JP2017079153A - Square secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a square secondary battery capable of suppressing the occurrence of a resin burr at a lid.SOLUTION: A square secondary battery 100 of the present invention includes: a lid 6 for sealing an opening 1a of a battery can 1 that incorporates a wound electrode group 3 therein; and collector plates 24, 44 connected to the wound electrode group 3, penetrating through through- holes 60A, 60B provided to the lid 6, and fixed to the lid 6 by a mold resin of an insulating member 5. The square secondary battery is characterized in that the lid 6 is provided with projecting portions 61a, 61b, and 61c that are in contact with the circumference of the mold resin of the insulating member 5.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a prismatic secondary battery in which an electrode terminal is supported on a lid of a battery can via an insulating member.

  As a conventional example, a rectangular plate-shaped metal lid member in which a power generation body is housed in a bottomed square box-shaped metal battery case having a rectangular opening at one end, and the opening is fixed to the battery case. In the prismatic secondary battery hermetically sealed by the battery, one end (lower end) of the metal terminal plate (current collector plate) is conductively connected to the power generator in the battery case, and the other end (upper end) is connected to the lid member. Through the formed through-hole in a non-contact state with the lid member and projecting outward (upward) of the lid member, the through-hole is made of a synthetic resin molded on the lid member by insert molding including the other end side of the terminal plate What was sealed by the insulation mold part is disclosed by patent document 1. FIG.

JP 2012-243405 A

  In the prismatic secondary battery of the conventional example, the cover member is not provided with a convex portion for blocking the flow of the mold resin. Therefore, when a clearance gap with the mold die occurs, the battery member of the cover member or the electrolyte solution There is a possibility that a resin burr may be generated in the welded portion with the liquid injection hole and cause welding failure of the welded portion. Furthermore, when a gas discharge valve is provided as a safety mechanism on the lid member, the occurrence of the resin burr on the gas discharge valve may affect the normal operation of the valve.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a prismatic secondary battery capable of suppressing the occurrence of resin burrs on the gas discharge valve, which affects welding and safety. Is to provide.

  In order to solve the above problems, a prismatic secondary battery according to one embodiment of the present invention includes a lid that seals an opening of a battery can containing an electrode group, and a through hole that is connected to the electrode group and provided in the lid. In addition, in the secondary battery having a current collector plate fixed to the lid with an insert-molded mold resin, a convex portion that contacts the mold resin is provided on the lid.

  According to the present invention, the convex portions around the mold resin exert an effect of blocking the flow of the mold resin, prevent resin leakage to the welded portion between the battery can and the lid and the gas discharge valve, It is possible to provide a prismatic secondary battery capable of suppressing the generation of resin burrs that affect safety. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

The external appearance perspective view of a square secondary battery. The disassembled perspective view of a square secondary battery. The exploded perspective view of a wound electrode group. FIG. 3 is a perspective view of a lid according to the first embodiment. FIG. 3 is a perspective view of the lid assembly according to the first embodiment. FIG. 6 is an enlarged sectional view taken along line XX in FIG. 5. FIG. 6 is an enlarged sectional view taken along line YY in FIG. 5. The perspective view of the lid | cover of Example 2. FIG. The perspective view of the lid | cover of Example 3. FIG. The perspective view of the lid | cover of Example 4. FIG. The perspective view of the lid | cover of Example 5. FIG.

Embodiments of the present invention will be described below with reference to the drawings.
[Example 1]
FIG. 1 is an external perspective view of a prismatic secondary battery.
The prismatic secondary battery 100 includes a battery can 1 and a lid 6. The battery can 1 and the lid 6 are made of a metal material such as an aluminum alloy, for example, and are formed by deep drawing and pressing.

  A wound electrode group 3 (see FIG. 2) is built in the battery can 1, and the opening 1 a of the battery can 1 is sealed with a lid 6. The lid 6 has a substantially rectangular flat plate shape, and is welded so as to close the opening 1 a of the battery can 1 to seal the battery can 1. The lid 6 is provided with a positive electrode output portion 14 fixed to the lid 6 by an insulating member 5 by insert molding and a negative electrode output portion 12. The wound electrode group 3 is charged via the positive electrode output unit 14 and the negative electrode output unit 12, and power is supplied to the external load. The lid 6 is integrally provided with a gas discharge valve 10, and when the pressure in the battery container rises, the gas discharge valve 10 opens to discharge gas from the inside, and the pressure in the battery container is reduced. Thereby, the safety of the prismatic secondary battery 100 is ensured.

FIG. 2 is an exploded perspective view of the prismatic secondary battery.
The battery can 1 of the rectangular secondary battery 100 includes a rectangular bottom surface 1d, a wide surface 1b rising from a pair of long sides of the bottom surface 1d, a narrow surface 1c rising from a pair of short sides of the bottom surface 1d, and the wide surface 1b. And an opening 1a opened upward at the upper end of the narrow surface 1c. A wound electrode group 3 is accommodated in the battery can 1 via an insulating protective film 2.

  The wound electrode group 3 is formed by winding a strip-like electrode into a flat shape, and is formed continuously between a pair of curved portions facing each other and having a semicircular cross section, and the pair of curved portions. And a flat portion. The wound electrode group 3 is inserted into the battery can 1 from one curved portion side so that the winding axis direction is along the lateral width direction of the battery can 1 and faces the bottom surface 1d, and the other curved portion side is an opening. It is arranged on the 1a side.

  The positive electrode foil exposed portion 34 c of the wound electrode group 3 is electrically connected to the positive electrode output portion 14 provided on the lid 6 via the positive electrode current collector plate 44. Further, the negative electrode foil exposed portion 32 c of the wound electrode group 3 is electrically connected to the negative electrode output portion 12 provided on the lid 6 via the negative electrode current collector plate 24. As a result, power is supplied from the wound electrode group 3 to the external load via the positive current collector plate 44 and the negative current collector plate 24, and the wound electrode group 3 is provided via the positive current collector plate 44 and the negative current collector plate 24. Externally generated power is supplied to and charged.

  The positive electrode current collector plate 44 and the negative electrode current collector plate 24 are integrally fixed to the lid 6 and supported by the insulating member 5 while being inserted through the positive electrode side through hole 60A and the negative electrode side through hole 60B of the lid 6 by insert molding. The Moreover, after injecting electrolyte solution into the battery can 1 from the liquid injection hole 9, the liquid injection stopper 11 is joined to the lid 6 by laser welding to seal the liquid injection hole 9, and the rectangular secondary battery 100 is sealed. .

  Here, examples of the material for forming the positive electrode current collector plate 44 include an aluminum alloy, and examples of the material for forming the negative electrode current collector plate 24 include a copper alloy. Examples of the material for forming the insulating member 5 include resin materials having insulation properties such as polybutylene terephthalate, polyphenylene sulfide, and perfluoroalkoxy fluororesin.

Further, the lid 6 is provided with a liquid injection hole 9 for injecting the electrolytic solution into the battery can 1. The liquid injection hole 9 is injected after the electrolytic solution is injected into the battery can 1. Sealed by a stopper 11. Here, as the electrolytic solution injected into the battery can 1, for example, a non-aqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is dissolved in a carbonate-based organic solvent such as ethylene carbonate. Can be applied.

  The positive electrode output unit 14 and the negative electrode output unit 12 have a weld joint that is welded to a bus bar or the like. The welded joint has a flat surface disposed above the insulating member 5 and in parallel with the outer surface 6a of the lid 6, and a bus bar or the like is brought into contact with the flat surface to be welded. Yes.

  The positive electrode current collector plate 44 and the negative electrode current collector plate 24 extend toward the bottom surface along the wide surface of the battery can 1, and face the positive electrode foil exposed portion 34 c and the negative electrode foil exposed portion 32 c of the wound electrode group 3. The positive electrode connecting portion 42 and the negative electrode connecting portion 22 are connected in a state where they are overlapped.

  The insulating protective film 2 is wound around the wound electrode group 3 with the direction along the flat plane of the wound electrode group 3 and the direction orthogonal to the wound axis direction of the wound electrode group 3 as the central axis direction. . The insulating protective film 2 is made of, for example, a single sheet made of synthetic resin such as PP (polypropylene) or a plurality of film members, and is parallel to the flat surface of the wound electrode group 3 and orthogonal to the winding axis direction. It has a length that can be wound around the direction as the winding center.

FIG. 3 is an exploded perspective view showing a state in which a part of the wound electrode group is developed.
The wound electrode group 3 is configured by winding a negative electrode 32 and a positive electrode 34 in a flat shape with separators 33 and 35 interposed therebetween. In the wound electrode group 3, the outermost electrode is the negative electrode 32, and separators 33 and 35 are wound further outside. The separators 33 and 35 have a role of insulating between the positive electrode 34 and the negative electrode 32.

  The portion of the negative electrode 32 where the negative electrode mixture layer 32b is applied is larger in the width direction than the portion of the positive electrode 34 where the positive electrode mixture layer 34b is applied. The negative electrode mixture layer 32b is always sandwiched between the coated portions. The positive foil exposed portion 34c and the negative foil exposed portion 32c are bundled at a plane portion and connected by welding or the like. The separators 33 and 35 are wider than the portion where the negative electrode mixture layer 32b is applied in the width direction, but are wound at positions where the metal foil surface at the end is exposed at the positive electrode foil exposed portion 34c and the negative electrode foil exposed portion 32c. Therefore, it does not hinder bundle welding.

  The positive electrode 34 has a positive electrode active material mixture on both sides of a positive electrode foil that is a positive electrode current collector, and a positive electrode foil exposed portion where no positive electrode active material mixture is applied to one end in the width direction of the positive electrode foil 34c is provided. The negative electrode 32 has a negative electrode active material mixture on both sides of a negative electrode foil that is a negative electrode current collector, and a negative electrode foil exposed portion where no negative electrode active material mixture is applied to the other end in the width direction of the negative electrode foil 32c is provided. The positive electrode foil exposed portion 34c and the negative electrode foil exposed portion 32c are regions where the metal surface of the electrode foil is exposed, and are wound so as to be disposed on one side and the other side in the winding axis direction.

  Regarding the negative electrode 32, 10 parts by weight of polyvinylidene fluoride (hereinafter referred to as PVDF) is added as a binder to 100 parts by weight of amorphous carbon powder as a negative electrode active material, and N as a dispersion solvent. -A negative electrode mixture in which methylpyrrolidone (hereinafter referred to as NMP) was added and kneaded was prepared. This negative electrode mixture was applied to both surfaces of a 10 μm thick copper foil (negative electrode foil) leaving a welded portion (negative electrode uncoated portion). Then, the negative electrode 32 with a negative electrode active material application part thickness of 70 micrometers which does not contain copper foil was obtained through drying, a press, and a cutting process.

In this embodiment, the case where amorphous carbon is used as the negative electrode active material is exemplified, but the present invention is not limited to this. Natural graphite capable of inserting and removing lithium ions and various artificial graphite materials , Carbonaceous materials such as coke, compounds such as Si and Sn (for example, SiO, TiSi ₂ etc.), or composite materials thereof may be used. It is not limited.

Regarding the positive electrode 34, 10 parts by weight of flaky graphite as a conductive material and 10 parts by weight of PVDF as a binder are added to 100 parts by weight of lithium manganate (chemical formula LiMn ₂ O ₄ ) as a positive electrode active material. A positive electrode mixture was prepared by adding and kneading NMP as a dispersion solvent. This positive electrode mixture was applied to both surfaces of an aluminum foil (positive electrode foil) having a thickness of 20 μm leaving a welded portion (positive electrode uncoated portion). Thereafter, a positive electrode 34 having a thickness of 90 μm in the thickness of the positive electrode active material coating portion not including an aluminum foil was obtained through drying, pressing, and cutting processes.

  Further, in the present embodiment, the case where lithium manganate is used as the positive electrode active material is exemplified, but other lithium manganate having a spinel crystal structure or a lithium manganese composite oxide or layered in which a part is substituted or doped with a metal element A lithium cobalt oxide or lithium titanate having a crystal structure, or a lithium-metal composite oxide obtained by substituting or doping a part thereof with a metal element may be used.

  Moreover, in this embodiment, although the case where PVDF was used as a binder of the coating part in a positive electrode and a negative electrode was illustrated, polytetrafluoroethylene (PTFE), polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, styrene Use polymers such as butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various latexes, acrylonitrile, vinyl fluoride, vinylidene fluoride, propylene fluoride, chloroprene fluoride, acrylic resins, and mixtures thereof. Can do.

  Moreover, as a shaft core, what was comprised by winding the resin sheet whose bending rigidity is higher than any of positive electrode foil, negative electrode foil, and separators 33 and 35 can be used, for example.

  4A and 4B are perspective views of the lid in the first embodiment. FIG. 4A shows an upper surface that is an outer surface of the lid, and FIG. 4B shows a lower surface that is an inner surface of the lid. ing. 5 is a perspective view of the lid assembly according to the first embodiment, FIG. 6 is an enlarged sectional view taken along line XX of FIG. 5, and FIG. 7 is an enlarged sectional view taken along line YY of FIG.

  As shown in FIG. 4B, the inner surface 6 b of the lid 6 is provided with convex portions 61 a, 61 b, 61 c that come into contact with the periphery of the insulating member 5. The convex portion 61c is continuously formed in a circumferential shape along the outer edge portion of the lid 6 (first convex portion). The convex portion 61 c is inserted into the inside of the battery can 1 from the opening 1 a of the battery can 1 and is disposed so as to face the inner surface of the wide surface 1 b and the narrow surface 1 c of the battery can 1. A welded portion that is welded to the battery can 1 is formed on the inner surface 6b of the lid 6 and outside the convex portion 61c.

  The convex portion 61a is provided between the positive electrode side through hole 60A through which the positive electrode current collector plate 44 penetrates and the gas exhaust valve 10 disposed adjacent to the through hole 60A, and the convex portion 61b is provided as the negative electrode current collector plate. 24 is provided between the through hole 60B on the negative electrode side through which 24 penetrates and the liquid injection hole 9 or the gas discharge valve 10 disposed adjacent to the through hole 60B (second convex portion). The convex portion 61a and the convex portion 61b are provided from the convex portion 61c along one long side of the lid 6 to the convex portion 61c along the other long side, and the through holes 60A and 60B A closed curve is formed in cooperation with the convex portion 61c surrounding the periphery. The convex portions 61a, 61b, 61c can be formed by, for example, pressing. In the press working, the concave groove 61d is formed first, and the convex portions 61a, 61b, 61c are formed by the excess meat. The concave groove 61d is formed outside the convex portions 61a, 61b, 61c.

  The convex portions 61a, 61b, 61c form a closed curve surrounding the peripheries of the through holes 60A, 60B. For example, as shown in FIGS. 6 and 7, the periphery of the member lower portion 52 of the insulating member 5 is brought into contact therewith. Yes. The insulating member 5 fixes the positive electrode output portion 14 and the negative electrode output portion 12 to the lid 6 in a state where the periphery of the member lower portion 52 is in contact with the convex portions 61a, 61b, 61c. The insulating member 5 has a member upper portion 51 formed on the outer surface 6 a side of the lid 6 and a member lower portion 52 formed on the inner surface 6 b side of the lid 6.

  The insulating member 5 is filled with mold resin from a mold die (not shown) disposed on the outer surface 6a side of the lid 6 at the time of insert molding, and the member lower portion 52 of the insulating member 5 passes through the through holes 60A and 60B. The lid 6 is formed by flowing mold resin from the outer surface 6a side to the inner surface 6b side.

  The convex portions 61a, 61b, and 61c exhibit an effect of blocking the mold resin of the insulating member 5 that flows from the through holes 60A and 60B toward the inner surface 6b of the lid 6 during insert molding. And the gas discharge provided for the welding part with the battery can 1 which is an outer side part from the convex part 61c of the lid | cover 6, the part to which the liquid injection stopper 11 of the liquid injection hole 9 is welded, or a safety mechanism The mold resin can be prevented from flowing onto the valve 10. Therefore, the resin leak to the welding part of the battery can 1 and the lid | cover 6 and the gas exhaust valve 10 can be prevented, and generation | occurrence | production of the resin burr | flash which affects weldability and safety | security can be suppressed.

  The convex portions 61 a, 61 b and 61 c are in contact with the periphery of the insulating member 5, and the height from the inner surface 6 b of the lid 6 is lower than that of the insulating member 5. At the time of insert molding, the mold 200 is disposed so as to be in contact with the tips of the convex portions 61a, 61b, 61c, and the mold resin is filled into the cavity on the inner surface 6b side of the lid 6 through the through holes 60A, 60B. In the mold 200, the height of the insulating member 5 is raised so that the insulating member 5 can be sufficiently insulated and sealed and the resin pressure during filling is received by the mold. Molded higher than the tip.

  6 and 7, only the configuration on the negative electrode side is shown, but the present embodiment is not limited to the negative electrode side, as long as at least one of the positive electrode side and the negative electrode side has such a configuration. In this embodiment, the positive electrode side has the same configuration as the negative electrode side.

[Example 2]
8A and 8B are perspective views of the lid of the second embodiment. FIG. 8A shows the top surface of the lid, and FIG. 8B shows the bottom surface of the lid.
As shown in FIG. 8B, convex portions 62 a and 62 b are provided on the inner surface 6 b of the lid 6. The convex portions 62a and 62b are provided so as to surround the peripheries of the through holes 60A and 60B, respectively, and form a closed curve. And the welding part welded to the battery can 1 is formed in the inner surface 6b of the lid | cover 6, and an outer edge part. The convex portions 62a and 62b can be formed by, for example, pressing. In the case of press working, the concave groove 62c is formed first, and the convex portions 62a and 62b are formed by the surplus meat. The concave groove 62c is formed outside the convex portions 62a and 62b.

  The convex portions 62a and 62b form a closed curve surrounding the peripheries of the through holes 60A and 60B, and a member lower portion 52 (see FIGS. 6 and 7) of the insulating member 5 is in contact therewith. The insulating member 5 is filled with mold resin from the outer surface 6a side of the lid 6 during insert molding. The member lower portion 52 of the insulating member 5 is formed by allowing mold resin to flow from the outer surface 6a side to the inner surface 6b side of the lid 6 through the through holes 60A and 60B.

  The convex portions 62a and 62b exert an effect of blocking the mold resin of the insulating member 5 that flows from the through holes 60A and 60B toward the inner surface 6b of the lid 6 during insert molding. And it is provided for the welding part with the battery can 1 which is an outer side part from the convex parts 62a and 62b of the lid | cover 6, the part to which the liquid injection stopper 11 of the liquid injection hole 9 is welded, or a safety mechanism. Mold resin can be prevented from flowing onto the gas discharge valve 10. Therefore, the resin leak to the welding part of the battery can 1 and the lid | cover 6 and the gas exhaust valve 10 can be prevented, and generation | occurrence | production of the resin burr | flash which affects weldability and safety | security can be suppressed.

  The convex portions 62 a and 62 b are in contact with the periphery of the insulating member 5 as in the first embodiment, and the height from the inner surface 6 b of the lid 6 is lower than that of the insulating member 5. At the time of insert molding, the mold die is disposed so as to be in contact with the tips of the convex portions 62a and 62b, and the mold resin is filled into the cavity on the inner surface 6b side of the lid 6 through the through holes 60A and 60B. In the mold 200, the insulating member 5 can be sufficiently high in insulation and sealing, and the height of the insulating member 5 is the tip of the protrusions 62a and 62b so as to receive the resin pressure during filling with the mold. Molded higher.

[Example 3]
FIG. 9 is a perspective view of the lid of Example 3, FIG. 9A shows the upper surface of the lid, and FIG. 9B shows the lower surface of the lid.
As shown in FIG. 9A, convex portions 63 a and 63 b are provided on the outer surface 6 a of the lid 6. The convex portions 63a and 63b are provided so as to surround the peripheries of the through holes 60A and 60B, respectively, and form a closed curve. The convex portions 63a and 63b form a closed curve surrounding the peripheries of the through holes 60A and 60B, and a member upper portion 51 (see FIGS. 6 and 7) of the insulating member 5 is brought into contact therewith.

  And as shown in FIG.9 (b), the convex part 64a is provided in the inner surface 6b of the lid | cover 6. As shown in FIG. The convex portion 64a is provided in a circumferential shape along the outer edge of the lid 6 and forms a closed curve. A member lower portion 52 (see FIGS. 6 and 7) of the insulating member 5 is partially in contact with the convex portion 64a. The convex portion 64a is inserted into the inside of the battery can 1 from the opening 1a of the battery can 1, and is disposed to face the inner surface of the wide surface 1b and the narrow surface 1c of the battery can 1. A welded portion to be welded to the battery can 1 is formed on the inner surface 6b of the lid 6 and outside the convex portion 64a.

  The convex portions 63a, 63b, and 64a can be formed by, for example, pressing. In the case of pressing, concave grooves 63c and 64c are first formed, and convex portions 63a, 63b, and 64a are formed by the surplus meat. The concave grooves 63c and 64c are formed outside the convex portions 63a, 63b and 64a.

  The insulating member 5 is filled with mold resin from the outer surface 6a side of the lid 6 during insert molding. The convex portions 63a and 63b exhibit an effect of blocking the mold resin of the insulating member 5 that flows into the outer surface 6a side of the lid 6 during insert molding, and the convex portion 64a flows into the inner surface 6b side of the lid 6. Demonstrates the effect of blocking the mold resin. Then, the outer side of the convex portions 63a, 63b, 64a of the lid 6 is the portion where the liquid injection stopper 11 of the liquid injection hole 9 is welded, or the gas discharge valve 10 provided for the safety mechanism. The mold resin can be prevented from flowing into the welded portion with the battery can 1. Therefore, it is possible to prevent resin leakage and suppress the occurrence of resin burrs that affect weldability and safety. Further, even when an insulating film or the like is applied to the outer surface 6a of the lid 6 for the purpose of insulation, it is possible to avoid poor application due to the presence of resin burrs.

  The convex portions 63 a, 63 b and 64 a abut against the periphery of the insulating member 5, and the height from the inner surface 6 b of the lid 6 is lower than that of the insulating member 5. At the time of insert molding, the mold 200 is disposed so as to be in contact with the tips of the convex portions 63a, 63b, 64a, and the mold resin is filled in the cavities on the outer surface 6a side and the inner surface 6b side of the lid 6. In the mold die, the insulating member 5 can be sufficiently secured and sealed, and the height of the insulating member 5 is such that the protrusion 63a, 63b, 64a has a height so that the resin pressure during filling is received by the mold die. Molded higher than the tip.

[Example 4]
FIG. 10 is a perspective view of the lid of Example 4, FIG. 10 (a) shows the top surface of the lid, and FIG. 10 (b) shows the bottom surface of the lid.
In the present embodiment, convex portions 63a and 63b are provided on the outer surface 6a of the lid 6, and convex portions 61a, 61b and 61c are provided on the inner surface 6b. Therefore, on both sides of the outer surface 6a and the inner surface 6b of the lid 6, the portion to which the liquid injection stopper 11 of the liquid injection hole 9 is welded, the gas discharge valve 10 provided for the safety mechanism, the battery can 1 and The mold resin can be prevented from flowing into the welded portion. Therefore, it is possible to prevent resin leakage and suppress the occurrence of resin burrs that affect weldability and safety. Further, even when an insulating film or the like is applied to the outer surface 6a of the lid 6 for the purpose of insulation, it is possible to avoid poor application due to the presence of resin burrs.

[Example 5]
FIG. 11 is a perspective view of the lid of Example 5, FIG. 11 (a) shows the top surface of the lid, and FIG. 11 (b) shows the bottom surface of the lid.
In the present embodiment, convex portions 62 a and 62 b are provided on the inner surface 6 b of the lid 6, and convex portions 63 a and 63 b are provided on the outer surface 6 a of the lid 6. The convex portions 62a and 62b exert an effect of blocking the mold resin of the insulating member 5 that flows from the through holes 60A and 60B toward the inner surface 6b of the lid 6 during insert molding. And the convex parts 63a and 63b exhibit the effect which dams up with respect to the mold resin of the insulating member 5 which flows into the outer surface 6a side of the lid | cover 6 at the time of insert molding.

  Therefore, on both sides of the outer surface 6a and the inner surface 6b of the lid 6, the portion of the liquid injection hole 9 to which the liquid injection stopper 11 is welded, the gas discharge valve 10 provided for the safety mechanism, the battery can 1 and The mold resin can be prevented from flowing into the welded portion. Therefore, it is possible to prevent resin leakage and suppress the occurrence of resin burrs that affect weldability and safety.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 Battery can 1a Opening part 1b Wide surface 1c Narrow surface 1d Bottom surface 2 Insulating protective film 3 Winding electrode group 5 Insulating member 6 Lid 8a Electrode group fixing tape 8b Insulating protective film fixing tape 9 Injection hole 10 Gas discharge valve 11 Note Liquid stopper 12 Negative electrode output part 14 Positive electrode output part 22 Negative electrode connection part 24 Negative electrode current collector plate 32 Negative electrode 32b Negative electrode mixture layer 32c Negative electrode foil exposed part 33 Separator 34 Positive electrode 34b Positive electrode mixture layer 34c Positive electrode foil exposed part 35 Separator 42 Positive electrode connection portion 44 Positive electrode current collector plate 70 Lid assembly 100 Square secondary battery 200 Mold

Claims (6)

A lid for sealing an opening of a battery can containing the electrode group; a current collector plate connected to the electrode group, penetrating through a through-hole provided in the lid, and fixed to the lid with an insert-molded mold resin; In a rectangular secondary battery having
A prismatic secondary battery, wherein the lid is provided with a convex portion that contacts the periphery of the mold resin.   The prismatic secondary battery according to claim 1, wherein the convex portion forms a closed curve.   The prismatic secondary battery according to claim 2, wherein the convex portion is lower than a height of the mold resin from the lid.   The prismatic secondary battery according to claim 3, wherein the convex portion is provided on an inner surface of the lid.   The convex portion is provided between a first convex portion that is circumferentially continuous along the outer edge of the lid, and the injection hole or gas discharge valve that is disposed adjacent to the through hole and the through hole. The prismatic secondary battery according to claim 4, further comprising a second protrusion. The prismatic secondary battery according to any one of claims 3 to 5, wherein the convex portion is provided on an outer surface of the lid.

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