JP2012094569A - Power storage unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage unit with excellent reliability capable of sufficiently adjusting an internal pressure in a case, and restraining leakage of an electrolyte.SOLUTION: The power storage unit according to the present invention comprises: at least a bottomed case 1 having a plurality of housing chambers 1a blocked by partition walls 1b; a plurality of elements 2 housed in the housing chambers 1 and electrolyte; a connection member 3 passing through the partition walls 1b and electrically connecting the plural elements 2; and a lid 5 sealing the case 1. The power storage unit has a through hole formed on the partition wall 1b, and a gas permeation rubber body 4a sealing the through hole. Gas stored inside the case 1 can be efficiently vented and exhausted by the gas permeation rubber body 4a, and leakage of the electrolyte can be restrained near the through hole by the gas permeation rubber body 4a itself.

Description

  The present invention relates to a power storage unit used for backup power supply, regeneration, or power storage of various electronic devices, hybrid vehicles, and fuel cell vehicles.

  Conventionally, the kinetic energy that is unnecessarily consumed as thermal energy from the device during operation until it stops is temporarily stored as electrical energy in the electricity storage device and reused when necessary. It has been considered to reduce the energy generated and improve the efficiency.

  At that time, a power storage unit using a power storage element capable of supplying energy necessary for operation of the device with a required output has become essential. There are two types of storage element candidates: capacitors and storage batteries.

  FIG. 9 is an exploded perspective view showing an example of a conventional power storage unit.

  In FIG. 9, this conventional power storage unit has a plurality of storage chambers 100a that are partitioned by a partition 100b inside a case 100 formed of an insulating member. In the storage chamber 100a, a capacitor element 101 having a winding shape and having a positive electrode and a negative electrode at both ends of the winding shaft and an electrolytic solution (not shown) are stored. The positive electrode and the negative electrode of the element 101 and the metal terminal plate 105 are electrically connected in the housing chamber 100a, and the terminal plates 105 are connected to each other through the communication hole 100c formed in the partition 100b. By being electrically connected, the other capacitor element 101 is electrically connected. The upper surface of the case 100 is sealed with a cover 102 made of an insulating member. Further, the cover 102 is provided with a pressure regulating valve 103 that periodically discharges gas accumulated in each storage chamber 100a to the outside. It is arranged.

  With this configuration, the conventional power storage unit has a power storage unit configuration as compared with a configuration in which each capacitor element 101 is formed using an individual case and a lid and then an independent capacitor is formed and then a connection unit is used to form the power storage unit. Since the number of parts required for the process can be reduced, the productivity can be improved and the energy density can be improved by downsizing.

  In addition to this conventional power storage unit, a communication hole 100c that ventilates each storage chamber 100a in the partition 100b and a balance circuit 104 that suppresses variation in characteristics of the plurality of capacitor elements 101 in the case 100 are provided.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

JP 2006-294721 A

  Certainly, the above configuration can improve productivity by reducing the number of parts. However, in the case of the power storage unit using the partition 100b, how efficiently gas generated by electrolytic solution decomposition is released in each storage chamber as compared to a power storage unit in which each power storage device is configured independently. It was also important to prevent the electrolyte from entering from other storage chambers.

  This is because the power storage unit using the partition 100b does not reduce the number of parts, but the partition 100b not only separates the case 100 but also functions as a conventional independent capacitor case.

  With respect to the problem of the power storage unit provided with the partition 100b, an object of the present invention is to solve such a problem and to provide a power storage unit having excellent reliability such as airtightness and gas permeability.

In order to solve the above problems, a power storage unit according to the present invention includes a bottomed outer case having a plurality of storage chambers separated by partition walls, a plurality of power storage elements and electrolytes respectively stored in the storage chambers, and partition walls A connecting member for electrically connecting the plurality of power storage elements through
It has at least a lid for sealing the outer case, and has a through hole formed in the partition wall and a gas permeable rubber body for sealing the through hole.

  With this configuration, in the power storage unit of the present invention, the gas-permeable rubber body that seals the through-hole allows the gas generated in the nearby storage chamber to pass therethrough, and the electrolyte solution passes through the through-hole to another storage chamber or an outer case. Since sealing is performed so as to prevent leakage to the outside, ventilation can be achieved between the storage chambers while ensuring airtightness, and the reliability of the power storage unit can be improved.

The disassembled perspective view which showed the electrical storage unit in Example 1 of this invention (A) The exploded perspective view which showed the element and connection member which are used for the electrical storage unit in Example 1 of this invention, (b) The perspective view which assembled the element and connection member which are used for the electrical storage unit The upper surface schematic which abbreviate | omitted the cover body and showed the connection method of the elements used for the electrical storage unit in Example 1 of this invention (A) The cross-sectional schematic which extracted and showed the arrangement | positioning location of the gas permeable rubber body of the electrical storage unit in Example 1 of this invention, (b) The location of the gas permeable rubber body from which the shape of the electrical storage unit differs was shown. Sectional schematic diagram showing excerpts, (c) Sectional schematic diagram excerpting and showing the locations of gas permeable rubber bodies having different shapes of the electricity storage unit Front sectional drawing which extracted and showed a part of electrical storage unit in Example 2 of this invention Sectional drawing which showed a part of case used for the electrical storage unit in Example 3 of this invention (A) The front view which showed the connection member used for the electrical storage unit in Example 3 of this invention, (b) The top view which showed the connection member, (c) The side view which showed the connection member (A) Partial sectional view showing a state in which pressure is applied to the case used in the power storage unit in Example 3 of the present invention. (B) Pressure is applied to the case used in the power storage unit in Example 1 of the present invention. Partial sectional view showing the state An exploded perspective view showing a conventional power storage unit

Example 1
Hereinafter, the power storage unit of the present embodiment and the inventions described in claims 1 to 4, 7, and 8 will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view showing a power storage unit of the present embodiment.

  In FIG. 1, the power storage unit of this embodiment has a plurality of partition walls 1 b provided in a square case 1 and a plurality of storage chambers 1 a partitioned by the partition walls 1 b. Each of the storage chambers 1a stores a charge / discharge element 2 and an electrolyte (not shown), and these elements 2 are electrically connected to the element 2 of the adjacent storage chamber 1a. The metal connection member 3 is electrically connected. The partition wall 1b that separates the storage chambers 1a is formed with a through hole (not shown) that allows the adjacent storage chambers 1a to communicate with each other. The gas permeable rubber body 4a is formed so as to block the through hole. Is inserted in a biased state (details will be described later). A lid 5 seals above the case 1. An exhaust hole 5a is formed in a part of the lid 5 so that the opening end thereof faces the storage chamber 1a. The exhaust hole 5a is filled with a gas so as to close the exhaust hole 5a. A transparent rubber body 4b is provided. Inside the exhaust hole 5a, there is a locking portion 5b having a narrow inner diameter such as a step shape so that the gas permeable rubber body 4b can be locked. Further, for example, a porous rubber fixture 6 is fitted into the exhaust hole 5a from the upper surface side in order to fix the gas permeable rubber body 4b of the exhaust hole 5a. The connection member 3 connected to the element 2 housed in the outermost housing chamber 1 a in the case 1 penetrates the side wall of the case 1 and is electrically joined to the external terminal 7.

  FIG. 2A is an exploded perspective view individually showing the element 2 and the connection member 3 used in the electricity storage unit of this embodiment, and FIG. 2B is the element 2 and the connection member 3 used in the electricity storage unit. It is the perspective view which joined and showed.

  FIG. 3 is a schematic top view showing a method for connecting elements used in the power storage unit in this embodiment, with the lid omitted.

  In FIG. 2A, the element 2 used in the present embodiment is not clearly shown, but a positive electrode and a negative electrode are respectively formed at a pair of opposed end portions. For example, the element 2 includes a positive electrode formed with an electrode layer on both sides of a sheet-like current collector so that the current collector is exposed at one end (current collector exposed portion) so that the electrode is configured as described above. In this configuration, the negative electrode is wound so that the current collector exposed portion protrudes in the opposite direction to face each other, and a separator is interposed between the positive electrode and the negative electrode facing each other. A plurality of elements 2 having the above-described configuration are arranged in the case 1 so that the winding axes are in parallel. The element 2 used in this embodiment is not limited to a wound shape, and may have a configuration in which a positive electrode and a negative electrode having a current collector exposed portion protruding in the opposite direction are stacked.

  With this configuration, when wound, the above-described current collector exposed portions of the positive electrode and the negative electrode are respectively formed into bundles at both ends in the winding axis direction to form element end portions 2a densely packed. In FIG. 2B, the element end 2a, which is the substantially end face, and the element joint 3a of the connection member 3 are fused and joined by laser welding or the like to achieve electrical connection.

  And the external connection part 3b which is one end part of the connection member 3 is provided with the protrusion part 3c, and the partition 1b interposed between the external connection part 3b of the connection member 3 provided in the other element 2, and two elements Each of the protrusions 3c is inserted into a relay portion (not shown) which is a notch formed in and is joined using resistance welding or the like.

  As described above, the power storage unit in the present embodiment has a configuration in which a cover 5 that seals the case 1 and a plurality of elements 2 in one case 1 are accommodated in a storage chamber 1a that is partitioned by a partition wall 1b. There is a through hole in the partition wall 1b of the power storage unit, and a gas permeable rubber body 4a is disposed so as to close the through hole.

  With this configuration, the power storage unit of the present embodiment efficiently exhausts gas or moves gas through the gas-permeable rubber body 4a between the storage chambers 1a while suppressing movement of the electrolyte solution for each storage chamber 1a. It can be carried out. Thereby, it can suppress that electrolyte solution permeates into the other storage chamber 1a from a certain storage chamber 1a. Thereby, the degree of the electrolyte impregnation in each element 2 becomes uneven due to the increase / decrease in the electrolyte, and the charge / discharge balance can be prevented from being lost.

  For example, a configuration using a conventionally known gas-liquid separation membrane or the like as a ventilation means between the storage chambers 1a can be considered as this effect. Compared with this, the gas for the electrolyte already stored in the storage chamber 1a is considered. Excellent maintenance performance of transmission function. In other words, the gas-liquid separation membrane is a member that generally permeates gas and prevents liquid permeation. However, when this membrane is impregnated with liquid, the gas permeability in the membrane deteriorates and the liquid impregnation is performed. As the gas travels, the impregnated liquid may permeate simultaneously with the permeation of gas.

  On the other hand, by using the gas permeable rubber bodies 4a and 4b, the gas permeable rubber body 4 is hardly impregnated even if an electrolytic solution adheres to it.

  Naturally, the effect of the present invention has been described using the gas permeable rubber body 4a, but the same can be said for the gas permeable rubber body 4b.

  Further, since the gas permeable rubber body 4a used in the present embodiment is a rubber material, it has a certain workability and can be processed into various shapes. Therefore, as described in Example 2 below, the gas permeable rubber body 4a and the case 1, the partition 1b, and the lid 5 that support the gas permeable rubber body 4a are processed at various points in terms of arrangement locations. The power storage unit can be arranged and adapted to the location, and the design flexibility is improved.

  Examples of materials used for the gas permeable rubber bodies 4a and 4b of the present embodiment include butyl rubber, silicon rubber, and ethylene rubber. Using the gas permeable rubber bodies 4a and 4b, in the power storage unit of this embodiment, the gas permeable rubber bodies 4a are fitted into the plurality of partition walls 1b, respectively, and the gas is moved between the plurality of storage chambers 1a so Exhaust is performed from the chamber 1a through the gas permeable rubber body 4b.

  FIG. 4A is a schematic cross-sectional view showing a gas permeable rubber body arrangement portion of the power storage unit in this embodiment, and FIG. 4B is a gas permeable rubber body 4a having a different shape of the power storage unit. FIG. 4C is a schematic cross-sectional view showing extracted locations of gas permeable rubber bodies having different shapes of the electricity storage unit.

  Furthermore, in the present embodiment, the gas permeable rubber body is not limited to the configuration in which the gas permeable rubber body 4a only blocks the through-hole as shown in FIG. 4 (a), and the gas permeable rubber body as shown in FIGS. 4 (b) and 4 (c). The structure which is provided with the collar part which has a diameter larger than the diameter of a vent hole while it exposes from a vent hole in the both ends of the insertion direction of 4a. With this configuration, the gas-permeable rubber body 4a can be more firmly fixed in the vent hole, and the infiltration of the electrolytic solution can be efficiently suppressed.

  In the present embodiment, in order to join the connecting members 3 through the partition wall 1b, for example, a through hole (not shown) used for the joining is provided, and the protrusions 3c are inserted into the through holes. At this time, it is preferable to design the arrangement of the elements 2 and the dimensions of the connection member 3 so that a gap is formed between the protrusions 3c.

  Thereby, when performing resistance welding or the like, the protrusions 3c are sandwiched and joined so as to fill the gap, and the portions other than the protrusions 3c of the external connection part 3b are more positively connected to the wall surface of the partition wall 1b. Pressed. Thereby, the sealing strength of the location facing the external connection part 3b in the partition 1b is improved.

  Further, in the shape of the connection member 3, if the plate-like member is processed as shown in FIG. 2A, a configuration in which the planar portions of the element joint portion 3a and the external connection portion 3b are directed in different directions is preferable. .

  This is because, as indicated by the arrow in FIG. 3, when the external connection portion 3b is joined, a certain stress is applied to the external connection portion 3b toward the other external connection portion 3b. At that time, the stress is also applied to the element bonding portion 3a, and the stress becomes a tension with respect to the bonding interface between the element bonding portion 3a and the element end portion 2a. When this tension is large, peeling may occur at the bonding interface, and contact resistance at the bonding interface may increase. Therefore, in order to shift the direction of the tension from the winding axis direction of the element 2 and reduce the tension applied to the bonding interface, it is preferable that the element bonding portion 3a and the external connection portion 3b are directed in different directions.

  In other words, the surface including the bonding interface between the external connection portions 3b and the surface including the interface between the element bonding portion 3a and the element end 2a are preferably located in different directions.

  As an example, in this embodiment, the external connection portion 3 b is joined from the side of the element 2.

  Furthermore, a configuration in which a buffer portion is provided between the external connection portion 3b and the element joint portion 3a, the angle of the external connection portion 3b is easily changed, and the tension is further reduced may be employed.

  By connecting a plurality of elements 2 using such a connecting member 3 to form a power storage unit, even if the element 2 designed to have a long dimension particularly in the winding axis direction is used, it is tilted sideways and inside the case. Therefore, it is possible to reduce the height, and the degree of freedom of placement increases when this power storage unit is mounted on an electronic device.

  In addition, the material of the case 1 and the lid 5 is preferably an insulating material, preferably a resin. When the lid 5 and the case 1 are joined, a cutout is provided, for example, on the inner peripheral side of the case 1 side wall so that the lid 5 can be supported by the upper portion of the case 1 and joined by ultrasonic welding or the like. I do.

  In addition, in the present Example, the structure which provided the gas permeable rubber body 4a with respect to the partition 1b was mainly demonstrated. However, the gas permeable rubber body 4a is provided on the outer wall portion of the case 1 constituting a part of each storage chamber 1a, or the gas permeable rubber body is provided at a position directly above each storage chamber 1a of the lid 5. Even if it is the structure which provided 4b, the fixed gas exhaust efficiency and the effect of liquid leakage prevention can be improved.

(Example 2)
Hereinafter, the power storage unit of the present embodiment and the inventions described in claims 5 and 6 will be described with reference to the drawings. Note that the same components as those in the first embodiment are given the same numbers for explanation.

  FIG. 5 is a front sectional view showing a part of the power storage unit of the present embodiment.

  In FIG. 5, in the power storage unit in the present embodiment, a gas permeable rubber body 11 is disposed in an exhaust hole 10 formed in the lid 5 so as to close the exhaust hole 10. The gas permeable rubber body 11 used in the present embodiment has a surface area that is exposed to the outside, the outside surface 11b, a surface that faces the inside of the case 1, and the area of the inside surface 11a that is smaller than the outside surface 11b. The presentation surface 11a has a larger configuration.

  With this configuration, in the gas permeable rubber body 11, the area of the inner surface 11 a that is the gas permeable side inside the case 1 is larger than the area of the outer surface 11 b that is the surface on the moisture intrusion side. More gas can be exhausted while preventing moisture from entering.

  Here, the area of the inner surface 11a and the area of the outer surface 11b in the present embodiment refer to the area of a plane surrounded by the edges of the openings located at both ends of the exhaust hole 10, respectively.

  In addition, the gas permeable rubber body 11 is disposed so as to face the two storage chambers 1a in which the inner surface 11a is arranged in parallel. Thereby, the gas of the some storage chamber 1a can be exhausted using the one gas permeable rubber body 11. FIG.

  Then, as shown in FIG. 5, the gas permeable rubber body 11 has a configuration in which the outer peripheral surface has a multi-step cross section and the area of the inner surface 11a and the outer surface 11b is adjusted. The gas permeable rubber body 11 is prevented from moving upward at the level difference portion of the body 11, and when trying to exhaust the plurality of storage chambers 1a, the partition wall 1b comes into contact with at least one partition wall 1b. Therefore, it is possible to suppress and fix the gas permeable rubber body 11 from moving downward.

  Further, the gas permeable rubber body 11 can be formed as the gas permeable means having a complicated shape as shown in FIG. 5 because the rubber material is processed and used as the gas permeable means as in the present invention. Because it is.

  The shapes of the gas permeable rubber body 11 and the exhaust hole 10 in the present embodiment are not limited to the above-described shapes, and are a truncated cone shape or a truncated pyramid shape configured such that the upper surface having a small area is located outside the lid body 5. There may be.

(Example 3)
Hereinafter, the present embodiment and the inventions described in claims 9 and 10 will be described with reference to the drawings, but the present embodiment is not limited to the following contents.

  FIG. 6 is a cross-sectional view showing the configuration of the case 21 and the lid 22 used in the power storage unit in the present embodiment.

  The power storage unit of the present embodiment uses the same element 2 as in the first and second embodiments, but the shapes of the case 21 and the lid 22 are different, and the shapes of the case 21 and the lid 22 of the present embodiment are two of these members. Each has a substantially semi-cylindrical shape so that a cylindrical exterior body can be formed by stacking.

  FIG. 7A is a front view showing the connecting member 23 of this embodiment, FIG. 7B is a plan view of the connecting member, and FIG. 7C is a side view of the connecting member 23. is there.

  Accordingly, the connecting member 23 connected to the element 2 also has a substantially disc-shaped element joining portion 23a in accordance with the cylindrical storage chamber 21a, and extends from the outer peripheral end of the element joining portion 23a. It has an external connection part 23b.

  As shown in FIGS. 7A to 7C, in the external connection portion 23b of this embodiment, one end of the element joint portion 23a is folded inward, and one end of the folded portion is folded outward. Consists of states. When the one end is bent outward, a crease (not shown) provided in a substantially linear shape is formed in the external connection portion 23b in a substantially vertical direction with respect to the joint interface between the element joint portion 23a and the element 2. It is preferable to bend the

  In this case, the outer wall 23b has a complicated outer wall shape because the portion to be joined to the other external connection portion 23b (not shown) can be joined in a state where the horizontal surfaces overlap each other. The through-hole or notch (not shown) formed in the side wall of 21 can be made small.

  FIG. 8A is a partial cross-sectional view showing a state in which pressure is applied to the inner wall of the case 21 of the present embodiment, and FIG. 8B shows a state in which pressure is applied to the inner wall of the case 1 in the first embodiment. It is the fragmentary sectional view shown.

  Then, when the case 21 and the lid body 22 of this embodiment are joined to form a substantially cylindrical body, as shown in FIG. 8B, when gas is generated in the housing chamber 1a, The stress of the gas applied to the bottom surface becomes a bending stress, which means that the bottom surface swells. As a result, the case 1 may be misaligned and the joint portion with the lid 5 may be peeled off. Further, in order to provide resistance to this bending stress, there is a method of increasing the thickness of the side wall and the bottom surface of the case 1. In this method, the material cost is increased as much as the thickness is increased. As a unit, there is a risk of increasing the size and weight.

  On the other hand, as shown in FIG. 8A, the inner bottom surface or the inner side surface of the case 21 and the lid 22 and the outer surfaces thereof are curved. In other words, the storage chamber 21a forms a columnar cavity, and the case 21 has a wavy wall portion and is formed by connecting cylindrical cases. With the above configuration, when gas is generated in the storage chamber 21 a, the stress of the gas applied to the inner peripheral surface becomes the tensile stress of the wall surface in the case 21. Since the stress of the gas is applied radially to the inner peripheral surface, the tensile stress generated in each stress is canceled out. Therefore, in the thinner wall thickness, the swelling due to the increase in internal pressure at the time of gas generation It is possible to obtain excellent resistance to the above. For this reason, as an electrical storage unit, weight reduction can be achieved, maintaining reliability.

  Incidentally, the connection member 23 described in the present embodiment can also be used in the first and second embodiments.

  In addition, as the element 2 used for the electrical storage unit of Examples 1 and 2, examples of the current collector include aluminum, copper, iron, nickel, and alloys thereof. Moreover, the structure which gave the etching process etc. to these electrical power collectors may be sufficient. And it is preferable that the connection member 3 joined to the element end surface 2a which is a bundle of current collectors is also made of the same material.

  The electrode layer is preferably a carbon material such as activated carbon. Further, it may be configured to further contain a binder such as celluloses or a conductive aid such as acetylene black.

  The separator is made of a porous and insulating material. Cellulose paper, polypropylene, polyethylene terephthalate (PET), polyimide, etc. are used as the porous and insulating material.

In the electrolytic solution, it is preferable to use at least one organic solvent such as carbonates such as propylene carbonate, ethylene carbonate, and dimethyl carbonate and lactones as the solvent, and tetraethylammonium tetrafluoroborate (TEABF ₄ ), Triethylmethylammonium tetrafluoroborate (TEMABF ₄ ), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF ₄ ), 1-ethyl-2,3-dimethylimidazolium tetrafluoroborate (EDMIBF ₄ ), 1, 2 , 3-trimethyl imidazolium tetrafluoroborate (TMIBF ₄₎ and 1,3-dimethyl-imidazolium tetrafluoroborate (DMIBF ₄₎ or anions to the BF ₄ ^- Besides PF ₆ ^- I The preferred anion of containing a fluorine atom.

  Alternatively, the element 2 may be used in which lithium ions are used as cations and a carbon material contained in the electrode layer of the negative electrode is occluded with a certain amount of lithium ions, so that the potential difference between the negative electrode and the positive electrode is greatly widened. In that case, examples of the carbon material include graphite, soft carbon, low-temperature fired carbon, and hard carbon.

  Although the material which comprises the said element 2 is mentioned as the electrical storage unit which used the capacitor for the element 2, the electrical storage unit of this invention is not limited only to this, It reacts with the ion in electrolyte solutions, such as a lithium secondary battery. The present invention can also be applied to a power storage unit in which a storage battery including an electrode layer and a current collector that supports the electrode layer is used for the element 2.

  As described above, in the power storage unit of the present invention, the through hole is formed in the partition wall that partitions the inside of the case and forms the accommodation chamber, and the rubber member having gas permeability is disposed so as to close the through hole. Thereby, ventilation | gas_flowing and exhaust_gas | exhaustion inside a case can be performed efficiently, and it can suppress that electrolyte solution penetrate | invades into another storage chamber from the through-hole, and can improve reliability as an electrical storage unit.

  The power storage unit of the present invention is excellent in reliability particularly in exhausting gas generated inside the case, so that the power storage device for in-vehicle use and other electronic devices that are required to be charged / discharged under severe environmental conditions It is expected to be used as

DESCRIPTION OF SYMBOLS 1, 21 Case 1a Storage chamber 1b Partition 2 Element 2a Element end part 3, 23 Connection member 3a, 23a Element junction part 3b, 23b External connection part 3c Protrusion part 4a, 4b, 11 Gas-permeable rubber body 5, 22 Lid 5a DESCRIPTION OF SYMBOLS 10 Exhaust hole 5b Locking part 6 Rubber fixture 7 External terminal 11a Inner surface 11b Outer surface

Claims (10)

A bottomed outer case having a plurality of storage chambers separated by a partition;
A storage element and an electrolytic solution accommodated together in each of the plurality of storage chambers,
A connection member for electrically connecting the plurality of power storage elements respectively;
And at least a lid for sealing the outer case,
A power storage unit, wherein the partition wall is provided with a through hole, and a gas permeable rubber body for sealing the through hole is provided. The power storage unit according to claim 1, wherein the gas permeable rubber body includes at least one of butyl rubber, silicon rubber, and ethylene rubber. The through hole and the gas permeable rubber body are respectively disposed in the respective partition walls, and an exhaust hole is formed in the lid body. The gas permeable rubber body is disposed in the exhaust hole of the lid body. The power storage unit according to claim 1. The power storage unit according to claim 1, wherein the gas permeable rubber body includes an exposed portion that is at least partially exposed from the through hole, and the exposed portion has a bowl shape. An exhaust hole is formed in the lid, and of the opening ends at both ends of the exhaust hole, the area of the inner opening end is larger than the area of the outer opening end, and along the inner wall of the exhaust hole. The power storage unit according to claim 1, wherein the gas permeable rubber body is disposed. 6. The electricity storage according to claim 5, wherein the exhaust hole includes a recess formed in an inner surface of the lid, and a hole formed in the bottom of the recess and communicated with the outside of the lid. unit. The pair of connection members are electrically connected to other connection members through the partition, and element junctions that are electrically connected to positive and negative electrodes formed at a pair of opposing ends of the power storage element, respectively. Each having at least an external connection,
The power storage unit according to claim 1, wherein a surface including an interface between the element joint portion and the power storage element and a surface including an interface between the external connection portion and another connection member are in different directions. The connection member connected to at least one of the electricity storage elements is composed of a plate material,
The power storage unit according to claim 7, wherein the external connection portion is configured by one end of the element joint portion and is formed by bending the one end inward. The power storage unit according to claim 1, wherein wavy curved surfaces are formed on an inner wall surface and an outer wall surface of the outer case and the lid. The power storage unit according to claim 8, wherein one end of an external connection portion formed by bending one end of the element joint portion is bent outward.