JP2000138045A - Set battery and its combination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a set battery having improved energy density by reducing weight. SOLUTION: Four cells having an electrode at both axial ends are arrayed with axial directions kept in parallel, thereby forming a cell row. This cell row is stacked in two stages, and the cells so arranged are electrically connected in series and formed as a set battery body. This set battery body is housed in a covering case 30. Electrodes 15d and 18f at the same side of cells 15 and 18 positioned at both ends of the upper stage are used as terminal electrodes for the connection in series, and the corner part of the covering case 30 having the terminal electrodes is collapsed. The terminal electrodes 15d and 18f are exposed in the collapsed parts 34d and 34e. Also, the projected ends of the terminal electrodes 15d and 18f are positioned behind the edge 34f of the covering case 30 between both collapsed parts 34d and 34e in a battery axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery and a connected body thereof, and more particularly to a technique for improving a weight energy density.

[0002]

2. Description of the Related Art An assembled battery is a device in which a plurality of cells are connected in series, and is therefore used for equipment requiring high power. FIG. 7 shows a schematic configuration of an example of a conventional assembled battery. As shown in the figure, the assembled battery is composed of eight unit cells 1 formed by stacking four unit cells side by side and stacking them in two stages.
01 to 108, and these cells are connected in series by seven connectors 109 to 115. Module terminals 116 and 117 are connected to the terminal electrodes 101a and 104a of the unit cells connected in series,
The whole is stored in case 118.

A large capacity battery of several tens of kilograms is manufactured for each of these types of battery packs. In recent years, electric vehicle vehicles, which have attracted attention particularly in view of environmental problems and energy problems, have been manufactured. About 10 to 20 are connected.

[0004]

SUMMARY OF THE INVENTION In an electric vehicle,
Since the mileage that can be performed by one charge varies depending on the weight of the entire vehicle, a slight increase in the weight of each battery pack cannot be ignored in the above case. That is, it is desired to improve the weight energy density of the assembled battery. The present invention has been made in view of the above problems, and has as its object to provide an assembled battery with reduced weight and improved weight energy density, and a connected body of the assembled battery.

[0005]

In order to achieve the above-mentioned object, a battery assembly according to the present invention is configured such that cells having electrodes at both ends in the axial direction are arranged in parallel in the axial direction to form a battery row. In a battery pack in which a plurality of the battery rows are stacked and the entire stack is housed in the covering case, and the housed cells are electrically connected in series, the same side of the cells located at both ends of the same stage Is a terminal electrode of the series connection, a corner portion of the covering case where the terminal electrode exists is depressed, and the terminal electrode is exposed in the depressed portion.

Further, in the unit cell, a power generating element is housed in a space surrounded by a cylindrical outer can and a sealing lid for sealing both end openings, and electrodes are provided so as to protrude from an end face of the sealing lid. Wherein the projecting end of the terminal electrode is
It is characterized in that it is receded in the battery axis direction from the position of the end face of the covering case existing between the two depressions. In addition, the assembled battery assembly according to the present invention includes a plurality of the assembled batteries, wherein all the terminal electrodes are arranged substantially on a straight line, and the covering case side faces of the adjacent assembled batteries are arranged to be in contact with each other. The battery is characterized in that the terminal electrodes in the immediate vicinity of the battery are connected by a conductive connector.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a battery pack according to the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of a unit cell constituting the assembled battery main body, FIG. 2 is an external perspective view of the assembled battery main body, and FIG. As shown in FIG. 2, the unit battery shown in FIG. 1 has four unit cells arranged in a row and stacked in two stages. As shown in FIG.
It is configured to be stored in.

The unit cell is a lithium secondary battery. As shown in FIG. 1, a sheet is placed in a space surrounded by a cylindrical outer can 11a and sealing lids 11b and 11c for sealing openings at both ends. A separator is sandwiched between a sheet-like positive electrode and a sheet-like negative electrode, and a power generating element composed of a spiral element wound spirally and an electrolyte is housed therein. A positive terminal 11d and a safety valve 11e are attached to the sealing lid 11b, and a male screw is formed on the positive terminal 11d.

A negative terminal 11f formed with a male screw and a safety valve (11g) are attached to the sealing lid 11c, and have the same appearance as the positive terminal. Reference numeral 11h denotes an electrode terminal mounting nut for mounting the positive electrode terminal 11d to the sealing lid 11b, and the negative electrode terminal 11f is similarly mounted to the sealing lid 11c with an electrode terminal mounting nut.

The cell 10 has an outer can 11a having an outer diameter φD of 64 mm and a length L1 between end faces of the sealing lids 11b and 11c of 294 mm. The assembled battery body is composed of the same eight single cells as described above. As shown in FIG.
Four single cells 1 arranged with their axis directions parallel
It has a two-stage configuration in which four unit cells 15, 16, 17, 18 similarly arranged on 1, 12, 13, 14 are stacked. The cells adjacent to each other are arranged so that the cells having different polarities are on the same side, and the cells adjacent in the vertical direction are also arranged such that the cells having different polarities are on the same side. With such an arrangement, series connection is possible by connecting the electrode terminals of adjacent unit cells one after another.

In this connection, a connecting member 1 as shown in FIG.
9 is used. As shown in this figure, the connection body 19 is configured by inserting and fixing copper caps 19b at both ends of a nickel stranded wire 19a.
Is provided with an electrode terminal insertion hole 19c. Returning to FIG. 2, the connection body 19 is configured such that the positive electrode terminal of one cell to be connected to one electrode terminal insertion hole 19c is inserted, and the negative electrode terminal of the other cell is inserted into the other electrode terminal insertion hole 19c. In this state, it is fixed and attached with the connector attaching nut 20. That is, the cap of the connector 19 is sandwiched between the electrode terminal mounting nut and the connector mounting nut.

The connecting bodies 19 are mounted such that the cells 15 and 18 located at both ends of the upper stage of the upper and lower stages are the terminal cells of the series connection. Therefore, in this case, the positive electrode terminal 15d of the unit cell 15 and the negative electrode terminal 18d of the unit cell 18 serve as a terminal electrode for series connection. Hereinafter, the positive electrode terminal 15d and the negative electrode terminal 18f may be particularly referred to as termination electrode terminals.

FIG. 5 is an exploded perspective view of a cover case 30 for housing the assembled battery body configured as described above. As shown in the figure, the covering case 30 includes a pedestal 31 and a top plate 3.
2. It is composed of a back plate 33 and a front plate 34, and each material is non-conductive polycarbonate. A plurality of convex portions (a number of substantially rectangular portions illustrated in FIG. 3) are provided on the surface that appears in the front in the assembled state, but are omitted in the drawing.

The pedestal 31 mainly includes the lower cells 11 to 1
4 (FIG. 2), and the ribs 31a, 31
b, 31c are provided. These ribs 31a, 3
Each of the cells 11 to 14 is supported at three places (both ends and a center part) in the longitudinal direction by 1b and 31c. Each rib 31a-3
The portion 1c that comes into contact with the unit cell conforms to the outer shape of the unit cell, and has a circular cross section substantially equal to the outer diameter of the unit cell, so that the mounted unit cell is stored without rattling. The length L2 of the pedestal 31 shown in the drawing is substantially equal to the length L1 of the cell, and each cell has an end face of the sealing lid at both ends and an end face 31d of the pedestal 31 shown in FIG.
31e are placed so as to be substantially aligned (so-called flush).

The top plate 32 is mainly composed of the upper cells 15-1.
8 (FIG. 2).
Similar ribs 32a to 32c are provided at positions corresponding to a to 31c.
c, whereby each of the upper cells 1
5 to 18 are stored without rattling. The back plate 33 is
This cover covers the connection portion of the battery assembly main body on the back side of the paper surface shown in FIG. 2, and a portion (electrode terminal, connection body, etc.) protruding from the end surface of the sealing lid of the unit cell is formed on the back plate 33. It is stored in the recess 33a.

The front plate 34 is for covering the connecting portion of the battery assembly main body on the near side in FIG. 2 and for exposing the terminal electrode terminals 15d and 18f to the outside of the covering case. Portions (electrode terminals, connectors, and the like) protruding from the end surfaces of the sealing lids of the cells 11 to 14, 16, and 17 (see FIG. 2) are housed in the recesses 34a having a mountain-shaped cross section of the front plate 34. You.

On the other hand, terminal electrode terminals 15d, 15d, through terminal electrode terminal insertion holes 34b, 34c provided in front plate 34, respectively.
18f is exposed outside the covering case. That is, in the assembled state of the covering case, when viewed from the whole covering case, the corner portion of the covering case where the terminal electrode terminal exists is depressed, and the terminal electrode terminal is exposed at the depressed portions 34d and 34e. is there. In the state where the front plate 34 is mounted on the pedestal 31, the thickness t1 of the portion of the front plate 34 shown in the drawing is such that the end face of the electrode terminal mounting nut of the cell slightly projects from the terminal electrode terminal insertion hole. The length t2 of the entire front plate 34 is set such that the protruding end of the terminal electrode terminal is retracted from the end surface position of the front plate 34.

In the covering case 30 having the above structure, first, the assembled battery main body shown in FIG. In this case, after the cells 11 to 18 are arranged on the pedestal 31, the connection by the connecting bodies 19 may be performed. Next, the top plate 32 is placed on the pedestal 31 and fixed with six screws. With the top plate attached to the pedestal 31, the back plate 33 and the front plate 34 are fixed with six screws each.

When assembled as described above, the assembled battery has a height H = 135 mm and a width W = W, as shown in FIG.
The dimensions are 264 mm and depth L3 = 352 mm. As shown in the figure, since the protruding ends of the terminal electrode terminals 15d and 18f are retracted from the end surface 34f of the covering case 30, an unexpected short circuit between the terminal electrode terminals 15d and 18f can be prevented. . That is, the termination electrode terminals 15d and 1d
By making a part of the covering case exist between 8f, it becomes impossible to connect both terminals linearly with a conductor,
For example, no matter how the battery pack is placed on a flat metal plate or the like in a careless manner, a short circuit does not occur.

Further, since the terminal terminals 15d and 18f are not provided with a module terminal as in the conventional battery pack shown in FIG. 7 (because they are in an exposed state), the weight is reduced accordingly. That is, the weight is reduced by directly using the electrode terminal of the unit cell as a terminal for extracting current from the assembled battery. Here, a comparison of the weight energy density (Wh / kg) between the conventional battery pack shown in FIG. 7 (hereinafter referred to as “comparative battery pack”) and the battery pack according to the embodiment shown in FIG. went. The unit cells used for the comparative battery pack are the same as those used for the battery pack according to the embodiment. The weight of the battery pack according to the embodiment is 21.0 kg, and the weight of the comparative battery pack is 21.kg.
It was 5 kg.

The capacity of the assembled battery is measured by constant current charging / discharging. At the time of charging, a constant current of 10 A is supplied until the voltage becomes 33.6 V (each cell is 4.2 V). , 8.
The battery was discharged at 8 A until the voltage reached 21.6 V (each cell was 2.7 V). As a result, the assembled battery according to the embodiment had an average voltage of 28.8 V and a discharge capacity of 80 Ah. That is, the discharge power is 2300 Wh, and the weight energy density obtained by dividing this by the weight of the battery pack is 11
It became 0 Wh / kg.

On the other hand, the discharge capacity (discharge power) of the comparative battery pack
Was the same value as the assembled battery according to the embodiment, but 107 Wh / kg was obtained as the weight energy density calculated from this and the weight of the assembled battery. Table 1 summarizes the above results.

[0023]

[Table 1]

In other words, the battery pack according to the embodiment has a weight energy density improved by 3 Wh / kg compared to the comparative battery pack. FIG. 6 shows a connected body of assembled batteries in which a plurality of the assembled batteries (two in this example) are connected. As shown in this figure, the connected body of the battery pack is composed of a battery pack 1 and a battery pack 2
Are the termination electrode terminals 15d, 15f, 150d, 150f
Are arranged almost in a straight line, and the side surfaces of the casings of the assembled batteries 1 and 2 are in contact with each other. The terminal electrode terminals 15f and 150d closest to both the assembled batteries are connected in the same type as shown in FIG. It is configured to be connected by a body 190.

Since the corner portion of the covering case where the terminal electrode terminal of each battery pack is present is depressed, the connection by the connecting member can be easily performed, and the terminals can be connected with the shortest distance. The connecting body can be shortened, and the entire weight of the connecting body can be reduced. In addition, in the assembled battery main body, since the terminal electrodes on the same side of the unit cells located at both ends of the same stage are used as the terminal electrodes, it is possible to avoid a situation in which terminals of the same polarity are erroneously connected. Play. This effect can be obtained as long as the unit cells arranged in parallel are stacked in odd-numbered stages, and the middle stage of the stages is not selected as the stage for extracting the terminal electrode terminal.

In the above embodiment, four cells are stacked in two layers, but the number of cells and the number of cells per layer are not limited to this. Further, in the above embodiment, the lithium secondary battery is used as the unit cell.
It goes without saying that the battery used for the unit cell is not limited to this, and another type of secondary battery or primary battery may be used.

Further, in the above embodiment, the connected body is constituted by two sets of assembled batteries, but the number of assembled batteries constituting the joined body is not limited to this, and three or more sets may be used. In the above embodiment, the covering case is divided into four parts, but the number of divisions is not limited to this. For example, the pedestal and the rib portion of the top plate may be formed separately and joined with an adhesive or the like.

[0028]

As described above, according to the battery pack of the present invention, the terminal electrode is exposed, and power is directly taken out from the terminal electrode. The weight is reduced as compared with the case where the terminal for taking out is attached, and the energy density is improved.

Further, since the corner portions of the covering case where the terminal electrodes are present are depressed, when the assembled batteries are connected in series, the connection between the terminal electrodes by the connecting member is facilitated, and both assembled batteries are connected. By arranging such that the side surfaces of the covering case are in contact with each other, the connection distance by the connection body is minimized, and the connection body can be shortened, so that weight can be reduced. Furthermore, since the protruding end of the terminal electrode is retracted in the battery axis direction from the end surface position of the covering case existing between the recessed portions of the covering case where the terminal electrode is exposed, the conductive between the two terminal electrodes is provided. The connection cannot be made linearly by the body, and an unexpected short circuit can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a cell constituting a battery pack according to an embodiment.

FIG. 2 is a perspective view showing a schematic configuration of a main body of the battery pack according to the embodiment.

FIG. 3 is an external perspective view showing a schematic configuration of the battery pack according to the embodiment.

FIG. 4 is a perspective view showing a schematic configuration of a connecting body used for the battery pack main body.

FIG. 5 is an exploded perspective view showing a schematic configuration of a cover case of the battery pack according to the embodiment.

FIG. 6 is an external perspective view illustrating a schematic configuration of a connected body of the assembled battery according to the embodiment.

FIG. 7 is a perspective view showing a schematic configuration of a conventional battery pack.

[Explanation of symbols]

11, 12, 13, 14, 15, 16, 17, 18 Single cell 15d, 18f, 150d, 180f Terminal electrode terminal 19 Connection body 30 Covering case 34d, 34e Depressed part 190 Connection body

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Atsushi Yanai 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Atsuhiro Funabashi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Toshiyuki Noma 2-5-5-Keihanhondori, Moriguchi-shi, Osaka Pref. Sanyo Electric Co., Ltd. (72) Inventor Ikuo Yonezu Keihan-hondori, Moriguchi-shi, Osaka 2-5-5 Sanyo Electric Co., Ltd. (72) Inventor Koji Nishio 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H020 AA01 AS06 AS11 CC15 CC17 CC19 DD02 DD08 DD12 5H022 AA09 CC02 CC09 CC12 CC25 KK04

Claims (3)

[Claims] 1. A single cell having electrodes at both ends in the axial direction is arranged in parallel in the axial direction to form a battery row, a plurality of the battery rows are stacked, and the entire stack is housed in a covering case. In a battery pack in which the stored cells are electrically connected in series, electrodes on the same side of the cells located at both ends of the same stage are
An assembled battery as the terminal electrode of the series connection, wherein a corner portion of the covering case where the terminal electrode exists is depressed, and the terminal electrode is exposed in the depressed portion. 2. The power generation element of the unit cell is housed in a space surrounded by a cylindrical outer can and a sealing lid that seals both end openings, and an electrode is provided so as to protrude from an end face of the sealing lid. 2. The assembled battery according to claim 1, wherein the protruding end of the terminal electrode is retracted in the battery axial direction from an end surface position of the covering case existing between the two recesses. 3. . 3. A plurality of the assembled batteries according to claim 1 or 2, wherein all of the terminal electrodes are arranged substantially in a straight line, and the side faces of the covering case of the adjacent assembled batteries are arranged so as to be in contact with each other. Wherein the terminal electrodes immediately adjacent to each other are connected by a conductive connector.