JP2003303582A - Enclosed battery and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an enclosed battery of high reliability, having high joining strength between a conductive connection tab joined to a battery element and a connection terminal of a battery header or a metallic plate of the battery header. <P>SOLUTION: This enclosed battery 1 is manufactured by accommodating the battery element 3 from an opening part of a battery can, then one side of the conductive connection tab 4 connected to the battery element 3 is connected to an electrode connection terminal 6 formed by mounting an insulating member 10 on the battery header 5 closing the opening part of the battery can, and the other side of the conductive connection tab 7 is joined to an inner wall face of the battery can. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed battery, which is characterized by a connection between a conductive connection tab joined to a battery element and an external connection terminal provided on the inner surface of a battery can. .

[0002]

2. Description of the Related Art Portable electronic devices are becoming smaller and lighter and more sophisticated. As a result, batteries for power supplies used in these electronic devices are required to be small, lightweight, and have a large capacity per volume. Lithium ion batteries that use positive electrode active material and negative electrode active material that are doped and dedoped with lithium ions are secondary batteries that have a large energy density per volume or mass compared to conventional nickel cadmium batteries and lead batteries. It is used as a battery and as a power source for small electronic devices.

A lithium ion battery is provided in a battery element after a battery element manufactured by winding a positive electrode and a negative electrode with a separator interposed therebetween, or a battery element in which a positive electrode and a negative electrode are laminated is housed in a metal can. Join the conductive connection tab of one polarity to the electrode terminal in which the electrode having a polarity different from that of the battery can is insulated with an insulating member, and the tab for conductive connection of the other polarity is welded to the wall or lid of the battery can. After mounting, a lid is fitted in the opening of the battery can and sealed.

FIG. 6 is a diagram for explaining a conventional sealed battery. As shown in FIG. 6A, in the sealed battery 1, the battery element 3 is stored in the battery can 2 after the battery element 3 is housed in the opening of the battery can 2.
Resistance welding for applying a welding current to the electrode connection terminal 6 provided on the metal plate 8 of the battery header 5 that seals the opening of the battery can via the insulating member.
Alternatively, after joining by laser welding and joining the other conductive connection tab 7 to the inner wall surface of the battery can, as shown in FIG.
After the conductive connection tab is deformed as shown in (B), the battery header is attached to the opening of the battery can 2, and the battery header 5 is attached to the opening of the battery can 2 as shown in FIG. 6 (C). After fitting, the joining portion between the battery can and the battery header is joined by a method such as laser welding, and the liquid injection port 9 is removed and sealed.
The sealed battery 1 is manufactured by injecting the electrolytic solution and sealing the injection port. In the case of a battery electrode coated with an electrode active material using a strip-shaped metal foil as a current collector, such as a lithium-ion battery, the conductive connection tab to be joined to the battery electrode is thin, so the welding current is small and formed. The nugget is small,
The strength of the joint was also small.

Therefore, it is possible to use a thick conductive connecting tab, but when the thick conductive connecting tab is joined to the battery electrode constituting the battery element, the conductive connecting tab partially reduces the thickness of the battery element. In addition, as the thickness of the conductive connection tab becomes thicker, more space is required for connecting the conductive connection tab inside the battery, and the thickness of the conductive connection tab is required to reduce the battery size. Was required to be thin. There is also a method of joining the conductive connection tabs by caulking instead of welding, but caulking does not provide sufficient electrical connection. It has been difficult to realize a low-impedance battery with little change over time.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a hermetically sealed battery having a large bonding strength between a conductive connection tab bonded to a battery element in a sealed battery and a connection terminal of the battery header, or a metal plate of the battery header, and having high reliability. It is an object to provide a type battery.

[0007]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide, in a sealed battery, a conductive connection tab joined to a battery element and a conductive connection portion inside the battery, and the conductive connection tab is the same as the conductive connection portion. It is a sealed battery covered with a joining auxiliary tab joined to a polar part of and welded to a conductive connecting portion. A joining auxiliary tab is joined to the conductive connecting portion, the conductive connecting tab is located on the side opposite to the joining surface of the joining auxiliary tab with the conductive connecting portion, and the bent portion of the joining auxiliary tab covers the conductive connecting tab. It is a sealed battery that is welded to the conductive connection part. The conductive connection tab, which is in contact with the conductive connection portion, is a sealed battery that is welded to the conductive connection portion by being covered with a bonding auxiliary tab that is bonded to a portion having the same polarity as the conductive connection portion, and is a battery. It is a sealed battery that is a wall surface of a can, a metal plate of a battery header, or a connection portion formed on them through an insulating member. The conductive connection tab of one polarity was joined to the conductive connection portion provided on the metal plate of the battery header, and the other conductive connection tab was joined to the conductive connection terminal provided on the metal plate of the battery header via the insulating member. It is a sealed battery. The sealed battery according to claim 1, wherein the conductive connection tab has a thickness of 0.1 mm or less.

In the method of manufacturing a sealed battery, a sealed type in which a conductive connection tab bonded to a battery element is covered with a bonding auxiliary tab bonded to a portion having the same polarity as the conductive connection portion of the conductive connection tab and welded It is a method of manufacturing a battery. In the method for manufacturing a sealed battery, a joining auxiliary tab is joined to a conductive connecting portion in the battery, and the conductive connecting tab is positioned on a surface opposite to a joining surface of the joining auxiliary tab with the conductive connecting portion. It is a method of manufacturing a sealed battery, in which a battery is welded while being sandwiched between bent parts.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, when a conductive connecting tab joined to a battery element housed in a battery can is joined to a conductive connecting portion provided on the inner surface of the battery by welding, the conductive connecting tab is joined to the conductive connecting portion. By positioning the welded auxiliary tab on at least the upper surface of the conductive connection tab and welding, a nugget of a sufficient size can be formed even with a thin conductive connection tab, and a strong joint portion can be formed. It was found that it could be formed.

That is, by welding the conductive connection tab to the conductive connection portion by covering the conductive connection tab with the joining auxiliary tab joined to the conductive connection portion or the like, a sufficient welding current is supplied even when the conductive connection tab is thin. The nugget has a sufficient size, and a large contact portion can be formed. Further, since the joining auxiliary tab has one end joined to the conductive connection portion, the connection resistance is small by forming an energizing circuit between both surfaces of the conductive connection tab and the conductive connection portion on the inner surface of the battery. It is what

The present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a sealed battery of the present invention. Figure 1
(A) is a side view of the upper portion of the sealed battery of the present invention,
1 (B) to 1 (D) are A- in FIG. 1 (A).
It is a figure explaining the cross section in an A'line, and is a figure explaining in an assembly order. As shown in FIG. 1A, the conductive connection tab connected to the battery element is bonded to the conductive connection terminal provided on the battery header via the insulating member by the bonding auxiliary tab. In the sealed battery 1, after the battery element 3 is housed from the opening of the battery can 2, the one conductive connection tab 4 joined to the battery element 3 is attached to the battery header 5 that seals the opening of the battery can as an insulating member. It is connected to the electrode connection terminal 6 formed by providing 10 and the other conductive connection tab 7 is joined to the inner wall surface of the battery can.

In the battery shown in FIG. 1A, as shown in FIG. 1B, the battery element 3 is housed in the opening of the battery can 2 and the metal plate 8 of the battery header 5 is provided with the insulating member 10. It is produced by the battery header 5 in which the L-shaped joining auxiliary tab 11 is joined to the conductive connection terminal 6 provided via the. Figure 1 (C)
As shown in FIG.
With the conductive connection tab 4 in contact with A, the joining auxiliary tab 11
The rising portion 11B of B is bent and sandwiched. Further, as shown in FIG. 1 (D), the welding tip 12 of the resistance welding machine is used.
Are pressed against both sides of the joining auxiliary tab 11 and the conductive connection terminal 6 to perform welding. The welded portion may be further pressed after resistance welding.

FIG. 2 is a diagram for explaining another embodiment of the sealed battery of the present invention. FIG. 2 (A) is a side view of the upper portion of the sealed battery of the present invention, and FIGS. 2 (B) to 2 (D) are
It is a figure explaining the cross section in the BB 'line in FIG. 2 (A), and is a figure explaining in an assembly order. As shown in FIG. 2A, the sealed battery 1 accommodates the battery element 3 from the opening of the battery can 2, and the conductive connection tab 4 extending from the battery element 3 and the other conductive connection tab 7 are both Is also joined to the battery header 5.

As described above, when the conductive connection tabs of either polarity are joined to the battery header, even if the battery element moves in the battery can due to the impact when the battery is dropped,
As compared with the case where the conductive connection tab is joined to the wall surface of the battery can, it is possible to reduce the disconnection at the joint between the conductive connection tab and the battery header. Conductive connection tab 4 in FIG.
The connection of the battery header with the conductive connection portion is the same as that shown in FIG. As shown in FIG. 2B, the joining auxiliary tab 11 is joined to the portion of the metal plate 8 of the battery header 5.

Then, as shown in FIG. 2 (C), on the surface 11A opposite to the bonding surface of the bonding auxiliary tab 11 with the conductive connecting portion,
Joining auxiliary tab 11 with the other conductive connection tab 7 in contact
2 is bent so that both sides of the other conductive connection tab 7 are sandwiched by the joining auxiliary tabs 11,
As shown in (D), welding is performed by pressing the welding tip 12 of the resistance welding machine from both sides. Further, the welded portion may be pressed in addition to resistance welding.

FIG. 3 is a view for explaining another embodiment of the sealed battery of the present invention and is a partial perspective view. Figure 3 (A)
Is a joining auxiliary tab joined along the length direction of the metal plate 8 of the battery header 5. Since the joining auxiliary tab and the metal plate have a long contact surface, they are used for resistance welding. Can be joined at spaced welding points,
Since adjustment at the time of resistance welding becomes easy, more stable welding strength can be obtained. Next, as shown in FIG. 3 (B), the rising portion 11B of the joining auxiliary tab 11 is bent with the conductive connecting tab 4 being in contact with the surface 11A opposite to the joining surface of the joining auxiliary tab 11 with the conductive connecting portion. After sandwiching the conductive connection tab 4, as shown in FIG.
After the welding tip is pressed against the upper surface of the joining auxiliary tab 11 to join, the battery header 5 is attached to the opening of the battery can and sealed to obtain a sealed battery.

In the above description of FIGS. 1 to 3, the conductive connection tab joined to the battery element is welded by sandwiching both sides of the joining auxiliary tab, but only one side of the conductive connection tab is described. May be covered and joined by the joining auxiliary tab. Hereinafter, such an example will be described.

FIG. 4 is a view for explaining another embodiment of the sealed battery of the present invention, and FIGS. 4 (B) to 4 (D) show FIG.
It is a figure explaining the cross section in CC 'line in (A), and is a figure explaining in order of an assembly. As shown in FIG. 4A, the conductive connection tab connected to the battery element is bonded to the conductive connection terminal provided on the battery header via the insulating member by the bonding auxiliary tab. The sealed battery 1 is a battery can 2
After accommodating the battery element 3 through the opening, the one conductive connection tab 4 joined to the battery element 3 is formed by providing the insulating member 10 on the metal plate 8 of the battery header 5 that seals the opening of the battery can. The other conductive connection tab 7 is connected to the electrode connection terminal 6 and is joined to the inner wall surface of the battery can. As shown in FIG. 4 (B), the battery element 3 is housed in the opening of the battery can 2, and the conductive connection terminal 6 and the insulating member are provided on the metal plate 8 of the battery header 5 via the insulating member 10. Between 10 and L
The battery header 5 is manufactured by disposing the character-shaped joining auxiliary tabs 11 and caulking them. Next, as shown in FIG. 4C, the conductive connection tab 4 is brought into contact with the surface of the conductive connection terminal 6 and the rising portion 11B of the joining auxiliary tab 11 is bent, and as shown in FIG. Welding is performed by pressing the welding tip 12 from both sides. Further, the welded portion may be pressed in addition to resistance welding.

FIG. 5 is a view for explaining another embodiment of the present invention and is a perspective view of a part thereof. FIG. 5 (A) shows that the rising portion 11B of the joining auxiliary tab 11 joined to the battery header is joined from the end portion of the metal plate of the battery header toward the central portion of the battery header. The angle formed by the portion 11B and the metal surface of the battery header is an acute angle. Next, as shown in FIG. 5 (B), with the conductive connection tab 4 in contact with the metal surface of the battery header, the rising portion 11B of the joining auxiliary tab is pressed against the metal surface of the battery header, and as shown in FIG. ), A welding tip is pressed from above the joining auxiliary tab 11 to sandwich the joining tab and the conductive connection tab 4 on the metal surface of the battery header to join them together. After that, the conductive connection tab is bent, the battery header is attached to the opening of the battery can, and the meeting portion between the battery can and the battery header is sealed by laser welding to manufacture a sealed battery.

As described above, in the battery of the present invention, the conductive connecting tabs are welded in the state where the bonding auxiliary tabs are in contact with at least one surface, so that even when the conductive connecting tabs are thin,
A sufficiently large nugget is formed in the welded portion to form a joint having high strength. Therefore, even when the conductive connection tab is a thin tab having a thickness of 0.1 mm or less, it is possible to form a joint portion having high strength, and thus reliability can be improved. Further, it is preferable to use a bonding assist tab having a thickness of 0.1 mm to 0.15 mm. The material of the joining auxiliary tab is
The material is not limited to the same material as the conductive connection tab, and a material having good welding characteristics with the conductive connection tab or the like can be used.

[0021]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples. Examples and Comparative Examples (Preparation of Battery) A positive electrode active material layer containing lithium manganate having a spinel structure on both sides of an aluminum foil having a width of 40.1 mm, a length of 388 mm and a thickness of 20 μm was dried and then dried. Was applied to give a positive electrode having a thickness of 192 μm. The negative electrode has a width of 41.5 m.
It was prepared by applying a graphite-containing negative electrode active material layer to a copper foil of m, a length of 413 mm, and a thickness of 10 μm so that the thickness including the copper foil after drying was 130 μm. The thickness of the conductive connection tabs joined to the obtained positive electrode and negative electrode was 150 μm, 100 μm,
The electrode manufactured by changing to 50 μm was laminated in the order of microporous polyethylene membrane separator / positive electrode / microporous polyethylene membrane separator / negative electrode, and the spirally wound battery element was pressed by a 4.96 mm sizing press. After being compressed, it was housed in a battery can and connected with a conductive connection tab of 50 μm μm, a bonding auxiliary tab having a thickness of 0.1 mm was attached and bonded to a battery header. In a battery can, an electrolytic solution was prepared by dissolving LiPF ₆ in a mixed solvent consisting of 30 parts by volume of ethylene carbonate and 70 parts by volume of diethyl carbonate to a concentration of 0.8M, 0.9M and 1.0M. 3. After injecting the electrolytic solution, the electrolytic solution is sealed and lithium ion secondary batteries having different concentrations of lithium salts are produced, and the obtained lithium ion secondary battery is charged with a constant current up to a terminal voltage of 4.2 V. After switching from 2 V to constant voltage charging, the total charging time from the start of constant current charging was 7.5 hours and the charging was completed. The batteries were allowed to stabilize by leaving them at 30 ° C. for 14 days, defective products were removed, and eight rate characteristics were measured by the following method.

(Rate characteristic) After measuring the impedance, the battery was discharged at a discharge rate of 1C to measure the remaining capacity, recharged and then discharged at a discharge rate of 1C, and the capacity at that time was defined as 1C capacity. Next, after charging, the battery was discharged at a discharge rate of 0.2C to obtain a 0.2C capacity. These capacity ratios (1.0 C capacity / 0.2 C capacity) are expressed as 100 fractions and shown as rate characteristics in FIG.

[0023]

EFFECTS OF THE INVENTION The sealed battery of the present invention is a thin conductive connecting tab because the conductive connecting tabs to be joined to the battery element are welded to the conductive connecting terminals using the joining auxiliary tabs. Since the strength of the joint can be increased,
It is possible to provide a sealed battery having a small size, a large capacity, and high reliability.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a sealed battery of the present invention.

FIG. 2 is a diagram for explaining another embodiment of the sealed battery of the present invention.

FIG. 3 is a diagram illustrating another embodiment of the sealed battery of the present invention.

FIG. 4 is a diagram illustrating another embodiment of the sealed battery of the present invention.

FIG. 5 is a diagram for explaining another embodiment of the present invention.

FIG. 6 is a diagram illustrating a conventional sealed battery.

FIG. 7 is a diagram illustrating a relationship between tab thickness and rate characteristics.

[Explanation of Codes] 1 ... Sealed battery, 2 ... Battery can, 3 ... Battery element, 4 ... Conductive connection tab, 5 ... Battery header, 6 ... Connection terminal, 7 ... Other conductive connection tab, 8 ... Metal plate, 9 ... Liquid injection port, 10 ... Insulating member, 11 ... Joining auxiliary tab, 11A ... Opposite surface of joining surface,
11B: rising portion, 12: welding tip

Claims (2)

[Claims] 1. In a sealed battery, a conductive connecting tab bonded to a battery element is bonded to a conductive connecting portion inside the battery, and the conductive connecting tab is bonded to a portion having the same polarity as the conductive connecting portion. A sealed battery, which is covered with and welded to a conductive connection portion. 2. A method for manufacturing a sealed battery, wherein welding is performed with a conductive connection tab bonded to a battery element covered with a bonding auxiliary tab bonded to a portion having the same polarity as the conductive connection portion of the conductive connection tab. A method for manufacturing a sealed battery, comprising: