JP2002352791A - Battery - Google Patents

Abstract

(57) [Problem] To reduce internal resistance while reducing manufacturing cost. SOLUTION: The battery includes an electrode body 1 in which a positive electrode plate 1A and a negative electrode plate 1B are laminated via a separator 1C, an outer can 2 in which the electrode body 1 is put and sealed, A conductive tape disposed between the first electrode and the first electrode;
The conductive tape 3 is pressed against the inner surface of the outer can 2 by the electrode body 1 and is electrically connected thereto, and the heat welding adhesive layer 5 provided on the surface is thermally welded to the core material exposed portion 4 of one of the electrode plates. Electrical connection. The battery, via this conductive tape 3,
One electrode plate is electrically connected to the outer can 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery in which one electrode plate of an electrode body is connected to an outer can via a conductive tape.

[0002]

2. Description of the Related Art In a battery, one electrode plate of an electrode body is electrically connected to an outer can, and the other electrode plate is electrically connected to a convex electrode of a sealing plate. The structure for electrically connecting the electrode body to the outer can is roughly classified into two structures shown in FIGS. In the battery shown in FIG. 1, a metal plate 10 is welded to the exposed core member 4 of the electrode plate, and the metal plate 10 is spot-welded to the bottom of the outer can 2. The battery having this structure is manufactured as follows. The positive electrode plate 1A and the negative electrode plate 1B are laminated with the separator 1C interposed therebetween, and the resultant is spirally wound to manufacture the electrode body 1. The spiral electrode body 1 forms a core exposed portion 4 by exposing the cores of the positive electrode plate 1A and the negative electrode plate 1B at both ends. The metal plate 10 is connected to the exposed core member 4 of the spiral electrode body 1 by welding. The spiral electrode body 1 is put in the outer can 2. A welding electrode is inserted into the center of the spiral electrode body 1, and the metal plate 10 is pressed against the bottom of the outer can 2 with its tip, and the metal plate 10 is spot-welded to the bottom of the outer can 2 in this state. The other electrode plate, which is not connected to the outer can 2, is connected to the convex electrode 7 of the sealing plate 6 via a lead 8, and the sealing plate 6 is airtightly connected to the opening of the outer can 2 filled with the electrolyte. Fix it.

[0003] In the battery shown in FIG.
In contact with the inner surface. In the battery of this structure, it is not necessary to connect the metal plate to the outer can 2 by spot welding, and the electrode body 1 is put in the outer can 2 and connected to the outer can 2. Therefore, the outermost periphery of the electrode body 1 is an electrode plate connected to the outer can 2. Since the electrode body 1 has an active material layer laminated on the surface of the core, the outermost electrode plate is connected to the outer can 2 via the active material layer. Although the core of the electrode plate can be directly connected to the outer can without passing through the active material layer, in order to achieve this structure, it is necessary to remove the active material layer from the outermost electrode plate. The process is extremely laborious and increases the manufacturing cost. Therefore, in the battery having this structure, the outermost electrode plate is electrically connected to the outer can 2 via the active material layer.

[0004]

The internal resistance of the battery shown in FIG. 1 can be reduced. The exposed portion 4 of the core of the electrode plate is
This is because it is connected to the outer can 2 in a low-resistance state via the. However, the battery of this structure has a high manufacturing cost. The exposed core part 4 is welded to the metal plate 10, and further, with the electrode body 1 placed in the outer can 2, a welding electrode is inserted into the center of the spiral electrode body 1, and the metal plate 10 is connected to the outer can 2. This is because the connection is made by spot welding to the bottom. Also, in the battery having this structure, when the metal plate 10 is welded to the exposed core member 4 of the electrode plate, a blast may occur and welding failure may occur.

The battery shown in FIG. 2 can be manufactured at a lower cost than the battery shown in FIG. However, there is a disadvantage that the internal resistance increases. A battery having a large internal resistance cannot be charged and discharged with a large current, and its use is limited.

Therefore, in the conventional battery, the manufacturing cost increases when the internal resistance is reduced, and the internal resistance increases when the manufacturing cost is reduced. That is, there is a disadvantage that the manufacturing cost cannot be reduced and the internal resistance cannot be reduced. The present invention has been developed for the purpose of providing a battery capable of reducing the internal resistance while reducing the manufacturing cost.

[0007]

The battery of the present invention comprises an electrode body 1 in which a positive electrode plate 1A and a negative electrode plate 1B are laminated via a separator 1C, and an outer can in which the electrode body 1 is placed and hermetically sealed. 2 and a conductive tape 3 disposed between the outer can 2 and the electrode body 1. The conductive tape 3 is pressed against the inner surface of the outer can 2 by the electrode body 1 and is electrically connected thereto.
The heat-welding adhesive layer 5 provided on the surface is heat-welded to the exposed core member 4 of one of the electrode plates for electrical connection. The battery has one electrode plate electrically connected to the outer can 2 via the conductive tape 3.

[0008] The heat welding adhesive layer 5 can be a conductive adhesive. The conductive tape 3 can be a nickel foil or a metal foil whose surface is nickel-plated.
The heat welding temperature of the heat welding adhesive layer 5 can be 100 ° C to 200 ° C. The conductive tape 3 can extend from the bottom surface of the electrode body 1 to both side surfaces. The outer can 2 can be squeezed with the electrode body 1 inserted. Electrode body 1
Can be a spiral electrode in which a positive electrode plate 1A, a negative electrode plate 1B, and a separator 1C are stacked and spirally wound.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. However, the following examples illustrate a battery for embodying the technical idea of the present invention, and the present invention does not limit the battery to the following.

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”.
However, the members described in the claims are not limited to the members of the embodiments.

The battery of the present invention is a secondary battery such as a nickel-hydrogen battery, a nickel-cadmium battery or a lithium ion secondary battery. In particular, this structure is optimal for batteries used for applications that charge and discharge with a large current. FIG. 3 is a cross-sectional view illustrating a manufacturing process of the battery according to the embodiment of the present invention. The battery shown in FIG. 1 includes an electrode body 1, an outer can 2 containing and sealing the electrode body 1, and a conductive tape 3 connecting one electrode of the electrode body 1 to the outer can 2. .

The electrode body 1 has a positive electrode plate 1A and a negative electrode plate 1B laminated on each other with a separator 1C interposed therebetween. The electrode body 1 is a spiral electrode body in which a laminate of a positive electrode plate 1A, a negative electrode plate 1B, and a separator 1C is spirally wound, or a rectangular positive electrode plate, a negative electrode plate, and a separator. The electrode body 1 has a core exposed portion 4 on which no active material is applied, provided on a positive electrode plate 1A and a negative electrode plate 1B. The exposed portion 4 of the core material is
Are provided projecting up and down. The exposed core material portion 4 of the positive electrode plate 1A and the exposed core material portion 4 of the negative electrode plate 1B protrude from the opposite end of the electrode body 1. For example, the core exposed portion 4 of the negative electrode plate 1B is provided at the lower end of the electrode body 1, and the core exposed portion 4 of the positive electrode plate 1A is provided at the upper end of the electrode body 1. The exposed core material 4 provided at the lower end of the electrode body 1 is connected to the outer can 2 via a conductive tape 3, and the exposed core material 4 provided at the upper end of the electrode body 1 is connected via a lead 8. Convex electrode 7 of sealing plate 6
Connected to.

The outer can 2 is manufactured by pressing a metal plate into a tubular shape having a closed bottom. The outer can 2 is press-formed into a cylindrical or rectangular tube shape. The outer can 2 in which the spiral electrode body is placed is formed into a cylindrical shape, and the outer can in which a rectangular parallelepiped electrode body in which a positive electrode plate and a negative electrode plate cut into a square are laminated is formed into a rectangular cylindrical shape. The outer can 2 is made of a metal plate, an aluminum plate, or an aluminum alloy plate in which the surface of iron is nickel-plated.

The outer can 2 has an opening hermetically closed by a sealing plate 6. The sealing plate 6 is airtightly fixed by caulking the outer can 2 or is airtightly fixed by laser welding. Sealing plate 6 that is laser-processed and fixed to outer can 2
Are insulated with an insulating material to fix the convex electrode 7. The sealing plate 6 fixed by caulking to the outer can 2 can be fixed to the outer can 2 with insulation via an insulating material. Therefore, the sealing plate 6 can be provided by pressing the convex electrode 7.

The electrode body 1 is formed by connecting one electrode plate to the conductive tape 3.
And the other electrode plate is connected to the projection electrode 7 of the sealing plate 6 via a lead 8. The conductive tape 3 is provided with a core material exposed portion 4 of the electrode plate via a heat welding adhesive layer 5.
Connected to. When heated, the adhesive layer 5 is softened or melted to connect the exposed core material 4 to the conductive tape 3.
A conductive adhesive is used for the heat welding adhesive layer 5. As the conductive adhesive, one obtained by mixing a conductive powder such as carbon or metal powder with a thermoplastic synthetic resin is used. A hot melt adhesive is used as the thermoplastic synthetic resin.
The heat welding adhesive layer 5 makes the heat welding temperature higher than the maximum temperature in the usage environment of the battery. This is because when the battery becomes hot in a state where the battery is used, the heat welding adhesive layer 5 is melted so that the exposed core material 4 does not separate from the conductive tape 3. Therefore, the heat welding adhesive layer 5 has a heat welding temperature of 100
C. to 200.degree. C., preferably 120 to 180.degree.

The conductive tape 3 is provided with a heat welding adhesive layer 5 on the surface for connecting the exposed core material 4. In the battery shown in the figure, the core exposed portion 4 is connected to the upper surface of the conductive tape 3. Therefore, the conductive tape 3 is provided with the heat welding adhesive layer 5 only on the upper surface. The lower surface of the conductive tape 3 is in direct contact with and electrically connected to the outer can 2 without providing the heat welding adhesive layer 5. However, the conductive tape 3 provided with the conductive heat welding adhesive layer 5 may be provided with the heat welding adhesive layer 5 on both sides. This is because the conductive tape 3 can be electrically connected to the outer can 2 via the conductive heat bonding adhesive layer 5.

The conductive tape 3 is a metal foil. Metal foil is
It is a nickel foil or a metal foil whose surface is nickel-plated. The conductive tape 3 can be deformed in a state of being closely adhered along the bottom surface and side surfaces of the electrode body 1, and can be sandwiched in a narrow gap between the electrode body 1 and the outer can 2. The thickness of the metal foil is, for example, 50 μm to 200 μm.

In the battery shown in the figure, the conductive tape 3 extends from the bottom surface of the electrode body 1 to both side surfaces. This battery has an electrode body 1
The conductive tape 3 is sandwiched between both sides of the outer can 2 and the inner surface of the outer can 2.
Therefore, the contact resistance between the conductive tape 3 and the outer can 2 can be reduced, and the internal resistance of the battery can be reduced. In particular, the battery having this structure has a feature that the outer can 2 containing the electrode body 1 can be squeezed and the conductive tape 3 can be electrically connected to the inner surface of the outer can 2 with a lower resistance. However, the battery of the present invention
It is not necessary to extend the conductive tape 3 to the side surface of the electrode body 1.

In the battery shown in the figure, a conductive tape 3 is connected to the bottom surface of the spiral electrode body 1, and this conductive tape 3 is bent at right angles on both sides along the electrode body 1 so as to be in close contact with both side surfaces of the electrode body 1. I have. The conductive tape 3 adhered to both side surfaces of the cylindrical spiral electrode body 1 is bent along the outer peripheral edge of the circular bottom surface of the spiral electrode body 1. Since the conductive tape 3 as a metal foil can be freely deformed, it can be bent at a right angle along the outer peripheral edge of the spiral electrode body 1.

The battery having the above structure is manufactured as follows. As shown in FIG. 3, the core material exposed portion 4 of the electrode body 1
To the conductive tape 3. The conductive tape 3 is brought into contact with the lower surface of the electrode body 1 such that the heat welding adhesive layer 5 is brought into contact with the exposed core material 4. Further, both sides of the conductive tape 3 are bent along both side surfaces of the electrode body 1. The conductive tape 3 is placed on the hot plate 9, and the conductive tape 3 is heated by the hot plate 9. The heated conductive tape 3 melts the heat welding adhesive layer 5 and heat welds the exposed core material 4 of the electrode body 1. After the electrode body 1 to which the conductive tape 3 is thermally welded is put into the outer can 2 and filled with the electrolytic solution, the opening of the outer can 2 is airtightly closed by the sealing plate 6. The sealing plate 6 is airtightly fixed to the outer can 2 by caulking or laser welding. At this time, the other electrode plate of the electrode body 1
Is connected to the protruding electrode 7 of the sealing plate 6. afterwards,
The outer shape of the outer can 2 is reduced by squeezing the can. When the outer can 2 becomes thinner, the conductive tape 3 is strongly sandwiched between the electrode body 1 and the outer can 2 and is electrically connected to the outer can 2 in a low-resistance state.

In the above process, when 100 SC-size cylindrical nickel-cadmium batteries were trial-produced, the internal resistance of the trial-produced battery was reduced through the metal plate shown in FIG.
Was connected to the outer can 2, and no explosive welding failure occurred. However, conductive tape 3
Was thermally welded to the electrode body 1 at 150 ° C.

[0022]

The battery of the present invention has the feature that the internal resistance can be reduced while reducing the manufacturing cost. This is because the battery of the present invention has a conductive tape disposed between the outer can and the electrode body, and the conductive tape electrically connects one electrode plate to the outer can. The conductive tape is electrically welded with the heat-welded adhesive layer provided on the surface thereof to the exposed portion of the core material of one of the electrode plates, and is electrically connected to the inner surface of the outer can with the electrode body. . For this reason, unlike the conventional case, the electrode plate can be electrically connected to the outer can without increasing the production cost by welding and without causing welding failure due to the explosion. In addition, since the conductive tape is electrically connected to the exposed portion of the electrode plate by heat welding, the internal resistance can be reduced. Therefore, the battery of the present invention can be mass-produced at low cost while reducing the internal resistance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the internal structure of a conventional battery.

FIG. 2 is a sectional view showing the internal structure of another conventional battery.

FIG. 3 is a schematic sectional view showing a manufacturing process of the battery according to the embodiment of the present invention.

[Explanation of symbols]

1: Electrode body 1A: Positive electrode plate 1
B ... Negative electrode plate 1C ... Separator 2 ... Outer can 3 ... Conductive tape 4 ... Core material exposed portion 5 ... Heat welding adhesive layer 6 ... Sealing plate 7 ... Convex electrode 8 ... Lead 9 ... Hot plate 10 ... Metal plate

Claims (7)

[Claims] A positive electrode plate (1A) and a negative electrode plate (1B) are separated by a separator (1).
C), an electrode body (1) laminated via the electrode body (1), an outer can (2) in which the electrode body (1) is put and hermetically sealed, and the outer can (2) and the electrode body (1). An outer can (2) with an electrode body (1) arranged between them
The heat-bonded adhesive layer (5), which is pressed against the inner surface of the electrode plate and electrically connected thereto, and provided on the surface, exposes the core material exposed portion (4) of one of the electrode plates.
And a conductive tape electrically connected to the outer can by electrically connecting one of the electrode plates to the outer can. 2. The battery according to claim 1, wherein the heat-sealing adhesive layer is a conductive adhesive. 3. The battery according to claim 1, wherein the conductive tape (3) is a nickel foil or a metal foil whose surface is nickel-plated. 4. The heat welding temperature of the heat welding adhesive layer (5) is 100.
The battery according to claim 1, wherein the temperature is in the range of from about 200C to about 200C. 5. The battery according to claim 1, wherein the conductive tape (3) extends from the bottom surface to both side surfaces of the electrode body (1). 6. The battery according to claim 1, wherein the outer can (2) is squeezed with the electrode body (1) put therein. 7. An electrode assembly (1) comprising a positive electrode plate (1A) and a negative electrode plate (1B)
The battery according to claim 1, which is a spiral electrode formed by laminating a spiral and a separator (1C).