JPH0714560U - Flat type non-aqueous electrolyte battery - Google Patents

Abstract

(57) [Summary] [Object] To provide a flat non-aqueous electrolyte battery capable of maintaining a stable discharge state until the end of discharge and preventing a decrease in the total battery height. A positive electrode mixture 6, a separator 8 and a negative electrode active material 10 are stacked in a flat positive electrode can 2 in the presence of a non-aqueous electrolyte, and the opening of the positive electrode can 2 is sealed by a negative electrode can 14. To form a flat type non-aqueous electrolyte battery. A positive electrode ring 4 is provided in the positive electrode can 2, and a negative electrode active material 10 arranged above and a positive electrode mixture 6 for carrying out a battery reaction are accommodated therein. The ring body 20 has a collar portion 20a that is locked to the top portion of the positive electrode mixture 6 at its upper portion, and is attached to the positive electrode ring 4 slidably in the vertical direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a battery using a non-aqueous electrolyte, and more particularly to a flat type lithium battery such as a coin type or a button type.

[0002]

[Prior art]

 In recent years, various lithium batteries using lithium as a negative electrode active material have been put into practical use. Lithium batteries use non-aqueous organic electrolytes because lithium reacts violently with water. Since this non-aqueous electrolyte does not directly participate in the battery reaction, the electrolyte layer can be thinned, and it is possible to manufacture a battery having a flat shape. This flat type non-aqueous electrolyte battery is economical, highly safe, and free from pollution, in addition to the reasons that it can be downsized, high electromotive force can be obtained, and it has a long shelf life. For this reason, it is very often used in small electronic devices that operate with a small current. Therefore, there is a demand for a high performance flat non-aqueous electrolyte battery that has a longer duration and can obtain a stable electromotive force.

FIG. 6 is a longitudinal sectional view showing a state of a conventional flat type non-aqueous electrolyte battery before discharge. The configuration of this flat non-aqueous electrolyte battery will be described. A positive electrode ring 4 is fixed on the inner bottom surface of the flat positive electrode can 2. A positive electrode mixture 6 is housed in the positive electrode ring 4, a separator 8 and a negative electrode active material 10 are sequentially stacked on the positive electrode mixture 6, and the positive electrode can 2 is sealed by a negative electrode can 14 via a gasket 12. Has been done. In the non-aqueous electrolyte battery using lithium as the negative electrode active material, the negative electrode active material 10 gradually diffuses to the positive electrode mixture 6 side through the separator 8 in the course of discharge, and therefore, The positive electrode mixture 6 expands.

[0004]

[Problems to be solved by the device]

 Inside the flat non-aqueous electrolyte battery 16 shown in FIG. 6, there is a space 15 defined by the outer peripheral surface of the negative electrode active material 10 and the inner surface of the negative electrode can 14. As described above, the negative electrode active material 10 contracts in the process of discharging, and the positive electrode mixture 6 expands so as to fill the contracted portion. Then, the positive electrode mixture 6 also expands inside the space 15.

Since the separator 8 is disposed between the negative electrode active material 10 and the positive electrode mixture 6, the separator 8 is pushed upward by the expansion of the positive electrode mixture 6 and moves toward the negative electrode can 14. Therefore, as shown in FIG. 7, a void 7 is generated between the separator 8 and the positive electrode ring 4. In some cases, the positive electrode mixture 6 that projects into the void 7 is missing due to its own weight or vibration from the outside.

At the end of discharge, the negative electrode active material 10 of the battery 16 is consumed and almost disappears, so that the separator 8 approaches the negative electrode can 14 and almost contacts the inner surface thereof. As shown in FIG. 8, the positive electrode mixture 6a missing in the void 7 is accumulated in the groove between the gasket 12 and the positive electrode ring 4 as the missing positive electrode agent 6a. Since such a missing positive electrode mixture 6 does not participate in the subsequent battery reaction at all, the utilization rate of the positive electrode mixture 6 is reduced, and the discharge duration is shortened.

In addition, the negative electrode can 14, the negative electrode active material 10, the separator 8, the positive electrode mixture 6, and the positive electrode can 2 are closely adhered to each other during the manufacturing process so that the battery reaction during discharge smoothly proceeds. However, since the expansion of the positive electrode mixture 6 extends to the space 15 as described above, the close contact state thereof deteriorates with discharge. Then, the increase of the internal resistance and the accompanying decrease of the battery voltage at the end of discharge become remarkable. In addition, the internal resistance increases battery heat generation, which may affect external devices, and leads to capacity loss of the battery itself. This causes variations in battery performance among products.

Furthermore, since the positive electrode mixture 6 expands not only in the thickness direction of the battery 16 but also in the radial direction inward of the voids 7, the thickness of the negative electrode active material 10 increases in the positive electrode mixture 6. However, the total thickness of the positive electrode mixture 6 and the negative electrode active material 10 is reduced. Along with this, the central portion of the negative electrode can 14 is dented, the total height of the battery is reduced, and the contact with the device side terminal to which the battery 16 is applied may be deteriorated.

The present invention has been made in view of the above circumstances, and an object thereof is a flat type that can maintain a stable discharge state until the end of discharge as compared with the related art, and at the same time can prevent a decrease in the total battery height. It is to provide a non-aqueous electrolyte battery.

[0010]

[Means for Solving the Problems]

 In order to achieve the above object, the flat type non-aqueous electrolyte battery according to the present invention has a flat positive electrode can in which a positive electrode mixture, a separator, and a negative electrode active material are accumulated in the presence of the non-aqueous electrolytic solution. A flat non-aqueous electrolyte battery in which the opening of the positive electrode can is layered and sealed by a negative electrode can via a gasket, and a cylindrical positive electrode ring provided in the positive electrode can and containing the positive electrode mixture. A tubular body longer than the vertical expansion length of the positive electrode mixture due to the reaction with the negative electrode active material, and having a flange portion at the top thereof that is locked to the top of the positive electrode mixture. A ring body that is slidably attached to the positive electrode ring in the vertical direction.

[0011]

[Action]

 The operation of the present invention will be described. The flange formed by the reaction with the negative electrode active material is formed in a tubular shape longer than the upward and downward expansion length of the positive electrode mixture, and the collar portion locked to the top of the positive electrode mixture is formed. Since it has a ring body that is installed in the upper part and is slidable in the vertical direction with respect to the positive electrode ring, the lower surface of the flange portion is pushed upward by the top of the expanding positive electrode mixture, The ring body that is integral with the part slides upward. Further, since the flange portion of the ring body is formed on the upper portion of the ring body, the tubular portion of the ring body covers the outer periphery of the positive electrode mixture even when the ring body slides upward. Furthermore, even if the expansion of the positive electrode mixture is maximized and the ring body slides up the maximum, the length of this ring body is longer than the vertical expansion length of the positive electrode mixture, so that the tubular part is always positive. It covers the outer periphery of the mixture and does not separate from the positive electrode ring. As a result, the positive electrode mixture does not drop out of the positive electrode ring.

[0012]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a vertical sectional view showing a state before discharge of a CR2450 type flat type non-aqueous electrolyte battery according to the present invention.

In the battery of this embodiment, the positive electrode mixture 6, the separator 8 and the negative electrode active material 10 are stacked in the flat positive electrode can 2 in the presence of the non-aqueous electrolyte, and the positive electrode can 2 has an opening. The part is hermetically sealed by the negative electrode can 14 via the gasket 12.

A cylindrical positive electrode ring 4 is provided in the positive electrode can 2, and a positive electrode mixture 6 is accommodated inside the positive electrode ring 4. Since this positive electrode ring 4 is erected in the flat positive electrode can 2, it has a supporting and reinforcing portion 4a extending along the inner circumference of the lower portion. Further, the positive electrode ring 4 is made of a conductive material and also has a function of reducing the electric resistance between the positive electrode can 2 and the positive electrode mixture 6 which are in contact with each other.

In addition, a ring 20 a having a collar portion 20 a that is locked to the top of the positive electrode mixture 6 in the positive electrode can 2 and is slidably mounted on the positive electrode ring 4 in the vertical direction. A body 20 is provided.

Next, the shape of the ring body 20 will be described. FIG. 4 is a perspective view and a longitudinal sectional view of the ring body 20 shown in FIGS. The ring body 20 of the present embodiment has a cylindrical shape, but this is because the plane cross-sectional shape of the positive electrode ring 4 is circular. Therefore, if the plane cross-sectional shape of the positive electrode ring 4 is another shape such as a square, The plane cross-sectional shape of the ring body 20 may be changed so that the ring body 20 can be fitted correspondingly.

The height H of the ring body 20 is longer than the pre-calculated vertical expansion length of the positive electrode mixture 6 so that the positive electrode mixture 6 does not separate from the positive electrode ring 4 even if the positive electrode mixture 6 expands in the vertical direction. Has been formed. Further, a flange portion 20a is formed at the upper end of the ring body 20 so as to extend along the inner peripheral edge thereof, and the height H of the ring body 20 is lower than the height of the positive electrode ring 4, so that the flange portion 20a is formed. 20 a is locked on the top surface of the positive electrode mixture 6.

Further, since the inner diameter L1 of the ring body 20 is formed to be larger than the outer diameter of the positive electrode ring 4, the ring body 20 is fitted in the positive electrode ring 4 and moves upward and downward on the outer peripheral surface thereof. It can slide freely.

An inwardly protruding width S of the collar portion 20 a is set to a length necessary for being locked to the top surface of the positive electrode mixture 6. However, if the width S is too large, the diameter of the opening R of the ring body 20 becomes small, the contact area between the positive electrode mixture 6 and the negative electrode active material 10 via the separator 8 decreases, and the internal resistance increases. Resulting in. Therefore, the dimension of the overhang width S needs to be limited to a value that does not affect the battery performance.

The collar portion 20a of the present embodiment is provided along the entire inner peripheral edge of the upper portion of the ring body 20 having a flat tubular shape, but the ring portion 20a expands as the positive electrode mixture 6 expands. As long as the body 20 can be locked at its top, it does not necessarily have to be provided on the entire inner peripheral edge. That is, the collar portion 20a may be provided at a part of the inner peripheral edge of the opening of the ring body 20 or at a plurality of portions.

Further, instead of the ring body 20 having the collar portion 20a as in the present embodiment, a cap-shaped member is provided so as to cover the upper surface thereof to form a cap-shaped ring body, and the cap-shaped member has an upper surface. You may use what formed the several hole.

According to the present embodiment having the above-described configuration, the ring body 20 is locked on the top surface of the positive electrode mixture 6 by the collar portion 20a formed on the inner peripheral edge of the upper portion thereof, so that the battery reaction is performed. As the positive electrode mixture 6 expands as the temperature rises, the lower surface of the collar portion 20a is pushed up to the top surface of the positive electrode mixture 6 and the ring body 20 integrally formed with the collar portion 20a moves upward. To do. When the ring body 20 moves upward as the positive electrode mixture 6 expands, the ring body 20 rises so as to surround the outer periphery of the positive electrode ring 4, so that the outer peripheral side wall of the ring body 20 serves as a barrier. The radial expansion of the positive electrode mixture 6 is prevented.

FIG. 2 is a vertical cross-sectional view showing the state of the flat type non-aqueous electrolyte battery shown in FIG. 1 at the final stage of discharge. The expansion of the positive electrode mixture 6 becomes maximum at the end of discharge, and the negative electrode active material 10 is diffused in the positive electrode mixture 6 and almost disappears. Therefore, the separator 8 almost comes into close contact with the inner surface of the negative electrode can 14. However, unlike the conventional case, the ring body 20 is arranged between the separator 8 and the positive electrode ring 4, and the ring body 20 is formed in a cylindrical shape longer than the vertical expansion length of the positive electrode mixture 6. Therefore, the ring body 20 does not separate from the positive electrode ring 4, and its outer peripheral side wall serves as a barrier to prevent the positive electrode mixture 6 from expanding in the radial direction.

FIG. 3 is an enlarged vertical sectional view of a B part in FIG. As described above, since the ring body 20 prevents expansion in the radial direction, a conventional void 7 is not formed between the separator 8 and the positive electrode ring 4, and therefore, the void 7 prevents the positive electrode. The mixture 6 is never missing.

As described in detail above, the radial expansion of the positive electrode mixture 6 is suppressed and the expansion of the positive electrode mixture 6 is directed only in the vertical direction of the battery, so that the discharge reaction proceeds and the negative electrode active material Even if the material 10 diffuses into the positive electrode mixture 6, the decrease can be sufficiently compensated for by the expansion of the positive electrode mixture 6, and the negative electrode can 14, the negative electrode active material 10, the separator 8, the positive electrode mixture 6, A sufficient close contact state is maintained between each of the positive electrode cans 2. For these reasons, the increase in internal resistance accompanying the progress of the discharge reaction is suppressed to a minimum. Not only is it possible to obtain a stable electromotive force until the end of discharge, but the amount of residual energy loss that remains unused in the battery itself is also reduced, increasing the utilization efficiency of power generation materials. However, the discharge operation can be performed for a long time. At the same time, since the lack of the positive electrode mixture 6 is prevented, it is possible to prevent the reduction of the reaction substance due to it, which also increases the utilization efficiency of the reaction substance and enables the discharge operation for a long time. Further, the depression 14a at the center of the negative electrode can 14 or the positive electrode can 2 does not occur, and contact failure with external equipment is less likely to occur.

Next, in order to confirm the effect of the present invention, three types of batteries, a conventional product in which the positive electrode mixture is missing, a conventional product in which the positive electrode mixture is not missing, and the present invention Actually, the discharge characteristic test was carried out. All batteries were of the CR2450 type equivalent to the above-mentioned embodiment of the present invention, and were subjected to a 2.7 kΩ load continuous discharge test at 20 ° C. The test results are shown in FIG.

As shown in the graph of FIG. 5, in the case of the mixture-deficient product, the positive electrode mixture, which is a reactant, is missing during discharging, and the missing amount is completely involved in the subsequent battery reaction. The electromotive force drops sharply in a shorter time than the conventional product. In addition, even with the conventional products that do not lack the mixture, a sufficient adhesion state cannot be obtained within the power generation element at the end of discharge, so the discharge duration is longer than that of the product without the mixture, but a voltage drop occurs. There is considerable variation in the time of occurrence. On the other hand, in the device of the present invention, the positive electrode mixture is not missing and sufficient adhesion is obtained within the power generation element, so the discharge duration becomes longer and the voltage drop There is not much variation in the time of occurrence. As described above, according to the present invention, it was confirmed that the performance of the battery itself can be sufficiently brought out as compared with the conventional product, and thus the battery performance can be improved.

[0028]

[Effect of device]

 As described in detail above, according to the flat type non-aqueous electrolyte battery of the present invention, the flat non-aqueous electrolyte battery is formed into a tubular shape longer than the vertical expansion length of the positive electrode mixture due to the reaction with the negative electrode active material. Since a ring body having a flange portion that is locked to the top of the positive electrode mixture is provided so as to be slidable in the vertical direction with respect to the positive electrode ring, this ring body is It moves upward with expansion and prevents radial expansion of the positive electrode mixture. As a result, the positive electrode mixture is not lost, the utilization efficiency of the reactant is improved, and the discharge characteristics can be improved.

Further, as described above, since the radial expansion of the positive electrode mixture is prevented, the total thickness of the positive electrode mixture and the negative electrode active material does not decrease, and the negative electrode can is dented to reduce the total battery capacity. The height does not decrease. As a result, the contact state with the device side terminal does not deteriorate.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a state before discharge of a flat type non-aqueous electrolyte battery according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a state of a flat type non-aqueous electrolyte battery according to an embodiment of the present invention after discharging.

FIG. 3 is an enlarged vertical sectional view of a B part in FIG.

FIG. 4A is a perspective view showing a ring body of the present invention,
(B) is a vertical cross-sectional view of (a).

FIG. 5 is a graph showing a comparison of discharge characteristics of respective batteries.

FIG. 6 is a vertical cross-sectional view showing a state of a conventional battery before discharging.

FIG. 7 is a vertical cross-sectional view showing a state of a conventional battery at the final stage of discharge.

FIG. 8 is an enlarged vertical sectional view of a portion A of FIG.

[Explanation of symbols]

 4 Positive Electrode Ring 6 Positive Electrode Mixture 10 Negative Electrode Active Material 14 Negative Electrode Can 16 Flat Non-Aqueous Electrolyte Battery (Conventional) 18 Flat Non-Aqueous Electrolyte Battery (Invention) 20 Ring Body 20a Collar

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohisa Nosue 5-36-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A positive electrode mixture, a separator and a negative electrode active material are laminated in a flat positive electrode can in the presence of a non-aqueous electrolyte,
A flat non-aqueous electrolyte battery in which an opening of the positive electrode can is sealed by a negative electrode can via a gasket, a tubular positive electrode ring provided in the positive electrode can and containing the positive electrode mixture, and the negative electrode. The positive electrode is formed into a tubular shape longer than the vertical expansion length of the positive electrode mixture due to reaction with an active material, and has a flange part that is locked to the top part of the positive electrode mixture at the upper part thereof. A flat type non-aqueous electrolyte battery, comprising: a ring body that is slidably attached to a ring in a vertical direction.