Sealing body and insulating airtight member

Abstract

To provide a sealing body capable of ensuring insulation between a battery terminal and a lid body.SOLUTION: A sealing body has an insulating airtight member 30. The insulating airtight member 30 includes a first member 31 which is interposed in a compressed state between a shaft portion 25b of a battery terminal 25 and an inner circumferential surface of an attachment port 14 of a lid body 13 and between the back surface of a flat portion 25a of the battery terminal 25 and the surface of the lid body 13, and a second member 35 that is made of a material having a larger Young's modulus than that of the first member 31 and disposed at a position facing an end face of the first member 31. The second member 35 faces the end face of the first member 31 and has a receiving portion 37 for receiving deformation of the first member 31 at a position facing the surface of the lid body 13. A part of the end portion of the first member 31 is located within the receiving portion 37 of the second member 35, and has an overlapping portion S consisting of a part of the first member 31 and a part of the second member 35 that overlap each other in a vertical direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a sealing body used for a sealed secondary battery and an insulating and airtight member used therefor.

Background Art

[0002] Conventionally, a secondary battery used for an electric vehicle having a motor such as an electric car as a drive source includes an electrode body, a case in which the electrode body is housed, a battery terminal attached to the case and electrically connected to the electrode body, and the like. In this type of secondary battery, the battery terminal is inserted into an attachment port formed in a lid body constituting the case, for example, and is electrically connected to the electrode body inside the case. A resin member is disposed between the battery terminal and the lid body, and the resin member insulates between the battery terminal and the lid body and maintains airtightness between the battery terminal and the attachment port. As such a secondary battery, for example, the battery disclosed in Patent Document 1 is known.

[0003] The battery described in Patent Document 1 includes a housing in which a through-hole penetrating between the outside and the inside is formed, an electrode body housed in the housing, an external connection terminal inserted into the through-hole and electrically connected to the electrode body, a seal member that maintains airtightness between the external connection terminal and the through-hole, an insulating member that insulates between the external connection terminal and the housing, and the like. A recess is formed on the outer surface of the housing outside the outer edge of the external connection terminal. In this battery, the seal member is interposed in a compressed state between the external connection terminal and the inner peripheral surface of the through-hole, the contact portion abuts against the end portion of the seal member, and the insulating member is arranged such that the protruding portion is located in the recess formed in the housing.

[0004] In the above battery, the protruding portion of the insulating member and the recess of the housing are engaged with each other. Thus, according to the above battery, when the external connection terminal is caulked, when the seal member is compressed and bulges along the surface of the housing and the end portion of the seal member is pressed against the contact portion of the insulating member, deformation of the insulating member is suppressed, and generation of a gap between the insulating member and the housing surface is suppressed.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the battery described in Patent Document 1, when the external connection terminal is clamped, when the sealing member is deformed and abuts against the insulating member, the protruding portion is located within the concave portion, so that the insulating member cannot move along the surface of the housing. Therefore, depending on the degree of deformation of the sealing member, an excessive load is applied to the insulating member and the insulating member is damaged, and due to the damage of the insulating member, sufficient insulation between the external connection terminal and the housing cannot be ensured.

[0007] Also, in the battery described in Patent Document 1, the insulation distance (creepage distance) between the external connection terminal and the housing when passing between the end face of the sealing member and the insulating member is only the thickness of the sealing member. Therefore, there is room for improvement in ensuring a sufficient insulation distance and ensuring insulation between the external connection terminal and the housing.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide a sealing body capable of ensuring insulation between a battery terminal and a lid body, and an insulating and airtight member used therefor.

Means for Solving the Problems

[0009] The characteristic configuration of the sealing body according to the present invention for achieving the above object is A sealing body for a sealed secondary battery attached to an opening of a housing, A lid body having an attachment port penetrating through the front and back surfaces, A battery terminal having a flat portion and a shaft portion extending from the back surface of the flat portion, the shaft portion being inserted through the attachment port, An insulating and airtight member that insulates the battery terminal and the lid body and maintains airtightness between the shaft portion of the battery terminal and the mounting port of the lid body is provided. The insulating and airtight member is A first member interposed in a compressed state between the shaft portion of the battery terminal and the inner peripheral surface of the mounting port of the lid body, and between the back surface of the flat portion of the battery terminal and the front surface of the lid body; A second member made of a material having a higher Young's modulus than that of the first member and disposed at a position facing the end surface of the first member; The second member has a receiving portion for receiving the deformation of the first member at a position facing the end surface of the first member and facing the back surface of the flat portion of the battery terminal or the front surface of the lid body. A part of the end of the first member is located in the receiving portion of the second member, and there is an overlapping portion composed of a part of the first member and a part of the second member that overlap in the vertical direction.

[0010] According to the above characteristic configuration, during the caulking process for assembling the battery terminal and the insulating and airtight member to the lid body, the first member made of a material having a relatively low Young's modulus is deformed by the compression during caulking, and the deformation of the first member is received by the receiving portion of the second member made of a material having a higher Young's modulus than that of the first member. Therefore, the load on the second member caused by the deformation of the first member is alleviated, and the deformation of the second member is suppressed. Thus, the sealing body is less likely to be damaged during manufacturing. In addition, by having an overlapping portion where a part of the first member and a part of the second member overlap in the vertical direction, no gap is generated between the first member and the second member, and the insulation distance (creepage distance) between the battery terminal and the lid body when passing between the first member and the second member is longer than when no overlapping portion is formed. Therefore, according to the above characteristic configuration, the occurrence of insulation failure due to damage to the insulating and airtight member or insufficient insulation distance between the battery terminal and the lid body can be suppressed, and insulation between the battery terminal and the lid body can be ensured.

[0011] A further characteristic configuration of the sealing body according to the present invention is The overlapping portion is located between the back surface of the flat portion of the battery terminal and the front surface of the lid body, the thickness of the portion sandwiched between the back surface of the flat portion in the first member and the front surface of the lid body in the compressed state is the same as the thickness of the overlapping portion, and the thickness of the portion sandwiched between the back surface of the flat portion in the second member and the front surface of the lid body is equal to or less than the thickness of the portion sandwiched between the back surface of the flat portion in the first member and the front surface of the lid body and the thickness of the overlapping portion.

[0012] According to the above characteristic configuration, between the back surface of the flat portion of the battery terminal and the front surface of the lid body, since the overlapping portion is sandwiched therebetween, a part of the first member is difficult to come out along the direction parallel to the front surface of the lid body from within the receiving portion. Therefore, the movement of the second member in the direction parallel to the front surface of the lid body is suppressed.

[0013] A further characteristic configuration of the sealing body according to the present invention is that the first member and the second member are engaged with each other in the overlapping portion.

[0014] According to the above characteristic configuration, the movement of the second member in the direction parallel to the front surface of the lid body can be further suppressed.

[0015] A characteristic configuration of the insulating and airtight member according to the present invention for achieving the above object is a lid body having a mounting port penetrating through the front and back surfaces, and a battery terminal having a flat portion and a shaft portion extending from the back surface of the flat portion and inserted into the mounting port, used for a sealing body of a secondary battery, insulating the battery terminal and the lid body, and maintaining the airtightness between the shaft portion of the battery terminal and the mounting port of the lid body, and is an insulating and airtight member, a first member having a cylindrical portion interposed between the shaft portion of the battery terminal and the inner peripheral surface of the mounting port of the lid body, a first plate-like portion extending from the outer peripheral surface of the cylindrical portion and interposed between the back surface of the flat portion of the battery terminal and the front surface of the lid body, and a thin-walled portion extending from the end surface of the first plate-like portion; A second plate-like portion interposed between the back surface of the flat portion of the battery terminal and the surface of the lid body, and a position in the second plate-like portion that faces the end surface of the first plate-like portion and faces the back surface of the flat portion of the battery terminal or the surface of the lid body, and has a receiving portion in which the thin-walled portion of the first plate-like portion is accommodated, and a second member made of a material having a higher Young's modulus than the first member, The second member and the thin-walled portion of the first member accommodated in the receiving portion of the second member form an overlapping portion arranged side by side in a direction parallel to the thickness direction of the first plate-like portion and the second plate-like portion. There is a gap between the thin-walled portion of the first member and the inner surface of the receiving portion. The thickness of the first plate-like portion is equal to or greater than the sum of the thickness of the thin-walled portion and the thickness of the remaining portion of the second plate-like portion from which the receiving portion has been cut out. When compressed along a direction parallel to the thickness direction of the first plate-like portion and the second plate-like portion and sandwiched between the back surface of the flat portion of the battery terminal and the surface of the lid body, the thickness of the first plate-like portion is at a point equal to the sum of the thickness of the thin-walled portion and the thickness of the remaining portion of the second plate-like portion from which the receiving portion has been cut out.

[0016] According to the above characteristic configuration, when the battery terminal and the insulating and airtight member are attached to the lid body by caulking using this insulating and airtight member, the first member made of a material with a relatively low Young's modulus deforms due to the compression during caulking, and the deformation of the first member is received by the receiving portion of the second member made of a material with a higher Young's modulus than the first member. Therefore, the load on the second member caused by the deformation of the first member is alleviated, and the deformation of the second member is suppressed. Thus, by using the insulating and airtight member according to the present invention, a sealed body with reduced damage to the insulating and airtight member can be realized. In addition, since the thin-walled portion of the first member and the second member have an overlapping portion that overlaps in a direction parallel to the thickness direction of the first plate-like portion and the second plate-like portion, no gap is generated between the first member and the second member, and the insulation distance (creepage distance) between the battery terminal and the lid body becomes longer than when no overlapping portion is formed. That is, according to the hermetic insulation member having the above-described characteristic configuration, a sealing body with ensured insulation between the battery terminal and the lid body can be realized.

Advantages of the Invention

[0017] As described above, according to the sealing body and the hermetic insulation member according to the present invention, insulation between the battery terminal and the lid body can be ensured.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0019] Hereinafter, with reference to the drawings, a sealing body and a hermetic insulation member according to an embodiment of the present invention will be described. In the following, an aspect in which the sealing body and the hermetic insulation member are also used as components of a lithium ion secondary battery will be described as an example. Further, hereinafter, for clarity of explanation, each description and each drawing are appropriately simplified.

[0020] 〔Outline of Secondary Battery 1〕 Referring to FIGS. 1 and 2, an overview of the secondary battery 1 provided with the sealing body 12 and the insulating gaskets 30 and 40 according to this embodiment will be described. Note that FIG. 1 is an exploded perspective view of the secondary battery 1 provided with the sealing body 12 and the insulating gaskets 30 and 40. FIG. 2 is a cross-sectional view showing a schematic configuration of the secondary battery 1. In the following description, the direction parallel to the height direction of the secondary battery 1 is defined as the Z-axis direction, the direction parallel to the longitudinal direction of the electrode body 20 is defined as the X-axis direction, and the direction parallel to the thickness direction of the electrode body 20 is defined as the Y-axis direction. The Z-axis direction is parallel to the vertical direction, the X-axis direction and the Y-axis direction are orthogonal to each other, and are parallel to the horizontal direction.

[0021] As shown in FIGS. 1 and 2, the secondary battery 1 includes a battery case 10 composed of a case body 11 and a sealing plate 13, external terminals 25 and 26, and current collecting terminals 27 and 28, terminal assemblies PS and NS attached to the sealing plate 13, insulating gaskets 30 and 40, and an electrode body 20 electrically connected to the current collecting terminals 27 and 28. The secondary battery 1 is a sealed secondary battery in which the electrode body 20, the current collecting terminals 27 and 28, etc. are housed inside the case body 11, the opening of the case body 11 is sealed with the sealing plate 13, and then an electrolytic solution is injected into the case body 11.

[0022] 〔Configuration of the battery case 10〕 As shown in FIGS. 1 and 2, the battery case 10 of this embodiment is composed of a case body 11 having a substantially rectangular parallelepiped shape with an open top and a sealing plate 13 for sealing the opening of the case body 11. In the battery case 10 of this embodiment, both the case body 11 and the sealing plate 13 are made of aluminum, but it is not limited thereto. Various metals and alloys can be used as the materials of the case body 11 and the sealing plate 13.

[0023] Although details will be described later, the sealing plate 13 of this embodiment constitutes a part of the sealing body 12, has a shape corresponding to the shape of the opening of the case body 11, and is configured to be able to seal the opening of the case body 11.

[0024] 〔Configuration of the electrode body 20〕 The electrode body 20 of the present embodiment is formed of a wound body that is wound in a state where a long strip-shaped positive electrode material and a negative electrode material are laminated via a strip-shaped separator and compressed into a flat shape. As shown in FIGS. 1 and 2, the electrode body 20 is substantially rectangular in a thickness direction view (Y-axis direction view), and a positive electrode terminal joint portion 21 where the positive electrode material is collected on a foil is formed on one end side in the longitudinal direction (X-axis direction) in the thickness direction view, and a negative electrode terminal joint portion 22 where the negative electrode material is collected on a foil is formed on the other end side. The electrode body 20 is housed inside the case body 11 in a posture where the thickness direction and the longitudinal direction are parallel to the horizontal direction, and is insulated from the case body 11 by an insulating film or the like as appropriate. Note that the structure of the electrode body 20 is not particularly limited, and various structures used in general sealed secondary batteries can be adopted. Further, in the present embodiment, aluminum is used for the positive electrode material and copper is used for the negative electrode material.

[0025] 〔Configuration of the sealing body 12〕 The sealing body 12 includes a sealing plate 13, a terminal assembly PS, NS including external terminals 25, 26 and current collecting terminals 27, 28, insulating gaskets 30, 40, lower insulating members 45, 46, and the like.

[0026] As shown in FIGS. 1 and 2, the sealing plate 13 is a plate-shaped member that seals the opening of the case body 11, and through holes 14, 15 penetrating the front and back surfaces (upper and lower surfaces) are formed. Specifically, the sealing plate 13 of the present embodiment is composed of a flat plate member that is substantially rectangular in a Z-axis direction view. A through hole 14 through which the shaft portion 25b of the positive electrode external terminal 25 is inserted is formed on one end side in the longitudinal direction (X-axis direction) of the sealing plate 13, and a through hole 15 through which the shaft portion 26b of the negative electrode external terminal 26 is inserted is formed on the other end side. In the present embodiment, the sealing plate 13 corresponds to the "lid body", and the through holes 14, 15 correspond to the "attachment ports".

[0027] As shown in FIGS. 1 and 2, the sealing body 12 of the present embodiment includes, as a configuration on the positive electrode side, a positive electrode terminal assembly PS (positive electrode external terminal 25 and positive electrode current collecting terminal 27) disposed on one end side in the longitudinal direction of the sealing plate 13, a positive electrode insulating gasket 30, and a positive electrode lower insulating member 45. Further, the sealing body 12 includes, as a configuration on the negative electrode side, a negative electrode terminal assembly NS (negative electrode external terminal 26 and negative electrode current collecting terminal 28) disposed on the other end side in the longitudinal direction of the sealing plate 13, a negative electrode insulating gasket 40, and a negative electrode lower insulating member 46. In the present embodiment, the positive electrode external terminal 25 and the negative electrode external terminal 26 correspond to the "battery terminals", and the positive electrode insulating gasket 30 and the negative electrode insulating gasket 40 correspond to the "insulating airtight members".

[0028] In the sealing body 12 of the present embodiment, except that the materials constituting the external terminals 25, 26 and the current collecting terminals 27, 28 are different between the positive electrode side and the negative electrode side, both have the same configuration. Therefore, hereinafter, taking the positive electrode side as an example, the configuration will be described with reference to FIGS. 3 to 6. Note that FIG. 3 is a cross-sectional view showing the III-III portion of FIG. 2, and FIG. 4 is a cross-sectional view showing the IV-IV portion of FIG. 3. Further, FIG. 5 is an exploded perspective view showing the positive electrode insulating gasket 30. FIG. 6 is a view showing the state near the positive electrode before caulking.

[0029] As shown in FIGS. 3 and 4, the positive electrode external terminal 25 has a plate-shaped planar portion 25a having a substantially rectangular shape in plan view, and a shaft portion 25b extending downward from the back surface of the planar portion 25a. A caulking portion 25c is formed at the lower end side of the shaft portion 25b. In the present embodiment, the positive electrode external terminal 25 is made of aluminum, but the material of the positive electrode external terminal 25 is not particularly limited, and various metals and alloys having good conductivity can be used.

[0030] As shown in FIGS. 3 to 5, the positive electrode insulating gasket 30 is a member that insulates the positive electrode external terminal 25 and the sealing plate 13 and maintains the airtightness between the shaft portion 25b of the positive electrode external terminal 25 and the through hole 14 of the sealing plate 13, and is composed of a first member 31 and a second member 35.

[0031] The first member 31 is a member having a cylindrical portion 32, a first plate-like portion 33, and a thin portion 34.

[0032] In the present embodiment, the cylindrical portion 32 is a cylindrical portion interposed between the shaft portion 25b of the positive electrode external terminal 25 and the inner peripheral surface of the through hole 14 of the sealing plate 13. The shaft portion 25b of the positive electrode external terminal 25 is inserted into the cylinder of the cylindrical portion 32. Further, the first plate-like portion 33 is a plate-like portion having a substantially rectangular shape in a top view that extends horizontally from the outer peripheral surface of the cylindrical portion 32, and is interposed between the back surface of the flat portion 25a of the positive electrode external terminal 25 and the surface of the sealing plate 13. The thin portion 34 is a portion that extends along the horizontal direction from the entire circumference of the side surface of the first plate-like portion 33 and is thinner than the first plate-like portion 33. In other words, the thin portion 34 extends from the entire circumference of the end surface of the first plate-like portion 33.

[0033] The second member 35 is a member having a second plate-like portion 36, a receiving portion 37, and a side wall portion 38.

[0034] In the present embodiment, the second plate-like portion 36 is a portion having a substantially rectangular frame shape in a top view. Further, the receiving portion 37 is a notch-like portion formed on the back surface side of the second plate-like portion 36 from the back surface to the inner surface of the frame, and is a portion that receives the deformation of the first member 31 during caulking, as will be described later. The side wall portion 38 is a frame-like portion having a substantially rectangular shape in a plan view that extends upward from the outer edge portion of the surface of the second plate-like portion 36.

[0035] Both the first member 31 and the second member 35 are members made of an insulating material, but the second member 35 is made of a material having a larger Young's modulus than the material constituting the first member 31. In the present embodiment, the first member 31 is made of PFA resin and the second member 35 is made of PP resin, but the present invention is not limited thereto, and the materials of the respective members 31 and 35 may be appropriately selected so that the material constituting the second member 35 has a larger Young's modulus than the material constituting the first member 31.

[0036] As shown in FIGS. 3 to 5, the positive electrode insulating gasket 30 of the present embodiment is a member disposed on the surface side of the sealing plate 13 in a state where the first plate-like portion 33 and the thin portion 34 of the first member 31 are located within the frame of the second member 35, and the thin portion 34 of the first member 31 is accommodated in the receiving portion 37 of the second member 35. That is, the second member 35 is disposed at a position facing the end surface of the first member 31, and the receiving portion 37 faces the end surface of the first member 31 and is formed at a position facing the surface of the sealing plate 13.

[0037] Further, the positive electrode insulating gasket 30 has an overlapping portion S in which the thin portion 34 of the first member 31 and the remaining portion (hereinafter referred to as "protruding portion 39") from which the receiving portion 37 in the second member 35 is cut out are arranged in the vertical direction. That is, the positive electrode insulating gasket 30 has an overlapping portion S composed of a part of the end portion of the first member 31 (that is, the thin portion 34) located within the receiving portion 37 of the second member 35 and a part of the first member 31 and a part of the second member 35 that overlap in the vertical direction.

[0038] The positive electrode current collecting terminal 27 is a terminal for inputting and outputting electric power from the electrode body 20, and is disposed on the back surface side of the sealing plate 13, in other words, inside the case body 11. In the present embodiment, the positive electrode current collecting terminal 27 is made of aluminum, but the material of the positive electrode current collecting terminal 27 is not particularly limited, and various metals and alloys having good conductivity can be used.

[0039] The positive electrode current collecting terminal 27 is a long plate-like member extending along the Z-axis direction. The positive electrode current collecting terminal 27 of the present embodiment has an electrode connection portion 27a joined to the positive electrode terminal joint portion 21 of the electrode body 20 on the lower end side thereof (see FIGS. 1 and 2). Further, the positive electrode current collecting terminal 27 has a plate-like terminal connection portion 27b having front and back surfaces parallel to the horizontal direction on the upper end side thereof, and a through hole 27c for inserting the shaft portion 25b of the positive electrode external terminal 25 is formed through the front and back surfaces of the terminal connection portion 27b.

[0040] The lower insulating member 45 on the positive electrode side is a member made of an insulating material. In this embodiment, it is a member made of PFA resin formed into a plate shape that is substantially rectangular in plan view. The lower insulating member 45 on the positive electrode side of this embodiment has a through hole 45a formed through the front and back surfaces at the central portion in plan view for inserting the shaft portion 25b of the positive electrode external terminal 25.

[0041] In this embodiment, the caulking portion 25c of the positive electrode external terminal 25 is caulked, and the positive electrode external terminal 25, the positive electrode current collecting terminal 27, the positive electrode insulating gasket 30, and the lower insulating member 45 on the positive electrode side are attached to the sealing plate 13.

[0042] Specifically, as shown in FIG. 6, the lower insulating member 45 on the positive electrode side is arranged so that its surface abuts against the back surface on one end side in the longitudinal direction of the sealing plate 13, and the positive electrode current collecting terminal 27 is arranged below the lower insulating member 45 on the positive electrode side. Further, the first member 31 is arranged so that its back surface abuts against the surface on one end side in the longitudinal direction of the sealing plate 13 and the cylindrical portion 32 is inserted into the through hole 14, and the second member 35 is arranged so that the thin-walled portion 34 of the first member 31 is accommodated in the receiving portion 37 and an overlapping portion S is formed. Furthermore, the flat portion 25a is located in the space surrounded by the side wall portion 38 of the second member 35, and the positive electrode external terminal 25 is arranged so that the shaft portion 25b is inserted into the cylinder of the cylindrical portion 32 of the first member 31, the through hole 45a of the lower insulating member 45 on the positive electrode side, and the through hole 27c of the positive electrode current collecting terminal 27.

[0043] Before caulking, as shown in FIG. 6, for the positive electrode insulating gasket 30, the thickness Ta1 of the first plate-shaped portion 33 in the first member 31 is equal to or greater than the sum of the thickness Tb1 of the thin-walled portion 34 of the first member 31 and the thickness Tc1 of the protruding portion 39 of the second member 35 (Ta1≧Tb1+Tc1). Also, the thickness Td1 of the second plate-shaped portion 36 in the second member 35 is thinner than the thickness Ta1 of the first plate-shaped portion 33 (Ta1>Td1). Also, a gap 41 exists between the surface and end surface of the thin-walled portion 34 of the first member 31 and the inner surface of the receiving portion 37 of the second member 35.

[0044] In this state, the caulking portion 25c protruding downward from the terminal connection portion 27b of the positive electrode current collector terminal 27 is caulked. As a result, while the positive electrode insulating gasket 30 is compressed and deformed, the positive electrode external terminal 25 and the positive electrode current collector terminal 27 are physically joined and electrically connected to each other.

[0045] Note that after the caulking process, the cylindrical portion 32 is interposed in a compressed state between the shaft portion 25b of the positive electrode external terminal 25 and the inner peripheral surface of the through hole 14 of the sealing plate 13, and the first plate-like portion 33 is interposed in a compressed state between the back surface of the flat portion 25a of the positive electrode external terminal 25 and the front surface of the sealing plate 13. That is, the first member 31 is interposed in a compressed state between the shaft portion 25b of the positive electrode external terminal 25 and the inner peripheral surface of the through hole 14 of the sealing plate 13, and between the back surface of the flat portion 25a of the positive electrode external terminal 25 and the front surface of the sealing plate 13.

[0046] Here, the positive electrode insulating gasket 30 has a larger Young's modulus for the material constituting the second member 35 than for the material constituting the first member 31. Therefore, when the positive electrode insulating gasket 30 is compressed, the first member 31 having a relatively small Young's modulus deforms, and the thin portion 34 of the first member 31 deforms so as to fill the gap 41 between the receiving portion 37, and the thin portion 34 and the protruding portion 39 overlap in the vertical direction. That is, while the deformation of the first member 31 is received by the receiving portion 37 of the second member 35, an overlapping portion S in which a part of the first member 31 and a part of the second member 35 overlap in the vertical direction is formed.

[0047] Therefore, during the caulking process, the load on the second member 35 caused by the deformation of the first member 31 is relaxed, so that the deformation of the second member 35 is suppressed and damage to the positive electrode insulating gasket 30 is suppressed.

[0048] Also, even if the overlapping portion S is not formed and the end face of the first member 31 and the end face of the second member 35 simply come into contact with each other, no gap is generated between the first member 31 and the second member 35. However, in this case, the insulation distance (creepage distance) between the positive external terminal 25 and the sealing plate 13 when passing between the first member 31 and the second member 35 is only the thickness of the first member 31 and the second member 35. On the other hand, by having the overlapping portion S, no gap is generated between the first member 31 and the second member 35, and the insulation distance (creepage distance) between the positive external terminal 25 and the sealing plate 13 when passing between the first member 31 and the second member 35 becomes longer than when the overlapping portion S is not formed.

[0049] Therefore, in the sealing body 12, the occurrence of insulation failure due to damage to the positive insulation gasket 30 during caulking or insufficient insulation distance between the positive external terminal 25 and the sealing plate 13 is suppressed, and insulation between the positive external terminal 25 and the sealing plate 13 is ensured.

[0050] Also, after caulking, that is, the positive insulation gasket 30 assembled and compressed to the sealing plate 13, as shown in FIG. 3, the thickness Ta2 of the first plate-shaped portion 33 in the first member 31 is equal to the sum of the thickness Tb2 of the thin-walled portion 34 of the first member 31 and the thickness Tc2 of the protruding portion 39 of the second member 35 (in other words, the thickness of the overlapping portion S in the compressed state) (Ta2 = Tb2 + Tc2). Also, the thickness Td2 of the second plate-shaped portion 36 of the second member 35 is equal to or less than the sum of the thickness Ta2 of the first plate-shaped portion 33, the thickness Tb2 of the thin-walled portion 34, and the thickness Tc2 of the protruding portion 39 (Td2 ≦ Ta2, Tb2 + Tc2).

[0051] That is, in the sealing body 12 according to the present embodiment, the thin portion 34 of the first member 31 and the protruding portion 39 of the second member 35 overlap and are compressed in the vertical direction, and are sandwiched between the back surface of the flat portion 25a of the positive electrode external terminal 25 and the surface of the sealing plate 13. In other words, the overlapping portion S is sandwiched between the back surface of the flat portion 25a of the positive electrode external terminal 25 and the surface of the sealing plate 13. Therefore, it is difficult for the first member 31 to come out horizontally from within the receiving portion 37 of the second member 35 (in other words, in a direction parallel to the surface of the sealing plate 13), and it is difficult for the second member 35 to move horizontally.

[0052] In the present embodiment, as described above, the negative electrode side has the same configuration as the positive electrode side. Therefore, although detailed description is omitted, in the present embodiment, the negative electrode insulating gasket 40 and the negative electrode external terminal 26 are disposed on the upper surface side at the other end in the longitudinal direction of the sealing plate 13. Further, the negative electrode lower insulating member 46 and the negative electrode current collecting terminal 28 are disposed on the lower surface side at the other end in the longitudinal direction of the sealing plate 13, and the electrode connection portion 28a of the negative electrode current collecting terminal 28 is joined to the negative electrode terminal joining portion 22 of the electrode body 20, and the negative electrode current collecting terminal 28 and the electrode body 20 are electrically connected.

[0053] Also on the negative electrode side, when caulking the caulking portion of the negative electrode external terminal 26, the load on the second member caused by the deformation of the first member is relaxed and the deformation of the second member is suppressed, so that damage to the negative electrode insulating gasket 40 is suppressed. Further, since the negative electrode insulating gasket 40 has an overlapping portion, no gap is generated between the first member and the second member, and the insulation distance (creepage distance) between the negative electrode external terminal 26 and the sealing plate 13 is longer than when no overlapping portion is formed. Therefore, insulation between the negative electrode external terminal 26 and the sealing plate 13 is ensured. Furthermore, also on the negative electrode side, it is difficult for the first member to come out from within the receiving portion of the second member, and the movement of the second member along the horizontal direction is suppressed.

[0054] 〔Alternative Embodiment〕 〔1〕In the above-described embodiment, the mode in which the receiving portion 37 is formed at a position facing the end face of the first member 31 and also facing the surface of the sealing plate 13 has been described. However, the present invention is not limited to such a mode. A mode in which the receiving portion is formed at a position facing the back surface of the flat portion 25a of the positive electrode external terminal 25 may also be acceptable.

[0055] 〔2〕In the above-described embodiment, the mode in which the overlapping portion S is located between the back surface of the flat portion 25a of the positive electrode external terminal 25 and the surface of the sealing plate 13 has been described. However, the present invention is not limited to such a mode. For example, the overlapping portion may be located outside the flat portion 25a in a direction perpendicular to the surface of the flat portion 25a of the positive electrode external terminal 25 when viewed in a direction orthogonal to the surface of the flat portion 25a.

[0056] 〔3〕In the above-described embodiment, in a state where the positive electrode insulating gasket 30 is assembled to and compressed by the sealing plate 13, the thickness Ta2 of the first plate-like portion 33, the thickness Tb2 of the thin portion 34, the thickness Tc2 of the protruding portion 39, and the thickness Td2 of the second plate-like portion 36 satisfy "Ta2 = Tb2 + Tc2" and "Td2 ≤ Ta2, Tb2 + Tc2", so that the movement of the second member 35 along the surface of the sealing plate 13 is suppressed. However, the present invention is not limited to such a mode. For example, in the overlapping portion, the movement of the second member along the surface of the sealing plate may be suppressed by engaging the first member and the second member. FIG. 7 is a cross-sectional view showing an insulating gasket 50 according to another embodiment. For example, as shown in FIG. 7, an insulating gasket 50 may be configured by a first member 51 having a thin portion 52 with a recess 53 formed on its surface, and a second member 55 having a protruding portion 56 with a convex portion 57 protruding downward from the tip side of the lower surface. In this case, the convex portion 57 of the second member 55 fits into the recess 53 of the first member 51, so that the movement of the second member 55 in a direction parallel to the surface of the sealing plate is further suppressed.

[0057] Incidentally, the configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Also, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

Explanation of Reference Numerals

[0058] 1: Secondary battery 12: Sealing body 13: Sealing plate (lid body) 14, 15: Through hole (attachment port) 25: Positive electrode external terminal (battery terminal) 25a: Plane portion 25b: Shaft portion 26: Negative electrode external terminal (battery terminal) 26b: Shaft portion 30: Positive electrode insulating gasket (insulating and airtight member) 31: First member 32: Cylindrical portion 33: First plate-like portion 34: Thin portion 35: Second member 36: Second plate-like portion 37: Receiving portion 40: Negative electrode insulating gasket (insulating and airtight member) 41: Gap 50: Insulating gasket 51: First member 52: Thin portion 55: Second member S: Overlapping portion Ta1: Thickness of the first plate-like portion Ta2: Thickness of the first plate-like portion Tb1: Thickness of the thin portion Tb2: Thickness of the thin portion Tc1: Thickness of the protruding portion (thickness of the remaining portion after the receiving portion in the second plate-like portion is cut out) Tc2: Thickness of the protruding portion (thickness of the remaining portion after the receiving portion in the second plate-like portion is cut out) Td1: Thickness of the second plate-like portion Td2: Thickness of the second plate-like portion

Claims

1. A sealing body for a sealed secondary battery attached to an opening of a housing, comprising: a lid body having an attachment port penetrating through the front and back surfaces; a battery terminal having a flat portion and a shaft portion extending from the back surface of the flat portion, the shaft portion being inserted through the attachment port; an insulating and airtight member that insulates the battery terminal from the lid body and maintains airtightness between the shaft portion of the battery terminal and the attachment port of the lid body; The insulating and airtight member is: a first member interposed in a compressed state between the shaft portion of the battery terminal and the inner peripheral surface of the attachment port of the lid body, and between the back surface of the flat portion of the battery terminal and the front surface of the lid body; a second member made of a material having a higher Young's modulus than that of the first member and disposed at a position facing the end surface of the first member; The second member has a receiving portion for receiving deformation of the first member at a position facing the end surface of the first member and also facing the back surface of the flat portion of the battery terminal or the front surface of the lid body; A sealing body having an overlapping portion formed by a part of the end portion of the first member located within the receiving portion of the second member and a part of the second member overlapping in the vertical direction.

2. The overlapping portion is located between the back surface of the flat portion of the battery terminal and the front surface of the lid body, the thickness of the portion of the first member sandwiched between the back surface of the flat portion and the front surface of the lid body in the compressed state is the same as the thickness of the overlapping portion, and the thickness of the portion of the second member sandwiched between the back surface of the flat portion and the front surface of the lid body is less than or equal to the thickness of the portion of the first member sandwiched between the back surface of the flat portion and the front surface of the lid body and the thickness of the overlapping portion. The sealing body according to Claim 1.

3. The sealing body according to Claim 1 or 2, wherein the first member and the second member are engaged with each other in the overlapping portion.

4. An insulating and airtight member used for a sealing body for a secondary battery, comprising a lid body having an attachment port penetrating through the front and back surfaces, and a battery terminal having a flat portion and a shaft portion extending from the back surface of the flat portion and inserted into the attachment port, the insulating and airtight member insulating the battery terminal from the lid body and maintaining airtightness between the shaft portion of the battery terminal and the attachment port of the lid body. A cylindrical portion interposed between the shaft portion of the battery terminal and the inner peripheral surface of the mounting port of the lid body, a first plate-like portion extending from the outer peripheral surface of the cylindrical portion and interposed between the back surface of the flat portion of the battery terminal and the front surface of the lid body, and a thin-walled portion extending from the end surface of the first plate-like portion, a first member having; A second plate-like portion interposed between the back surface of the flat portion of the battery terminal and the front surface of the lid body, and a receiving portion formed at a position facing the end surface of the first plate-like portion in the second plate-like portion and facing the back surface of the flat portion of the battery terminal or the front surface of the lid body, the thin-walled portion of the first plate-like portion being received therein, a second member made of a material having a higher Young's modulus than that of the first member; A overlapping portion in which the second member and the thin-walled portion of the first member received in the receiving portion of the second member are arranged side by side in a direction parallel to the thickness direction of the first plate-like portion and the second plate-like portion; There is a gap between the thin-walled portion of the first member and the inner surface of the receiving portion; The thickness of the first plate-like portion is equal to or greater than the sum of the thickness of the thin-walled portion and the thickness of the remaining portion obtained by punching out the receiving portion in the second plate-like portion; An insulating and airtight member in which, in a state of being compressed along a direction parallel to the thickness direction of the first plate-like portion and the second plate-like portion and sandwiched between the back surface of the flat portion of the battery terminal and the front surface of the lid body, the thickness of the first plate-like portion is equal to the sum of the thickness of the thin-walled portion and the thickness of the remaining portion obtained by punching out the receiving portion in the second plate-like portion.

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