JP2016105374A - Sealed battery - Google Patents

Abstract

To provide a sealed battery having good sealing performance. A sealed battery 100 proposed here includes a battery case 20 having a terminal lead-out hole 22, an electrode terminal 30 having a rivet portion 32 projecting from a pedestal portion 34, a case 20, and an electrode terminal 30. And a sealing member 50 for sealing the gap. The seal member 50 includes a flat plate portion 54 that extends in a flat plate shape from one end of the cylindrical portion 52 in the outer diameter direction. The flat plate portion 54 is sandwiched between the inner surface 24 of the case 20 and the pedestal portion 34 of the electrode terminal 30. On the inner surface 24 of the case 20, a protrusion 26 is formed at a portion in contact with the flat plate portion 54. The tip of the rivet portion 32 is caulked at a constant pressure so as to compress the flat plate portion 54 in the terminal axis direction. [Selection] Figure 1

Description

  The present invention relates to a sealed battery such as a lithium ion secondary battery, and more particularly to a sealed battery having a structure in which a gap between an electrode terminal and a battery case is sealed with a sealing member.

  In recent years, lithium ion secondary batteries and other sealed batteries (for example, Patent Document 1) have become increasingly important as power sources for vehicles or power sources for personal computers, portable terminals, and the like. In particular, a lithium ion secondary battery that is lightweight and obtains a high energy density is preferably used as a high-output power source mounted on a vehicle.

JP 2012-028246 A

  As one typical configuration of a sealed battery, an electrode body and an electrolyte (typically a nonaqueous electrolyte) are accommodated in a battery case (exterior container), and an electrode terminal (at least one of a positive electrode terminal and a negative electrode terminal) is provided. The structure which penetrated the terminal extraction hole provided in the said case and was pulled out from the inside of this case is mentioned. The terminal lead hole is typically sealed by an annular seal member (gasket) interposed between a case wall surface surrounding the opening of the terminal lead hole and the electrode terminal (for example, Patent Document 1). ).

  As one of this type of seal structure, the seal structure shown in FIG. 5 has been studied. In the example of FIG. 5, the rivet portion 234 of the electrode terminal 230 is passed through the terminal lead-out hole 212 of the case 210, and the flat plate portion 222 of the seal member 220 is interposed between the inner surface 214 of the case 210 and the base portion 232 of the electrode terminal 230. Deploy. A flat plate portion of the seal member 220 is formed between the inner surface 214 of the case 210 and the pedestal portion 232 of the electrode terminal 230 by pressurizing and crimping the tip 234a of the rivet portion 234 in the terminal axis direction using a caulking jig. 222 is compressed. Thereby, the clearance between the case 210 and the electrode terminal 230 is closed, and the sealing property (airtightness) of the terminal lead hole 212 is ensured.

  However, in the structure shown in FIG. 5, the compression of the seal member 220 is performed by the flat plate portion 222, so the compression range is wide. Therefore, although the reaction force of the entire seal member 220 is large, there is a problem that the reaction force per unit area is small and sufficient sealing performance cannot be obtained.

  This invention is made | formed in view of this point, The main objective is to provide the sealed battery with favorable sealing performance.

  The sealed battery provided by the present invention is a battery case having a terminal lead hole and a rivet-shaped electrode terminal having a rivet portion protruding from a pedestal portion, and the rivet portion is a terminal of the case from the inside of the case. An electrode terminal provided so as to pass through the extraction hole, and a seal member provided between the case and the electrode terminal and sealing a gap between the case and the electrode terminal. The seal member includes a cylindrical portion attached to the outer periphery of the rivet portion, and a flat plate portion extending in a flat plate shape from one end of the cylindrical portion in the outer diameter direction. The flat plate portion is sandwiched between the inner surface of the case and the pedestal portion of the electrode terminal. At least one of the case inner surface and the pedestal portion has a protrusion formed at a portion in contact with the flat plate portion. The tip of the rivet portion is caulked at a constant pressure so as to compress the flat plate portion in the terminal axis direction. According to this configuration, a sealed battery with good sealing performance can be provided.

  In this specification, when defining the vertical direction, in the axial direction of the rivet terminal fixed to the battery case, the side where the rivet portion is located is defined as the upward direction, and the side where the pedestal portion is defined as the downward direction. . Further, in this specification, the “battery” is a term indicating a general power storage device capable of taking out electric energy, and is a concept including a primary battery and a secondary battery. In addition, the term “secondary battery” in the present specification includes a so-called storage battery such as a lithium ion secondary battery, a metal lithium secondary battery, a nickel metal hydride battery, and a nickel cadmium battery, and a storage element such as an electric double layer capacitor. It is. The technology disclosed herein is typically applied to a secondary battery and its manufacture.

It is a figure which shows typically the principal part cross section of the electrode terminal periphery of the battery which concerns on one Embodiment. It is a figure which shows typically the principal part cross section of the electrode terminal periphery of the battery which concerns on one Embodiment. It is a figure which shows typically the principal part cross section of the electrode terminal periphery of the battery which concerns on one Embodiment. It is a figure which shows the dimension of the battery which concerns on one Embodiment. It is a figure which shows typically the principal part cross section of the electrode terminal periphery of the conventional battery.

  Several preferred embodiments of the present invention are described below. Note that matters other than matters specifically mentioned in the present specification and necessary for the implementation of the present invention can be grasped as design matters of those skilled in the art based on the prior art in this field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

  Although not intended to be particularly limited, in the following, a wound electrode body (wound electrode body) and a non-aqueous liquid electrolyte (electrolyte solution) are accommodated in a flat rectangular (box-shaped) case. The present invention will be described in detail by taking as an example the case of manufacturing a sealed lithium ion secondary battery of the form. Moreover, in the following drawings, the same code | symbol is attached | subjected to the member and site | part which show | plays the same effect | action, and the overlapping description may be abbreviate | omitted or simplified.

  FIG. 1 and FIG. 2 show a cross section of the main part of a sealed battery 100 according to this embodiment. FIG. 2 is an enlarged view of the cross section of the main part of FIG. In FIG. 2, for the sake of convenience, the members 20, 50, 30 are illustrated with gaps. As shown in FIGS. 1 and 2, the sealed battery 100 includes a battery case 20, a first seal member (gasket) 50, and an electrode terminal 30. Further, a second seal member (gasket) 70 and an external terminal 40 are provided.

  The battery case (here, lid) 20 is a case for housing the electrode body 80 together with the electrolytic solution, and a terminal lead hole 22 is provided in a part thereof. The terminal lead hole 22 is a lead hole for pulling out the electrode terminal 30 from the inside of the case to the outside, and is provided so as to penetrate the outer surface and the inner surface 24 of the case 20. As a material which comprises the battery case 20, the thing similar to what is used with a general lithium ion secondary battery can be used suitably, and there is no restriction | limiting in particular. From the viewpoint of heat dissipation and the like, a metal (for example, aluminum) case 20 can be preferably used.

  The electrode terminal 30 is a rivet-shaped electrode terminal, and includes a pedestal portion 34 that extends outward from the outer shape of the terminal lead hole 22 and a rivet portion 32 that protrudes from the pedestal portion 34. The pedestal portion 34 is a plate-like member that spreads outward from the outer shape of the extraction hole 22 of the case 20, and a current collector 36 is attached to the lower surface thereof. The current collector 36 is electrically connected to the positive electrode or the negative electrode of the electrode body 80. Here, the pedestal 34 and the current collector 36 are integrally formed, but the pedestal 34 and the current collector 36 may be separated. The constituent material of the electrode terminal 30 is preferably a metal material having good conductivity, for example, aluminum.

  The rivet portion 32 is disposed so as to penetrate the terminal lead hole 22 from the inside of the case. The rivet portion 32 is caulked by radially expanding the tip of the rivet portion 32 and pushing it on the upper surface of the external terminal 40. A two-dot chain line in FIG. 1 represents the rivet portion 33 before caulking.

  The first seal member 50 and the second seal member 70 are respectively made of fluoro rubber (for example, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), vinylidene fluoride (FKM), tetrafluoroethylene-propylene ( FEPM), etc., ethylene-propylene rubber (EPM), ethylene-propylene-diene copolymer rubber (EPDM), butyl rubber and other elastic members having insulation properties. The first seal member 50 and the second seal member 70 are mounted in a gap between the electrode terminal 30 and the battery case 20 to insulate the electrode terminal 30 from the battery case 20 and to be mounted with the electrode terminal 30. The sealing property of the battery case 20 is ensured at the site.

  In this embodiment, the second seal member 70 is a substantially disk-shaped member disposed so as to cover the periphery of the terminal lead hole 22 outside the battery case 20.

  The first seal member 50 includes a cylindrical portion 52 and a flat plate portion 54. The cylinder portion 52 is provided at one end (upper end) of the first seal member 50. The flat plate portion 54 extends from one end (lower end) of the cylindrical portion 52 in a flat plate shape (in this embodiment, a disc shape) in the outer diameter direction. The cylindrical portion 52 of the first seal member 50 is mounted on the outer periphery of the rivet portion 32 of the electrode terminal 30 and is inserted into the terminal lead hole 22 together with the rivet portion 32 of the electrode terminal 30. The flat plate portion 54 of the first seal member 50 extends along the inside of the case 20 from the terminal lead hole 22 and is sandwiched between the inner surface 24 of the case 20 and the pedestal portion 34 of the electrode terminal 30.

  A protrusion 26 is formed on a portion of the inner surface 24 of the battery case 20 that is in contact with the flat plate portion 54 of the first seal member 50. In this embodiment, the protrusion 26 is formed in a ring shape along the periphery of the terminal lead hole 22. The tip of the protrusion 26 is chamfered.

  The electrode terminal 30, the first seal member 50, the second seal member 70, and the external terminal 40 are attached to the terminal lead hole 22 of the battery case 20.

Here, for example, the cylindrical portion 52 of the first seal member 50 is attached to the rivet portion 32 of the electrode terminal 30. Then, together with the first seal member 50, the rivet portion 32 of the electrode terminal 30 is inserted into the terminal lead-out hole 22 of the battery case 20 from the inside of the case 20. Then, the second seal member 70 is attached to the rivet portion 32 of the electrode terminal 30 protruding from the terminal lead hole 22 and disposed on the battery case 20. Further, the external terminal 40 is attached to the rivet portion 32 and disposed on the second seal member 70. In this state, using a caulking jig (for example, a rotary caulking machine having a rotating head), the tip of the rivet portion 32 is kept at a constant pressure (for example, 2500 N to 3000 N) so that the tip of the rivet portion 32 spreads to the outer diameter side. The electrode terminal 30 is caulked to the battery case 20 by crushing. Accordingly, the electrode terminal 30, the first seal member 50, the second seal member 70, and the external terminal 40 are attached to the terminal lead hole 22 of the battery case 20.
At that time, the flat plate portion 54 of the first seal member 50, the case 20, the second seal member 70, and the external terminal 40 are sandwiched and pressed between the caulking portion of the rivet portion 32 and the pedestal portion 34. The flat plate portion 54 of the first seal member 50 is compressed in the terminal axis direction, and the inner surface 24 of the case 20 and the pedestal portion 34 are in close contact with each other with the flat plate portion 54 interposed therebetween. Further, since the projection 26 is formed in the portion of the inner surface 24 of the case 20 that is in contact with the flat plate portion 54, the flat plate portion 54 is further compressed by the projection 26, and the high compression portion 56 is compressed to the flat plate portion 54. (FIG. 2) is formed. Thereby, the sealing property between the case 20 and the electrode terminal 30 is ensured.

  The sealed battery 100 according to the present embodiment includes a battery case 20 having a terminal lead-out hole 22 and a rivet-shaped electrode terminal 30 having a rivet portion 32 protruding from a pedestal portion 34, and the rivet portion 32 is a case. An electrode terminal 30 provided so as to penetrate the terminal lead hole 22 of the case 20 from the inside, and a first seal provided between the case 20 and the electrode terminal 30 to seal a gap between the case 20 and the electrode terminal 30 Member 50. The first seal member 50 includes a cylindrical portion 52 attached to the outer periphery of the rivet portion 32 and a flat plate portion 54 extending in a flat plate shape from one end (lower end) of the cylindrical portion 52 in the outer diameter direction. The flat plate portion 54 is sandwiched between the inner surface 24 of the case 20 and the pedestal portion 34 of the electrode terminal 30. On the inner surface 24 of the case 20, a protrusion 26 is formed at a portion in contact with the flat plate portion 54. The tip of the rivet portion 32 is caulked at a constant pressure so as to compress the flat plate portion 54 of the first seal member 50 in the terminal axis direction.

  According to this configuration, as shown in FIG. 2, the high compression portion 56 is formed on the flat plate portion 54 by the protrusions 26 formed on the inner surface 24 of the case 20, and a high reaction force C <b> 1 is obtained from the high compression portion 56. Therefore, sufficient sealing performance between the case 20 and the electrode terminal 30 can be ensured. Further, as shown in FIG. 3, even when the height of the protrusion 26 is lowered for some reason and the reaction force C1 from the high compression portion 56 becomes insufficient, the rivet portion 32 is caulked at a constant pressure. For this reason, the compression rate at a portion other than the high compression portion 56 is increased (the reaction force C2 is increased as the reaction force C1 is reduced), and the deterioration of the sealing performance can be compensated. Therefore, even when the reaction force C1 from the high compression part 56 becomes insufficient, the high sealing performance between the case 20 and the electrode terminal 30 can be maintained.

  Although it does not specifically limit as height H (FIG. 2) of protrusion 26, From a viewpoint of ensuring sealing performance, ratio (D of height H of protrusion 26 with respect to thickness D (FIG. 4) of the flat plate part 54 when not compressed) / H) is approximately 1/5 ≦ (D / H), preferably 1/4 ≦ (D / H), and particularly preferably 1/3 ≦ (D / H). is there. Although the upper limit of (D / H) is not particularly limited, it is preferable that (D / H) ≦ 1/2, and (D / H) ≦ 2/5 from the viewpoint of ease of compression and the like. preferable. A specific example of the thickness D of the flat plate portion 54 when uncompressed is approximately 0.3 mm to 1 mm, preferably 0.5 mm to 0.8 mm (for example, 0.6 mm). A specific example of the height H of the protrusion 26 is approximately 0.06 mm to 0.5 mm, preferably 0.1 mm to 0.3 mm (for example, 0.2 mm).

  The width W1 of the protrusion 26 (FIG. 2) is not particularly limited, but from the viewpoint of ensuring sealing performance, the ratio (W1 / W2) of the width W1 of the protrusion 26 to the width W2 of the flat plate portion 54 is approximately 1/10 ≦ ( W1 / W2) is appropriate, preferably 1/8 ≦ (W1 / W2), and particularly preferably 1/7 ≦ (W1 / W2). Although the upper limit of (W1 / W2) is not particularly limited, it is preferable that (W1 / W2) ≦ 1/5, and (W1 / W2) ≦ 1/6 from the viewpoint of ease of compression and the like. preferable. A specific example of the width W2 of the flat plate portion 54 is approximately 2 mm to 4 mm, preferably 2.5 mm to 3 mm (for example, 2.8 mm). A specific example of the width W1 of the protrusion 26 is approximately 0.2 mm to 0.8 mm, preferably 0.3 mm to 0.5 mm (for example, 0.4 mm).

  In this embodiment, as shown in FIG. 2, a step (further protrusion) 38 is formed on the pedestal 34 of the electrode terminal 30. The high compression portion 56 of the first seal member 50 can be further compressed by the step 38. The height of the step 38 is generally 0.05 mm to 0.3 mm, preferably 0.08 mm to 0.2 mm (for example, 0.1 mm). An example of the dimensions of the case 20, the electrode terminal 30, and the first seal member 50 is shown in FIG.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible.

20 battery case 22 terminal lead hole 24 inner surface 26 of battery case 30 protrusion 30 electrode terminal 32 rivet part 34 pedestal part 36 current collecting part 38 step 40 external terminal 50 first seal member 52 cylindrical part 54 flat part 56 high compression part 70 Second seal member 80 Electrode body 100 Sealed battery

Claims (1)

A battery case having a terminal lead hole;
A rivet-shaped electrode terminal having a rivet portion projecting from a pedestal portion, the rivet portion provided from the inside of the case so as to penetrate the terminal lead-out hole; and
A seal member provided between the case and the electrode terminal, and sealing a gap between the case and the electrode terminal;
The seal member includes a cylindrical portion attached to the outer periphery of the rivet portion, and a flat plate portion extending in a flat plate shape from one end of the cylindrical portion in the outer diameter direction,
The flat plate portion is sandwiched between the inner surface of the case and the base portion of the electrode terminal,
At least one of the inner surface of the case and the pedestal portion has a protrusion formed at a portion in contact with the flat plate portion,
A sealed battery in which a tip of the rivet portion is caulked at a constant pressure so as to compress the flat plate portion in a terminal axis direction.

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