JP2000138046A - Sealed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed battery having a structure lessened in connecting resistance in the case of a serial connection, without reducing in connecting strength. SOLUTION: A connecting member 11 for connecting another sealed battery A in series is integrally attached to an upper part or a lower part, and has a bottom part connected to a sealing plate 5 constituting the upper sealed part of a battery can. In addition, the upper part of the connecting member 11 forms an opening part 11a capable of housing the can bottom of another sealed battery A. A gas hole 5a for controlling battery internal pressure is formed on the sealing plate 5, and a valve element 8 for closing the gas hole 5a is provided on the upper surface of the sealing plate 5. At the same time, the valve element 8 is sealed with the bottom part of the connecting member 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed battery,
More specifically, the present invention relates to a sealed battery provided with a connecting member capable of reducing a connection resistance between the batteries when a large number of sealed batteries are connected in series to achieve a large current discharge.

[0002]

2. Description of the Related Art An alkaline secondary battery typified by a nickel-hydrogen secondary battery and a nickel-cadmium secondary battery is formed by, for example, spirally winding a sheet in which a positive electrode sheet and a negative electrode sheet are laminated via a separator. The electrode group is housed in a battery can having an open top together with a predetermined alkaline electrolyte, and the upper end of the battery can is sealed.

One example of such a sealed battery is shown in FIG. 7 for a nickel-hydrogen secondary battery capable of extracting a large current. First, a negative electrode sheet 1a carrying a hydrogen storage alloy powder, a separator 1b such as a polypropylene nonwoven fabric, and a positive electrode sheet 1c carrying a nickel hydroxide powder as a positive electrode active material are superposed in this order, and the positive electrode sheet 1c side Then, the negative electrode sheet 1a is spirally wound so that the negative electrode sheet 1a is on the outside, and then the core is removed to form an electrode group 1 having an outer diameter and a height of a predetermined dimension.

[0006] The electrode group 1 is housed in a battery can 2 having a predetermined inner diameter and height. At this time, since the negative electrode sheet 1a of the electrode group 1 contacts the inner wall of the battery can 2, the battery can 2 functions as a negative electrode terminal. A negative electrode current collector plate 3 having substantially the same diameter as the outer diameter of the electrode group 1 is welded to the lower end surface of the negative electrode sheet 1 a of the electrode group 1. The contact between the negative electrode sheet 1a and the battery can 2 is established.

[0005] Further the upper end surface of the positive electrode sheet 1c of the electrode group 1, the positive electrode conductive member a ₀ as shown in FIG. 8 are arranged. The positive electrode conducting member a ₀ has an edge portion of the positive electrode current collector plate 4 having substantially the same size as the outer diameter of the electrode group 1 and an edge portion of the sealing plate 5 having a gas hole 5a for controlling the internal pressure of the battery at the center. After welding both ends of the strip-shaped lead member 6, the lead member 6 is bent, and the positive electrode current collector plate 4 is positioned below and the sealing plate 5 is positioned above.

[0006] Further, a material in which the positive electrode current collector plate 4 and the lead member 6 are integrated with each other may have a structure in which the lead member side is bent and its end is welded to the edge of the sealing plate 5. Good. As described above, when the battery is assembled by disposing the negative electrode current collector 3 and the positive electrode current collector 4 at the lower part and the upper part of the electrode group 1, respectively, a larger current is taken out as compared with the case of the battery having no such arrangement. be able to.

The above-mentioned sealing plate 5 is disposed in the upper opening of the battery can 3 with the insulating ring 7 attached to the periphery thereof, and the upper opening is subjected to, for example, caulking to form the sealing plate 5 with the sealing plate 5. The space between the battery cans 3 is formed in a sealed structure. On the gas hole 5a, a valve body 8 made of an elastic material such as rubber is disposed so as to close the gas hole 5a, and the positive electrode terminal 9 is disposed in a state of enclosing the valve body 8, The periphery is spot-welded to the sealing plate 5, for example, to form an airtight structure.

Therefore, in this sealed nickel-metal hydride secondary battery, an insulating ring 7
An upper sealed portion composed of the sealing plate 5, the valve body 8, and the positive electrode terminal 9 is formed, the battery can 2 functions as a negative electrode terminal, and the positive electrode terminal 9 and a part of the sealing plate 5 function as a positive electrode terminal. It has a structure. When the internal pressure of the battery rises due to gas generation due to self-discharge of the battery, the generated gas pushes up the valve element 8 from the gas hole 5a, and the positive electrode terminal 9 and the sealing plate 5
The structure has a structure in which an abnormal increase in battery internal pressure is automatically suppressed by leaking to the outside from the gap.

Recently, the use of a sealed battery such as a nickel-hydrogen secondary battery as a driving source for various electric tools, electric assist bicycles, and electric vehicles has been studied. In that case, a plurality of batteries are connected in series to form an electrode group with an increased operating voltage,
Further, it has been practiced to form an entire system capable of extracting a large current by connecting the electrode groups in parallel.

[0010] In this case, if the connection between the batteries is poor, heat generation or voltage drop may occur at the connection location. In particular, when batteries having a structure capable of discharging a large current as shown in FIG. 7 are used, the above-described problems are likely to occur when these batteries are connected to each other. Conventionally, for example, when the sealed batteries shown in FIG. 7 are connected in series in the vertical direction, as shown in FIG. 9, an insulating plate 10 having a hole through which a positive electrode terminal 9 can be inserted is provided on the upper portion of the battery. The connecting member 11 having a container shape having an inside diameter capable of accommodating the bottom of another can of a sealed battery is disposed thereon, and the bottom of the connecting member 11 and the upper surface of the positive electrode terminal 9 are welded to each other to perform the connection. The member 11 is integrally mounted on the upper part of the battery, and another sealed battery is connected to the connecting member 11 one after another.

However, in this connection mode, since the connection member 11 and the battery are only welded on the upper surface of the positive electrode terminal 9, the connection strength is weak as a whole. And the conduction between the positive electrode terminal 9 and the connecting member 11 is only one central portion of the connecting member.
However, there is a problem that the connection resistance when another sealed battery is arranged is not so reduced.

Further, as shown in FIG. 10, a connecting member 11 having a projection 11b formed at the center of the bottom and surrounding the projection 11b and having a donut-shaped groove 11c is arranged at the upper part of the battery and connected. There is also known a connection mode in which the projection 11b of the member 11 and the upper surface of the positive electrode terminal 9 and the groove 11c and the upper surface of the sealing plate 5 are welded to each other to integrate them.

In this case, since there are two conductive locations, that is, the location of the positive electrode terminal 9 and the location of the sealing plate, the connection resistance is reduced as compared with the state shown in FIG. However,
When the size of the sealed battery is small, the location of the sealing plate for welding the groove portion 11c is also small, which makes the welding work of the two difficult, and at the same time, the heat transfer path of the heat generated at the welding portion becomes relatively long, so that welding is performed. There is a problem that heat is easily stored in the portion, and as a result, thermal deterioration of the valve body 8 is likely to occur.

[0014]

SUMMARY OF THE INVENTION According to the present invention, when a sealed battery, particularly a sealed battery capable of discharging a large current, is connected in series, the connection resistance at the connection portion is reduced and heat generation and voltage drop occur. It is an object of the present invention to provide a sealed battery having a structure that makes it difficult to inhibit large current discharge characteristics.

[0015]

In order to achieve the above object, the present invention is characterized in that a connecting member for connecting another sealed battery in series is integrally mounted on the upper or lower part. Is provided. Specifically, the connection member has a bottom portion connected to a sealing plate constituting an upper sealing portion of the battery can, and an upper portion thereof is an opening capable of accommodating the bottom portion of another sealed battery, and A gas hole for controlling the internal pressure of the battery is formed in the sealing plate, and a valve element for closing the gas hole is disposed on an upper surface of the sealing plate,
A sealed battery is provided in which the valve body is sealed at the bottom of the connecting member.

Further, in the present invention, a positive electrode conducting member, which is an integrated structure of a plate body portion having an outer shape similar to that of the sealing plate and a positive electrode current collector plate, is accommodated. A sealed battery is provided that is connected to Utaka Ban in surface contact.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sealed battery according to the present invention will be described below with reference to the drawings. FIG. 1 shows an example A of the sealed battery of the present invention.
FIG. 2 is a partially cutaway exploded perspective view of FIG. In this battery A, a spiral electrode group 1 including a negative electrode sheet 1a, a separator 1b, and a positive electrode sheet 1c is accommodated in a battery can 2, and a negative electrode current collector 3 is disposed at a lower end of the electrode group 1. This is not different from the conventional battery structure shown in FIG.

However, in the case of the battery A, the upper sealed portion of the battery can 2 has the following structure as shown in FIG.
This is different from the battery structure of FIG. First, a positive electrode conducting member a as shown in FIG. That is, the positive electrode conducting member a is composed of a positive electrode current collector plate 4 having substantially the same size as the outer diameter of the electrode group 1 and a plate body portion 4b to be described later.
Are bent at the bridge portion 4a, and the plate portion 4b is connected to the sealing plate 5 by the bridge portion 4a.
Are members that are welded to each other and connected in a surface contact state.

Here, the outer diameter of the plate portion 4b has a similar shape slightly smaller than that of the sealing plate 5, and a gas hole 5b corresponding to the gas hole 5a of the sealing plate 5 is formed in the center portion. It has a donut shape as a whole. The positive electrode conducting member a is composed of a strip-shaped lead member 6 and a positive current collector plate 4 and a sealing plate 5.
As compared with the conventional member a ₀ shown in FIG. 8 that is connected to,
Since the contact area between the plate portion 4b and the sealing plate 5 is large, it is possible to reduce the connection resistance at the connection portion between them.

The positive electrode conducting member a illustrated in FIG. 3 is to be incorporated in a cylindrical battery. When the target sealed battery is rectangular, the sealing plate is generally rectangular, and the positive electrode conducting member incorporated in the battery has a shape as shown in FIG. That is, the rectangular positive electrode current collector plate 4
And a plate portion 4b having an outer shape similar to that of the sealing plate 5 and having a gas hole 5b formed at a central portion thereof.
The plate body portion 4b of the members connected by a is welded to the sealing plate 5.

The positive electrode current collector plate 4 in the positive electrode conducting member a
And the upper end surface of the positive electrode sheet 1 c of the electrode group 1, and the battery can 2
By performing a caulking process on the upper opening of the battery pack, a sealed structure is formed between the sealing plate 5 and the battery can 2. The gas hole 5a of the sealing plate 5 is closed so that the valve body 8 is disposed, and a donut-shaped insulating plate 10 is provided around the upper periphery of the battery can 2.
Are arranged, and a connecting member 11 described later is integrally attached to the sealing plate 5 in a state in which the valve body 8 and the insulating plate 10 are pressed against each other, thereby forming an upper sealed portion.

This connecting member 11 has a shallow container shape manufactured by, for example, deep drawing of a thin conductive plate material, and the upper portion thereof is another sealed type battery as shown by a virtual line in FIG. The opening 11a has an inner diameter that can accommodate the bottom of the can. In the center of the bottom is formed a projection 11b whose lower side is a recessed part capable of accommodating the above-described valve element 8, and surrounds the periphery thereof to form a donut-shaped groove 1
1c is formed.

The connecting member 11 is placed on the sealing plate 5 via the insulating plate 10. The valve body 8 which is disposed so as to close the gas hole 5a of the sealing plate 5 is accommodated in the lower concave portion of the central projection 11b, and the bottom of the groove portion 11c is the sealing plate 5
In direct contact with the upper surface of the By welding the bottom of the groove 11c and the sealing plate 5, the valve element 8 is
b, and is hermetically integrated with the battery can (negative electrode terminal) 2 on the sealing plate in an insulated state via the insulating plate 10 and the insulating ring 7. Is done.

Therefore, in the connecting member 11, the projection 11b functions as a positive electrode terminal at the same time as functioning as a sealing member for the valve body 8, and the entire connecting member 11 also functions as a positive electrode terminal. Since the groove 11c is welded to the entire donut-shaped portion of the sealing plate 5, the welding strength between the two increases, and the two are connected in a surface contact state. Reduce.

When the target sealed battery is a prismatic battery, the connecting member 11 also has a rectangular outer shape, and the groove 11c is not a donut shape but a protrusion 1
It is a square groove corresponding to the shape of 1b. FIG.
3 shows another sealed battery B of the present invention. In the case of the battery B, a connecting member 11 having a flat bottom surface is used. The sealing plate 5 has a valve body 8 at the center.
Is formed. That is, as the sealing plate 5, a donut-shaped projection 5d
Are used.

Then, the valve body 8 is housed in the recess 5c, the valve body 8 is sealed and the connecting member 11 is disposed via the insulating plate 10, and the bottom of the connecting member 11 is in contact with the upper surface of the donut-shaped projection 5d. They are integrally attached by welding. In the case of this connection structure, the bottom of the connection member 11 functions as a sealing member for the valve body 8 and serves as a positive electrode terminal as a whole. Since the welding location is the entire upper surface of the projection 5d of the sealing plate, the welding strength between the two is large and the connection resistance between the two is reduced.

FIG. 6 shows still another sealed battery C. In the case of this battery C, the recess 5c and the protrusion 5d are formed in the sealing plate 5 in the same manner as the battery B shown in FIG.
The central part of the bottom of the connecting member 11 is a flat surface that is entirely recessed and recessed, and the flat surface seals the valve element 8 and is integrated with the upper surface of the protrusion 5d by welding. Is different.

Also in this case, the welding portion is formed by the projection 5d.
The connection member 11 and the sealing plate 5 are in a surface-connected state because of the entire upper surface, so that the contact strength between them and the connection resistance are reduced.

[0029]

As is apparent from the above description, in the sealed battery of the present invention, since the connecting member is welded and integrated with the sealing plate in a surface connection state, the connection strength between the connecting member and the sealing plate is increased. And the connection resistance between them is also reduced. Therefore, even when the bottom of the can of this sealed battery is arranged on the connecting member to form an electrode group in which a plurality of batteries are connected in series, phenomena such as voltage drop and heat generation due to the increase in resistance at the connecting portion. Is less likely to occur. In particular, when the target battery is a battery capable of extracting a large current, the sealed battery of the present invention is effective in that the electrode group can be formed without obstructing the large current discharge characteristics of the battery.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a battery example A of the present invention.

FIG. 2 is a partially cutaway exploded perspective view of a battery A.

FIG. 3 is a perspective view showing an integrated structure of a positive electrode current collector plate and a sealing plate incorporated in a battery A.

FIG. 4 is a perspective view showing another positive electrode conducting member.

FIG. 5 is a partial sectional view showing a battery example B of the present invention.

FIG. 6 is a partial cross-sectional view showing a battery example C of the present invention.

FIG. 7 is a cross-sectional view showing a conventional sealed battery.

8 is a perspective view showing an integrated structure of a positive electrode current collector plate and a sealing plate incorporated in the battery of FIG.

FIG. 9 is a partial cross-sectional view showing a conventional battery equipped with a connecting member.

FIG. 10 is a partial sectional view showing a conventional battery to which another connecting member is attached.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode group 1a Negative electrode sheet 1b Separator 1c Positive electrode sheet 2 Battery can 3 Negative current collecting plate 4 Positive current collecting plate 4a Bridge 4b Disk portion 5 Sealing plate 5a Gas hole 5b Gas hole 5c Depression of sealing plate 5d Projection of sealing plate 6 Lead member 7 Insulating ring 8 Valve 9 Positive electrode terminal 10 Insulating plate 11 Connecting member 11a Opening of connecting member 11b Protrusion of connecting member 11 11c Groove of connecting member 11

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) AA01 BB05 CC01 CC08 CC24

Claims (4)

[Claims] 1. A sealed battery, wherein a connection member for connecting another sealed battery in series is integrally mounted on an upper portion or a lower portion. 2. The connecting member has a bottom portion connected to a sealing plate constituting an upper sealing portion of the battery can, and an upper portion formed as an opening capable of accommodating the can bottom portion of another sealed battery. 1 sealed battery. 3. A gas hole for controlling the internal pressure of the battery is formed in the sealing plate, a valve element for closing the gas hole is disposed on an upper surface of the sealing plate, and the valve element is sealed at a bottom of the connecting member. 3. The sealed battery according to claim 2, wherein said battery is stopped. 4. A positive electrode conducting member, which is an integrated structure of a plate body having a similar external shape to the sealing plate and a positive electrode current collecting plate, is accommodated, and the plate body faces the sealing plate. 4. The sealed battery according to claim 2, which is connected in a contact state.