JP2002324571A - Electrode group of cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode group of a cell, capable of preventing shorting caused by foreign matters in a bag-like separator and also preventing facility contamination due to flying active material. SOLUTION: While either a positive electrode or a negative electrode, for example a positive electrode 2, is covered with a bag-like separator 4, a negative electrode and the positive electrode 2 are alternately laminated to provide an electrode group of a cell in which the negative electrode and the positive electrode 2 are laminated with the separator 4 in between. The entire circumference of the separator 4 is sealed with an adhesive seal 9 on three sides of the separator 4 and an adhesive 11 at an opening part 10, along four sides of the positive electrode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a group of electrodes of a battery, and more particularly to a group of electrodes formed by alternately stacking a negative electrode plate and a positive electrode plate with either a negative electrode plate or a positive electrode plate covered with a bag-shaped separator. Things.

[0002]

2. Description of the Related Art A prismatic battery is constructed by inserting a plurality of square negative electrode plates and positive electrode plates alternately laminated via a separator into a battery case together with an electrolytic solution. Also, in the electrode plate group, as a method of laminating a separator between the negative electrode plate and the positive electrode plate, the negative electrode plate and the positive electrode plate are alternately laminated with the bag-shaped separator attached to the positive electrode plate or the negative electrode plate. Is known.

As shown in FIG. 7 (a), a lead plate 32 having a lead plate 33 fixed to one side of a rectangular electrode plate 31 protrudes as an electrode plate having a bag-like separator mounted thereon. The bag-shaped separator 3 is formed so as to cover almost the entire surface of the electrode plate 31 except for the lead portion 32 from the other side of the electrode plate 31.
As shown in FIG. 7 (b), the lead portion 38 extending upward from the non-coated portion 36a of the active material formed on the upper edge portion of the rectangular electrode plate 36 as shown in FIG. The formed lead plate 37 is formed by seam welding, and a bag-shaped separator 39 is provided so as to cover substantially the entire surface of the electrode plate from below the electrode plate 36.
Is known.

[0004]

However, in the case where the electrode plates 31 and 36 are covered with the bag-shaped separators 34 and 39 as described above, the electrode plates 31 and 36 and the lead portions 32 and 38 are provided.
The openings 35 and 40 are kept open to draw out. When assembling the electrode plate group using the electrode plates 31 and 36, foreign matter is mixed in from outside to cause a short circuit, or the electrode plates 31 and 36 may be shorted. , 36 are removed from the opening 35,
There is a problem such as scattering from 40 and contaminating equipment in a subsequent process.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a battery electrode plate group capable of preventing occurrence of a short circuit due to entry of foreign matter into a bag-like separator and preventing equipment contamination due to scattering of an active material. It is an object.

[0006]

The electrode group of the battery according to the present invention comprises a negative electrode plate and a positive electrode plate which are alternately arranged with a bag-shaped separator placed on at least one of the negative electrode plate and the positive electrode plate. By stacking, in a battery electrode plate group in which a negative electrode plate and a positive electrode plate are stacked with a separator interposed therebetween, the entire periphery of the separator is sealed along the four sides of the electrode plate, and the entire periphery of the bag-shaped separator is sealed. Is sealed so that no foreign matter is mixed into the bag-shaped separator during the assembly process of the electrode plate group, and there is no danger of short-circuiting. Contamination can also be prevented.

Specifically, the separator is melt-sealed around the lead portion of the electrode plate and its surroundings except for the vicinity thereof by ultrasonic heating or heating with a hot plate.
The entire circumference can be sealed by bonding and sealing the separator with an adhesive, or by melting and sealing the separator through a hole formed in the lead portion.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the electrode group of the battery of the present invention is applied to a nickel-metal hydride battery will be described below with reference to FIGS.
This will be described with reference to FIG.

In FIG. 1, an electrode group 1 is composed of n positive electrode plates 2, (n + 1) negative electrode plates 3, and a bag-shaped separator 4 covered on each positive electrode plate 2. The negative electrode plate 3 and the positive electrode plate 2 are alternately stacked with the plate 2 covered with the separator 4.

The positive electrode plate 2 and the negative electrode plate 3 are protruded from opposite sides in a laminated state, and the protruding portions are constituted by lead portions 2a and 3a which are not coated or filled with an active material. Current collector plates 5 and 6 are integrally joined to the side edges of the leads 2a and 3a, respectively.

In FIG. 2, a positive electrode plate 2 is formed by filling a positive electrode active material into a core material made of a foamed metal of Ni, and has a lead portion 2a protruding from one side thereof over substantially the entire length except for both ends. Is formed. This lead part 2a
Is formed by pressurizing and compressing a foamed metal and seam-welding a lead plate 7 to one surface thereof. The lead portion 2a has a plurality of positioning holes 8 for positioning each positive electrode plate 2 and the current collector plate 5 so as to align their side edges when they are joined.
a and 8b are formed.

The separator 4 is made of a non-woven fabric of a synthetic resin fiber or a porous synthetic resin sheet, and has a size to completely cover the active material filled region of the positive electrode plate 2, and three sides except for the side corresponding to the lead portion 2 a are welded. The other side is formed in a bag shape having an opening 10 for inserting the positive electrode plate 2 and projecting the lead 2a. An adhesive 11 such as, for example, a thermosetting adhesive is applied to the inner surface of the opening 10 of the separator 4 in advance. After the positive electrode plate 2 is inserted, the opening 10 is heated and pressurized to project the lead 2a. It is sealed in the state where it was made to be.

Incidentally, the negative electrode plate 3 is formed by applying a negative electrode constituent material to a punching metal of Ni except for the lead portion 3a.

According to the electrode plate group 1 having the above structure, the positive electrode plate 2
The three sides of the separator 4 excluding the side where the lead portion 2a protrudes are sealed with a welding seal 9, the side where the lead portion 2a protrudes is also adhesively sealed with an adhesive 11, and the entire periphery of the separator 4 is sealed. Therefore, during the assembly process of assembling the electrode plate group 1 by alternately stacking the negative electrode plate 3 and the positive electrode plate 2 covered with the separator 4, the current collector plates 5 and 6 are joined, and various inspection processes are further performed. Thus, during the subsequent manufacturing process of inserting and arranging in the battery case together with the electrolytic solution, there is no possibility that foreign matter enters the bag-shaped separator 4 and the risk of short-circuiting can be eliminated. Also, it is possible to prevent the active material that has peeled off from the positive electrode plate 2 from scattering from the opened opening 10 and contaminating equipment in a subsequent process.

An electrode group 1 using a positive electrode plate 2 in which the entire periphery of a separator 4 of the present embodiment is sealed, and an electrode group 1 using a conventional positive electrode plate in which an opening 10 of a separator 4 is opened are described. When a short-circuit defect inspection was performed, the defect rate was 0.10% in the conventional example, but the defect rate was reduced to half, that is, 0.05%. In particular, the defect occurrence rate in the region a closest to the lead portion 2a in the region where the positive electrode plate 2 is divided into three equal portions between the edge on the lead portion 2a side and the edge on the opposite side is 0.1% in the conventional example. What was 06%, but 0.02%
By sealing the opening 10, the defect occurrence rate in the region near the opening 10 where short-circuit failure is likely to occur is reduced to 3
It was reduced to one part.

In the short-circuit failure inspection, as shown in FIG. 3, the electrode plate group 1 is set on a pressing means 12 comprising a pressing jig 13 and a pressing tool 14 such as a cylinder device. Are connected to the output terminals 15a and 15b of the short-circuit inspection device 15, and the inspection is performed. The short-circuit inspection device 15 connects a capacitor 18 to a power supply 16 via a first switch 17, and connects the current detector 1 between the capacitor 18 and both output terminals 15a and 15b.
9 and a switch 20.

At the time of the short-circuit inspection, the thickness of the separator 4 is compressed and held from t1 to t2 by applying a load of about 4000 N to the electrode plate group 1 by the pressing means 12. This compression amount is determined by the thickness of the separator 4 having an initial thickness of t1
Is based on the fact that the thickness of the separator 4 becomes stable at t2 after repeating the charging and discharging of the battery a predetermined number of times (about 100). Next, the second switch 20 is opened, the first switch 17 is closed, and the capacitor 18 is charged. When the charging is completed, the first switch 17 is opened with an applied voltage of 400 V,
The second switch 20 is closed to energize the electrode plate group 1, and the energizing current at that time is measured by the current detector 19. If there is no short-circuit, no short-circuit current flows, so that the quality can be determined.

In this short-circuit inspection, the electrode plate group 1 using the positive electrode plate 2 having the entire periphery of the separator 4 sealed as described above.
In this case, the defective rate was significantly reduced as compared with the conventional example.

In the above description, the opening 1 of the separator 4
In the example shown in FIG. 4, the sealing was performed with the adhesive 11 applied to the inner surface of the positive electrode plate 2.
Holes 21 (e.g., holes 1 mm in diameter
The opening 10 of the separator 4 may be sealed by perforating the separator 4 on both sides through the holes 21 and welding the separators 4 on both sides through the holes 21.

Further, in the description of the above embodiment, the example of the positive electrode plate 2 having a rectangular shape and the lead portion 2a formed so as to protrude over substantially the entire length of one side portion has been described. However, as shown in FIG. The positive electrode plate 22 formed by seam welding a lead plate 23 formed by projecting a lead portion 23a extending upward to a non-coated portion 22a of the active material formed on an upper edge portion thereof also has an active portion from the lower side. A bag-shaped separator 24 is placed so as to cover substantially the entire surface of the material application portion, and a portion of the opening 25 except for the lead portion 23a is sealed with a welding seal 26, and a portion corresponding to the lead portion 23a is an adhesive. 2
The same operation and effect can be achieved by bonding and sealing at step 7.

Further, as shown in FIG.
Are formed in the lead portion 23a at appropriate intervals by drilling holes 28 (for example, holes having a diameter of 1 mm at a pitch of 5 mm), and welding the separators 24 on both sides through the holes 28. May be sealed.

Further, in the above description of the embodiment, an example in which the positive electrodes 2 and 22 are covered with the separators 4 and 24 has been described.
It goes without saying that a separator may be placed on the negative electrode plate side in some cases.

[0023]

According to the battery electrode group of the present invention, as is apparent from the above description, the entire periphery of the bag-shaped separator is sealed, so that the inside of the bag-shaped separator is It is possible to eliminate the possibility that short-circuiting will not occur due to no foreign matter entering the device, and also prevent the active material peeled off from the electrode plate from scattering and contaminating the equipment.

[Brief description of the drawings]

1A and 1B show an electrode group according to an embodiment of the present invention, wherein FIG. 1A is a perspective view, and FIG. 1B is a cross-sectional plan view taken along line AA of FIG.

FIG. 2 is a front view of a positive electrode plate covered with a separator of the same embodiment.

FIG. 3 is a front view showing a short-circuit inspection state of the electrode group in the embodiment.

FIG. 4 is a front view of another configuration example of the positive electrode plate covered with the separator of the embodiment.

FIG. 5 is a front view of a positive electrode plate covered with a separator according to another embodiment of the present invention.

FIG. 6 is a front view of another configuration example of the positive electrode plate covered with the separator of the embodiment.

7A and 7B show a positive electrode plate covered with a separator in a conventional electrode plate group, wherein FIG. 7A is a front view of one configuration example, and FIG. 7B is a front view of another configuration example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode group 2 Positive electrode plate 2a Lead part 3 Negative electrode plate 3a Lead part 4 Separator 9 Welding seal 10 Opening 11 Adhesive 21 Hole 22 Positive electrode 23a Leading part 24 Separator 25 Opening 26 Welding seal 27 Adhesive 28 hole

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masato Onishi 555 Sakaijuku, Kosai-shi, Shizuoka Prefecture Inside Panasonic EV Energy Corporation (72) Inventor Shinsuke Fukuda 555 Sakaijuku, Kosai-shi, Shizuoka Prefecture Inside Panasonic EV Energy Corporation ( 72) Inventor Mitsugu Takagi 555 Sakaijuku, Kosai-shi, Shizuoka Prefecture F-term in Panasonic EV Energy Co., Ltd. (reference) 5H024 BB14 CC06 CC17 DD09 DD11 DD14 HH15 5H028 AA05 BB05 CC07 CC11

Claims (4)

[Claims] 1. A negative electrode plate and a positive electrode plate are alternately laminated with at least one of the negative electrode plate and the positive electrode plate covered with a bag-shaped separator, whereby the negative electrode plate and the positive electrode plate are interposed via the separator. An electrode group of batteries, wherein the entire circumference of the separator is sealed along four sides of the electrode plate. 2. The lead portion of the electrode plate and its periphery except for the vicinity thereof are sealed by fusion sealing the separator, and the separator is bonded and sealed at the lead portion of the electrode plate with an adhesive. An electrode group of the battery according to 1. 3. The separator is melt-sealed around the lead portion of the electrode plate and its periphery except for the vicinity thereof, and at the lead portion of the electrode plate, the separator is melt-sealed through a hole formed in the lead portion. The electrode plate group of the battery according to claim 1. 4. A negative electrode plate and a positive electrode plate are alternately laminated with at least one of the negative electrode plate and the positive electrode plate covered with a bag-shaped separator, so that the negative electrode plate and the positive electrode plate are interposed through the separator. An electrode group of a battery, wherein at least a part of a side having a lead portion of an electrode plate of a separator is sealed along four sides of the electrode plate.