communication hole 47 is formed, for example, in a circular shape, and the diameter of the communication hole 47 is, for example, about 1 mm to 3 mm. The communication hole (second communication hole) 47 communicates the accommodation space 48 with the outside of the accommodation case 3.

  The peripheral wall 45 is formed to extend from the outer peripheral edge of the top plate 44 toward the lid 21. The collar 46 is formed to extend from the lower end of the peripheral wall 45 along the surface of the lid 21.

  The cap 40 is fixed to the upper surface of the lid 21 by welding or the like, and the cap 40 and the lid 21 form a housing space 48 for housing the elastic sheet 41, the metal plate 42, and the porous sheet 43. That is, the cap 40 and the lid 21 form a housing portion that houses the elastic sheet 41, the metal plate 42, and the porous sheet 43.

  A communication hole (first communication hole) 49 is formed in the lid 21, and the communication space 49 communicates the accommodation space 48 with the space inside the accommodation case 3.

  The elastic sheet 41, the metal plate 42, and the porous sheet 43 are laminated in the vertical direction. In the example shown in FIGS. 3 and 4, the elastic sheet 41 is elastic in the direction from the communication hole 49 to the communication hole 47. The sheet 41, the metal plate 42, and the porous sheet 43 are sequentially stacked.

  The elastic sheet 41 is formed in an annular shape, and the elastic sheet 41 includes a main surface 51 and a main surface 52. The main surface 51 is located on the lid 21 side, and the main surface 52 is located on the opposite side to the main surface 51.

  A through hole 50 reaching from the main surface 51 to the main surface 52 is formed in the central portion of the elastic sheet 41. The elastic sheet 41 is arranged so that the through hole 50 and the communication hole 49 communicate with each other.

  The elastic sheet 41 is made of a material that has chemical resistance and is elastically deformable, such as vinylidene fluoride (FKM), ethylene propylene rubber (EPDM), and NBR nitrile rubber (NBR).

  The metal plate 42 is arranged on the main surface 52. The metal plate 42 is formed in a plate shape, and the metal plate 42 includes a main surface 53 and a main surface 54.

  The main surface 53 is in contact with the main surface 52 of the elastic sheet 41, and the main surface 54 is located on the opposite side of the main surface 53.

  A part of the main surface 53 of the metal plate 42 is exposed from the elastic sheet 41 in the through hole 50. In FIGS. 3 and 4, the exposed portion R1 is exposed from the metal plate 42.

  Internal pressure in the housing case 3 is applied to the exposed portion R1 of the main surface 53 through the through hole 50 and the communication hole 49.

  The porous sheet 43 is arranged on the main surface 54 of the metal plate 42. The porous sheet 43 has chemical resistance to the electrolytic solution 9 and is made of an elastically deformable material. For example, the porous sheet 43 is made of polyethylene (PE), polypropylene (PP), fluororesin (PTFE, PFA), or the like.

  The average pore diameter of the porous sheet 43 is, for example, at least 10 μm or less. The porosity of the porous sheet 43 is, for example, 5% or more and 30% or less. The porosity can be calculated by the following formula (1).

Porosity (%) = {(W2-W1) / W2} × 100 ... (1)
Note that “W1” is the mass of the porous sheet 43. “W2” is a sheet without pores, has the same size as the porous sheet 43, and is the mass of the sheet formed with the same composition as the porous sheet 43.

  The porous sheet 43 includes a main surface 55, a main surface 56, and a peripheral surface 57. The main surface 55 is in contact with the main surface 54 of the metal plate 42. The main surface 56 is located on the opposite side of the main surface 55, and the communication hole 47 is located above the main surface 55.

  In the relief valve 10 described above, the elastic sheet 41 urges the metal plate 42 toward the top plate 44 of the cap 40. The metal plate 42 biases the porous sheet 43 toward the top plate 44 by the biasing force applied from the elastic sheet 41.

  The main surface 56 of the porous sheet 43 is in close contact with the top plate 44 by the biasing force applied from the metal plate 42. Therefore, the opening of the communication hole 47 located on the accommodation space 48 side is closed by the porous sheet 43. The peripheral surface 57 of the porous sheet 43 is in close contact with the inner peripheral surface of the peripheral wall 45.

  At this time, the porous sheet 43 is compressed more than in the natural state and presses the metal plate 42 toward the elastic sheet 41.

  In the power storage device 1 configured as described above, the case where the internal pressure in the housing case 3 rises will be described.

  Here, the predetermined pressure (first pressure) P1 is the operating pressure at which the relief valve 10 operates, the predetermined pressure P2 is the operating pressure of the current cutoff mechanism 8, and the predetermined pressure P3 is the operating pressure of the release valve 11. To do. The predetermined pressures (second pressures) P2 and P3 are higher than the predetermined pressure P1.

  The predetermined pressure P2 is set to, for example, the internal pressure in the housing case 3 when the power storage device 1 is in the overcharged state. The predetermined pressure P3 is set to, for example, the internal pressure in the housing case 3 when the electrode body 2 becomes extremely hot due to an internal short circuit.

  In FIG. 2, the space between the reversal plate 33 and the dish portion 37 is the atmospheric pressure. When the internal pressure P in the housing case 3 reaches the predetermined pressure P2, the welded portion between the reversal plate 33 and the top plate portion 31 is broken due to the pressure difference.

  Then, the reversing plate 33 is deformed so that the central portion of the reversing plate 33 projects toward the dish portion 37. As a result, the reversal plate 33 separates from the positive electrode current collector plate 6, and the electrical connection between the reversal plate 33 and the positive electrode current collector plate 6 is cut off. As a result, the electrical connection between the positive electrode 16 of the electrode body 2 and the terminal 27 is cut off.

  In FIG. 1, when the internal pressure P in the housing case 3 reaches a predetermined pressure P3, the portion of the lid 21 where the open valve 11 is located breaks. As a result, the gas inside the housing case 3 is exhausted to the outside, and the internal pressure P of the housing case 3 can be lowered. Note that, for example, the opening valve 11 and the current cutoff mechanism 8 are formed so that the predetermined pressure P3 becomes higher than the predetermined pressure P2.

  FIG. 5 is a cross-sectional view showing the relief valve 10 when the internal pressure in the housing case 3 rises to a predetermined pressure P1.

  When the internal pressure in the housing case 3 reaches the predetermined pressure P1, the force of the predetermined pressure P1 is applied to the exposed portion R1 of the metal plate 42.

  When the pressing force of the metal plate 42 pushed up by the internal pressure of the housing case 3 becomes larger than the pressing force of the porous sheet 43 pushing the metal plate 42, the metal plate 42 floats from the elastic sheet 41.

  Here, since the porosity of the porous sheet 43 is 5% or more and 30% or less, the porous sheet 43 is suppressed from being largely deformed by the internal pressure P in the housing case 3.

  For example, when the porosity of the porous sheet 43 is larger than 30%, the porous sheet 43 is locally deformed, and the gas in the housing case 3 may leak to the outside.

  If a large amount of gas leaks from the housing case 3, it becomes difficult for the internal pressure P in the housing case 3 to become higher than the predetermined pressure P1. As a result, for example, when the power storage device 1 is overcharged, the internal pressure P in the housing case 3 is unlikely to reach the predetermined pressure P2, and the current cutoff mechanism 8 may be difficult to operate. Similarly, when an internal short circuit occurs in the electrode body 2, the internal pressure P in the housing case 3 may not easily reach the predetermined pressure P3, and the open valve 11 may be hard to operate.

  Further, when the porosity is smaller than 5%, the porous sheet 43 becomes difficult to deform even if the internal pressure in the housing case 3 reaches the predetermined pressure P1, and the space between the metal plate 42 and the elastic sheet 41 is reduced. It becomes difficult for the gap G to be formed. As a result, even if the internal pressure in the housing case 3 reaches the predetermined pressure P1, the gas in the housing case 3 may not be discharged to the outside.

  Then, when the internal pressure P becomes higher than the predetermined pressure P1, the metal plate 42 floats from the elastic sheet 41, and a gap G is formed between the metal plate 42 and the elastic sheet 41. The gas in the housing case 3 passes through the gap G and enters the housing space 48.

  Here, since the peripheral surface 57 of the porous sheet 43 and the inner peripheral surface of the peripheral wall 45 are in close contact with each other, the gas passes through the porous sheet 43 and is exhausted to the outside from the communication hole 47.

  Since the average pore diameter of the porous sheet 43 is 10 μm or less, it is possible to increase the flow resistance until the gas A passes through the porous sheet 43 and is exhausted from the communication holes 47.

  That is, when the internal pressure P reaches the predetermined pressure P1, the gas A can be exhausted to the outside of the housing case 3, and when the internal pressure P further rises, the gas A is excessively exhausted from the housing case 3 and the internal pressure P is increased. It is possible to prevent P from becoming difficult to rise.

  For example, when the average pore diameter of the porous sheet 43 is larger than 10 μm, when the gas A in the housing case 3 reaches or exceeds the predetermined pressure P1, the gas is excessively exhausted, and the internal pressure P is less likely to be higher than the predetermined pressure P1. Become.

  As described above, in power storage device 1 according to the first embodiment, when internal pressure P reaches predetermined pressure P1, relief valve 10 operates and suppresses increase in internal pressure P in housing case 3. On the other hand, in the relief valve 10, the internal pressure P can be increased to the predetermined pressure P2 at the time of overcharging, and the current cutoff mechanism 8 can be operated.

  Similarly, when an internal short circuit or the like occurs in the electrode body 2, the internal pressure P can be raised to the predetermined pressure P3 and the open valve 11 can be operated.

  In the relief valve 10 according to the first embodiment, the plate 61 is made of metal such as aluminum. Therefore, even if water or the like enters the communication hole 47 from the outside of the relief valve 10, the metal plate 42 can prevent the water from entering the housing case 3.

  Next, a power storage device 1A including a relief valve 10A according to a comparative example will be described. Power storage device 1A has the same structure as power storage device 1 except for the relief valve 10A.

  FIG. 6 is a cross-sectional view showing the relief valve 10A of the power storage device 1A. The relief valve 10A is provided on the upper surface of the lid 21 of the housing case 3.

  The relief valve 10A includes a cap 40, an O-ring 60, a plate 61, and a spring 62.

  A communication hole 47 is formed in the cap 40, and the cap 40 is provided on the upper surface of the lid 21. The cap 40 is provided so as to cover the communication hole 49, and the cap 40 and the lid 21 form an accommodation space 48. The O-ring 60, the plate 61, and the spring 62 are housed in the housing space 48.

  The O-ring 60 is fitted in the recess 63 formed on the upper surface of the lid 21. The recess 63 is formed so as to extend in an annular shape, and the O-ring 60 is formed so as to surround the periphery of the opening of the communication hole 49 located in the accommodation space 48.

  The plate 61 is made of a metal material, for example, aluminum A1050, A3003, A5052, or the like.

  The plate 61 is arranged on the upper surface of the O-ring 60, and the plate 61 cooperates with the O-ring 60 to close the opening of the communication hole 49.

  The spring 62 is arranged between the lower surface of the top plate 44 and the plate 61. The spring 62 biases the plate 61 toward the O-ring 60, and the plate 61 is in close contact with the upper surface of the O-ring 60.

  In the power storage device 1A configured as described above, when the internal pressure P in the housing case 3 rises, the plate 61 is pushed upward by the internal pressure P in the housing case 3.

  For example, when the internal pressure P becomes higher than the predetermined pressure P1, a gap G1 is formed between the O-ring 60 and the plate 61.

  Then, the gas A in the housing case 3 enters the housing space 48 through the gap G1 and is then exhausted to the outside through the communication hole 47.

  At this time, since only the spring 62 is provided in the accommodation space 48, the flow resistance of the gas A flowing in the accommodation space 48 is low, and the gas A is immediately exhausted to the outside from the communication hole 47.

  Therefore, when the plate 61 separates from the O-ring 60, the gas A in the housing case 3 is easily exhausted to the outside, and the internal pressure P is less likely to rise from the predetermined pressure P1.

  Therefore, in the relief valve 10A according to the comparative example, it is difficult for the internal pressure P to reach the predetermined pressure P2 or the predetermined pressure P3 when overcharge occurs.

  As a result, in the power storage device 1A, it is difficult for the current cutoff mechanism 8 to operate or the opening valve 11 is difficult to open.

  Note that if the internal pressure P rises slightly above the predetermined pressure P1, it may be considered that the welding portion of the reversing plate 33 and the top plate portion 31 shown in FIG. Be done. However, if such a configuration is adopted, when an impact force is applied from the outside of the power storage device 1A, the welding portion may be broken and the reversal plate 33 may be inverted and deformed.

  Similarly, as a method of operating the release valve 11 shown in FIG. 1 when the internal pressure P is slightly higher than the predetermined pressure P1, it is possible to further reduce the thickness of the portion of the release valve 11. However, even when this configuration is adopted, the opening valve 11 may be broken when an impact force is applied from the outside of the power storage device 1A.

As described above, in power storage device 1 according to the first embodiment, it is possible to suppress the various adverse effects that occur in power storage device 1A as described above.
(Embodiment 2)
A power storage device 1B according to the second embodiment will be described with reference to FIG. Power storage device 1B includes a relief valve 10B.

  The relief valve 10 </ b> B has the same configuration as the relief valve 10 except for the protrusion 70.

  The relief valve 10 includes a protrusion 70, and the protrusion 70 is formed on the inner surface of the top plate 44. The protrusion 70 is formed so as to protrude downward from the inner surface of the top plate 44, and presses the main surface 56 of the porous sheet 43.

  Therefore, the surface pressure generated between the protrusion 70 and the main surface 56 is high. As a result, even if the gas A that has entered the accommodation space 48 passes between the peripheral surface 57 and the peripheral wall 45 of the porous sheet 43, it is suppressed from passing between the protruding portion 70 and the main surface 56. Has been done.

  As a result, the gas A that has entered the accommodation space 48 passes through the porous sheet 43 and reaches the communication hole 47.

As described above, according to the relief valve 10B according to the second embodiment, most of the gas A that has entered the accommodation space 48 can pass through the porous sheet 43. This can prevent the internal pressure P from becoming difficult to rise to the predetermined pressures P2 and P3.
(Embodiment 3)
A power storage device 1C and a relief valve 10C according to the third embodiment will be described with reference to FIG. FIG. 8 is a sectional view showing a relief valve 10C according to the third embodiment.

  The relief valve 10C is formed in the same manner as the relief valve 10 except for the shape of the porous sheet.

  The relief valve 10C includes a porous sheet 43C formed in an annular shape. The porous sheet 43C is formed in an annular shape so as to surround the opening of the communication hole 47 located in the accommodation space 48.

In the third embodiment also, the porous sheet 43C is arranged between the top plate 44 and the metal plate 42, and the porous sheet 43C is compressed and deformed by the urging force from the elastic sheet 41.
(Embodiment 4)
A power storage device 1D and a relief valve 10D according to the fourth embodiment will be described with reference to FIG.

  FIG. 9 is a sectional view showing the relief valve 10D. As shown in FIG. 9, the relief valve 10D is provided in the housing case 3.

  The relief valve 10D includes a cap 40A, an elastic sheet 41D, a metal plate 42D, and a porous sheet 43D.

  The cap 40A is provided on the inner surface of the lid 21, and is provided so as to close the opening of the communication hole 49 in the housing case 3. A housing space 48D is formed by the cap 40A and the lid 21.

  The cap 40A includes a bottom plate 44D, a peripheral wall 45D, and a collar 46D, and a communication hole 47D is formed in the bottom plate 44D. The communication hole 47D communicates the accommodation space 48D with the inside of the accommodation case 3.

  The elastic sheet 41D is formed in an annular shape, and a through hole 50D is formed in the center of the elastic sheet 41D. The elastic sheet 41D is formed so as to surround the opening of the communication hole 47D in the accommodation space 48D, and the through hole 50D communicates with the communication hole 47D.

  The metal plate 42D is arranged on the upper surface of the elastic sheet 41D. The metal plate 42D is provided so as to close the through hole 50D. The metal plate 42D is formed in a plate shape, and the metal plate 42D includes main surfaces 53D and 54D.

  The main surface 53D is located on the elastic sheet 41D side, and the main surface 54D is located on the opposite side to the main surface 53D.

  Here, the exposed portion R1D which is a part of the main surface 53 is exposed from the elastic sheet 41D in the through hole 50D. Therefore, the internal pressure P in the housing case 3 is applied to the exposed portion R1D through the communication hole 47D and the through hole 50D.

  The porous sheet 43D is provided on the main surface 54D, and the porous sheet 43D is provided so as to close the opening of the communication hole 49 in the accommodation space 48D.

  Note that, also in the fourth embodiment, the elastic sheet 41D biases the metal plate 42D toward the porous sheet 43D, and the porous sheet 43D is compressed by the biasing force from the elastic sheet 41D. . As a result, the metal plate 42D is pressed against the elastic sheet 41D.

  In the relief valve 10D configured as described above, when the internal pressure P in the housing case 3 reaches the predetermined pressure P1, the metal plate 42D is pushed up, and a gap is formed between the metal plate 42D and the elastic sheet 41D.

  Then, the gas A in the housing case 3 enters the housing space 48D. The gas A that has entered the accommodation space 48D passes through the porous sheet 43D and is exhausted to the outside from the communication hole 49.

Therefore, also in the relief valve 10D according to the fourth embodiment, even if a gap is formed between the metal plate 42D and the elastic sheet 41D, the gas A is excessively exhausted to the outside of the housing case 3. Can be suppressed. Along with this, it is possible to prevent the internal pressure P from becoming difficult to rise, and it is possible to suppress the inhibition of the drive of the current cutoff mechanism 8 and the opening valve 11.
(Example)
Next, with respect to the relief valve according to the example and the relief valve according to the comparative example, the operation of each relief valve will be compared while giving specific numerical values.

The relief valve according to the comparative example is the relief valve 10A shown in FIG.
The configuration of the relief valve according to the example is the same as that of the relief valve 10 according to the first embodiment.

  Specifically, in FIGS. 4 and 5, the communication hole 47 is formed in a circular shape, and the diameter of the communication hole 47 is 1 mm in this embodiment. The elastic sheet 41 is made of EPDM (ethylene propylene rubber), and the elastic sheet 41 has an inner diameter of 2 mm, an outer diameter of 6 mm, and a thickness of 0.5 mm.

  The outer diameter of the metal plate 42 is 5 mm, and the metal plate 42 is formed of A5052. The thickness of the metal plate 42 is 0.3 mm.

  The porous sheet 43 is made of PTFE (Teflon: registered trademark). The outer diameter of the porous sheet 43 is 7 mm. The thickness of the porous sheet 43 is 1 mm. The average pore diameter of the porous sheet 43 is 0.3 μm, and the porosity is 20%.

  The cap 40 is made of the same material as the lid 21. The collar 46 of the cap 40 is welded to the upper surface of the lid 21.

  When attaching the cap 40, first, the cap 40 is pressed against the upper surface of the lid 21 in a state where the elastic sheet 41, the metal plate 42, and the porous sheet 43 are stacked in the accommodation space 48. As a result, the elastic sheet 41 and the porous sheet 43 are compressed.

  In this state, the flange 46 of the cap 40 and the lid 21 are temporarily fixed by laser welding at several points. Then, with the load applied to the cap 40 removed, the outer peripheral edge of the collar 46 is laser-welded over the entire circumference.

  When the cap 40 is fixed to the upper surface of the lid 21 in this way, the elastic sheet 41 and the porous sheet 43 are maintained in an elastically compressed state in the cap 40.

  The lid 21 to which the relief valve 10 is attached as described above is welded to the housing case 20 to form the sealed housing case 3.

  Then, gas is supplied into the housing case 3 at a flow rate of 15 cc / sec. An internal pressure sensor is arranged in the housing case 3 to sense the internal pressure in the housing case 3.

  Similarly, also in the relief valve 10A according to the comparative example, the lid 21A is welded to the housing case 20A to form the sealed housing case 3A.

  Also in the comparative example, gas is supplied into the housing case 3A at a flow rate of 15 cc / sec. An internal pressure sensor is arranged in the housing case 3A to sense the internal pressure in the housing case 3A.

  FIG. 10 shows the internal pressure situation in the housing case 3 provided with the relief valve 10 according to the embodiment, the internal pressure situation of the housing case 3A provided with the relief valve 10A according to the comparative example, and no release valve. It is a graph which shows the internal pressure situation of a storage case.

  In the graph shown in FIG. 10, the vertical axis represents the internal pressure in the housing case, and the horizontal axis represents time. Note that at time T0, the relief valves 10 and 10A are operating.

  As is clear from the graph shown in FIG. 10, in both the housing case 3 provided with the relief valve 10 according to the example and the housing case 3A provided with the relief valve 10A according to the comparative example, the relief valve is It can be seen that the internal pressure in the storage cases 3 and 3A decreases with time after the time T0 compared to the storage case not provided.

  On the other hand, in the housing case 3 provided with the relief valve 10 according to the example, the internal pressure in the housing case 3 is less likely to decrease than in the housing case 3A provided with the relief valve 10A according to the comparative example. I understand.

  The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

  1, 1A, 1B, 1C, 1D Power storage device, 2 electrode body, 3,3A, 20, 20A housing case, 4 positive electrode terminal, 5 negative electrode terminal, 6 positive electrode current collector plate, 7 negative electrode current collector plate, 8 current interruption mechanism , 9 electrolytic solution, 10, 10A, 10B, 10C, 10D relief valve, 11 open valve, 13 positive electrode sheet, 14 separator, 15 negative electrode sheet, 16 positive electrode, 17 negative electrode, 21,21A lid, 25 resin member, 26 connection plate , 27 terminals, 30 legs, 31 top plate part, 32, 47, 47D, 50, 50D through hole, 33 reversal plate, 34 engagement pin, 35 insulating member, 36 tube part, 37 dish part, 40, 40A cap , 41, 41D elastic sheet, 42, 42D metal plate, 43, 43C, 43D porous sheet, 44 top plate, 44D bottom plate, 45, 45D peripheral wall, 46, 46 D collar, 48, 48D accommodating space, 49 communicating hole, 51, 52, 53, 53D, 54, 54D, 55, 56 main surface, 57 peripheral surface, 60 ring, 61 plate, 62 spring, 63 concave portion, 70 protruding portion 2003, 2006 JP, A gas, A1050 aluminum, G, G1 clearance, P internal pressure, P1, P2, P3 predetermined pressure.

Claims (1)

An electrode body,
A housing case for housing the electrode body,
A relief valve which is provided in the housing case and exhausts the gas in the housing case to the outside when the internal pressure in the housing case becomes equal to or higher than a first pressure.
An operating mechanism that operates when the internal pressure in the housing case reaches a second pressure higher than the first pressure;
Equipped with
The relief valve is
A housing portion having a housing space formed therein,
An elastic body disposed in the accommodation space, a metal plate and a porous sheet,
A first communication hole that communicates between the accommodation space and the inside of the accommodation case and a second communication hole that communicates between the outside of the accommodation case and the accommodation space are formed in the accommodation portion,
The elastic body, the metal plate, and the porous sheet are sequentially laminated in the accommodating space in a laminating direction from the first communication hole to the second communication hole,
The metal plate includes a first main surface located on the first communication hole side and a second main surface located on the opposite side to the first main surface,
The elastic body urges the metal plate toward the porous sheet in the stacking direction,
An exposed portion exposed from the elastic body is formed on at least a part of the first main surface of the metal plate,
Internal pressure in the housing case is applied to the exposed portion of the metal plate through the first communication hole,
The porous sheet closes the second communication hole by an urging force applied from the elastic body through the metal plate,
When the internal pressure in the housing case becomes higher than the first pressure, a gap is formed between the elastic body and the metal plate,
The power storage device in which the gas in the housing case is exhausted to the outside of the housing case through the gap, the porous sheet, and the second communication hole.

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