JPH06338304A - Cell and battery structure - Google Patents

Abstract

PURPOSE:To improve the energy volume density and the weight density, and to lighten and downsize a device by forming one side surface of a cell case, which is formed in parallel with an electrode surface of a layered electrode, into a flexible thin plate. CONSTITUTION:A negative electrode 21b and a positive electrode 21a are arranged alternately so that each lead part thereof is overlapped with each other, and a polyethylene film 21c is interposed between them for lamination, and the periphery thereof is wound with a viscous tape 11 for fixation to form a layered electrode 10. A positive and a negative lead parts 13, 14 are welded to a positive and a negative electrode terminals 5, 6 inside of a barrel part 2. Thereafter, a film 3 made of aluminium foil, which is laminated with polyethylene at a predetermined thickness, is fixed to both side surfaces of the barrel part 2 by the heat seal, and the electrolyte is filled from an electrolyte filing port 8 provided in the upper part of the case 4. Since the side surfaces of the case are thereby formed flexible, a cell is lightened. Plural cells are arranged inside of a battery case and pressurized by a pressurizing spring to form a battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit cell which is light in weight, has a high energy volume density and a high weight density, and has excellent cycle characteristics, and an assembled battery structure incorporating a plurality of these unit cells.

[0002]

2. Description of the Related Art In recent years, due to problems such as energy saving and environmental pollution, there has been a strong demand for development of batteries for power storage and electric vehicles.
High energy capacity and high energy density are required at high voltage (tens to hundreds of volts). On the other hand, there are two types of cells used for these, a spiral type structure formed by winding a long electrode and a flat rectangular structure formed by laminating flat electrodes. The unit cell is generally known. The spiral-type cell has a relatively large load area because it has a large electrode area, but it has a bad space factor because it has a cylindrical shape. When doing so, there is a drawback that the volume energy density is lowered.
Further, there is a problem that the heat storage during charging / discharging causes a large amount of heat storage, resulting in large deterioration of battery characteristics. On the other hand, the rectangular cell has a good space factor,
The heat storage during charging / discharging is also small, and when used in an electric vehicle or the like, it is suitable as an assembled battery in which a plurality of unit cells are connected, and is currently being used experimentally.

[0003]

However, in the above-mentioned conventional flat type cell, since a plurality of plate electrodes are simply inserted and laminated in the rigid case,
The adhesion between the flat plate electrodes is poor, sufficient capacity cannot be obtained, and at the same time, there is a problem that the cycle characteristics are remarkably deteriorated, and the conventional type of single cell is insufficient.
By the way, in order to improve the adhesion between the electrodes, as shown in FIG. 23, it is conceivable to incorporate an electrode pressing spring 60 for pressing the laminated electrode 10 of the unit cell 61 in the unit cell case 66. When the electrode pressing spring 60 is built in the battery 61, the following problems occur. That is,
1) The weight of the unit cell itself increases, and the energy weight density decreases. 2) A metal case having rigidity that can withstand the reaction force of the pressurizing spring in the unit cell is required, and the volume and weight of the unit cell are further increased in combination with the built-in spring, and the energy density of the unit cell is increased. Has the drawback that it decreases. 3) When a plurality of single cells are combined and used as an assembled battery, there is a problem that the volume and weight occupying the whole are accumulated, and the energy density of the assembled battery is significantly lowered.

Further, 4) When a single battery is charged and discharged, it generates heat, so that the body portion of the single battery case expands and the electrodes are laminated like a lithium battery, for example, a prismatic battery. In the case of a single battery, expansion of the body part may weaken the pressure applied to the laminated electrode body and cause it to stop functioning as a battery. Therefore, conventionally, in order to maintain the pressure applied to the laminated electrode body, it is necessary to increase the rigidity of the case structure having a rigidity of a predetermined value or more, that is, the rigidity of the body portion of the case and the side plates attached to both surfaces of the body portion. If the body part and the side plates are wound and assembled by assembling without winding, the body part of the case will be too thick as a result. In particular, when the side plate is wide and parallel to the laminated electrode body, there is a problem that the case body part must be thickened in order to ensure rigidity regardless of heat generation. Therefore, an object of the present invention is to provide a unit cell in which the weight of the case is reduced, the energy volume density and the weight density are increased, and the unit cell case is rolled up and sealed, and an assembled battery structure using the unit cell. I am trying.

[0005]

In order to achieve the above object, the unit cell according to the present invention is a flat unit cell in which a laminated electrode body in which flat plate-shaped or sheet-shaped electrodes are stacked is housed in a unit cell case. The battery is characterized in that at least one of the side surfaces of the unit cell case parallel to the electrode surface of the laminated electrode body is formed as a flexible thin plate.

Further, the unit cell according to the present invention is characterized in that the unit cell case has a side surface parallel to the stacking direction of the stacked electrode body,
At least two or more battery terminals are provided. Further, the unit cell according to the present invention is characterized in that the unit cell case is composed of a plurality of members, and peripheral portions of the plurality of members are wound around each other and assembled and sealed. Further, in the unit cell according to the present invention, the unit cell case is composed of a tubular body portion and both side plates sealing both side openings of the body portion, and peripheral portions of the body portion and each side plate. It is characterized in that they are wound around each other and assembled. Further, in the unit cell according to the present invention, the unit cell case part assembled by winding the peripheral portions of the body part and the side plates into each other is projected in a direction orthogonal to the stacking direction of the stacked electrode body. Characterize. Further, in the unit cell according to the present invention, the unit cell case is composed of a case portion in which a tubular body portion and one side plate are integrated, and a side plate which seals an opening of the case portion. It is characterized in that the peripheral portions of the portion and the side plate are wound around each other and assembled.

Further, the assembled battery structure according to the present invention is provided on both side surfaces of a single battery case which accommodates a laminated electrode body in which flat plate-shaped or sheet-shaped electrodes are laminated and which faces the electrode surface of the laminated electrode body. Among them, in a battery pack structure in which at least one side surface is formed into a flexible thin plate and a plurality of battery cells are arranged and housed in a battery pack case with the electrode surfaces of the battery cells in parallel, It is characterized in that a pressurizing spring for applying pressure from one side of the battery case toward the arrangement direction of the plurality of unit cells is provided.

[0008]

Therefore, according to the present invention, since the side surface of the unit cell case is formed flexibly, it is not necessary to form the unit cell case with a rigid member, and the unit cell itself can be reduced in weight and size. In addition, it is not necessary to increase the plate thickness of the case even if the unit cell case is rolled up and assembled.
It is not affected by the expansion of the unit cell case due to the heat generated during discharge, and a rigid case structure is not required to hold the pressure applied to the laminated electrode body, which facilitates the production of unit cells. Become. Further, since the pressurizing spring is provided in the battery pack case, the pressure-bonding property of the laminated electrodes in the plurality of cells arranged in the battery pack case is improved, a sufficient capacity is obtained, and the cycle of the battery pack structure is improved. It is possible to obtain a single cell and an assembled battery structure having improved characteristics and high energy volume density and weight density.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the unit cell according to the present invention will be described below with reference to the drawings. FIG. 1 shows a unit cell 1 according to this embodiment.
FIG. As shown in FIG. 1, the unit cell 1 of the present embodiment is composed of a unit cell case 4 including a body portion 2 and a film 3, and a laminated electrode body 10 housed in the case 4. Both sides are flexible. The body portion 2 is made of polyethylene in a substantially square tubular shape, and a positive electrode terminal 5 and a negative electrode terminal 6 are fixedly mounted on the upper surface of the body portion 2 to secure a safety valve 7
Also, an electrolyte injection port 8 is provided. The film 3 is formed of a polyethylene-laminated aluminum foil having a thickness of 100 μm, and is fixed to both side surfaces of the body portion 2 by heat sealing at points marked with “X” in FIG.
The openings on both sides of the body 2 are sealed.

The laminated electrode body 10 has a large number of negative electrodes 2.
1b and the positive electrode 21a, and the polyethylene film 21c interposed between these electrodes. That is, in the present embodiment, the negative electrode 21b is
90 parts by weight of carbon having an average particle size of 20 μm obtained by firing in an inert gas stream and pulverization was used, and 10 parts by weight of vinylidene fluoride resin was used as a binder, and these were dispersed in N-methylpyrrolidone. The resulting slurry is applied to both sides of a copper foil current collector having a thickness of 10 μm to give a thickness of 180 μm.
An electrode original plate having a thickness of μm is produced, and an applied part of the electrode original plate is cut into a size of 82 mm × 284 mm while leaving an uncoated part to be the lead portion 14 of the negative electrode in a part of the electrode original plate.

The positive electrode 21a has an average particle size of 15 μm.
91 parts by weight of LiCoO ₂ powder, 6 parts by weight of graphite as a conductive material, 3 parts by weight of vinylidene fluoride resin as a binder, and a slurry obtained by dispersing these in N-methylpyrrolidone was collected as a copper foil. An electrode original plate having a thickness of 150 μm is produced by applying it to both surfaces of the electric body, and the applied part of the electrode original plate is 77 mm × 279 mm, leaving an uncoated part to be the lead portion 13 of the positive electrode in a part of this electrode original plate It is formed by cutting to the size of. The polyethylene film 21c has a thickness of 38 μm and a size of 87 mm × 289 mm, and has a large number of minute holes. And 43 pieces of the negative electrode 21b and the positive electrode 21a
42 sheets and the positive and negative lead portions are overlapped and alternately arranged, and the polyethylene film 21c is interposed therebetween to be laminated, and the adhesive tape 11 is wound around the outer periphery of both the electrodes 21.
The a and 21b and the film 21c are fixed to form the laminated electrode body 10. Furthermore, the positive electrode lead portion 13 and the negative electrode lead portion 14 of the laminated electrode body 10 are welded inside the body portion 2 to the positive electrode terminal 5 and the negative electrode terminal 6 fixedly mounted on the upper surface of the body portion 2. After connection, the films 3 are fixed to both side surfaces of the body portion 2 by heat sealing, and the electrolytic solution is injected from the electrolytic solution injection port 8 on the upper part of the case 4. The electrolytic solution is formed by dissolving LiPF6 at a ratio of 1 mol / l in a mixed solvent of propylene carbonate and diethyl carbonate. And
After the electrolytic injection, the injection port 8 is plugged, whereby the unit cell 1 having a design capacity of 34 Ah is configured.

Therefore, in this embodiment, since the side surface of the unit cell case 4 is made of the aluminum foil film 3, the side surface of the case becomes flexible and the weight of the unit cell can be reduced. Further, in this embodiment,
Since the positive electrode terminal 5 and the negative electrode terminal 6 are fixed to the upper surface of the body portion 2 of the unit cell case 4 parallel to the stacking direction of the stacked electrode body 10, the positive electrode lead portion 1 of the stacked electrode body 10 is fixed.
3 and the negative electrode lead portion 14 and the lead wire connecting the positive electrode terminal 5 and the negative electrode terminal 6 of the unit cell case 4 can be routed around the positive electrode 21a and the negative electrode 21b, and the laminated electrode Even when the laminated electrode body 10 is used while being pressed in the laminating direction in order to improve the adhesion between the positive electrode 21a and the negative electrode 21b of the body 10, the mechanism is simplified and the lead wires can be easily connected. .

Next, a second embodiment of the unit cell according to the present invention will be described. The description of the same parts as those in the first embodiment will be omitted. FIG. 2 shows an exploded perspective view of the unit cell 1 of this embodiment. In this embodiment, the laminated electrode body 10 and the electrolytic solution are configured in the same manner as in the above embodiments. The laminated electrode body 1
The unit cell case 4 in which 0 is stored is composed of a lower case portion 15 and an upper lid 18. The lower case portion 15 is a body portion 16 formed in a U shape with a thickness of 1 mm of stainless steel.
And both side plates 1 fixed to both side surfaces of the body portion 16 by laser welding and formed on a stainless steel foil having a thickness of 50 μm.
7 and 7. The upper lid 18 has a thickness of 1.5.
As in the first embodiment, the positive electrode terminal 5 and the negative electrode terminal 6 are fixedly provided, and the safety valve 7 and the electrolytic solution inlet 8A are provided on the upper surface. Further, the laminated electrode body 10 inserted into the lower case portion 15 is
An insulating film 19 is interposed between the lower case portion 15 and the lower case portion 15. In FIG. 2, 11 indicates an adhesive tape.

Then, the positive electrode lead portion 13 and the negative electrode lead portion 14 of the laminated electrode body 10 are connected to the lower portions of the positive electrode terminal 5 and the negative electrode terminal 6 fixed to the upper lid 18 by welding, and thereafter, The laminated electrode body 10 is inserted into the lower case portion 15 with the insulating film 19 interposed therebetween, and the upper lid 1
8 is laser-welded to the lower case portion 15, and the electrolyte injection port 8
The unit cell 1 is constructed by injecting the electrolytic solution from the above and closing the plug 8A. Also in this embodiment, the design capacity is 34 Ah. Therefore, also in this embodiment, since the side plate of the unit cell case is made of thin stainless steel foil, the side surface of the case is flexible and the unit cell can be reduced in weight. Further, since the positive electrode terminal 5 and the negative electrode terminal 6 are fixed to the upper lid 18 of the unit cell case 4 parallel to the stacking direction of the stacked electrode body 10, avoid the positive electrode 21a and the negative electrode 21b. The lead wire can be routed, and the laminated electrode body 10
The mechanism is simplified and the lead wires can be easily connected even when pressure is applied in the stacking direction.

Further, a third embodiment of the unit cell according to the present invention will be described. FIG. 3 shows an exploded perspective view of the unit cell 1 of this embodiment. In this embodiment, the unit cell case 4 is formed by molding the laminate film 20 into a bag shape by heat sealing. That is, the single battery case 4
Is formed by inserting the above-mentioned laminated electrode body 10 into a laminate film 20 formed into a tubular shape from a polyethylene laminate aluminum foil having a thickness of 100 μm and sealing both ends by heat sealing. The whole is made flexible.

The electrode terminals 5 and 6 are fixed to the laminate film 20 by heat sealing, and an electrolyte injection port 8 is provided at a part of the laminate film 20 by heat sealing. Further, the electrolyte injection port 8 has a similar film stopper 8
A is fixed by heat sealing. Then, each lead portion 1 of the laminated electrode body 10 is attached to the positive electrode terminal 5 and the negative electrode terminal 6 fixed to the laminate film 20.
Laminated film 20 by connecting 3 and 14 by welding
Is molded into a bag shape by heat sealing, the electrolytic solution is injected from the electrolytic solution injection port 8, and a film stopper 8A is fixed to the electrolytic solution injection port 8 by heat sealing to seal the electrolytic solution injection port 8. The unit cell 1 is configured. Also in this embodiment, the design capacity is 34 Ah.

Therefore, in this embodiment, the entire unit cell case is flexible, and the weight of the entire unit cell is reduced. In addition, the positive electrode terminal 5 and the negative electrode terminal 6
Is a unit cell case 4 parallel to the stacking direction of the stacked electrode body 10.
Since it is fixed to the location by heat sealing, the lead wire can be routed avoiding the positive electrode and the negative electrode, and the mechanism is simple even when the laminated electrode body 10 is used while being pressed in the laminating direction. The lead wires can be easily connected.

Next, a first embodiment of the assembled battery structure according to the present invention will be described. FIG. 4 shows an exploded perspective view of the assembled battery structure 40 of this embodiment. The assembled battery structure 40 of the present embodiment is configured by arranging a plurality of the unit cells 1 shown in FIG. 1 and inserting them in the assembled battery case 41. That is, the battery pack case 41 is composed of two side plates 42, a frame 43, a pipe 44, etc.
3, the pipe 44 is connected by the bolt 45. In the present embodiment, the assembled battery case 41 is formed in a size such that the seven unit cells 1 can be arranged with their side surfaces adjacent to each other. A pressing leaf spring 46 is attached to the inner surface of both side plates 42 of the battery pack case 41. These pressing leaf springs 46 have a thickness of 0.5 mm and an original dimension of 87 mm.
It is formed by bending a SUS304-CSP having a size of × 289 mm to a curvature of R = 75.

When all the unit cells 1 are installed in the assembled battery case 41, the compression leaf springs 46 of the side plates 42 are distorted to the side of each of the seven unit cells 1 installed in the assembled battery case 41. A pressing force is applied from the direction of the parts, the laminated electrode body 10 in each unit cell 1 is pressed in the laminating direction, and the electrodes of the laminated electrode body 10 are pressure bonded. When the pressing force of one leaf spring 46 at this time was measured, it was about 50 Kg, and the total load of about 100 Kg was applied between the electrodes in each cell 1 by the leaf springs 46 on both sides. To work. Therefore, when a plurality of unit cells 1 are used as an assembled battery, the adhesion of the laminated electrodes in each unit cell 1 is enhanced, a sufficient capacity is obtained, and the cycle characteristics can be improved. The assembled battery case 41 of this embodiment may include a plurality of unit cells 1 shown in FIG. 2 to form an assembled battery structure.

Furthermore, the second of the assembled battery structure according to the present invention.
Examples will be described. FIG. 5 shows a perspective view of the assembled battery structure 40 of this embodiment. In this embodiment, the bag-shaped unit cell 1 shown in FIG. 3 is used. Therefore, the upper lid 49 to which the electrode terminals 47 and 48 are attached is used, and the electrode terminals 47 and 48 of the upper lid 49 are connected to the electrode terminals 5 and 6 of each unit cell 1 to form the assembled battery unit cell 1. Seven such unit cells 1 for assembled batteries are adjacently inserted into the assembled battery case 41 with the upper lid 49 as a guide. Further, as the assembled battery case 41, as in the above embodiment,
A pressing leaf spring 46 is provided in one of the side plates 42 on both sides, and each unit cell 1 installed in the assembled battery case 41 is
The structure is such that a sufficient load can be applied to the laminated electrode. Therefore, similarly to the above, when using a plurality of unit cells 1 as an assembled battery, the adhesion of the laminated electrodes in each unit cell 1 is enhanced, a sufficient capacity is obtained, and the cycle characteristics can be improved.

The inventor of the present invention has found that the various unit cells 1 of the above embodiment are
23 and the assembled battery structure 40, and the pressing spring 6 shown in FIG.
A test was performed comparing the unit cell 61 containing 0 and the assembled battery structure using the unit cell 61. The results will be described below. In the unit cell 61 with a built-in pressure spring for comparison, the laminated electrode body 10 is formed in the same manner as described above, and the laminated electrode body 10 has a thickness of 2.5 mm and a thickness of 87.
A pressurizing leaf spring 60 similar to that described above is arranged via a stainless steel intermediate presser plate 62 of 5 mm × 289 mm, and a thickness is provided on the outer side of the pressurizing leaf spring 60 and the other surface of the laminated electrode body 10. A pressing plate 63 having a length of 2.5 mm is provided, and a stainless steel belt 64 having a thickness of 0.1 mm is wound around the outer circumference of these while pressurizing by a hydraulic pump and resistance welding is performed to fix the leaf spring 60. .

Then, each lead portion 1 of the laminated electrode body 10
3, 14 are connected to the electrode terminals 5, 6 fixed to the upper lid 65 by welding, respectively, and the plate thickness is 1.2 mm and the outer diameter is 24 mm.
Insert it in the lower case 66 made of stainless steel of × 105 mm,
The upper lid 65 was fixed to the lower case portion 66 by laser welding, and the electrolytic solution was injected in the same manner as described above to form the unit cell 61 in which the pressing leaf spring 60 was arranged in the lower case portion 66 having rigidity. Further, as the assembled battery structure using the unit cells 61, the seven pressure-built-in spring type unit cells 61 formed as described above are adjacent to each other, and the side plate 4 of the assembled battery case 41 is provided.
2 is arranged in the battery pack case 41 in which the pressing leaf spring 46 is not provided to form a battery pack structure. Then, the unit cell 1 of each of the above-described examples, the unit cell 61 of the comparative example with a built-in spring for pressurization, the assembled battery structure 40 of each example above, and the unit cell of the comparative example with a built-in spring for pressurization. The assembled battery structure using 61 was tested for each characteristic. As a result, the results shown in [Table 1] were obtained.

[0023]

[Table 1]

A charging / discharging characteristic test was conducted on the unit cells 1 and 61 of the above-mentioned examples and comparative examples under the following conditions. Charging condition: 23 ° C, constant current 1C × 3H, 4.2V constant voltage charging Discharging condition: 23 ° C, 1C constant current discharging As a result, both charging current and discharging current were 34A in the case of the above example, and comparison In the case of the example, it is 20A. In addition, in the cycle characteristic test of [Table 1], charge and discharge were repeated 100 times under the above charge and discharge conditions to measure the discharge capacity retention rate. According to the above test results, [Table 1]
As can be seen from the above, the cycle characteristics are deteriorated when only the unit cell 1 is used, but the cycle characteristics are not deteriorated as the assembled battery structure 41, and the unit cell 1 and the assembled battery structure having high energy volume density and high weight density are obtained. 40 can be obtained.

Further, a fourth embodiment of the unit cell according to the present invention will be described. In this embodiment, the square lithium 2
The case of the next battery will be described as an example. FIG. 6 is an exploded perspective view of the unit cell 1 of this embodiment before assembly, and FIG. 7 is a unit cell 1.
FIG. 8 is a cross-sectional view showing a winding structure. As shown in FIGS. 6 and 7, the unit cell 1 according to the present embodiment includes a unit cell case 4 including a tubular body portion 2 and side plates 3 fixed to both surfaces of the body portion 2, and the unit cell case 4. It is composed of the laminated electrode body 10 housed in the case 4. The side plate 3 of the unit cell case 4 has a thin plate thickness and has a flexible structure. The body portion 2 and the side plate 3 are formed of an insulating metal such as aluminum, and the laminated electrode body 10 is for a lithium battery having positive and negative electrode lead portions 13 and 14 formed by laminating a plurality of positive electrode electrodes and negative electrode electrodes. It is configured. Then, the laminated electrode body 10
The positive and negative electrode lead parts 13 and 14 of the above are connected to the positive and negative electrode terminals 5 and 6 fixedly mounted on the upper surface of the body part 2 by welding inside the body part 2, and then both side plates 3 are connected to the body part 2. It has a structure in which it is assembled by winding, is sealed, and is filled with an electrolytic solution.

As the tightening structure of the body portion 2 and the side plate 3, various kinds of tightening structures can be considered as shown in FIGS. That is, as shown in FIG. 8 and FIG. 9, the peripheral portions of both the body portion 2 and the side plates 3 are wound so as to protrude along the laminating direction of the laminated electrode body 10 and sealed,
As shown in FIGS. 10 to 12, both peripheral edge portions are wound and sealed so as to project in a direction orthogonal to the stacking direction of the stacked electrode body 10. In the case of the winding tightening projecting in the direction orthogonal to the stacking direction of the stacked electrode body 10 as shown in FIGS. 10 to 12, when the assembled battery structure 40 is configured, the winding tightening projects in the unit cell array direction. Since it is not included, it can be easily stored in the battery pack case 4, and the side plate 3
Is pressed in the stacking direction of the stacked electrode assembly 10 to stack the stacked electrode assembly 1
When improving the adhesion between the positive electrode 21a and the negative electrode 21b of 0, there is an advantage that the wound portion is less likely to be damaged by the above-mentioned pressurization and leak is less likely to occur.

Therefore, in this embodiment, since the side surface of the unit cell case is formed flexibly, charging and
The unit cell case is not affected by the expansion of the unit cell case due to the heat generated at the time of discharge, and does not need to have a rigid case structure for maintaining the pressing force of the laminated electrode body unlike the conventional case. Even if it is rolled up and assembled, it is not necessary to increase the plate thickness of the case, and the weight and size of the unit cell can be reduced. The winding tightening structure is not limited to one winding, but may be two windings or three windings in order to increase the strength. Further, as the term of winding and assembling described above, it is called winding tightening, but if the assembling method is the same, even if the name of the assembling method is different, a method by another name, for example, by another press working or caulking Methods can also be used.

Further, a fifth embodiment of the unit cell according to the present invention will be described. 13 is an exploded perspective view of the laminated electrode body of the present embodiment, FIG. 14 is a perspective view of a single cell, FIG. 15 is an exploded perspective view of a single cell, FIG. 16 is a cross-sectional view of an electrode terminal mounting structure,
FIG. 17 is a cross-sectional view for explaining the tightening work. In this embodiment, the laminated electrode body 10 is configured by laminating a plurality of positive and negative electrodes 21a and 21b with a film-like separator 21c interposed therebetween and winding them with an adhesive tape 11, as shown in FIG. Two negative electrode lead portions 14 and one positive electrode lead portion 13 are provided on the upper portion. The two lead portions 14 of the negative electrode are connected by a lead wire 22, and an insulating cover 23 is provided at the center of the lead wire 22. Lead members 24 and 25 are connected to the negative electrode lead portion 14 on the right side of FIG. 13 and the central positive electrode lead portion 13, respectively. Positive electrode and negative electrode terminal terminals 5 and 6 to be described later are connected to the respective lead members 24 and 25. An insertion hole 27 corresponding to the bolt hole 26 provided in the is provided. Incidentally, in FIG. 13, 2
Reference numeral 8 denotes an attachment piece for attaching the lead wire 22 or the lead members 24, 25 to the lead portions 13, 14 with bolts or the like.

Further, as shown in FIGS. 14 and 15, the unit cell case 4 for accommodating the laminated electrode body 10 seals a case portion 29 which bulges sideways and a side opening of the case portion 29. It is composed of two members such as the side plate 30. The side plate 30 is formed so as to be recessed toward the case portion 29 side except for the peripheral portion, and the bulging portion of the case portion 29 of another unit cell 1 can be fitted therein. The case portion 29 is formed by, for example, drawing, and the case portion 29 and the side plate 3 are formed.
0 is formed flexibly. Further, on the upper part of the case portion 29, the positive and negative electrode terminals 5, 6 are formed.
Is fixed. These electrode terminals 5 and 6 are shown in FIG.
As shown in FIG. 5, an insulating material 31 is interposed between the case portion 29 and a nut 32 so as to be fastened and fixed to the case portion 29. Bolt holes 26 for connecting the lead members 24, 25 are provided.

In order to store the laminated electrode body 10 in the unit cell case 4, the laminated electrode body 10 is inserted into the case portion 29, and the lead portion 13 is inserted by the bolt 33 through the insertion hole 27 and the bolt hole 26. , 14 lead members 24,
25 and each of the electrode terminals 5 and 6 are connected, and then, as shown in FIG. 17, the side plate 30 is applied to the peripheral edge of the opening of the case portion 29 with a compound material 34 such as polyethylene interposed therebetween.
The peripheral edge of the opening of the case portion 29 and the peripheral edge of the side plate 30 are assembled by winding or caulking and sealed, and the electrolytic solution is injected to form the unit cell 1. This embodiment also has the same effect as the fourth embodiment.

The method of tightening the winding will be described by taking the case of the fifth embodiment as an example. The winding is tightened by a general method as shown in FIG. 17 and the seaming chuck 35 and the first and second seaming rolls 36 and 37.
Is done using and. That is, when the tightening is to be protruded in the stacking direction of the laminated electrode body 10, as shown in FIG. 17, a compound material 34 such as polyethylene is inserted in the opening of the case portion 29 into which the laminated electrode body 10 is inserted. Side plate 3
18, the seaming chuck 35 is set on the peripheral portions of the side plate 30 as shown in FIG. 18, and the first seaming rolls 36 are applied to and pressed against both peripheral portions, so that the rough winding is performed. Tightening is performed, and then, as shown in FIG. 19, the second seaming roll 37 is pressed tightly to complete the winding. Further, the winding tightening is performed on the laminated electrode body 10.
In the case of protruding in a direction orthogonal to the stacking direction of
As shown in FIG. 21, after roughly tightening with the first seaming roll 36, it is completed with the second seaming roll 37 as shown in FIG.

Next, a third embodiment of the assembled battery structure according to the present invention will be described. In the present embodiment, the assembled battery structure 40 is configured by using the unit cells 1 of the fourth and fifth embodiments. That is, in the present embodiment, as shown in FIG. 22, the assembled battery case 41 is composed of a pair of side plates 42 and a frame 43 provided between the side plates 42, which are made of a rigid material. , And has a size capable of accommodating seven unit cells 1. Also,
The length of each frame 43 is formed to be shorter than the size of seven adjacent cells 1 arranged side by side.
The frame 43 and each frame 43 are connected to each other by a clamp type pressurizing spring 51 outside the case.

Therefore, the clamp type pressing spring 51 is used.
The both side plates 42 are pressed from both sides by the urging force of the laminated electrode bodies 10 of the seven unit cells 1 housed therein in the stacking direction. Therefore, the rigidity of the unit cell case itself can be reduced. For example, when the unit cell case 4 is formed of stainless steel, the plate thickness is 0.3 to
The thickness can be reduced to 0.4 mm, the weight and size of the unit cell 1 can be greatly promoted, and the energy volume density and the weight density can be increased as in the above embodiment.

[0034]

As described above, according to the present invention, since the side surface of the unit cell case is formed flexibly, it is not necessary to form the unit cell case with a rigid member, and the unit cell itself is lightened. In addition, it is possible to reduce the size, and even if the cell case is rolled up and assembled, there is no need to increase the plate thickness of the cell case, and the expansion of the cell case due to the heat generated during charging and discharging as in the past Is not affected, and a rigid case structure for holding the pressure applied to the laminated electrode body is not required, which facilitates the production of the unit cell. Further, since the pressurizing spring is provided in the battery pack case, the pressure-bonding property of the laminated electrodes in the plurality of cells arranged in the battery pack case is improved, a sufficient capacity is obtained, and the cycle of the battery pack structure is improved. It is possible to obtain a single cell and an assembled battery structure having improved characteristics and high energy volume density and weight density.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a single battery according to a first embodiment of the single battery.

FIG. 2 is an exploded perspective view of a single battery according to a second embodiment of the single battery.

FIG. 3 is a perspective view of a single battery according to a third embodiment of the single battery.

FIG. 4 is an exploded perspective view of an assembled battery case according to the first embodiment of the assembled battery structure.

FIG. 5 is an exploded perspective view of an assembled battery case according to a second embodiment of the assembled battery structure.

FIG. 6 is an exploded perspective view of a single battery according to a fourth embodiment of the single battery.

FIG. 7 is a perspective view of a unit cell.

FIG. 8 is a schematic sectional view of a unit cell showing a winding structure.

FIG. 9 is a schematic sectional view of a unit cell showing a winding structure.

FIG. 10 is a schematic sectional view of a unit cell showing a winding structure.

FIG. 11 is a schematic cross-sectional view of a unit cell showing a winding tightening structure.

FIG. 12 is a schematic sectional view of a unit cell showing a winding tightening structure.

FIG. 13 is an exploded perspective view of a laminated electrode body according to a fifth embodiment of a unit cell.

FIG. 14 is a perspective view of a single battery.

FIG. 15 is an exploded perspective view of a unit cell.

FIG. 16 is a cross-sectional view showing a mounting structure of an electrode terminal.

FIG. 17 is a cross-sectional view illustrating a winding operation.

FIG. 18 is a cross-sectional view illustrating a winding tightening operation.

FIG. 19 is a cross-sectional view illustrating a winding tightening operation.

FIG. 20 is a cross-sectional view illustrating a winding tightening operation.

FIG. 21 is a cross-sectional view illustrating a winding tightening operation.

FIG. 22 is a perspective view of an assembled battery structure according to a third embodiment of the assembled battery structure.

FIG. 23 is an exploded perspective view of a conventional single cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Single battery 2 Body part 3,30 Side plate 4 Single battery case 10 Laminated electrode body 21a, 21b Electrode 29 Case part 40 Assembly battery structure 41 Assembly battery case 46 Pressing spring

Claims (7)

[Claims] 1. A flat unit cell in which a laminated electrode body in which flat plate-shaped or sheet-shaped electrodes are laminated is housed in a unit cell case, wherein the unit cell case is parallel to an electrode surface of the laminated electrode body. A single cell, wherein at least one side surface of both side surfaces is formed into a flexible thin plate. 2. The unit cell according to claim 1, wherein at least two or more battery terminals are provided on a side surface of the unit cell case parallel to the stacking direction of the stacked electrode body. 3. The unit cell according to claim 1, wherein the unit cell case is composed of a plurality of members, and peripheral portions of the plurality of members are wound around each other and assembled and sealed. 4. The unit battery case includes a tubular body portion,
4. The unit cell according to claim 3, which is composed of both side plates that seal the openings on both sides of the body portion, and the peripheral portions of the body portion and the side plates are wound around each other and assembled. 5. The unit cell according to claim 4, wherein the unit cell case portion, in which the peripheral portions of the body portion and the side plates are wound around each other and assembled, is projected in a direction orthogonal to the stacking direction of the stacked electrode body. . 6. The unit cell case is composed of a case portion in which a tubular body portion and one side plate are integrated with each other, and a side plate which seals an opening of the case portion. The unit cell according to claim 3, wherein the peripheral portions are wound around each other and assembled. 7. A flexible thin plate having at least one of the side surfaces parallel to the electrode surface of the laminated electrode body of the unit cell case accommodating the laminated electrode body in which flat or sheet-shaped electrodes are laminated. In the assembled battery structure in which the plurality of unit cells formed in the above are arranged and housed in the assembled battery case with the electrode surfaces of the individual cells parallel to each other, at least from one side of the assembled battery case 2. A battery pack structure, comprising a pressing spring for pressing the cells in the arrangement direction.