JP2015111573A - Battery and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery configured to prevent a member on a lid member from being burnt due to plume generated during welding, and a manufacturing method thereof.SOLUTION: A battery includes an external terminal member and an insulation member 180 arranged on an outer face of a lid member 113. A distance between insulation member 180 and the lid member 113 is smaller on a long side than on a short side of the lid member 113. A welding mark 160 formed from an outer face 113e of the lid member 113 to an opening end face of a battery case body 111 is formed on the whole circumference of the lid member 113. The welding mark 160 is formed not only on the outer face 113e of the lid member 113 and the opening end face of the battery case body 111, but also on an outside surface 111s of the battery case body 111, in a section facing the insulation member 180, on the long side of the lid member 113. In the other sections, the mark is formed from the outer face 113e of the lid member 113 to the opening end face of the battery case body 111, and not formed on the outside surface 111s of the battery case body 111.

Description

The present invention relates to a battery in which a power generation element is enclosed in a flat battery case and a method for manufacturing the same. More specifically, an external terminal member that is connected to the power generation element and functions as an external terminal is provided through the lid member of the battery case, and an insulating member that insulates the external terminal member from the lid member is a lid member. The present invention relates to a battery disposed on the outer surface side of the battery and a manufacturing method thereof.

An example of a conventional battery is described in Patent Document 1. The battery shown in FIG. 2 of the same document has a flat overall shape by fitting a “sealing plate 31” into an opening of an “exterior can 10” that is open on one side. A “spiral electrode body 20” is accommodated inside the outer can 10. In this battery, the sealing plate 31 is fixed to the outer can 10 by welding the boundary between the opening end surface of the outer can 10 and the sealing plate 31. This welding is performed by irradiating the “laser beam 50” from above on the welding location.

JP 2000-268781 A

However, the technique disclosed in Patent Document 1 has the following problems. Patent Document 1
As shown in FIG. 2, the sealing plate 31 is provided with a “pole terminal 32” and a “gasket 33” surrounding it. And since the external shape of a battery is flat shape, there exists a location with little space | interval between a welding location and the gasket 33. FIG. Therefore, the gasket 33 may be damaged due to the heat of welding during welding. In particular, depending on the type of battery, an insulator corresponding to the gasket 33 may be provided so as to protrude outward from the outer surface of the lid member corresponding to the sealing plate 31. Particularly in such a case, the insulator may be burned by being beaten by a plume (metal vapor or plasma) coming out of the melting point during welding. This leads to deterioration of the insulating material and causes failure of insulation and sealing.

The present invention has been made to solve the above-described problems of the prior art.
That is, an object of the present invention is to provide a battery and a method for manufacturing the same in which the member on the lid member is not burned by the plume during welding.

The battery of the present invention, which has been made for the purpose of solving this problem, has a shape having a flat battery case body with a built-in power generation element and an opening on one side, a long side part and a short side part. An external terminal member provided through the lid member and connected to the power generation element in the battery case body and partially exposed to the outside, and at least the lid member. And an insulating member that insulates the external terminal member from the lid member. In the battery of the present invention, the interval between the edge of the insulating member and the long side of the lid member is smaller than the interval between the edge of the insulating member and the short side of the lid member, and the lid member is fitted into the opening of the battery case body. The weld mark extending over the outer surface of the lid member and the opening end surface of the battery case body is formed over the entire circumference of the lid member, so that the lid member is fixed to the battery case body and the interior of the battery case body is The section that is sealed from the outside and faces at least the insulating member on the long side of the lid member has weld marks not only on the outer surface of the lid member and the opening end surface of the battery case body but also on the outer surface of the battery case body. This is a wide welding mark section formed so as to extend.

The battery manufacturing method according to the present invention includes a flat battery case body having a built-in power generation element and one of which is open, a shape having a long side portion and a short side portion, and a lid member that closes the opening portion of the battery case body. The battery of interest is an external terminal member provided through the lid member that is connected to the power generation element in the battery case body and is partially exposed to the outside. And an insulating member that is disposed at least on the outer surface side of the lid member and insulates the external terminal member from the lid member, and the interval between the edge of the insulating member and the long side of the lid member is such that the edge of the insulating member and the lid member It is smaller than the distance from the short side. In the manufacturing method of the present invention, the lid member is fitted into the opening of the battery case body without covering the opening end face of the battery case body, and the boundary between the outer surface of the lid member and the opening end face of the battery case body is covered with the lid member. The lid member is fixed to the battery case main body and the inside of the battery case main body is sealed from the outside world. In at least the section of the long side of the lid member that faces the insulating member, the welding trace is not only on the outer surface of the lid member and the opening end surface of the battery case body, but also on the outer surface of the battery case body. The first level energy is formed to extend, and the second level energy equal to or lower than the first level is used in sections other than the section where welding with the first level energy is performed.

By so doing, when welding the section facing the insulating member in the long side of the lid member, the plume is ejected with an inclination toward the outside by welding at the first level energy (large energy). For this reason, deterioration of the insulating member etc. by the plume at the time of welding is prevented. By this high energy welding, a wide weld mark section is formed.

Here, the section other than the wide welding mark section includes a section on the short side of the lid member. In the sections other than the wide welding trace section, the welding trace extends over the outer surface of the lid member and the opening end surface of the battery case main body and extends only locally on the outer surface of the battery case main body. In other words, the welding marks in the sections other than the wide welding mark section do not reach the outer surface of the battery case main body, or even if they extend, only locally. The second level, which is the level of welding energy in the section other than the wide welding mark section, is equal to or lower than the first level, and is preferably lower than the first level.

In the battery of the present invention, the center direction of the approximate sector shape applied to the arc-shaped portion of the cross-sectional shape of the weld trace is more outward in the wide weld trace section than in the sections other than the wide weld trace section. Tilt to the direction. In the battery of the present invention, when the welding mark is viewed from the outside,
The value obtained by dividing the penetration width on the battery case body side by the penetration width on the lid member side at the boundary between the outer surface of the lid member and the battery case body at the part that did not melt at the time of welding, Larger than sections other than the weld mark section. Alternatively, in the battery of the present invention, of the surface length in the cross-section of the weld mark, the boundary between the outer surface of the lid member and the battery case body at the portion not melted during welding extends from the line extending from the surface of the weld case to the battery case body side. The value obtained by dividing the surface length by the surface length on the lid member side is larger in the wide weld trace section than in the sections other than the wide weld trace section.

In the battery of the present invention, the external terminal member and the insulating member are provided at positions near both ends in the long side direction of the lid member, respectively, and the wide weld mark section is insulated on the one side with respect to the long side direction of the lid member. It is desirable to form over the section facing the member, the section facing the other insulating member, and the section between these sections. That is, in the battery manufacturing method of the present invention, the welding at the first level energy is performed in a section facing one insulating member and a section facing the other insulating member in the long side direction of the lid member. It is desirable to carry out over the section between these sections. This is more advantageous in terms of bonding strength between the lid member and the battery case body.

According to the present invention, there are provided a battery and a method for manufacturing the same which prevent the member on the lid member from being burned by the plume during welding.

It is sectional drawing which shows the battery which concerns on embodiment. It is an enlarged view of the B section and C section of FIG. It is a figure which shows the cover member with a terminal which concerns on embodiment. It is a perspective view of the electrode body which concerns on embodiment. It is a figure which shows the positive electrode plate which comprises the same electrode body. It is a figure which shows the negative electrode plate which comprises the same electrode body. It is a figure explaining the overlapping state of the positive / negative electrode plate etc. in the same electrode body. It is the top view which looked at the battery concerning an embodiment from the upper part. It is a part of top view which looked at the battery concerning an embodiment from the upper part at the time before welding. FIG. 10 is a cross-sectional view at a time point during and after welding of the X portion in FIG. 9. FIG. 10 is a cross-sectional view at a time point during and after welding of a Y portion in FIG. 9. It is sectional drawing in the time in the middle of welding of the Y location in a comparative example. FIG. 12 is a cross-sectional view for further explaining the melted portion shown in FIG. 11. FIG. 12 is a cross-sectional view for further explaining the melted portion shown in FIG. 11. It is sectional drawing which shows the condition of the welding location before welding in embodiment. It is sectional drawing which shows the condition of the welding location before welding in a comparative example. It is sectional drawing which shows the condition of the welding location before the welding in the modification of this invention. It is sectional drawing which shows the condition of the welding location before the welding in the modification of this invention. It is a top view which shows the whole battery case cover shape in the modification of this invention. It is a top view which shows the whole battery case cover shape in the modification of this invention.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a battery 100 according to the embodiment. FIG. 2 is an enlarged view of a portion B and a portion C in FIG. Note that FIG.
In the middle, the code without parentheses and the code with parentheses are written in two stages.
The members are different from each other. That is, the reference numerals without parentheses are for the B part member, and the reference numerals with parentheses are for the C part member. FIG. 3 is an exploded perspective view of a part of the lid member with terminal 115 according to the embodiment.

As shown in FIG. 1, the battery 100 according to this embodiment includes a lithium ion secondary battery that includes a rectangular box-shaped battery case body 111 having an opening 111 d and an electrode body 150 accommodated in the battery case body 111. It is a battery. Further, the battery 100 includes a plate-shaped battery case lid 113 that closes the opening 111 d of the battery case body 111. The battery case main body 111 and the battery case lid 113 are integrated by welding to constitute the battery case 110.

The battery case lid 113 has a rectangular plate shape, and circular through holes 113h, 11 penetrating the battery case lid 113 are disposed at positions near both ends in the long side direction (left and right direction in FIG. 1).
3k is formed. A safety valve 113j is provided at the longitudinal center of the battery case cover 113. The safety valve 113j is formed integrally with the battery case lid 113 and forms a part of the battery case lid 113.

The safety valve 113j is formed thinner than other portions of the battery case lid 113, and a groove 113jv is formed on the upper surface thereof (see FIG. 3). As a result, the safety valve 113j operates when the internal pressure inside the battery case 110 reaches a predetermined pressure. That is, when the internal pressure reaches a predetermined pressure, the groove 113jv breaks, and the gas inside the battery case 110 is released to the outside.

Further, a liquid injection port 113n for injecting an electrolyte (not shown) into the battery case 110 is formed between the safety valve 113j and the through hole 113k of the battery case lid 113 (FIG. 1).
reference). In the completed battery 100, the liquid injection port 113n is sealed with a liquid injection plug 113m.

Further, the battery 100 is connected to the electrode body 150 inside the battery case main body 111 and has a positive terminal member 130 and a negative terminal member 140 (outside terminal member) that extend to the outside through the through holes 113h and 113k of the battery case lid 113. ).

The positive electrode terminal member 130 includes a positive electrode connection member 135, a positive electrode external terminal member 137, and a positive electrode fastening bolt 139 (see FIGS. 1 and 3). Among these, the positive electrode connecting member 135 is connected to the electrode body 150 and extends to the outside through the through hole 113 h of the battery case lid 113. The positive external terminal member 137 is placed on the battery case lid 113, that is, the battery case 1.
10, and is electrically connected to the positive electrode connection member 135 outside the battery case 110. The positive fastening bolt 139 is mounted on the battery case lid 113, that is, the battery case 110.
The positive electrode external terminal member 137 is electrically connected to or connectable to the positive external terminal member 137. The positive electrode connecting member 135, the positive electrode external terminal member 137, and the positive electrode fastening bolt 139 are all made of aluminum.

Specifically, the positive electrode connection member 135 includes a pedestal part 131, an insertion part 132, and an electrode body connection part 134.
And a caulking portion 133 (see FIGS. 1 to 3). Of these, the pedestal 131 has a rectangular plate shape and is located inside the battery case main body 111. The insertion part 132 is a base part 13.
The cylindrical shape protrudes from the upper surface 131 f of the battery 1 and is inserted into the through hole 113 h of the battery case lid 113. The caulking portion 133 is a portion connected to the upper end of the insertion portion 132, is caulked, that is, deformed so as to expand in diameter, has a disk shape, and is electrically connected to the positive external terminal member 137. . The electrode body connecting portion 134 is joined to the positive electrode mixture layer non-coated portion 151b of the electrode body 150 in a form extending from the lower surface 131b of the pedestal portion 131 to the bottom surface 111b side of the battery case body 111. Thereby, the positive electrode connection member 135 and the electrode body 150 are electrically and mechanically connected.

The positive external terminal member 137 has a substantially Z shape in a side view. The positive external terminal member 137 includes a fixing portion 137f fixed by the crimping portion 133, a connecting portion 137g connected to the positive fastening bolt 139, and a connecting portion 13 connecting the fixing portion 137f and the connecting portion 137g.
7h. A through hole 137b is formed in the fixing portion 137f, and the insertion portion 132 of the positive electrode connection member 135 is inserted into the through hole 137b.
Further, the connecting portion 137g is also formed with a through hole 137c penetrating therethrough.

The positive fastening bolt 139 has a rectangular plate-shaped head portion 139b and a cylindrical shaft portion 139c. A portion on the tip side of the shaft portion 139c is a screw portion 139d. The shaft portion 139c of the positive electrode fastening bolt 139 is inserted into the through hole 137c of the positive electrode external terminal member 137.

The negative electrode terminal member 140 includes a negative electrode connection member 145, a negative electrode external terminal member 147, and a negative electrode fastening bolt 149 (see FIGS. 1 and 3). Among these, the negative electrode connection member 145 is connected to the electrode body 150 and extends to the outside through the through hole 113 k of the battery case lid 113. The negative external terminal member 147 is disposed on the battery case lid 113, that is, the battery case 1
10, and is electrically connected to the negative electrode connection member 145 outside the battery case 110. The negative fastening bolt 149 is mounted on the battery case lid 113, that is, the battery case 110.
And is electrically connected to or connectable to the negative external terminal member 147. The negative electrode connection member 145, the negative electrode external terminal member 147, and the negative electrode fastening bolt 149 are all made of copper.

Specifically, the negative electrode connection member 145 includes a pedestal part 141, an insertion part 142, and an electrode body connection part 144.
And a caulking portion 143 (see FIGS. 1 to 3). Of these, the pedestal portion 141 has a rectangular plate shape and is located inside the battery case body 111. The insertion part 142 is connected to the pedestal part 14.
A cylindrical shape protruding from the upper surface 141 f of the battery 1 is inserted into the through hole 113 k of the battery case lid 113. The caulking portion 143 is a portion connected to the upper end of the insertion portion 142, and is caulked, that is, deformed so as to expand in diameter, has a disk shape, and is electrically connected to the negative external terminal member 147. . The electrode body connecting portion 144 is joined to the negative electrode mixture layer non-coated portion 158b of the electrode body 150 in a form extending from the lower surface 141b of the pedestal portion 141 toward the bottom surface 111b of the battery case body 111. Thereby, the negative electrode connection member 145 and the electrode body 150 are electrically and mechanically connected.

The negative external terminal member 147 has a substantially Z shape in side view. This negative external terminal member 14
7 includes a fixing portion 147f fixed by the caulking portion 143, a connecting portion 147g connected to the negative fastening bolt 149, and a connecting portion 147h connecting the fixing portion 147f and the connecting portion 147g.
have. The fixing portion 147f is formed with a through hole 147b penetrating therethrough.
The insertion portion 142 of the negative electrode connection member 145 is inserted into the through hole 147b. Further, the connecting portion 147g is also formed with a through hole 147c penetrating therethrough.

The negative electrode fastening bolt 149 has a rectangular plate-shaped head portion 149b and a cylindrical shaft portion 149c. A portion on the tip side of the shaft portion 149c is a screw portion 149d. The shaft portion 149 c of the negative electrode fastening bolt 149 is inserted into the through hole 147 c of the negative electrode external terminal member 147.

Further, the battery 100 includes a first insulating member 170 that is interposed between the positive electrode terminal member 130 (specifically, the positive electrode connecting member 135) and the battery case lid 113 and electrically insulates both. The first insulating member 170 includes a negative electrode terminal member 140 (specifically, a negative electrode connection member 145).
And the battery case lid 113.

Specifically, the first insulating member 170 is made of an electrically insulating resin and has an insulating interposition part 171, an insulating side wall part 173, and an insertion part 175 (see FIGS. 2 and 3). Among these, the insulation interposition part 171 has a flat plate shape, and a positive electrode terminal member 130 (negative electrode terminal member 14) is formed at the center thereof.
0), a circular through-hole 175a through which the insertion part 132 (insertion part 142) is inserted.
This insulating interposition part 171 is a base part 131 (positive terminal member 130 (negative terminal member 140).
It is interposed between the upper surface 131 f (upper surface 141 f) of the base portion 141) and the battery case lid 113.

The insulating side wall part 173 is a square annular side wall part located on the periphery of the insulating interposition part 171. The insulating side wall portion 173 has an outer peripheral side surface 131g (the outer peripheral side surface 1) of the pedestal portion 131 (the pedestal portion 141).
41g). The insertion portion 175 has a cylindrical shape protruding from the upper surface 171f of the insulating interposition portion 171 and is inserted through the through hole 113h (through hole 113k) of the battery case lid 113. In the cylinder of the insertion portion 175, the insertion portion 132 (the negative terminal member 1) of the positive terminal member 130 is provided.
40 insertion parts 142) are inserted.

Further, the battery 100 includes a second insulating member 180 made of an electrically insulating resin and disposed on the battery case lid 113. The second insulating member 180 is connected to the positive terminal member 130 (
Specifically, the positive electrode external terminal member 137 and the positive electrode fastening bolt 139) are interposed between the battery case lid 113 and electrically insulate them. The second insulating member 180 is also interposed between the negative terminal member 140 (specifically, the negative external terminal member 147 and the negative fastening bolt 149) and the battery case lid 113.

Specifically, the second insulating member 180 includes a head arrangement portion 181 in which a head portion 139b of the positive electrode fastening bolt 139 (a head portion 149b of the negative electrode fastening bolt 149) is arranged, and the positive electrode external terminal member 13.
7 and a fastening arrangement part 183 in which a fixing part 137f (fixing part 147f of the negative electrode external terminal member 147) is arranged. The fastening arrangement portion 183 is formed with a through hole 183b penetrating therethrough, and the insertion portion 132 of the positive electrode terminal member 130 (the insertion portion 142 of the negative electrode terminal member 140) is inserted into the through hole 183b. Yes.

In the present embodiment, the battery case lid 113, the electrode terminal members (the positive terminal member 130 and the negative terminal member 140), the first insulating members 170 and 170, and the second insulating members 180 and 180 are used as a lid member with a terminal. 115 is configured. Specifically, the positive external terminal member 137, the second insulating member 180, the battery case lid 113, and the first insulating member 170 are sandwiched between the crimped portion 133 and the pedestal portion 131 of the positive electrode terminal member 130. While fixing, negative electrode terminal member 14
Between the 0 crimping portion 143 and the base portion 141, the negative external terminal member 147, the second insulating member 1
80, the battery case lid 113 and the first insulating member 170 are sandwiched and fixed to form a terminal-attached lid member 115 in which these are integrated.

In the lid member with terminal 115, the insulation interposed portion 171 of the first insulating member 170 is the upper surface 131f of the pedestal portion 131 (pedestal portion 141) of the positive electrode terminal member 130 (negative electrode terminal member 140).
It is sandwiched between (upper surface 141f) and the battery case lid 113, and is elastically compressed and arranged in its own thickness direction (vertical direction in FIG. 2). Furthermore, the insertion portion 175 of the first insulating member 170 is elastically compressed in its own axial direction (vertical direction in FIG. 2), and its tip 1
75b is in close contact with the second insulating member 180. In this manner, the through holes 113h and 113k of the battery case lid 113 are sealed by the first insulating member 170.

The electrode body 150 is a flat wound electrode body obtained by winding a belt-like positive electrode plate 155, a negative electrode plate 156, and a separator 157 into a flat shape (see FIGS. 4 to 7). As shown in FIG. 5, the positive electrode plate 155 has a belt-like shape extending in the longitudinal direction DA, and is disposed on a part of the surface of the positive electrode substrate 151 that is a current collector foil made of aluminum foil and the positive electrode substrate 151. And a positive electrode mixture layer 152. The positive electrode mixture layer 152 is made of a conductive material made of a positive electrode active material 153 and acetylene black, and PV.
DF (polyvinylidene fluoride, binder).

A portion of the positive electrode base material 151 where the positive electrode mixture layer 152 is coated is referred to as a positive electrode mixture layer coating portion 151c. On the other hand, a portion where the positive electrode mixture layer 152 is not coated is referred to as a positive electrode mixture layer non-coated portion 151b. The positive electrode mixture layer non-coated portion 151b is located at the end (left end in FIG. 5) of the positive electrode base 151 (positive plate 155) in the width direction DB (left and right in FIG. 5). Along the one long side of the positive electrode plate 155), it extends in the longitudinal direction DA of the positive electrode base material 151 (positive electrode plate 155), that is, in the vertical direction in FIG.

Further, as shown in FIG. 6, the negative electrode plate 156 is a belt-shaped member extending in the longitudinal direction DA, and a negative electrode base material 158 that is a current collector foil made of copper foil, and a part of the surface of the negative electrode base material 158. And a negative electrode mixture layer 159 arranged. The negative electrode mixture layer 159 includes a negative electrode active material 154, SBR (styrene-butadiene rubber, binder), and CMC (carboxymethyl cellulose, thickener).

A portion of the negative electrode base material 158 where the negative electrode mixture layer 159 is coated is referred to as a negative electrode mixture layer coating portion 158c. On the other hand, a portion of the negative electrode base material 158 where the negative electrode mixture layer 159 is not coated is referred to as a negative electrode mixture layer non-coated portion 158b. The negative electrode mixture layer non-coated portion 158b is formed of the negative electrode base material 1
58 (negative electrode plate 156) is located at the end portion (right end portion in FIG. 6) in the width direction DB (left and right direction in FIG. 6), and extends along one long side of the negative electrode base material 158 (negative electrode plate 156). Material 158 (
The negative electrode plate 156) extends in the longitudinal direction DA, that is, in the vertical direction in FIG.

As shown in FIG. 7, the electrode body 150 of FIG. That is, in the superposition of FIG. 7, the positive electrode plate 155, the negative electrode plate 156, and the two separators 157 are superposed, and the positive electrode mixture layer non-coated portion 151b and the negative electrode mixture layer non-coated portion 158 are overlapped.
b protrudes in the opposite direction. The width of the separator 157 is substantially the same as the width of the positive electrode mixture layer coating portion 151c and the negative electrode mixture layer coating portion 158c. Therefore, in FIG. 4 showing the wound state, the positive electrode mixture layer non-coated portion 151b is a stack of a plurality of positive electrode base materials 151, and the negative electrode mixture layer non-coated portion 158b is a plurality of sheets. The negative electrode base material 158 is superposed.

In the battery 100 configured as described above, the characteristic feature of the present invention resides in the welded portion between the battery case body 111 and the battery case lid 113. As shown in the plan view of FIG.
Then, the boundary between the battery case body 111 and the battery case lid 113 is welded over the entire circumference,
A welding mark 160 is formed.

Before describing the details of the weld mark 160, the distance between the second insulating member 180 of the terminal portion and the edge of the battery case lid 113 will be described. As shown in the partial plan view of FIG.
In 00, the distance between the second insulating member 180 and the edge of the battery case lid 113 is different in the long side direction and the short side direction. That is, the long side 11 of the second insulating member 180 and the battery case lid 113 is used.
The distance Ga between the second insulating member 180 and the short side 113b of the battery case lid 113 is smaller than the distance Gb between the second insulating member 180 and the battery case cover 113. This is because the overall shape of the battery 100 is flat and the battery case lid 113 is rectangular. FIG. 9 is a plan view of the battery case cover 113 (terminal cover member 115) fitted into the battery case body 111 and before welding. Also,
Although not shown, the same applies to the negative electrode side near the right end.

Returning to the plan view after welding in FIG. 8, it can be seen that the width of the welding mark (the portion melted during welding) 160 is different between the long side 113 a and the short side 113 b of the battery case lid 113. . The welding mark 160 is wide at the long side 113a, whereas the welding mark 160 is narrow at the short side 113b. This will be further described with reference to a sectional view.
FIG. 10 shows a cross-sectional view of the portion X in FIG. 9, and FIG. 11 shows a cross-sectional view of the portion Y. From these sectional views, it can be seen that the battery case lid 113 is thicker than the battery case body 111.

First, looking at FIG. 10 on the short side, the welding trace 160 straddles the upper surface 113e of the battery case lid 113 and the opening end surface 111e of the battery case main body 111, but on the outer side surface 111s of the battery case main body 111. It does not reach. On the other hand, in FIG.
The upper surface 113e of the battery case extends to the outer surface 111s of the battery case body 111. This difference between the short side and the long side appears as the width of the weld mark 160 in FIG.

The difference between FIG. 10 and FIG. 11 will be further described. When welding the short side as shown in FIG. 10, the melting during welding is caused by the upper surface 113 e of the battery case lid 113 and the battery case body 111.
The welding energy is set to be relatively small so as not to reach the outer end surface 111s of the battery case body 111 but only to the opening end surface 111e. In FIG. 10, at this time, the battery case lid 113 and the battery case main body 111 are melted almost uniformly. For this reason, the approximate sector T of the melted portion is almost vertical. For this reason, the plume P is ejected in the direction of the arrow Q that is the central direction of the approximate sector T, that is, vertically upward. Nevertheless, since the gap Gb is large, the second insulating member 18
0 is not burned by the plume P. The approximate sector T is a sector configured by a portion of the surface shape of the weld mark 160 in the cross section that can be approximated by an arc and radii with respect to both ends of the arc.

On the other hand, when the long side portion is welded as shown in FIG. 11, the welding energy is increased as compared with the case where the short side portion is welded. Then, compared with FIG. 10, the melting range becomes wider. Further, the penetration depth Ma is also larger than the penetration depth Mb in FIG. However, the battery case cover 113
The melting range does not spread evenly on the side and the battery case body 111 side. The melting range widens more on the battery case body 111 side and does not spread much on the battery case lid 113 side.

The reason is the difference in plate thickness between the battery case body 111 and the battery case lid 113. Due to the difference in heat capacity due to the difference in plate thickness, more heat escapes on the battery case lid 113 side than on the battery case body 111 side. For this reason, since the temperature rise is more intense on the battery case lid 113 side, the melting range is greatly expanded on the battery case body 111 side. For this reason, in FIG. 11, the approximate sector T of the melted portion and the center direction R thereof are inclined outward. For this reason, the plume P is also emitted inclining outward. Therefore, even if the gap Ga is small, the second insulating member 180 is not burned by the plume P.

If the long side is welded with low welding energy as in the description of FIG.
Although a is small, the plume P is ejected almost vertically from the edge (long side) of the battery case lid 113. That is, the plume P exists in the immediate vicinity of the second insulating member 180, and the second insulating member 180 may be burned. In particular, if the plume P sways due to a surrounding air current or the like, the plume P easily hits the second insulating member 180 as shown in FIG. On the other hand, in this embodiment, the above-mentioned adverse effects are prevented by welding the long side portion with large energy. The welding method is laser welding, etc.
Any method can be used as long as it can be welded to the welding portion in a non-contact manner.

The following can be said about the welding mark 160 of the long side portion shown in FIG. As shown in FIG. 13, with respect to the extension line S at the boundary between the battery case body 111 and the battery case lid 113 in the unmelted portion, the penetration width W into the battery case body 111 when viewed from above.
a and the penetration width Wb to the battery case lid 113 side can be considered. At this time, the penetration width Wa is larger than the penetration width Wb. That is, “Wa / Wb” is larger than 1. In consideration of such a thing with the welding mark 160 of the short side part of FIG. 10, “Wa / Wb” is almost 1
become. Therefore, the welding mark 160 on the long side portion is compared with the welding mark 160 on the short side portion,
It can be said that the value of “Wa / Wb” is large. Also, the value of Wa itself is larger at the long side than at the short side.

Further, as shown in FIG. 14, the surface length La on the battery case body 111 side and the surface length Lb on the battery case lid 113 side of the welding mark 160 can be considered with respect to the extension line S on the cross-sectional view. . Also in this case, the surface length La is larger than the surface length Lb. And it can be said that the value of “La / Lb” is larger in the welding mark 160 in the long side portion than in the welding mark 160 in the short side portion. Also, the value of La itself is larger at the long side than at the short side.

In the present invention, as shown in FIG. 15, the battery case main body 111 is inserted at a time point after the battery case cover 113 (lid member 115 with terminal) is fitted into the battery case main body 111 and before the welding is performed.
The open end surface 111e is not covered by the battery case lid 113. In such a case, the plume P at the time of welding is the upper surface side of the battery case lid 113, that is, the second insulating member 1.
It is because it spouts to the side with 80.

On the other hand, as shown in FIG. 16, the case where the opening end surface 111e is covered with the battery case lid 113 before welding is not an object of the present invention. This is because it is impossible that the plume P at the time of welding reaches the second insulating member 180 in such a case. On the other hand, as shown in FIG. 17, the opening end surface 111e is exposed without being covered by the battery case cover 113, and thus can be applied to the present invention. In addition, the upper surface 113e of the battery case lid 113
Even if shapes other than those described above (for example, the groove 113f in FIG. 18) are further formed, application of the present invention is not hindered. 13 to 18, the second in FIG.
The insulating member 180 and the like are omitted.

In the present invention, the wide welding mark 160 shown in FIG.
13 must be provided in a region facing the second insulating member 180 in the vicinity of both ends of 13. That is, it is the section Z1, Z3 in FIG. For the section Z2 between them, the wide welding marks 160 of the sections Z1 and Z3 may be formed, or the narrow welding marks 16 in FIG.
0 may be formed. However, it is advantageous in terms of joint strength to form a wide welding mark 160 in the section Z2. Furthermore, the wide welding mark 160 of FIG. 11 may be formed over the entire circumference of the battery case lid 113. Further, in the actual product, even in the section where the narrow welding mark 160 of FIG. 10 is formed by welding with low energy, the welding mark 160 locally reaches the outer surface 111s of the battery case body 111 in some places. Is possible.

Furthermore, the planar shape of the battery case lid 113 has been described as a rectangular plate, but the corner may be round as shown in FIG. In short, it is only necessary to recognize the long side portion and the short side portion. Further, the short side portion may have a shape without a straight portion as shown in FIGS. 19 and 20.

As described above in detail, according to the present embodiment, the battery 100 has a flat shape, and the open end surface 111e of the battery case main body 111 is not covered with the battery case lid 113 before the welding. The welding energy is changed between the short side portion and the long side portion of the case lid 113, and the welding energy at the long side portion is increased from the short side portion. As a result, when welding the long side facing the second insulating member 180, the battery case body 111 side is more melted and the plume P is inclined outward and ejected. In this way, the battery 10 prevents the second insulating member 180 and the like on the battery case lid 113 from being damaged by the plume P during welding.
0 and its manufacturing method are realized.

Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.

111 Battery Case Body 111e Open End Surface 113 of Battery Case Body Battery Case Cover (Cover Member)
113e Upper surface 130,140 of battery case lid Terminal member (outside terminal member)
150 Electrode body 160 Weld mark 180 Second insulating member (insulating member)
Ga, Gb Spacing La, Lb Surface length Q, R of welding trace Central direction T Approximate sector Wa, Wb Penetration width Z1, Z3 Section Z2 facing section of insulation member Z1, section Z3

Claims (7)

In a battery having a flat battery case body having a built-in power generation element and having one side opened, and a lid member that has a long side portion and a short side portion and closes the opening portion of the battery case body,
An external terminal member provided through the lid member, which is connected to the power generation element in the battery case body and partially exposed to the outside;
An insulating member that is disposed at least on the outer surface side of the lid member and insulates the external terminal member from the lid member;
An interval between the edge of the insulating member and the long side of the lid member is smaller than an interval between the edge of the insulating member and the short side of the lid member;
The lid member is fitted into the opening of the battery case body,
A welding mark straddling the outer surface of the lid member and the opening end surface of the battery case body is formed over the entire circumference of the lid member, so that the lid member is fixed to the battery case body and the battery case body The inside is sealed from the outside world,
Of the long side of the lid member, at least the section facing the insulating member has the weld mark,
A battery having a wide welding mark section formed not only on an outer surface of the lid member and an opening end surface of the battery case body but also on an outer surface of the battery case body. The battery according to claim 1,
The center direction of the approximate sector shape applied to the arc-shaped portion of the cross-sectional shape of the weld trace is inclined more outward in the wide weld trace section than in the sections other than the wide weld trace section. A battery characterized by having The battery according to claim 1,
When the welding mark is viewed from the outside, a penetration width to the battery case body side with respect to a boundary between the outer surface of the lid member and the battery case body at a portion not melted at the time of welding to the lid member side. A battery characterized in that a value obtained by dividing by a penetration width is larger in the wide welding trace section than in a section other than the wide welding trace section. The battery according to claim 1,
Of the surface length in the cross section of the welding mark, the surface on the battery case main body side from the line extending from the outer surface of the lid member to the battery case main body at the portion not melted during welding to the surface of the welding mark The value obtained by dividing the length by the surface length on the lid member side is the wide weld mark section.
Batteries characterized in that they are larger than sections other than the wide welding mark section. In the battery according to any one of claims 1 to 4,
The external terminal member and the insulating member are respectively provided at positions near both ends in the long side direction of the lid member;
The wide welding mark section is formed across a section facing the one insulating member, a section facing the other insulating member, and a section between these sections in the long side direction of the lid member. A battery characterized by comprising: In a battery manufacturing method comprising a flat battery case body having a built-in power generation element and one of which is open, and a lid member that has a long side portion and a short side portion and closes the opening portion of the battery case body ,
The target battery is
Connected to the power generation element in the battery case body and partially exposed to the outside,
An external terminal member provided through the lid member;
An insulating member that is disposed at least on the outer surface side of the lid member and insulates the external terminal member from the lid member;
The distance between the edge of the insulating member and the long side of the lid member is smaller than the distance between the edge of the insulating member and the short side of the lid member;
The lid member is in a state of being fitted into the opening of the battery case body without covering the opening end surface of the battery case body,
By welding the boundary between the outer surface of the lid member and the opening end surface of the battery case body over the entire circumference of the lid member, the lid member is fixed to the battery case body and the inside of the battery case body is externally exposed. Sealed,
The energy in the welding is
In at least a section facing the insulating member on the long side of the lid member, a welding mark is formed not only on the outer surface of the lid member and the opening end surface of the battery case body but also on the outer surface of the battery case body. The first level energy to be
The battery manufacturing method according to claim 1, wherein a second level energy equal to or lower than the first level is used in a section other than a section where welding with the first level energy is performed. In the manufacturing method of the battery according to claim 6,
The target battery is such that the external terminal member and the insulating member are provided at positions near both ends in the long side direction of the lid member,
Welding at the first level of energy with respect to the long side direction of the lid member, a section facing one of the insulating members, a section facing the other insulating member, and a section between the sections; A method for producing a battery, characterized by comprising:

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