JP3407973B2 - Battery with spiral electrode body - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery provided with a spiral electrode body, and more particularly to a core of the spiral electrode body.

[0002]

2. Description of the Related Art Conventionally, in a battery provided with a spiral electrode body, the current is collected by welding a tab taken out from the positive or negative electrode or a lead portion separately welded to a core body to a battery outer can or a sealing body, The outermost electrode portion of the spirally wound electrode body was brought into direct contact with the battery outer can to collect current.

However, when the tab portion or the lead portion is welded, there is a problem in that the tab portion or the lead portion comes into contact with the electrode body due to bending or the like to cause an internal short circuit.
In order to solve this, it is necessary to take measures such as inserting an insulating plate or the like on the upper part of the electrode body or adding an inspection process, which causes a problem that the working process becomes complicated.

Further, Japanese Utility Model Publication No. 56-150068,
Japanese Utility Model Application Laid-Open No. 59-61468 discloses collecting a current by contacting or spot welding a metal rod also serving as a winding core to a sealing body.

However, in this case, the other electrode, which does not collect current with the metal rod, has the same problem as described above.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and can reliably collect current from the electrode body, simplify the manufacturing process, and reliably prevent internal short-circuiting. Is.

[0007]

A battery provided with a spirally wound electrode body of the present invention is a battery in which a spirally wound electrode body in which a positive electrode and a negative electrode are wound around a core via a separator is housed in a battery case, The center of the winding core is made of an insulating member having elasticity and both ends of the winding core are made of electrically conductive metal members, and each of the metal members is electrically connected to the positive electrode and the negative electrode. Further, each of the metal members is pressure-contacted with and electrically connected to the positive electrode terminal and the negative electrode terminal of the battery case.

It is preferable that the insulating member is a thermoplastic member.

Further, it is preferable that the thermoplastic member is made of polypropylene.

[0010]

According to the present invention, the winding core, which is composed of an insulating member having a central portion having elasticity, is used for collecting current in the spiral electrode body.
The current collection to the positive electrode terminal and the negative electrode terminal in the battery case is pressed against the metal members at both ends of the winding core by the elastic force of the insulating member, so that the tab or the lead portion is unnecessary.

Therefore, the present invention can prevent the risk of internal short circuit and the like caused by using the tab and the lead portion.

Further, according to the present invention, the step of inspecting the internal short circuit is eliminated, and the rationalization is achieved, so that the productivity is improved.

When the battery heats up due to an external short circuit or overcharge, the insulating member at the center of the winding core is made of a thermoplastic material. It significantly decreases, current collection becomes poor, and short-circuit current can be interrupted (Fig. 2).

[0014]

【Example】

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of the main part of a battery provided with the spirally wound electrode body of the present invention. 1 is a sheet-shaped positive electrode of manganese dioxide mixture, and a negative electrode using a lithium metal foil,
The spirally wound electrode body is wound around the winding core 2 via a polypropylene microporous membrane separator.

Reference numeral 3 denotes a positive electrode current collector rod made of a metallic member made of stainless steel, and 5 denotes a negative electrode current collector rod made of a metallic member made of nickel. Both the positive electrode current collector rod 3 and the negative electrode current collector rod 5 are electrically connected to the positive electrode and the negative electrode, respectively.

The winding core 2 is formed of a polypropylene insulating member 4 at the center of the current collecting rods 3 and 5, and has a diameter of 4 mm.
Is. The battery case 6 is composed of a battery outer can 7 and a sealing plate 8. The spiral electrode body 1 is inserted inside the battery outer can 7. After the electrolytic solution is injected, the battery case 6 is insulated and packed in the opening of the battery outer can. A sealing plate 7 equipped with a safety device is arranged via 9 and is fixed by caulking.

In this state, the elastic force of the insulating member 4 in the central portion of the winding core 2 causes the current collector 3 to press the positive electrode to the sealing body 8 which also serves as the positive electrode terminal, and the negative electrode to collect the negative electrode by the current collector 5. Current is pressure-contacted and collected on the battery outer can 7 that also serves as a terminal. The battery thus manufactured is referred to as Battery A of the invention.

[Comparative Example 1] FIG. 3 shows a cross-sectional view of a main part of Comparative Example 1. Reference numeral 21 denotes a spirally wound electrode body having a sheet-shaped positive electrode made of a manganese dioxide mixture and a negative electrode made of a lithium metal foil with a separator made of a polypropylene microporous film interposed.

Reference numeral 23 is a stainless steel tab for collecting current attached to the positive electrode core, and 25 is a nickel tab for collecting current attached to the negative electrode core. The stainless steel tab 23 is the sealing body 7.
Further, the nickel tabs 25 are spot-welded to the outer cans 6, respectively, to collect current.

Thereafter, a battery was prepared in the same manner as in Example 1, and this battery was designated as comparative battery X1.

[Comparative Example 2] FIG. 4 shows a cross-sectional view of essential parts of Comparative Example 2. Reference numeral 31 was wound around a negative electrode current collector core 33 with a separator made of polypropylene microporous film between a positive electrode formed of a sheet of manganese dioxide mixture and a negative electrode formed of a lithium metal foil. It is a spiral electrode body.

The negative electrode current collecting core 33 is spot-welded to the sealing body 7 to collect current. In the method of collecting the positive electrode, the positive electrode in the outermost peripheral portion of the spirally wound electrode body is brought into direct contact with the battery outer can to collect the current.

Hereinafter, a battery was prepared in the same manner as in Example 1, and this battery was designated as comparative battery X2.

[Experiment 1] Battery A of the present invention and comparative batteries X1 and X2 were respectively placed on concrete from a height of 1 m.
Table 1 shows the rate of occurrence of internal short circuit in the battery after it was naturally dropped 0 times.
It was shown to. The number of batteries tested was 10 each.

[0026]

[Table 1]

From Table 1, it is considered that the battery A of the present invention has a small movement of the electrode group due to a drop impact and no positive and negative electrode tabs, so that the occurrence rate of the internal short circuit due to the contact between the tab and the electrode group is low. .

[Experiment 2] Next, an experiment was conducted in which the battery A of the present invention and the comparative batteries X1 and X2 were externally short-circuited. In this experiment, a battery in which the short circuit current cannot be interrupted in a short time and the battery external temperature rises was determined to be a defective battery, and the occurrence rate of this defective battery was expressed as a battery defective rate. The results are shown in Table 2.
The number of batteries tested was 10 each.

[0029]

[Table 2]

It can be seen from Table 2 that the battery A of the present invention has a low battery defect rate even when an external short circuit occurs.

FIG. 5 shows the relationship between the short circuit current and the battery external temperature of the battery A of the present invention and the comparative batteries X1 and X2 during the external short circuit time.

As can be seen from FIG. 5, the battery A of the present invention is
It can be seen that when the battery external temperature reaches about 120 ° C., the short circuit current sharply decreases. As shown in FIG. 2, when the temperature rises, thermal deformation of the polypropylene insulating member 4 used in the central portion of the winding core 2 causes
It is considered that the elastic force of pressing the sealing body 8 and the battery outer can 7 is lost, the core cannot contact, the current collection becomes defective and the short circuit current does not flow, and the temperature rise is suppressed. .

[0033]

According to the present invention, the repulsive force of the elastic insulating member provided at the center of the winding core can collect current from the electrode portion of the spirally wound electrode body to the sealing body and the battery outer can. Since the process is simplified and the current collecting tabs or leads are not used, it is possible to prevent an internal short circuit due to the tabs and the electrode body, and a temperature rise occurs due to an abnormality such as an external short circuit. In this case, the insulating member is thermally deformed, the elastic force is lost and the current collecting effect is reduced, so that the flow of current can be interrupted, and the safety is improved without danger of ignition of the battery.

The present invention is effective in a battery provided with a spiral electrode body regardless of the primary battery and the secondary battery.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a battery A of the invention.

FIG. 2 is a cross-sectional view of a main part of the battery A of the present invention when an external short circuit occurs.

FIG. 3 is a cross-sectional view of a main part of a comparative battery X1.

FIG. 4 is a sectional view of a main part of a comparative battery X2.

FIG. 5 is a diagram showing a relationship among a short circuit time, a battery external temperature, and a short circuit current.

[Explanation of symbols]

1,21,31 ... Swirl electrode body 2 ... 3 ・ ・ ・ ・ ・ ・ ・ ・ Positive collector rod (metal member) 4 Insulation member 5 ... Negative electrode collector rod (metal member) 6 ... Battery case A: Battery of the present invention X1, X2 ... Comparison battery

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01M 6/02 H01M 10/04 H01M 2/26 H01M 2/34

Claims (3)

(57) [Claims] 1. A battery in which a spirally wound electrode body, in which a positive electrode and a negative electrode are wound around a winding core via a separator, is housed in a battery case, wherein the winding core is made of an insulating member having elasticity. Both ends are made of an electrically conductive metal member, each metal member is electrically connected to the positive electrode and the negative electrode, respectively, and each metal member,
A battery provided with a spiral electrode body, which is press-contacted with and electrically connected to a positive electrode terminal and a negative electrode terminal of a battery case. 2. The battery provided with the spiral electrode body according to claim 1, wherein the insulating member is a thermoplastic member. 3. The battery provided with the spiral electrode body according to claim 2, wherein the thermoplastic member is made of polypropylene.