JP5492738B2 - Secondary battery and secondary battery module - Google Patents

Description

  The present invention relates to a secondary battery such as a lithium ion secondary battery and a secondary battery module.

  2. Description of the Related Art In recent years, large-sized prismatic lithium ion secondary batteries that can charge and discharge with a large capacity and have a high volumetric energy density have attracted attention as power sources for hybrid vehicles and electric vehicles.

  The secondary battery may generate heat and generate gas due to an abnormality such as overcharge. Accordingly, various proposals have been made regarding secondary batteries provided with a gas discharge valve that is cleaved at a predetermined pressure when gas is generated and the pressure in the battery container increases. For example, in Patent Document 1, a fitting type connecting part and a receiving type connecting part are formed in a gas discharge member (duct), and a fitting type connecting part and a receiving type of a gas discharging member provided in an adjacent battery are provided. A gas discharge structure in which a connecting portion is connected to each other has been proposed.

JP 2002-216731 A

  In Patent Document 1, a battery having a gas discharge member (duct) integrally molded with a case (battery container) with a resin, and a battery row composed of a plurality of batteries and connecting the gas discharge members of adjacent batteries are provided. It is disclosed.

  However, the battery container may be made of metal in order to have sufficient strength. Further, the duct may be manufactured separately without being integrally molded with the battery container, and the duct may be connected to the battery container in a separate process.

  A gas discharge structure in which individual ducts are connected for each battery container has not been proposed at present. Therefore, there is a demand for a secondary battery having a simple gas discharge structure in which gas does not leak at the connection portion between the duct and the battery container when the battery container is deformed by an increase in internal pressure and the gas discharge valve is opened. Yes.

The secondary battery according to the invention of claim 1 is fixed to the battery container having a metal can in which the electrode group is accommodated, a metal lid provided with a gas discharge valve by sealing the can, and the lid. And a duct for collecting and guiding the gas discharged from the gas discharge valve, and a plurality of protrusions are erected around the gas discharge valve of the lid, and the duct is made of resin , and the gas discharge It has a base part which contacts the surface of the lid in the circumference of a valve, and the base part is provided with a projection attachment hole to which a plurality of projections are attached.
A secondary battery module according to a ninth aspect of the invention is such that a plurality of the secondary batteries according to the eighth aspect are juxtaposed, and the joint portion of the pipe portion is connected to the joint portion of the pipe portion of the adjacent secondary battery, The pipe parts of a plurality of secondary batteries are connected to each other.

  According to the present invention, a secondary battery having a simple gas discharge structure capable of preventing gas leakage when a battery container is deformed by an increase in internal pressure and a gas discharge valve is opened, and a plurality of the secondary batteries are juxtaposed. The secondary battery module can be provided.

1 is a perspective view showing a secondary battery according to a first embodiment of the present invention. It is a perspective view which shows the secondary battery before the duct attachment which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the inside of the secondary battery which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the winding electrode group accommodated in the battery container of the secondary battery which concerns on the 1st Embodiment of this invention. 1 is a cross-sectional plan view of a duct of a secondary battery according to a first embodiment of the present invention. It is sectional drawing which shows the connection structure of the lid | cover and duct in the secondary battery which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the connection structure of the lid | cover and duct in the secondary battery which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the connection structure of the lid | cover and duct in the secondary battery which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the connection structure of the lid | cover and duct in the secondary battery which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows the secondary battery module which concerns on the 4th Embodiment of this invention. It is a top sectional view showing a gas guide channel of a rechargeable battery module concerning a 4th embodiment of the present invention.

An embodiment in which a secondary battery according to the present invention is applied to a lithium ion battery will be described with reference to the drawings.
[First Embodiment]
-Secondary battery-
As shown in FIG. 1, the secondary battery according to the present embodiment includes a battery container 7 and a duct 30.
-Battery container-
As shown in FIG. 2, the battery container 7 includes a can 18 and a lid 10. Both the can 18 and the lid 10 are made of aluminum. The can 18 has a rectangular box shape having an opening at one end. The lid 10 has a rectangular flat plate shape and is welded so as to close the opening of the can 18. That is, the lid 10 seals the can 18.

  The lid 10 is provided with a liquid injection port 16 for injecting an electrolytic solution into the can 18, and the liquid injection port 16 is sealed with a liquid injection plug after the electrolytic solution is injected. This liquid injection stopper is fixed to the lid 10 by welding.

-Gas exhaust valve-
A circular gas discharge valve 14 is provided near the center of the lid 10. The gas discharge valve 14 is formed thinner than the lid 10. Therefore, when the pressure in the battery container 7 rises and reaches a predetermined value, the gas discharge valve 14 is opened, gas is discharged from the battery container 7, and the pressure in the battery container 7 is reduced.

  The gas discharge valve 14 is formed integrally with the lid 10 by pressing an aluminum plate. The thin plate portion that is the gas exhaust valve 14 is formed with a predetermined groove (not shown) so that a large opening is formed when the gas exhaust valve 14 is opened.

-Winding electrode group-
As shown in FIG. 3, a wound electrode group 6 having a function of charging and discharging electricity is accommodated in the battery container 7 of the secondary battery. As shown in FIG. 4, the wound electrode group 6 is configured by winding the positive electrode foil 1 and the negative electrode foil 3 in a flat shape with the separator 5 interposed therebetween.

  The positive foil 1 is aluminum having a thickness of about 30 μm, and the negative foil 3 is copper having a thickness of about 15 μm. The separator 5 is a porous polyethylene resin. A positive electrode active material 2 is applied to both surfaces of the positive electrode foil 1, and a negative electrode active material 4 is applied to both surfaces of the negative electrode foil 3.

  In the vicinity of the ends of the positive electrode foil 1 and the negative electrode foil 3 in the winding axis direction, an exposed electrode foil surface to which the positive electrode active material 2 and the negative electrode active material 4 are not applied is provided. The electrode foil exposed surfaces of the positive electrode foil 1 and the negative electrode foil 3 are a positive electrode connecting portion and a negative electrode connecting portion, respectively, and one end of each of the positive electrode current collector plate 8 and the negative electrode current collector plate 9 is connected as shown in FIG. Is done.

  The other ends of the positive electrode current collector plate 8 and the negative electrode current collector plate 9 are connected to a positive electrode terminal 11 and a negative electrode terminal 12 disposed on the lid 10, respectively. An insulating seal member 13 for electrically insulating the terminals 11 and 12 from the lid 10 is disposed between the lid 10 and the terminals 11 and 12. Similarly, an insulating seal member (not shown) for electrically insulating the current collector plates 8 and 9 from the lid 10 is disposed between the lid 10 and the current collector plates 8 and 9.

  Thus, since the positive electrode terminal 11 and the negative electrode terminal 12 are electrically connected to the positive electrode foil 1 and the negative electrode foil 3 through the positive electrode current collector plate 8 and the negative electrode current collector plate 9, respectively, the wound electrode group 6 Charging / discharging is performed between the positive electrode active material 2 and the negative electrode active material 4.

[Connection structure between lid and duct]
Next, a connection structure between the lid 10 and the duct 30 which is a feature of the present invention will be described. As shown in FIG. 2, around the gas discharge valve 14 of the lid 10, six protrusions 15 are erected in parallel with each other toward the outside of the container. The protrusion 15 is formed in a cylindrical shape by pressing a predetermined position of the flat lid 10.

  As shown in FIG. 1, the duct 30 is fixed to the lid 10 and collects and guides the gas discharged from the gas discharge valve 14. The duct 30 is made of an elastically deformable resin (polyphenylene sulfide resin or the like).

  The duct 30 is formed by integrally molding a flat base portion 29 having a circular opening, a cylinder 28 standing on the base portion 29, and a pipe portion 20 extending in a direction perpendicular to the axis of the cylinder 28. Is made up of. The cylinder 28 and the pipe portion 20 communicate with each other to form a gas passage. In addition, the cross-sectional shape of the pipe part 20 is formed in the ellipse shape in order to suppress the dimension of the height direction of a secondary battery.

  As shown in FIGS. 1 and 5, the pipe part 20 has a male joint 26 as a joint part at one end and a female joint 25 as a joint part at the other end. The outer diameter of the male joint 26 is substantially the same as the inner diameter of the female joint 25. The male joint 26 is provided with an O-ring 27.

  Therefore, when a plurality of secondary batteries are juxtaposed, the adjacent pipe parts 20 are connected to each other by connecting the male joint 26 and the female joint 25 of the adjacent secondary batteries. The connection of the duct 30 will be described later.

  As shown in FIGS. 1 and 6, the base portion 29 is disposed in a state where the bottom surface is in contact with the surface of the lid 10 so as to cover the gas discharge valve 14. That is, the surface of the lid 10 and the bottom surface of the base portion 29 are in contact with each other around the gas discharge valve 14.

  An annular groove in plan view is formed around the gas exhaust valve 14 on the surface of the lid 10 and the bottom surface of the base 29, and an annular gasket (O-ring) 31 is disposed between the grooves. Yes.

  As shown in FIG. 6, the base portion 29 is provided with six through holes 33 through which the six protrusions 15 provided on the lid 10 are inserted. The through-hole 33 has a small-diameter portion having substantially the same diameter as the outer diameter of the protrusion 15 and a large-diameter portion having a diameter larger than the outer diameter of the protrusion 15.

  As shown in FIG. 7, the duct 30 is fixed to the lid 10 by caulking the protrusion 15 with the protrusion 15 inserted through the through-hole 33. When the projection 15 is caulked, a caulking portion 34 is formed at the tip of the projection 15.

  The caulking portion 34 is pressed against a step portion formed between the large diameter portion and the small diameter portion so as to close the large diameter portion. Therefore, the caulking portion 34 is engaged with the base portion 29 so as to press the base portion 29 against the lid 10 side.

According to the present embodiment described above, the following operational effects can be obtained.
(1) Since the through-holes 33 are respectively engaged with the plurality of protrusions 15, it is possible to prevent displacement in a direction orthogonal to the protrusions 15. Since the caulking portion 34 formed at the distal end portion of the protrusion 15 is engaged with the base portion 29 so as to press the base portion 29 toward the lid 10, the shift in the peeling direction (direction parallel to the protrusion 15) is also prevented. can do.
That is, the duct 30 is firmly fixed to the lid 10, and the duct 30 is peeled off from the lid 10 when the battery container 7 is deformed by an increase in internal pressure and when gas is ejected vigorously into the duct 30. The duct 30 can be fixed at a predetermined position on the lid 10 without any problem.

  (2) Since the duct 30 can be elastically deformed, when the pressure inside the battery container 7 rises and the cover 10 of the battery container 7 is deformed, the duct 30 follows the deformation and comes into contact with the surface of the cover 10. The flat base portion 29 is also deformed. That is, when the battery is abnormal due to overcharge or the like, and the pressure inside the battery container 7 is increased due to gas generation due to temperature rise, and the lid 10 of the battery container 7 is deformed, the displacement and separation of the duct 30 are prevented. In doing so, the base 29 of the duct 30 is deformed following the deformation of the lid 10.

  (3) Due to the effects of (1) and (2), the displacement of the gasket 31 disposed between the lid 10 and the base portion 29 of the duct 30 is prevented.

  (4) Therefore, according to the present embodiment, the secondary battery capable of preventing gas leakage at the connection portion between the duct 30 and the lid 10 when the gas discharge valve 14 is cleaved by the effects (1) to (3). Can be provided.

  (5) The plurality of projections 15 provided around the gas discharge valve 14 are engaged with the plurality of through holes 33 provided in the base portion 29 of the duct 30 so that the duct 30 can be easily placed at a predetermined position on the lid 10. Can be arranged. Furthermore, the duct 30 can be easily fixed to the lid 10 by caulking the protrusion 15 after positioning the duct 30. That is, according to the present embodiment, it is possible to provide a secondary battery excellent in productivity with a simple configuration in which the connection portion between the duct 30 and the lid 10 is simple.

  (6) Since the duct 30 is made of an integrally molded resin, it can be easily molded into an arbitrary shape, and is more productive than a metal.

[Second Embodiment]
A second embodiment of the secondary battery according to the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view showing a connection structure between the lid 10 and the duct 30 according to the second embodiment of the present invention. In the second embodiment, similarly to the first embodiment, after the duct 30 is arranged on the lid 10 (see FIG. 6), the tip of the projection 15 inserted through the through-hole 33 is irradiated with a laser, The locking portion 35 is formed by melting the tip of the protrusion 15. In addition, the fiber laser was used for the laser and it irradiated for 0.1 second with the output of 2 kW.

  When the tip of the protrusion 15 is melted, the molten metal is melted down by gravity, and a weld metal formed by solidification of the molten metal is formed as a locking portion 35 so as to close the large-diameter portion. Since the formed locking portion 35 is in close contact with and engaged with the base portion 29, the duct 30 is firmly fixed to the lid 10, and the base portion 29 of the duct 30 is prevented from peeling off.

  Although aluminum has a relatively low melting point of 660 ° C., a part of the surface of the base 29 is melted at the contact portion between the resin base 29 and the molten metal by shortening the laser irradiation time. Carbonization is prevented.

  According to the second embodiment, similarly to the first embodiment, when the lid 10 of the battery container 7 is deformed, the position 29 and the separation of the duct 30 are prevented, and the base portion 29 of the duct 30 is attached to the lid 10. Since the deformation follows the deformation, the sealing property can be reliably ensured without the gasket 31 being displaced. That is, the secondary battery has a simple structure gas discharge structure, and even if the pressure in the battery container 7 rises and the gas discharge valve 12 is cleaved, the gas from the connection portion between the lid 10 and the duct 30 is removed. A secondary battery capable of preventing leakage can be provided.

[Third Embodiment]
A third embodiment of the secondary battery according to the present invention will be described with reference to FIG. FIG. 9 is a cross-sectional view showing a connection structure between the lid 10 and the duct 30 according to the third embodiment of the present invention.

  In the third embodiment, the caulking portion 34 and the locking portion 35 in the first and second embodiments are not formed. In the third embodiment, instead of the caulking portion 34 and the locking portion 35, the duct 30 is disposed on the lid 10 after the adhesive 36 is applied to the surface of the lid 10 or the surface of the base 29 on the lid 10 side. Has been.

  The surface of the base portion 29 on the lid 10 side is in contact with and adhered to the surface of the lid 10 via an adhesive 36. Since the sealing performance of the secondary battery can be secured by the adhesive 36, the gasket 31 (see FIGS. 7 and 8) is omitted in the third embodiment. Further, since the caulking portion 34 and the locking portion 35 are not formed, the large diameter portion and the small diameter portion are not formed in the through-hole 33. Since the caulking portion 34 and the locking portion 35 are not formed, a recess into which the protrusion 15 is fitted may be formed as the protrusion mounting hole instead of the through-hole 33.

  In the third embodiment, since the duct 30 is coupled to the lid 10 by the adhesive 36, the coupling force between the duct 30 and the lid 10 is weak compared to the first and second embodiments. Therefore, it is preferable to form the base 29 relatively large in order to secure a bonding area.

  As described above, even when the lid 10 and the base 29 of the duct 30 are fixed by the adhesive 36, the battery container 7 is deformed by an increase in internal pressure, and the gas discharge valve 14 is changed as in the first and second embodiments. A secondary battery having a simple gas discharge structure that can prevent gas leakage when cleaved can be provided.

[Fourth Embodiment]
An embodiment of a secondary battery module according to the present invention will be described with reference to FIG. FIG. 10 is a perspective view of the secondary battery module. In the fourth embodiment, as shown in FIG. 10, four secondary batteries are juxtaposed to constitute a secondary battery module.

  In the secondary battery module according to the present embodiment, the pipe portions 20 of the duct 30 of the secondary battery according to the second embodiment are connected to each other. A cell holder for arranging the secondary batteries at a predetermined interval is arranged between the secondary batteries (not shown).

  As described above, the male joint 26 and the female joint 25 are formed in the duct 30 (see FIGS. 1 and 5). The pipe part 20 of the duct 30 extends in the direction in which the secondary batteries are juxtaposed. When the male joint 26 of the duct 30 and the female joint 25 of the duct 30 of the adjacent secondary battery are connected, as shown in FIG. 11, the plurality of ducts 30 form one gas guide channel.

  Since the shapes of the ducts 30 are the same, the gas guide flow path formed by the ducts 30 is open at both ends, but a closure plug 40 is attached to one end and a pipe 41 is connected to the other end. Communicating with the gas guide channel 30. That is, the pipe 41 connected to the other end is also formed as a gas guide channel, and guides the gas to a predetermined place.

  Grooves are formed on the outer periphery of the male joint 26, and an O-ring 27 is attached. The male joint 26 and the female joint 25 of the duct 30 of the adjacent secondary battery are fitted, whereby a plurality of ducts 30 are provided. The gas guide flow path formed by is sealed.

  According to the fourth embodiment, even if an abnormality such as overcharging occurs in a specific secondary battery and gas is generated due to a temperature rise inside the battery container 7 and the battery container 7 is deformed, the lid 10 is deformed. Since the base portion 29 is deformed following this, gas does not leak from the connection portion between the lid 10 and the base portion 29 when the gas discharge valve 14 is cleaved with the battery container 7 inflated.

  That is, according to the fourth embodiment, when the gas discharge valve 14 is cleaved in a state where the battery container 7 of any one of the plurality of secondary batteries is expanded, the gas guide flow without leaking. It is discharged to a predetermined place (not shown) through the road. Therefore, it is possible to provide a secondary battery module having a simple gas discharge structure that can prevent gas leakage when the battery container 7 is deformed by an increase in internal pressure and the gas discharge valve 14 is opened.

  In the secondary battery module of the present embodiment, the internal pressure of a certain battery increases and the lid 10 swells. As a result, the duct 30 is also displaced in the direction perpendicular to the axial direction of the tubular pipe portion 20 and adjacent to the male joint 26. Even if a gap is formed between the female joint 25 and the battery, the male joint 26 and the female joint 25 are hermetically sealed by the O-ring 27, so that no gas leaks.

The first to fourth embodiments can also be modified as follows.
[Modification]
(1) The duct 30 is not limited to resin, and may be formed of a thin metal plate that can be elastically deformed. That is, various materials that can be elastically deformed can be employed as the material of the duct 30.
(2) The duct 30 may be formed by integral molding, or may be formed by individually molding the pipe portion 20, the cylinder 28, and the base portion 29 and connecting them.

  (3) In the above embodiment, the duct 30 is covered by, for example, caulking the protrusion 15 or melting the tip of the protrusion 15 to form the locking portion 35 or bonding the base 29 and the lid 10. The fixing to 10 has been described. As a fixing method, these may be combined, or a screw groove may be provided at the tip of the projection, and the base 29 may be pressed to the lid side with the head of the screw, and the duct 30 may be fixed to the lid 10 with a screw. Good.

  (4) Without being limited to the case where the sealing property is secured by either the gasket 31 or the adhesive 36, the gasket 31 is installed and the lid 10 and the base portion 29 are fixed by the adhesive 36 so that the sealing property is secured. Can be further improved.

(5) The gasket 31 disposed between the lid 10 and the base 29 is not limited to the O-ring, and may be sealed with a liquid gasket.
(6) The gasket 31 and the adhesive 36 can be omitted by increasing the bonding force between the duct 30 and the base portion 29 and fixing the bottom surface of the base portion 29 to the surface of the lid 10.

  (7) In the first and second embodiments described above, the through hole 33 is provided with a large diameter portion and a small diameter portion, but the present invention is not limited to this. For example, the duct 30 may be fixed to the lid 10 by forming the through-hole 33 with substantially the same diameter as the outer diameter of the protrusion 15 and engaging the caulking portion 34 or the locking portion 35 with the upper surface of the base portion 29. . As in the first and second embodiments described above, it is preferable to provide the large-diameter portion because the caulking portion 34 or the locking portion 35 can be formed in an appropriate shape and size.

(8) The protrusion 15 is not limited to a cylindrical shape. Various shapes such as a rectangular parallelepiped shape and a cylindrical shape can be adopted. The protrusion mounting hole has a shape corresponding to the shape of the protrusion 15.
(9) The number of protrusions 15 is not limited to six. Seven or more or five or less protrusions 15 may be erected on the lid 10 at a predetermined interval so as to surround the gas discharge valve 14. However, at least two or more protrusions 15 are provided on the lid 10 so that positioning can be easily performed.

  (10) The cross-sectional shape of the pipe portion 20 of the duct 30 is not limited to an elliptical shape, and various shapes such as a circular shape and a rectangular shape can be adopted.

  (11) In the fourth embodiment, the secondary battery module has been described by taking the secondary battery of the second embodiment as an example. However, the secondary battery constituting the secondary battery module relates to the second embodiment. It is not limited to only secondary batteries. A secondary battery module can be configured by juxtaposing a plurality of the secondary batteries according to the first embodiment and the third embodiment and the various types of secondary batteries described above.

  (12) The electrode group accommodated in the can 18 of the battery container 7 is not limited to the case where the positive electrode foil 1 and the negative electrode foil 3 are wound as the wound electrode group 6 wound through the separator 5. It is good also as a laminated electrode group which laminated | stacked the positive electrode foil 1 and the negative electrode foil 3 through the separator 5. FIG.

  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.

  6: wound electrode group, 7: battery container, 10: lid, 14: gas discharge valve, 15: protrusion, 18: can, 20: pipe part, 25: female joint, 26: male joint, 27: O-ring, 28: support part, 29: base part, 30: duct, 31: gasket, 33: through-hole, 34: caulking part, 35: locking part, 36: adhesive

Claims (9)

A metal can in which an electrode group is housed, and a battery container having a metal lid provided with a gas discharge valve by sealing the can;
A duct fixed to the lid and collecting and guiding the gas discharged from the gas discharge valve, and
A plurality of protrusions are erected around the gas discharge valve of the lid,
The duct is made of resin and has a base portion that contacts the surface of the lid around the gas discharge valve, and the base portion is provided with a protrusion mounting hole to which the plurality of protrusions are attached. A secondary battery characterized by. The secondary battery according to claim 1,
The secondary battery is characterized in that the duct is an elastic member . The secondary battery according to claim 1 or 2,
The protrusion mounting hole is a through-hole through which the protrusion is inserted,
A secondary battery, wherein the duct is fixed to the lid by caulking the protrusion inserted into the through hole. The secondary battery according to claim 1 or 2,
The protrusion mounting hole is a through-hole through which the protrusion is inserted,
A locking portion is formed by melting a tip portion of the protrusion inserted through the through-hole, and the duct is fixed to the lid by engaging the locking portion with the base portion. Secondary battery. The secondary battery according to any one of claims 1 to 4,
The protrusion is cylindrical,
The protrusion mounting hole is a through-hole through which the protrusion is inserted,
The secondary battery is characterized in that the through hole has a small diameter portion having substantially the same diameter as the outer diameter of the protrusion and a large diameter portion having a diameter larger than the outer diameter of the protrusion. The secondary battery according to any one of claims 1 to 5,
A secondary battery, wherein the lid and the base of the duct are fixed with an adhesive. The secondary battery according to any one of claims 1 to 6,
A secondary battery, wherein a gasket is disposed between the lid and a base of the duct. The secondary battery according to any one of claims 1 to 7,
The duct has a cylindrical pipe portion extending in a direction in which the secondary batteries are juxtaposed, and a joint portion is formed at each end of the pipe portion. A plurality of secondary batteries according to claim 8 are juxtaposed,
The secondary battery module, wherein the pipe parts of the plurality of secondary batteries are connected to each other by connecting the joint part of the pipe part to the joint part of the pipe part of the adjacent secondary battery. .

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