JP3295919B2 - Thin battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to fashion, toys,
The present invention relates to a thin battery used in a field such as an electronic device.

[0002]

2. Description of the Related Art Conventionally, in a thin battery, as shown in FIG. 5, an adhesive 2 as an electric insulator is adhered in a frame shape to an outer peripheral portion of a negative electrode current collector 1 and a negative electrode active material 3 is formed on an inner surface thereof. Of lithium, a lithium alloy, a carbon material, or the like, and a solid polymer electrolyte as a separator 4 is disposed on the upper surface thereof. On the other hand, an adhesive 6 as an electrical insulator (having an inner size slightly smaller than the inner size of the adhesive 2) is adhered in a frame shape to the outer peripheral edge of the positive electrode current collector 5, and the inner surface of the positive electrode active material 7, a metal oxide mixture is disposed. The negative electrode current collector 1 and the positive electrode current collector 5 face each other, and the adhesives 2 and 6 are thermally bonded to each other to produce a thin battery.

In such a conventional battery, after a frame-shaped adhesive 2 is thermally fused to the peripheral region of the negative electrode current collector 1, a negative electrode active material 3 is pressure-bonded to the inner surface thereof, and a separator is further provided on the upper surface thereof. The toner 4 is applied by screen printing and cured to form a mechanically strong film. In the positive electrode current collector 5, after the frame-shaped adhesive 6 is heat-sealed to the peripheral area, the positive electrode active material 7 is printed on the inner surface with a metal mask and cured, and the thickness is substantially the same as the adhesive 6. Alternatively, the printing amount is regulated so as to be small. However, with such a structure, the inner upper surfaces of the adhesives 2 and 6 are contaminated in the above printing, and if the width of the adhesives 2 and 6 is narrow, poor adhesion occurs at the contaminated location, and the sealing performance of the battery is reduced. Bad battery characteristics cannot be obtained.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to regulate the gap and the positional relationship between an electric insulator such as an adhesive and a battery element. Accordingly, an object of the present invention is to prevent a short circuit inside a battery, improve battery characteristics, improve a battery manufacturing process, and obtain a battery structure suitable for mass production.

[0005]

SUMMARY OF THE INVENTION The present invention achieves the above-mentioned object, and comprises a positive electrode active material, a separator and a collector between upper and lower current collectors.
A battery element comprising a battery element, a negative electrode active material, etc., and a peripheral edge of which is sealed with an electrical insulator, wherein a gap between an inner peripheral edge of the electrical insulator and an outer peripheral edge of the battery element is provided. Is 1m
m or less, the thickness of the thin battery is 1 mm or less, the separator covers the entire negative electrode active material surface, and the positions of the outer peripheral edges of the battery elements are shifted and overlapped. That the inner surface of the current collector, in particular, the inner surface near the sealing portion is located inside the sealing surface of the electric insulator, thereby solving the above-described problems. is there.

[0006]

According to the first and second aspects of the present invention, the electrical insulating material can be reduced to one, and after the electrical insulating material is provided on one side of the current collector, it can be bonded to the other side of the current collector. For example, the negative electrode active material is processed into a predetermined shape on the surface of the negative electrode current collector, arranged (for example, pressed and fixed), and a separator is printed thereon and cured.
Further, a positive electrode active material is printed thereon. Such a process can be performed on a series of current collector surfaces where the components of the thin battery are connected in a pattern. After the positive electrode active material is printed, the positive electrode current collector to which the electric insulator is bonded in advance is overlapped and bonded to the outer peripheral surface of the negative electrode current collector, so that the bonding surface of the bonding material is contaminated by the battery element. The airtightness is improved without any problem. Even when the current collectors and battery elements connected in a pattern are integrated with other current collectors, repeated positional accuracy is ensured. That is, when there is a gap of 1 mm or more, when the current collectors are overlapped, an internal minute short circuit occurs between the battery elements and between the current collectors at the outer peripheral portion of the battery elements. For example, the positive electrode active material and the negative electrode active material, the positive electrode active material and the negative electrode current collector, the negative electrode active material and the positive electrode current collector, the positive electrode current collector and the negative electrode current collector are short-circuited. It is particularly effective when the battery is rich in flexibility of 1 mm or less. That is, in the case of 1 mm or more, after the battery element is arranged on the current collector surface on one side in advance, when the electric insulating material is arranged on the peripheral edge, the inner peripheral corner of the electric insulating material contacts the corner of the battery element, In addition, the insulating material is contaminated, causing an internal short circuit and poor adhesion.

According to the third aspect, the entire upper surface of the negative electrode active material is covered with a separator, and even if only one electric insulating material is used, the positive electrode active material and the negative electrode active material, and the negative electrode active material and the positive electrode current collector can be separated. No short circuit. Also, by making the separator larger than the negative electrode active material, the positioning accuracy of the printing plate at the time of printing the separator can be easily controlled, and the management at the time of production becomes easy.

According to the fourth aspect, a short circuit between the battery elements can be prevented. In addition, the arrangement accuracy of each battery element on the current collector surface can be easily controlled, and management during production becomes easy.

According to the present invention, after the battery is completed, the current collector surfaces have internal stresses that face inward with each other. Therefore, after the battery manufacturing procedure as described above, that is, after arranging the battery elements on one current collector surface, Laminate the electrical insulator and the other current collector
Even when the positive electrode active material surface and the positive electrode current collector surface have high electrical contact and mechanical adhesiveness, the internal resistance of the battery is reduced and the discharge or charge characteristics of the battery are improved.

[0010]

Embodiments of the present invention will be described below. FIG. 1 shows a positive electrode current collector 8 (aluminum can also be used) made of stainless steel having a thickness of about 20 .mu., And a negative electrode terminal hole 9 and a slit 10 (a gap between slits is trimmed after the battery is assembled). And a plan view in which the sprocket 11 is provided. Figure 2 shows the same thickness of about 2
A positive electrode terminal hole 13 and a sprocket 14 (having the same pitch as the sprocket 11) are formed in a pattern on the surface of a negative electrode current collector 12 (copper can also be used) made of 0μ stainless steel.
FIG. 3 shows a provided plan view. A negative electrode active material 15 (for example, a lithium foil having a thickness of about 50 μm) is cut into a rectangular shape and pressed in a pattern on the surface of the negative electrode current collector 12. FIG. 3 is a cross-sectional view of a main part when another battery element is further arranged on the surface of the negative electrode current collector 12. FIG. 4 shows a structure in which an adhesive 18 is adhered to each pattern portion of the positive electrode current collector 8, and the negative electrode current collector 1 as shown in FIG.
FIG. 2 shows an enlarged cross-sectional view of the case where 2 ′, the bonding adhesive 18 and the negative electrode current collector 12 ′ are bonded. The polymer solid electrolyte 1
The shape of the separator 6 (separator) differs between FIG. 3 and FIG. 4 due to the difference in the protrusion width when the polymer solid electrolyte is printed on the surface of the negative electrode active material 15, and when it is about 0.5 mm larger. Does not hang. However, the solid polymer electrolyte 1 at the time of printing
6 and the like.

In FIG. 4, the portion A of the positive electrode current collector 8 'is inside the bonding surface of the adhesive 18 when the adhesive 18 is bonded, and when the adhesive 18 is bonded to the negative electrode current collector 12'. As shown, the current collector surface corresponding to the battery element is thicker than the peripheral edge. Although the shapes of the current collectors of the positive electrode and the negative electrode are different in the drawing, they may be the same. Further, since the thickness of the battery itself is thin, it is difficult to understand the appearance, but it becomes clear when the cross section is observed and when an electric insulator (adhesive 18) is attached to one current collector surface in advance. This inward deformation stress increases the degree of contact between battery elements when the battery is used. On the other hand, the adhesive at the inner peripheral edge of the adhesive 18 protrudes slightly inside, that is, toward the battery element side.

With respect to the gap between each battery element of such a thin battery having a thickness of about 0.3 mm and the electrical insulating material, the gap between the negative electrode active material 15 and the adhesive 18 is about 0.4 mm on one side and about 0.4 mm on the opposite side. About 0.6 mm, and the separator 16 and the adhesive 18
Is about 0.2 mm on one side and about 0.4 mm on the other side, and the gap between the positive electrode active material 17 and the adhesive 18 is about 0.5 mm on one side and about 0.5 mm on the other side.

A card-sized thin battery of the present invention, in which a total of 16 thin batteries of the present invention are connected from a series of batteries, four in the width direction and four in the length direction, and a conventional configuration. As a result of conducting a bending test, a discharge test, a storage test, and the like on a battery having the same card size, in the bending test, an internal short circuit occurred at about 600 to 700 times at a conventional deflection of 2 cm. Of 1000
Satisfied enough times. On the other hand, in the discharge test, when the battery was stopped in the middle of the conventional discharge, about 15% of the batteries showed an abnormal decrease in the open circuit voltage, whereas the battery of the present invention showed no abnormality. Further, when a storage test was performed at about 60 ° C. and a humidity of 90%, even after elapse of 20 days, almost no decrease in the open circuit voltage due to an internal short circuit or the like was observed. Conventionally, a voltage drop of several tens mV to several hundred mV has been observed.

The gap between the electric insulator and the battery element is 1 m
m or less, but preferably 0.5 mm or less. That is, when the gap between the outer periphery of one member of the battery element and the inner periphery of the electric insulating material is 1 mm or less, when one gap is 0 mm, the other is about 2 m.
m gaps. Therefore, when the gap between one battery element is increased, the effect of the present invention is further enhanced by reducing the gap between the other battery elements and shifting the center positions of the battery elements.

[0015]

The present invention has the following effects. (1) It is suitable for multi-product small-quantity production, such as obtaining a thin battery of a predetermined shape and capacity by separating an arbitrary number from a series of thin batteries. (2) When arranging battery elements by means such as printing,
This is effective in preventing a short circuit between each battery element. (3) After arranging the battery element on the current collector, positioning becomes easy when the electric insulator is arranged and bonded, and the quality is stabilized without damaging the battery element or contaminating itself. . (4) In a flexible thin battery, an internal short circuit due to deformation of a battery element at the time of bending is prevented. In the present invention, there are no particular limitations on the materials and sizes of the current collector and the electrical insulator, the shift width of each of the battery elements, and various cases can be considered. The material and thickness of the battery element are not particularly limited. Means for improving the adhesion between the positive electrode active material surface and the positive electrode current collector surface and lowering the electric resistance (for example, undercoating) is not specifically described. However, one method for embodying the constitution of the present invention is described below. It is a necessary measure when thinking.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a series of connected positive electrode current collectors according to the present invention, in which one section forms one thin battery.

FIG. 2 is a plan view showing an example of a series of connected negative electrode current collectors according to the present invention, in which one section forms one thin battery.

FIG. 3 is a cross-sectional view illustrating a case where another battery element is disposed on the negative electrode active material of FIG. 2;

FIG. 4 is a sectional view of one of the thin batteries of the present invention.

FIG. 5 is a sectional view of a main part of a conventional battery.

[Explanation of symbols]

 1, 12, 12 'Negative electrode current collector 2, 6, 18 Electrical insulator (adhesive) 3, 15 Negative electrode active material 4, 16 Separator 5, 8, 8' Positive electrode current collector 6, 7, 17 Positive electrode Active material

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-108278 (JP, A) JP-A-5-198289 (JP, A) Japanese Utility Model SHO 59-99355 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) H01M 2/02-2/08 H01M ^6/ 00-6/22 H01M 10/36-10/40

Claims (4)

(57) [Claims] 1. A thin battery in which a battery element comprising a positive electrode active material, a separator, and a negative electrode active material is disposed between current collectors on upper and lower surfaces, and the periphery of which is sealed with an electrical insulator, Said thin
The thickness of the battery is 1 mm or less, and the distance between the inner peripheral end of the electrical insulator and the outer peripheral end of the battery element is 1 mm or less .
A thin battery having a thickness of 2 mm or more . 2. The thin battery according to claim 1 , wherein the separator covers the entire surface of the negative electrode active material. 3. The thin battery according to claim 1, wherein the outer peripheral ends of the battery elements are shifted from each other and are superposed. Wherein said collector body surface, according to claim 1 to 3 thin batteries wherein that from the sealing surface of the electrical insulator to the inside.