JP3301802B2 - Battery - 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 using a spiral electrode body having a non-circular cross section.

[0002]

2. Description of the Related Art Conventionally, the digitization of many devices has progressed, and batteries have been used as power sources for these devices. Among such devices, particularly in the fields of radios, tape recorders, cameras and the like, there is a demand for miniaturization and thinning of the devices. Considering the miniaturization and thinning of the device,
Naturally, batteries are expected to be smaller and lighter. Furthermore, considering the ratio of the battery volume in the device (volume efficiency in the device), the cylindrical battery has a large space loss and the power supply can be downsized. It is known that a rectangular type battery or the like is advantageous in terms of mounting efficiency because it is disadvantageous for increasing the capacity.

As this prismatic type battery, a stacked type in which electrode plates are stacked in several layers is widely used in the fields of nickel-cadmium batteries, lead batteries and the like. However, when high current and high voltage are required in the equipment used, and in consideration of further increasing the output and improving the heavy load characteristics, the electrodes are thinned and spirally wound to form a spiral electrode body. Is most effective, and is also advantageous in terms of productivity.

When a spiral electrode body is inserted into such a rectangular battery, the spiral electrode body cannot be inserted into a battery outer can unless the spiral electrode body is formed in a non-circular shape.

As a method of manufacturing this non-circular spiral electrode body, a method of winding an electrode plate around a plate-shaped core (JP-A-58-218768) is known. Forming by pressing in a predetermined direction
163965, JP-A-60-25164).

However, in the method (1), since the winding is performed in an elliptical shape from the beginning, the winding becomes difficult due to the effect of a large change in the supply speed of the electrode plate during winding. There is a problem that it becomes complicated. Therefore,
The method of winding and pressing to a perfect circle is often used.

However, according to this method, when the perfectly circular spiral electrode body 13 shown in FIG. 7 is pressed in a predetermined direction as shown in FIG. 8 to form the non-circular spiral electrode body 2b,
Central through-hole 6 of spiral electrode body formed at the time of winding a perfect circle
Indicates an irregular deformation. This deformation is illustrated in FIG.
As shown in the hatched area, the electrodes in the long side direction of the spiral electrode body are curved, the distance between the electrodes is greatly widened, the degree of tightness between the electrodes cannot be maintained uniformly, and the discharge characteristics and the cycle characteristics are deteriorated. Had a negative effect. Further, the electrode in the vicinity of the innermost peripheral portion of the spiral electrode body is bent at the maximum curvature, so that the active material is separated from the electrode core or the electrode is damaged. Further, in an extreme case, the damaged electrode may break the separator and cause an internal short circuit.

As a countermeasure for this, after inserting a core having a desired cross-sectional shape into the central through hole of the perfect circular spiral electrode body,
Method for compression-molding a spiral electrode body (Japanese Patent Application Laid-Open No. 60-2516)
No. 4) has been proposed.

However, the purpose of this publication is to secure a spot hole. For this purpose, the core must be removed after inserting the spiral electrode body into the outer can. As a result, there is a problem that the degree of tension of the spiral electrode body cannot be secured.

Furthermore, this method cannot sufficiently prevent the electrode innermost part of the spiral electrode body from being damaged and the degree of tightness being non-uniform.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a battery having a spiral electrode body having a non-circular cross section such as an ellipse or an ellipse. An object of the present invention is to provide a high-quality, high-performance battery by preventing battery performance deterioration or the like caused by damage to the electrode of the spiral electrode body, internal short circuit, or unevenness in the degree of tightness of the electrode.

[0012]

According to the present invention, a positive electrode, a negative electrode, and a separator located between these two electrodes are wound to form a perfect circular spiral electrode body. In a battery having a non-circular spiral electrode body obtained by pressing, an elastic spring member is disposed in a central through-hole of the non-circular spiral electrode body.

Preferably, the elastic spring member has a substantially U shape.

Further, it is preferable that a cross-sectional shape of the outer can housing the non-circular spiral electrode body has a rectangular or elliptical shape.

[0015]

According to the present invention, since the elastic spring member is disposed in the central through-hole of the spiral electrode body, when the perfect circular spiral electrode body is formed into a non-circular shape by pressing, the elastic spring member is provided. Since the elastic force acts in the long side direction of the non-circular spiral electrode body,
It is possible to prevent a tensile load from being applied to the straight portion in the long side direction and to bend outward.

Therefore, even if a non-circular spiral electrode body is formed, the degree of tightness between the electrode plates does not decrease, and internal short-circuiting due to damage to the electrode and lack of the electrode can be prevented.

In addition, since the stress in the inner peripheral portion is prevented from being deformed and the uniform stress is maintained, the battery reaction is promoted, and the discharge characteristics and the cycle characteristics in the case of a secondary battery are improved.

[0018]

【Example】

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

FIG. 1 shows a battery having the non-circular spiral electrode body of the present invention. Reference numeral 1 denotes an elastic spring member disposed in the central through-hole 6 of the non-circular spiral electrode body 2a. Reference numeral 2a denotes a positive electrode 3, a negative electrode 4, and a separator 5 located between these two electrodes.
And a non-circular spiral electrode body wound with. The non-circular spiral electrode body 2a is inserted into a battery outer can 7 having conductivity. Battery outer can 7 and positive electrode 3 are electrically connected. Next, an electrolytic solution is injected, and the negative electrode lead 8 is connected to the negative electrode terminal 9. The negative electrode terminal 9 is fixed to the sealing plate 11 via an insulating packing 10 by caulking in a central through hole of the sealing plate. The sealing plate 11 and the open end of the battery outer can 7 are hermetically sealed by laser welding.

In the embodiment, the positive electrode 3 is the outermost periphery and is in contact with the battery outer can 7, but the cathode 3 and the negative electrode 4 in the embodiment are reversed, and the negative electrode 4 is the outermost periphery.
May be contacted.

FIG. 2 is a sectional view of a non-circular spiral electrode body according to the present invention.

FIG. 3 is a side view of the elastic spring member 1 provided in the central through hole 6 of the non-circular spiral electrode body 2a. As the elastic spring member 1, when the non-circular spiral electrode body 2a is inserted into the non-circular battery outer can 7, a form in which a tensile load can be applied in the long side direction, particularly FIG. The substantially U-shaped configuration shown is suitable.

FIG. 4 shows a manufacturing process of the non-circular spiral electrode body 2a. According to the following steps, a non-circular spiral electrode body is manufactured. The elastic spring member 1 is inserted into the hollow portion of the core 12 (FIG. 4A). The positive electrode 3 and the negative electrode 4 are wound around a winding core 12 with a separator 5 interposed therebetween to produce a perfect circular spiral electrode body 13 (FIG. 4B). After winding on the perfect spiral electrode body 13, the winding core 12 is pulled out from the perfect spiral electrode body 13 (FIG. 4c). The non-circular spiral electrode body 2a is manufactured by applying pressure to the perfect circular spiral electrode body 13 from a predetermined direction (FIG. 4D). Here, the elastic spring member 1 is disposed so that the elastic direction of the elastic spring member 1 is applied to the long side direction of the non-circular spiral electrode body 2a.

In the above-described manufacturing process, the elastic spring member 1 is inserted into the core 12 in advance, but the electrode is wound around the core 12 without first inserting anything into the hollow portion of the core 12. After that, the elastic spring member 1 may be inserted into the hollow portion of the core 12.

The battery having the non-circular spiral electrode body 2a obtained as described above is referred to as Battery A1 of the present invention.

[Comparative Example] As a comparative example, a perfect circular spiral electrode body 1 in which nothing is inserted in the central through hole 6 shown in FIG.
Comparative battery X1 was manufactured in the same manner as the battery of the present invention, except that pressure was applied to the sample No. 3 from a predetermined direction, and the non-circular spiral electrode body 2b shown in FIG. 8 was used.

[Load characteristics] Battery A1 of the present invention and comparative battery X
1 was measured, and the results are shown in FIG. The measurement conditions are such that each battery is charged to a charge end voltage of 4.2 V at a charge current of 200 mA, and then discharged to a discharge end voltage of 2.75 V at a discharge current of 400 mA.

FIG. 5 shows that the battery A1 of the present invention has a higher battery voltage and a longer discharge time than the comparative battery X1.

[Cycle Characteristics] The cycle characteristics of the battery A1 of the present invention and the comparative battery X1 were measured, and the results are shown in FIG. The measurement conditions are such that an operation of charging each battery to a charge end voltage of 4.2 V at a charge current of 100 mA and then discharging to a discharge end voltage of 2.75 at a discharge current of 100 mA is repeatedly performed.

FIG. 6 shows that the battery A1 of the present invention has a longer cycle life and a higher capacity retention ratio than the comparative battery X1.

From the above results, in the battery A1 of the present invention, since the elastic spring member is disposed in the central through-hole of the non-circular spiral electrode body, the non-circular shape is formed by the elastic force of the elastic spring member. It is possible to prevent a decrease in the degree of tightness between the electrode plates of the spiral electrode body, prevent peeling of the active material from the core of the electrode and damage of the electrode, and improve cycle characteristics and the like.

[0032]

According to the present invention, since the elastic spring member is disposed in the central through-hole of the non-circular spiral electrode body, even if the spiral electrode body is pressed into a non-circular shape, the space between the electrodes is reduced. Since the degree of tension can be ensured and the electrode can be prevented from peeling or falling off, cycle characteristics and load characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a battery of the present invention.

FIG. 2 is a sectional view of a non-circular spiral electrode body of the battery of the present invention.

FIG. 3 is a side view of an elastic spring member.

FIG. 4 is a manufacturing process diagram of the battery of the present invention.

FIG. 5 is a load characteristic diagram of the battery of the present invention and a comparative battery.

FIG. 6 is a cycle characteristic diagram of the battery of the present invention and a comparative battery.

FIG. 7 is a cross-sectional view of a conventional perfect circular spiral electrode body.

FIG. 8 is a sectional view of a conventional non-circular spiral electrode body.

[Explanation of symbols]

 1 ... Elastic spring member 2a ... Non-circular spiral electrode body of the present invention 2b ... Conventional non-circular spiral electrode body 3 ... Positive electrode 4 ... Negative electrode 5... Separator 6... Central through hole 7... Battery outer can 8... Negative electrode lead 9. ··· Negative electrode terminal 10 ····· Insulating packing 11 ······································ Circular spiral electrode body A1 ···· Battery X1 of the present invention ..... Comparative battery

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 10/04 H01M 10/28

Claims (3)

(57) [Claims] 1. A non-circular electrode obtained by winding a positive electrode, a negative electrode, and a separator located between these two electrodes to form a perfect circular spiral electrode body, and then pressing the perfect circular spiral electrode body. A battery having a spiral shaped electrode body, wherein an elastic spring member is disposed in a central through-hole of the non-circular spiral shaped electrode body. 2. The battery according to claim 1, wherein the elastic spring member has a substantially U shape. 3. The battery according to claim 1, wherein the cross-sectional shape of the outer can housing the non-circular spiral electrode body has a rectangular shape or an oval shape.