JPH10112330A - Cylindrical battery and battery assembly using the battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To release heat and gas certainly, by attaching a positive electrode current collecting plate which has electrically connected plural holes on one end of a unit cell, and by attaching a negative electrode current collecting plate on the other end of it. SOLUTION: A short cylindrical battery (D) is structured, by inserting a unit cell for power generation into a short cylindrical outside case 1 consisting of SUS and others, attaching on its upper side an upper lid 2 consisting of SUS or others which also plays the role of positive electrode terminals, and installing a bottom lid 4 as negative electrode terminal on its lower side. A cylindrical hollow core 3 which functions as a ventilation hole for cooling is installed on the bottom lid 4. Positive electrode active material is held on the outside of a band-shaped positive electrode current collector which consists of aluminum metal foils and others, negative electrode active material is held on the inside of negative electrode current collector which consists of copper metal foils and others, and they are shifted each other horizontally and winded. Drilling multiple small holes through the positive electrode current collector certainly releases heat and gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical battery and an assembled battery using the cylindrical battery, and more particularly to a cylindrical battery suitable for an electric vehicle and the like and an assembled battery using the cylindrical battery.

[0002]

2. Description of the Related Art FIG. 14 is an external perspective view of an example of an assembled battery B used as a primary battery for a power source of a conventional electric vehicle. As shown in FIG. 14, the battery pack B has a battery case 101 in which a large number of battery modules 102 are incorporated, and the battery modules 102 are connected by bus bars (connection terminals) 103 made of copper or the like.
A DC voltage of about 0 V is obtained. The bus bar 103 is connected to a terminal of the battery module 102 via a large hexagonal screw for connection.

In addition, for safety reasons such as prevention of electric shock,
Each battery module 102 is covered by a cover (not shown). However, the conventional battery pack requires a large number of heavy busbars and large hexagonal screws, so the total weight of the battery pack becomes large, and a large number of battery modules are required to obtain a high DC voltage. To assemble
Battery packs are bulky. Therefore, the weight energy density and the volume energy density of the battery pack are low, which is not preferable for a battery pack for electric vehicles.

When power is taken out from the battery pack, heat is generated (especially at the time of high output), but the cover cannot sufficiently release heat. Further, FIG.
As shown in (B), when the battery pack B is mounted on an electric vehicle, it is often mounted under the floor. In this case, since the battery pack B must be configured to be thin, the air circulation portion A for heat radiation becomes narrow, and it is difficult to secure a sufficient heat radiation route. As one of means for solving such inconvenience, a belt-like positive electrode current collector, a negative electrode current collector holding a positive electrode active material and a negative electrode active material are wound in a roll shape, and have a hollow hole in the center thereof. Cylindrical batteries have been proposed.

[0005]

However, even with this type of cylindrical battery, the heat generation as described above and how to discharge the gas generated inside the battery are important issues. Accordingly, an object of the present invention is to provide a cylindrical battery capable of reliably releasing and discharging heat and gas generated inside the battery, and an assembled battery using the cylindrical battery.

[0006]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a belt-like positive electrode current collector and a negative electrode current collector each holding a positive electrode active material and a negative electrode active material. Are wound in a roll shape while being shifted by a predetermined width in the width direction, and a unit cell for power generation having a hollow hole in the center thereof, and an electric endurance on one side end face of the wound unit cell. And a negative electrode current collector having a plurality of holes electrically connected to the other side end surface of the wound unit cell. And The invention according to claim 2 is characterized in that the connecting means of the positive electrode current collector plate and the negative electrode current collector plate to the side end faces of the unit cell is performed by brazing.

According to the first and second aspects of the present invention, the side end surfaces of the unit cells are electrically connected to the positive electrode current collector and the negative electrode current collector by, for example, brazing.
Thereby, power can be taken out from the positive electrode current collector and the negative electrode current collector. Further, a plurality of holes are formed in the positive electrode current collector plate and the negative electrode current collector plate, and the gas generated inside the unit cell is released from these holes.

According to a third aspect of the present invention, a hole is provided along the shifted side end surface of at least one of the wound positive electrode current collector and the negative electrode current collector. And According to the third aspect of the present invention, in addition to the holes provided in the positive electrode current collector and the negative electrode current collector, the holes are also generated inside the unit cell from the holes formed in the positive electrode current collector or the negative electrode current collector. Gas is released.

According to a fourth aspect of the present invention, there is provided a metal battery in which the cylindrical batteries according to any one of the first to third aspects are arranged in a matrix with their central holes directed vertically. A battery box is provided, and the battery pack box is provided with heat dissipating fins on a bottom surface and a lid surface. According to the fourth aspect of the invention, the heat generated in the cylindrical battery is discharged from the center hole, and the heat is efficiently dissipated from the fins on the bottom surface and the lid surface constituting the battery pack box.

[0010]

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

(1) First Embodiment FIG. 1 is an external perspective view of a cylindrical battery D of the present embodiment, and FIG. 2 is an exploded perspective view of the cylindrical battery D. As shown in FIGS. 1 and 2, the short cylindrical cylindrical battery D is SU
A unit cell S for power generation is inserted into a short cylindrical outer case 1 made of S or the like, and S serving as a + electrode terminal is also viewed from above.
An upper lid 2 made of US or the like is inserted, and a lower lid 4 made of SUS or the like also serving as a negative electrode terminal is inserted from below. A cylindrical hollow core 3 functioning as a cooling ventilation hole is vertically provided on the lower lid 4. The hollow core 3 is composed of an inner cylinder made of SUS, aluminum or the like, and an outer cylinder made of an insulating material such as PE or PP.

Next, the unit cell S will be described in detail. FIG. 3A is a perspective view showing a state where the positive electrode current collector 11, the negative electrode current collector 13, and the separator 15 constituting the unit cell S are wound into a roll paper shape (referred to as a roll body R). FIG. 3B is a conceptual diagram showing that the positive electrode current collector 11 and the negative electrode current collector 13 are wound while being shifted.

As shown in FIGS. 3A and 3B, a belt-like cathode active material 12 is held on the outer surface side of a belt-like cathode current collector 11 made of a metal foil such as aluminum. The negative electrode active material 14 is held in a band shape on the inner surface side of the band-shaped negative electrode current collector 13 made of a metal foil. The positive electrode current collector 11 and the negative electrode current collector 13 are wound so as to be shifted in the width direction, and a band-like material made of an insulator such as PE or PP is provided between the positive electrode current collector 11 and the negative electrode current collector 13. The separator 15 is interposed.

FIG. 4 shows a concept in which a disk-shaped positive current collector plate 21 made of SUS or the like and a negative electrode current collector plate 22 are connected to the upper and lower side end surfaces of the roll body R by brazing described below. FIG. Here, 11 a is the positive electrode current collector 11,
The end 13a of the positive electrode current collector where the positive electrode active material 12 is not held, and the end 13a of the negative electrode current collector 13 where the negative electrode active material 14 is not applied. That is, the portions indicated by 11a and 13a expose the above-mentioned metal foils of aluminum, copper, etc. forming the respective current collectors as they are.

[0015] Then, as shown in FIG.
The positive electrode current collector 21 is immersed in the solder 26 for several seconds while the positive electrode current collector 21 is temporarily fixed to the lower end surface (one end surface) of the roll body R. Then, the brazing 26 rises from the small holes 21a formed in the positive electrode current collecting plate 21 by capillary action, and the positive electrode current collector end 11a made of the above-described metal foil and the positive electrode current collecting plate 21 are brazed. Electrically connected. Since this brazing is a short time, all the small holes 21a are not closed by the brazing, and the soaking time is adjusted so that, for example, 50 to 80% of the small holes 21a remain open. Similarly, the negative electrode current collector plate 2 having a large number of small holes 22a formed on the other end surface of the roll body R
2 is brazed.

When the brazing of the positive and negative current collectors 21 and 22 is completed as described above, the unit cell S shown in FIG. 2 is completed. This unit cell S has the small holes 21a, 2a as described above.
Since about half of the 2a do not have a wax, even if a gas is generated inside the unit cell S, the gas is discharged to the outside from the small holes that are not brazed (the small holes that are not closed). Is done.

[First Modification] In the first embodiment, the case where the separator 15 is used has been shown (FIG. 3A,
(See (B)), this modification is a case where the separator 15 is not used. That is, as shown in FIGS. 6A and 6B,
The positive electrode active material 12 is applied on the upper surface of the positive electrode current collector 11, and a binder 31 made of an inorganic material such as silica is applied thereon to form an insulating layer.

[Second Modification] As shown in FIG. 7, a folded portion 16 may be provided along the lower surface of the positive electrode current collector 11. By doing so, the strength of the positive electrode current collector end 11a can be improved. It is needless to say that the negative electrode current collector 13 may be provided with a folded portion.

[Third Modification] In this modification, FIG.
As shown in (B), a half-cut punching hole 17, a small hole 18, and a waveform 19 are formed in a cut surface at the positive electrode current collector end 11 a of the positive electrode current collector 11. By forming the small holes in this way, as shown in FIG. 8C, not only the gas is discharged vertically from the holes formed in the positive and negative electrode current collector plates 21 and 22, but also the roll body is formed. Gas is also discharged in the left-right direction from the R hole or the like, so that degassing can be further improved.

(2) Second Embodiment This embodiment is an example in which a battery pack is constituted by the cylindrical battery D in consideration of heat radiation. FIG. 9A is a plan view in which 80 cylindrical batteries D are arranged in a plane, and FIG. 9B is a side sectional view.

As shown in FIGS. 9A and 9B, a large number (80 pieces) of cylindrical batteries D are completely stored in a box-shaped assembled battery case 33 made of structural members such as aluminum, SUS, and iron. ) Are formed in a matrix. Each cylindrical battery D is connected by a cell terminal connecting member (bus bar) 37 made of a low-resistance conductive member such as copper. FIG.
As shown in (A) and (B), they are fixed to the positive and negative electrode current collector plates 21 and 22 by small screws 37b via washers 37a.

As shown in FIG. 10 (C), if the side of the bus bar 37 which does not come into contact with the cylindrical battery D (the battery pack case side) is coated with silicon carbide (SiC) 38, the insulating effect and the heat can be obtained. Since the conductivity is high, the heat radiation effect is also improved.

If the battery pack is constructed as described above, FIG.
As shown in (1), the distance from the heat generating portion (the center of the unit cell) to the heat radiating portion for cooling is reduced, and the temperature difference between the inside of the unit cell and the outside of the battery case can be reduced. That is, as shown in FIG. 11, if the distance from the heat-generating portion (point A) to the heat-radiating portion (point B) is long, [ΔT = TA-TB] increases rapidly, and the heat-radiating effect is not improved. However, if the vertical height of the cylindrical battery D is reduced as in the present embodiment (FIG. 1).
If X is reduced in 1 (for example, 15 cm or less), the heat radiation effect can be increased.

[Modification] FIGS. 12A and 12B show a case where the bus bar 41 is shaped like glasses. This has the effect of dissipating heat in the center of the battery D, where heat is most likely to accumulate.

(3) Third Embodiment This embodiment is a case where the heat radiation effect is further improved.
As shown in FIG. 13, pleated fins 42 made of aluminum or the like are arranged on both upper and lower surfaces of the battery pack case 33.
By doing so, not only the heat radiation effect is improved, but also the strength of the battery pack with respect to the bending rigidity is improved.

[0026]

As described above, according to the invention described in each of the claims, a positive current collector and a negative current collector having holes are electrically connected to the side end surfaces of the unit cells. The heat generated from the inside of the cell is satisfactorily dissipated, and the heat dissipating fins are formed on the bottom surface and the lid surface of the battery pack housing the cylindrical battery, so that the rigidity of the battery pack box can be increased. .

[Brief description of the drawings]

FIG. 1 is an external perspective view of a cylindrical battery according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the cylindrical battery.

FIG. 3 is a conceptual diagram of a roll constituting the cylindrical battery, in which (A) is a conceptual diagram of winding a belt-like positive electrode current collector and the like;
(B) is a conceptual diagram showing that a positive electrode current collector and a negative electrode current collector are shifted and wound.

FIG. 4 is a conceptual diagram when assembling a unit cell of the cylindrical battery.

FIG. 5 is a diagram illustrating brazing of the unit cells.

FIG. 6 is a view showing another configuration of the roll body of the cylindrical battery, wherein (A) is a plan view and (B) is a side view.

FIG. 7 is a front view and a side view of a first modified example of the positive and negative electrode current collectors in the first embodiment.

FIG. 8A is a front view of a second modified example of the positive and negative electrode current collectors in the first embodiment, FIG. 8B is a front view of a third modified example of the positive and negative electrode current collectors, (C) is an external perspective view of a unit cell using the current collectors of the second and third modifications.

FIG. 9 is a diagram showing an assembled battery of the second embodiment,
(A) is a plan view and (B) is a side sectional view.

FIG. 10A is a perspective view of a joining member between cell terminals,
(B) is a cross-sectional view of the cell-terminal bonding member, and (C) is a cross-sectional view showing a coating of silicon carbide.

FIG. 11 is a diagram illustrating a heat radiation effect of the second embodiment.

FIG. 12 is a perspective view of another example of the cell terminal joining member.

FIG. 13 is a view showing the battery pack of the third embodiment, wherein (A) is a plan view and (B) is a side sectional view.

FIG. 14 is a perspective view of a conventional battery pack for a vehicle.

FIG. 15A is a view showing a mounting position of a conventional battery pack for a vehicle of an automobile, and FIG. 15B is a view for explaining inconvenience of the conventional battery pack for a vehicle.

[Explanation of symbols]

 D cylindrical battery R roll body S unit cell 1 outer case 2 upper lid 3 hollow core 4 lower lid 11 positive electrode current collector 12 positive electrode active material 13 negative electrode current collector 14 negative electrode active material 15 separator 21, 22 current collector plate 21a, 22a Small hole 26 row

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01M 6/02 H01M 6/02 Z

Claims (4)

[Claims] 1. A strip-shaped positive electrode current collector and a negative electrode current collector each holding a positive electrode active material and a negative electrode active material are wound in a roll shape with a predetermined width shifted in a width direction thereof. A power generation unit cell having a hollow hole in the center thereof; a positive electrode current collector having a plurality of holes electrically connected to one side end surface of the wound unit cell; A cylindrical battery comprising: a negative electrode current collector having a plurality of holes electrically connected to the other side end surface of the unit cell. 2. The cylindrical battery according to claim 1, wherein the means for connecting the positive electrode current collector plate and the negative electrode current collector plate to the side end faces of the unit cell is performed by brazing. 3. A hole is provided along the shifted side end surface of at least one of the wound positive electrode current collector and the negative electrode current collector. Item 3. A cylindrical battery according to Item 2. 4. The cylindrical battery according to any one of claims 1 to 3, further comprising a metal battery box arranged in a matrix with its center hole directed vertically. An assembled battery, wherein the assembled battery box is provided with heat dissipating fins on a bottom surface and a lid surface.