JP2018147681A - Sealed battery and electrode terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed battery having an electrode terminal capable of suitably restraining rotation of a bolt by properly fitting a fitting part of the bolt with a bolt fitting part of an insulation member.SOLUTION: An electrode terminal 30 of a sealed battery according to the present invention comprises: a collector member 32 exposed to outside of a case 10; a bolt 34 on which a columnar connection part 34a connected to an external device and a fitting part 34b that is a square-shaped convex part are formed; a plate-like external connection member 36 for electrically connecting the collector member 32 and the bolt 34; and an insulation holder 38 that is an insulation member arranged between the external connection member 36 and the case 10, and on which a bolt housing part 38a that is a square-shaped convex part fitted with the fitting part 34b of the bolt 34 is formed. In the sealed battery according to the present invention, a concave-shaped dimension absorbing part 38d is formed on a bottom face of the bolt housing part 38a.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sealed battery and an electrode terminal used for the sealed battery.

Secondary batteries such as lithium ion secondary batteries and nickel metal hydride batteries are becoming increasingly important as on-vehicle power supplies or personal computers and portable terminals. Such a secondary battery is constructed, for example, as a sealed battery in which an electrode body together with an electrolyte substance is sealed in a case.
The case of such a sealed battery is provided with electrode terminals. Such electrode terminals can be used for various purposes such as connecting a plurality of sealed batteries to each other to construct an assembled battery or connecting to a vehicle motor or the like. Used when connecting to external equipment. For example, an assembled battery composed of a plurality of batteries can be constructed by arranging two or more sealed batteries adjacent to each other and connecting the electrode terminals of each battery via a bus bar. A technique related to a sealed battery provided with such an electrode terminal is described in Patent Document 1.

An example of a sealed battery provided with such an electrode terminal is shown in FIG. A sealed battery 100 shown in FIG. 1 includes a flat rectangular case 10, and an electrode body 20 is accommodated in the case 10. The case 10 includes a flat rectangular case main body 12 having an upper surface opened, and a lid 14 that closes the opening on the upper surface of the case main body 12. A negative electrode terminal 30 is provided.
Each electrode terminal 30 includes a current collecting member 32, a bolt 34, and an external connection member 36. One end 32 a of the current collecting member 32 is connected to the electrode body 20 in the case 10, and the other end 32 b is exposed outside the case 10. Further, the bolt 34 includes a columnar connection portion 34a that is electrically connected to the external device. In the electrode terminal 30, the current collecting member 32 and the bolt 34 are electrically connected by a plate-like external connection member 36. In addition, in this electrode terminal 30, an insulating holder 38 is disposed between the external connection member 36 and the lid body 14 in order to prevent each member described above from energizing the case 10 (lid body 14). Yes.

In such an electrode terminal 30, the connection part 34 a of the bolt 34 and the external device are connected by tightening a nut or the like, but if the bolt 34 is provided at this time, a connection failure may occur between the external device and the external terminal. There is.
In order to prevent poor connection due to the rotation of the bolt, the above-described insulating holder 38 is provided with a bolt housing portion that restricts the rotation of the bolt 34. Specifically, as shown in FIG. 2, a rectangular fitting portion 34b is formed at the lower end of the bolt 34, and the upper surface of the insulating holder 38 has dimensions corresponding to the fitting portion 34b. A bolt housing portion 38a which is a rectangular recess having The rotation of the bolt 34 is restricted by fitting the fitting portion 34b of the bolt 34 and the bolt storage portion 38a of the insulating holder 38, and the bolt 34 is prevented from being rotated when connected to an external device. Is done.

Japanese Patent No. 4985840

  However, in the sealed battery 100 having the above-described structure, the shape and dimensions of each member are designed so that the fitting portion 34b of the bolt 34 and the bolt storage portion 38a of the insulating holder 38 are fitted without a large gap. In spite of this, the rotation of the bolt 34 may occur when connecting to an external device.

As a result of the inventor's investigation of the cause of the rotation of the bolt 34, when the electrode terminal 30 of the sealed battery 100 is connected to an external device, the insulating holder 38 expands and the side wall 38b of the bolt storage portion 38a. It has been found that a gap may be formed between the bolt 34 and the fitting portion 34b of the bolt 34, and in this case, the rotation of the bolt 34 cannot be properly regulated.
Specifically, in the general sealed battery 100, the bolt 34 of the electrode terminal 30 and the external device are connected by tightening a nut or the like as described above. Frictional heat generated during connection may be transmitted to the insulating holder 38. When the temperature of the insulating holder 38 rises due to such frictional heat at the time of tightening the nut or temperature change in the external environment, as shown in FIG. 11, outward thermal stress B is generated on the bottom surface of the bolt housing portion 38a. The space between the side walls 38b may be increased by the expansion of the bolt housing portion 38a.
The inventor considered that the expansion of the insulating holder 38 due to frictional heat or the like described above is a cause that the rotation of the bolt 34 cannot be regulated despite the appropriate design of the dimensions of each member.

  The present invention has been made on the basis of such knowledge, and its main purpose is to suppress the expansion of the insulating holder due to frictional heat and the like so that the fitting portion of the bolt and the bolt fitting portion of the insulating member are made. It is an object of the present invention to provide a sealed battery having an electrode terminal that can be properly fitted and can appropriately regulate the rotation of a bolt.

  In order to achieve the above object, the present invention provides a sealed battery having the following configuration.

The sealed battery disclosed here is configured by housing an electrode body in a case, and an electrode terminal connected to an external device is provided in the case.
The electrode terminal in such a sealed battery has a current collecting member having one end electrically connected to the electrode body in the case and the other end exposed to the outside of the case, and one end. A bolt-shaped connecting part formed with a columnar connecting part connected to an external device at the part and a fitting part which is a square convex part at the other end, and the current collecting member and the bolt are electrically connected A plate-like external connection member connected to the base plate and an insulating member disposed between the external connection member and the case, and a bolt housing portion which is a square recess to be fitted with the fitting portion of the bolt is formed. And an insulated holder.
And in the sealed battery disclosed here, the concave dimension absorption part is formed in the bottom face of the volt | bolt accommodating part.

The insulation holder of the sealed battery disclosed here has a concave dimension absorbing portion formed on the bottom surface of the bolt housing portion. In such an insulating holder, the bottom surface of the bolt housing portion contracts toward the dimension absorbing portion, and residual stress is generated toward the dimension absorbing portion (that is, toward the inside of the bolt housing portion). For this reason, even if a thermal stress directed outward is generated on the bottom surface of the bolt housing portion due to frictional heat or the like when connected to an external device, the thermal stress can be reduced by the residual stress toward the dimension absorbing portion. Expansion of the bottom surface of the storage unit can be suppressed.
As described above, according to the sealed battery disclosed herein, since the thermal expansion of the bottom surface of the bolt holder of the insulating holder can be suppressed, the fitting portion of the bolt and the bolt holder of the insulating holder can be fitted without a gap. Thus, the rotation of the bolt can be suitably restricted, and the occurrence of poor connection due to the rotation of the bolt can be prevented.

In a preferred embodiment of the sealed battery disclosed herein, the dimension absorbing portion is formed in the vicinity of the center portion of the bottom surface of the bolt housing portion.
By providing the dimension absorbing portion near the center of the bottom surface of the bolt housing portion as in this aspect, the residual stress toward the dimension absorbing portion can be uniformly generated on the bottom surface of the bolt housing portion. Thereby, the thermal expansion of the bolt housing portion can be more suitably suppressed, and the rotation of the bolt can be restricted.

In a preferred embodiment of the sealed battery disclosed herein, two or more dimension absorbing portions are formed on the bottom surface of the bolt housing portion.
By providing a plurality of dimension absorbing portions in this manner, a sufficient residual stress can be generated on the bottom surface of the bolt housing portion, so that the thermal expansion of the bolt housing portion can be appropriately suppressed.

Moreover, in another preferable aspect of the sealed battery disclosed herein, the shape of the dimension absorbing portion in plan view is any one of a circle, an ellipse, and a rectangle.
Although the shape of the dimension absorbing portion in plan view is not particularly limited, it is preferable that the residual stress toward the dimension absorbing portion can be suitably generated and can be easily formed on the bottom surface of the bolt storage portion. , Oval or rectangular.

Moreover, in another preferable aspect of the sealed battery disclosed herein, the shape of the dimension absorbing portion in a plan view is circular, and the diameter of the planar circular dimension absorbing portion is 1 mm to 1.5 mm.
It is preferable that the dimension of the dimension absorbing part is appropriately adjusted in consideration of the material of the insulating holder, the dimension of the bolt storage part, and the like. For example, if the dimension absorbing portion is too small with respect to the bolt housing portion, it is difficult to generate sufficient residual stress on the bottom surface of the bolt housing portion. Similarly, when the dimension absorbing portion is too large, the residual stress in the bolt housing portion may be reduced. For example, when the shape of the dimension absorbing portion in plan view is circular, the diameter of the planar circular dimension absorbing portion is preferably set within a range of 1 mm to 1.5 mm.

Moreover, in another preferable aspect of the sealed battery disclosed herein, the depth of the dimension absorbing portion is 0.5 mm to 2.5 mm.
When the dimension absorbing portion is deepened, the residual stress generated on the bottom surface of the bolt housing portion is increased, and the thermal expansion of the bolt housing portion can be more suitably suppressed. On the other hand, when the depth is too deep, the durability of the insulating holder is lowered. There is a fear. For this reason, it is preferable to appropriately adjust the depth of the dimension absorbing portion in consideration of the strength of the insulating holder and the like. Note that if the dimension absorbing part is formed so as to penetrate the insulating holder, there is a possibility that the bolt and the lid may be energized when conductive foreign matter such as metal powder enters the dimension absorbing part. The depth is preferably set so as not to penetrate the insulating holder.

Moreover, this invention provides the electrode terminal used for an above-described sealed battery as one side surface for solving the said subject.
The electrode terminal has a current collecting member having one end electrically connected to the electrode body in the case and the other end exposed to the outside of the case, and an external device at one end. A plate that electrically connects the current collector and the bolt, with a columnar connection portion connected to the bolt and a fitting portion that is a square convex portion formed at the other end An external connection member, and an insulation member disposed between the external connection member and the case, in which a bolt housing portion that is a square recess to be fitted with the fitting portion of the bolt is formed And a holder.
And in the electrode terminal disclosed here, the concave dimension absorption part is formed in the bottom face of a bolt accommodating part, and the residual stress which goes to the dimension absorption part has arisen in the bottom face of the said bolt accommodating part.

  According to the electrode terminal having such a configuration, even when the temperature of the insulating holder is increased due to frictional heat generated in connection with an external device, the bolt housing portion of the insulating holder can be appropriately suppressed from expanding, The rotation of the bolt is preferably restricted, and the occurrence of poor connection due to the rotation of the bolt can be prevented.

It is a perspective view which shows a sealed battery typically. It is a disassembled perspective view of the electrode terminal of the sealed battery shown in FIG. It is sectional drawing which shows typically the structure of the electrode terminal vicinity of the sealed battery which concerns on one Embodiment of this invention. It is a figure which shows typically the insulation holder used for the electrode terminal of the sealed battery which concerns on one Embodiment of this invention, Fig.4 (a) is a perspective view, FIG.4 (b) is a top view, FIG.4 (c) ) Is a cross-sectional view taken along the line CC in FIG. It is a top view which shows typically the volt | bolt accommodating part vicinity of the insulation holder in one Embodiment of this invention. It is a top view which shows typically the volt | bolt accommodating part vicinity of the insulation holder in other embodiment of this invention. It is a top view which shows typically the volt | bolt accommodating part vicinity of the insulation holder in other embodiment of this invention. It is a top view which shows typically the volt | bolt accommodating part vicinity of the insulation holder in other embodiment of this invention. It is a top view which shows typically the volt | bolt accommodating part vicinity of the insulation holder in other embodiment of this invention. It is a graph which shows the dimensional change of the bolt accommodating part of the test example 1 and the test example 2. FIG. It is a top view which shows typically the bolt accommodating part vicinity of the conventional insulation holder.

  Hereinafter, a lithium ion secondary battery will be described as an example of a sealed battery according to an embodiment of the present invention. The sealed battery disclosed here is not limited to a lithium ion secondary battery, and may be, for example, a nickel metal hydride battery.

  Moreover, in the following drawings, the same code | symbol is attached | subjected and demonstrated to the member and site | part which show | plays the same effect | action. In addition, the dimensional relationship (length, width, thickness, etc.) in each drawing does not reflect the actual dimensional relationship. Further, matters other than matters specifically mentioned in the present specification and matters necessary for the implementation of the present invention (for example, general construction related to the construction of a lithium ion secondary battery such as an electrode body and an electrolyte substance and a manufacturing method thereof) Technical technology etc.) can be understood as a design matter of those skilled in the art based on the prior art in the field.

1. Overall Configuration The basic structure of a sealed battery according to this embodiment is the same as that of a conventional sealed battery. Specifically, as shown in FIG. 1, the sealed battery 100 according to this embodiment is configured by housing an electrode body 20 in a flat rectangular case 10. The case 10 of the sealed battery 100 includes a flat rectangular case main body 12 having an open upper surface and a plate-like lid body 14 that closes the opening on the upper surface of the case main body 12. Such a case 10 is preferably composed mainly of a metal material that is lightweight and has good thermal conductivity. Examples of such a metal material include aluminum.

The electrode body 20 accommodated in the case 10 includes positive and negative electrodes in which a composite layer containing an electrode active material capable of occluding and releasing lithium ions is provided on the surface of a foil-shaped current collector.
In the present embodiment, a wound electrode body is used as the electrode body 20. Although not shown in the drawings, the wound electrode body 20 is provided on the surface of a foil-like positive electrode current collector, a long sheet-like positive electrode provided with a positive electrode mixture layer on the surface of the foil-like positive electrode current collector, and the surface of the foil-like negative electrode current collector. It is formed by laminating these positive and negative electrodes through a separator and winding the laminate. A wound core portion 20A is formed at the center of the wound electrode body 20 in the width direction X so that the positive and negative electrode mixture layers are opposed to each other. A terminal connection portion 20B is formed in which a current collector not provided with a material layer is wound.
In the sealed battery 100 according to the present embodiment, the material of each member (for example, the positive electrode, the negative electrode, and the separator) constituting the electrode body 20 is the same as that used for a conventional general lithium ion secondary battery. The present invention can be used without limitation, and does not characterize the present invention.

  In addition, the case 10 of the sealed battery 100 according to the present embodiment contains an electrolyte substance together with the electrode body 20 described above, and this electrolyte substance is also a conventional general lithium ion secondary battery. Since the same thing as can be used without particular limitation, detailed description is omitted.

In the sealed battery 100 according to this embodiment, the electrode terminal 30 is provided on the lid 14 that forms the upper surface of the case 10. The electrode terminal 30 is used when a plurality of sealed batteries are connected to construct an assembled battery, or when connected to a vehicle motor or the like. Specifically, the electrode terminal 30 is electrically connected to the electrode body 20 in the case 10 and is exposed to the outside of the case 10, and the exposed portion is connected to the various external devices described above. The
Hereinafter, a specific structure of the electrode terminal 30 in the present embodiment will be described.

2. Electrode Terminal (1) Constituent Member of Electrode Terminal FIG. 3 is a cross-sectional view schematically showing the structure in the vicinity of the electrode terminal 30 of the sealed battery 100 according to this embodiment. The electrode terminal 30 of the sealed battery 100 according to the present embodiment includes a current collecting member 32, a seal member 39, a bolt 34, an external connection member 36, and an insulating holder 38. Hereinafter, each of these members will be specifically described.

(A) Current collecting member The current collecting member 32 is a long member made of a conductive material. As shown in FIG. 1, one end 32 a of the current collecting member 32 is electrically connected to the electrode body 20 in the case 10, and the other end 32 b penetrates the lid body 14 of the case 10. Exposed outside. Specifically, one end portion 32 a of the current collecting member 32 is formed in a long plate shape, extends along the vertical direction Z of the sealed battery 100, and is a terminal of the electrode body 20 in the case 10. It is connected to the connection unit 20B. On the other hand, the other end portion 32b of the current collecting member 32 is exposed to the outside of the case 10 through each of the seal member 39, the lid body 14, the insulating holder 38, and the external connection member 36, as shown in FIG. ing. The current collecting member 32 fixes the above-described members to the lid 14 of the case 10 by caulking the other end 32b formed in a cylindrical shape as shown in FIG. doing. Examples of the conductive material used for the current collecting member 32 include aluminum and copper.

(B) Seal Member As shown in FIG. 3, in the sealed battery according to the present embodiment, the current collector 32 and the lid are used to prevent the current collector 32 and the lid 14 from being energized. A seal member 39 that is a plate-like insulating member is disposed between the body 14 and the body 14. The sealing member 39 is formed with a current collecting member insertion hole 39a through which the end portion 32b of the current collecting member 32 is inserted, and a sealing portion 39b protruding upward is provided around the current collecting member insertion hole 39a. It has been. The sealing portion 39b is inserted into the current collecting member insertion hole 14a of the lid body 14, and prevents the lid body 14 and the current collecting member 32 from coming into contact with each other inside the current collecting member insertion hole 14a. The current collecting member insertion hole 14a of the lid 14 is sealed to seal the case 10. In addition, as a material used for the sealing member 39, insulating resins, such as a polyamide resin, a polyacetal resin, a polyimide resin, are mentioned, for example.

(C) Bolt The bolt 34 is a conductive member provided with a columnar connection portion 34a standing outside the case 10 along the vertical direction Z of the sealed battery, and is made of the same material as the current collecting member 32 described above. It is preferable to be configured. A screw groove (not shown) is formed on the outer peripheral surface of the columnar connecting portion 34a. For example, after the connection part 34a of the bolt 34 is passed through a plate-like bus bar (not shown), the sealed battery and the external device are electrically connected by tightening a nut into the connection part 34a.
On the other hand, with this bolt 34, in order to prevent the bolt 34 from rotating when it is connected to the external device described above, as shown in FIG. 2 and FIG. A certain fitting portion 34b is formed. As will be described in detail later, the fitting portion 34b of the bolt 34 is designed so as to correspond in shape and size to the bolt housing portion 38a of the insulating holder 38, and the fitting portion 34b of the bolt 34 is replaced with the insulating holder 38. The rotation of the bolt 34 is restricted by fitting in the bolt storage portion 38a. The specific shape and dimensions of the fitting portion 34b can be appropriately changed as necessary.

(D) External Connection Member The external connection member 36 is a plate-like conductive member that electrically connects the current collecting member 32 and the bolt 34 described above. Specifically, the external connection member 36 extends along the width direction X of the sealed battery. As shown in FIG. 2, a current collecting member insertion hole 36b through which the current collecting member 32 is inserted is formed at one end of the external connection member 36, and a bolt 34 is inserted at the other end. A bolt insertion hole 36a is provided. Further, the external connection member 36 in the present embodiment is bent so as to correspond to the shape of the upper surface of an insulating holder 38 to be described later. For the external connection member 36, the same kind of conductive material as that of the current collecting member 32 can be used.

(E) Insulating Holder The insulating holder 38 is an insulating member provided to insulate the external connection member 36 and the lid body 14. As the material of the insulating holder 38, an insulating material of the same type as the sealing member 39 (for example, polyamide resin, polyacetal resin, polyimide resin, etc.) can be preferably used.
The insulating holder 38 is disposed between the external connection member 36 and the lid body 14, and each conductive member (the current collecting member 32, the bolt 34, and the external connection member 36) constituting the electrode terminal 30 is a case. It prevents energizing the 10 lids 14. Specifically, the insulating holder 38 extends along the width direction X of the sealed battery 100 similarly to the external connection member 36 described above, and is disposed between the external connection member 36 and the lid body 14. . A current collecting member insertion hole 38c through which the current collecting member 32 is inserted is formed at one end of the insulating holder 38, and a concave bolt that accommodates the fitting portion 34b of the bolt 34 is formed at the other end. A storage portion 38a is provided.

The insulating holder 38 in this embodiment is provided with a structure for restricting the rotation of the bolt 34. Specifically, the bolt housing portion 38a of the insulating holder 38 is formed in a shape and size corresponding to the fitting portion 34b of the bolt 34, and the fitting portion 34b of the bolt 34 is spaced from the bolt housing portion 38a. The rotation of the bolts 34 is restricted by fitting them together.
In the present embodiment, the bolt storage portion 38a is formed in a rectangular recess, and the interval between the side walls 38b of the bolt storage portion 38a (that is, the length of one side of the bottom surface of the bolt storage portion 38a) is rectangular. It is set to be slightly larger than one side of the fitting portion 34b of the bolt 34 which is a portion.

  In the sealed battery insulation holder 38 according to the present embodiment, a concave dimension absorbing portion 38d is formed on the bottom surface of the bolt housing portion 38a in order to suppress the thermal expansion of the bolt housing portion 38a. The structure related to the dimension absorbing portion 38d will be described in detail later.

(2) Construction of Electrode Terminal The electrode terminal 30 of the sealed battery 100 according to the present embodiment is constructed by assembling each member described above to the lid body 14 of the case 10.

  In constructing the electrode terminal 30, first, the insulating holder 38 and the seal member 39 are attached to the lid body 14. Specifically, the insulating holder 38 is disposed on the upper surface of the lid body 14 and the seal member 39 is disposed on the lower surface so that the current collecting member insertion holes 14a, 38c, 39a of the respective members communicate with each other. Then, the bottom surface of the insulating holder 38 and the sealing portion 39b of the sealing member 39 are pressure-bonded by sandwiching and pressing the insulating holder 38 and the sealing member 39. Thereby, the insulating holder 38 and the seal member 39 are attached to the lid body 14, and the current collecting member insertion hole 14 a of the lid body 14 is covered with the insulating member.

  Next, the bolt 34 and the external connection member 36 are disposed on the insulating holder 38. Specifically, after the bolt 34 is disposed on the upper surface of the insulating holder 38 so that the bolt storage portion 38a fits into the fitting portion 34b, the connection portion 34a of the bolt 34 is inserted into the bolt insertion hole 36a of the external connection member 36. The external connection member 36 is disposed on the upper surface of the insulating holder 38 by being inserted.

  Then, the other end portion 32b of the current collecting member 32 is inserted into the current collecting member insertion holes 39a, 14a, 38c, 36b formed in the seal member 39, the lid body 14, the insulating holder 38, and the external connection member 36, respectively. After the insertion, the other end 32b of the current collecting member 32 is caulked to fix each member described above to the lid 14 of the case 10. Thereby, an electrode terminal 30 having a structure as shown in FIG. 3 is constructed.

(3) Dimension Absorbing Part As described above, in the sealed battery 100 according to this embodiment, the dimension absorbing part 38d is provided on the bottom surface of the bolt accommodating part 38a in order to suppress the thermal expansion of the bolt accommodating part 38a of the insulating holder 38. Is formed. Hereinafter, the dimension absorbing portion 38d will be described.
FIG. 4 is a diagram schematically showing an insulating holder used for the electrode terminal of the sealed battery according to the present embodiment. FIG. 4 (a) is a perspective view, FIG. 4 (b) is a plan view, and FIG. ) Is a cross-sectional view taken along the line CC in FIG. FIG. 5 is a plan view schematically showing the vicinity of the bolt housing portion of the insulating holder in the present embodiment.

As shown in FIG. 4, in the sealed battery 100 according to the present embodiment, two concave dimension absorbing portions 38 d are formed near the center of the bottom surface of the bolt housing portion 38 a of the insulating holder 38. As shown in FIG. 4B, the dimension absorbing portions 38d are formed side by side along the longitudinal direction of the insulating holder 38 (in other words, the width direction X of the sealed battery shown in FIG. 3).
In the insulating holder 38 in which the dimension absorbing portion 38d is formed, a residual stress A directed to the dimension absorbing portion 38d is generated on the bottom surface of the bolt housing portion 38a as shown in FIG. For this reason, even if the insulation holder 38 is heated by the frictional heat generated when the bolt 34 and the external device are connected, and the thermal stress B that tends to expand is generated on the bottom surface of the bolt housing portion 38a, the residual stress A described above. Since the thermal stress B can be reduced, expansion of the bottom surface of the bolt housing portion 38a can be suppressed.

  As described above, according to this embodiment, the thermal expansion of the bolt housing part 38a of the insulating holder 38 can be suppressed, and the interval between the side walls 38b of the bolt housing part 38a can be prevented from widening. For this reason, the fitting part 34b of the bolt 34 and the bolt storage part 38a of the insulating holder 38 can be appropriately fitted to suitably restrict the rotation of the bolt 34, and the bolt 34 can be connected to an external device. It is possible to appropriately prevent the occurrence of connection failure due to the rotation.

  In addition, it is preferable that the dimension absorption part 38d adjusts a shape and a dimension suitably from a viewpoint that the suitable residual stress A is produced in the bottom face of the bolt accommodating part 38a. For example, in the present embodiment, the dimension absorbing portion 38d having a circular shape in plan view is formed, and the diameter of the circular dimension absorbing portion 38d is such that the bolt housing portion 38a has an appropriate residual stress A. It is preferable to adjust appropriately in consideration of the dimensional relationship. For example, when the length of one side of the bolt housing portion 38a is 6 mm to 10 mm, the diameter of the dimension absorbing portion 38d is set within the range of 0.5 mm to 2.0 mm (more preferably 1 mm to 1.5 mm). It is preferable.

  Also, the depth d1 of the dimension absorbing portion 38d shown in FIG. 4C is preferably adjusted as appropriate in order to generate an appropriate residual stress A. For example, if the dimension absorbing portion 38d is deepened, the residual stress A (see FIG. 5) generated on the bottom surface of the bolt housing portion 38a increases. However, if it is too deep, the durability of the insulating holder 38 may be reduced. In addition, if the dimension absorbing portion 38d is formed so as to penetrate the insulating holder 38, there is a possibility that the bolt 34 and the lid body 14 may be energized when conductive foreign matter such as metal powder enters the dimension absorbing portion 38d. The depth d1 of the dimension absorbing portion 38d is preferably adjusted so as not to penetrate the insulating holder 38. Specifically, when the thickness of the insulating holder 38 in the bolt housing portion 38a is about 1.5 mm to 3 mm, the depth d1 of the dimension absorbing portion 38d is set within a range of 0.5 mm to 2.5 mm. Is preferred.

  In general, the insulating holder 38 is manufactured by heating and molding an insulating material and then cooling to room temperature. However, in the dimension absorbing portion 38d in the present embodiment, the insulating holder 38 molded at a high temperature is cooled. It is preferable that it is formed on the bottom surface of the bolt housing part 38a before. Thereby, during cooling, the bottom surface of the bolt housing portion 38a can be greatly shrunk toward the dimension absorbing portion 38d, and the residual stress A toward the dimension absorbing portion 38d can be suitably generated on the bottom surface of the bolt housing portion 38a. As a means for forming the dimension absorbing portion 38d in the insulating holder 38 before cooling in this way, for example, the insulating material is heat-molded using a molding die having a convex portion corresponding to the dimension absorbing portion 38d. Means are mentioned.

3. Other Embodiments Although one embodiment of the sealed battery disclosed herein has been described, the present invention is not limited to the above-described embodiment, and various structures can be changed.

  For example, in the above-described embodiment, the shape of each of the fitting portion 34b of the bolt 34 and the bolt storage portion 38a of the insulating holder 38 is rectangular, but the shape of the fitting portion 34b and the bolt storage portion 38a is as follows. Any prismatic shape that can regulate the rotation of the bolt 34 may be used, and it may be formed in a prismatic shape such as a triangular prism or a pentagonal prism.

  In the above-described embodiment, the two dimension absorbing portions 38d are formed on the bottom surface of the bolt storage portion 38a. However, the number of the dimension absorbing portions 38d is not particularly limited. For example, as shown in FIG. The number of dimension absorbing portions 38d may be only one. However, from the viewpoint of generating an appropriate residual stress on the bottom surface of the bolt housing portion 38a, it is preferable to form a plurality of dimension absorbing portions 38d as in the above-described embodiment. In the case where only one circular dimension absorbing portion 38d is provided as shown in FIG. 6, the diameter of the dimension absorbing portion 38d may be set within a range of 2 mm to 5 mm.

  In any of the above-described embodiments, the dimension absorbing portion 38d having a circular shape in plan view is formed. However, the shape of the dimension absorbing portion 38d is not limited to a circle. The shape of the dimension absorbing portion 38d in plan view may be, for example, an ellipse as shown in FIG. 7 or a rectangle as shown in FIG. Even in the case of these shapes, appropriate residual stress can be generated on the bottom surface of the bolt housing portion 38a to suppress thermal expansion of the bottom surface. Moreover, as shown in FIG. 9, even when the rectangular dimension absorption part 38d is formed in a plan view, only one dimension absorption part 38d may be formed.

Moreover, it is preferable that the dimension absorption part 38d is formed in the center part vicinity of the bottom face of the volt | bolt accommodating part 38a irrespective of any shape shown in above-mentioned FIGS. Thereby, the residual stress toward the dimension absorbing portion 38d can be uniformly generated on the bottom surface of the bolt housing portion 38a, and the thermal expansion of the bolt housing portion 38a can be appropriately suppressed.
“The vicinity of the central portion of the bottom surface of the bolt housing portion” refers to a position where the direction of the residual stress A is from the outside to the inside of the bottom surface of the bolt housing portion 38a. For example, in the case of providing a substantially square-shaped bolt storage portion 38a having a side length of 6 mm to 10 mm, a region within a radius of 5 mm from the center of the bolt storage portion 38a is set near the center portion, and the dimension absorbing portion is provided in the region. 38d may be formed.

[Test example]
Test examples relating to the present invention will be described below, but the following description is not intended to limit the present invention.

1. Each test example (1) Test example 1
In Test Example 1, as shown in FIG. 4, a substantially square bolt housing portion 38a is formed in plan view, and two circular dimension absorbing portions 38d are formed on the bottom surface of the bolt housing portion 38a. An insulating holder 38 was produced. Specifically, an insulating resin (polyamide resin) is filled in a mold in which irregularities corresponding to the structure shown in FIG. 4 are formed, and then cooled to room temperature (25 ° C.) to form an insulating holder 38. did.

(2) Test example 2
In Test Example 2, an insulating holder was manufactured under the same conditions as Test Example 1 except that the dimension absorbing part was not formed on the bottom surface of the bolt housing part.

2. Evaluation test The insulating holder produced in each test example was housed in a thermostatic bath and held at 60 ° C for 60 minutes, and then the length of one side of the bolt housing portion was measured. The measurement results are shown in FIG. FIG. 10 shows the length of one side of the bolt housing part at 60 ° C. when the length of one side of the bolt housing part at room temperature (25 ° C.) is 100%.

3. Evaluation Results As shown in FIG. 10, in the insulating holder of Test Example 2, the bolt storage portion expanded when heated to 60 ° C. and the length of one side increased by 3%. In the holder, the expansion of the bolt storage portion was suppressed to 1%. From this, it was confirmed that the expansion by the heat | fever of the bolt accommodating part of an insulation holder can be suppressed by forming a dimension absorption part in the bottom face of a bolt accommodating part like Test example 1. FIG.

  As mentioned above, although the specific example of this invention was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

DESCRIPTION OF SYMBOLS 10 Case 12 Case main body 14 Cover body 14a Current collection member insertion hole of a cover body 20 Electrode body (winding electrode body)
20A Winding core portion 20B Terminal connecting portion 30 Electrode terminal 32 Current collecting member 32a, 32b End of positive current collecting portion 34 Bolt 34a Connecting portion 34b Fitting portion 36 External connecting member 36a Bolt insertion hole 36b Current collecting of external connecting member Member insertion hole 38 Insulating holder 38a Bolt storage part 38b Side wall of bolt storage part 38c Current collection member insertion hole 38d of insulation holder Dimensional absorption part 39 Seal member 39a Current collection member insertion hole 39b of seal member Sealing part 100 Sealed battery A Residual stress B Thermal stress d1 Dimension absorption part depth X Width direction Z Longitudinal direction

Claims (7)

It is configured by accommodating an electrode body in a case, and is a sealed battery in which an electrode terminal connected to an external device is provided in the case,
The electrode terminal is
A current collecting member having one end electrically connected to the electrode body in the case and the other end exposed to the outside of the case;
A bolt in which a columnar connecting portion connected to the external device is formed at one end, and a fitting portion that is a square convex portion is formed at the other end,
A plate-like external connection member for electrically connecting the current collecting member and the bolt;
An insulating member disposed between the external connection member and the case, wherein an insulating holder is formed with a bolt housing portion that is a square recess that fits with the fitting portion of the bolt. And
Here, a sealed battery in which a concave dimension absorbing portion is formed on the bottom surface of the bolt housing portion.   The sealed battery according to claim 1, wherein the dimension absorbing portion is formed in the vicinity of a central portion of a bottom surface of the bolt housing portion.   The sealed battery according to claim 1, wherein two or more dimension absorbing portions are formed on a bottom surface of the bolt housing portion.   The sealed battery according to any one of claims 1 to 3, wherein a shape of the dimension absorbing portion in plan view is any one of a circle, an ellipse, and a rectangle.   The sealed battery according to any one of claims 1 to 4, wherein the dimension absorption part has a circular shape in plan view, and the diameter of the planar dimension absorption part is 1 mm to 5 mm.   The sealed battery according to any one of claims 1 to 5, wherein a depth of the dimension absorbing portion is 0.5 mm to 2.5 mm. An electrode terminal provided in the case of the sealed battery in which the electrode body is accommodated in the case and connected to an external device,
A current collecting member having one end electrically connected to the electrode body in the case and the other end exposed to the outside of the case;
A bolt in which a columnar connecting portion connected to the external device is formed at one end, and a fitting portion that is a square convex portion is formed at the other end,
A plate-like external connection member for electrically connecting the current collecting member and the bolt;
An insulating member disposed between the external connection member and the case, wherein an insulating holder is formed with a bolt housing portion that is a square recess that fits with the fitting portion of the bolt. And
Here, a concave dimension absorbing portion is formed on the bottom surface of the bolt housing portion, and a residual stress toward the dimension absorbing portion is generated on the bottom surface of the bolt housing portion.

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