JPH07130351A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PURPOSE:To suppress excessive heat generation in the battery inside, increase the output density per unit weight and unit volume, remarkably lower the manufacturing cost, and improve the production yield. CONSTITUTION:An electrode part 1 is composed by arranging a plurality of coiled electrode elements 11 in parallel and symmetric positions and bundling them by a belt or a thermally shrinkable tube 32. A negative electrode lead 12 made of Ni and a positive electrode lead 12 made of pure aluminum are connected with each coiled electrode element 11 and the divided negative electrode leads 12 are converged into one negative electrode lead 12. A heat sensitive battery shutting element 16, which is a protective element, is connected with each positive electrode lead 13 in series and at the tips, the divided positive electrode leads 13 are converged into one positive electrode lead 13 in the same way as the negative electrode leads 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to the structure of its electrode portion.

[0002]

2. Description of the Related Art Recent remarkable advances in electronic technology have made electronic devices smaller and lighter one after another. Along with this, batteries, which are used as mobile power sources, are required to be smaller and lighter and have high energy density.

Conventionally, an aqueous solution type secondary battery such as a lead battery or a nickel-cadmium battery has been mainly used as a secondary battery for general use. However, although these aqueous secondary batteries have excellent cycle characteristics, they cannot be said to be sufficiently satisfactory in terms of battery weight and energy density.

Therefore, recently, a material capable of doping and dedoping lithium ions such as lithium, a lithium alloy and a carbon material is used as a negative electrode, and a lithium composite oxide such as a lithium cobalt composite oxide is used as a positive electrode. Research and development of a non-aqueous electrolyte secondary battery using a battery have been actively conducted. This battery has a high battery voltage, a high energy density, and excellent cycle characteristics.

Taking a cylindrical non-aqueous electrolyte secondary battery as an example, as shown in FIG. 8, a negative electrode current collector 10 is used.
6, a negative electrode 101 formed by applying a negative electrode active substance and a positive electrode 102 formed by applying a positive electrode active substance on a positive electrode current collector 107 are wound around a separator 103, and an insulator is provided above and below the wound body. The battery pack 105 is housed in a battery container 105 with 104 mounted thereon.

A battery lid 108 is attached to the battery container 105 by caulking via a sealing gasket 109, and the negative electrode lead 110 and the positive electrode lead 1 are respectively attached.
It is electrically connected to the negative electrode 101 or the positive electrode 102 via 11 and is configured to function as the negative electrode or the positive electrode of the battery.

[0007]

However, in the conventional non-aqueous electrolyte secondary battery, when the capacity is increased, heat generation inside the battery container increases at the end of discharge as it is used, and Even if a heavy load such as an electronic load is applied to the battery, the heat generated inside the battery container is large and the battery performance (energy density, power density, cycle characteristics, etc.) is significantly deteriorated, resulting in a high-performance battery. Things are very difficult.

Further, as the capacity of the non-aqueous electrolyte secondary battery is increased, the surface area of the electrodes (the positive electrode 101 and the negative electrode 102) and the like which are the constituent elements also becomes large. When used, the rate of occurrence of short circuits inside the battery significantly increases. Moreover, since the electrodes and the like have a large surface area, the manufacturing cost is naturally high, and the yield is reduced.

In addition to the above, it is technically possible to maintain the high output density of the electrode having a large surface area while maintaining the adhesion between the positive electrode 101 and the negative electrode 102 and densifying the electrode while not deteriorating the battery performance. Have difficulty. At present, such various problems are major obstacles to the realization of the large capacity of the non-aqueous electrolyte secondary battery.

The present invention has been made in view of the above-mentioned various problems, and it is an object of the present invention to easily and inexpensively realize a large capacity and to prevent excessive heat generation inside the battery. To provide a non-aqueous electrolyte secondary battery which can suppress and increase the output density per unit weight and unit volume and further can significantly reduce the manufacturing cost to improve the yield. It is in.

[0011]

According to the present invention, a plurality of spirally wound electrode elements in which a positive electrode and a negative electrode are wound with a separator interposed therebetween are housed in the same battery container and connected in parallel, and a nonaqueous solvent is used. Inject a non-aqueous electrolyte solution in which the electrolyte is dissolved,
Moreover, a protective element is coupled to the lead of each wound electrode element,
The battery container is provided with a safety valve that opens when the internal pressure of the battery container rises abnormally.

In this case, the protective element is constituted by using a thermal battery cutoff element and / or a fuse.

Further, in this case, the protection element may be constituted by connecting the thermal battery cutoff element and the fuse in series.

[0014]

In the non-aqueous electrolyte secondary battery according to the present invention,
Since a large number of wound electrode elements are coupled in parallel and efficiently housed in the battery container, the surface area of the electrodes (positive electrode and negative electrode) of the battery as a whole becomes very large. Therefore,
Since the entire battery has a large energy density, it is possible to efficiently output.

Furthermore, since a protective element (heat-sensitive battery blocking element or fuse) is coupled to the output lead of each of the wound electrode elements, high temperature suppression is performed for each of the wound electrode elements, resulting in a battery. The overall temperature will be suppressed within the allowable range.

[0016]

EXAMPLES Examples of the non-aqueous electrolyte secondary battery according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the non-aqueous electrolyte secondary battery according to this embodiment comprises an electrode portion 1, an upper lid portion 2 and a battery container portion 3.

A plurality of electrode parts 1 (7 in the illustrated example)
Of the spirally wound electrode elements 11 are arranged in parallel and have a symmetrical shape (6 in the illustrated example).
It is arranged in a rectangular shape, and as shown in FIG. 2, a belt or a tube 32 having heat-shrinkability is used for binding. Each wound electrode element 11 has a negative electrode lead 12 made of Ni and a positive electrode lead 1 made of pure Al.
3 are connected, and the branches of each negative electrode lead 12 are integrated into one negative electrode lead 12. Further, a thermal battery cutoff element 16 which is a protection element is connected in series to each positive electrode lead 13, and the branches of each positive electrode lead 13 are integrated into one positive electrode lead 13 in the same manner as the negative electrode lead 12 after that. There is.

Each wound electrode element 11 has a negative electrode made of a negative electrode current collector made of copper coated with a carbon material (for example, KH carbon) capable of doping or dedoping lithium or bonded with metallic lithium, and Al. And a positive electrode obtained by applying LiCoO ₂ , which is a composite oxide of lithium and a transition metal, to a positive electrode current collector made of a material such that a plurality of sets are wound and arranged via a separator made of polyethylene or polypropylene. Has been done.

A polyswitch PTC (Positive Temperer Coefficient) element manufactured by Raychem Co., Ltd. is used as the thermal battery cutoff element 16 which is a protective element. As shown in FIG. 3, the thermal battery cutoff element 16 has a torus shape and has a structure in which a PTC element 22 is sandwiched between an upper plate 21 and a lower plate 23 made of Ni.

The thermal battery cutoff element 16 is an element having a function of delicately limiting the electric current by being heated by an increase in the ambient temperature and rapidly increasing the electric resistance when the temperature rises. The PTC element 22 which is a component of the thermal battery cutoff element 16 is made of carbon which is a conductor and polymer which is an insulator. The nature of the PTC element 22 is that carbon, which is a conductor in normal times, is connected (metaphorically, a polymer island is suspended in a sea of carbon), and a path through which electrons pass (conduction) However, when the temperature exceeds a certain critical temperature by heating, each polymer is connected and the carbon connection is cut off, and electrons cannot conduct. That is, as shown in FIG. 4, when a certain critical temperature (120 ° C. in the illustrated example) is reached, the resistance value rapidly increases (100,000 times or more) and the current value is suppressed.

The upper lid portion 2 is formed on a circular substrate 20.
The negative electrode terminal 14 and the positive electrode terminal 15 are installed via the insulating materials 18 and 19, and the negative electrode terminal 14 and the positive electrode terminal 15 are provided.
A negative electrode lead wire 12 and a positive electrode lead 13 are electrically connected to and electrically connected to each other. Further, the upper lid portion 2 is configured to have a safety valve 17 that is opened according to an abnormal increase in the battery internal pressure during use of the battery to reduce the internal pressure.

The battery container 3 is made of a synthetic resin plate or iron plate of polyethylene or polypropylene having a high specific strength and plated with Ni having a high thermal conductivity, has a cylindrical shape, and has an opening 3a at its upper part. Have. This opening 3a
In the battery container part 3, the electrode part 1 in which each wound electrode element 11 is bound by a belt or a heat-shrinkable tube 32 is arranged via a polyethylene sheet, and the electrolyte is dissolved in a non-aqueous solvent. By injecting the water electrolytic solution through the opening 3a to immerse the electrode portion 1 and joining and fixing the upper lid portion 2 to the opening 3a by using ultrasonic waves or thermocompression, the non-contact according to the present embodiment A water electrolyte secondary battery is configured.

Here, when Ni plating is applied to the inner surface or the outer surface of the battery container portion 3 in consideration of the improvement of heat dissipation and a Ni plating layer is formed, the joint portion of the battery container portion 3 is plated with Ni. In that case, there is a disadvantage that it is difficult to cause welding at the time of joining. Therefore, it is preferable to mask this joining portion and apply Ni plating to the battery container portion 3.

In the above embodiment, the thermal battery cutoff element 16 is used as the protection element, but a fuse having a current cutoff effect at a certain critical temperature or higher may be used as the protection element.

In the non-aqueous electrolyte secondary battery according to the above embodiment, a large number of spirally wound electrode elements 11 are connected in parallel and efficiently housed in the battery container 3, so that the electrode () The surface area of the positive and negative electrodes is very large. Therefore, since the battery as a whole has a large energy density, it is possible to efficiently output.

As a result, the power density per unit weight and unit volume of the battery is significantly increased, and the battery performance can be improved.

Further, since the protective element (the thermal battery breaking element 16 or the fuse) is coupled to the output lead of each wound electrode element 11, the high temperature is suppressed for each wound electrode element 11 and, as a result, The temperature of the entire battery is suppressed within the allowable range.

Therefore, it is possible to surely suppress the heat generation inside the battery during use, which is a big problem of the conventional non-aqueous electrolyte secondary battery, and deteriorate the battery performance (energy density, power density, cycle characteristics, etc.). Can be prevented.

Next, some modifications of the above embodiment will be described with reference to the drawings. The same reference numerals are given to those corresponding to FIG.

First, a first modification is shown in FIG. This first modified example has almost the same configuration and function as the above-mentioned embodiment, but mainly the battery container portion 3 which is a constituent element of the non-aqueous electrolyte secondary battery according to the above-mentioned embodiment is The difference is that the battery container portion 31 has a rectangular shape.

That is, in the first modification,
A plurality of (seven in the illustrated example) spirally wound electrode elements 11 are installed in a line in a rectangular battery container portion 31, and the negative electrode lead 12 and the positive electrode lead 13 are connected in the same manner as in the above embodiment. , The branch of each negative electrode lead 12 is one negative electrode lead 1
2 and are connected to the negative electrode terminal 14 provided in the lower portion of the battery container portion 31 to conduct electricity. Further, a thermal battery cutoff element 16 which is a protection element is connected in series to each positive electrode lead 13, and the branches of each positive electrode lead 13 are integrated into one positive electrode lead 13 in the same manner as the negative electrode lead 12 after that. It is connected to the positive electrode terminal 15 provided on the upper lid 2 to conduct electricity.

In the first modification, a plurality of spirally wound electrode elements 11 are connected in parallel to form an electrode portion 1 as in the above embodiment, and the electrode portion 1 is not placed inside the battery container portion 31. It is soaked in a water electrolytic solution, housed therein, and closed by the upper lid portion 2.

Also in the first modification, as in the above-described embodiment, a large number of spirally wound electrode elements 11 are coupled in parallel and efficiently housed in the battery container 31, so that the electrodes of the entire battery are The surface area of (positive electrode and negative electrode) becomes very large. Therefore, since the battery as a whole has a large energy density, it is possible to efficiently output.

As a result, the power density per unit weight and unit volume of the battery is significantly increased, and the battery performance can be improved.

Further, as in the above-described embodiment, since the output lead of each wound electrode element 11 is connected to the protection element (the heat-sensitive battery cutoff element 16 or the fuse), the high temperature of each wound electrode element 11 is suppressed. As a result, the temperature of the entire battery is suppressed within the allowable range.

Therefore, heat generation inside the battery during use, which is a major problem of the conventional non-aqueous electrolyte secondary battery, can be reliably suppressed, and the battery performance (energy density, power density, cycle characteristics, etc.) is deteriorated. Can be prevented.

Next, a second modification is shown in FIG. The second modified example has substantially the same configuration and function as the above-described embodiment, but is mainly provided with a plurality of electrode parts 1 to form an electrode part 4.
The difference is that it is 1.

That is, in the second modification, a plurality of electrode parts 1 (three in the illustrated example) are connected in parallel, and a plurality of electrode parts 1 (three in the illustrated example) are formed. Individual pieces) are installed in the battery container portion 3 to form the electrode portion 41.

Here, each wound electrode element 11 of each electrode portion 1
The negative electrode lead 12 and the positive electrode lead 13 are connected to each other, the branches of each negative electrode lead 12 are integrated into one negative electrode lead 12, and the combined negative electrode lead 12 of each electrode unit 1 is further connected to form one negative electrode lead 12. It becomes the negative electrode lead 12 and is connected to the negative electrode terminal 14 provided on the lower portion of the cylindrical shape of the battery container part 3 to conduct electricity. In addition, the branches of the positive electrode leads 14 to which the thermosensitive battery cutoff elements 16 that are protection elements are connected in series are aggregated into one positive electrode lead 14, and the aggregated positive electrode leads 14 of each electrode unit 1 are further connected. As a result, a single negative electrode lead 12 is formed, which is connected to the negative electrode terminal 15 provided on the upper lid portion 2 to conduct electricity.

In the second modification, a plurality of electrode parts 1 in which a large number of wound electrode elements 11 are connected in parallel are provided and efficiently housed in the battery container part 3 as the electrode parts 41. The surface area of the electrodes (positive electrode and negative electrode) as a whole becomes very large. Therefore, since the battery as a whole has a large energy density, it is possible to output more efficiently.

As a result, the power density per unit weight and unit volume of the battery is significantly increased, and the battery performance can be further improved.

Further, as in the above-mentioned embodiment, since the protective element (the heat-sensitive battery cutoff element 16 or the fuse) is coupled to the output lead of each wound electrode element 11, the high temperature of each wound electrode element 11 is suppressed. As a result, the temperature of the entire battery is suppressed within the allowable range.

Therefore, heat generation inside the battery during use, which was a major problem of the conventional non-aqueous electrolyte secondary battery, can be surely suppressed, and the battery performance (energy density, power density, cycle characteristics, etc.) is deteriorated. Can be prevented.

Next, FIG. 7 shows a third modification. The third modification has substantially the same configuration and function as the above-described embodiment, but is different in that the thermal battery cutoff element 16 and the fuse 51 are connected in series as the protection element.

That is, in the third modification, the thermal battery cutoff element 16 and the fuse 51 are connected in series to the positive electrode lead 13 connected to each wound electrode element 11. The branches of each positive electrode lead 13 are integrated into one positive electrode lead 13, and are electrically connected to the positive electrode terminal 15 to be electrically connected.

Also in the third modification, as in the above-described embodiment, a large number of spirally wound electrode elements 11 are connected in parallel and efficiently housed in the battery container portion 31, so that the electrodes of the entire battery are provided. The surface area of (positive electrode and negative electrode) becomes very large. Therefore, since the battery as a whole has a large energy density, it is possible to efficiently output.

As a result, the power density per unit weight and unit volume of the battery is significantly increased, and the battery performance can be improved.

Further, as in the above embodiment, the output lead of each spirally wound electrode element 11 is connected in series with the thermal battery cutoff element 16 and the fuse as a protective element. Further, the high temperature is suppressed, and as a result, the temperature of the entire battery is suppressed within the allowable range.

Therefore, it is possible to surely suppress the heat generation inside the battery during use, which is a big problem of the conventional non-aqueous electrolyte secondary battery, and to further improve the battery performance (energy density, power density, cycle characteristics, etc.). It is possible to prevent deterioration.

[0051]

According to the non-aqueous electrolyte secondary battery of the present invention, a plurality of parallel-connected positive electrode and negative electrode are wound with a separator interposed therebetween, and a non-aqueous solvent. The non-aqueous electrolyte solution in which the electrolyte is dissolved is housed in the same battery container, and the output lead of each wound electrode element is connected with the protective element, and the battery container internal pressure rises abnormally in the battery container. Since it is configured with a safety valve that is opened according to
It is possible to easily and inexpensively realize a large capacity, suppress excessive heat generation inside the battery, increase the output density per unit weight and unit volume, and further significantly reduce the manufacturing cost. It is possible to improve the yield.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing the structure of a non-aqueous electrolyte secondary battery according to an example of the present invention.

FIG. 2 is a cross-sectional view schematically showing an electrode portion that is a constituent element of the non-aqueous electrolyte secondary battery according to this example.

FIG. 3 is a perspective view schematically showing a heat-sensitive battery blocking element which is a protection element for a non-aqueous electrolyte secondary battery according to an example of the present invention.

FIG. 4 is a characteristic diagram showing electric resistance and temperature characteristics of the thermal battery cutoff element.

FIG. 5 is a perspective view schematically showing a first modified example of the non-aqueous electrolyte secondary battery according to the example of the present invention.

FIG. 6 is a perspective view schematically showing a second modified example of the non-aqueous electrolyte secondary battery according to the example of the present invention.

FIG. 7 is a perspective view schematically showing a third modified example of the non-aqueous electrolyte secondary battery according to the example of the present invention.

FIG. 8 is a cross-sectional view schematically showing the structure of a conventional non-aqueous electrolyte secondary battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electrode part 2 ... Upper lid part 3, 31 ... Battery container part 11 ... Winding electrode element 16 ... Thermal battery cutoff element 51 ... Fuse

Claims (3)

[Claims] 1. A non-aqueous solution in which a plurality of spirally wound electrode elements in which a positive electrode and a negative electrode are wound with a separator interposed therebetween are housed in the same battery container and connected in parallel, and an electrolyte is dissolved in a non-aqueous solvent. It is characterized in that an electrolytic solution is injected, a protective element is coupled to the lead of each wound electrode element, and the battery container has a safety valve that is opened according to an abnormal rise in the internal pressure of the battery container. Non-aqueous electrolyte secondary battery. 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the protection element is a thermal battery blocking element and / or a fuse. 3. The non-aqueous electrolyte secondary battery according to claim 1, wherein a heat-sensitive battery cutoff element and a fuse are connected in series as a protection element.