JP7399148B2 - battery - Google Patents

Description

The present technology relates to batteries.

Conventionally, a structure has been adopted in which the electrolyte injection hole is sealed with a sealing member after the electrolyte is injected into the outer can of the battery. Such structures are described in, for example, JP-A-2011-76865 (Patent Document 1) and JP-A-2010-277936 (Patent Document 2). In the structures described in Patent Documents 1 and 2, the sealing member is caulked and fixed to the outer can.

Japanese Patent Application Publication No. 2011-76865 Japanese Patent Application Publication No. 2010-277936

When the sealing member is caulked and fixed to the outer can, it is required to realize a reliable sealing state in order to ensure the sealing performance of the outer can and prevent leakage of the electrolyte. An object of the present technology is to provide a battery in which an electrolyte injection hole can be reliably sealed by a sealing member.

The battery according to the present technology includes: an electrode body and an electrolyte; an outer can that houses the electrode body and the electrolyte and includes a liquid injection hole having a first diameter; and a sealing member for sealing. The sealing member includes a rivet member having a shaft portion inserted into the liquid injection hole, a flange portion located on the outside of the outer can in a radial direction of the shaft portion, and a rivet member that is compressed between the flange portion and the outer can. , and a ring-shaped washer member surrounding a central hole having a second diameter that is greater than or equal to the first diameter. The washer member has a cross-sectional area of 0.08 mm ² or more and 0.14 mm ² or less on one side of the central hole in a state before compression. The washer member is compressed over the entire radial direction of the washer member.

According to the present technology, a reliable sealed state can be achieved in a structure in which a sealing member that seals an electrolyte injection hole of a battery is caulked and fixed.

FIG. 2 is a perspective view of a prismatic secondary battery. 2 is a sectional view taken along line II-II in FIG. 1. FIG. FIG. 3 is a cross-sectional view showing the structure of a sealing member according to one embodiment. FIG. 3 is a cross-sectional view showing the structure of a sealing member according to a comparative example. 5 is a diagram (part 1) showing the structure around part A in FIG. 4. FIG. 5 is a diagram (part 2) showing the structure around section A in FIG. 4. FIG. 5 is a diagram (part 3) showing the structure around part A in FIG. 4. FIG. FIG. 5 is a diagram (part 4) showing the structure around part A in FIG. 4; It is a figure which shows the electrolyte injection process and the crimping process of a sealing member. FIG. 3 is a diagram (part 1) showing an example of the planar shape of the washer member before compression. FIG. 7 is a diagram (part 2) showing an example of the planar shape of the washer member before compression. FIG. 3 is a diagram (part 3) showing an example of the planar shape of the washer member before compression. FIG. 4 is a diagram (part 4) showing an example of the planar shape of the washer member before compression.

Embodiments of the present technology will be described below. Note that the same reference numerals may be given to the same or corresponding parts, and the description thereof may not be repeated.

In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc. unless otherwise specified. Furthermore, in the embodiments below, each component is not necessarily essential to the present technology unless otherwise specified.

In addition, in this specification, the descriptions of "comprise", "include", and "have" are in an open-ended format. That is, when a certain configuration is included, other configurations other than the particular configuration may or may not be included. Further, the present technology is not limited to necessarily achieving all the effects mentioned in this embodiment.

The battery according to this embodiment is typically a vehicle-mounted lithium ion secondary battery. However, in this specification, "battery" is not limited to lithium ion batteries, and may include other batteries such as nickel metal hydride batteries.

FIG. 1 is a perspective view of a prismatic secondary battery 1. FIG. 2 is a sectional view taken along line II-II in FIG.

As shown in FIGS. 1 and 2, the prismatic secondary battery 1 includes a battery case 100, an electrode body 200, an insulating sheet 300, a positive terminal 400, a negative terminal 500, a positive current collecting member 600, and a negative electrode. It includes a current collecting member 700, a cover member 800, and a sealing member 900.

The battery case 100 includes a rectangular exterior body 110 having an opening in the shape of a rectangular cylinder with a bottom, and a sealing plate 120 that seals the opening of the rectangular exterior body 110. It is preferable that the square exterior body 110 and the sealing plate 120 are each made of metal, and preferably made of aluminum or an aluminum alloy.

The sealing plate 120 is provided with an electrolyte injection hole 121 . After the electrolyte is injected into the battery case 100 from the electrolyte injection hole 121, the electrolyte injection hole 121 is sealed with a sealing member 900 (rivet).

The sealing plate 120 is provided with a gas exhaust valve 122 . Gas exhaust valve 122 breaks when the pressure within battery case 100 exceeds a predetermined value. As a result, the gas inside the battery case 100 is discharged to the outside of the battery case 100.

The electrode body 200 is housed in the battery case 100 together with the electrolyte. The electrode body 200 is made up of a positive electrode plate and a negative electrode plate laminated with a separator in between. A resin insulating sheet 300 is placed between the electrode body 200 and the rectangular exterior body 110.

A positive electrode tab 210A and a negative electrode tab 210B are provided at the end of the electrode body 200 on the sealing plate 120 side.

The positive electrode tab 210A and the positive electrode terminal 400 are electrically connected via the positive electrode current collecting member 600. The positive electrode current collector 600 includes a first positive electrode current collector 610 and a second positive electrode current collector 620. Note that the positive electrode current collecting member 600 may be composed of one component. The positive electrode current collecting member 600 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy.

Negative electrode tab 210B and negative electrode terminal 500 are electrically connected via negative electrode current collecting member 700. The negative electrode current collector 700 includes a first negative electrode current collector 710 and a second negative electrode current collector 720. Note that the negative electrode current collecting member 700 may be composed of one component. The negative electrode current collecting member 700 is preferably made of metal, and more preferably made of copper or a copper alloy.

The positive electrode terminal 400 is fixed to the sealing plate 120 via an external insulating member 410 made of resin. The negative electrode terminal 500 is fixed to the sealing plate 120 via an external insulating member 510 made of resin.

The positive electrode terminal 400 is preferably made of metal, more preferably aluminum or aluminum alloy. The negative electrode terminal 500 is preferably made of metal, and more preferably made of copper or a copper alloy. Negative electrode terminal 500 may have a region made of copper or copper alloy disposed inside battery case 100 and a region made of aluminum or aluminum alloy disposed outside battery case 100.

The cover member 800 is located between the first positive electrode current collector 610 and the electrode body 200. The cover member 800 may be provided on the negative electrode current collector side. Further, the cover member 800 is not an essential member and can be omitted as appropriate.

When manufacturing the prismatic secondary battery 1, the positive electrode terminal 400, the negative electrode terminal 500, the positive current collecting member 600, the negative current collecting member 700, and the cover member 800 are assembled to the sealing plate 120. On the other hand, the electrode body 200 is wrapped with an insulating sheet 300. The electrode body 200 and the insulating sheet 300 are inserted into the rectangular exterior body 110. Thereafter, the sealing plate 120 is welded and connected to the rectangular exterior body 110, and the opening of the rectangular exterior body 110 is sealed with the sealing plate 120, forming a sealed battery case 100.

Thereafter, the non-aqueous electrolyte is injected into the battery case 100 from the electrolyte injection hole 121 provided in the sealing plate 120. As the nonaqueous electrolyte, for example, one containing ethylene carbonate (EC), ethylmethyl carbonate (EMC), diethyl carbonate (DEC), and dimethyl carbonate (DMC) is used.

After the non-aqueous electrolyte is injected, the electrolyte injection hole 121 is sealed by the sealing member 900 through a pressure reduction process within the battery case 100. By carrying out the above steps, the prismatic secondary battery 1 is completed.

FIG. 3 is a cross-sectional view showing the structure of a sealing member 900 according to this embodiment. As shown in FIG. 3, the sealing member 900 includes a rivet member 910, a mandrel member 920, and a washer member 930.

The rivet member 910 is typically made of metal, but is not limited thereto. The rivet member 910 includes a collar portion 911, a shaft portion 912, and a caulking fixing portion 913.

The flange portion 911 faces the outer surface of the sealing plate 120. The flange portion 911 is located on the outside of the battery case 100 in the radial direction of the shaft portion 912 .

The shaft portion 912 has an outer diameter that is the same as or slightly smaller than the hole diameter (first diameter) of the electrolyte injection hole 121 . The shaft portion 912 is inserted into the electrolyte injection hole 121. A caulking fixing portion 913 is formed at the root portion of the shaft portion 912 . The sealing member 900 including the rivet member 910 is fixed to the sealing plate 120 by the caulking fixing portion 913 .

Mandrel member 920 is typically made of metal, but is not limited thereto. Mandrel member 920 includes an engaging portion 921 and a cutting portion 922.

The engaging portion 921 engages with the shaft portion 912 of the rivet member 910. The cut portion 922 is a portion where the mandrel member 920 is cut in the process of forming the caulking fixing portion 913. By providing the mandrel member 920 with a weakened portion in advance, the position of the cutting portion 922 can be determined.

The washer member 930 is made of a material having lower hardness than the rivet member 910 (for example, fluororesin such as PFA, polypropylene, etc.). The washer member 930 is compressed between the flange portion 911 of the rivet member 910 and the sealing plate 120. Thereby, the space between the flange portion 911 and the sealing plate 120 can be sealed by the washer member 930.

Washer member 930 has a ring shape. The diameter (second diameter) of the ring-shaped central hole is the same as or slightly larger than the diameter (first diameter) of the electrolyte injection hole 121 . That is, the inner diameter of washer member 930 is greater than or equal to the hole diameter of electrolyte injection hole 121 .

The washer member 930 has a cross-sectional area of about 0.08 mm ² or more and 0.14 mm ² or less on one side of the central hole (one of the two cross sections of the washer member 930 shown in FIG. 3) in a state before compression. After compression, the cross-sectional area of washer member 930 varies slightly along the circumferential direction, but the average cross-sectional area of washer member 930 over the entire circumferential direction is almost equal to the cross-sectional area of washer member 930 before compression. It does not change.

The washer member 930 is compressed between the flange portion 911 of the rivet member 910 and the sealing plate 120 over the entire radial direction of the washer member 930 . Thereby, the sealing performance by the washer member 930 can be stably obtained.

FIG. 4 is a cross-sectional view showing the structure of a sealing member 900 according to a comparative example. The basic structure of the comparative example shown in FIG. 4 is also the same as that shown in FIG. 3. That is, the rivet member 910A includes a collar portion 911A, a shaft portion 912A, and a caulking fixing portion 913A, and the mandrel member 920A includes an engaging portion 921A and a cutting portion 922A.

However, in the comparative example shown in FIG. 4, the rivet member 910A includes a rib 914A that protrudes toward the sealing plate 120 from the lower surface of the collar portion 911A. The washer member 930A is compressed between the rib 914A of the rivet member 910A and the sealing plate 120. That is, the washer member 930A is locally compressed below the rib 914A.

5 to 8 are diagrams showing the structure around section A in the comparative example of FIG. 4. As described above, the washer member 930A is compressed at the lower part of the rib 914A, but due to dimensional variations due to manufacturing errors of the rivet member 910A, the compression of the washer member 930A is insufficient, and the seal by the washer member 930A is There may be cases where sufficient quality cannot be ensured.

Specifically, for example, if the height of the rib 914A (H in FIG. 5) is not sufficient, the compression of the washer member 930A may not be sufficient. Furthermore, in the R portion 915A formed at the boundary between the flange portion 911A and the shaft portion 912A of the rivet member 910A, if the actual line 915A2 protrudes from the design line 915A1, for example, as shown in FIG. If the formation angle θ of the R portion 915A is smaller than 90° as shown in FIG. When 930A is compressed, the washer member 930A escapes from the rib 914A in the direction of the shaft portion 912A and in the outward direction from the rib 914A. Therefore, due to the above-mentioned downward fall of the R portion 915A, the volume between the rib 914A and the shaft portion 912A decreases, and the escape allowance of the washer member 930A when compressing the washer member 930A decreases. As a result, the volume between the rib 914A and the shaft portion 912A is filled with the escaped washer member 930A, and the washer member 930A is insufficiently compressed below the rib 914A.

On the other hand, if the load that presses the rivet member 910A toward the sealing plate 120 side is excessively increased to ensure compression of the washer member 930A, the amount of deformation of the sealing plate 120 increases, or the sealing plate 120 deforms from the rectangular exterior body 110. Events such as tilting against the surface may occur.

In contrast, in the sealing member 900 according to the present embodiment, the washer member 930 is compressed between the flange 911 of the rivet member 910 and the sealing plate 120 over its entire radial direction, so that the rivet member The washer member 930 can be compressed uniformly in the circumferential direction without being affected by variations in the dimensions of the washer member 910. Further, the cross-sectional area of the washer member 930 located on one side of the central hole (one side of the two cross sections of the washer member 930 shown in FIG. 3) in the state before compression is approximately 0.08 mm ² or more and 0.14 mm ² or less. By doing so, the washer member 930 can be sufficiently compressed without excessively increasing the load that presses the rivet member 910 toward the sealing plate 120 side. As a result of the above, it is possible to appropriately compress the washer member 930 and ensure sealing performance.

FIG. 9 is a diagram showing an electrolyte injection process and a sealing member caulking process. As shown in FIG. 9A, the electrolytic solution 200A is injected into the battery case 100 using the injecting nozzle 10 (injection step).

After the electrolytic solution 200A injection process, the sealing member 900 is caulked. As shown in FIG. 9(b), a sealing member 900 is assembled to the sealing plate 120. At this time, the rivet member 910 of the sealing member 900 is inserted into the battery case 100 of the sealing plate 120. A caulking jig 20 is provided on the sealing member 900. The caulking jig 20 includes a jaw 21 and a head 22.

As shown in FIG. 9(c), the mandrel member 920 of the sealing member 900 is held by the jaw 21 provided within the head 22. From this state, the jaw 21 is pulled upward in the figure. When pulling up the mandrel member 920, the rivet member 910 is pressed downward in the figure by the tip of the caulking jig 20.

Thereby, as shown in FIG. 9(d), the rivet member 910 is caulked and fixed to the sealing plate 120, and the mandrel member 920 is cut inside the rivet member 910. Further, the washer member 930 is pressed, and the space between the rivet member 910 and the sealing plate 120 is sealed by the washer member 930.

It is preferable that the washer member 930 has a thickness (first thickness) of about 0.3 mm or more and 0.5 mm or less in a state before compression. The thickness (second thickness) of washer member 930 compressed between rivet member 910 and sealing plate 120 is about 35% or more and 65% or less of the thickness before compression (first thickness).

FIG. 10 is a diagram showing an example of the planar shape of the washer member 930 before compression. The washer member 930 may have a circular ring shape as shown in FIG. 10, or a polygonal ring shape as shown in FIGS. 11 and 12. Further, as shown in FIG. 13, it may have a ring shape in which a part of the circumferential direction (in the example of FIG. 13, a substantially square corner) is bent inward.

As mentioned above, if the cross-sectional area of the washer member 930 before compression is approximately 0.08 mm ² or more and 0.14 mm ² or less, if the thickness of the washer member 930 before compression is approximately 0.3 mm, then , the width of the ring-shaped washer member 930 (B in FIGS. 10 to 13) is about 0.3 mm or more and 0.45 mm or less, and when the thickness of the washer member 930 before compression is about 0.5 mm, The width of the ring-shaped washer member 930 (B in FIGS. 10 to 13) is about 0.2 mm or more and 0.25 mm or less.

The mechanical properties of washer member 930 are adjusted while taking sealing performance into consideration. For example, when using the washer member 930 made of PFA, the tensile strength is approximately 25 MPa or more and 35 MPa or less, the elongation rate is approximately 300% or more and 350% or less, and the compressive strength is approximately 15 MPa or more and 20 MPa or less. , Rockwell hardness (R scale) is about R50, Shore hardness (D scale) is about D62 or more and D65, flexural modulus is about 540 MPa or more and 640 MPa or less, and tensile modulus is about 310 MPa or more and 350 MPa or less. It is preferable that However, the physical properties of washer member 930 are not limited to these ranges.

On the other hand, when using the washer member 930 made of polypropylene, the tensile strength is approximately 31 MPa or more and 41 MPa or less, the elongation rate is approximately 100% or more and 600% or less, and the compressive strength is approximately 38 MPa or more and 55 MPa or less. , Izod impact strength is about 22 J/m or more and 75 J/m or less, Rockwell hardness (R scale) is about R85 or more and R110 or less, flexural modulus is about 41 MPa or more and 55 MPa or less, and tensile modulus is about 41 MPa or more and 55 MPa or less. It is preferably about 1100 MPa or more and 1600 MPa or less. However, the physical properties of washer member 930 are not limited to these ranges.

Although the embodiments of the present technology have been described above, the embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and it is intended that all changes within the meaning and range equivalent to the claims are included.

1 square secondary battery, 10 liquid injection nozzle, 20 caulking jig, 21 jaw, 22 head, 100 battery case, 110 square exterior body, 120 sealing plate, 121 electrolyte injection hole, 122 gas discharge valve, 200 electrode body , 200A electrolytic solution, 210A positive electrode tab, 210B negative electrode tab, 300 insulation sheet, 400 positive electrode terminal, 410 external insulation member, 500 negative electrode terminal, 510 external insulation member, 600 positive electrode current collector, 610 first positive electrode current collector , 620 second positive electrode current collector, 630 insulating member, 700 negative electrode current collector, 710 first negative electrode current collector, 720 second negative electrode current collector, 730 insulating member, 800 cover member, 900,900A sealing member, 910,910A rivet member, 911,911A flange, 912,912A shaft, 913,913A caulking fixing part, 914A rib, 915A R part, 915A1 design line, 915A2 actual line, 916A falling part, 920,920A mandrel member, 921,921A engaging portion, 922,922A cutting portion, 930,930A washer member.

Claims (6)

an electrode body and an electrolyte;
an exterior can that houses the electrode body and the electrolyte and includes a liquid injection hole having a first diameter;
a sealing member that is caulked and fixed to the outer can and seals the liquid injection hole,
The sealing member is
a rivet member having a shaft portion inserted into the liquid injection hole; and a flange portion located outside the outer can in a radial direction of the shaft portion;
a ring-shaped washer member that is compressed between the flange and the outer can and surrounds a central hole having a second diameter that is greater than or equal to the first diameter;
The washer member has a cross-sectional area of 0.08 mm ² or more and 0.14 mm ² or less on one side of the central hole in a state before compression,
The battery, wherein the washer member is compressed over the entire radial direction of the washer member. The washer member has a first thickness in a state before compression, and is compressed to a second thickness between 35% and 65% of the first thickness between the flange and the outer can. The battery according to claim 1. The battery according to claim 1 or 2, wherein the washer member has a thickness of 0.3 mm or more and 0.5 mm or less in a state before compression. The battery according to any one of claims 1 to 3, wherein the washer member is made of fluororesin. The exterior can includes a main body having an opening and accommodating the electrode body, and a sealing plate coupled to the main body, and the liquid injection hole is formed in the sealing plate. 4. The battery according to any one of 4. The battery according to any one of claims 1 to 5, wherein the battery is a lithium ion battery, and the outer can has a prismatic shape.

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