JP2005190697A - Secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery withstanding strong vibration and shock, reduced in assembling cost, also reduced in inner resistance, and having a high output. <P>SOLUTION: This battery is provided with: an electrode plate group 5 in which a positive electrode plate and a negative electrode plate are opposed via a separator, and which is composed by being wound around by a winding core 3 as the axis, and in which a core material that a mixture layer of the positive electrode plate is not applied to is exposed on one end face in the width direction and the core material that a mixture layer of the negative electrode plate is not applied to is exposed on the other end face; a positive electrode current collecting plate 16 connected to the one end face of the electrode plate group 5; a negative electrode current collecting plate 6 connected to the other end face of the electrode plate group 5; a negative terminal 11 fixed to the winding core 3 together with either of negative electrode current collecting plates 6 by a connecting member 17; an exterior case 2 to house the electrode plate group 5; an upper cap body 7 and a lower cap body 4 which seal an aperture of the exterior case 2 and in which the negative terminal 11 is penetrated through the battery via insulation rings 8, 10; and an electrolytic solution which is impregnated inside the electrode plate group 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a secondary battery, and more particularly to a secondary battery that can be suitably applied to a rectangular lithium secondary battery whose cross-sectional shape is rectangular, rounded rectangle, or oval.

  In recent years, lithium secondary batteries have been widely used as power sources for electronic devices such as portable communication devices and notebook personal computers. In addition, demands for resource saving and energy saving for protection of the global environment are increasing, and development of a lithium secondary battery as a battery power source for driving a motor in an electric vehicle or a hybrid electric vehicle is being promoted.

  In order to improve the output characteristics and productivity of lithium secondary batteries, it is desirable to use parts with low electrical resistance and shorten the current path, and for this purpose, there is a method of connecting these current path parts by welding. Are known.

  However, there is a problem that the welding operation is complicated and the electrical resistance is large because the connection area is small. Therefore, a method is also known in which current collecting leads from a positive electrode plate or a negative electrode plate are directly brought into pressure contact with an electrode terminal (see, for example, Patent Document 1).

As shown in FIG. 5, the electrode plate group and the electrode terminal are connected with a pair of arm pieces 25, 25 at the base end of the electrode terminal 23 facing the winding electrode body 21 inside the battery can 22. Protruding collars 24 are provided, and the leading ends of a plurality of current collecting leads 26 extending from the winding electrode body 21 are overlapped to form a lead bundle 27. The lead bundle 27 is a pair of arm pieces. The lead bundles 27 are pressed and connected to the flange portion 24 by the pressing force of the distal end portions by inserting between the 25 and 25 and bending the distal end portions of both arm pieces 25 and 25 inward.
JP 2002-42770 A

  However, in the conventional secondary battery, the current collecting lead 26 is taken out from the positive electrode plate and the negative electrode plate, and the current collecting lead 26 is directly welded to the electrode terminal or fixed by pressure contact. When receiving vibration or shock during use, there is a problem that the current collecting lead may be cut or the welded part or the fixed part may be broken. In addition, when the current path is connected by welding, there is a problem that an expensive welding apparatus is required, and costs are required to ensure welding quality, resulting in high costs.

  In view of the above-described conventional problems, the present invention provides a secondary battery that can secure a strong connection against vibration and impact, reduce assembly cost, and reduce the internal resistance of the battery to obtain a high output. Is an issue.

  The secondary battery of the present invention is a core in which a positive electrode plate and a negative electrode plate are opposed to each other with a separator interposed therebetween and wound around a winding core, and a positive electrode plate mixture layer is not applied to one end face in the width direction. And a positive electrode current collector bonded to one end surface of the electrode plate group, wherein the core material is exposed, and the core material on which the mixture layer of the negative electrode plate is not applied to the other end surface in the width direction is exposed. A plate, a negative electrode current collector plate joined to the other end face of the electrode plate group, an electrode terminal fixed to the winding core together with one of the current collector plates by a connecting member, and the electrode plate group are accommodated An outer case, a lid for sealing the opening of the outer case and penetrating and fixing the electrode terminal through an insulating member, and an electrolytic solution impregnated inside the electrode plate group are provided.

  According to this configuration, since the electrode terminal and the current collector plate joined to the end face of the electrode plate group are fixed to the winding core by the connecting member, welding that requires equipment cost and work man-hours is unnecessary, and the assembly man-hour can be reduced. The cost can be reduced and the mass productivity is excellent, and the electrode plate group is fixed to the lid and the outer case via the core and the electrode terminal fixed to the core, so it is resistant to vibration and impact. Furthermore, since the current collector plate joined to the end face of the electrode plate group and the electrode terminal are directly connected, the current path is short, the internal resistance is small, and a high output secondary battery can be obtained.

  In addition, when the current collector plate is sandwiched between the electrode terminal and the core, and fixed with a connecting member, the current collector plate connected to the electrode plate group is sandwiched between the strong electrode terminal and the core. Since it is held and fixed, the current collector plate can be connected to the electrode terminal with high reliability against vibration and shock.

  In addition, when the protrusion is formed at the end of the core and the opening through which the protrusion is inserted is formed in the current collector plate, the core and the current collector plate are positioned by fitting the protrusion and the opening. Is reliably prevented, and the reliability of the fixed and connected state of the electrode plate group and the current collector plate is further ensured.

  In addition, if a plurality of holes are provided in the electrode terminal, current collector plate, and core to allow the connection member to pass through, the electrode terminal, current collector plate, and core can be fixed by a plurality of connection members. A fixed state with a low connection resistance can be obtained.

  Also, if the outer case has a cylindrical shape with openings at both ends and both ends are sealed with lids, the outer case can be manufactured easily and at low cost, and an outer case of any length can be manufactured. A battery having an arbitrary capacity can be easily manufactured.

  According to the secondary battery of the present invention, since the current collector plate joined to the electrode terminal and the electrode plate group is fixed to the core of the electrode plate group by the connecting member, the number of assembling steps can be reduced and the cost can be reduced. In addition to being excellent in mass productivity, the electrode plate group is fixed to the lid and outer case via its core and electrode terminals, so it is resistant to vibrations and shocks, and has a short current path and low internal resistance. An output secondary battery can be obtained.

  Hereinafter, an embodiment of a secondary battery of the present invention will be described with reference to FIGS.

  1 and 2, reference numeral 1 denotes a secondary battery made of a lithium ion battery, in which an electrode plate group 5 is electrolyzed in a rectangular case with a flat cross-sectional shape, or a rounded rectangular or oval rectangular cylindrical case 2. It is configured to be stored together with the liquid and sealed with the lower lid body 4 and the upper lid body 7. The outer case 2 is made of a pultruded product of an aluminum material having anti-electrolytic solution characteristics.

  The electrode plate group 5 is configured by stacking a positive electrode plate and a negative electrode plate with a separator interposed therebetween and winding the thin plate-like core 3 around an axis. A negative electrode core material to which the negative electrode mixture of the negative electrode plate is not applied is exposed on the upper end face of the electrode plate group 5, and a positive electrode core material to which the positive electrode mixture of the positive electrode plate is not applied is exposed on the lower end face. Yes. Here, the end surface on the upper lid 7 side of the electrode plate group 5 is referred to as an upper end surface, and the end surface on the lower lid 4 side is referred to as a lower end surface. The positive electrode current collector plate 16 is joined to the positive electrode core material exposed on the lower end surface of the electrode plate group 5 by welding, and the negative electrode core material exposed on the upper end surface of the electrode plate group 5 is connected to the negative electrode. The current collector plate 6 is joined by welding.

  As shown in FIG. 3, welding of the negative electrode core member exposed on the upper end face of the electrode plate group 5 and the negative electrode current collector plate 6 forms protrusions 6a at a plurality of locations on the negative electrode current collector plate 6, The negative electrode current collector plate 6 is pressed against the end face of the electrode plate group 5 so that the protrusion 6a is welded in close contact with the negative electrode core material. In addition, the positive electrode core material exposed on the lower end face of the electrode plate group 5 and the positive electrode current collector plate 16 are welded to project the protrusions 16a at a plurality of locations on the positive electrode current collector plate 16, and this positive electrode current collector. The plate 16 is pressed against the end face of the electrode plate group 5 so that the protrusion 16a is welded in close contact with the negative electrode core.

  Reference numeral 11 denotes a negative electrode terminal as an electrode terminal of one polarity, and as shown in FIG. 3, a connection plate portion 11a is formed at a base end portion thereof, and a pair of holes through which the connection member 17 penetrates the connection plate portion 11a. 11b is opened. Protrusions 3a project from both ends of the core 3, and the negative electrode current collector plate 6 and the positive electrode current collector plate 16 have openings 6b and 16b through which the projecting portions 3a are inserted, respectively. On one side surface of the projecting portion 3a, there is formed a recess 3b that overlaps the rising piece 6c formed on the negative electrode current collector plate 6 and the connection plate portion 11a of the negative electrode terminal 11, and inserts a part thereof to face each other. . In addition, a hole 3 c through which the connecting member 17 passes is formed in the protruding portion 3 a so as to correspond to the hole 11 b of the negative electrode terminal 11. The rising piece 6c of the negative electrode current collector plate 6 is also provided with a hole 6d penetrating the connection member 17 corresponding to the hole 11b and the hole 3c.

  As shown in FIG. 4, the negative electrode terminal 11 and the negative electrode current collector plate 6 are caulked and fixed together with a winding core 3 by a connecting member 17 made of a material having a low electric resistance such as copper, and are connected to each other. Further, on the outer periphery of the negative electrode terminal 11, a lower insulating ring 8 having a cylindrical portion and a flange portion at the lower end thereof is disposed, and an O-ring 9 as a sealing means is further disposed. In addition, a square ring, D ring, X ring, etc. can be used as a sealing means.

  A safety valve 13 that releases internal gas in response to a rise in internal pressure is caulked and fixed to the upper lid body 7 via a safety valve spacer 14. The upper lid 7 is formed with a cylindrical hole 7a through which the negative electrode terminal 11 passes, and the cylindrical portion of the lower insulating ring 8 disposed in the negative electrode terminal 11 and the O-ring 9 are fitted into the cylindrical hole 7a. Further, the cylindrical portion of the upper insulating ring 10 having a cylindrical portion and a flange portion at the upper end thereof is fitted and inserted into the cylindrical hole 7a, and a fixing ring 12 engaged with the flange portion is formed at the upper end portion of the negative electrode terminal 11. It is mounted and fixed in the formed fixing groove 11c. Further, the upper lid body 7 is formed with a liquid injection port 7b which is threaded for injecting an electrolytic solution, and a liquid injection stopper 15 is fixed by screws. Reference numeral 7 c denotes a positive electrode terminal formed integrally with the upper lid body 7.

  As shown in FIG. 1, a safety valve 13 that discharges internal gas in response to a rise in internal pressure is also caulked and fixed to the lower lid 4 via a safety valve spacer 14. Further, the lower lid body 4 is formed with an engaging recess 4a into which the protruding portion 3a of the core 3 is fitted.

  Next, the assembly process of the unit cell 1 having the above configuration will be described. As shown in FIG. 3 and FIG. 4, the upper lid body 7 is inserted into one opening of the outer case 2 and arranged so that the end faces are the same, and the boundary between the outer case 2 and the upper lid body 7 is welded. Join. Further, the negative electrode current collector plate 6 and the positive electrode current collector plate 16 are passed through the projecting portions 3a at both ends of the core 3 through the respective openings 6b and 16b on both end surfaces of the electrode plate group 5 wound around the core 3. Abuttingly arranged, and further, welding is joined in a state where the protrusions 6a and 16a are pressed. In this state, the rising piece 6c of the negative electrode current collector plate 6 is fitted in the concave portion 3b on one side surface of the protruding portion 3a, and the connecting plate portion of the negative electrode terminal 11 is inserted into the concave portion 3b of the protruding portion 3a of the winding core 3. A part of 11 a is fitted, and the protruding part 3 a, the rising piece 6 c and the connecting plate part 11 a are caulked and fixed by the connecting member 17. Next, after attaching the lower insulating ring 8 to the negative electrode terminal 11, the electrode plate group 5 is inserted and accommodated in the outer case 2, and the negative electrode terminal 11 is inserted and fitted into the cylindrical hole 7 a of the upper lid body 7.

  Next, the rising pieces 16c formed to rise on both sides of the positive electrode current collector plate 16 of the electrode plate group 5 are brought into close contact with the inner surface of the outer case 2 and joined by welding, and then the other opening of the outer case 2 is opened. The lower lid body 4 is inserted into the part, arranged so that the end faces are the same, and the boundary between the outer case 2 and the lower lid body 4 is joined by welding.

  Next, an O-ring 9 is attached to the negative electrode terminal 11 inserted into the cylindrical hole 7a formed in the upper lid 7, and is press-fitted into the gap between the cylindrical hole 7a and the negative electrode terminal 11, and the upper insulating ring 10 is inserted and disposed. After that, the fixing ring 12 is mounted and fixed in the fixing groove 11 c of the negative electrode terminal 11. Next, a predetermined amount of electrolytic solution is injected from the liquid injection port 7 b of the upper lid body 7 to impregnate the electrode plate group 5, and then sealed with a liquid injection plug 15 to complete the unit cell 1.

  According to the above embodiment, the electrode plate group 5 is configured using the winding core 3 as a winding axis, and the positive electrode current collector plate 16 and the negative electrode current collector plate 6 are welded to the end face of the electrode plate group 5, Since the negative electrode terminal 11 is connected and fixed to the winding core 3 together with the negative electrode current collector plate 6 by the connecting member 17, the electrode plate group 5 is fixed to the outer case 2 via the winding core 3. The secondary battery 1 having resistance to vibration and impact in the direction and the front-rear direction can be obtained. In addition, since the negative electrode terminal 11 is fixed to the core 3 together with the negative electrode current collector plate 6 by caulking of the connecting member 17, it is possible to realize a simple and low processing cost assembly and to reduce the number of assembling steps.

  In the secondary battery of the present invention, the electrode plate group and the current collector plate are restrained in the battery by the core of the electrode plate group and the electrode terminal fixed to the core together with the current collector plate. It is useful for high-power lithium secondary batteries for electric tools, cordless vacuum cleaners, electric vehicles, and the like that are required to have high resistance.

It is a vertical front view of the secondary battery of one Embodiment of this invention. It is a vertical side view of the secondary battery of the same embodiment. It is a disassembled perspective view of the secondary battery of the same embodiment. It is a detailed perspective view of the negative electrode terminal part of the secondary battery of the same embodiment. It is a vertical front view of the secondary battery of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Secondary battery 2 Outer case 3 Winding core 3a Protruding part 3c Hole 4 Lower cover body 5 Electrode board group 6 Negative electrode current collection board 6b Opening 6d Hole 7 Upper cover body 8 Lower insulating ring 10 Upper insulating ring 11 Negative electrode terminal (electrode terminal)
11b hole 16 positive electrode current collector plate 16b opening 17 connecting member

Claims (5)

  The positive electrode plate and the negative electrode plate are opposed to each other with a separator interposed between them, and are wound around a winding core as an axis, and the core material to which the mixture layer of the positive electrode plate is not applied is exposed on one end face in the width direction. An electrode plate group in which a core material to which the mixture layer of the negative electrode plate is not applied is exposed on the other end surface, a positive electrode current collector plate bonded to one end surface of the electrode plate group, and the electrode plate group A negative electrode current collector plate joined to the other end surface, an electrode terminal fixed to the winding core together with one of the current collector plates together with a connecting member, an outer case housing the electrode plate group, and the outer case A secondary battery comprising: a lid that seals the opening and fixes the electrode terminal through an insulating member; and an electrolytic solution impregnated in the electrode plate group.   The secondary battery according to claim 1, wherein the current collector is fixed by caulking of a connecting member in a state where a current collector plate is sandwiched between the electrode terminal and the core.   The secondary battery according to claim 1, wherein a protrusion is formed at an end of the core, and an opening through which the protrusion is inserted is formed in a current collector plate.   The secondary battery according to claim 1, wherein the electrode terminal, the current collector plate, and the core are provided with a plurality of holes through which the connection member passes.   The secondary battery according to any one of claims 1 to 4, wherein the outer case has a cylindrical shape with openings at both ends, and both ends thereof are sealed with lids.

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