JP7319952B2 - SECONDARY BATTERY AND METHOD FOR MANUFACTURING SECONDARY BATTERY - Google Patents

Description

The present invention relates to a secondary battery and a method for manufacturing a secondary battery.

Currently, secondary batteries such as lithium-ion batteries and nickel-metal hydride batteries are used in vehicles such as hybrid vehicles, plug-in hybrid vehicles, and electric vehicles that use electric power as driving force. A secondary battery has an external terminal and is connected to an adjacent secondary battery via a bus bar welded to the external terminal.

As an example of such a secondary battery, Patent Document 1 discloses a secondary battery in which a conductive member is connected to an external terminal and a bus bar is welded to the conductive member.

WO2018/056345

However, in the secondary battery disclosed in Patent Document 1, since the conductive member is folded, the heat of welding the bus bar to the conductive member is easily transmitted to the external terminals. Usually, a sealing member made of resin or the like is arranged around the external terminals. Therefore, in the secondary battery disclosed in Patent Literature 1, the welding heat of the busbar may deteriorate the sealing member, shortening the life of the sealing member.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and provides a secondary battery having an external terminal capable of reducing the influence of welding heat on a busbar, and a method for manufacturing the secondary battery. for the purpose.

A secondary battery according to an exemplary embodiment of the present invention includes a current collecting terminal and an external terminal connected to the current collecting terminal using a connection part,
The external terminal is formed of a metal plate having a folded portion,
A gap is formed between one side and the other side of the external terminal bounded by the folded portion.
A bus bar is welded to the other side.

The other side is positioned higher than the one side and can extend from the folded portion to above the connection portion.

Furthermore, a concave portion may be formed on at least one surface of the folded portion.

Further, the metal plate is a clad material having a first metal containing a metal forming the collector terminal and the connecting portion and a second metal containing a metal forming the bus bar. The connection can be welded to a first metal portion contained on one side and the busbar can be welded to a second metal portion contained on the other side.

Further, the cladding material can be an overlay cladding material having a first layer formed of a first metal and a second layer formed of a second metal, the connection portion being included on one side. can be welded to the first layer contained on the other side and the busbar can be welded to the second layer contained on the other side.

Furthermore, the collector terminal and the connecting portion can be integrally formed.

A method for manufacturing a secondary battery comprising a current collecting terminal according to an exemplary embodiment of the present invention and an external terminal connected to the current collecting terminal using a connecting portion comprises:
including a bending step of bending the metal plate to form the folded portion of the external terminal;
In the bending step, the metal plate is bent such that a gap is formed between one side of the external terminal bounded by the bent portion and the other side to which the bus bar is welded.

Also, in the bending step, the metal plate can be bent such that the other side extends above the connecting portion welded to the one side.

Furthermore, the method for manufacturing a secondary battery can further include the step of forming a recess in at least one surface of the metal plate to be the folded portion before performing the folding step.

ADVANTAGE OF THE INVENTION By this invention, the manufacturing method of the secondary battery provided with the external terminal which can reduce the influence by welding heat of a bus-bar, and a secondary battery can be provided.

1 is a perspective view showing a secondary battery according to a first embodiment of the invention; FIG. 1 is an enlarged view of a secondary battery according to a first embodiment of the invention; FIG. FIG. 2 is a cross-sectional view along the II cross-sectional line of FIG. 1; FIG. 4 is a cross-sectional view of a negative electrode side of a secondary battery according to a second embodiment of the present invention; It is a figure which shows the side surface of the negative external terminal which concerns on the 3rd Embodiment of this invention.

<First embodiment>
Exemplary embodiments of the invention will now be described with reference to the drawings. FIG. 1 is a perspective view showing secondary batteries 1, 2 and 3 according to the first embodiment of the present invention. Secondary battery 1 is arranged so as to be adjacent to secondary batteries 2 and 3 . Secondary batteries 1, 2 and 3 are provided with negative external terminals 100a, 200a and 300a and positive external terminals 100b, 200b and 300b, respectively, at the top. A negative external terminal 100 a of the secondary battery 1 is connected to a positive external terminal 200 b of the secondary battery 2 via the busbar 30 . A positive external terminal 100 b of the secondary battery 1 is connected to a negative external terminal 300 a of the secondary battery 3 via a busbar 31 .

FIG. 2 is an enlarged view of the secondary battery 1 according to the first embodiment of the invention. The secondary battery 1 includes a case 120 , a lid 130 , and a negative external terminal 100 a and a positive external terminal 100 b connected to the lid 130 . In the secondary battery 1, a lid 130 to which a negative external terminal 100a and a positive external terminal 100b are connected is placed on top of a case 120, and the lid 130 and the case 120 are welded together.

The negative electrode external terminal 100a is connected to a negative collector terminal (not shown) by inserting the negative electrode connection portion 110a into the through hole and crimping it. Similarly, the positive electrode external terminal 100b is connected to a positive collector terminal (not shown) by inserting the positive electrode connecting portion 110b into the through hole and crimping it. In the present embodiment, the negative electrode connecting portion 110a and the positive electrode connecting portion 110b are formed integrally with the negative current collecting terminal and the positive current collecting terminal, respectively. The negative collector terminal and the positive collector terminal are respectively connected to a negative electrode body and a positive electrode body (not shown) inside the case 120 .

The negative electrode external terminal 100a and the positive electrode external terminal 100b are made of metal plates and have folded portions 11a and 11b, respectively. A gap G is formed between one side 12a, 12b and the other side 13a, 13b of the negative electrode external terminal 100a and the positive electrode external terminal 100b, respectively, bounded by the folded portions 11a, 11b.

The negative external terminal 100a is made of a clad material containing a first metal and a second metal. The first metal is formed including a metal (such as copper) that forms the negative collector terminal and the negative electrode connecting portion 110a. The second metal is formed including the metal (aluminum or the like) that forms busbars 30 and 31 .

FIG. 3 is a cross-sectional view along the II cross-sectional line of FIG. Note that the negative electrode current collecting terminal is omitted in FIG. 3 to simplify the explanation.

In this embodiment, an overlay clad material is used as the clad material forming the negative electrode external terminal 100a. As shown in FIG. 3, the overlay clad material forming the negative external terminal 100a has a first layer 14 made of a first metal and a second layer 15 made of a second metal. The negative electrode connecting portion 110a is welded to the first layer 14 included in one side 12a of the negative electrode external terminal 100a. The bus bar 30 is welded to the second layer 15 included on the other side 13a of the negative external terminal 100a. In the secondary battery 1, a sealing member 140 for sealing the secondary battery 1 is arranged around the negative electrode connecting portion 110a. Similarly, a sealing member 140 is also arranged around the positive electrode connection portion 110b connected to the positive electrode external terminal 100b.

The positive external terminal 100 b is formed of a metal plate containing the second metal forming the bus bar 31 . As shown in FIG. 2, on the positive electrode side, the positive electrode connection portion 110b is welded to one side 12b of the positive electrode external terminal 100b. Also, the bus bar 31 is welded to the other side 13b of the positive external terminal 100b.

The manufacturing method of the secondary battery according to the first embodiment of the present invention includes a bending step of bending a metal plate to form folded portions 11a and 11b of the negative electrode external terminal 100a and the positive electrode external terminal 100b. In the bending step, the metal plate is bent such that a gap G is formed between one side 12a, 12b and the other side 13a, 13b bounded by the bent portions 11a, 11b.

As described above, in the first embodiment, the negative external terminal 100a and the positive external terminal 100b are formed of metal plates having folded portions 11a and 11b. A gap G is formed between one side 12a, 12b and the other side 13a, 13b bounded by the folded portions 11a, 11b. Bus bars 30 and 31 are welded to the other sides 13a and 13b, respectively.

As a result, the heat for welding the busbars 30 and 31 to the negative external terminal 100a and the positive external terminal 100b is less likely to be transferred to other members in contact therewith, such as the negative electrode connection portion 110a and the positive electrode connection portion 110b. Therefore, it is possible to suppress deterioration of the seal member 140 arranged around the negative electrode connection portion 110 a and the positive electrode connection portion 110 b due to the welding heat of the bus bars 30 and 31 .

Moreover, since the negative electrode external terminal 100a and the positive electrode external terminal 100b have the folded portions 11a and 11b, the other sides 13a and 13b can move up and down. Therefore, it is possible to absorb variations in the height dimension of the secondary batteries 1, 2, 3 arranged adjacent to each other, and to reliably weld the bus bars 30, 31 to the external terminals of these secondary batteries. can. Furthermore, the vertical movement of the other sides 13a, 13b can absorb external impacts, and damage to the constituent parts of the secondary batteries 1, 2, 3 can be reduced.

Furthermore, since the negative electrode external terminal 100a and the positive electrode external terminal 100b have the folded portions 11a, 11b and the other side 13a, 13b, when the lid 130 is arranged on the upper portion of the case 120, the jig is placed between the folded portions 11a, 11b and The other side 13a, 13b can be gripped. When using a jig to grip these portions, it is necessary to arrange the jig below the portion to be gripped. As described above, since the gap G is provided between the one side 12a, 12b and the other side 13a, 13b, the jig does not interfere with the lid 130 immediately below the negative electrode external terminal 100a and the positive electrode external terminal 100b. The folded portions 11a and 11b and the other sides 13a and 13b can be gripped without the grip. Therefore, when attaching the lid 130 to the case 120, there is no need for a jig to grip the side surface of the lid 130, which prevents the side surface of the lid 130 from being damaged and the side surface from being stained. It is possible to perform reliable can sealing welding. In addition, it is preferable that the gap G is equal to or larger than the thickness of the gripped other sides 13a and 13b. Specifically, it is 1 mm or more, more preferably 1.5 mm or more.

Further, the negative electrode external terminal 100a is formed using an overlay clad material having a first layer 14 made of a first metal and a second layer 15 made of a second metal. The negative electrode connecting portion 110a is welded to the first layer 14 included in one side 12a of the negative electrode external terminal 100a. The bus bar 30 is welded to the second layer 15 included on the other side 13a of the negative external terminal 100a.

Since the negative electrode connecting portion 110a and the one side 12a of the negative electrode external terminal 100a are made of the first metal, the negative electrode connecting portion 110a can be welded to the one side 12a made of the same material as the negative electrode connecting portion 110a. This enables good welding between the negative electrode connection portion 110a and the negative electrode external terminal 100a.

In addition, since the bus bar 30 and the other side 13a of the negative external terminal 100a are made of the second metal, the bus bar 30 can be welded to the other side 13a of the same material as the bus bar 30 . This enables good welding between the bus bar 30 and the negative electrode external terminal 100a.

<Second embodiment>
FIG. 4 is a cross-sectional view showing a cross section of the negative electrode side of the secondary battery 1 according to the second embodiment of the invention. In the second embodiment, as shown in FIG. 4, the other side 13a positioned above the one side 12a of the negative electrode external terminal 100a extends from the folded portion 11a to above the negative electrode connecting portion 110a. Similarly, on the positive electrode side, the other side 13b positioned above the one side 12b of the positive electrode external terminal 100b extends from the folded portion 11b to above the positive electrode connecting portion 110b.

In the bending step according to the second embodiment, the other side 13a of the negative electrode external terminal 100a and the other side 13b of the positive electrode external terminal 100b extend above the negative electrode connection portion 110a and the positive electrode connection portion 110b, respectively. A metal plate is bent. The bending step is performed after connecting the negative electrode external terminal 100a and the positive electrode external terminal 100b to the negative electrode connection portion 110a and the positive electrode connection portion 110b, respectively.

As described above, in the second embodiment, the other side 13a of the negative electrode external terminal 100a and the other side 13b of the positive electrode external terminal 100b extend from the folded portions 11a and 11b to above the negative electrode connection portion 110a and the positive electrode connection portion 110b, respectively. exist. Therefore, the busbars 30 and 31 can be arranged above the negative electrode connection portion 110a and the positive electrode connection portion 110b, and space saving of the secondary batteries 1, 2, and 3 can be realized.

<Third Embodiment>
FIG. 5 is a side view of the negative external terminal 100a according to the third embodiment of the present invention. In the third embodiment, as shown in FIG. 5, concave portions 16 and 17 are formed on both surfaces of the folded portion 11a of the negative electrode external terminal 100a. In another embodiment, a concave portion may be formed on one surface of the folded portion 11a. Similarly, in the folded portion 11b of the positive electrode external terminal 100b, a concave portion can be formed on at least one surface of the folded portion 11b.

The method for manufacturing a secondary battery according to the third embodiment further includes the step of forming recesses in at least one surface of the metal plate that will become the folded portions 11a and 11b before performing the step of bending the metal plate. . By forming recesses in at least one surface of the metal plate, which will be the folded portions 11a and 11b of the negative electrode external terminal 100a and the positive electrode external terminal 100b, the metal plate can be easily bent.

<Other embodiments>
In another embodiment, the negative external terminal 100a may be formed using an inlay clad material having a first metal (such as copper) and a second metal (such as aluminum). When the negative electrode external terminal 100a is formed using the inlay clad material, the negative electrode connection portion 110a formed of the first metal is welded to the first metal portion included in the one side 12a of the negative electrode external terminal 100a. . A bus bar 30 made of a second metal is welded to the second metal portion included on the other side 13a.

In another embodiment, the positive electrode external terminal 100b may be formed using a clad material in which aluminum is used as the first metal and copper is used as the second metal. In this case, the positive electrode connection portion 110b made of the first metal (aluminum) is welded to the first metal portion on the one side 12b of the positive electrode external terminal 100b. A bus bar 31 made of a second metal (copper) is welded to the second metal portion on the other side 13b of the positive external terminal 100b. The negative external terminal 100a is made of a second metal (copper). A negative electrode connection portion 110a made of a second metal is welded to one side 12a of the negative electrode external terminal 100a. A bus bar 30 made of a second metal is welded to the other side 13a of the negative external terminal 100a.

Furthermore, in another embodiment, the positive electrode external terminal 100b may be formed using an inlay clad material having a first metal (such as aluminum) and a second metal (such as copper). When the positive electrode external terminal 100b is formed using the inlay cladding material, the positive electrode connection portion 110b formed of the first metal (aluminum) is located at the first metal portion included in the one side 12b of the positive electrode external terminal 100b. Welded. A bus bar 31 made of a second metal (copper) is welded to the second metal portion included in the other side 13b.

Furthermore, in other embodiments, the negative current collector terminal and the negative electrode connecting portion 110a may be configured as separate components. Also, the positive current collector terminal and the positive electrode connecting portion 110b may be configured as individual components.

The present invention is not limited to the above-described embodiments, and can be modified as appropriate without departing from the gist of the present invention.

1, 2, 3 Secondary battery 100a Negative external terminal 200a Negative external terminal 300a Negative external terminal 100b Positive external terminal 200b Positive external terminal 300b Positive external terminals 11a, 11b Folded portions 12a, 12b One side 13a, 13b Other side 14 First Layer 15 Second layers 16, 17 Recess 110a Negative electrode connecting portion 110b Positive electrode connecting portion 120 Case 130 Lid 140 Seal members 30, 31 Busbar G Gap

Claims (9)

A secondary battery comprising a collector terminal and an external terminal connected to the collector terminal via a connecting portion,
The external terminal is formed of a metal plate having a folded portion,
A gap is formed between one side and the other side of the external terminal bounded by the folded portion,
The cross-sectional shape of the external terminal is J-shaped,
The one side has a through hole and is connected to the connecting portion inserted into the through hole,
The other side is shorter than the one side and extends from the folded portion to the front of the connecting portion,
A secondary battery, wherein a bus bar is welded to the other side. 2. The secondary battery according to claim 1 , wherein a sealing member is arranged around said connecting portion . 3. The secondary battery according to claim 1, wherein said folded portion has a concave portion formed on at least one surface thereof. The metal plate is a clad material having a first metal containing a metal forming the collector terminal and the connecting portion and a second metal containing a metal forming the bus bar. and
the connecting portion is welded to the portion of the first metal included on the one side;
4. The secondary battery according to claim 1, wherein said bus bar is welded to said second metal portion included in said other side. The clad material is an overlay clad material having a first layer made of the first metal and a second layer made of the second metal,
the connecting portion is welded to the first layer included on the one side;
5. The secondary battery according to claim 4, wherein said bus bar is welded to said second layer included in said other side. The secondary battery according to any one of claims 1 to 5, wherein the collector terminal and the connection portion are integrally formed. A method for manufacturing a secondary battery comprising a collector terminal and an external terminal connected to the collector terminal via a connection part,
a bending step of bending a metal plate to form the external terminal having a folded portion ;
an arranging step of arranging the external terminals,
In the bending step, a gap is formed between one side of the external terminal bounded by the folded portion and the other side to which the bus bar is welded , so that the external terminal has a J-shaped cross section. so that the metal plate is bent ,
The arranging step includes
arranging the external terminal such that the other side, which is shorter than the one side, extends from the folded portion to the front of the connecting portion;
A step of inserting the connection part into a through hole provided on the one side to connect the one side and the connection part,
A method for manufacturing a secondary battery. 8. The method of manufacturing a secondary battery according to claim 7 , further comprising the step of arranging a sealing member around said connecting portion . The method for manufacturing the secondary battery includes:
9. The method of manufacturing a secondary battery according to claim 7, further comprising the step of forming a concave portion in at least one surface of said metal plate to be said folded portion before performing said bending step.

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