JP2003346774A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery that does not have few failure (breakage, airtightness defect) of the terminal part. <P>SOLUTION: The battery comprises a battery container, a generating element, an auxiliary terminal, a connecting conductor, an outside terminal, and an outside terminal fixing means. The auxiliary terminal 3 has conductance with the generating element 1 in the battery and is fixed and connected to the connecting conductor 8 at the outside of the battery. The connecting conductor 8 connects the auxiliary terminal 3 and the outside terminal 9, and the outside terminal fixing means fixes the connecting means with an outside equipment to the outside terminal 9. When the outside terminal fixing means is fixed with play to the outside terminal, the outside terminal is supported by the connecting conductor with play, and when the outside terminal fixing means is fixed, the connecting conductor and the outside terminal are fixedly connected. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a battery.

[0002]

2. Description of the Related Art FIG. 1 is an assembled perspective view showing a connection structure between a power generating element and a terminal of a large-sized lithium ion secondary battery used for an electric vehicle or the like.

In this lithium ion secondary battery, four long cylindrical power generating elements 1 are closely arranged and connected in parallel. The four power generating elements 1 are arranged in close contact with each other so that the flat side surfaces of the long cylindrical shape are in contact with each other.
Is arranged. Each of the current collectors 2 is a horizontally disposed metal plate having an approximately isosceles triangle shape, and has eight elongated connection portions 2a protruding downward from the bottom of the triangle. The current collecting connector 2 includes four power generating elements 1
, Respectively, so that the connecting portions 2a are arranged on the end faces of these power generating elements 1. Also, two connecting portions 2 a are arranged on each end face of each power generating element 1. Here, positive and negative metal foils 1a are wound around the end surfaces of the power generating elements 1 so as to protrude into an elongated cylindrical shape. Then, the two connecting portions 2a arranged for each power generating element 1 are respectively arranged outside the bundle of the metal foils divided into right and left.

[0004] In this way, the connecting portion 2a of the current collector 2 is connected.
Is arranged, the bundle of the metal foils of the positive electrode 1a and the negative electrode 1b is sandwiched by the sandwiching plate 4 together with each connecting portion 2a. The holding plate 4 is obtained by folding a strip-shaped metal plate into two along the longitudinal direction. Then, by performing ultrasonic welding from both sides of these holding plates 4, the connection portion 2 a of the current collector 2 sandwiched between the holding plates 4 and the bundle of the metal foils of the positive electrode 1 a and the negative electrode 1 b are joined. Weld.

The approximately isosceles triangular portion of the positive / negative current collector 2 disposed above both ends of the power generating element 1 is shown in FIG.
As shown in the figure, the rectangular lid plate 6 is attached to both sides of the lower surface of the rectangular lid plate 6 via the insulating sealing material 5. The cover plate 6 is made of a metal plate, and the auxiliary terminals 3 are arranged on both sides of the upper surface via another insulating sealing material 7. The lower ends of these auxiliary terminals 3 penetrate the cover plate 6, and are connected and fixed by virtue of crimping to the vicinity of the approximately isosceles triangular vertex of each current collector 2.
The upper ends of the auxiliary terminals 3 are connected and fixed to the connecting conductors 8 that lock the external terminals 9 disposed on the insulating sealing material 7 by caulking.

The insulating sealing materials 5 and 7 are arranged above and below the cover plate 6 to insulate and seal between the current collector 2, the auxiliary terminal 3, the connecting conductor 8, the external terminal 9 and the cover plate 6. It is a resin molded plate. A concave portion 9a for the pedestal 9b for the external terminal 9 is formed in the insulating sealing material 7, and the pedestal 9b of the external terminal 9 is fitted therein and is pressed down by the connection conductor 8, so that the external terminal 9 Is fixedly held in the battery. Although the external terminals 9 are generally bolt-shaped, they are not necessarily limited to bolt-shaped ones.

The four power generating elements 1 are housed in a metal battery container body (not shown), and a lid plate 6 is fitted into an upper end opening of the battery container body and fixed by welding.
Then, a non-aqueous electrolyte is filled in the battery container body to form a lithium ion secondary battery.

[0008]

However, in the battery having the above-mentioned terminal portion, when a connection wire for connecting the external device and the battery is attached to the external terminal and tightened with a nut or the like, the tightening is performed. The torque is transmitted directly to the connecting conductor, and a shear stress is applied to the auxiliary terminal. When the tightening and removing operations of the external terminals are repeated, there is a problem that the auxiliary terminals are damaged or poor airtightness occurs.

The present invention has been made to solve such a problem, and comprises a battery container, a power generating element, an auxiliary terminal, a connecting conductor, an external terminal, and an external terminal fixing means, wherein the auxiliary terminal generates power inside the battery. An object of the present invention is to reduce defects (breakage, poor airtightness) in an auxiliary terminal portion of a battery having continuity with elements and being fixedly connected to a connection conductor outside the battery and having an external terminal and an auxiliary terminal connected by the connection conductor. I do.

[0010]

According to a first aspect of the present invention, a battery is provided.
A battery case, a power generation element, an auxiliary terminal, a connection conductor, an external terminal, and an external terminal fixing means are provided. The auxiliary terminal has conductivity with the power generation element inside the battery and is for fixing and connecting the connection conductor outside the battery. The connecting conductor is for connecting the auxiliary terminal and the external terminal, and the external terminal fixing means is for fixing the connecting means to the external device to the external terminal, and the external terminal fixing means is for the external terminal. The external terminal is supported with play by the connection conductor when loosely attached, and the connection conductor and the external terminal are fixedly connected when the external terminal fixing means is fixed. I do.

According to the present invention, in a state where the external terminal fixing means is not fixed, the external terminal is supported with play by the connection conductor, so that not only the external terminal is not separated and lost from the battery. In addition, the tightening torque for fixing the connecting means to the external device does not transmit to the auxiliary terminal through the connecting conductor. When the external terminal fixing means is in the fixed state, the connection conductor and the external terminal are fixedly connected, so that good electrical continuity between the external terminal and the power generating element can be maintained. Therefore, even when attachment / detachment of the connection means to / from the external device is repeated, the auxiliary terminal is not damaged or the airtightness is not reduced, and a battery having a highly reliable terminal portion is provided.

The battery container is a general term for a battery container body and a cover plate for closing an opening of the battery container body.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

In the present embodiment, a large-sized lithium ion secondary battery used for an electric vehicle or the like will be described as in the conventional example. As shown in FIG. 1, this lithium-ion secondary battery has four long cylindrical power generating elements 1 shown in FIG. In each power generating element 1, the aluminum foil at the side end of the positive electrode 1a protrudes from one end surface of the long cylindrical shape, and the copper foil at the side end of the negative electrode 1b protrudes from the other end surface.

The four power generating elements 1 are arranged in close contact with each other so that the flat side surfaces of the long cylindrical shape are in contact with each other. Is arranged. As for the current collection connector 2, the one arranged on one end face side of the power generation element 1 is made of an aluminum alloy plate, and the one arranged on the other end face side is made of a copper alloy plate.

The current collector 2 is formed of a metal plate having a relatively large thickness so that a large current at the time of high-rate discharge can sufficiently flow. Each of the current collectors 2 is a horizontally flat metal plate having a somewhat flat isosceles triangle shape, and eight elongated connection portions 2a project downward from the bottom of the triangle shape. ing.

These connecting portions 2a are formed by punching a metal plate of the current collecting connector 2 into an elongated metal plate by pressing, and bending the metal plate downward and by 90 °.
With a twist. Further, as shown in FIG. 2, a plurality of protrusions 2b protruding from one surface side of the metal plate are formed in these connection portions 2a.

The current collectors 2 are arranged above both ends of the four power generating elements 1, respectively, and the connecting portions 2 a are arranged on the end faces of these power generating elements 1. That is,
A current collector 2 made of an aluminum alloy plate is provided on an end surface of the power generating element 1 on the side where the aluminum foil protrudes from the positive electrode 1a.
Is arranged, and a current collector 2 made of a copper alloy plate is arranged on an end surface of the negative electrode 1 b on the side where the copper foil protrudes.

Further, two connecting portions 2 a are arranged on each end face of each power generating element 1. Here, since the aluminum foil of the positive electrode 1a or the copper foil of the negative electrode 1b is wound on the end face of each power generating element 1 and protruded into a long cylindrical shape, these metal foils are bundled in a straight line. The part is divided right and left around the winding axis.

Then, the two power generation elements 1
The connection portions 2a of the book are respectively arranged outside the bundle of the metal foils divided into right and left. As shown in FIG. 2, the two connecting portions 2a are twisted by 90 ° in directions opposite to each other so that the surface of the protruding portion 2b projects toward the inside, that is, the metal foil bundle side. Have been added.

In this manner, the connection portion 2a of the current collector 2
Is arranged, the bundle of the metal foils of the positive electrode 1a and the negative electrode 1b is sandwiched by the sandwiching plate 4 together with each connecting portion 2a. The holding plate 4 is formed by folding a strip-shaped metal plate in two along the longitudinal direction. In the case of the connection portion 2a on the positive electrode 1a side, an aluminum alloy plate is used, and the connection portion 2a on the negative electrode 1b side is used.
In this case, a copper alloy plate is used. Then, by performing ultrasonic welding from both sides of these holding plates 4, the connection portion 2 a of the current collector 2 sandwiched between the holding plates 4 and the bundle of the metal foils of the positive electrode 1 a and the negative electrode 1 b are joined. Weld.

At this time, since the holding plate 4 is used only for welding and connecting the connecting portion 2a and the bundle of metal foils, a metal plate which is thin enough to enable optimal ultrasonic welding is used. Can be used. In addition, the connecting portion 2a includes:
Since the convex portion 2b is formed on the surface overlapping with the metal foil bundle of the positive electrode 1a and the negative electrode 1b, the metal foil bundle receives the ultrasonic energy intensively at the convex portion 2b so as to be surely welded. become.

The substantially isosceles triangular portion of the positive / negative current collector 2 disposed above both ends of the power generating element 1 is shown in FIG.
As shown in the figure, the rectangular lid plate 6 is attached to both sides of the lower surface of the rectangular lid plate 6 via the insulating sealing material 5. The cover plate 6 is made of a stainless steel plate, and the positive and negative auxiliary terminals 3 are arranged on both sides of the upper surface via another insulating sealing material 7.

The lower ends of these auxiliary terminals 3 penetrate the cover plate 6 and are fixedly connected by caulking to the vicinity of the approximately isosceles triangular apex of each current collector 2. Also,
The upper ends of these auxiliary terminals 3 are connected and fixed by caulking to connection conductors 8 which lock external terminals 9 arranged on insulating sealing material 7. These auxiliary terminals 3 are made of an aluminum alloy for the current collector 2 made of an aluminum alloy plate, and made of a copper alloy for the current collector 2 made of a copper alloy plate.

However, since the connection conductor 8 and the external terminal 9 do not come into contact with the electrolytic solution, a steel or iron alloy having higher strength than these aluminum alloys or copper alloys is used. The insulating sealing materials 5 and 7 are arranged above and below the lid plate 6,
It is a resin molded plate that insulates and seals between the current collector connector 2, the auxiliary terminal 3, the connection conductor 8, the external terminal 9 and the cover plate 6.

FIG. 4 is a cross-sectional view schematically showing the relationship between the external terminal fixing means, the external terminal and the connecting means, wherein 9 is an external terminal, 10 is an external terminal fixing means, 8 is a connecting conductor, and 7 is an insulating member. It is a sealing material. In this example, the external terminal 9 is constituted by a bolt terminal having a locking portion 9b, and the external terminal fixing means is constituted by a nut which can be screwed to the bolt terminal. 9a is a recess for a bolt terminal formed in the insulating sealing material 7.

In this type of conventional battery, the bolt terminal locking portion 9b and the bolt terminal recess 9a are formed in a shape and dimensional relationship that can be fitted, and the bolt terminal locking portion 9b is connected to the connection conductor 8 Because it was fixed so that it could not move,
When a connection wire, a ring terminal, or the like for connecting an external device and a battery is attached to an external terminal and tightened with a nut or the like, the tightening torque is directly transmitted to the connection conductor, and shear stress is applied to the auxiliary terminal. When the tightening and removing operations of the external terminals are repeatedly performed, the auxiliary terminals are damaged or poor airtightness occurs.

In the battery of the present invention, as shown in FIG. 9A, when the external terminal fixing means 10 is loosely attached (when it is loosely attached), the external terminal 9 has play with the connection conductor 8. 9B, the connection conductor 8 and the external terminal 9 are fixedly connected when the external terminal fixing means 10 is tightened (fixed) as shown in FIG. 9B. Connecting wires and the like (not shown) for connecting the external device and the battery are connected to the external terminals 9.
Even if the terminal is tightened with the nut 10 or the like, the tightening torque is not directly transmitted to the connection conductor 8 and no shear stress is applied to the auxiliary terminal. The terminal may be damaged,
Poor airtightness does not occur.

Further, according to the lithium ion secondary battery having the above-described structure, the charging / discharging current between the positive electrode 1a or the negative electrode 1b of each power generating element 1 and the auxiliary terminal 3 is limited to the current collector composed of a thick metal plate. Since it flows through the connection portion 2a of the connection body 2,
A sufficiently large charge / discharge current can flow. Moreover, the bundle of the metal foils of the positive electrode 1a and the negative electrode 1b of each power generating element 1 is ultrasonically welded to the connecting portion 2a via the sandwiching plate 4 made of a somewhat thin metal plate. Is not easily peeled off.

Further, since the energy due to the ultrasonic welding can be concentrated on the convex portion 2b of the connecting portion 2a,
The bundle of metal foil can be more reliably and firmly welded to the connection portion 2a. Furthermore, each connection part 2a is arranged on the side of the bundle of metal foils of the positive electrode 1a and the negative electrode 1b protruding from the end face of the power generation element 1, and these connection parts 2a and the bundle of metal foil are sequentially placed between the holding plates 4. It is good to put it between
The assembly work can be performed more easily than the work of inserting the bundle of these metal foils into the corrugated concave portions of the current collector 2 as in the related art.

Further, according to the lithium ion secondary battery, the auxiliary terminal 3 made of an aluminum alloy or a copper alloy is fixedly connected to the connection conductor 8 made of a steel or iron alloy or the like, and the connection with an external circuit is established. Since the connection is performed via the external terminal 9 locked to the connection conductor 8, it is not necessary to directly screw and connect the auxiliary terminal 3 made of aluminum alloy or copper alloy having weak strength. There is no fear that the auxiliary terminal 3 is damaged or the auxiliary terminal 3 is deformed by vibration or impact.

In the above embodiment, the case where the connecting portion 2a and the metal foil of the positive electrode 1a or the negative electrode 1b are welded between the holding plates 4 by ultrasonic welding has been described. Welding can also be performed. Further, instead of such welding, the connection portion 2a and the metal foil of the positive electrode 1a or the negative electrode 1b can be pressed by pressing with a strong force from the outside of the holding plate 4. In this case, unlike the case of welding, it is necessary to use a metal plate having a relatively large thickness, so that the connecting portion 2a and the metal foil can be securely pressed and held during this time.

Further, in the above embodiment, the case where the convex portion 2b is formed on the connection portion 2a has been described. However, a similar convex portion can be formed on the holding plate 4. However, even when such a convex portion 2b is not formed at all, the metal foil can be reliably welded or pressed.

In the above embodiment, the case where the metal foils of the positive electrode 1a and the negative electrode 1b are arranged only on one side of the connecting portion 2a has been described. It can also be sandwiched between. Further, in the above-described embodiment, two end faces of each power generation element 1 are provided.
Although the two connecting portions 2a are arranged, the number of the connecting portions 2a is not limited. For example, one connecting portion 2a may be arranged on one end face of each power generating element 1, or a metal foil protruding from the end faces of two power generating elements 1 adjacent to this one connecting portion 2a may be used. Common welding or crimping is also possible.

In the above embodiment, the lithium ion secondary battery has been described, but the type of the battery is not limited. Incidentally, the basic configuration of the lithium ion battery according to the present invention can be as follows.

First, titanium disulfide is applied to the positive electrode active material.
Lithium cobalt composite oxide, spinel type lithium
Manganese oxide, vanadium pentoxide and molybdenum trioxide
Various things such as ribden are available, but
Also, lithium cobalt composite oxide (Li_xCoO₂)
And spinel lithium manganese oxide (Li_xMn ₂
O₄) Is 4V (Li / Li⁺) More than noble electricity
Charge / discharge at high speed, high discharge
A battery having an electric voltage can be realized.

The positive electrode has a current collector of 10 to 30 μm.
A thick aluminum foil is public, and an active material layer is generally applied on both surfaces of the above-mentioned aggregate. The active material layer has a thickness of 50 to 150 μm (per one side) and a density of 1.8. ~
Those having a porosity of 3.0 g / cc and a porosity of 25 to 45% are preferable in terms of life performance and charge / discharge characteristics.

As the negative electrode, various types of materials such as lithium metal and a Li-Al alloy or a carbon material capable of inserting and extracting lithium can be used. Among them, a carbon material is highly safe and has a high cycle life. There is an advantage that a long-life battery can be obtained. In this case, the current collector is 1
A copper foil having a thickness of 0 to 20 μm is preferable, and the active material layer has a thickness of 45 to 125 μm (per one side) and a density of 1.15 to 2.
Those having 5 g / cc and porosity of 25 to 45% are preferable in terms of life performance and charge / discharge characteristics.

As the electrolytic solution, propylene carbonate, ethylene carbonate, 7-butyrolactone,
A mixture of a high dielectric constant solvent such as sulfolane and a low-viscosity solvent such as 1,2-dimethoxyethane, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate is mixed with lithium perchlorate, lithium trifluoromethanesulfonate, Lithium fluorophosphate or the like is added. Instead of these liquid systems,
There are also all-solid electrolytes, gel electrolytes, and combinations of these with liquid electrolytes.

The electrode can be manufactured, for example, by applying a slurry prepared by mixing an active material, a binder and a solvent onto a metal foil. Fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene are excellent as binders in terms of oxidation-reduction resistance and electrolyte resistance, but among them, polyvinylidene fluoride soluble in organic solvents can be easily slurried. Is most widely used at present. The amount is 2 to 6% by weight for the positive electrode, and 6 to 1 for the negative electrode.
It is preferably 0% by weight.

The separator has a thickness of 20 to 60 μm.
Although a porous resin film is suitable, a polymer electrolyte membrane can also be used.

[0042]

As is apparent from the above description, since the positive and negative terminals of the battery of the present invention are located outside the positive and negative connection conductors, the connecting rod is shortened when connecting to an external device or another similar battery. be able to. Further, since the distance between the positive and negative terminals can be widened, various mounting methods can be adopted when mounting the battery on an automobile or the like.

[Brief description of the drawings]

FIG. 1 is an assembled perspective view showing a connection structure between a power generation element and a terminal of a lithium ion secondary battery.

FIG. 2 is a cross-sectional view showing a connection portion of a current collector and a metal foil of a positive electrode and a negative electrode of a power generation element sandwiched between holding plates.

FIG. 3 is a diagram showing a conventional example.

FIG. 4 is a diagram showing one embodiment of the present invention.

FIG. 5 is an assembled perspective view showing the structure of a power generating element.

[Explanation of symbols]

1 Power generation element 1d aluminum foil 1e Copper foil 1f insulation 2 Current collector 2a Connection part 3 terminals

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takeshi Shimozono             Kyoto, Minami-ku, Kyoto             No. 1 Inside Japan Battery Co., Ltd. (72) Inventor Kunyo Munaga             Kyoto, Minami-ku, Kyoto             No. 1 Inside Japan Battery Co., Ltd. F term (reference) 5H022 AA09 AA18 AA19 BB02 BB03                       CC12 CC13 CC16 CC22

Claims (1)

[Claims] 1. A battery comprising a battery container, a power generating element, an auxiliary terminal, a connecting conductor, an external terminal and an external terminal fixing means, wherein the auxiliary terminal has continuity with the power generating element inside the battery and a connecting conductor outside the battery. The connection conductor is for connecting the auxiliary terminal to the external terminal, and the external terminal fixing means is for fixing the connection means to the external device to the external terminal. When the external terminal fixing means is loosely attached to the external terminal, the external terminal is supported with play by the connection conductor, and when the external terminal fixing means is fixed, the connection conductor and the external terminal are fixedly connected. A battery comprising: a battery;