JP2002141055A - Tabular layered battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the position of the leads to be established as appropriate according to the condition of outside equipment without degrading the battery efficiency, while suppressing the complication of manufacturing in the tabular layered battery. SOLUTION: In the tabular layered battery in which tabular unit cell elements 10 are formed plural layers in lamination in the housing, the battery element 1 is constructed in such a way that the tabs 13A, 13B that are provided in each unit cell element are connected with each other in the housing, respectively. The leads 3A, 3B that are connected electrically with the battery element 1 in the housing are drawn out to the outside of the housing from the prescribed positions that are different from the mounting positions of the tabs 13A, 13B in plan view.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat plate type battery in which a plurality of flat unit battery elements are stacked in a housing.

[0002]

2. Description of the Related Art Conventionally, batteries having various structures have been developed, and examples of such battery structures include a wound type and a flat plate type. The wound type battery is configured by winding unit battery elements 210 as shown in FIG. 10, and the flat plate type battery is formed by stacking a plurality of flat unit battery elements 10 as shown in FIG. It is constituted by. Reference numerals 13A and 13B denote unit battery elements 10
Are electrically connected to the tab.

[0003]

By the way, the mounting position of the lead for connecting the battery to an external electric device is as follows.
It is set according to the conditions on the electrical device side. However, in the above-mentioned wound type battery, as shown by a solid line in FIG.
Leads 203A, 2 for extracting electricity from the battery element
The structure 03B is structurally pulled out from the lamination surface (see FIG. 10) formed by winding the battery element 201. For this reason, in FIG. 11, in order to pull out the leads 203A and 203B as shown by the solid lines, the battery element having the width L1 is wound. On the other hand, as shown by the two-dot chain line, the leads 203A and 203B are drawn out. Has a structure in which a battery element having a width L2 is wound. Therefore, even if the batteries have substantially the same plane dimensions, the leads 203A, 20A
There is a problem that it is necessary to manufacture battery elements having completely different dimensions depending on whether the 3B is attached to either the long side or the short side. In FIG. 10, the leads 203A, 203
B is omitted.

In the flat plate type battery, the tabs 13A and 13B of each unit cell element 10 are shown only in the negative side tab 13B in FIG. 13, but they are superposed inside the housing 2 and electrically connected to each other. It is configured as a terminal. In addition, these bipolar terminals are respectively connected to one end of a lead (only the negative electrode lead 103B is shown in FIG. 13) inside the housing 2, and the other end of each lead is drawn out of the housing and is connected to the outside. Electrical equipment.

As shown in FIGS. 13 and 14, each unit cell element 10 of the flat plate type battery includes a positive electrode 10A, a negative electrode 10B, and a separator 10C interposed between the positive electrode 10A and the negative electrode 10B. Have been. FIG.
As shown in FIG. 3, each of the electrodes 10A and 10B
A and 12B are formed by forming polar material layers 11A and 11B on one or both sides (one side in this case) of tabs 13A and 13B.
B is formed by extending the current collectors 12A and 12B.
In the flat plate type battery, only the positions of the tabs on the current collectors 12A and 12B are corrected, and as compared with the wound type battery, FIG.
As shown in (A) and (B), the mounting positions of the tabs 13A and 13B and the leads 103A and 103B can be easily changed to either the long side or the short side.

However, as shown in FIG. 13, the tabs 13A and 13B and the leads 103 are provided inside the housing 2.
A, width (joining width) W for superimposing and joining 103B
Are required, the tabs 13A and 13B and the lead 10
When 3A and 103B are attached to the long side of the battery, the tab 13
There is a problem that a space (hereinafter, referred to as a dead space) _SD that does not contribute to power generation in the battery increases as compared with the case where the A, 13B and the leads 103A, 103B are attached to the short sides of the battery.

That is, as shown in FIG.
3A, 13B and the lead 103A, when mounting the 103B to the short side, the dead space S _D, compared to which in turn are multiplied by a short side dimension L _S and bonding width W battery and thickness, 15
Tabs 13A and 13B and leads 10 as shown in FIG.
When 3A and 103B are attached to the long sides, the dead space _SD is multiplied by the long side dimension _LL , the junction width W, and the battery thickness, and increases.

Therefore, the tabs 13A and 13B and the leads 103A and 103B are attached to the short sides, and the tabs 13A and 13B and the leads 103A and 103B
Is attached to the long side, if the size of the battery is fixed,
If the battery capacity is reduced and the battery capacity is kept constant, the battery size is increased (the battery efficiency is reduced).

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and it is possible to appropriately set the positions of the leads according to the conditions on the external device side without reducing the battery efficiency while suppressing the production complexity. It is an object of the present invention to provide a flat plate type battery as described above.

[0010]

SUMMARY OF THE INVENTION For this reason, a flat plate type battery of the present invention (claim 1) is a flat plate type battery comprising a plurality of flat unit battery elements stacked in a housing. Tabs provided on each unit battery element are electrically connected to each other in the housing to form a battery element, and leads electrically connected to the battery element in the housing are formed by the tabs in plan view. Is drawn out of the housing from a predetermined position different from the mounting position.

The flat-plate type battery of the present invention (Claim 2) is:
A positive electrode, a negative electrode, and a flat plate type battery configured by stacking a plurality of flat unit battery elements each including an electrolyte layer interposed between the positive electrode and the negative electrode in a housing, Along with the unit battery element, a positive-side plate-shaped conductor having the same shape as the positive-side current collector constituting the positive electrode of the unit battery element, and a negative-side current collector constituting the negative electrode of the unit battery element The negative electrode side plate-shaped conductor of the shape is laminated,
The tab of each positive electrode side current collector and the tab of the positive electrode side plate-shaped conductor are electrically connected in the housing, and the positive electrode side lead is electrically connected to the positive electrode side plate-shaped conductor. Are pulled out of the housing at a first predetermined position different from the mounting position of the tab of the positive electrode side current collector and the tab of the positive electrode side plate-shaped conductor in plan view, and the respective negative electrode side current collectors The tab and the tab of the negative electrode-side plate-shaped conductor are electrically connected in the housing, and the negative electrode-side lead electrically connected to the negative electrode-side plate-shaped conductor, The tab is drawn out of the housing at a second predetermined position different from the mounting position of the tab of the negative electrode side current collector and the tab of the negative electrode side plate-shaped conductor.

In this case, an insulating adhesive layer is interposed between the positive-side plate-shaped conductor and the negative-side plate-shaped conductor,
It is preferable that the positive-electrode-side plate-shaped conductor and the negative-electrode-side plate-shaped conductor are formed integrally (claim 3). Also,
It is preferable that the adhesive layer is formed in the same specification as the electrolyte layer (claim 4).

It is preferable that the tab is formed on a short side of the unit battery element, and the lead is formed on a long side of the unit battery element.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 to FIG. 8 are views showing a flat plate type battery as one embodiment of the present invention.
Further, FIG. 14 used in the description of the related art will be described. In the present embodiment, an example in which the flat-plate battery of the present invention is applied to a lithium battery will be described. (A) Principal Configuration The flat-plate lithium battery according to the present invention (hereinafter simply referred to as a flat-plate battery) has a battery element 1 shown in FIG. 1 inside a flexible housing 2 as shown in FIG. It is housed and configured. The battery element 1 includes a plurality of flat unit battery elements (unit cells) 1 as described later with reference to FIGS.
Zero and one dummy cell 10 '(the dummy cell 10' will be described later) are stacked.

As shown in FIG. 4, the housing 2 includes a cover 2a and a housing 2b. After the battery element 1 is housed in the recess of the housing 2b, the peripheral portion 21a of the cover 2a and the housing 2b are closed. After being overlapped with the peripheral portion 21b, it is formed by vacuum sealing. Then, the leads 3 electrically connected to the battery element 1 from the mating surfaces of the peripheral portions 21a and 21b.
A, 3B are tabs 13A, 1 described later in plan view.
It is exposed from a predetermined position different from the mounting position of 3B (here, from the long side of the battery element 1), and is electrically connected to an external device (not shown) outside the housing 2.

In the battery element 1, as shown in FIGS. 1 and 3, a flat unit battery element 1 is used to increase the capacity of the battery.
0 (three in this case) are stacked. Each unit battery element 10 includes a positive electrode 10A, a negative electrode 10B, and an electrolyte layer 10C interposed between the positive electrode 10A and the negative electrode 10B. In addition, the unit battery element 10 has a forward posture in which the positive electrode 10A is on the upper side and the negative electrode 10B is on the lower side in FIG. 3, and a reverse configuration in which the negative electrode 10B is on the upper side and the positive electrode 10A is on the lower side in FIG. Some of the posture.

In the battery element 1, by alternately stacking the unit battery elements 10 having these different postures, the unit battery elements 10, 10 adjacent in the stacking direction have the same polarity (that is, the positive electrode 10A and the positive electrode 10A). 10A or the negative electrode 10B and the negative electrode 10B). As shown in FIG. 1, a tab 13A made of aluminum is provided on the short side of the positive electrode 10A, and a tab 13B made of copper is provided on the short side of the negative electrode 10B. And here,
The unit battery elements 10 are connected in parallel. Therefore, similarly, the tabs 13B on the positive electrode side of each of the stacked unit battery elements 10 are similarly stacked so that the tabs 13B on the negative electrode side of each of the stacked unit battery elements 10 are easily polymerized and bound.
In each of the unit battery elements 10, in each of the unit battery elements 10, each of the positive electrode tabs 13 </ b> A is located on the lower side in the drawing and each of the negative electrode tabs 13 </ b> B is located in the drawing so as to be easily polymerized and bound. , Each unit battery element 10 is formed so as to be on the upper side.

Therefore, as described above, the unit cell element 1
0 includes a stack in a forward orientation and a stack in a reverse orientation.
When the tabs 13A and 13B are viewed from above in a posture in which the tabs 13A and 13B are directed upward with the negative electrode 10B facing downward, the positive electrode side tab 13A
Is formed on the right side (therefore, this unit battery element 10 is referred to as a light type (hereinafter, simply referred to as an R type) or an R type unit battery element 10).
The tabs 13A, 1A are stacked in the reverse orientation, with the positive electrode 10A facing upward and the negative electrode 10B facing downward.
When viewed with 3B facing upward, the positive electrode side tab is formed on the left side (therefore, this unit battery element 10 is referred to as a left type (hereinafter abbreviated as L type) or an L type unit battery element 10). . Such a a a R type and L type, disposed between the positive electrode tab 13A and the negative electrode tab 13B has a symmetrical structure with respect to the center line C _L.

By adopting such a structure, as described above, when these unit cell elements 10 are stacked upside down (in the thickness direction) (ie, R
When the positive electrode is set to the upper side and the negative electrode is set to the upper side in the L type, or when the negative electrode is set to the upper side in the R type and the positive electrode is set to the upper side in the L type), the positive electrode tab 13A and the negative electrode tab 13B are connected. Each has a structure that is easily concentrated and concentrated on one side.

In FIG. 3, the cathode 10 is simplified.
A, the negative electrode 10B, and the electrolyte layer 10C are all shown in the same plane dimensions, but the negative electrode 10B is formed so as to have a periphery larger than the periphery of the positive electrode 10A.
C is further formed to have a periphery larger than the periphery of the negative electrode 10B. In other words, by forming the negative electrode 10B larger than the positive electrode 10A (forming the peripheral edge of the negative electrode 10B larger than the peripheral edge of the positive electrode 10A), deposition of an electromotive substance (lithium in the case of a lithium battery) of the flat-plate stacked battery That is, dendrite can be suppressed.

The electrolyte layer 10C is formed by filling the gaps of a porous spacer with an electrolyte, and has a function of separating the positive electrode 10A from the negative electrode 10B to prevent a short circuit. This electrolyte layer 10C (spacer) is
0A and the anode 10B (the electrolyte layer 10C
Are formed larger than the periphery of the positive electrode 10A and the periphery of the negative electrode 10B).
And a short circuit caused by contact between the positive electrode 10A and the negative electrode 10B can be prevented.

Here, the dummy cell 10 ', which is a major feature of the present invention, will be described. As described below, the dummy cell 10 ′ has a configuration in which the unit battery element 10 does not have an extreme material layer and does not have a battery function.
It is called a dummy cell because it looks similar to the unit battery element (unit cell) 10. As shown in FIG. 3, the dummy cell 10 'includes a positive plate-like conductor 12A', a negative plate-like conductor 12B ', and a positive plate-like conductor 12B'.
A 'and an adhesive layer 10C' interposed between the negative-electrode-side plate-shaped conductor 12B ', and the same as the unit cell element 1 and the electrode of the adjacent unit cell element 1. In a posture where the plate-shaped conductor on the pole side faces (that is, the positive electrode 1
2A and the positive electrode side plate-shaped conductor 12A 'or the negative electrode 12B
And the negative and positive electrode side plate-shaped conductors 12A 'are stacked in a facing position.

The adhesive layer 10C 'may be any material having an insulating property as well as an adhesive property. The positive electrode side plate-shaped conductor 12A 'and the negative electrode side plate-shaped conductor 12B' are formed by the adhesive layer 10C '.
By integrally bonding and bonding, the positional relationship between the positive-side plate-shaped conductor 12A 'and the negative-side plate-shaped conductor 12B', and thus the positional relationship between the leads 3A and 3B, is defined. Positive-side plate-shaped conductor 12A 'and negative-side plate-shaped conductor 12 when assembling battery element 1
The alignment with B 'becomes unnecessary.

The electrolyte layer 10C of the unit cell element 1
However, if the electrolyte solution is held by a polymer and provided with a gel electrolyte having an adhesive property, the same configuration as the electrolyte layer 10C, that is, in the gap of the porous insulating spacer, A configuration in which a gel electrolyte is filled may be used. Thus, the adhesive layer 10C 'and the electrolyte layer 10
By setting C and C to the same specification, the manufacturing process is shared, and further, it is ensured that the adhesive layer 10C 'does not adversely affect the battery performance.

Here, the positive electrode side plate-like conductor 12
A ′ is formed in the same material (here, aluminum material) and shape as the positive electrode side current collector 12A constituting the positive electrode 10A, and when stacked to constitute the battery element 1, FIGS. As shown in FIG. 2, on the short side of the unit battery element 1, the tab 13A 'is formed to extend so as to be at the same position (planar position) as the tab 13A of the positive electrode current collector 12A in plan view. ing. Similarly, the negative electrode side plate-shaped conductor 12
B ′ is formed of substantially the same material (in this case, copper material) and shape as the negative electrode-side current collector 12B, and when stacked to constitute the battery element 1, the short side of the unit battery element 1 In FIG. 7, a tab 13B 'is formed to extend so as to be located at the same position as the tab 13B on the negative electrode side in plan view.

Further, as shown in FIG. 2, a tab 13A 'in plan view is formed on the positive electrode-side plate-like conductor 12A'.
A first predetermined position different from the mounting position (here,
The lead 3A is formed to extend on the long side of the unit battery element). Similarly, as shown in FIG. 2, a tab 13B 'in a plan view is formed on the negative electrode-side plate-like conductor 12B'.
A second predetermined position different from the mounting position (here,
The lead 3B is formed to extend from the long side of the unit battery element).

As shown in FIG. 1, when forming the battery element 1, the tab 13A 'is superposed on the positive electrode side tab 13A of each unit battery element. Similarly, when constituting the battery element 1, the tab 13B 'is superposed on the negative electrode side tab 13B of each unit battery element. Thereby, each unit battery element 1
0 are electrically connected to each other to form a large-capacity battery element 1, and the leads 3A and 3B are electrically connected to each unit battery element 10 via the planar conductors 12A 'and 12B'. .

In the flat plate type battery, since the tabs 13A and 13B of the plurality of unit battery elements 10 are superposed and bound,
A predetermined width W (see FIG. 2) is required to overlap the tabs 13A and 13B, and as described above as a problem of the related art, this width W causes a dead space S that does not contribute to power generation. Here, the leads 3A and 3B are connected to the long sides (dimension L in FIG. 2) according to the conditions required from the device side.
_L side). For this reason, for example, when the tabs 13A and 13B of the unit battery element 10 are provided on the long sides, respectively, the dead space S becomes the longitudinal dimension L
_In the present embodiment, the leads 3A and 3B are drawn out from the long side, but the tabs 13A and 13B are each formed on the short side (see FIG. 4). 2, the dead space S is a product of the dimension L _S , the width W, and the thickness of the unit battery element 10 because it is provided on the side indicated by the dimension L _S , L _S <L _L ). Therefore, the increase in the dead space S can be suppressed as compared with the case where the tabs 13A and 13B are provided on the long sides, respectively.

Of course, the thickness of the dummy cell 10 'is a dead space having no battery function, but this dead space is extremely small compared to the reduction of the dead space S due to the use of the dummy cell 10'. The increase in the dead space can be suppressed. In particular, when the number of stacked single battery elements is increased, the thickness of one dummy cell 10 'has little effect on the battery element 1, and on the other hand, the joined tabs 13A, 13A
Since the amount of B increases and the width W increases, the effect of using the dummy cell 10 'becomes significant.

As described above, the leads 3A and 3B are formed by extending the plate-shaped conductors 12A 'and 12B' and integrally forming them with the plate-shaped conductors 12A 'and 12B'. Although it is preferable from the viewpoint of conductivity between the bodies 12A ', 12B' and the leads 3A, 3B, the leads 3A, 3B may be electrically connected to the flat conductors 12A ', 12B', and thus the battery element 1. . For example, leads 3A, 3
B may be configured to be joined to the planar conductors 12A 'and 12B'. In this case, the leads 3A and 3B are made of the same material as the plate-shaped conductors 12A 'and 12B' so as not to cause electrolytic corrosion.
Are made of an aluminum material, and the leads 3B are made of a copper material). (B) Peripheral Configuration Now, the housing 2, the positive electrode 10A, the negative electrode 10B,
The electrolyte layer 10C will be further described.

First, the housing 2 will be described.
The structure of the housing 2 may be any structure as long as it has mechanical strength and sealing properties. In addition to the structure shown in FIG. 4 described above, for example, FIGS.
The housings 2 ', 4, 14 as shown in FIG. A housing 2 'shown in FIG. 5 is different from the housing 2 shown in FIG. 4 in that a lid 2a and a housing 2b are separately formed. A housing 4 shown in FIG. 4a and 4b are continuously formed so as to be bendable. Further, as shown in FIG. 7A, one sheet-shaped housing 14 is folded in two around the center side 14a to form a first housing.
The battery element 1 is interposed between the piece 14A and the second piece 14B, and the periphery of the first piece 14A and the periphery of the second piece 14B are joined as shown in FIG. May be enclosed.

As shown in FIGS. 4 to 7, it is preferable to seal the stacked housings in view of ease of manufacture and battery performance such as battery capacity. In this case, the leads 3A and 3B can be easily exposed to the outside from the sealing portion of the housing. Exposing the lead from the sealing portion of the housing is a preferable aspect in that the electrical connection with the battery element 1 housed therein is easy, and as a result, the yield and safety of the battery are improved.

Further, the housing preferably has shape changeability, since it is easy to change the shape of the battery in various ways. Further, when the battery element 1 is accommodated in the housing and the outer edge of the housing is sealed, it is preferable that the inside of the housing is evacuated before the sealing. Thereby, a pressing force can be applied to the battery element 1, and battery characteristics such as cycle characteristics can be improved.

As a material for the housing, a metal such as aluminum or nickel-plated iron or copper, or a synthetic resin can be used. It is preferable to use a flexible film-like composite material (for example, a laminate-like composite material (laminated film)) on which is laminated. By using the laminated composite material, the thickness and weight of the members constituting the housing can be reduced, and the capacity of the battery as a whole can be improved.

FIG. 8 shows a laminated composite material.
As shown in (A), a laminate of a metal layer 5 and a synthetic resin layer 6 can be used. This metal layer 5
Prevents infiltration of water or maintains shape retention. It can be used for simple metals such as aluminum, iron, copper, nickel, titanium, molybdenum and gold, alloys such as stainless steel and Hastelloy, and metal oxides such as aluminum oxide. Good, but particularly preferred is aluminum having excellent workability. The metal layer 5 can be formed by a metal foil, a metal deposition film, a metal sputter, or the like.

The synthetic resin 6 is used to prevent the metal layer 5 from contacting the battery element 1 or the like or to protect the metal layer 5, and the elastic modulus and the tensile elongation are particularly limited. However, it also includes what is generally called an elastomer. As the synthetic resin 6, a thermoplastic, a thermoplastic elastomer, a thermosetting resin and a plastic alloy are used. These resins include those in which a filler such as a filler is mixed.

FIG. 8B shows a laminated composite material.
As shown in the figure, a synthetic resin layer 6A functioning as an outer protective layer is provided on the outer surface of the metal layer 5, and corrosion by the electrolyte, contact between the metal layer 5 and the battery element 1 is prevented on the inner surface, and the metal layer 5 is protected. Resin layer 6 functioning as an inner protective layer for
B and a three-layer structure in which B is laminated. In this case, as the resin 6A used for the outer protective layer, a resin excellent in chemical resistance and mechanical strength such as polyethylene, polypropylene, modified polyolefin, ionomer, amorphous polyolefin, polyethylene terephthalate, and polyamide is used. desirable. On the other hand, as the resin 6B used for the inner protective layer, a synthetic resin having chemical resistance is used, for example, polyethylene, polypropylene, modified polyolefin,
An ionomer, an ethylene-vinyl acetate copolymer, or the like can be used.

FIG. 8C shows a laminated composite material.
As shown in the figure, a metal layer 5 and a protective layer forming synthetic resin 6A
The adhesive 7 may be interposed between each other and the inner protective layer synthetic resin layer 6B. Furthermore, an adhesive layer made of a weldable resin such as polyethylene or polypropylene may be provided on the innermost surface of the composite material in order to bond the connection portion (sealing portion) of the housing member.

The housing may be formed by fusing the periphery of the film, or the sheet may be drawn by vacuum forming, pressure forming, press forming or the like. Further, it can be molded by injection molding a synthetic resin. When injection molding is used, the metal layer is usually formed by sputtering or the like. Next, the positive electrode 10A and the negative electrode 10B will be described with reference to FIG. 14. As described above as the description of the related art, the positive electrode 10A has the positive electrode current collector 12A as a core material on one surface of the positive electrode current collector 12A. The positive electrode active material layer 11A is formed, and the negative electrode 10B is similarly formed with the negative electrode current collector 12B.
And a negative electrode active material layer 11B formed on one surface of the negative electrode current collector 12B. In addition, each positive electrode current collector 1
A positive electrode tab 13A extends from 2A, and similarly, a negative electrode tab 13B extends from each negative electrode current collector 12B.
The active material layers 11 are provided on both surfaces of the current collectors 12A and 12B.
A and 11B may be formed respectively.

As the current collectors 12A and 12B, generally, a foil made of metal is used. Here, the positive electrode current collector 12A (including the tab 13A) is used because of compatibility with the active material layers 11A and 11B. Aluminum as the negative electrode current collector 12
Copper is used as B (including the tab 13B). The thickness of the current collectors 12A and 12B is appropriately selected. However, if the thickness is too small, the mechanical strength becomes weak, so that processing becomes difficult and the productivity is lowered. The energy density is preferably in the range of 1 to 30 μm because there is a possibility of lowering the energy density as a whole.

The current collectors 12A and 12B and the active material layer 1
In order to increase the adhesive strength with 1A and 11B, active material 11
Before applying A and 11B, the surfaces of the current collectors 12A and 12B are preferably roughened in advance. Examples of such a surface roughening method include a mechanical polishing method and an electrolytic polishing method. And a chemical polishing method. As a mechanical polishing method,
For example, there is a method in which the surface of the current collector is polished with a wire brush provided with abrasive cloth, abrasive stone, emery buff, steel wire or the like to which abrasive particles are fixed. In addition, each current collector 12A, 1
2B is made of a plate-like member, a net-like member, a punching metal, or the like.

The positive electrode active material layer 11A contains a positive electrode active material. As the positive electrode active material, an inorganic compound or an organic compound can be used as long as it can occlude and release lithium ions. Examples of the inorganic compound include a transition metal oxide, a composite oxide of lithium and a transition metal, and a chalcogen compound such as a transition metal sulfide. Here, the transition metal is Fe,
Co, Ni, Mn, etc. are used. Specifically, Mn
Transition metal oxides such as O, V ₂ O ₅ , V ₆ O ₁₃ and TiO ₂ ; composite oxides of lithium and transition metals such as lithium nickelate, lithium cobaltate and lithium manganate; Ti
Transition metal sulfides such as S ₂ , FeS, and MoS ₂ are exemplified. These compounds may be partially substituted with elements in order to improve their properties. Examples of the organic compound include polyaniline, polypyrrole, polyacene, disulfide-based compounds, and polysulfide-based compounds. These inorganic compounds and organic compounds may be mixed and used as the positive electrode active material. Preferably,
It is a composite oxide of lithium and at least one transition metal selected from the group consisting of cobalt, nickel and manganese.

The particle size of the positive electrode active material may be appropriately selected in consideration of the other components of the battery.
Usually, it is preferably from 1 to 100 μm, particularly preferably from 2 to 60 μm, because battery characteristics such as initial efficiency and cycle characteristics are improved. The negative electrode active material layer 11B contains a negative electrode active material. As the negative electrode active material, a carbon-based material such as graphite and coke is usually used as a material capable of inserting and extracting lithium ions. Such a carbon-based material can also be used in the form of a mixture or coating with a metal, a metal salt, an oxide, or the like. In addition, as the negative electrode material, silicon, tin, zinc, manganese, iron, nickel and other oxides and sulfates, metallic lithium,
Lithium alloys such as Li-A1, Li-Bi-Cd, and Li-Sn-Cd, lithium transition metal nitrides, and silicon can also be used. Preferably, it is graphite or coke in terms of capacity.

If the particle size of the negative electrode active material is too large, the electron conductivity deteriorates, and from the viewpoint of improving the battery characteristics such as initial efficiency, late characteristics and cycle characteristics, the average particle size of the negative electrode active material is
The upper limit is usually 12 μm or less, preferably 10 μm.
m, and the lower limit is usually 0.5 μm or more, preferably 7 μm or more. In order to bind the positive electrode active material and the negative electrode active material to the current collectors 12A and 12B and to each other, it is preferable to mix a binder in the positive electrode active material layer 11A and the negative electrode active material layer 11B. As the binder, inorganic compounds such as silicate and glass, and various resins mainly composed of polymers can be used.
Examples of the resin include alkane-based polymers such as polyethylene, polypropylene, and poly-1,1-dimethylethylene; unsaturated polymers such as polybutadiene and polyisoprene; polystyrene, polymethylstyrene, polyvinylpyridine, and poly-N-vinylpyrrolidone. Acrylic polymers such as polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl acrylate, polyacrylic acid, polymethacrylic acid, polyacrylamide; polyfluorinated Fluorinated resins such as vinyl, polyvinylidene fluoride and polytetrafluoroethylene;
CN group-containing polymers such as polyacrylonitrile and polyvinylidene cyanide; polyvinyl alcohol-based polymers such as polyvinyl acetate and polyvinyl alcohol; halogen-containing polymers such as polyvinyl chloride and polyvinylidene chloride; and conductive polymers such as polyaniline can be used. . Further, a mixture of the above-mentioned polymers and the like, a modified product, a derivative, a random copolymer, an alternating copolymer, a graft copolymer, a block copolymer and the like can be used.

If the amount of the binder is too small, the strength of the electrode may be reduced. On the other hand, if the amount of the binder is too large, the capacity or the rate characteristic may be reduced. The amount of the binder relative to 100 parts by weight of the substance is preferably 0.1 to 30 parts by weight.
More preferably, it is 15 parts by weight. Also, the active material layer 1
In 1A and 11B, various kinds of conductive materials, reinforcing materials and the like are not particularly limited as required, but usually, acetylene black,
Examples include carbon powder such as carbon black and graphite, and various metal fibers and foils. Additives include trifluoropropylene carbonate, vinylene carbonate, 1,6-dioxaspiro [4,4] non
Ane-2,7-done, 12-crown-4-ether and the like can be used to increase the stability and life of the battery. As the reinforcing material, various inorganic or organic spherical or fibrous fillers can be used.

The active material layers 11A and 11B are connected to the current collector 12A,
As a method of forming on the 12B, for example, a powdery active material is mixed with a solvent together with a binder, and this is dispersed and coated using a ball mill, a sand mill, a twin-screw kneader, or the like. There is a method of applying and drying on 12A and 12B. In this case, the type of the solvent used is not particularly limited as long as it is inert to the active material and can dissolve the binder. For example, a commonly used inorganic solvent such as N-methylpyrrolidone or the like can be used. Any of organic solvents can be used.

In a state where the active material is mixed with the binder and heated to be softened, the active material is pressed or sprayed onto the current collectors 12A and 12B to thereby form the current collector 12
A layer of an active material can be formed on A and 12B. Alternatively, by sintering the active material alone on the current collectors 12A and 12B without mixing the binder, the current collector 12
Active material layers 11A and 11B can also be formed on A and 12B.

In the active material layer, an electrolyte similar to that used for an electrolyte layer 10C, which will be described later, is mixed to facilitate the movement of ions in the active material layer. The more electrolytes are mixed, the more easily the ions can move in the active material layers 11A and 11B. Therefore, the rate characteristics are preferable. On the other hand, the smaller the amount of the electrolyte, the higher the energy density. Therefore, the ratio of the electrolyte in the active material layer is 10%.
Preferably, it is set to と す る 50% by volume.

The thickness of each of the active material layers 11A and 11B is preferably thicker in terms of capacity, but is preferably thinner in terms of late characteristics. For this reason, each active material 11A, 11B
The lower limit of the film thickness is usually 20 μm or more, preferably 30 μm or more, more preferably 50 μm or more, and most preferably 80 μm or more, while the upper limit is
It is usually at most 200 μm, preferably at most 150 μm.

Next, the electrolyte layer 10C will be described. As described above, the electrolyte layer 10C
And a negative electrode 10B, for example, is configured by impregnating a porous sheet with an electrolyte described later, and the thickness of the electrolyte layer 10C is generally 1 to 200 μm, preferably 5 to 200 μm.
５０50 μm. As the porous sheet, a sheet having a porosity of 10 to 95% is usually used.
It is preferable to use one of about 85%. In addition, as a material of the porous sheet, a stretched film, a nonwoven fabric, a woven fabric, or the like made of polyolefin or polyolefin in which some or all of the hydrogen atoms have been substituted with fluorine are used. The thickness of the porous sheet is usually 1 to
Those having a size of 200 μm, preferably 5 μm to 50 μm are used.

As the electrolyte impregnated in the porous sheet, various electrolytes such as a fluid electrolyte (hereinafter referred to as an electrolyte) and a non-fluid electrolyte such as a gel electrolyte and a completely solid electrolyte are used. You. From the viewpoint of the characteristics of the battery, it is preferable to use an electrolyte or a gel electrolyte, and from the viewpoint of safety, it is preferable to use a non-fluid electrolyte. In particular, when a non-fluid electrolyte is used, the liquid leakage can be more effectively prevented with respect to a battery using a conventional electrolytic solution. Therefore, as described above, the housing 2 containing the battery element 1 including the electrolyte layer 10C is used. Even if a material such as a laminate-like composite material having a thin film and a variable shape is used as the material, a high degree of safety is ensured.

As described above, the peripheral portion of the electrolyte layer 10C is formed so as to be larger than the peripheral portions of the positive electrode 10A and the negative electrode 10B. Is not so large that the electrolyte need not be present. Such an electrolyte,
The gel electrolyte and the completely solid electrolyte will be described.

First, an electrolytic solution applicable to the electrolyte layer 10C
Explaining that, the electrolytic solution usually disperses the supporting electrolyte.
It is produced by dissolving in an aqueous solvent. As a supporting electrolyte
Is safe for the positive and negative electrode active materials as electrolytes.
Constant and lithium ion is a positive electrode active material or a negative electrode
Can move to perform electrochemical reaction with active material
Any non-aqueous substance can be used
You. Specifically, LiPF ₆, LiAsF₆, LiSb
F₆, LiBF_Four, LiClO_Four, LiI, LiBr, L
iCl, LiAlCl, LiHF_Two, LiSCN, Li
S0_ThreeCF_TwoAnd the like. This
Among them, especially LiPF₆, LiClO_FourUse
Is preferred.

When a non-aqueous solvent is used as a solvent for these supporting electrolytes, the concentration is generally 0.5 to 2.5 m
An ol / L concentration of electrolyte is used. The non-aqueous solvent that dissolves these supporting electrolytes is not particularly limited,
It is preferable to use a solvent having a relatively high dielectric constant. Specifically, cyclic carbonates such as ethylene carbonate and propylene carbonate, acyclic carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, glymes such as tetrahydrofuran, 2-methyltetrahydrofuran and dimethoxyethane, and γ
Lactones such as butyrolactone, sulfur compounds such as sulfolane, nitriles such as acetonitrile, and the like are used. These solvents can be used alone or as a mixture of two or more.

In particular, any one of cyclic carbonates such as ethylene carbonate and propylene carbonate, and acyclic carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate is used, or any one of these is used. It is preferable to use a mixture of two or more. In addition, those in which some of the hydrogen atoms in the molecules of these solvents are substituted with halogen or the like can also be used.

Further, additives and the like may be added to these solvents. Examples of the additive include trifluoropropylene carbonate, vinylene carbonate, 1,6-
Dioxaspiro [4,4] nonane-2,7
-Dione, 12-crown-4-ether and the like,
It can be used to enhance the stability, performance and life of batteries.

Next, a gel electrolyte applicable to the electrolyte layer 10C will be described. The gel electrolyte is usually generated by holding the above-mentioned electrolyte solution with a polymer. That is, the gel electrolyte is generally one in which the electrolyte is held in a polymer network and the fluidity as a whole is significantly reduced. In such a gel electrolyte, the properties such as ion conductivity and the like are close to those of the above-mentioned electrolyte solution, but the fluidity and volatility are significantly suppressed and the safety is enhanced. If the ratio of the polymer in the gel electrolyte is too low, the electrolyte solution cannot be held, and there is a risk of liquid leakage. On the other hand, if the ratio is too high, the ionic conductivity tends to decrease and the battery characteristics tend to deteriorate. , 1
Preferably it is in the range of 50% by weight.

The polymer used for the gel electrolyte is not particularly limited as long as it is a polymer capable of forming a gel together with the electrolytic solution, and those produced by polycondensation of polyester, polyamide, polycarbonate, polyimide and the like. Polyurethane, polyurea, etc., produced by polyaddition, acrylic derivative polymers such as poly (methyl methacrylate), and addition polymerization of polyvinyls such as polyvinyl acetate, polyvinyl chloride, polyvinylidene fluoride, etc. Some are done.

Preferred polymers include polyacrylonitrile and polyvinylidene fluoride.
Here, the polyvinylidene fluoride includes not only a homopolymer of vinylidene fluoride but also a copolymer with another monomer component such as hexafluoropropylene. Also, acrylic acid, methyl acrylate, ethyl acrylate, ethoxyethyl acrylate, methoxyethyl acrylate, ethoxyethoxyethyl acrylate, polyethylene glycol monoacrylate, ethoxyethyl methacrylate, methoxyethyl methacrylate, ethoxyethoxyethyl methacrylate, polyethylene glycol monomethacrylate, N , N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl acrylate, glycidyl acrylate, allyl acrylate, acrylonitrile, N-vinylpyrrolidone, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, Diethylene glycol It dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, also be used an acrylic polymer obtained by polymerizing an acrylic derivative type, such as polyethylene glycol dimethacrylate. As described above, preferably, an acrylic polymer is used as the polymer,
Further, it is preferable to use the same acrylic polymer as the fixing material after solidification.

If the ratio of the weight average molecular weight of the polymer to the concentration of the polymer in the electrolyte is too low, the retention of the electrolyte is reduced (it becomes difficult to form a gel), and the electrolyte flows to the outside of the battery element. Furthermore, it leaks out of the housing (leakage)
On the other hand, if it is too high, on the other hand, the viscosity becomes excessively high, causing difficulty in the manufacturing process, or the ion conductivity is low due to the low proportion of the electrolytic solution, and the battery characteristics (for example, late characteristics) may be reduced. is there. For this reason, it is usually preferable to use a weight-average molecular weight in the range of 10,000 to 5,000,000, and the concentration of the polymer in the electrolytic solution is 0.1 to 0.5.
It is preferable to be in the range of 1% by weight to 30% by weight.

Next, a complete solid electrolyte applicable to the electrolyte layer 10C will be described. As the complete solid electrolyte, various solid electrolytes known so far can be used. For example, it can be formed by mixing the polymer used in the gel electrolyte and the supporting electrolyte salt at an appropriate ratio. In this case, in order to increase the conductivity, it is preferable to use a polymer having a high polarity and to have a skeleton having many side chains. (C) Function / Effect Since the flat plate type battery as one embodiment of the present invention is configured as described above, the following function / effect is obtained.

That is, as shown in FIG. 2, the leads 3A,
3B is attached to the battery element 1 via the dummy cell 10 'at a predetermined position different from the attachment position of the tabs 13A and 13B in plan view, and is pulled out of the housing 2. Therefore, even if the lead-out positions of the leads 3A, 3B are changed according to the conditions on the external device side, it can be dealt with simply by changing the lead-out positions of the leads 3A, 3B in the dummy cell 10 '. This has the advantage that the unit battery elements 10 of the same specifications can be used irrespective of the conditions on the external device side, and the complication of the manufacturing process of the unit battery elements 10 and hence the flat-plate stacked battery can be suppressed.

As shown in FIG. 2, the leads 3A, 3A
B is provided on the long side of the battery element 1 and includes tabs 13A, 13A.
Since A ', 13B, and 13B' are provided on the short side of the battery element 1, the tab 1 can be provided while satisfying the requirements of the external device.
There is an advantage that a decrease in battery efficiency due to a space (dead space) required for polymerization of 3A, 13A ', 13B, 13B' can be prevented. Also, as shown in FIG. 3, the positive-side plate-shaped conductor 12A 'and the negative-side plate-shaped conductor 12B' are adhered to each other by an adhesive layer 10C 'and integrally formed as a dummy cell 10'. Conductor 1
The positional relationship between 2A 'and the negative electrode-side plate-like conductor 12B' is maintained, so that it is not necessary to adjust the position each time when assembling the battery, and there is an advantage that the production can be performed efficiently.

Further, the adhesive layer 10C '
The use of the same specifications as the electrolyte layer 10C of 0 has the advantage that the manufacturing process can be shared. Furthermore, since it has the same specifications as the electrolyte layer 10C, there is an advantage that the adhesive layer 10C 'can be reliably prevented from adversely affecting battery performance. (D) Others The flat-plate type battery of the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the spirit of the invention.

For example, in the above embodiment, the lead 3
Although both A and 3B are configured to be attached to the long side of the battery element 1, the positions of the leads 3A and 3B are appropriately set in accordance with the conditions of the external device side. 3, the lead 3A is attached to the long side of the battery element 1 in the same manner as in the above-described embodiment, and the lead 3B
May be attached to the short side opposite to the tab 13B.

In the above-described embodiment, the adhesive layer 10C 'is interposed between the positive-electrode-side plate-shaped conductor 12A' and the negative-electrode-side plate-shaped conductor 12B '.
A 'and the negative-side plate-shaped conductor 12B' are integrally formed as a dummy cell 10 '. For example, the positive-side plate-shaped conductor 12A' and the negative-side plate-shaped conductor 12B 'are not provided with the adhesive layer 10C'. May be independently laminated together with the single cell element 10. In this case, each flat conductor 12
A ′ and 12B ′ have the same polarity as the adjacent unit cell element 10 (that is, the positive-side plate-shaped conductor 12A ′ has the positive electrode 12A,
For example, as shown in FIG. 9, the negative electrode side plate-shaped conductor 12B 'is laminated so as to be in contact with the negative electrode 12B).

As described above, the positive electrode-side plate-like conductor 1
When 2A 'and the negative-side plate-like conductor 12B' are used independently, the plate-like conductors 12A 'and 12B' do not have a battery function because no polar material layer is supported, but apparently the electrode It is called a dummy electrode because it is similar to 10A and 10B. Alternatively, instead of using the dummy cell 10 ', at least one unit battery element having the leads 3A and 3B attached at a predetermined position (for example, long side) different from the attachment position of the tab in plan view is used. May be. In this case, it is necessary to manufacture unit battery elements of different types, but the battery efficiency can be relatively improved as compared with the use of the dummy cell 10 'having no battery function.

Further, in the above-described embodiment, an example was described in which the flat-plate type battery of the present invention was applied to a lithium battery using lithium ions as an electromotive substance. Applicable to batteries.

[0069]

As described above in detail, according to the flat-plate type battery of the present invention (claim 1), the leads electrically connected to the battery element in the housing are formed in the unit battery element in plan view. Since the lead is pulled out of the housing from a predetermined position different from the attachment of the tab, there is an advantage that the lead pull-out position can be appropriately set according to the conditions of the external device without substantially changing the specifications of the battery element.

According to the flat plate type battery of the present invention (claim 2), the positive electrode lead electrically connected to the positive electrode plate conductor has a tab of the positive electrode current collector and a positive electrode in plan view. A first position different from the mounting position of the tab of the side plate-shaped conductor
The negative lead, which is drawn out of the housing from the predetermined position and is also electrically connected to the negative flat conductor, has a tab of the negative current collector and the negative flat conductor in plan view. The lead is pulled out of the housing at a second predetermined position different from the mounting position of the tab, so that the position of the lead can be set according to the conditions of the external device.

The positive-side plate-shaped conductor has the same shape as the positive-side current collector of the unit cell element, and the negative-side plate-shaped conductor has the same shape as the negative-side current collector of the unit cell element. Therefore, the manufacturing process of the flat conductor and the manufacturing process of the current collector can be shared, so that the manufacturing complexity can be suppressed.
Therefore, there is an advantage that the position of the lead can be appropriately set according to the conditions on the external device side while suppressing the production complexity.

In this case, an insulating adhesive layer is interposed between the positive-side plate-shaped conductor and the negative-side plate-shaped conductor, and the positive-side plate-shaped conductor and the negative-side plate-shaped conductor are integrated. By forming, the positional relationship between the positive-side plate-like conductor and the negative-side plate-like conductor can be defined, and these plate-like conductors are laminated together with the unit cell element to produce a plate-type laminated battery. In this case, there is no need to position the positive-side plate-shaped conductor and the negative-side plate-shaped conductor, and the manufacturing operation can be simplified (claim 3).

Further, by forming the adhesive layer with the same specifications as the electrolyte layer, the manufacturing process of the adhesive layer and the electrolyte layer can be shared, so that the manufacturing operation can be simplified and Can be reliably prevented from being adversely affected (claim 4). Also, the space required to polymerize the tab is a dead space that does not contribute to battery performance,
By forming the tab on the short side of the unit battery element and forming the lead on the long side of the unit battery element,
Such an increase in dead space can be suppressed, and a decrease in battery efficiency can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an enlarged main part configuration of a flat-plate stacked battery as one embodiment of the present invention.

FIG. 2 is an enlarged schematic plan view showing a configuration of a main part of a flat-plate stacked battery as one embodiment of the present invention.

FIG. 3 is a schematic longitudinal sectional view showing an enlarged main part structure of a flat plate type battery as one embodiment of the present invention.

FIG. 4 is a schematic perspective view showing an overall configuration of a flat-plate stacked battery as one embodiment of the present invention (tabs are not shown).

FIG. 5 is a schematic perspective view showing the overall configuration of another example of the housing according to the flat plate type battery as one embodiment of the present invention (tabs are not shown).

FIG. 6 is a schematic perspective view showing the entire configuration of another example of the housing according to the flat plate type battery as one embodiment of the present invention (tabs are not shown).

FIG. 7 is a diagram showing another example of the housing according to the flat-plate stacked battery as one embodiment of the present invention;
(A) is a schematic perspective view (tab not shown) showing the entire configuration, and (B) is a schematic plan view showing the entire configuration.

FIGS. 8A to 8C are schematic cross-sectional views showing, on an enlarged scale, the structure of components of a housing according to a flat plate type battery as one embodiment of the present invention.

FIG. 9 is an exploded schematic perspective view showing a configuration of a modification of the flat-plate type battery as one embodiment of the present invention.

FIG. 10 is a schematic perspective view showing an enlarged configuration of a general wound battery.

FIG. 11 is a diagram for explaining the problem of the wound battery, and is a schematic plan view showing the configuration of the wound battery in an enlarged manner.

FIG. 12 is a schematic perspective view showing an exploded configuration of a conventional flat-plate type battery.

FIG. 13 is a diagram for explaining a problem of a conventional flat plate type battery, and is a schematic cross-sectional view of a principal part showing an enlarged configuration of a joining portion between a tab and a lead.

FIG. 14 is a schematic cross-sectional view showing an enlarged configuration of a unit battery element of a general flat-plate type battery.

15A and 15B are diagrams for explaining the problem of the conventional flat plate type battery, in which FIG. 15A shows a state where tabs and leads are attached to the short sides of the battery element, and FIG. FIG. 4 is a view showing a state in which a tab and a lead are attached to a long side of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Battery element 2, 2 ', 4, 14 Housing 2a Lid 2b Housing 3A Positive lead 3B Negative lead 4a, 4b Housing 5 Metal layer 6, 6A, 6B Synthetic resin layer 10 Unit battery element 10' Dummy cell 10A Positive electrode 10B Negative electrode 10C Electrolyte layer 10C 'Adhesive layer 11A Positive electrode active material 11B Negative electrode active material 12A, 12B Current collector 12A' Positive-side flat conductor 12B 'Negative-side flat conductor 13A Positive-side tab 13B Negative-side tab 14A 1 piece 14B 2nd piece 14a Central side 21a, 21b Peripheral edge

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Noritaka Ibuki 3-10 Ushidori, Kurashiki-shi, Okayama Prefecture Mizushima Works, Mitsubishi Chemical Co., Ltd. F-term (reference) 5H029 AJ14 AK02 AK03 AK05 AK16 AL01 AL06 AL07 AL11 AL12 AM00 AM02 AM03 AM04 AM05 AM07 AM16 BJ04 BJ06 CJ06 DJ05 DJ07 DJ08 EJ12 HJ12

Claims (5)

[Claims] 1. A flat plate type battery comprising a plurality of flat unit battery elements stacked in a housing, wherein tabs provided on each unit battery element are electrically connected in the housing. A battery element is configured, and a lead electrically connected to the battery element in the housing is drawn out of the housing from a predetermined position different from a mounting position of the tab in a plan view. , A flat-plate type battery. 2. A flat plate formed by stacking a plurality of flat unit battery elements each including a positive electrode, a negative electrode, and an electrolyte layer interposed between the positive electrode and the negative electrode in a housing. In the stacked battery, the unit battery element, the positive-side plate-shaped conductor having the same shape as the positive-side current collector constituting the positive electrode of the unit battery element, and the negative-side collector constituting the negative electrode of the unit battery element A negative-electrode-side plate-shaped conductor having the same shape as the electric conductor is laminated, and the tab of each positive-electrode-side current collector and the tab of the positive-electrode-side plate-shaped conductor are electrically connected in the housing. A positive electrode lead electrically connected to the positive electrode plate conductor, the first electrode being different from a mounting position of the tab of the positive electrode current collector and the tab of the positive electrode plate conductor in plan view; Is pulled out of the housing at a predetermined position of the The tabs of the conductor and the tabs of the negative-side plate-shaped conductor are electrically connected in the housing, and the negative-side lead electrically connected to the negative-side plate-shaped conductor is in plan view. A flat-plate type battery, which is drawn out of the housing at a second predetermined position different from a mounting position of the tab of the negative electrode-side current collector and the tab of the negative electrode-side plate-shaped conductor. . 3. An electrically conductive adhesive layer is interposed between the positive electrode-side plate-shaped conductor and the negative electrode-side plate-shaped conductor to form the positive electrode-side plate-shaped conductor and the negative electrode-side plate-shaped conductor. 3. The flat-plate laminated battery according to claim 2, wherein and are integrally formed. 4. The flat plate type battery according to claim 3, wherein the adhesive layer is formed in the same specification as the electrolyte layer. 5. The battery module according to claim 1, wherein the tab is formed on a short side of the unit battery element, and the lead is formed on a long side of the unit battery element. 5. The flat-plate laminated battery according to any one of the above items 4.