JP6783686B2 - Sealed battery and electrode terminals - Google Patents

Description

The present invention relates to a sealed battery and electrode terminals used in the sealed battery.

Secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries are becoming increasingly important as power sources for vehicles and personal computers and mobile terminals. Such a secondary battery is constructed as, for example, a sealed battery in which an electrode body is sealed in a case together with an electrolyte substance.
The case of such a sealed battery is provided with electrode terminals that are electrically connected to other external devices such as batteries and motors. For example, by arranging two or more sealed batteries adjacent to each other and connecting the electrode terminals of the batteries to each other via a bus bar, it is possible to construct an assembled battery composed of a plurality of batteries. Patent Document 1 describes a technique relating to a sealed battery provided with such an electrode terminal.

FIG. 1 shows an example of a sealed battery provided with such an electrode terminal. The sealed battery 100 shown in FIG. 1 includes a flat square case 10, and the electrode body 20 is housed inside the case 10. The case 10 includes a flat square case body 12 having an open upper surface and a lid 14 that closes the opening on the upper surface of the case body 12, and is positive to the lid 14 forming the upper surface of the case 10. The electrode terminal 30 of the negative electrode is provided.
Each electrode terminal 30 includes a current collecting member 32, a bolt 34, and an external connecting member 36. One end 32a of the current collecting member 32 is connected to the electrode body 20 in the case 10, and the other end 32b is exposed to the outside of the case 10. Further, the bolt 34 includes a columnar connecting portion 34a that is electrically connected to the above-mentioned external device. Then, in the electrode terminal 30, the above-mentioned current collecting member 32 and the bolt 34 are electrically connected by a plate-shaped external connecting member 36. Further, in the electrode terminal 30, an insulating holder 38 is arranged between the external connecting member 36 and the lid 14 in order to prevent each of the above members from energizing the case 10 (lid 14). There is.

At the electrode terminal 30, the connection portion 34a of the bolt 34 and the external device are connected by tightening the nut or the like, but if the bolt 34 rotates at this time, a connection failure may occur between the bolt 34 and the external device. There is.
In order to prevent a connection failure due to the rotation of such bolts, the above-mentioned insulating holder 38 is provided with a bolt storage portion that regulates the rotation of the bolts 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 accommodating portion 38a, which is a rectangular recess having the above, is provided. Then, by fitting the fitting portion 34b of the bolt 34 and the bolt accommodating portion 38a of the insulating holder 38, the rotation of the bolt 34 is restricted, and the bolt 34 is prevented from rotating when connected to an external device. Will be done.

Patent No. 4985840

However, in the sealed battery 100 having the above structure, an extremely large load is applied to the bolt storage portion 38a of the insulating holder 38 due to nut tightening when connecting to an external device, and the bolt storage portion 38a may be damaged. It was. If the bolt housing portion 38a is damaged in this way, it becomes difficult to properly insulate each conductive member constituting the electrode terminal 30 from the case 10 (lid body 14), or an external device due to improper tightening. There is a risk that the resistance of the electrical connection with will increase.
For this reason, the manufacturing process of the sealed battery is provided with an inspection process for inspecting the presence or absence of damage to the bolt storage portion, but it is difficult to detect damage to the bolt storage portion in such an inspection process, and such bolts. It takes a lot of labor and time to sufficiently inspect the storage part for damage to all the batteries after manufacturing, which has been a factor of lowering the manufacturing efficiency.

The present invention has been made in view of this point, and a main object thereof is a sealed battery having a structure capable of easily inspecting damage to an insulating holder due to a load when connected to an external device. The purpose is to provide.

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

The sealed battery disclosed here is configured by accommodating an electrode body in a case, and an electrode terminal connected to an external device is provided in the case.
The electrode terminals in such a sealed battery have a current collecting member whose one end is electrically connected to the electrode body inside the case and whose other end is exposed to the outside of the case, and one end. A bolt having a columnar connecting portion connected to an external device and a fitting portion having a square convex portion formed at the other end, and a current collecting member and a bolt are electrically connected to each other. A plate-shaped external connecting member connected to the above, and an insulating member arranged between the external connecting member and the case, formed by a bolt storage portion which is a square concave portion that fits with the fitting portion of the bolt. It is equipped with an insulating holder.
Then, in the sealed battery disclosed here, a concave strength reducing portion is formed at at least one of a plurality of side walls forming the bolt accommodating portion.

The present inventor has conducted various studies in order to solve the above-mentioned problems, and controls the damaged portion in the insulating holder, that is, a large load is applied to the bolt storage portion of the insulating holder in connection with an external device such as nut tightening. It was thought that it would be easier to detect damage to the bolt storage part in the inspection process if damage could occur from a specific location in the bolt storage part when it was hung.

Therefore, the present inventor has further studied and came up with the idea of forming a concave strength-reducing portion at at least one of the plurality of side walls forming the bolt accommodating portion, as in the sealed battery disclosed here. It was. By forming such a strength reducing portion, when a large load is applied to the bolt accommodating portion, the bolt accommodating portion can be damaged starting from the strength reducing portion. For this reason, it becomes possible to easily inspect whether or not the bolt storage portion is damaged by simply checking the periphery of the strength-reduced portion in the inspection process, which reduces labor and time in the inspection process. be able to.

Further, in a preferred embodiment of the sealed battery disclosed herein, at least one strength reducing portion is formed on each side wall forming the bolt accommodating portion.
As described above, if the strength reducing portion is provided at at least one of the plurality of side walls forming the bolt accommodating portion, the bolt accommodating portion can be damaged starting from the strength reducing portion. Is more preferably formed on each side wall forming the bolt accommodating portion. As a result, it is possible to appropriately prevent a portion other than the strength-reduced portion from becoming a starting point of damage.

In another preferred embodiment of the sealed battery disclosed herein, a strength reducing portion is formed near the central portion in the longitudinal direction of the side wall of the bolt accommodating portion.
It is preferable that the above-mentioned strength lowering portion is formed at a portion that is easily deformed when a large load is applied. As a result, it is possible to more appropriately prevent a portion other than the strength-reduced portion from becoming a starting point of damage. As an example of such a easily deformable portion, the vicinity of the central portion in the longitudinal direction of the side wall can be mentioned.

Further, in another preferred embodiment of the sealed battery disclosed herein, a plate-shaped external connecting member is bent in a stepped shape along the upper surface of the insulating holder, and the stepped portion of the external connecting member and the insulating holder A strength reduction portion is formed in the vicinity of the contact position.
When tightening a nut on a bolt for connection with an external device, a large load may be applied to the external connection member arranged on the upper surface of the insulating holder. In such a case, the stepped portion of the external connecting member may be bent along the tightening direction of the nut, and the stepped portion of the bent external connecting member may press the insulating holder. Considering the load applied to the insulating holder due to such deformation of the external connecting member, it is preferable to provide a strength reducing portion near the position where the step portion of the external connecting member and the insulating holder come into contact with each other. As a result, it is possible to appropriately prevent damage from occurring from a location other than the strength-reduced portion.

The present invention also provides an electrode terminal used in the above-mentioned sealed battery as one aspect for solving the above-mentioned problem.
Such an electrode terminal has a current collector whose one end is electrically connected to an electrode body inside the case and whose other end is exposed to the outside of the case, and an external device at one end. A plate that electrically connects a current collector member and a bolt with a bolt having a columnar connection portion connected to the bolt and a fitting portion having a square convex portion formed at the other end portion. Insulation that is an insulating member arranged between the external connecting member and the case, and has a bolt accommodating portion that is a square recess that fits with the fitting portion of the bolt. It has a holder.
Then, in the electrode terminal disclosed here, a concave strength reducing portion is formed at at least one position on the side wall of the bolt accommodating portion.

With the electrode terminal having such a configuration, when a large load is applied to the side wall of the bolt storage portion when connecting to an external device, the bolt storage portion can be damaged starting from the strength reduction portion. It is possible to determine whether or not the insulating holder is damaged only by checking the periphery of the strength-reduced portion. Therefore, when manufacturing a closed-type battery, labor and time in the inspection process can be reduced by using the above-mentioned electrode terminals.

It is a perspective view which shows typically the closed type battery. It is an exploded perspective view of the electrode terminal of the sealed battery shown in FIG. It is sectional drawing which shows typically the structure near the electrode terminal of the closed type 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 closed type battery which concerns on one Embodiment of this invention, FIG. 4A is a perspective view, FIG. 4B is a plan view, FIG. 4C. ) Is a sectional view taken along line CC in FIG. 4 (b). It is a top view which shows typically the vicinity of the bolt accommodating part of the insulation holder in another embodiment of this invention. It is a top view which shows typically the vicinity of the bolt accommodating part of the insulation holder in another embodiment of this invention. It is a perspective view explaining the deformation of an external connection member. It is a top view which shows typically the vicinity of the bolt accommodating part of the insulation holder in another embodiment of this invention.

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

Further, in the following drawings, members / parts having the same action are described with the same reference numerals. The dimensional relationships (length, width, thickness, etc.) in each figure do not reflect the actual dimensional relationships. In addition, matters other than those specifically mentioned in the present specification and necessary for carrying out the present invention (for example, general matters relating to the construction of a lithium ion secondary battery such as the composition and manufacturing method of an electrode body and an electrolyte substance). Technology, etc.) can be grasped as a design item of a person skilled in the art based on the prior art in the field.

1. 1. Overall configuration The basic structure of the closed-type battery according to the present embodiment is the same as that of the conventional closed-type battery. Specifically, as shown in FIG. 1, the sealed battery 100 according to the present embodiment is configured by accommodating the electrode body 20 inside a flat square case 10. The case 10 of the sealed battery 100 is composed of a flat square case body 12 having an open upper surface and a plate-shaped lid 14 that closes the opening on the upper surface of the case body 12. The case 10 is preferably composed mainly of a lightweight metal material having good thermal conductivity, and examples of the metal material include aluminum.

The electrode body 20 housed inside the case 10 includes a positive and negative electrode in which a mixture layer containing an electrode active material capable of occluding and releasing lithium ions is applied to the surface of a foil-shaped current collector.
In this embodiment, a wound electrode body is used as the electrode body 20. Although not shown, the wound electrode body 20 is formed on the surface of a long sheet-shaped positive electrode having a positive electrode mixture layer applied to the surface of the foil-shaped positive electrode current collector and the surface of the foil-shaped negative electrode current collector. It is provided with a long sheet-shaped negative electrode to which a negative electrode mixture layer is provided, and these positive and negative electrodes are laminated via a separator and formed by winding the laminated body. A winding core portion 20A facing the positive and negative electrode mixture layers is formed in the central portion of the winding electrode body 20 in the width direction X, while the winding core portions 20A are formed at both side edges in the width direction X. A terminal connection portion 20B is formed in which a current collector to which a material layer is not provided is wound.
In the sealed battery 100 according to the present embodiment, the materials of the members (for example, the positive electrode, the negative electrode, the separator, etc.) constituting the electrode body 20 are the same as those used in the conventional general lithium ion secondary battery. Since the above can be used without limitation and does not characterize the present invention, detailed description thereof will be omitted.

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

In the sealed battery 100 according to the present embodiment, the lid 14 forming the upper surface of the case 10 is provided with an electrode terminal 30 that is electrically connected to an external device such as another battery or a motor. The electrode terminal 30 is electrically connected to the electrode body 20 inside the case 10 and is exposed to the outside of the case 10 so that it can be connected to an external device.
Hereinafter, the specific structure of the electrode terminal 30 in this embodiment will be described.

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

(A) Current collector member The current collector member 32 is a long member made of a conductive material. As shown in FIG. 1, one end 32a of the current collecting member 32 is electrically connected to the electrode body 20 in the case 10, and the other end 32b penetrates the lid 14 of the case 10. It is exposed to the outside. Specifically, one end 32a 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, as shown in FIG. 3, the other end portion 32b of the current collecting member 32 penetrates each of the sealing member 39, the lid 14, the insulating holder 38, and the external connecting member 36 and is exposed to the outside of the case 10. ing. Then, the current collecting member 32 fixes each of the above-mentioned members to the lid 14 of the case 10 by crimping the other end portion 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, in order to prevent the current collector 32 and the lid 14 from being energized, the current collector 32 and the lid A seal member 39, which is a plate-shaped insulating member, is arranged between the body 14 and the body 14. The seal member 39 is formed with a current collector insertion hole 39a through which the end portion 32b of the current collector member 32 is inserted, and a sealing portion 39b projecting upward is provided around the current collector member insertion hole 39a. Has been done. The sealing portion 39b is inserted into the current collecting member insertion hole 14a of the lid body 14 to prevent 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 case 10 is sealed by sealing the current collecting member insertion hole 14a of the lid body 14. Examples of the material used for the sealing member 39 include insulating resins such as polyamide resin, polyacetal resin, and polyimide resin.

(C) Bolt The bolt 34 is a conductive member provided with a columnar connecting portion 34a that is erected 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 preferably configured. A screw groove (not shown) is formed on the outer peripheral surface of the columnar connecting portion 34a. For example, the sealed battery and the external device are electrically connected by penetrating the connecting portion 34a of the bolt 34 through a plate-shaped bus bar (not shown) and then tightening the nut to the connecting portion 34a.
On the other hand, in this bolt 34, as shown in FIGS. 2 and 3, in order to prevent the bolt 34 from rotating when connected to the external device described above, a rectangular convex portion is formed on the other end. A fitting portion 34b is formed. As will be described in detail later, the fitting portion 34b of the bolt 34 is designed so that the shape and dimensions correspond to the bolt storage portion 38a of the insulating holder 38, and the fitting portion 34b of the bolt 34 is the insulating holder 38. The rotation of the bolt 34 is restricted by fitting the bolt into the bolt storage portion 38a. The specific shape and dimensions of the fitting portion 34b can be appropriately changed as needed.

(D) External connecting member The external connecting member 36 is a plate-shaped conductive member that electrically connects the current collecting member 32 and the bolt 34 described above. Specifically, the external connecting member 36 extends along the width direction X of the sealed battery. Then, 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 connecting member 36, and a bolt 34 is inserted at the other end. A bolt insertion hole 36a for allowing the bolt to be inserted is provided. Further, the external connecting member 36 in the present embodiment is bent so as to correspond to the shape of the upper surface of the insulating holder 38 described later, and a step portion 36c is formed. As for the external connecting member 36, the same kind of conductive material as the above-mentioned current collecting member 32 can be used.

(E) Insulation Holder The insulation holder 38 is an insulation member provided to insulate the external connection member 36 and the lid 14. As the material of the insulating holder 38, an insulating material of the same type as the sealing member 39 described above (for example, polyamide resin, polyacetal resin, polyimide resin, etc.) can be preferably used.
The insulating holder 38 is arranged between the external connecting member 36 and the lid 14, and each conductive member (current collecting member 32, bolt 34, external connecting member 36) constituting the electrode terminal 30 is a case. It prevents the lid body 14 of 10 from being energized. Specifically, the insulating holder 38 extends along the width direction X of the sealed battery 100 like the external connecting member 36 described above, and is arranged between the external connecting member 36 and the lid 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 for accommodating 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 the present embodiment is provided with a structure for restricting the rotation of the bolt 34. Specifically, the bolt storage portion 38a of the insulating holder 38 is formed in a shape and dimensions corresponding to the fitting portion 34b of the bolt 34, and the fitting portion 34b of the bolt 34 is gapped in the bolt storage portion 38a. The rotation of the bolt 34 is restricted by fitting without.
In the present embodiment, the bolt storage portion 38a is formed in a rectangular concave portion, and the distance 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 a rectangular protrusion. 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 insulated holder 38 of the sealed battery 100 according to the present embodiment, even if the insulation holder 38 is damaged when connected to an external device, the side wall 38b of the bolt storage portion 38a can be easily inspected for the damage. A concave strength-reducing portion is formed in the above, and the structure relating to the strength-reducing portion 38d will be described in detail later.

(2) Construction of Electrode Terminals The electrode terminals 30 of the sealed battery 100 according to the present embodiment are constructed by assembling each of the above-mentioned members to the lid 14 of the case 10.

When constructing such an electrode terminal 30, first, the insulating holder 38 and the sealing member 39 are attached to the lid body 14. Specifically, the insulating holder 38 is arranged on the upper surface of the lid 14 and the seal member 39 is arranged on the lower surface so that the current collecting member insertion holes 14a, 38c, 39a of each member communicate with each other. Then, the bottom surface of the insulating holder 38 and the sealing portion 39b of the sealing member 39 are crimped by sandwiching and pressing the insulating holder 38 and the sealing member 39. As a result, the insulating holder 38 and the sealing member 39 are attached to the lid body 14, and the current collecting member insertion hole 14a of the lid body 14 is covered with the insulating member.

Next, the bolt 34 and the external connecting member 36 are arranged on the insulating holder 38. Specifically, after arranging the bolt 34 on the upper surface of the insulating holder 38 so that the bolt accommodating portion 38a fits into the fitting portion 34b, the connecting portion 34a of the bolt 34 is inserted into the bolt insertion hole 36a of the external connecting member 36. The external connecting member 36 is inserted and arranged on the upper surface of the insulating holder 38.

Then, the other end 32b of the current collector 32 is inserted into the current collector insertion holes 39a, 14a, 38c, 36b formed in each of the seal member 39, the lid 14, the insulating holder 38, and the external connection member 36. After the insertion, each of the above-mentioned members is fixed to the lid 14 of the case 10 by crimping the other end 32b of the current collecting member 32. As a result, the electrode terminal 30 having the structure shown in FIG. 3 is constructed.

(3) Strength reduction portion As described above, in the sealed battery 100 according to the present embodiment, the side wall 38b of the bolt storage portion 38a can be easily inspected for damage to the insulation holder 38 when connected to an external device. A concave strength-reducing portion is formed on the surface. Hereinafter, the strength reducing portion 38d will be described. 4A and 4B are views schematically showing an insulating holder used for an electrode terminal of the sealed battery according to the present embodiment, FIG. 4A is a perspective view, FIG. 4B is a plan view, and FIG. 4C is a plan view. ) Is a sectional view taken along line CC in FIG. 4 (b).

As shown in FIG. 4, in the sealed battery 100 according to the present embodiment, the strength reducing portion 38d is provided on the upper surface of each side wall 38b forming the bolt accommodating portion 38a of the insulating holder 38. As shown in FIG. 4C, the strength-reducing portion 38d is formed in a concave shape on the upper surface of the side wall 38b, and the portion where the strength-reducing portion 38d is formed has an external force more than other portions of the side wall 38b. The strength against is reduced.
Therefore, in the present embodiment, when an excessive load is applied to the side wall 38b of the bolt storage portion 38a when connecting the bolt 34 and the external device, the strength of the reduced strength portion is lower than that of the other portions. The side wall 38b is damaged starting from 38d. Therefore, according to the present embodiment, it is possible to easily inspect whether or not the insulation holder 38 is damaged only by checking the periphery of the strength reduction portion 38d in the inspection step, so that the labor required in the inspection step is required. It is possible to significantly reduce the time and improve the manufacturing efficiency of the sealed battery.

It is preferable that the dimensions of the strength reducing portion 38d are appropriately adjusted from the viewpoint of appropriately causing damage starting from the strength reducing portion 38d.
For example, in the insulating holder 38, sink marks and voids generated in the manufacturing process may be the starting point of breakage. Therefore, even if sink marks or voids occur, the damage starting from the strength reducing portion 38d is appropriate. It is preferable to adjust the size of the strength reducing portion 38d so as to occur in.

Further, it is preferable to appropriately adjust the number and positions of the strength reducing portions 38d from the viewpoint of appropriately causing damage starting from the strength reducing portion 38d.
For example, as shown in FIG. 4B, in the insulating holder 38 in the present embodiment, of the four side walls 38b forming the bolt storage portion 38a, the side wall 38b orthogonal to the longitudinal direction of the insulating holder 38 is thicker. It is formed to be thick and has higher strength than the side wall 38b along the longitudinal direction of the insulating holder 38. Therefore, in the present embodiment, two strength reducing portions 38d are formed on the upper surface of the side wall 38b orthogonal to the longitudinal direction.

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

As described above, the number and position of forming the strength reducing portion 38d are appropriately adjusted in order to appropriately cause damage starting from the strength reducing portion 38d.
For example, as shown in FIG. 5, one strength reducing portion 38d may be formed on each of the four side wall 38b forming the bolt accommodating portion 38a. Further, when one strength reducing portion 38d is formed on the upper surface of the side wall 38b in this way, it is preferable to form the strength reducing portion 38d near the central portion in the longitudinal direction of the side wall 38b. Since the vicinity of the central portion in the longitudinal direction is a portion that is easily deformed when a large load is applied, by forming the strength reduction portion 38d in this portion, damage starting from the strength reduction portion 38d is appropriately generated. Can be made to.

Further, the strength lowering portion 38d may be formed at a position as shown in FIG. FIG. 6 is a plan view schematically showing the vicinity of the bolt storage portion of the insulating holder in another embodiment of the present invention. In FIG. 6, for convenience of explanation, the bolt fitting portion 34b is shown by a dotted line.
As shown in FIG. 6, in an electrode terminal having a general structure, when a bolt rotates when connected to an external device, the corner of the bolt fitting portion 34b is pressed against the side wall 38b of the bolt storage portion 38a. In such a case, the load is concentrated on the portion where the corners of the fitting portion 34b come into contact with each other, and damage is likely to occur starting from this portion. For this reason, it is preferable that the strength lowering portion 38d is formed at a portion where the corners of the fitting portion 34b come into contact with each other when the bolt is rotated.

Further, it is preferable that the strength lowering portion is formed in consideration of not only the fitting portion of the bolt but also the load received from the external connecting member. Specifically, in the sealed battery 100 shown in FIGS. 1 to 3, the plate-shaped external connecting member 36 is bent in a stepped shape along the upper surface of the insulating holder 38 to form a stepped portion 36c. There is. In the sealed battery 100 using the external connection member 36 having such a shape, as shown in FIG. 7, when a large load is applied to the external connection member 36 when the nut is tightened to the connection portion 34a of the bolt 34. The external connecting member 36 may be bent along the tightening direction A of the nut around the step portion 36c.
In such a case, as shown in FIG. 8, the stepped portion 36c of the bent external connecting member may press the insulating holder 38. In such a case, the strength reduction portion 38d is located near the position where the step portion 36c of the external connecting member and the insulation holder 38 come into contact with each other so that the damage starting from the strength reduction portion 38d can be appropriately caused. It is preferably formed in.

Further, in any of the above-described embodiments, a strength reduction portion is formed on the upper surface of the side wall of the bolt storage portion. However, the position where the strength lowering portion is formed is not limited to the upper surface of the side wall, and may be a position other than the upper surface as long as it is the side wall of the bolt storage portion. However, from the viewpoint of facilitating the formation of the strength reducing portion, it is preferable to form the strength reducing portion on the upper surface of the side wall of the bolt storage portion.

In the above-described embodiment, the shapes of the fitting portion 34b of the bolt 34 and the bolt accommodating portion 38a of the insulating holder 38 are rectangular, but the shapes of the fitting portion and the bolt accommodating portion are of the bolt. It may be a square shape that can regulate the rotation, and may be formed in a prismatic shape such as a triangular prism or a pentagonal prism. When the shapes of the fitting portion and the bolt accommodating portion are changed in this way, it is preferable to appropriately adjust the position of forming the strength reducing portion according to the shapes of the fitting portion and the bolt accommodating portion.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples illustrated above.

10 Case 12 Case body 14 Lid body 14a Current collector insertion hole of lid body 20 Electrode body (rolling electrode body)
20A Winding core part 20B Terminal connection part 30 Electrode terminal 32 Current collector 32a, 32b End of positive current collector 34 Bolt 34a Connection 34b Fitting part 36 External connection member 36a Bolt insertion hole 36b Current collection of external connection member Member insertion hole 38 Insulation holder 38a Bolt storage 38b Side wall of bolt storage 38c Current collector insertion hole for insulation holder 38d Strength reduction part 39 Sealing member 39a Current collecting member insertion hole for sealing member 39b Sealing part 100 Sealed battery A Tightening direction of nut X Width direction Z Vertical direction

Claims (5)

A sealed battery in which an electrode body is housed in a case and an electrode terminal connected to an external device is provided in the case.
The electrode terminal is
A current collecting member whose one end is electrically connected to the electrode body in the case and whose other end is exposed to the outside of the case.
A bolt having a columnar connection portion connected to the external device formed at one end and a fitting portion having a rectangular convex portion formed at the other end.
A plate-shaped external connecting member that electrically connects the current collecting member and the bolt,
It is provided with an insulating member arranged between the external connecting member and the case, and having an insulating holder formed with a bolt storage portion which is a square concave portion that fits with the fitting portion of the bolt. And
Here, a sealed battery in which at least one side wall of a plurality of side walls forming the bolt storage portion has a concave strength-reducing portion formed at a specific position excluding the entire region of the side wall . The sealed battery according to claim 1, wherein at least one of the strength reducing portions is formed on each side wall forming the bolt accommodating portion. The sealed battery according to claim 1 or 2, wherein the strength reducing portion is formed in the vicinity of the central portion in the longitudinal direction of the side wall of the bolt accommodating portion. The plate-shaped external connecting member is bent in a stepped shape along the upper surface of the insulating holder, and the strength reducing portion is formed in the vicinity of the position where the stepped portion of the external connecting member and the insulating holder come into contact with each other. The sealed battery according to any one of claims 1 to 3. An electrode terminal provided in the case of a sealed battery in which an electrode body is housed in a case and connected to an external device.
A current collecting member whose one end is electrically connected to the electrode body in the case and whose other end is exposed to the outside of the case.
A bolt having a columnar connection portion connected to the external device formed at one end and a fitting portion having a rectangular convex portion formed at the other end.
A plate-shaped external connecting member that electrically connects the current collecting member and the bolt,
It is provided with an insulating member arranged between the external connecting member and the case, and having an insulating holder formed with a bolt storage portion which is a square concave portion that fits with the fitting portion of the bolt. And
Here, an electrode terminal in which at least one side wall of a plurality of side walls forming the bolt accommodating portion has a concave strength reducing portion formed at a specific portion excluding the entire region of the side wall .

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