JP2012195138A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery having excellent sealing properties at a portion where an outer jacket and an external terminal are fixed to each other.SOLUTION: A battery 10 comprises an outer jacket 30, an external terminal 40, an insulating member 50, a burring portion 34 disposed on the periphery of a through hole 33 of a lid 32 of the outer jacket 30, and projecting in the outward direction of the outer jacket 30, and a restraint ring 35 disposed on the outer circumference of the burring portion 34. The external terminal 40 is fixed to the lid 32 by pressing the burring portion 34. The insulating member 50 is composed of a material having a bending modulus of elasticity low enough to inhibit outward plastic deformation in the radial direction from the through hole 33 while the burring portion 34 is being pressed.

Description

  The present invention relates to a battery, and more particularly to a technique for fixing an external terminal to an exterior.

In Patent Document 1, in a battery in which an external terminal protrudes from an outer cover part, an insulating member is interposed between the cover part and the external terminal, and a burring part is provided around the insulating member in the cover part. A technique for fastening and fixing an external terminal by pressing and crimping a burring portion from a direction orthogonal to the protruding direction of the portion is disclosed.
When the battery is a non-aqueous electrolyte battery such as a lithium ion secondary battery, it is known that battery performance is affected when moisture enters the battery. For this reason, it is necessary to maintain the battery sealing property sufficiently high.

  However, when the cooling / heating cycle is repeated with repeated use of the battery, the caulking fastening part gradually loosens due to the action of trying to return to the shape before caulking, the sealing performance deteriorates, and the exterior and The sealing performance of the fixed part of the external terminal may be insufficient.

JP 2005-302625 A

  An object of the present invention is to provide a battery excellent in sealing performance at a fixing portion between an exterior and an external terminal in a battery that fixes the external terminal in a state of penetrating the exterior and protruding outward.

  The battery of the present invention includes an exterior having a lid portion in which a through hole is formed, an external terminal fixed to the through hole in a state in which a part projects outward from the lid portion, and the lid portion and the outside Consists of an insulating member interposed between terminals, a burring portion located at the periphery of the through-hole of the lid portion and projecting outward from the lid portion, and a material having higher strength than the lid portion And a restraining member disposed on the outer periphery of the burring portion, and pressing the protruding side end surface of the burring portion to cause plastic deformation from the inner peripheral surface of the through-hole to the inner side. A battery that fixes the external terminal to the through hole by generating a compression force between the external terminal and the through hole through the insulating member by a part of the burring portion, wherein the insulating member is When the burring part is pressed, the through hole Constructed of a material having a low flexural modulus of enough to suppress plastic deformation of the Luo radially outward.

  The cover part of the exterior is made of A1000 series aluminum, and the insulating member is made of a super engineering plastic or elastomer containing super engineering plastic having a flexural modulus of 0.66 GPa or more and 3.1 GPa or less. preferable.

  It is preferable that an R portion is formed at the battery inner end portion of the burring portion.

  It is preferable that the insulating member is compressed in a circular arc shape in a sectional view by a part of the plastically deformed burring portion.

  ADVANTAGE OF THE INVENTION According to this invention, the battery excellent in the sealing performance in the fixing | fixed part of an exterior and an external terminal can be provided.

It is a figure which shows schematic structure of a battery. It is an expanded sectional view which shows the fixing | fixed part of an exterior and an external terminal. It is a figure which shows the change of the external dimension by deformation | transformation of a cover part. It is a figure which shows the correlation with the constituent material and deformation | transformation of a cover part. It is a figure which shows the R part formed in the base end part of a burring part. It is a figure which shows another form of the fixing | fixed part of an exterior and an external terminal. It is a figure which shows another form of the fixing | fixed part of an exterior and an external terminal. It is a figure which shows the preferable compression form of an insulating member.

With reference to FIG. 1, a schematic configuration of a battery 10 which is an embodiment of the battery according to the present invention will be described. The battery 10 of this embodiment is a lithium ion secondary battery, and is a nonaqueous electrolyte battery.
The battery 10 includes a power generation element 20, an exterior 30 that houses the power generation element 20, external terminals 40, 40 that protrude outward from the exterior 30, and an external terminal 40, 40 and an exterior 30. Insulating members 50 and 50 to be mounted.

  The power generation element 20 is obtained by impregnating an electrolytic solution into an electrode body formed by laminating or winding a positive electrode, a negative electrode, and a separator. When the battery 10 is charged / discharged, a chemical reaction occurs in the power generation element 20 (strictly speaking, ion movement occurs between the positive electrode and the negative electrode via the electrolytic solution), thereby generating a current flow.

The exterior 30 is a square can having a storage portion 31 and a lid portion 32. The storage unit 31 is a bottomed cylindrical member having an open surface, and stores the power generation element 20 therein. The lid portion 32 is a flat member having a shape corresponding to the opening surface of the storage portion 31 and is joined to the storage portion 31 in a state where the opening surface of the storage portion 31 is closed.
The lid portion 32 has through holes 33 and 33 through which the external terminals 40 and 40 can pass. The through hole 33 is a hole having a predetermined inner diameter, and penetrates in the thickness direction of the lid portion 32.

The external terminals 40 and 40 are arranged in a state where a part of the external terminals 40 protrudes outward from the battery 10 from the outer surface of the lid portion 32. The external terminals 40 and 40 are electrically connected to the positive electrode or the negative electrode of the power generation element 20 via current collecting terminals 45 and 45. The external terminals 40 and 40 and the current collecting terminals 45 and 45 function as an energization path for taking out the electric power stored in the power generation element 20 to the outside or taking in electric power from the outside into the power generation element 20.
Each current collecting terminal 45 is connected to the positive electrode plate and the negative electrode plate of the power generation element 20. As a material of the current collecting terminal 45, for example, aluminum can be used on the positive electrode side and copper on the negative electrode side.

  The external terminal 40 is threaded by thread rolling at a portion protruding outward of the battery 10 to form a bolt portion. When the battery 10 is actually used, a bus bar, a connection terminal of an external device, and the like are fastened and fixed to the external terminal 40 using the bolt portion. When fastening and fixing, since external torque is applied to the external terminal 40 and external force is applied in the axial direction by screw fastening, it is preferable to employ a high-strength material such as iron as the material of the external terminal 40.

  The external terminals 40 and 40 are fixed to the lid portion 32 through insulating members 50 and 50. The insulating member 50 is a resin member and is wound around the external terminal 40 to electrically insulate the exterior 30 from the external terminal 40. Moreover, the edge part of the insulating member 50 is extended between the current collection terminal 45 and the cover part 32, and insulates between these electrically.

  Below, with reference to FIG. 2, the fixed form of the exterior | packing 30 and the external terminal 40 is demonstrated.

  As shown in FIG. 2A, a burring portion 34 that protrudes toward the outside of the exterior 30 is formed at the periphery of each through-hole 33 of the exterior 30. The burring part 34 is a thick portion formed by plastic processing a part of the exterior 30 and is appropriately formed by a known burring process, a deep drawing method, a close-up method, or a combination thereof.

A restraining ring 35 is disposed on the outer periphery of the burring portion 34.
The restraining ring 35 is a ring-shaped member manufactured with a material having a strength higher than that of the material constituting the exterior 30 (the lid portion 32). By restraining the burring portion 34 from the outer peripheral side, the diameter of the burring portion 34 is increased. Reinforce direction strength. The inner diameter of the restraining ring 35 is substantially the same as the outer diameter of the burring portion 34.

  In addition, an airtight groove 41 is formed in the midway portion in the axial direction on the outer peripheral side surface of the external terminal 40. The airtight groove 41 is a semicircular (or semi-elliptical, triangular, etc.) concave portion formed over the entire outer periphery along the circumferential direction of the external terminal 40, and has edge lines at both ends of the groove. . The airtight groove 41 has a predetermined groove width.

As shown in FIG. 2B, the external terminal 40 around which the insulating member 50 is wound is disposed in the through hole 33, the restraining ring 35 is disposed around the burring portion 34, and the protruding side end surface of the burring portion 34 is arranged. By pressing and caulking the inner peripheral portion, a part of the burring portion 34 is plastically deformed to form a bulging portion 34a that bulges radially inward from the inner peripheral side surface.
At this time, the presence of the high-strength material restraining ring 35 on the outer peripheral side of the burring portion 34 prevents the pressing force during caulking from escaping and works toward the inside in the radial direction. Thereby, it forms so that the bulging part 34a may bulge inwardly reliably.

The bulging portion 34 a bulging inwardly presses the insulating member 50, and this pressing force is applied as a surface pressure to the insulating member 50. A portion of the insulating member 50 to which the surface pressure is applied by the bulging portion 34 a is elastically deformed inward, and an external force generated by the elastic deformation is applied as a surface pressure to the external terminal 40.
In this way, compression force is applied to the external terminal 40 and the insulating member 50, respectively, and the external terminal 40 and the insulating member 50 are fixed to the through hole 33 of the lid portion 32. In particular, when the insulating member 50 enters the airtight groove 41 and bites into the edge line, the airtightness between the insulating member 50 and the external terminal 40 is ensured.

  At this time, since the bulging portion 34a is plastically deformed in a direction orthogonal to the pressing direction and fastens and fixes the insulating member 50 and the external terminal 40, the space between the exterior 30, the insulating member 50, and the external terminal 40 is fixed. It is possible to apply a strong surface pressure and frictional force. Therefore, even if it receives the cooling / heating cycle at the time of using the battery 10, the bulging part 34a is hard to deform | transform and a fixing | fixed part does not loosen easily.

Hereinafter, the constituent material of the insulating member 50 will be described with reference to FIGS. 3 and 4.
As described above, the insulating member 50 ensures the insulation between the exterior 30 and the external terminal 40 and also ensures the sealing performance of the battery 10. For this reason, a material that is excellent in high-temperature creep characteristics, that is, a material that has long-term creep resistance to the cooling cycle of the battery 10 is preferable. In addition, since the insulating member 50 is in contact with the electrolytic solution inside the exterior 30, it requires high resistance to the solvent contained in the electrolytic solution.
Based on the above, a resin such as PPS (polyphenylene sulfide) or PFA (perfluoroalkoxy fluororesin) is applicable as the material of the insulating member 50.

On the other hand, as the material property of the insulating member 50, the greater the flexural modulus, the greater the pressing force from the bulging portion 34a in order to compress the insulating member 50 and ensure sealing performance. For this purpose, it is necessary to increase the amount of press on the burring portion 34 and increase the amount of deformation of the burring portion 34.
For example, as shown in FIG. 3, by increasing the amount of pressing and increasing the amount of deformation of the burring portion 34, it is possible to compress against the reaction force from the insulating member 50 and ensure sealing performance. However, a reaction force is received from the insulating member 50 against the deformation of the burring portion 34 (the bulging of the bulging portion 34a), and plastic deformation occurs radially outward of the through hole 33, so that the end of the lid portion 32 It may be deformed. When the end portion of the lid portion 32 is deformed, the outer dimension of the lid portion 32 changes. When manufacturing the battery 10, the lid portion 32 is joined to the storage portion 31, and the interior of the exterior 30 is used as a sealed space. Therefore, if the external dimensions change, there is a problem in joining the lid portion 32 and the storage portion 31. As a result, the airtightness of the exterior 30 may be insufficient.

Therefore, in the present embodiment, the material of the insulating member 50 is determined so as not to be deformed in the extending direction of the lid portion 32 when the burring portion 34 is pressed while ensuring the sealing performance of the battery 10. That is, the material of the insulating member 50 is determined in consideration of the strength of the lid portion 32 and the pressing conditions for the burring portion 34.
In other words, when the burring part 34 is pressed under the pressing conditions necessary to ensure the sealing property of the battery 10, plastic deformation outward (outward from the burring part 34) in the radial direction is suppressed, and the lid A material having a bending elastic modulus that does not change the external dimensions (outer dimensions in the short-side direction and the long-side direction) of the portion 32 is adopted as a constituent material of the insulating member 50.

In the case where A1000 series pure aluminum is used as the material of the cover part 32, the relationship between the deformation in the planar direction of the cover part 32 (change in the external dimensions) that occurs when pressing the burring part 34 and the material of the insulating member 50 is as follows. Examined. In addition, the burring part 34 shall be pressed according to the press conditions which can ensure the sealing performance in the fixing part of the external terminal 40 and the exterior 30.
As a result, as shown in FIG. 4, in the natural PEEK (flexural modulus: 10 [GPa]) and natural PPS (flexural modulus: 3.9 [GPa]), the lid portion 32 is deformed, and the elastomer 5 vol. % Containing PPS (flexural modulus: 3.1 [GPa]), elastomer 20 vol% containing PPS (flexural modulus: 1.8 [GPa]), natural PFA (flexural modulus: 0.66 [GPa]), There was no change in the external dimensions of the lid portion 32.
The natural PEEK, natural PPS, and natural PFA refer to pure PEEK materials, PPS materials, and PFA materials that do not contain elastomers, with or without elastomers.

From the above, when a material having a large flexural modulus (here, a super engineering plastic of 3.9 GPa or more) is used as a constituent material of the insulating member 50 without considering the strength of the lid portion 32, As the reaction force increases and the burring portion 34 is pressed, the bulging portion 34a is not only plastically deformed radially inward, but is also plastically deformed radially outward to form the outer shape of the lid portion 32. It can be seen that the dimensions change.
When the material of the lid portion 32 is A1000 series pure aluminum, the material of the insulating member 50 is a super engineering plastic or elastomer containing super engineering plastic having a flexural modulus of 0.66 GPa or more and 3.1 GPa or less. Preferably, by adopting PPS or natural PFA containing 5 vol% or more of elastomer, it is possible to satisfy the conditions that do not cause deformation of the outer shape of the lid portion 32 at the time of caulking, while ensuring the sealing performance of the battery 10. confirmed. This is because the strength of the cover portion 32 of A1000 series aluminum is large enough for the surface pressure required when the cover portion 32 is plastically deformed to compress the insulating member 50 having a predetermined bending elastic modulus. Means.

As shown in FIG. 5, an R portion is formed at a connection portion between the lid portion 32 and the burring portion 34, that is, at a base end portion (battery inner end portion) of the burring portion 34.
When the insulating member 50 is disposed around the external terminal 40 and inserted into the through hole 33 of the lid portion 32, the base end portion of the burring portion 34 and the insulating member are formed due to the presence of the R portion formed in the burring portion 34. A gap is formed between the outer surface and the outer surface.

  Hereinafter, with reference to FIGS. 6 and 7, the handling of the R portion at the base end of the burring portion 34 in the fixing portion of the exterior 30 and the external terminal 40 will be described.

In the embodiment shown in FIG. 6, the constraining ring 35 is disposed outside the burring portion 34, and the insulating member 50 is insert-molded in a state where the external terminals 40 are disposed, whereby the R portion of the burring portion 34 and the insulating member 50. And filling the gap. In addition, the gap between the R portion of the burring portion 34 and the insulating member 50 is filled, and at the same time, the gap between the external terminal 40 and the insulating member 50 is filled, so that the insulating member 50 firmly enters the airtight groove 41.
Thereby, even if the R portion is formed at the boundary portion between the lid portion 32 and the burring portion 34, the pressing force does not escape to the gap between the burring portion 34 and the insulating member 50 when pressing the burring portion 34. The bulging portion 34 a can be deformed in the compression direction of the insulating member 50, and the pressing force of the press can be utilized as much as the compression force to the insulating member 50. In addition, by embedding the insulating member 50 in the airtight groove 41, the degree of adhesion between the insulating member 50 and the external terminal 40 can be improved, and the sealing performance can be improved.

In the embodiment shown in FIG. 7, the R portion is plastically deformed at the time of pressing the burring portion 34 to release the deformation of the lid portion 32 in the plane direction, and the reaction force from the insulating member 50 is released to the R portion. Yes. That is, as one of the deformation directions by pressing the burring portion 34, the lid portion is included by allowing the deformation of the lid portion 32 due to the reaction force from the insulating member 50 to escape to the gap by including the gap formed by the R portion. The deformation | transformation to the plane direction of 32 is suppressed.
As described above, it is possible to suppress the deformation in the planar direction of the lid portion 32 due to the pressing to the burring portion 34, and it is possible to increase the materials that can be adopted by relaxing the conditions regarding the bending elastic modulus of the insulating member 50. That is, in the present embodiment, the R portion of the base end portion of the burring portion 34 is plastically deformed into the gap with the insulating member 50 caused by the presence of the R portion, thereby absorbing the deformation in the planar direction of the lid portion 32. The deformation due to the reaction force from the insulating member 50 is absorbed.
In addition, since the deformation by the reaction force of the insulating member 50 can be absorbed by absorbing a part of the deformation of the burring portion 34 by the R portion in this way, the bending elastic modulus of the constituent material of the insulating member 50 is the above-mentioned maximum. It is also possible to use a material larger than the value (3.1 [GPa]).

Moreover, as shown in FIG. 8, it is preferable that the bulging portion 34a bulges out in an arc shape in cross section. That is, the bulging portion 34a bulges so as to form a curved surface having a substantially similar shape (arc shape) to the surface of the airtight groove 41 formed in a semicircular shape, and compressing the insulating member 50 into an arc shape, The compression shape of the insulating member 50 is preferably an arc shape in cross-section.
According to this, as shown in FIG. 8B, even when an external force is applied to the external terminal 40 and the external terminal 40 is inclined in the axial direction, the arc-shaped bulging surface of the bulging portion 34a is substantially uniform. The pressure does not act on the compression force, and the compression force is not greatly reduced. Furthermore, the state in which the insulating member 50 compressed in an arc shape is engaged with the edge line on the inner side or the outer side of the airtight groove 41 is maintained. For this reason, the compressibility to the insulating member 50 does not decrease, and the sealing performance of the battery 10 is maintained.

DESCRIPTION OF SYMBOLS 10 Battery 30 Exterior 33 Through-hole 34 Burring part 35 Restraint ring (restraint member)
40 External terminal 41 Airtight groove (recess)
50 Insulating material

Claims (4)

An exterior having a lid in which a through hole is formed;
An external terminal fixed to the through hole in a state in which a part protrudes outward from the lid,
An insulating member interposed between the lid and the external terminal;
A burring portion located at the periphery of the through-hole of the lid portion and projecting outward of the lid portion;
A constraining member arranged on the outer periphery of the burring portion, and made of a material stronger than the lid portion,
The protruding end surface of the burring portion is pressed and plastically deformed inward from the inner peripheral surface of the through hole, and the external terminal and the through hole are interposed via the insulating member by a part of the plastically deformed burring portion. A battery that fixes the external terminal to the through hole by generating a compression force between
The battery is formed of a material having a bending elastic modulus that is low enough to suppress plastic deformation from the through hole to the radially outer side when pressing the burring portion. The exterior lid is made of A1000 series aluminum,
The battery according to claim 1, wherein the insulating member is made of a super engineering plastic or an elastomer-containing super engineering plastic having a flexural modulus of 0.66 GPa or more and 3.1 GPa or less.   The battery according to claim 1, wherein an R portion is formed at a battery inner end portion of the burring portion.   The battery according to any one of claims 1 to 3, wherein the insulating member is compressed in a circular arc shape in cross section by a part of the plastically deformed burring portion.

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