JP2002279969A - Battery and on-vehicle secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-weight and small on-vehicle secondary battery, especially one having a plurality of it contained in an outer covering container. SOLUTION: This battery L comprises a battery constitution 1, having a positive electrode current collector 111 and a negative electrode current collector 121, a flexible battery container 3 in which the construction is contained, a positive electrode terminal layer 41 formed on a surface of the container and a negative electrode terminal layer 42 and has the positive electrode current collector and the positive electrode terminal layer, as well as the negative electrode current collector and the negative electrode terminal layer connected electrically. Especially it is preferable that the battery container be a flat plate container made of an impermeable film, such as aluminum laminated film and a positive electrode terminal layer is formed on one face of the container and the negative electrode terminal layer on the other face. A plurality of the battery is contained in the outer covering container made of resin and the positive electrode terminal layer of one battery contacts the negative electrode terminal layer of the other adjoining battery for connecting them in series, and thereby the light and small on-vehicle secondary battery can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to batteries and secondary batteries for vehicles. More specifically, the present invention relates to a battery having a specific electrode terminal structure and thereby being sufficiently reduced in size, and a lightweight and small in-vehicle secondary battery in which a plurality of secondary batteries are housed in an outer container.

[0002]

2. Description of the Related Art A battery structure in which a positive electrode current collector having a positive electrode active material layer on the surface, a separator, and a negative electrode current collector having a negative electrode active material layer on the surface are laminated, and positive and negative electrode terminals are attached to this. BACKGROUND ART A battery in which a body is contained in a container is used in many applications. The battery structure is wound or laminated, and usually housed in a metal container, and is provided as a cylindrical or square battery. On the other hand, in order to make the battery lighter and thinner, a battery in which a laminated battery structure is housed in a flexible container such as an aluminum laminated film has been proposed.

[0003]

A battery in which a battery structure is accommodated in a flexible container can be used as it is, but its use is sometimes limited because its shape is not maintained. In such a battery, the respective positive and negative electrode lead terminals are usually taken out from the fused portion at the edge of the container. However, as shown in FIG. 6, the lead terminal take-out portion has a considerable length, from which the lead terminal extends further outward. Therefore, the sum of the terminal take-out part and the lead terminal is often １ ／ to ３ of the dimension of the container body in which the battery structure is stored. When such a battery is actually used, there is a problem since a space that is not so meaningful is required for lead terminals and the like.

Further, the electromotive force of these batteries is usually about several volts, depending on the type of electrolyte and the like.
When used as an in-vehicle secondary battery requiring a rated voltage of 2 to 14 V, it is necessary to connect 6 to 7 batteries in series. In this case, since the battery itself cannot maintain its shape, it must be housed in an outer container made of resin or the like. And since each battery has a terminal take-out part and a lead terminal of a considerable length, it requires much of the upper space of the outer container for this lead terminal and the like,
It is not possible to provide a sufficiently miniaturized battery for use in vehicles.

[0005] The present invention solves the above-mentioned conventional problems, in which the battery structure is housed in a flexible container, and is light in weight.
Another object of the present invention is to provide a battery which is thin and has no lead terminal take-out portion and lead terminal projecting to the side of the container at all. In particular, it is another object of the present invention to provide a lightweight and small in-vehicle secondary battery in which a plurality of batteries are housed in an outer container and connected in series.

[0006]

According to a first aspect of the present invention, a battery is provided.
A battery structure having a positive electrode current collector and a negative electrode current collector, a flexible battery container in which the battery structure is housed, and a positive electrode terminal layer and a negative electrode terminal layer formed on the surface of the battery container A battery, wherein the positive electrode current collector and the positive electrode terminal layer, and the negative electrode current collector and the negative electrode terminal layer are electrically connected to each other.

The type of battery having this configuration is not particularly limited, and examples thereof include secondary batteries such as nickel cadmium batteries, nickel hydrogen batteries, and lithium ion batteries. In particular, as set forth in claim 2, the battery container is a flat container made of an impermeable film, and a positive electrode terminal layer is formed on one surface of the flat container and a negative electrode terminal layer is formed on the other surface. preferable. By forming a battery having such a flat shape and having positive and negative electrode terminal layers on one surface and the other surface, a plurality of batteries are connected in series to easily form a battery having a higher output voltage. be able to. In addition, the above-mentioned "impermeable" means that it is difficult for gas and liquid to permeate, and in particular, in the case of a lithium ion battery or the like, it means that entry of water vapor in the atmosphere into the battery is suppressed or prevented. .

According to a third aspect of the present invention, there is provided a vehicle-mounted secondary battery comprising: an outer container; and a plurality of secondary batteries housed in the outer container. Structure having a body and a negative electrode current collector, a flat battery container including an impermeable film in which the battery structure is housed, a positive electrode terminal layer formed on one surface of the battery container, and the battery container A negative electrode terminal layer formed on the other surface, and a positive electrode terminal layer of one secondary battery of adjacent secondary batteries among the plurality of secondary batteries, and a negative electrode of the other secondary battery. A terminal layer is in contact with the battery, and the plurality of secondary batteries are connected in series.

In this vehicle-mounted secondary battery, positive and negative electrode terminal layers are formed on both sides of a flat battery container.
Then, by bringing these electrode terminal layers into contact with each other, adjacent batteries can be easily connected in series. Therefore, a lighter and smaller in-vehicle secondary battery can be easily formed as compared with a battery in which lead terminals are taken out from the container edge as in the related art.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described more specifically with reference to examples based on lithium ion secondary batteries. (1) Structure of Lithium-Ion Secondary Battery Battery Structure FIG. 1 is a longitudinal sectional view of a battery structure 1 constituting a stacked lithium-ion battery. The positive electrode sheet 11 is formed by a positive electrode current collector 111 and a positive electrode active material layer 112 provided on one surface thereof. Further, the negative electrode sheet 12 is formed by a negative electrode current collector 121 and a negative electrode active material layer 122 provided on one surface thereof. Further, the other surfaces of the positive electrode current collector 111 and the negative electrode current collector 121 are respectively laminated on one surface and the other surface of the separator 2, thereby forming the battery assembly 1.

FIG. 2 shows one side and the other side of each of the positive and negative electrode terminal layers 4.
It is a longitudinal cross-sectional view of the impermeable film 3 'which becomes a battery container in which 1 and 42 were formed. Both ends in one direction of the cylindrical impermeable film 3 'serving as a battery container are open. Then, the battery assembly 1 can be housed inside from any open end. Openings 31 ′ and 32 ′ are formed on one surface and the other surface of the impermeable film 3 ′, respectively. The positive and negative electrode terminal layers 41 and 42 cover at least these openings 31 ′ and 32 ′. Are formed.

The openings 31 ′ and 32 ′ are respectively provided with the positive electrode current collector 111 and the negative electrode current collector 121 of the battery structure 1 housed inside the impermeable film 3 ′, the positive electrode terminal layer 41 and the negative electrode terminal The layer 42 is formed so as to be in contact with each other and to make an electrical connection. Each opening may be formed at any position on the surface of the impermeable film 3 ′ as long as it is a portion corresponding to each of the positive electrode current collector 111 and the negative electrode current collector 121. Is not particularly limited. In addition, the positive and negative electrode terminal layers 41, 42
Have a positive electrode current collector 111 and a negative electrode current collector 12
It is sufficient that they are in contact with each other and are connected to each other, and the position to be formed and its area and shape are not particularly limited.

In particular, when one battery is used alone, the positive and negative electrode terminal layers 41 and 42 can be formed at desired positions depending on the use of the battery, etc. Not limited at all.

On the other hand, when a plurality of batteries are connected in series as in the secondary battery for vehicle according to the third aspect, one positive electrode terminal layer and the other negative electrode terminal layer of adjacent batteries are connected to each other. Electrical connection is required. Also, in order to make the in-vehicle secondary battery or the like smaller and not to form an unnecessary space, it is necessary to use batteries having substantially the same shape and size in a planar direction and arrange a plurality of them so as to be in contact with each other. In addition, it is preferable to arrange them so that the total volume is minimized. To this end, the positive and negative electrode terminal layers 41 and 42 of the adjacent batteries are used.
Are preferably formed at substantially the same position in the plane direction of each battery. In particular, these electrode terminal layers 4
When the batteries 1 and 42 are formed at least in the vicinity of the central portion in the planar direction of the batteries, the batteries can be easily electrically connected to each other by pressing the batteries in the lateral direction. This is more preferable because the reliability of the connection can be improved.

Lithium ion secondary battery FIG. 3 shows a longitudinal section of a lithium ion secondary battery L in which a battery structure is housed in an impermeable film on which positive and negative electrode terminal layers 41 and 42 are formed. FIG.
FIG. 4 is a perspective view showing the appearance of the battery L.
The battery structure is housed inside the impermeable film, and the open end is heat-sealed to form the battery container 3. Further, the positive electrode current collector 111 included in the battery structure 1 and the positive electrode terminal layer 41 formed on one surface of the battery container 3 are joined and connected at the opening 31 ′. On the other hand, the negative electrode current collector 1
21 and the negative electrode terminal layer 42 are joined and connected at the opening 32 '. The separator 2 is impregnated with an electrolytic solution in which an electrolyte is dissolved.

(2) Manufacture of Lithium Ion Secondary Battery Manufacture of Battery Assembly In the battery assembly 1 shown in FIG.
Is formed by providing a positive electrode active material layer 112 on one surface of a positive electrode current collector 111 made of a metal foil. The positive electrode active material layer 112, after applying a paste containing a positive electrode active material, a conductive agent, a binder, and the like, to one surface of the positive electrode current collector 111 by a comma coater method, a die coater method, or the like,
It is formed by drying and pressing. As the metal foil, an aluminum foil, a nickel foil, a copper foil, or the like can be used. Further, as the positive electrode active material, LiCo
Oxides containing lithium and other metal elements such as O ₂ , LiMn ₂ O ₄ , LiNiO ₂ , and LiFeO ₂ can be used. Furthermore, carbon black, black smoke, pitch coke, and the like can be used as the conductive agent, and polyvinylidene fluoride, polytetrafluoroethylene, and the like can be used as the binder.

The negative electrode sheet 2 is formed by providing a negative electrode active material layer 122 on one surface of a negative electrode current collector 121 made of a metal foil. The negative electrode active material layer 122 is formed in the same manner as the positive electrode active material layer using a paste containing a negative electrode active material, a conductive agent, a binder, and the like. Examples of the negative electrode active material include carbon-based materials such as amorphous carbon and graphite, and oxides such as Si, Sn and In, and Sn and I
An alloy of n and the like and Li can be used. Also,
As the metal foil, the same one as in the case of the positive electrode current collector 111 can be used, and as the conductive agent and the binder, the same one as in the case of the positive electrode current collector 111 can be used.

The other surface of each of the positive electrode current collector 111 and the negative electrode current collector 121 is laminated on one surface and the other surface of the separator 2 made of a resin film or the like having fine holes.
As a resin film having micropores, a porous polyethylene film, a porous polypropylene film, or the like is frequently used. Here, when it is not possible to sufficiently fix each other simply by laminating both surfaces, it is also possible to join with polyvinylidene fluoride or the like as a binder.

The micropores of the separator 2 are impregnated with an electrolyte in which an electrolyte is dissolved. As a solvent for dissolving the electrolyte, ethylene carbonate, propylene carbonate, dimethyl carbonate, γ-butyrolactone, 1,2-dimethylethane, tetrahydrofuran,
An aprotic solvent such as 1,3-dioxane and methyl acetate can be used. These may be used alone or in combination of two or more.

As the electrolyte, LiPF₆, Li
BF_Four, LiCF_ThreeSO_Three, LiClO _Four, LiAsF₆,
LiSbF₆, LiC_FourF₉SO_Three, LiN (CF_ThreeSO_Two)
_Two, LiC (CF_ThreeSO_Two)_ThreeUse of lithium salt such as
Can be. Of these, LiPF₆, LiBF_FourBut
It is particularly frequently used. These may be used alone.
However, two or more kinds can be used in combination. Contained in electrolyte
The concentration of the electrolyte used is usually 0.05 to 10 mmol /
Liter, 0.1-5 mmol / l
Is preferred.

Preparation of an impermeable film having an electrode terminal layer formed on the surface The openings 31 'and 32' in the impermeable film 3 'to be a battery container shown in FIG. It is formed by a method such as punching using such as.
In this case, it is preferable to punch out two layers of the cylindrical impermeable film 3 'at the same time. In this way, the openings 31 'and 32' having the same shape can be formed at the same position in the plane direction on both surfaces of the impermeable film 3 ', and a plurality of batteries can be connected in series. When used, the electrical connection of each battery can be made easily and reliably.

The impervious film 3 ′ is hardly permeable to gas and liquid, or need not be substantially permeable.
The material and the like are not limited. A resin film (including an elastomer film made of a thermoplastic elastomer or the like) may be used as long as it has sufficient impermeability.
A laminated film in which a resin film 332 'is joined to 31' is preferable. As this laminated film, a so-called aluminum laminated film in which a polyethylene film or the like is laminated on an aluminum foil is particularly often used. If it is a polyethylene film, the edge can be firmly heat-sealed with this film as the inner surface, and the battery container 3 excellent in impermeability can be easily formed.

When the surface is made of aluminum foil, the strength may not be sufficient. In that case, it is preferable to use a three-layer laminated film in which a film having excellent mechanical strength such as a polyester film is further heat-sealed to an aluminum foil. With such a laminated film, the battery container 3 having excellent impermeability and sufficient strength can be obtained.

On both surfaces of the impermeable film 3 ', positive and negative electrode terminal layers 41 and 42 are formed. The electrode terminal layers 41 and 42 can be formed by joining a metal foil to a predetermined portion of the impermeable film 3 ′ with an adhesive layer 43 having conductivity. As the metal foil, an aluminum foil, a nickel foil, a copper foil, or the like can be used.

The battery assembly 1 produced at the substantially central portion in the length direction of the impermeable film 3 ′ having the electrode terminal layers 41 and 42 formed on the surface thereof, produced in the production of the lithium ion secondary battery. To store. Thereafter, the battery container 3 is formed by heat-sealing the open end of the impermeable film 3 '. In addition, the electrode terminal layer 4
1 and 42 and the positive electrode current collector 111 and the negative electrode current collector 121 are connected to the connection portions 5 in the openings 31 ′ and 32 ′, respectively.
1, 52 are electrically connected. This connection can be performed by an ultrasonic fusion method or the like. Furthermore, an adhesive layer having conductivity may be formed at a required portion, and may be joined and connected by pressing. In this way,
The lithium ion secondary battery shown in FIG. 3 is manufactured.

A plurality of the lithium ion secondary batteries L manufactured in the manufacture of the in-vehicle secondary battery are housed in an outer container 6 made of acrylonitrile-butadiene-styrene copolymer resin (ABS resin) or the like. Battery C. As shown in FIG. 5, this on-vehicle secondary battery C has, for example, seven lithium ion secondary batteries L in an outer container 6 and a positive electrode terminal layer 4 of each of the adjacent batteries.
1 and the negative electrode terminal layer 42 are arranged side by side so as to be in close contact with each other,
Connect in series. Then, the positive terminal layer 41 of the battery at one end is connected to the positive terminal 71, and the negative terminal layer 42 of the battery at the other end is connected to the negative terminal 72.

In the vehicle-mounted secondary battery C shown in FIG. 5, since the electrode terminals of each battery are formed on both sides of each battery as electrode terminal layers, almost no space is required above the inside of the outer container 6. do not do. Further, the container of the battery itself to be housed is made of a film and is lightweight. Therefore, the in-vehicle secondary battery C is lightweight and small, and is extremely useful for in-vehicle use.

On the other hand, in the conventional battery 8 shown in FIG. 6 using the battery container 3 made of a laminated film, the total of the terminal extraction portion 91 and the lead terminal 92 forming the electrode terminal portion 9 extracted from the edge portion. Length is 1/4 to 1 / of the battery body
It has a length of three. Therefore, for example, in a case where seven such batteries 8 are arranged side by side in an outer container 6 made of ABS resin or the like and accommodated therein, and the secondary battery C for vehicle mounting shown in FIG. Many spaces 10 for accommodating the terminal portions 9 are required. Therefore, although it is possible to reduce the weight, it is not possible to sufficiently reduce the size, and it cannot be said that the required characteristics for the vehicle-mounted battery are sufficiently satisfied.

[0029]

According to the first aspect of the invention, since the positive and negative electrode terminal layers are formed on the surface of the flexible battery container, the battery is lightweight and when a plurality of the battery terminals are used in series, The size can be easily reduced. In particular, as described in claim 2, in a battery in which positive and negative electrode terminal layers are formed on one side and the other side of a flat container made of an impermeable film, when a plurality of units are connected and used, It can be lighter and smaller.

Further, the vehicle-mounted secondary battery according to claim 3 is:
It has sufficient characteristics required for a vehicle-mounted battery such as light weight and small size.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a battery structure constituting a stacked lithium ion battery.

FIG. 2 is a vertical cross-sectional view of an impermeable film serving as a battery container in which positive and negative electrode terminal layers are formed on one surface and the other surface.

FIG. 3 is a longitudinal sectional view of a battery in which a battery structure is accommodated and formed in an impermeable film on which positive and negative electrode terminal layers are formed.

FIG. 4 is a perspective view showing the appearance of the battery of FIG.

FIG. 5 is a schematic view of a vehicle-mounted battery according to an embodiment.

FIG. 6 is a schematic view of a conventional battery using a container made of a laminated film.

7 is a schematic view of a vehicle-mounted secondary battery in which the conventional battery of FIG. 6 is housed in an outer container.

[Explanation of symbols]

L: lithium ion secondary battery, C: vehicle-mounted secondary battery,
DESCRIPTION OF SYMBOLS 1; Battery structure, 11; Positive electrode sheet, 111; Positive electrode collector, 112; Positive electrode active material layer, 12;
1, negative electrode current collector, 122; negative electrode active material layer, 2; separator, 3 '; impermeable film, 31', 32 '; opening, 331'; metal foil, 332 '; resin film, 3;
Battery container, 31; heat-sealed portion, 41; positive electrode terminal layer, 42;
Negative electrode terminal layer, 43; adhesive layer, 51, 52;
6; Outer container, 71; Positive terminal, 72; Negative terminal, 8;
Conventional battery, 9; electrode terminal portion, 91; terminal extraction portion,
92; lead terminal, 10; space.

Claims (3)

[Claims] 1. A battery structure having a positive electrode current collector and a negative electrode current collector, a flexible battery container containing the battery structure, a positive electrode terminal layer and a negative electrode terminal formed on the surface of the battery container. A battery comprising: the positive electrode current collector and the positive electrode terminal layer; and the negative electrode current collector and the negative electrode terminal layer
Are electrically connected to each other. 2. The battery container according to claim 1, wherein the battery container is a flat container made of an impermeable film, wherein the positive electrode terminal layer is formed on one surface of the flat container and the negative electrode terminal layer is formed on the other surface. Batteries. 3. A vehicle-mounted secondary battery including an outer container and a plurality of secondary batteries housed in the outer container, wherein the secondary battery has a battery structure having a positive electrode current collector and a negative electrode current collector. Body, a flat battery container made of an impermeable film in which the battery structure is housed, a positive electrode terminal layer formed on one surface of the battery container, and a negative electrode terminal layer formed on the other surface of the battery container And the positive electrode terminal layer of one of the secondary batteries adjacent to the secondary battery among the plurality of secondary batteries, and the negative electrode terminal layer of the other secondary battery are in contact with each other. An in-vehicle secondary battery, wherein the secondary batteries are connected in series.