JP2015122201A - Secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery that is able to securely fix a collector body.SOLUTION: A secondary battery comprises: a collector terminal 101 electrically connected to the reverse plate of a current cutoff mechanism, and provided with a through-hole 501; and a resin holder 150 inserted into the through-hole 501 and fixed to the collector terminal 101 by heat caulking. A thin film part 502 projecting on the inner periphery side is provided on the inner periphery of the through hole 501 of the collector terminal 101. When a projecting part 155 is inserted into the through-hole 501, the thin film part 502 is deformed and, by means of reaction force resulting from the deformation of the thin film part 502, the projecting part 155 can be fixed in the through-hole 501.

Description

  The present invention relates to a secondary battery, and more particularly to a secondary battery provided with a current interruption mechanism.

  Conventionally, a secondary battery having a current interruption mechanism is disclosed in, for example, Japanese Patent Application Laid-Open No. 2012-230905 (Patent Document 1). Further, a conductive member connection structure, a member mounting structure, and a battery are disclosed in JP2013-161518A (Patent Document 2), JP2010-164157A (Patent Document 3), and JP2012-38522A ( It is disclosed in Patent Document 4).

JP 2012-230905 A JP 2013-161518 A JP 2010-164157 A JP 2012-38522 A

  Patent Document 1 discloses a configuration in which a current collector is inserted and held in a current collecting tab holder having a tab receiving portion. With this configuration, there is a problem that the current collector cannot be reliably fixed.

  Accordingly, an object of the present invention is to provide a secondary battery that can securely fix a current collector.

  The secondary battery according to the present invention includes a current collector provided with a through-hole, which is electrically connected to the reversing plate of the current interrupting mechanism, and is fixed to the current collector by heat caulking. A thin film portion that protrudes toward the inner peripheral side on the inner peripheral side of the through hole of the current collector, and the thin film is inserted into the through hole. The part is deformed and the protruding part can be fixed in the through hole by the reaction force.

  In the secondary battery configured as described above, the thin film portion of the current collector is deformed by interfering with the protrusion, and the current is collected while maintaining the insertion clearance to fix the outer periphery of the protrusion by the reaction force. It becomes possible to firmly fix the body.

FIG. 3 is a cross-sectional view for illustrating a current collecting terminal holding structure in the secondary battery according to the first embodiment. It is a perspective view of the holding structure of the current collection terminal in the secondary battery seen from the direction shown by the arrow II in FIG. It is sectional drawing which expands and shows the part enclosed by III in FIG. It is sectional drawing which shows the 1st manufacturing process of the holding structure of the current collection terminal shown in FIG. It is sectional drawing which shows the 2nd manufacturing process of the holding structure of the current collection terminal shown in FIG. It is sectional drawing for demonstrating the holding structure of the current collection terminal in the secondary battery according to a comparative example.

  Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a cross-sectional view for explaining a current collecting terminal holding structure in the secondary battery according to the first embodiment. FIG. 2 is a perspective view of the current collector terminal holding structure in the secondary battery as viewed from the direction indicated by arrow II in FIG. Referring to FIGS. 1 and 2, secondary battery 1 employs a structure in which a positive electrode and a negative electrode are stacked and wound in a battery case 30 through a separator impregnated with an electrolytic solution.

  A positive electrode 100 and a negative electrode protrude from the battery case 30, and the positive electrode 100 and the negative electrode are connected to a wound body in the case. The battery case 30 can employ various shapes such as a square shape and a cylindrical shape. A positive electrode 100 and a negative electrode are disposed on a sealing plate 140 provided on an end surface of the battery case 30.

  The positive electrode 100 of the secondary battery 1 is provided on the sealing plate 140. A through hole 141 is formed in the sealing plate 140, and the connection terminal 130 is fitted in the through hole 141.

  A resin insulating member 150 is disposed inside the sealing plate 140 (inside the battery case 30). The connection terminal 130 is fitted in the through hole 151 of the insulating member 150.

  The connection terminal 130 has a shape in which the diameter increases in the battery case 30, and the reverse plate 120 is welded to the large diameter portion. The reversing plate 120 has a shape with a central portion protruding in the axial direction. The connection terminal 130 is caulked and connected to the conductive member 160.

  An electrolytic solution is enclosed in the battery case 30. As the type of the electrolytic solution, a non-aqueous electrolytic solution is used when a lithium ion battery is adopted as the secondary battery 1. The nonaqueous electrolytic solution may contain an additive in addition to the nonaqueous solvent and the lithium salt as the supporting electrolyte. The secondary battery 1 is not necessarily limited to the lithium secondary battery, and may be a secondary battery using an active material other than lithium.

  The current interrupt mechanism 105 includes a reversing plate 120. The pressure sensing surface 121 of the reversing plate 120 is welded to the thin portion 111 of the current collecting terminal (current collector) 101.

  Before the current interrupting mechanism 105 operates, the current flows through the current collecting terminal 101, the thin portion 111, the pressure sensing surface 121, the reversing plate 120, and the connection terminal 130. Thereby, electric power is supplied from the secondary battery 1 to the outside. During charging, current flows in the opposite direction.

  FIG. 3 is an enlarged cross-sectional view of a portion surrounded by III in FIG. Referring to FIG. 3, insulating member 150 and current collecting terminal 101 are joined by current collecting terminal holding portion 509. The insulating member 150 has a protruding portion 155 as a shaft portion, and the protruding portion 155 fits into the through hole 501. The protruding portion 155 is fixed to the current collecting terminal 101 by pressing a hot plate against the protruding portion 155 and thermally deforming in an umbrella shape (heat caulking).

  A thin film portion 502 as a thin film portion concentric with the inner wall axis is formed on the inner wall of the through hole 501 of the current collecting terminal 101.

  Although there is a gap between the protruding portion 155 and the through hole 501, the thin film portion 502 is deformed by interference with the protruding portion 155 during insertion, and the outer periphery of the protruding portion 155 is fixed by the reaction force. As a result, the fixing is made strong while ensuring the insertability, and excellent terminal holding without backlash is realized.

  Further, since the protruding portion 155 and the thin film portion 502 interfere with each other, a part of these members may be scraped and foreign matter may be generated. However, since the through-hole 501 is closed immediately after insertion, the foreign substance cell Mixing in can be prevented.

  Although the thin film portion 502 may be provided intermittently, it is preferable that the thin film portion 502 is provided in an annular shape over the entire circumference from the viewpoint of holding the current collecting terminal 101 and from the viewpoint of processing the current collecting terminal 101.

  The thin film portion 502 is formed within the depth range of the through hole 501. In order to ensure insertability, it is desirable to install the thin film portion 502 at a position as far as possible from the bottom surface of the terminal. However, it is assumed that the tip of the deformed thin film portion 502 does not reach the countersink portion 513.

  The thickness of the thin film portion 502 is set to be equal to or less than half the diameter difference between the protrusion 155 and the through hole 501 (equal to the insertion clearance).

  The inner diameter of the thin film portion 502 is set such that the amount of interference between the protrusion 155 and the thin film portion 502 is equal to or greater than the thickness of the thin film portion 502 and the deformed tip does not reach the countersink portion 513.

  It is preferable that the tip of the projecting portion 155 has a tapered shape in order to ensure insertability.

  The protrusion 155 is inserted into the through hole 501, and the thin film portion 502 is deformed so as to cover the outer periphery of the protrusion 155, and the protrusion 155 is fixed.

  In such a configuration, the thin film portion 502 is deformed along the protruding portion 155, and the protruding portion 155 can be fixed from the outer periphery by the reaction force.

  Since the projecting portion 155 can be fixed without rattling while securing the insertion clearance, it is possible to realize terminal holding excellent in securing while securing the insertability.

  Foreign matter (resin piece, metal piece) that may be generated due to interference between the thin film portion 502 and the protruding portion 155 at the time of insertion is mixed into the battery cell because the through hole is closed by heat caulking immediately after insertion. Can be prevented.

  4 and 5 are cross-sectional views showing a method of manufacturing the current collector terminal holding structure shown in FIG. With reference to FIG. 4, first, a current collecting terminal 101 in a state where an insulating member is not inserted into the through hole 501 is prepared.

  With reference to FIG. 5, the protruding portion 155 is fitted into the through hole 501 of the current collecting terminal 101. At this time, since the thin film portion 502 is deformed and a reaction force indicated by an arrow 503 is generated, the protruding portion 155 is reliably positioned. Thereafter, the hot plate 510 is brought into contact with the current collecting terminal 101. Thereby, the current collecting terminal holding part 509 shown in FIG. 3 is completed.

  FIG. 6 is a cross-sectional view for explaining a current collecting terminal holding structure in a secondary battery according to a comparative example. Referring to FIG. 6, the inner diameter W1 of the through hole 501 is provided. A gap W2 is provided between the protruding portion 155 and the through hole 501, and the thin film portion 502 is not provided. In this case, the protrusion 155 may move in the horizontal direction. On the other hand, in the structure of FIG. 3, it can suppress that the protrusion part 155 moves to a horizontal direction.

  Although the embodiment of the present invention has been described above, the embodiment shown here can be variously modified. First, as the secondary battery 1, not only a lithium secondary battery but also various secondary batteries having a current collecting terminal 101 can be used. Further, the secondary battery can be used for in-vehicle use, stationary use, portable use, and the like.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention can be used in the field of secondary batteries equipped with a current interruption mechanism.

  DESCRIPTION OF SYMBOLS 1 Secondary battery, 30 Battery case, 100 Positive electrode, 101 Current collection terminal, 105 Current interruption mechanism, 111 Thin part, 120 Inversion board, 121 Pressure sensing surface, 130 Connection terminal, 140 Sealing board, 150 Insulation member, 160 Conductive member 501 through-hole 502 thin film portion 513 countersink.

Claims (1)

A current collector provided with a through hole, electrically connected to the reversing plate of the current interrupt mechanism;
A resin holder having a protrusion inserted into the through hole and fixed to the current collector by heat caulking,
The inner peripheral side of the through hole of the current collector is provided with a thin film portion protruding to the inner peripheral side,
The secondary battery, wherein when the protruding portion is inserted into the through hole, the thin portion is deformed and the protruding portion can be fixed in the through hole by a reaction force thereof.

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