JP2013143332A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery which inhibits the occurence of welding failure.SOLUTION: In a battery according to one embodiment of this invention, a welding part A is formed at butting parts between a battery case 2 and a lid 3, and the battery case 2 and the lid 3 are joined to each other. The battery includes a groove 6 in at least a part of the butting part in the battery case 2, which butts to the lid 3, and the butting part in the lid 3, which butts to the battery case 2. The welding part A reaches the groove 6. It is preferable that an angle formed by the welding part A and the groove 6 is 90 degrees or larger. Further, it is preferable that the welding part A reaches a side part 6a of the groove 6.

Description

  The present invention relates to a battery, and more particularly to a battery that is joined by forming a welded portion at a butt portion between a battery case and a lid.

  In recent years, lithium ion batteries, nickel metal hydride batteries, and other secondary batteries (storage batteries) have become increasingly important as on-vehicle power supplies, or personal computers and portable terminals. The secondary battery has a configuration in which, for example, a battery case containing an electrode body and an electrolytic solution is sealed with a lid.

  Here, in the battery of Patent Document 1, a recessed portion capable of storing molten metal generated during welding of the battery case and the lid is formed in a path extending from the welded portion to an accommodation space such as an electrode body in the battery case. . Thereby, it is suppressed that a molten metal flows in accommodation space, such as an electrode body in the said battery case, at the time of welding of a battery case and a cover.

JP 2008-159536 A

  In the battery of Patent Document 1, gas generated during welding of the battery case and the lid may remain in the welded portion. That is, welding failure may occur.

  An object of the present invention is to solve such a problem, and is to provide a battery capable of suppressing the occurrence of poor welding.

  A battery according to an embodiment of the present invention is a battery that is joined by forming a welded portion at a butt portion between a battery case and a lid, and the butt portion with the lid in the battery case or the battery in the lid. A groove portion is provided in at least a part of the abutting portion with the case, and the welded portion reaches the groove portion.

In the battery, it is preferable that an angle formed by the welded portion and the groove portion is 90 ° or more.
In the battery, it is preferable that the welded portion reaches a side portion of the groove portion.

  In the battery described above, it is preferable that the groove portion has a different shape between the central portion of the long side and the other portion of the battery.

  In the battery described above, it is preferable that a cross-sectional area of the groove portion in a central portion of the long side of the battery is larger than a cross-sectional area of the groove portion in another portion of the battery.

  In the battery, the groove is formed over the entire circumference of the butted portion of the battery case with the lid, or the butted portion of the lid with the battery case, and the welded portion extends over the entire circumference. It is preferable to reach the groove.

  As described above, according to the present invention, it is possible to provide a battery capable of suppressing the occurrence of poor welding.

It is a perspective view which shows a general battery schematically. It is a figure which shows the manufacturing method of a general battery, and shows the state before joining a battery case and a lid | cover. It is a figure which shows the general battery manufacturing method, and shows the state at the time of joining a battery case and a lid | cover. It is an enlarged view which shows notionally the butting | matching part of the battery case and welding before welding in the battery which concerns on Embodiment 1 of this invention. It is an enlarged view which shows roughly the butt | matching part of the battery case and lid | cover after welding in the battery which concerns on Embodiment 1 of this invention. It is a figure explaining the angle formed by the outer peripheral surface of a welding part, and a groove part in the battery which concerns on Embodiment 1 of this invention. It is a figure explaining each site | part of the battery which concerns on Embodiment 2 of this invention. It is a figure which shows the arrangement | positioning and shape difference of the groove part formed in the long side center part, and the groove part formed in another part in the battery which concerns on Embodiment 2 of this invention. It is an enlarged view which shows roughly the butting | matching part of the battery case and a cover in the battery which concerns on other embodiment of this invention. It is an enlarged view which shows schematically the butting | matching part of a different battery case and a cover in the battery which concerns on other embodiment of this invention. It is a figure which shows schematically the groove part formed in the lid | cover in the battery which concerns on other embodiment of this invention. It is a figure which shows schematically the groove part formed in the battery case in the battery which concerns on other embodiment of this invention. It is an enlarged view which shows roughly the butting | matching part of a battery case and a lid | cover when the battery case and a lid | cover are welded by the vertical strike in the battery which concerns on other embodiment of this invention. It is an enlarged view which shows roughly the butting | matching part of a different battery case and a lid | cover when the battery case and a lid | cover are welded by the vertical strike in the battery which concerns on other embodiment of this invention.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

<Embodiment 1>
The battery according to the present embodiment is suitably used as, for example, a lithium ion battery, a nickel metal hydride battery, or another sealed battery.
Here, the structure of a general battery will be described first. As shown in FIG. 1, the battery includes an electrode body 1, a battery case 2, a lid 3, a positive electrode external terminal 4, and a negative electrode external terminal 5.

  The electrode body 1 is accommodated in the case 2 together with an electrolytic solution (not shown). As the electrode body 1, an electrode body similar to a general sealed battery can be used. That is, although not shown, the electrode body 1 includes a positive electrode sheet, a negative electrode sheet, and a separator.

  Specifically, the positive electrode sheet and the negative electrode sheet are wound in a state of being laminated together with the separator. More specifically, the coated portion in which the positive electrode active material is applied to the current collector foil in the positive electrode sheet and the coated portion in which the negative electrode active material is applied to the current collector foil in the negative electrode sheet and the separator are densely wound. The uncoated portion of the positive electrode sheet and the uncoated portion of the negative electrode sheet protrude from the core portion. The positive external terminal 4 is electrically connected to the uncoated portion of the positive electrode sheet. The negative external terminal 5 is electrically connected to the uncoated part of the negative electrode sheet.

  The battery case 2 contains the electrolyte and the electrode body 1. The battery case 2 is sealed with a lid 3. A positive external terminal 4 and a negative external terminal 5 protrude from the upper surface of the battery case 2. Incidentally, the lid 3 is formed with an inlet for injecting an electrolytic solution. The injection port is closed by a safety valve 31.

  The positive electrode external terminal 4 is electrically connected to an uncoated portion of the positive electrode sheet. Moreover, the negative electrode external terminal 5 is electrically connected to the uncoated part of the negative electrode sheet.

  Such a battery is manufactured as follows. First, as shown in FIG. 2, the electrode body 1 is electrically connected to the positive external terminal 4 and the negative external terminal 5 of the lid 3. Then, as shown in FIG. 3, the electrode body 1 is inserted into the battery case 2 and the battery case 2 is closed with a lid 3. Further, the butted portion between the battery case 2 and the lid 3 is welded to form a sealed structure. Finally, when the battery case 2 is filled with the electrolytic solution, the battery is completed.

  Here, when welding the abutting portion between the battery case 2 and the lid 3, there is a possibility that a melted gas is generated by welding energy or a shielding gas is accumulated in the welded portion, resulting in poor welding. Therefore, in the battery according to the present embodiment, as shown in FIG. 4, the groove 6 is formed in the abutting portion of the lid 3 with the battery case 2.

  Specifically, the lid 3 includes a fitting portion 32 into which the upper end portion of the battery case 2 is fitted along the outer peripheral edge portion. A groove portion 6 is formed in a portion 32 a that abuts the upper surface 21 of the battery case 2 in the fitting portion 32.

  The groove 6 accommodates a gas that is generated when the butted portion between the battery case 2 and the lid 3 is welded. The groove 6 of the present embodiment is formed along the outer peripheral edge of the lid 3, for example, over the entire circumference or partially. The groove 6 has a trapezoidal cross-sectional shape. However, the cross-sectional shape of the groove 6 is not particularly limited.

  As shown in FIG. 5, the groove 6 is disposed at a position where the weld A (hatched portion in FIG. 5) reaches. Thereby, the gas accumulated on the outer side of the battery case 2 in the welded part A escapes from the exposed surface A1 on the outer side of the battery case 2 in the welded part A. On the other hand, the gas accumulated on the inner side of the battery case 2 in the welded portion A escapes from the exposed surface on the inner side of the battery case 2 in the welded portion A, that is, the surface A2 exposed in the grooved portion 6, Is housed in.

  Therefore, the gas generated when welding the butted portion of the battery case 2 and the lid 3 can be satisfactorily extracted from the welded portion A, and poor welding can be prevented. Therefore, the strength of the welded portion between the battery case 2 and the lid 3 can be improved.

  And since the groove part 6 is a cavity part, the penetration depth D can be earned with the same welding energy, and the battery case 2 and the lid | cover 3 can be welded with less welding energy compared with the past.

  Incidentally, laser welding is preferably used as a welding method between the battery case 2 and the lid 3, but if the welding gas is a melt gasified by welding energy or a welding method in which shield gas is accumulated in the welded portion, the present method is used. It can be used when manufacturing the battery of the embodiment.

  The welded portion A does not have to reach the entire circumference of the outer peripheral edge portion of the lid 3 or the entire region of the groove portion 6 that is partially formed. It ’s fine. In other words, the welded part A may have a part that does not reach the groove part 6.

  Here, as shown in FIG. 6, it is preferable that the angle θ formed by the exposed surface A2 of the welded portion A and the groove portion 6 is larger than 90 °. In the present embodiment, the exposed surface of the welded part A is formed by forming the grooved part 6 so that the exposed surface A2 of the welded part A reaches the side part 6a of the grooved part 6 and does not reach the bottom part 6b of the grooved part 6. The angle θ formed by A2 and the groove 6 is configured to be larger than 90 °.

  With such a configuration, when the internal pressure of the battery case 2 increases, stress concentration on the contact end portion B between the exposed surface A2 of the welded portion A and the groove portion 6 can be prevented. Therefore, damage to the welded part A can be prevented. However, the shape and arrangement of the groove 6 are appropriately set according to welding conditions such as welding energy and the material of the base material.

<Embodiment 2>
The groove portion 6 of the battery according to the first embodiment is not particularly referred to the relationship between the formation position and shape in the battery, but preferably has the following relationship between the formation position and shape in the battery. .

  That is, as shown in FIG. 7, when each part of the battery is defined as a long side central part, a long side end part, an R part, and a short side part, the long side central part and the long side end part which are other parts The groove portion 6 is preferably formed so that the shape of the groove portion 6 is different between the R portion and the short side portion.

  Here, when the pressure inside the battery case 2 rises, a larger stress acts on the welded portion at the center of the long side of the battery than the welded portion at the other portion. For this reason, the welded portion at the center of the long side of the battery needs to secure a deeper penetration depth than the welded portion at the other portion, and the battery case 2 and the lid 3 need to be firmly joined. In other words, the battery case 2 and the lid 3 are welded at the center of the long side of the battery with higher welding energy than other parts.

  Therefore, in this embodiment, as shown in FIG. 8, the groove 6 (indicated by a broken line in FIG. 8) formed at the center of the long side of the battery is the groove 6 ( In FIG. 8, it is indicated by a solid line), and is formed on the inner side of the battery case 2 and has a large cross-sectional area.

  Thereby, even if welding energy is changed according to each site | part of a battery, the gas produced at the time of welding with the battery case 2 and the lid | cover 3 can be favorably accommodated in the groove part 6, and a welding defect can be suppressed.

<Other embodiments>
Although the groove part 6 of the said Embodiment 1 and 2 was formed in the butt | matching part with the battery case 2 in the lid | cover 3, you may form in the butt | matching part with the lid | cover 3 in the battery case 2, as shown in FIG. . Further, as shown in FIG. 10, the groove 6 may be formed in both the butted portion of the lid 3 with the battery case 2 and the butted portion of the battery case 2 with the lid 3.

  The grooves 6 of the first and second embodiments are formed in a trapezoidal cross section, but may be formed in a triangular shape as shown in FIGS. In short, it is only necessary that the gas generated when the battery case 2 and the lid 3 are welded can be satisfactorily stored.

  In the first and second embodiments, the battery case 2 and the lid 3 are welded by a so-called lateral strike (that is, a form in which the battery case 2 and the lid 3 are welded from the lateral direction), as shown in FIGS. 13 and 14. Thus, you may weld the battery case 2 and the lid | cover 3 by what is called a vertical strike (namely, the form which welds the battery case 2 and the lid | cover 3 from a vertical direction). Also in this case, as shown in FIG. 13 and FIG. 14, the groove 6 is formed at the abutting portion of the battery case 2 with the lid 3 or the abutting portion of the lid 3 with the battery case 2.

  Also in these forms, the groove part 6 should just be formed in at least one part of the butted part of the battery case 2 and the lid | cover 3, and the welding part A should just reach | attain at least one part of the groove part 6, substantially. Similar effects can be obtained.

  The embodiment of the battery according to the present invention has been described above. However, the present invention is not limited to the above configuration, and can be changed without departing from the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 Electrode body 2 Battery case, 21 Upper surface 3 Cover, 31 Safety valve 32 Fitting part, 32a Butting part 4 Positive electrode external terminal 5 Negative electrode external terminal 6 Groove part, 6a Side part of groove part, 6b Bottom part of groove part A Welding part A1 of welding part Exposed surface A2 Exposed surface B of welded part Contact end part of welded part and groove part

Claims (6)

A battery that is joined by forming a welded portion at the butt portion between the battery case and the lid,
A butt portion with the lid in the battery case, or a groove portion at least part of a butt portion with the battery case in the lid,
The battery where the weld reaches the groove.   The battery according to claim 1, wherein an angle formed by the welded portion and the groove portion is 90 ° or more.   The battery according to claim 1, wherein the welded portion reaches a side portion of the groove portion.   The battery according to any one of claims 1 to 3, wherein the groove portion has a different shape between a central portion of the long side and another portion of the battery.   5. The battery according to claim 4, wherein a cross-sectional area of the groove in the central portion of the long side of the battery is larger than a cross-sectional area of the groove in the other part of the battery. The groove is formed over the entire circumference of the butted portion of the battery case with the lid, or the butted portion of the lid with the battery case,
The battery according to any one of claims 1 to 5, wherein the welded part reaches the groove part over the entire circumference.

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