JPWO2012147150A1 - Battery pack and single battery - Google Patents

Abstract

Provided between a plurality of single cells having gas discharge valves on the surface of the container, a duct device connected to the gas discharge valves of each of the plurality of single cells to form a gas exhaust path therein, and between the duct device and the single cells A seal member that hermetically connects the gas exhaust path and the gas exhaust valve, and the seal member is in contact with the front end of the unit cell so as to surround the gas exhaust valve. It has a lip that is elastically deformed by differential pressure.

Description

  The present invention relates to a unit cell provided with a gas discharge valve, and an assembled battery including a plurality of unit cells each having a gas discharge valve.

  As a secondary battery for driving a vehicle, a secondary battery in which a charge / discharge element group in which a positive electrode plate and a negative electrode plate are arranged via a separator is housed in a metal battery container and sealed is widely known. A lithium ion secondary battery is a typical secondary battery.

  Lithium ion secondary batteries may generate heat when overcharged or short-circuited, and high-temperature gas may be generated inside the battery. Therefore, the secondary battery is provided with a gas discharge valve that cleaves at a predetermined pressure and releases the gas when gas is generated and the internal pressure rises (see Patent Document 1).

  In the assembled battery described in Patent Document 1, a duct device that guides the gas to a predetermined path is configured so that the released gas does not diffuse into the passenger compartment. The duct device includes a plurality of through holes, and each through hole is disposed so as to cover a gas discharge valve provided in each unit cell in the assembled battery. A seal portion made of an elastic body such as rubber is provided at a connection portion between the gas discharge valve and the duct device of each unit cell in order to prevent gas leakage.

Japanese Unexamined Patent Publication No. 2009-277647

  In the assembled battery described in Patent Document 1, the sealing portion is pressed against the unit cell to ensure the airtightness of the interface. Therefore, the reaction force of the seal part itself generated by press-contacting the seal part is given to the unit cell group, the duct device, and the like.

  Although the magnitude of the reaction force depends on the structure and material of the seal portion, it may be about several N per location, and the whole assembled battery further increases in proportion to the number of single cells. This load may cause the duct device and the battery group to bend, and as a result, there is a problem in that the airtight performance at each pressure contact portion varies. In addition, when the rigidity of a duct apparatus or a single battery group is increased in order to ensure airtightness, the mass and volume of the assembled battery increase, and downsizing of the assembled battery is hindered.

According to the first aspect of the present invention, the assembled battery includes a plurality of unit cells each having a gas discharge valve on the surface of the container, and a gas exhaust path is formed therein connected to each gas discharge valve of the plurality of unit cells. A duct device, and a seal member that is provided between the duct device and the unit cell and connects the gas exhaust path and the gas exhaust valve in an airtight manner, and the seal member discharges gas at the surface of the unit cell. It has a lip that contacts the valve and elastically deforms due to the pressure difference inside and outside the gas exhaust path.
According to the second aspect of the present invention, in the assembled battery of the first aspect, it is preferable that a battery injection plug is provided in a region surrounded by the tip portion of the lip.
According to the third aspect of the present invention, in the assembled battery according to the first or second aspect, it is preferable that the sealing member is formed of an insulating rubber material.
According to the fourth aspect of the present invention, in the assembled battery according to any one of the first to third aspects, the seal member has a base portion attached to the duct device, and the lip is directed from the base portion toward the tip portion. It is preferable that the wall thickness is gradually reduced.
According to a fifth aspect of the present invention, in the assembled battery according to any one of the first to fourth aspects, the duct device includes a top plate provided with a gas discharge opening corresponding to the gas discharge valve and covering the container surface. And a top cover which is laminated on the top plate and fastened so as to come into contact with each other at a predetermined surface pressure, and forms a gas exhaust path between the top plate and the seal member is mounted on the top plate Is preferred.
According to the sixth aspect of the present invention, the assembled battery according to any one of the first to fourth aspects has an integrated mechanism for assembling and integrally assembling a plurality of single cells, and the integrated mechanism is arranged in parallel. A holder disposed between the plurality of single cells, and a pair of end plates sandwiching the plurality of single cells juxtaposed, the duct device is provided with a gas discharge opening corresponding to the gas discharge valve, A top plate that covers the surface of the container and has a seal member mounted thereon; a top cover that is laminated on the top plate and fastened so as to come into contact with each other at a predetermined surface pressure; and forms a gas exhaust path between the top plate and It is preferable to have.
According to the seventh aspect of the present invention, the cell includes a gas exhaust valve provided in a battery container in which a charge / discharge element is accommodated, a gas exhaust path formed therein, and the gas exhaust valve and the gas exhaust path. A duct device that is fastened to the battery container so as to connect to the battery container, and a seal member that is provided between the duct device and the battery container and hermetically seals the gas exhaust path and the gas exhaust valve. And a lip which contacts the surface of the battery container so as to surround the gas exhaust valve and elastically deforms due to a differential pressure inside and outside the gas exhaust path.
According to the eighth aspect of the present invention, in the unit cell of the seventh aspect, it is preferable that a battery injection plug is provided in a region surrounded by the tip of the lip.
According to the ninth aspect of the present invention, in the unit cell of the seventh or eighth aspect, it is preferable that the sealing member is formed of an insulating rubber material.
According to a tenth aspect of the present invention, in the unit cell according to any one of the seventh to ninth aspects, the seal member has a base portion attached to the duct device, and the lip is directed from the base portion toward the distal end portion. It is preferable that the wall thickness is gradually reduced.

  ADVANTAGE OF THE INVENTION According to this invention, airtightness is favorable and can provide a compact assembled battery.

FIG. 1 is an external perspective view of the assembled battery according to the first embodiment of the present invention. FIG. 2 is a partial cross-sectional perspective view of the assembled battery according to the first embodiment of the present invention. FIG. 3 is an exploded perspective view of the assembled battery according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view of the assembled battery according to the first embodiment of the present invention. FIG. 5 is a perspective view of a unit cell used in the assembled battery according to the first embodiment of the present invention. FIG. 6 is a partial cross-sectional perspective view of the seal member of the battery pack according to the first embodiment of the present invention. FIG. 7A is a partial cross-sectional view showing a normal state of the assembled battery according to the first embodiment of the present invention. FIG. 7B is a partial cross-sectional view showing a gas release state of the assembled battery according to the first embodiment of the present invention. FIG. 8 is a plan view of the battery cover of the unit cell in which the region encompassed by the seal member of the assembled battery according to the first embodiment of the present invention is hatched. FIG. 9 is a cross-sectional view of the seal member according to the first embodiment of the present invention. FIG. 10A is a diagram showing an analysis model of the assembled battery according to the first embodiment of the present invention. FIG. 10B is a diagram showing an analysis result of a gas release state of the assembled battery according to the first embodiment of the present invention. FIG. 11 is a plan view of the battery cover of the unit cell in which the region included in the seal member of the assembled battery according to the second embodiment of the present invention is hatched. FIG. 12 is a plan view of the battery cover of the unit cell in which the region included in the seal member of the assembled battery according to the third embodiment of the present invention is hatched. FIG. 13 is a plan view of the battery cover of the unit cell in which the region included in the seal member of the assembled battery according to the third embodiment of the present invention is hatched. FIG. 14 is a plan view of a battery cover of a unit cell in which a region included in a seal member of the assembled battery according to the fourth embodiment of the present invention is hatched. FIG. 15 is a plan view of a battery cover of a unit cell in which a region included in a seal member of the assembled battery according to the fourth embodiment of the present invention is hatched. FIG. 16 is an external perspective view of a unit cell according to the fifth embodiment of the present invention. FIG. 17 is a partial cross-sectional view of a unit cell according to the fifth embodiment of the present invention.

  The present invention prevents gas leakage by the seal member at the connection between the gas exhaust valve provided in the battery and the duct device forming the gas exhaust path inside being deformed by the differential pressure inside and outside the gas exhaust path. It is supposed to be configured.

-First embodiment-
(Overall configuration of battery pack)
An embodiment in which the present invention is applied to an assembled battery of a square lithium ion secondary battery (hereinafter referred to as a battery) for driving a vehicle will be described. As shown in FIGS. 1 and 2, the assembled battery 50 has a plurality of single cells 30. The plurality of single cells 30 are arranged side by side and are integrally assembled by an integrated mechanism such as an end plate 45, a battery holder 44, and a shaft 52 described later. The plurality of unit cells 30 juxtaposed are sandwiched by a pair of end plates 45 from both ends in the arrangement direction (longitudinal direction of the assembled battery 50), and the upper part is covered with a top plate 46 and a top cover 47.

  As shown in FIG. 3, the unit cells 30 have a flat rectangular parallelepiped shape, and are arranged side by side so that main surfaces 1 </ b> A having a large area among side surfaces face each other. The adjacent unit cells 30 are arranged with their directions reversed so that the positions of the positive terminal 4A and the negative terminal 4B protruding from the upper surface of the unit cell 30 are reversed.

(End plate and shaft)
The end plate 45 has a rectangular flat plate shape corresponding to the main surface 1 </ b> A of the unit cell 30. At four corners of the end plate 45, through holes 45A are provided. Between the two end plates 45, four shafts 52 are arranged corresponding to the through holes 45 </ b> A at the four corners of the end plate 45.

  As shown in FIGS. 1 to 3, the portion of the shaft 52 sandwiched between the two end plates 45 is formed as an L-shaped portion having an L-shaped cross section. At both ends of the L-shaped portion, contact plates that contact the end plate 45 are provided. A round shaft inserted into the through hole 45A of the end plate 45 is erected on the contact plate, and a male screw is formed on the round shaft. The contact plate is in contact with the inner surface of the end plate 45, and defines the distance between the two end plates 45 to a predetermined length.

  The round shaft is inserted into the through hole 45 </ b> A of the end plate 45. By attaching a nut (not shown) to the round shaft on which the external thread is formed from the outside of the end plate 45, each component sandwiched between the two end plates 45 is held in a compressed state by a predetermined amount.

(Battery holder)
As shown in FIGS. 2 and 3, battery holders 44 that hold the four corners of the unit cells 30 are arranged between the plurality of unit cells 30 arranged side by side. At the four corners of the battery holder 44, shoulder portions 44B having an L-shaped cross section are formed. As shown in FIG. 3, the inner shape of the shoulder 44 </ b> B corresponds to the shape of the four corners of the unit cell 30. Each cell 30 is constrained by the shoulders 44 </ b> B provided at the four corners of the battery holder 44. Thereby, the position of each unit cell 30 in the direction orthogonal to the longitudinal direction of the assembled battery 50 is defined.

  The outer shape of the shoulder portion 44 </ b> B of each battery holder 44 corresponds to the shape of the L-shaped portion of the shaft 52. The shoulder 44 </ b> B of the battery holder 44 is restrained by the L-shaped portion of the shaft 52. Accordingly, each unit cell 30 is held by the shaft 52 via the battery holder 44.

  A plurality of grooves 44 </ b> A are formed on both surfaces of the battery holder 44. When both surfaces of the battery holder 44 are sandwiched between the single cells 30, a flow path 44C defined by each groove 44A and the main surface 1A of the battery is formed (see FIG. 2). Cooling air for adjusting the temperature of the unit cell 30 is introduced from the outside into the channel 44C.

(Top plate and top cover)
As shown in FIGS. 1 to 4, a top plate 46 that covers the surface of the unit cell 30 is disposed above the unit cell 30. A top cover 47 is stacked on the upper side of the top plate 46. The top plate 46 and the top cover 47 are constituent members of the duct device 48 that forms the gas exhaust path 8 therein, and both are made of an aluminum alloy.

  As shown in FIGS. 2 to 4, the top plate 46 is provided with an oblong gas discharge opening 46 </ b> A at a position corresponding to a gas discharge valve 23 of each unit cell 30 described later. A seal member 49 described later is fitted into the surface of each gas discharge opening 46A on the unit cell 30 side.

  As shown in FIG. 4, recesses 47 </ b> A and 46 </ b> B corresponding to each other are formed on the lower surface of the top cover 47 and the upper surface of the top plate 46. The respective recesses 47A and 46B form a gas exhaust path 8 which is a space extending in the longitudinal direction of the assembled battery 50 when the top cover 47 and the top plate 46 are combined. The top cover 47 and the top plate 46 are fastened so as to come into contact with each other with a predetermined surface pressure when a plurality of bolts 53 are provided on the upper surface of the L-shaped portion of the shaft 52 and attached to the screw portion 52A.

  As shown in FIG. 1, at the end of the assembled battery 50 in the longitudinal direction in the gas exhaust path 8, a joint portion 48 </ b> A is extended by a joint portion 47 </ b> B of the top cover 47 and a joint portion 46 </ b> C of the top plate 46. . A hose for guiding gas to the outside of the vehicle is connected to the joint portion 48A.

  As described above, the top plate 46 is provided with a plurality of gas discharge openings 46A corresponding to the gas discharge valve 23 (see FIG. 2). The gas discharge opening 46 </ b> A is an inlet for guiding gas to the gas exhaust path 8 when the gas discharge valve 23 of the unit cell 30 is cleaved. As shown in FIGS. 2, 4, and 7 </ b> A, the seal member 49 is disposed between the top plate 46 constituting the duct device 48 and the unit cell 30 so as to cover the periphery of the gas discharge valve 23 described later. Has been. As shown in FIG. 7A, since the bottom surface of the top plate 46 is in contact with each battery holder 44, the relative distance between the seal member 49 and the battery lid 3 (the upper surface of the unit cell 30) is kept constant. I'm leaning. Details of the seal member 49 will be described later.

(Single cell)
The single battery 30 constituting the assembled battery 50 will be described. As shown in FIG. 5, the unit cell 30 includes a battery container having a battery can 1 and a battery lid 3. The battery can 1 and the battery lid 3 are both made of an aluminum alloy. The battery can 1 has a rectangular box shape having an opening at one end. The battery lid 3 has a rectangular flat plate shape and is welded so as to close the opening of the battery can 1. That is, the battery lid 3 seals the battery can 1.

  As shown in FIG. 2, the battery can 1 accommodates therein a charging / discharging element group 6 having a function of charging / discharging. The charging / discharging element group 6 is configured by laminating a belt-like positive electrode plate, a negative electrode plate, and a separator that divides both electrodes, and being wound into a flat shape. The entire interior of the charge / discharge element group 6 is impregnated with an electrolyte solution (not shown).

  As shown in FIG. 5, the battery lid 3 is provided with a metal positive electrode terminal 4 </ b> A and a negative electrode terminal 4 </ b> B that are electrically connected to the positive electrode and the negative electrode of the charge / discharge element group 6. The positive electrode terminal 4 </ b> A and the negative electrode terminal 4 </ b> B are inserted into through holes provided in the vicinity of both ends of the battery lid 3 through a sealing material (not shown) made of an insulating resin material.

  Male screws are formed in portions of the positive electrode terminal 4A and the negative electrode terminal 4B that are exposed to the outside of the unit cell 30, respectively. As shown in FIG. 3, the positive electrode terminal 4 </ b> A and the negative electrode terminal 4 </ b> B of the adjacent unit cells 30 are electrically connected by a bus bar 51 made of a metal plate material. The bus bar 51 is fastened to the positive terminal 4A and the negative terminal 4B by nuts (not shown).

(Gas discharge valve and injection port)
As shown in FIG. 5, a gas discharge valve 23 and a liquid injection port 20 are formed in the central portion of the battery lid 3. The gas discharge valve 23 provided on the container surface of the unit cell 30 is formed by partially thinning the battery cover 3 with a press so that the degree of stress concentration during internal pressure action is relatively high. Thereby, when the inside of the battery can 1 reaches a predetermined pressure (about 1 MPa in the present embodiment), as shown in FIG. 7B, the gas discharge valve 23 is preferentially broken and the gas is discharged to the outside.

  The liquid injection port 20 shown in FIG. 5 is a through hole for injecting the electrolyte into the battery can 1. The liquid injection port 20 is sealed by a liquid injection plug 22 after injecting the electrolytic solution into the battery can 1. The liquid injection stopper 22 is fixed to the battery lid 3 by welding.

(Seal member)
In order to prevent the gas from leaking to the outside when the gas discharge valve 23 of the unit cell 30 is cleaved, the seal member 49 disposed at the connection portion between the gas discharge valve 23 and the duct device 48 will be described in detail. As described above, the duct device 48 includes the top plate 46 and the top cover 47 and is connected to the gas discharge valves 23 of each of the plurality of single cells 30, and when the gas discharge valve 23 is cleaved. In addition, a gas exhaust path 8 for guiding gas to the outside of the assembled battery 50 is formed (see FIG. 4). A gas discharge opening 46 </ b> A, which is a gas inlet to the duct device 48, is provided so as to include the gas discharge valve 23 of each unit cell 30. As shown in FIG. 4, the seal member 49 is provided between the gas discharge opening 46 </ b> A and the battery lid 3. The material of the seal member 49 is EPDM (ethylene / propylene / diene rubber) which is an insulating rubber material.

  As shown in FIG. 6, the seal member 49 has an oval outline, and has a base portion 49G having an L-shaped cross section as can be seen in a partially illustrated cross section. The base portion 49G is formed as a portion that is fitted into the top plate 46 that constitutes the duct device 48. A lip 49 </ b> A that contacts the unit cell 30 extends toward the inside of the seal member 49 from the lower end of the base 49 </ b> G attached to the top plate 46.

  As shown in FIGS. 4 and 7A, the gas discharge opening 46 </ b> A is provided with a fitting stepped portion of the base portion 49 </ b> G of the seal member 49. The seal member 49 is fitted to the step portion from below the gas discharge opening 46A. The lip 49A extends inward in the circumferential direction from the base 49G toward the tip 49F, and the tip 49F is in contact with the surface of the battery lid 3. As shown in FIG. 8, the region of the surface of the battery lid 3 surrounded by the tip portion 49F has an oval shape when the tip portion 49F and the cell 30 are in contact with each other. An oval region surrounded by the tip 49F of the lip 49A is defined as a seal member inclusion region 49B including the gas discharge valve 23. As shown in FIG. 8, the injection plug 22 is also disposed in the seal member inclusion region 49 </ b> B together with the gas discharge valve 23.

  As shown in FIG. 9, the lip 49 </ b> A is disposed to be inclined with respect to the surface of the battery lid 3 in a state where the tip 49 </ b> F of the lip 49 </ b> A is in contact with the battery lid 3. The lip 49A is formed such that the diameter D1 of the distal end portion 49F is smaller than the diameter D2 of the base portion 49G. The length L2 of the lip 49A is longer than the vertical distance L1 from the base 49G of the lip 49A to the battery cover 3. Furthermore, the lip 49A is formed so that the thickness gradually decreases from the base portion 49G toward the distal end portion 49F.

(Lip deformation)
Hereinafter, the deformation of the lip 49A when the gas discharge valve 23 is opened will be described with reference to FIGS. 7A and 7B. 7A is a partial cross-sectional view showing the seal member 49 in a normal state before the gas discharge valve 23 is cleaved, and FIG. 7B is a partial cross-sectional view showing the seal member 49 just after the gas discharge valve 23 is cleaved. .

  Each unit cell 30 in the assembled battery 50 may generate heat when an overcharge or short circuit occurs, and high temperature gas may be generated inside the unit cell 30. When gas is generated, the internal pressure increases rapidly. When the internal pressure rises and the internal pressure of the unit cell 30 reaches a predetermined value, the gas discharge valve 23 is opened and the gas is released into the duct device 48 as shown in FIG. 7B. Due to the gas release, the pressure in the duct device 48 increases rapidly, and the differential pressure from the outside air increases.

  The pressure in the duct device 48 acts perpendicularly to each wall surface of the duct device 48 and the seal member 49 as schematically shown by a plurality of arrows in FIG. 7B. Since the gas exhaust path 8, which is a space in the duct device 48, communicates with the plurality of unit cells 30, a seal disposed in the unit cell 30 adjacent to the unit cell 30 in which the gas discharge valve 23 is cleaved. The same pressure acts on the member 49 and the battery lid 3.

  Since the base portion 49G is pressed outward by the increase in the differential pressure inside and outside the gas exhaust path 8, the adhesion between the base portion 49G and the top plate 46 is enhanced, and gas leaks from the interface between the top plate 46 and the base portion 49G. Is prevented. Since the lip 49A is an elastic member having low rigidity, the vicinity of the tip 49F in contact with the unit cell 30 is bent and deformed so as to bulge outward.

  Due to the deformation of the lip 49A, a strong elastic force is generated on the tip portion 49F of the lip 49A that is an elastic member, in other words, a force that pushes the tip portion 49F of the lip 49A downward is generated by the elastic force of the lip 49A. The tip 49F of the lip 49A comes into contact with the unit cell 30 with a strong force. Further, the upper surface side in the vicinity of the bent front end portion 49F is pressed against the battery lid 3 by the gas, so that the lower surface in the vicinity of the front end portion 49F comes into surface contact so that the lower surface of the front end portion 49F is in close contact with the battery lid 3. As a result, the contact interface between the lip 49A and the unit cell 30 obtains a high sealing effect, and gas leakage from the interface can be prevented.

  As described above, the same pressure is also applied to the seal member 49 disposed in the adjacent unit cell 30, so that the lip 49A is deformed to ensure airtightness. Thereby, gas does not leak from the contact interface between the other unit cell 30 in the normal state and the lip 49A.

  While the gas is being released, the state shown in FIG. 7B is maintained, but after the gas is normally released from the predetermined path to the outside, the pressure difference inside and outside the gas exhaust path 8 is gradually reduced. Become. When the gas release is finished, the lip 49A returns to the previous state by elasticity.

(Verification by numerical analysis)
In order to confirm the sealing effect by the sealing member 49 incorporated in the assembled battery 50 according to the first embodiment, numerical analysis by a finite element method was performed. FIG. 10A is a diagram showing a numerical analysis model by the finite element method, and FIG. 10B is a diagram showing a numerical analysis result by the finite element method. Taking into account the symmetry of the shape, an oval quarter shape was modeled. Considering that the rigidity of the duct device 48 is sufficiently high, a boundary condition is given to the joint portion of the seal member 49 with the duct device 48 (not shown), and the modeling of the duct device 48 is omitted.

  The contact portion between the battery lid 3 and the tip 49F of the lip 49A was given a boundary condition that the tip 49F can move in a direction parallel to the contact surface with the battery lid 3. The seal member 49 was given a general EPDM Young's modulus and Poisson's ratio as physical properties.

  As a load condition, an equally distributed load perpendicular to each surface was applied to the inner wall portion of the seal member 49 including the lip 49A. As a result of the numerical analysis, as shown in FIG. 10B, it was confirmed that the intended deformation occurred in each part of the lip 49A. From this result, the effectiveness of the sealing effect was shown.

<Effects>
According to this Embodiment described above, there can exist the following effects.
(1) A seal member 49 is provided between the duct device 48 and the unit cell 30 to connect the gas exhaust path 8 and the gas exhaust valve 23 in an airtight manner. The seal member 49 is provided with a lip 49A that is elastically deformed by a differential pressure inside and outside the gas exhaust path. The lip 49A extends inward from the base portion 49G toward the tip portion 49F, and the tip portion 49F is a single piece. The surface of the battery 30 is in contact with the gas exhaust valve 23 so as to surround it. Thereby, when the gas discharge valve 23 is cleaved, a part of the lip 49A is brought into close contact with the surface of the unit cell 30 due to the differential pressure inside and outside the gas exhaust path, thereby preventing the gas from leaking to the outside. it can.

  (2) Since the lip 49A is formed of an elastically deformable material, the reaction force generated when the lip 49A is brought into contact with the surface of the unit cell 30 can be reduced. Furthermore, since the lip 49A is formed so that the thickness gradually decreases from the base portion toward the tip portion 49F, a portion close to the contact portion with the battery lid 3 can have high flexibility. The reaction force from the lip 49A can be further reduced.

  (3) According to (2), the battery lid 3 is not pressed and deformed by the lip 49A, and the duct device 48 or the single battery 30 is caused by a reaction force generated when the lip 49A is brought into contact with the surface of the single battery 30. The group will not bend. In the prior art, it was necessary to apply a strong load to the seal member 49. However, in this embodiment, since it is not necessary to apply a strong load to the seal member 49, the strength member that bears the reaction force, the top in this embodiment. The rigidity of the screw fastening portion of the plate 46 and the top cover 47 can be reduced as compared with the conventional case. Therefore, the volume and mass of the strength member can be reduced. Thereby, the assembled battery 50 can be made lightweight and compact.

  (4) According to (1) to (3), it is possible to provide a compact assembled battery 50 having good airtightness.

  (5) According to (2), even when the contact state differs for each unit cell 30 due to the assembled state of the plurality of unit cells 30 or the warp of the top plate 46, variation in reaction force is suppressed to a small level. Can do.

  (6) In the present embodiment, the tip 49F of the lip 49A may be in contact with the outer peripheral surface of the gas discharge valve 23 of the unit cell 30 (battery lid 3). Therefore, in the conventional technique in which a sealing member such as an O-ring is pressed, it is necessary to strictly manage the relative distance between the unit cell 30 and the sealing member in the vertical direction. However, according to the present embodiment, such management is performed. It becomes unnecessary. Furthermore, it is not necessary to strictly manage the relative position in the direction parallel to the contact surface of the battery lid 3. That is, even if the assembled battery 50 is configured in a state where the top plate 46 and the battery group constituting the duct device 48 are slightly warped or the positions of the single cells 30 are slightly shifted, the sealing performance is not impaired.

  (7) As described in (6), it is not necessary to strictly manage the position of the seal member. Accordingly, it is possible to set a large tolerance in advance for the warpage of the top plate 46 and the battery group and the arrangement position. Thereby, the assembled battery 50 excellent in assemblability can be provided.

  (8) The seal member inclusion region 49 </ b> B is set so as to include the gas discharge valve 23 and the liquid injection stopper 22. Thereby, even if the liquid injection plug 22 which seals the liquid injection port 20 by laser welding has impaired flatness by welding, airtightness can be ensured.

  (9) The elastically deformable lip 49A is brought into contact with the battery lid 3. As a result, even if the internal pressure of the unit cell 30 rises and the battery cover 3 swells outward, the lip 49A of the seal member 49 absorbs the deformation by elastic deformation, that is, follows the deformation of the battery cover 3. be able to. Therefore, even when the battery lid 3 is deformed so as to swell, airtightness can be ensured.

-Second embodiment-
A second embodiment in which the present invention is applied to an assembled battery of a prismatic lithium ion secondary battery for driving a vehicle will be described. In addition, the same code | symbol is attached | subjected to the location similar to 1st Embodiment, and only a different point is demonstrated.

  In the second embodiment, as shown in FIG. 11, the distance between the gas discharge valve 23 and the injection plug 22 is relatively long, and the seal member is included so as to include only the contour shape of the gas discharge valve 23. An area 49B is set.

  As shown in FIG. 11, when the gas discharge valve 23 and the injection plug 22 are sufficiently separated from each other, the seal member inclusion region 49B can be set so as to include only the gas discharge valve 23. By including a region as small as possible, the shape accuracy of the lip 49A can be increased, so that more stable sealing performance can be secured.

-Third embodiment-
A third embodiment in which the present invention is applied to an assembled battery of a prismatic lithium ion secondary battery for driving a vehicle will be described. In addition, the same code | symbol is attached | subjected to the location similar to 1st and 2nd embodiment, and only a different point is demonstrated.

  In the third embodiment, as shown in FIGS. 12 and 13, the shape of the gas discharge valve 23 is rectangular. By making the gas discharge valve 23 rectangular, it may be possible to set the cleavage pressure with higher accuracy.

  When the relative distance between the gas discharge valve 23 and the injection plug 22 is relatively short, as shown in FIG. 12, an oval seal member inclusion region 49 </ b> B so as to include the gas discharge valve 23 and the injection plug 22. Is set. When the relative distance between the gas discharge valve 23 and the injection plug 22 is relatively long, an oval seal member inclusion region 49B is set so as to include only the gas discharge valve 23 as shown in FIG. .

  Even if the shape of the gas discharge valve 23 is rectangular, the seal member inclusion region 49B is preferably oval. The seal member inclusion region 49B can be rectangular, but the bent portion of the seal member 49 is formed in a curved shape close to an arc as compared with the case where the bent portion of the seal member 49 is a right angle. A uniform sealing effect can be obtained over the entire area.

-Fourth embodiment-
A fourth embodiment in which the present invention is applied to an assembled battery of a prismatic lithium ion secondary battery for driving a vehicle will be described. In addition, the same code | symbol is attached | subjected to the location similar to the 1st-3rd embodiment, and only a different point is demonstrated.

  In the fourth embodiment, as shown in FIGS. 14 and 15, the shape of the gas discharge valve 23 is circular. By making the gas discharge valve 23 into a circular shape, the cleavage pressure may be set with higher accuracy.

  When the relative distance between the gas discharge valve 23 and the liquid filling plug 22 is relatively short, as shown in FIG. 14, an oval seal member inclusion region 49 </ b> B so as to include the gas discharge valve 23 and the liquid injection plug 22. Is set. When the relative distance between the gas discharge valve 23 and the injection plug 22 is relatively long, a circular seal member inclusion region 49B is set so as to include only the gas discharge valve 23 as shown in FIG.

-Fifth embodiment-
A fifth embodiment in which the present invention is applied to a unit cell of a prismatic lithium ion secondary battery for driving a vehicle will be described with reference to FIGS. 16 and 17. In addition, the same code | symbol is attached | subjected to the location similar to the 1st-4th embodiment, and it demonstrates centering around difference.

  In the fifth embodiment, a seal member 49 formed of an insulating rubber material is incorporated in the unit cell 70. The unit cell 70 includes a circular gas discharge valve 23, and a resin duct device 68 is connected to the gas discharge valve 23 as shown in the figure.

  In the duct device 68, a flat plate-like base portion 68B in which a circular opening is formed, a cylinder 68C erected on the base portion 68B, and a pipe portion 68D extending in a direction orthogonal to the axis of the cylinder 68C are integrally molded. Is made up of. The base 68 </ b> B is fastened to the battery lid 3 in a state where the base 68 </ b> B is in contact with the surface of the battery lid 3. The cylinder 68C and the pipe portion 68D are connected to each other to form a gas exhaust path. The pipe portion 68D has an elliptical cross-sectional shape in order to suppress the height dimension of the unit cell 70.

  As shown in FIG. 16, the pipe portion 68D has a male joint 68A as a joint portion at one end and a female joint (not shown) as a joint portion at the other end. The outer diameter of the male joint 68A is substantially the same as the inner diameter of the female joint. A hose for guiding gas to the outside of the vehicle is connected to the male joint 68A which is a joint portion, and a closing plug is connected to the female joint.

  As shown in FIG. 17, the seal member 49 that hermetically connects the gas exhaust path and the gas exhaust valve 23 is formed inside the cylinder 68 </ b> C of the duct device 68 between the duct device 68 and the battery lid 3. It is fitted in the stepped part. The lip 49A extends inward from the base 49G attached to the duct device 68 toward the tip 49F, and the tip 49F is in contact with the surface of the battery lid 3. The thickness of the lip 49A gradually decreases from the base 49G toward the tip 49F. As described above, the unit cell 70 is provided with the lip 49 </ b> A of the seal member 49 so as to surround the gas discharge valve 23. As in the first to fourth embodiments, the lip 49A can be elastically deformed by the differential pressure inside and outside the gas exhaust path formed inside the duct device 68.

  As described above, even when the duct device 68 for guiding the gas from the gas discharge valve 23 is provided in the single cell 70, the seal member 49 is provided as in the first to fourth embodiments. Airtightness can be ensured.

  When the main surface 1A is not constrained in the case of the unit cell 70, when the internal pressure of the unit cell 30 rises due to overcharging or the like, the main surface 1A having a large area is deformed so as to protrude outward. The lid 3 is deformed so that the center is recessed. Therefore, it is preferable that the length of the lip 49A is excessively increased in advance in consideration of the dent amount of the battery lid 3, and the vicinity of the tip 49F is in surface contact in the normal state. As a result, even if the center portion of the battery lid 3 is deformed so as to be recessed inside the battery can 1, the lip 49A can be maintained in contact with the surface of the battery lid 3, so that the airtightness is kept good. Can do.

  Therefore, similarly to the first to fourth embodiments, a compact unit cell 70 that has good airtightness and can be provided.

  The assembled battery can be configured as follows using the single battery 70 having the duct device 68 individually as in the fifth embodiment. The single cells 70 are juxtaposed with the main surfaces 1A facing each other, and the male joint 68A of each single cell 70 is inserted and connected to the female joint. A male joint 68A of the cell 70 arranged at one end of the assembled battery is fitted with a hose or the like for exhausting gas outside the vehicle compartment, and a female joint of the cell 70 arranged at the other end of the assembled battery. Is fitted with a stopcock.

  When the battery holder 44 is not used as in the first embodiment when the assembled battery is configured by the plurality of unit cells 70, the battery cover 3 may be depressed because the main surface 1A of the unit cell 70 is not restrained. . Even in this case, the airtightness by the seal member 49 can be ensured by setting the length of the lip 49A sufficiently long as described above.

The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.
(1) The battery can 1 and the battery lid 3 are not limited to those made of an aluminum alloy. The battery can 1 and the battery lid 3 can be formed of various metal materials such as aluminum, nickel, steel, and stainless steel.
(2) In the first to fourth embodiments, the top plate 46 and the top cover 47 are not limited to the case where they are made of an aluminum alloy. For the purpose of weight reduction, a resin having a relatively high softening temperature may be used.

  (3) The joint portion is not limited to a case where a hose for guiding gas to the outside of the vehicle is connected. You may connect the connection part for connecting another assembled battery or a single battery to a joint part.

  (4) Furthermore, the hose is not limited to a case where the hose is led outside the vehicle. The gas may be stored in the tank by connecting to a tank mounted in the vehicle. When the gas is stored in the tank without being released to the outside, after the gas discharge valve 23 is opened, as shown in FIG. 7B, the differential pressure from the outside air is maintained and the lip 49A is maintained in a deformed state. Therefore, airtightness is also maintained.

(5) In the first to fourth embodiments, the seal member 49 may be not only fitted between the top plate 46 and the battery lid 3 but also bonded and fixed to the top plate 46 with an adhesive. Thereby, gas leakage at the interface between the top plate 46 and the seal member 49 can be reliably prevented.
(6) The charging / discharging element group 6 accommodated in the battery can 1 is not limited to a case where a positive electrode plate and a negative electrode plate are wound through a separator, but a plurality of positive electrode plates. It is good also as a laminated electrode group which laminated | stacked and the negative electrode plate through the separator.

  (7) In the fifth embodiment, the gas discharge valve 23 is not limited to a circular shape. Various shapes such as an oval shape and a rectangular shape can be employed. Furthermore, as shown in FIG. 14, the liquid injection stopper 22 together with the gas discharge valve 23 may be provided in a region surrounded by the tip 49 </ b> F of the lip 49 </ b> A.

  (8) In the first to fourth embodiments, the duct device 48 is not limited to being formed by the top cover 47 and the top plate 46. You may employ | adopt the rectangular cylindrical duct apparatus which has several through-holes connected to the gas exhaust valve 23. FIG.

  (9) The material of the seal member 49 is not limited to EPDM. Various materials having insulation and elasticity can be used. Furthermore, the material of the seal member 49 is not limited to the case where it has insulation. Instead of providing the sealing member 49 with an insulating property, for example, an insulating material may be interposed between the top plate 46 and the sealing member 49, or the material of the top plate 46 may be provided with an insulating property.

  (10) Although the lithium ion secondary battery has been described as an example, the present invention can also be applied to other unit cells such as a nickel metal hydride battery.

The present invention is not limited to the embodiment described above, and can be freely changed and improved without departing from the gist of the invention.

Claims (10)

A plurality of single cells having a gas discharge valve on the container surface;
A duct device connected to a gas exhaust valve of each of the plurality of single cells and having a gas exhaust path formed therein;
A seal member provided between the duct device and the unit cell, and sealingly connecting the gas exhaust path and the gas exhaust valve;
The seal member is a battery assembly having a lip whose tip is in contact with the surface of the unit cell so as to surround the gas exhaust valve and elastically deformed by a differential pressure inside and outside the gas exhaust path. The assembled battery according to claim 1,
An assembled battery in which an injection stopper for the battery is provided in a region surrounded by the tip of the lip. The assembled battery according to claim 1 or 2,
An assembled battery in which the sealing member is formed of an insulating rubber material. The assembled battery according to any one of claims 1 to 3,
The seal member has a base portion attached to the duct device, and the lip has a gradually decreasing thickness from the base portion toward the tip portion. The assembled battery according to any one of claims 1 to 4,
The duct device is provided with a gas discharge opening corresponding to the gas discharge valve, and a top plate covering the container surface;
A top cover that is laminated on the top plate and fastened to contact each other at a predetermined surface pressure, and forms a gas exhaust path between the top plate and the top plate;
The assembled battery in which the seal member is mounted on the top plate. The assembled battery according to any one of claims 1 to 4,
An integrated mechanism for assembling the plurality of single cells side by side;
The integration mechanism includes a holder disposed between the plurality of juxtaposed cells,
A pair of end plates sandwiching the plurality of juxtaposed cells,
The duct device is provided with a gas discharge opening corresponding to the gas discharge valve, covers the container surface, and a top plate on which the seal member is mounted;
A battery pack having a top cover stacked on the top plate and fastened so as to come into contact with each other at a predetermined surface pressure and forming the gas exhaust path between the top plate and the top plate. A gas discharge valve provided in a battery container in which a charge / discharge element is accommodated;
A gas exhaust path formed therein, and a duct device fastened to the battery container so as to connect the gas exhaust valve and the gas exhaust path;
A seal member provided between the duct device and the battery container and hermetically sealing the gas exhaust path and the gas exhaust valve;
The seal member has a lip that is in contact with the tip of the sealing member so as to surround the gas discharge valve on the surface of the battery container, and has a lip that is elastically deformed by a differential pressure inside and outside the gas exhaust path. The single battery according to claim 7,
A unit cell in which an injection stopper for the battery is provided in a region surrounded by a tip portion of the lip. The single battery according to claim 7 or claim 8,
A unit cell in which the sealing member is formed of an insulating rubber material. The single battery according to any one of claims 7 to 9,
The said sealing member has a base part with which the said duct apparatus is mounted | worn, and the said lip is a single cell from which the thickness is gradually reduced toward the front-end | tip part.

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