JP3114077B2 - Flat 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 flat battery having improved electrical contact between a positive electrode mixture and a positive electrode container.

[0002]

2. Description of the Related Art Conventionally, various studies have been made on the conductive structure between a positive electrode mixture and a positive electrode container in order to stabilize the voltage during discharge of a battery and maintain the stability of the internal resistance. Conventionally, the following structure has been used to maintain good contact between the positive electrode mixture and the positive electrode container.

(1) On the surface of the positive electrode container which is in contact with the positive electrode mixture,
Apply conductive paint. Alternatively, a structure in which a metal net, expanded metal, or the like is welded. (2) A structure in which a conductive paint is applied to the inside of the L-shaped bottom surface of the metal ring having an L-shaped cross section, that is, the portion in contact with the flat portion of the positive electrode mixture to form a positive electrode current collector. (3) An undulation having the same height is provided on the bottom surface of the positive electrode ring having a cross section filled with the positive electrode mixture and having an L-shape, and the tip of the undulation is so formed as to be flush with the bottom flat surface of the positive electrode ring. There has been proposed a structure in which the inner bottom surface is brought into pressure contact with the inner surface.

[0004]

The structure of the above (1) is as follows.
The contact between the positive electrode container and the positive electrode mixture becomes good. However, when welding a metal net, expanded metal, or the like, a step of punching or cutting the metal net or expanded metal, a step of washing and removing the oil used at this time,
And a step of welding the current collector to the positive electrode container. In addition, costs for metal nets, expanded metal, and the like are required. In the case of (2), the step of applying the conductive paint and the cost of the conductive paint are required.

In the case of (3), (1), (2)
This is a solution to the above problem, but has the following problems.
When supplying parts, a parts feeder is generally used.However, since the undulating tip moves while contacting the parts feeder, the tip is dirty, and contaminants exist between the tip and the positive electrode container even after being supplied into the battery. Also, there is a problem that contact resistance occurs even after assembly, and the internal resistance of the battery increases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a flat battery having good electrical contact between a positive electrode ring and a positive electrode container and having excellent discharge performance.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a battery in which a positive electrode ring having an L-shaped cross section is disposed between a positive electrode mixture and a positive electrode container. A flat battery having low undulations, wherein undulations having different heights are brought into pressure contact with the inner bottom surface of the positive electrode container so that the bottom plane of the positive electrode ring and the tip of the undulations are flush with each other. It is.

[0008]

According to the present invention, the undulations of different heights are provided on the positive electrode ring. When the bottom of the ring flows while contacting the parts feeder, even if the tip of the high undulations is in contact with the parts feeder, the tip of the low undulation is provided. The part does not touch the parts feeder. For this reason, even if the tip part having a high undulation comes into contact with the parts feeder and becomes dirty, the tip part having a low undulation is not stained.

[0009] Since there is such a clean undulation tip, the undulation tips having different heights are brought into pressure contact with the inner bottom surface of the positive electrode container so as to be flush with the positive electrode ring garden plane. Can be. For this reason, there is a contact portion between the clean tip of the undulation and the bottom surface of the positive electrode container, and stable contact with low resistance can always be obtained.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an outer diameter of 20.0 mm and a thickness of 3.2.
1 shows a lithium manganese dioxide flat organic electrolyte battery having a thickness of 1 mm. 1, reference numeral 1 denotes a stainless steel positive electrode container also serving as a positive electrode terminal, 2 denotes a negative electrode sealing plate also serving as a negative electrode terminal also made of stainless steel, and 3 denotes lithium, which is a negative electrode active material. ing. Reference numeral 4 denotes a positive electrode mixture composed of a mixture of manganese dioxide, a conductive material and a binder. 5 is a separator made of polypropylene, 6 is a polypropylene gasket, and 7 is a positive electrode ring filled with a positive electrode mixture. In FIG. 2, 8 of the positive electrode ring 7 is a high undulation, and 9 is a low undulation.

As shown in FIG. 5, when the positive electrode mixture 4 is filled into the positive electrode ring 7 having an L-shaped cross section, the undulations 8 and 9 are suitable for the large-diameter concave portion 31 and the small-diameter concave portion 32 in the lower punch 30 as shown in FIG. By providing several, undulations having different heights are formed on the bottom surface of the positive electrode ring after filling. The positive electrode ring 7 is as shown in FIG.
At the time of assembling the battery, it is pressed by the sealing plate 2 so that the tips of the undulations 8 and 9 are in pressure contact with the bottom surface of the positive electrode container 1 so as to be flush. Reference numeral 10 denotes dirt attached to the tip of the high protrusion 8. The electrolyte is used by dissolving lithium perchlorate in a mixture of propylene carbonate and 1,2-dimethoxyethane.

The assembly as described above is referred to as the flat organic electrolyte battery according to the present invention.
The same type of battery in which the undulations 18 having the same height and to which dirt 20 is attached is provided on the bottom surface of the conventional battery. The internal resistance of the undischarged batteries of these batteries was measured, and the results are shown in Table 1. The battery of the present invention has extremely low internal resistance, whereas the conventional battery has high internal resistance.

[0013]

[Table 1]

FIG. 6 shows that 500 Ω-10 msec,
The width of a discharge curve obtained by performing a continuous pulse test of 2.2 MΩ-90 msec at a temperature of 0 ° C. is shown. A is a battery according to the present invention, B is a battery having a high internal resistance of a conventional undischarged battery, and C is a battery having a low internal resistance of a conventional undischarged battery. The battery A of the present invention and the conventional example C exhibited a stable operating voltage until the end of discharge, whereas the conventional example B had a low operating voltage during the discharge, and the duration of the battery A of the present invention was low.
And the result was shorter than the conventional battery C.

In order to clarify the cause, a battery was disassembled and investigated. Table 2 shows the observation results.

[0016]

[Table 2]

According to the results, the battery using the positive electrode ring having a dirty top and bottom has a high internal resistance, and the continuous pulse test has a short duration. It turns out that there is a cause of increasing the resistance. Also, the reason why the variation of the discharge voltage did not occur in the battery A of the present invention is that the tip of the lower undulation was not contaminated by the parts feeder at all,
After the battery was assembled, the positive electrode container was in good contact with the tip of the lower undulation, so that the internal resistance was low, the variation was extremely small, and the result was stable.

[0018]

As described above, a high-level undulation and a low-level undulation are provided on the positive electrode ring having an L-shaped cross section, and the undulation tip is pressed on the inner bottom surface of the positive electrode case, and is flush with the bottom surface of the positive electrode ring. With such a structure, a flat battery with extremely stable discharge performance can be supplied while reducing component costs and man-hours.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a flat organic electrolyte battery using a positive electrode ring having high undulations and low undulations according to the present invention.

FIG. 2 is a perspective view of a positive electrode ring of the present invention.

FIG. 3 is a cross-sectional view of a conventional flat battery of the same type using a conventional positive electrode ring provided with undulations at the same height.

FIG. 4 is a perspective view of a conventional positive electrode ring.

FIG. 5 is a front view of a press-contact receiving surface of the mixture-filled lower punch.

FIG. 6 shows a battery A of the present invention, a conventional battery B having an internal resistance of 20 Ω or more, and a conventional battery C having an internal resistance of 10 Ω or less, at 500 ° C.-10 msec and 2.2 MΩ-9 at a temperature of 0 ° C.
FIG. 4 is a comparison diagram of a discharge voltage width of a pulse discharge of 0 msec.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Positive electrode container 4 ... Positive electrode mixture 7 ... Positive electrode ring 8 ... High undulation 9 ... Low undulation 10,20 ... Dirt 18 ... Elevation at the same height

Claims (1)

(57) [Claims] 1. A cross section of L between a positive electrode mixture and a positive electrode container
A battery in which a U-shaped positive electrode ring is disposed, wherein a high undulation and a low undulation are provided on a bottom plane of the positive electrode ring, and the tip of the undulation is brought into pressure contact with the inner bottom surface of the positive electrode container. Flat battery.