JPH11345604A - Lithium secondary battery and battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of current collecting of a lithium secondary battery and make the lithium secondary battery maltiply functional. SOLUTION: This battery is structured comprising a conductive layer 1 of lithium ion, a negative electrode, a positive electrode and a battery casing 6. The negative electrode comprises a negative electrode active material layer 4, which can store and eject lithium placed contacting with the conductive layer 1, and a negative electrode collector substrate 5 holding the negative electrode active material layer 4. The positive electrode comprises a positive electrode active material layer 2, which can store and eject lithium placed contacting with a side of the conductive layer 1 opposite to a side contacting the negative electrode active material layer 4, and a positive electrode collector substrate 3 holding the positive electrode active material layer 2. The battery casing 6 accommodates the conductive layer 1 of lithium ion, the positive electrode and the negative electrode. A positive terminal 7 and a negative terminal 8 having a plurality of points are provided on an outer surface of the battery casing 6. The positive terminal 7 and the negative terminal 8 are connected to the positive electrode collector substrate 3 and the negative electrode collector substrate 5, respectively, via a conductor filled in via holes formed in the battery casing 6. An electric circuit connected to the positive terminal 7 or the negative terminal 8 is provided on the outer surface of the battery casing 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery and a battery module, and more particularly to an improvement in battery load characteristics and a multifunctional lithium secondary battery.

[0002]

2. Description of the Related Art A lithium secondary battery has a high voltage and a high energy density, and has excellent storage performance and repetitive charge / discharge characteristics, and is widely used in portable consumer electric products.
Also, research and development for increasing the size of this battery and using it as a nighttime power storage device for electric vehicles and homes for leveling power demand have been actively conducted.

Hitherto, the structure of these batteries has been housed in a container such as a metal or plastic can or a bag-like container, and only a pair of terminals of a positive electrode and a negative electrode is provided in one of these containers. there were.

[0004]

However, in such a structure, if the size of the electrode is increased in order to increase the battery capacity, the current collector becomes large, and if current is taken out from one battery terminal, the electric resistance increases. As a result, there is a problem that the load characteristics of the battery deteriorate. In addition, lithium secondary batteries have better storage stability and cycle life after repeated charge / discharge than conventional nickel-metal hydride batteries, nickel-cadmium batteries, and lead batteries, eliminating the need for frequent battery replacement. That is,
Since this battery has the durability as an electronic component, if the battery and the electronic component are integrated, it is possible to further reduce the weight and thickness of the total system.

[0005] It is an object of the present invention to provide a lithium secondary battery capable of integrating a battery and electronic components without deteriorating load characteristics even when a large current is taken out.

[0006]

Means for Solving the Problems These problems can be realized by devising a method of extracting the electrode terminals, and the present invention has been accomplished. That is, in order to extract as much current as possible from the electrode current collector, a plurality of electrode terminals are dispersedly arranged on the outer surface of the battery housing, and the inner and outer surfaces of the battery housing are connected to the battery housing at the electrode terminal position. A conductor that electrically connects a surface of the current collector that is not in contact with the electrode active material layer and the electrode terminal disposed on the outer surface side of the battery case is opened in the battery case. This can be achieved by arranging through the via holes provided. In this case, the positive and negative electrode current collectors are:
It is desirable that the electrode active material layer is disposed so as to be in contact with the electrode active material layer over the entire planar spread.

Further, if a via hole connecting the front and back of the battery housing is formed in a portion not in contact with the battery structure of the battery housing, both the positive and negative terminals can be formed on one or both surfaces of the housing surface. The electrical circuit can be formed in any manner by the technique. In this way, a product with a new concept in which the lithium secondary battery and the circuit board are integrated can be created.

[0008]

Embodiments of the present invention will be described below. FIG. 1 is a sectional view of a lithium secondary battery according to an embodiment of the present invention. The illustrated battery includes a flat lithium ion conductive layer 1, a flat positive electrode active material layer 2 disposed in contact with one surface (the upper surface in FIG. 1) of the lithium ion conductive layer 1, and a positive electrode. A plate-like positive electrode current collector substrate 3 arranged in contact with the upper surface of the active material layer 2 and a plate-like negative electrode arranged in contact with the other surface (the lower surface in FIG. 1) of the lithium ion conductive layer 1 The active material layer 4, a flat negative electrode current collector substrate 5 disposed in contact with the lower surface of the negative electrode active material layer 4, and a box-shaped exterior body (hereinafter, referred to as a battery housing) 6 that accommodates these.
A plurality of via holes (through holes) formed in a wall body 6A of the battery housing 6 facing the positive electrode current collector substrate 3, and one end of an intermediate portion filled in the via hole of the wall body 6A. A plurality of positive terminals having a land portion 7A disposed on the outer surface of the wall body 6A in contact with the positive electrode current collector substrate 3 and connected to the other end of the intermediate portion, facing the negative electrode current collector substrate 5; Via holes (through holes) formed in the wall 6B
And a land portion 8A disposed on the outer surface of the wall 6B by connecting one end of an intermediate portion filled in the via hole of the wall 6B to the negative electrode current collector substrate 5 and connecting to the other end of the intermediate portion. And a plurality of negative electrode terminals.

First, an increase in the number of electrode terminals can be realized by using a battery having the shape shown in FIG. Here, for the conductive layer 1 of lithium ions, a liquid electrolyte, a gel, or a solid electrolyte can be used. However, in the case of a liquid electrolyte, the lithium ion conductive layer 1 is composed of the electrolyte and the separator.
At this time, the material of the housing is not limited as long as it is an insulating material. For example, a material used for a flexible substrate such as a polyimide resin or PET can be used while imparting a sealing property to a battery.

Hereinafter, a first embodiment of the present invention will be described. In Example 1, graphite carbon was used as the negative electrode active material, and polyvinylidene fluoride (hereinafter abbreviated as PVDF) was used as the binder.
And applying a paste obtained by dissolving graphite carbon and PVDF in N-methylpyrrolidone (hereinafter abbreviated as NMP) to the copper foil surface of a 20 μm-thick single-sided PET film substrate.
Heat and pressure molding was performed to obtain a negative electrode. The copper foil forms the negative electrode current collector substrate 5. The thickness of the negative electrode active material layer after the pressure molding was about 50 μm. Lithium cobaltate was used as the positive electrode active material, PVDF was used as the binder, amorphous carbon was used as the conductive additive, and lithium cobaltate, PVD
A paste in which F and amorphous carbon were dissolved in NMP was applied to the aluminum foil surface of a single-sided PET film having a thickness of 20 μm, and was heated and pressed to obtain a positive electrode. The aluminum foil forms the positive electrode current collector substrate 3. The thickness of the positive electrode active material layer after pressure molding was about 100 μm. Also, 30% by volume of ethylene carbonate and 70% of dimethyl carbonate
Lithium hexafluorophosphate was added to the solution containing 1 vol.
The electrolytic solution obtained by dissolving the liter was sufficiently impregnated into a separator (Tonen Tapyrus) having a thickness of 40 microns. This constitutes the lithium ion conductive layer 1. The size of these electrodes (collector substrate) was 5 cm in width and 10 cm in length, and the separator was 6 cm in width and 12 cm in length.

In the single-sided PET film to be the battery case 6, via holes having a diameter of 0.5 mm are formed in advance at equal intervals of 2 cm by laser processing, and uniform vias are formed by electroless copper plating. After forming the copper conductor filled in the hole, a uniform land having a diameter of 0.7 mm (electrode portions 7A and 8A formed on the outer surface of the battery housing 6 in FIG. 1) by electroless copper plating. ) And a plurality of positive terminals 7 and negative terminals 8
Is formed. Thereafter, the above-mentioned copper foil or aluminum foil serving as a current collector was bonded to form a single-sided PET film substrate for a negative electrode or a positive electrode, and was subjected to the application of the paste.

Next, the positive and negative electrodes prepared above were sandwiched by the separator with the PET film side on which the multipoint connection portion was formed facing outward, and the periphery was hot-melt-compressed to produce the battery of Example 1. The initial discharge capacity of this battery was 150 mAh at a current of 0.5 mA, and the average discharge voltage was 3.6 V. Further, the load characteristics are 150 mA at 1.5 mA or 3 mA.
It showed a discharge capacity of mAh, confirming that the load characteristics were good. This means that the size of the current collector is
Alternatively, the effect is obtained by reducing the internal resistance of the battery by providing a plurality of electrode terminals with the same size as the negative electrode active material layer.

In the above embodiment, a paste containing a negative electrode active material or a positive electrode active material was applied to a copper foil surface or an aluminum foil surface of a single-sided PET film having a copper foil or an aluminum foil adhered to one side. PET film, and a negative electrode active material layer or a positive electrode active material layer holding a copper foil or an aluminum foil as a current collector separately, containing the negative electrode active material or the positive electrode active material in a copper foil or an aluminum foil The negative electrode and the positive electrode may be formed by applying a paste, heating and press molding. The PET film is processed in the same manner as in the above embodiment, and
A multipoint connection is formed. In this case, the positive and negative electrodes are sandwiched by the separator with the copper foil or the aluminum foil on the outside, and the outside of the separator is formed with a multipoint connection portion.
After being sandwiched between ET films, the periphery is heat-melted and pressed to produce the battery of Example 1.

In the battery shown in FIG. 1, the positive terminal is disposed separately from the upper surface of the battery, and the negative terminal is disposed separately from the lower surface of the battery. However, as in the second embodiment shown in FIG. If both positive and negative poles are formed on one surface, a circuit can be formed on this surface. In FIG. 2, a plurality of negative land portions 8A are formed on the outer surface of the upper wall 6A of the battery housing 6, and the negative electrode 8 pulled out to the lower wall 6B of the battery housing 6 and the upper wall are formed. A wiring 9 is provided as an electric circuit for connecting the land 8A of the negative electrode formed on the body 6A. Conversely, a plurality of positive electrode lands 7A are formed on the outer surface of the lower wall 6B of the battery housing 6, and the positive electrode terminals 7 drawn out to the upper wall 6A of the battery housing 6 are connected to the battery housing 6. The wiring 10 may be provided as an electric circuit connected to the plurality of positive land portions 7A formed on the lower wall 6B of the body 6. The wirings 9 and 10 include via holes for routing the positive electrode from the upper end to the lower end of the battery housing 6 and the negative electrode from the lower end to the upper end of the battery housing 6, respectively. Further, the battery housing 6
A negative land 8A is formed on the outer surface of the upper wall body 6A, and a plurality of positive land parts 7A are formed on the outer surface of the lower wall 6B of the battery housing 6, respectively. By providing them, both terminals of a positive electrode and a negative electrode can be provided on both outer surfaces of the wall bodies 6A and 6B.

In order to further increase the mounting density and improve the functions, the circuit boards 6C and 6D are formed on the outer surface of the battery housing 6 provided with the electric circuit in the shape as in the third embodiment shown in FIG.
It is also possible to form a laminate through the adhesive layer 11. With this configuration, an electric circuit can be easily formed on both the upper and lower surfaces of the battery. For the circuit boards 6C and 6D, materials conventionally used for thin-film multilayer wiring boards can be used as they are.

Further, the battery having the shape shown in FIG.
The battery can be easily connected in series by stacking it in the shape of the embodiment.

When a battery having the shape shown in FIG. 3 having positive and negative electrodes in one plane is laminated on the shape of the fifth embodiment shown in FIG. 5, a battery of a parallel connection type can be easily formed.

Further, electronic parts can be easily mounted on the battery having the shape shown in FIG. 2, and as in the sixth embodiment shown in FIG. 6, lithium having electronic parts 12, 13 such as integrated circuits is mounted. A secondary battery can be formed. If this electronic circuit is used, it is possible to directly mount a safety protection circuit such as to avoid overcharging, overvoltage and overcurrent on the battery itself. In FIG. 6, a signal line 1 for transmitting outputs from the electronic components 12 and 13 is shown.
4 are provided.

Further, a battery module can be easily formed by arranging and storing the batteries of FIG. 1 in a cassette having a matching shape as in the seventh embodiment shown in FIG. A positive electrode terminal 15 and a negative electrode terminal 16 are formed in the module case 17, and a battery module connected in parallel can be formed only by inserting a battery into the cassette case 17. Although this example shows a parallel connection, the connection can be easily changed by changing the wiring of the cassette case 17 in order to make the connection in series. Further, in order to ensure the safety of the battery, the inside of the module kale 17 is filled with an inert gas or a nonflammable liquid or
It can be filled with non-combustible inorganics or fire extinguisher or flame retardant.

[0020]

As described above, if the multipoint connection portion is formed on the outer surface of the battery case, the load characteristics can be improved. In addition, if this battery structure is used, a circuit can be formed in a lithium secondary battery, and it becomes possible to create a product with a new concept that combines a battery and a circuit board.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing a fifth embodiment of the present invention.

FIG. 6 is a perspective view showing a sixth embodiment of the present invention.

FIG. 6 is a sectional view showing a seventh embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 lithium ion conductive layer (electrolyte and separator, or gel electrolyte, or solid polymer electrolyte) 2 positive electrode active material layer 3 positive electrode current collector substrate 4 negative electrode active material layer 5 negative electrode current collector substrate 6 battery housing 6A , 6B wall 7 connecting via hole and positive electrode terminal 7A land portion of positive electrode terminal 8 connecting via hole and negative electrode terminal 8A land portion of negative electrode terminal 9 through via hole negative electrode wiring 10 through through hole positive electrode wiring 11 adhesive layer 12, 13 electronic component 14 Signal wiring 15 Module positive terminal 16 Module negative terminal 17 Module case

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[Procedure amendment]

[Submission date] September 7, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a sectional view showing a fifth embodiment of the present invention.

FIG. 6 is a perspective view showing a sixth embodiment of the present invention.

FIG. 7 is a sectional view showing a seventh embodiment of the present invention.

[Description of Signs] 1 Lithium ion conductive layer (electrolyte and separator, or gel electrolyte, or solid polymer electrolyte) 2 Positive electrode active material layer 3 Positive electrode current collector substrate 4 Negative electrode active material layer 5 Negative electrode current collector substrate Reference Signs List 6 Battery case 6A, 6B Wall 7 Connection via hole and positive electrode terminal 7A Land portion of positive electrode terminal 8 Connection via hole and negative electrode terminal 8A Land portion of negative electrode terminal 9 Through via hole negative electrode wiring line 10 Through via hole positive electrode wiring line 11 Adhesive layer 12 , 13 Electronic components 14 Signal wiring 15 Module positive terminal 16 Module negative terminal 17 Module case

Claims (10)

[Claims] 1. A negative electrode comprising an electrolyte, a negative electrode active material layer disposed in contact with the electrolyte and capable of inserting and extracting lithium, and a negative electrode comprising a current collector holding the negative electrode active material layer; A positive electrode comprising a positive electrode active material layer capable of inserting and extracting lithium and a current collector holding the positive electrode active material layer,
In a lithium secondary battery comprising the electrolytic solution and a package housing a positive electrode and a negative electrode, a multipoint positive electrode and a negative electrode connected to the positive or negative current collector on the surface of the package are provided. A lithium secondary battery having an electrode terminal. 2. The lithium battery according to claim 1, wherein the exterior body has an electric circuit connected to or connectable to a multipoint electrode terminal provided on a surface of the exterior body. Next battery. 3. The lithium secondary battery according to claim 1, wherein the outer body has a function as a laminated substrate having an electric circuit therein. 4. A flat lithium ion conductive layer serving as an electrolytic solution, a flat positive electrode active material layer disposed in contact with one surface of the conductive layer, and the conductive layer of the positive electrode active material layer. A plate-shaped positive electrode current collector disposed in contact with a surface opposite to the surface in contact with the layer; a plate-shaped negative electrode active material layer disposed in contact with the other surface of the conductive layer; A flat plate-shaped negative electrode current collector arranged in contact with the surface of the layer opposite to the surface in contact with the conductive layer, and an exterior body forming a container for accommodating these, and the exterior body is A via hole formed in a wall facing the positive electrode current collector, a conductor filled in the via hole, and a land connected to the conductor and located on an outer surface of the wall and serving as an electric circuit connection point And a terminal of a positive electrode comprising: and a via formed in a wall facing the negative electrode current collector A negative electrode terminal comprising: a hole; a conductor filled in the via hole; and a land connected to the conductor and located on an outer surface of the wall and serving as an electric circuit connection point. The inner end of the terminal of the electrode is in contact with the positive electrode current collector facing the wall, and the inner end of the terminal of the negative electrode is in contact with the negative electrode current collector facing the wall. Item 7. A lithium secondary battery according to Item 1. 5. A plurality of negative electrode lands are formed on an outer surface of a wall of an exterior body on which a positive electrode terminal is provided, and a plurality of the negative electrode lands and a negative electrode terminal are provided. 5. The lithium secondary battery according to claim 4, wherein a circuit for connecting a land portion of the negative electrode or a negative electrode current collector on an outer surface of a wall of the exterior body is formed. 6. A plurality of lands of a positive electrode are formed on an outer surface of a wall of an exterior body provided with terminals of a negative electrode, and a plurality of lands of the positive electrode and a terminal of a positive electrode are provided. 5. The lithium secondary battery according to claim 4, wherein a circuit for connecting the land portion of the positive electrode or the positive electrode current collector on the outer surface of the wall of the exterior body is formed. 7. The rechargeable lithium battery according to claim 2, wherein at least one of an integrated circuit, a semiconductor, a capacitor, and a resistor is mounted on an electric circuit portion of the exterior body. 8. The overcharge, overvoltage,
8. A safety protection circuit capable of controlling at least one abnormality among overcurrents.
The lithium secondary battery according to any one of the above. 9. A battery module comprising a combination of a plurality of lithium secondary batteries, wherein the lithium secondary battery is the lithium secondary battery according to any one of claims 1 to 8, wherein the lithium secondary batteries are A battery module characterized by being housed in a cassette case in a module case. 10. The space inside the module case is formed of an inert gas, a non-flammable liquid, or a non-flammable inorganic substance.
The battery module according to claim 9, wherein the battery module is filled with a fire extinguishing agent or a flame retardant.