JP2012069408A - Modularized electrochemical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modularized electrochemical element having high volume energy efficiency and safety in which a dimensional variation due to expansion or contraction of the electrochemical element can be absorbed even if the electrochemical element is expanded or contracted.SOLUTION: A modularized electrochemical element contains a plurality of stacked unit cells 20 in an enclosure 40, and adhesive thin film spacers 21 that are interposed between adjoining unit cells 20 and between the main surface of the cell 20 and the inner surface of the enclosure 40. Preferably the spacer 21 has a thickness of 50 μm or more and 5 mm or less.

Description

  The present invention relates to an electrochemical element module including a plurality of electrochemical elements each having a flexible packaging material.

  Electrochemical elements typified by lithium ion secondary batteries are widely used as power sources for portable devices such as mobile phones and notebook personal computers because of their high energy density. In addition, as the performance of portable devices increases, the capacity of lithium ion secondary batteries tends to increase further, and in order to further improve the energy density, an electrochemical element using a flexible laminate exterior material has been developed. Many are used.

  On the other hand, recently, with the improvement in performance of electrochemical devices, electrochemical devices have begun to be used as power sources other than power sources for portable devices. For example, electrochemical elements have begun to be used for power sources for automobiles and motorcycles, power sources for moving bodies such as robots, and the like.

  Further, when the electrochemical element is used for a power source for automobiles or motorcycles, a power source for a moving body such as a robot, etc., a plurality of electrochemical elements are combined and used as a module for further increasing the capacity. When electrochemical elements are modularized in this way, the dimensional stability of each electrochemical element is directly linked to the dimensional stability of the entire module, which in turn affects the safety of the entire module. It is necessary to further improve the dimensional stability of the element.

  For example, if the dimensional accuracy of each electrochemical element constituting the module fluctuates, it will cause a decrease in the fixing accuracy of each electrochemical element in the module, and if the module is subjected to vibration, etc., the safety of the module will be reduced. It will be connected. In particular, in an electrochemical element using a laminate outer packaging material, the internal pressure in the electrochemical element fluctuates due to the generation of gas accompanying charging / discharging or the use temperature, etc., thereby expanding or laminating the laminate packaging material constituting the electrochemical element. The dimensions of the electrochemical element may fluctuate due to shrinkage. For this reason, improvement in the dimensional stability of the entire module during use of each electrochemical element is important in order to improve the safety of the entire module.

  Conventionally, as a countermeasure against expansion or contraction of a battery using a laminate exterior material that constitutes a module, for example, Patent Document 1 discloses a method in which a spacer is arranged between each battery to cope with a dimensional variation of each battery. Proposed.

Japanese Patent No. 4070798

  However, the method using the spacer described in Patent Document 1 has a problem that the module structure becomes complicated and the interval between the batteries becomes too large, and the volume energy efficiency of the entire module is lowered.

  The present invention solves the above problem, and provides an electrochemical element module that absorbs expansion or contraction of an electrochemical element with a simple structure and has high volumetric energy efficiency and safety.

  The electrochemical element module of the present invention is an electrochemical element module in which a plurality of electrochemical elements are stacked and accommodated in an exterior body, and between the adjacent electrochemical elements and the main surface of the electrochemical element And an inner surface of the exterior body, a thin film-like spacer having adhesiveness is disposed.

  ADVANTAGE OF THE INVENTION According to this invention, even if each electrochemical element expand | swells or shrinks | contracts, the dimension variation by it can be absorbed and the electrochemical element module with high volume energy efficiency and safety | security can be provided.

1A is a perspective view for explaining an electrode body used in the unit cell of Embodiment 1, FIG. 1B is a perspective view showing a state in which the electrode body is housed in an exterior material, and FIG. 1C is an electrode body. It is a perspective view of the state accommodated in the exterior material. It is a side view which shows the state which laminated | stacked the cell of Embodiment 1 and formed the battery laminated body. 3A to 3D are diagrams illustrating a process of producing a laminated tape by folding a single-sided adhesive tape in a double manner. It is a side view which shows the state which has arrange | positioned the plate-shaped body which comprises an exterior body to the upper and lower sides of a battery laminated body. It is a see-through | perspective perspective view which shows the state which formed the exterior body and completed the battery module of Embodiment 1. FIG. It is arrow sectional drawing of the II line | wire of FIG. It is sectional drawing of the electrochemical module of Embodiment 2. FIG. It is sectional drawing of the electrochemical module of Embodiment 3. It is sectional drawing of the electrochemical module of Embodiment 4.

  The electrochemical element module of the present invention includes a plurality of electrochemical elements stacked and accommodated in the exterior body, between the adjacent electrochemical elements, and the main surface of the electrochemical element and the inner surface of the exterior body. Between, a thin-film spacer having adhesiveness is arranged.

  By arranging the spacer, a gap is generated between the adjacent electrochemical elements and between the main surface of the electrochemical element and the inner surface of the exterior body, and when the electrochemical element expands in the gap. It can be used as a buffer area. For this reason, the expansion | swelling of an electrochemical element can be absorbed in this gap | interval, the dimensional stability as the whole module improves, and the safety | security of the whole module can be improved by extension.

  Further, since the spacer has adhesiveness, the positional stability of the electrochemical element in the module is improved, and as a result, the vibration resistance of the entire module is increased. Furthermore, since the spacer is in the form of a thin film, an excessive space is not required in the module, and the volume energy efficiency of the entire module is not significantly reduced.

  The thickness of the spacer is preferably 50 μm or more and 5 mm or less, and more preferably 100 μm or more and 3.5 mm or less. If the thickness of the spacer is less than 50 μm, the generated gap tends to be too small to function as a buffer region. On the other hand, if the thickness of the spacer exceeds 5 mm, the gap generated is too large to function as a buffer region, but the volume energy efficiency of the entire module tends to be reduced, and between the adjacent electrochemical elements. When a heat dissipating member described later is disposed, the heat dissipating efficiency tends to decrease.

  The electrochemical device includes an electrochemical device element, a flexible packaging material that houses the electrochemical device element, and an electrode lead terminal portion that is led out from the packaging material. The outer periphery is formed in a rectangular shape, and among the outer periphery of the exterior material, three sides other than the one side that is valley-folded are joined with a predetermined width to form a sealing portion, and the three sides of the sealing portion are The electrode lead terminal portion can be drawn from either side. In addition, two rectangular outer packaging materials are prepared without valley-folding the outer packaging material, the electrochemical element element is accommodated between the two outer packaging materials, and the four sides of the two outer packaging materials May be joined to form a sealing portion, and the electrode lead terminal portion may be drawn out from any one of the four sides of the sealing portion.

  When the electrochemical element is configured as described above, a gap is usually generated between the electrochemical element and the exterior body, but the gap is preferably filled with an expandable member. As a result, even if the electrochemical element contracts and further voids are generated between the adjacent electrochemical elements and between the main surface of the electrochemical element and the inner surface of the exterior body, the inflatable member remains in the gap. Can be prevented, the deterioration of the fixing accuracy of each electrochemical element can be prevented, and as a result, the safety of the entire module can be improved.

  The expandable member preferably includes a heat conductive material. Thereby, the heat dissipation of the whole module can be improved.

  Moreover, it is preferable to arrange | position a heat radiating member further between the said adjacent electrochemical elements, and it is preferable that the said heat radiating member consists of a sheet-like metal member. Thereby, the heat dissipation of the whole module can further be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in FIGS. 1-9, the same code | symbol is attached | subjected to the same part and the overlapping description may be abbreviate | omitted. In addition, in FIGS. 1 to 9, there are some parts that are represented at different ratios from the actual size of the members for easy understanding of the drawings.

(Embodiment 1)
First, an embodiment of an electrochemical element used in the electrochemical element module of the present invention will be described. The electrochemical element used in the present invention includes a primary battery, a secondary battery, an electric double layer capacitor (capacitor), and the like. In this embodiment, a flat lithium ion secondary battery (hereinafter referred to as a single battery) is used as the electrochemical element. A battery is sometimes described as an example. FIG. 1A is a perspective view for explaining an electrode body used in the unit cell of the present embodiment, FIG. 1B is a perspective view showing a state in which the electrode body is housed in an exterior material, and FIG. 1C shows an electrode body. It is a perspective view of the state accommodated in the exterior material.

  1A, an electrode body 10 included in a battery element (electrochemical element element) is produced by laminating a rectangular positive electrode 11 and a rectangular negative electrode 12 with a rectangular separator 13 interposed therebetween. A positive electrode lead terminal 11 a is provided at one end of the positive electrode 11, and a negative electrode lead terminal 12 a is provided at one end of the negative electrode 12.

  In FIG. 1B, a rectangular-shaped exterior material 14 having flexibility is formed by a first exterior surface 14a and a second exterior surface 14b which are valley-folded at a side 18. An electrode housing portion 15 is formed on the first exterior surface 14a by deep drawing. Each positive electrode lead terminal 11a (FIG. 1A) and each negative electrode lead terminal 12a (FIG. 1A) are overlapped and welded to form a positive electrode lead terminal portion 16a and a negative electrode lead terminal portion 16b, respectively.

  In FIG. 1C, the electrode body 10 is accommodated in a space portion (electrode accommodating portion 15) formed by the first exterior surface 14a and the second exterior surface 14b that are valley-folded together with the electrolytic solution. In addition, three sides of the outer periphery of the exterior material 14 other than the side 18 where the valleys are folded are joined with a predetermined width to form the sealing portions 17a, 17b, and 17c. The positive electrode lead terminal portion 16 a and the negative electrode lead terminal portion 16 b are drawn out from the sealing portion 17 c facing the valley-folded side 18 of the exterior material 14. In this way, the cell 20 is produced.

  The positive electrode 11 is obtained by applying a positive electrode mixture paste obtained by sufficiently adding a solvent to a mixture containing a positive electrode active material, a positive electrode conductive additive, a positive electrode binder, and the like on both surfaces of the positive electrode current collector. After drying, the positive electrode mixture layer can be formed by controlling to a predetermined thickness and a predetermined electrode density.

Examples of the positive electrode active material include lithium cobalt oxides such as LiCoO ₂ , lithium manganese oxides such as LiMn ₂ O ₄ , lithium nickel oxides such as LiNiO _2, etc., and can absorb and release lithium ions. If it is, it will not be limited to these.

  The positive electrode conductive additive may be added as necessary for the purpose of improving the conductivity of the positive electrode mixture layer. Examples of the conductive auxiliary include carbon black, ketjen black, acetylene black, and fibrous carbon. Carbon powder such as graphite and metal powder such as nickel powder can be used.

  Examples of the positive electrode binder include, but are not limited to, polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).

  As the solvent, for example, N-methyl-2-pyrrolidone or the like can be used.

  The positive electrode current collector is not particularly limited as long as it is an electron conductor that is substantially chemically stable in the battery. As the positive electrode current collector, for example, an aluminum foil having a thickness of 10 to 30 μm is used.

  Although the thickness of the positive electrode 11 is not specifically limited, Usually, it is 110-230 micrometers.

  The negative electrode 12 was prepared by applying a negative electrode mixture paste obtained by sufficiently adding a solvent to a mixture containing a negative electrode active material, a negative electrode conductive additive, a negative electrode binder, and the like on both surfaces of the negative electrode current collector. After drying, the negative electrode mixture layer can be formed by controlling to a predetermined thickness and a predetermined electrode density.

  Examples of the negative electrode active material include carbon materials such as natural graphite or artificial graphite such as massive graphite, flaky graphite, and earthy graphite, but are not limited thereto as long as lithium ions can be occluded / released. .

  About the said conductive additive for negative electrodes, the binder for negative electrodes, and a solvent, the thing similar to what was used for the positive electrode can be used.

  The negative electrode current collector is not particularly limited as long as it is an electron conductor that is substantially chemically stable in the constituted battery. As the negative electrode current collector, for example, a copper foil having a thickness of 5 to 20 μm is used.

  Although the thickness of the negative electrode 12 is not specifically limited, Usually, it is 65-220 micrometers.

  As the separator 13, an insulating microporous film having a large ion permeability and a predetermined mechanical strength is used. Moreover, what has the function to block | close a micropore and to raise resistance above a fixed temperature (100-140 degreeC) is preferable from the point of the safety | security improvement of a battery. Specifically, as the separator, a sheet, a nonwoven fabric, a woven fabric, or an olefin-based particle made of an olefin-based polymer or glass fiber such as polypropylene and polyethylene having organic solvent resistance and hydrophobicity is fixed with an adhesive. A porous body layer or the like is used.

  Although the thickness of the separator 13 is not specifically limited, Usually, it is 20-90 micrometers.

  As the exterior material 14, a laminate film or the like in which a thermoplastic resin layer is formed on both surfaces of a metal layer such as aluminum can be used. Thereby, sealing part 17a, 17b, 17c can be joined reliably by heat welding.

Examples of the electrolyte include vinylene carbonate (VC), propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (MEC). the organic solvents such as γ- butyrolactone to one or more kinds mixed solvent, for example, at least one of lithium selected from _{LiClO 4, LiPF 6, LiBF 4} , LiAsF 6, LiSbF 6, LiCF 3 SO 3 , etc. An electrolytic solution in which a salt is dissolved may be used. The concentration of Li ions in the electrolytic solution may be 0.5 to 1.5 mol / L.

  Next, an embodiment of the electrochemical element module of the present invention will be described. The electrochemical element module of the present invention is obtained by stacking a plurality of the above flat type lithium ion secondary batteries (unit cells) and storing them in the exterior body. Either single connection or parallel connection may be sufficient as the electrical connection of each cell.

  FIG. 2 is a side view of a state in which a battery stack is formed by stacking three unit cells of this embodiment, as viewed from the side 18 (FIGS. 1B and 1C) that is valley-folded. In FIG. 2, the unit cells 20 are stacked via a thin film-like spacer 21 having adhesiveness to form a battery stack 30. In FIG. 2, two spacers 21 are arranged in the width direction of the unit cells 20 between the adjacent unit cells 20, but the present invention is not limited to this. Since the spacer 21 has adhesiveness, the unit cells 20 can be fixed to each other.

  As the spacer 21, an adhesive tape in which an adhesive is applied to both surfaces of a film-like base material, an adhesive layer formed by applying an adhesive in a sheet shape, or the like can be used, but is not limited thereto.

  As said adhesive tape, the double-sided adhesive tape, the lamination | stacking tape etc. which folded the single-sided adhesive tape twice can be used, for example.

  3A to 3D show a process for producing a laminated tape by double folding a single-sided adhesive tape. First, as shown in FIG. 3A, a single-sided adhesive tape 19 is prepared. Next, as shown in FIGS. 3B and 3C, the single-sided adhesive tape 19 is deformed into a ring shape with the adhesive surface 19a facing outside, and both ends of the single-sided adhesive tape are fixed. Finally, as shown in FIG. 3D, the ring-shaped single-sided adhesive tape 19 is crushed to form a spacer 21 having adhesive surfaces 19a on both sides.

  Moreover, as the said double-sided adhesive tape and single-sided adhesive tape, various commercially available tapes can be used.

  As the adhesive when the adhesive layer is used for the spacer 21, for example, an organic adhesive such as synthetic rubber, epoxy, or cyanoacrylic can be used.

  As described above, the thickness of the spacer 21 may be 50 μm or more and 5 mm or less. The thickness of the spacer 21 may be adjusted by adjusting the thickness of the double-sided pressure-sensitive adhesive tape and single-sided pressure-sensitive adhesive tape to be used, the amount of pressure-sensitive adhesive applied to the tape, or the amount of adhesive.

  FIG. 4 is a side view showing a state in which the plate-like bodies 22 a and 22 b constituting the exterior body are arranged above and below the battery stack 30. In FIG. 4, the spacer 21 is also disposed between the plate-like bodies 22 a and 22 b and the unit cell 20. Thereby, the battery laminated body 30 and an exterior body can be firmly fixed.

  In FIG. 5, the plate-like bodies 22 c, 22 d, 22 e, and 22 f constituting the exterior body are further disposed on the side surface of the battery stack 30 (FIG. 4) to form the exterior body 40, and thus the battery module of the present embodiment. It is a see-through | perspective perspective view which shows the completed state. In FIG. 5, illustration of the battery laminated body accommodated in the inside is abbreviate | omitted in order to understand the structure of the exterior body 40 easily.

  The plate-like bodies 22a to 22f are preferably formed from a sheet-like metal member in order to improve the heat dissipation of the entire module. As the metal member, for example, aluminum or stainless steel can be used. The thickness of plate-like body 22a-22f is not specifically limited, For example, what is necessary is just to be 0.5-10 mm.

  The joining method of the plate-like bodies 22a to 22f is not particularly limited, and may be joined by welding, an adhesive tape, or the like, for example. Joining by welding is excellent in joining strength, and joining by an adhesive tape makes it easy to open the exterior body 40.

  6 is a cross-sectional view taken along the line II of FIG. However, in FIG. 6, only the plate-like bodies 22 a, 22 b, 22 c, and 22 d constituting the exterior body 40 are hatched to show a cross section. As shown in FIG. 6, a gap 23 and a gap 24 are formed by the spacer 21 between the adjacent unit cells 20 and between the unit cell 20 and the inner surface of the exterior body 40. The gap 23 and the gap 24 function as a buffer area when the unit cell 20 expands. However, since the expansion of the unit cell 20 usually occurs largely in the thickness direction, the gap 23 mainly functions as a buffer region when the unit cell 20 expands.

  In the present embodiment, although not shown, it is preferable that the gap 23 and the gap 24 are further filled with an inflatable member. Thereby, even if the cell 20 contracts and a space is generated, the expandable member can block the space, and a decrease in fixing accuracy of each cell 20 can be prevented. Further, even if the exterior material 14 (FIGS. 1B and 1C) of the unit cell 20 breaks due to some accident and the electrolytic solution or the like flows out, the outflow from the module can be prevented by the expandable member. Furthermore, the exterior body 40 often incorporates a protection circuit or the like that prevents malfunctions such as overcharging, and the inflatable member also has a function of preventing the adhesion of electrolyte etc. to the protection circuit or the like. Have. As the inflatable member, for example, a flexible pore member such as a spongy body, a fiber body, or a foam can be used, and these flexible pore members are filled in the gap 23 and the gap portion 24 in a pressurized state. Just keep it.

  The inflatable member is more preferably sticky. Thereby, the fall of the fixing precision of each cell 20 can be prevented further effectively. As the intumescent member having adhesiveness, the above sponge-like body, fiber body, foamed body and the like containing an adhesive component can be used.

  Furthermore, it is preferable that the said expansible member contains a heat conductive material. Thereby, the heat dissipation of the whole module can be improved. As the heat conductive material, for example, metal powder, metal fiber, or the like can be used.

(Embodiment 2)
Next, another embodiment of the electrochemical element module of the present invention will be described. FIG. 7 is a cross-sectional view of the electrochemical module of the present embodiment and corresponds to FIG. 6 of the first embodiment. Also in FIG. 7, only the plate-like bodies 22 a to 22 d constituting the exterior body 40 are hatched showing a cross section. The electrochemical element module according to the present embodiment has the same configuration as that of the electrochemical element module according to the first embodiment, except that the number of arrangement of the spacers 21 on the same surface is alternately two and one.・ Effects. Furthermore, in this embodiment, the number of the spacers 21 is smaller than that of the electrochemical element module of the first embodiment, so that the buffer region can be enlarged.

(Embodiment 3)
Next, still another embodiment of the electrochemical element module of the present invention will be described. FIG. 8 is a cross-sectional view of the electrochemical module of the present embodiment and corresponds to FIG. 6 of the first embodiment. Also in FIG. 8, only the plate-like bodies 22 a to 22 d constituting the exterior body 40 are hatched showing a cross section. The electrochemical element module of this embodiment is the same as that of Embodiment 1 except that the heat radiating plate 25 is arranged as a heat radiating member between adjacent unit cells 20 and the spacers 21 are also arranged on both surfaces of the heat radiating plate 25. The configuration is the same as that of the module, and the same operations and effects are achieved.

  In this embodiment, since the heat sink 25 is provided, the heat dissipation of the entire module can be improved. The heat radiating plate 25 can be formed of a metal plate such as aluminum, copper, nickel, iron, and stainless steel. As the heat radiating plate 25, one type of metal plate may be used, or two or more types of metal plates may be laminated and used. The thickness of the metal plate 25 varies depending on the size and thickness of the unit cell 20, and can be, for example, 200 μm or more and 10 mm or less, and more preferably 500 μm or less.

  Further, in the present embodiment, the expansion of the unit cell 20 can be suppressed by the heat radiating plate 25. Furthermore, in this embodiment, since the spacers 21 are arranged on both surfaces of the heat sink 25, the area of the gap 23 is larger than that of the electrochemical element module of the first embodiment, and the expansion of the unit cell 20 is more efficiently performed. Can be absorbed.

(Embodiment 4)
Next, still another embodiment of the electrochemical element module of the present invention will be described. FIG. 9 is a cross-sectional view of the electrochemical element module of the present embodiment, and corresponds to FIG. 6 of the first embodiment. Also in FIG. 9, only the plate-like bodies 22 a to 22 d constituting the exterior body 40 are hatched showing a cross section. The electrochemical element module according to the present embodiment has the same configuration as that of the electrochemical element module according to the third embodiment, except that the number of arrangement of the spacers 21 on the same surface is alternately two and one.・ Effects. Furthermore, in this embodiment, the number of the spacers 21 is smaller than that of the electrochemical element module of the third embodiment, so that the buffer region can be increased.

  The present invention can be implemented in other forms than the above without departing from the spirit of the present invention. The embodiments disclosed in the present application are merely examples, and the present invention is not limited thereto. The scope of the present invention is construed in preference to the description of the appended claims rather than the description of the above specification, and all modifications within the scope equivalent to the claims are construed in the scope of the claims. It is included.

  As described above, the present invention can provide an electrochemical element module that can absorb dimensional variations caused by expansion or contraction of the electrochemical element, and has high volumetric energy efficiency and safety. Therefore, the electrochemical device module of the present invention can be widely used as a power source for automobiles and motorcycles, a power source for moving bodies such as robots, etc., which are considered to be used in a severe environment.

DESCRIPTION OF SYMBOLS 10 Electrode body 11 Positive electrode 11a Positive electrode lead terminal 12 Negative electrode 12a Negative electrode lead terminal 13 Separator 14 Exterior material 14a 1st exterior surface 14b 2nd exterior surface 15 Electrode accommodating part 16a Positive electrode lead terminal part 16b Negative electrode lead terminal part 17a, 17b, 17c Sealing Stopping portion 18 Valley-folded side 19 Single-sided adhesive tape 19a Adhesive surface 20 Single cell 21 Spacers 22a, 22b, 22c, 22d, 22e, 22f Plate-like body 23 Gap 24 Gap portion 25 Heat sink 30 Battery stack 40 Outer body

Claims (7)

An electrochemical element module in which a plurality of electrochemical elements are stacked and housed inside an exterior body,
A thin film spacer having adhesiveness is disposed between the adjacent electrochemical elements and between the main surface of the electrochemical element and the inner surface of the exterior body. Element module.   The electrochemical element module according to claim 1, wherein the spacer has a thickness of 50 μm or more and 5 mm or less. The electrochemical device includes an electrochemical device element, a flexible packaging material that houses the electrochemical device element, and an electrode lead terminal portion that is led out from the packaging material.
The outer periphery of the exterior material is formed in a rectangular shape,
Of the outer periphery of the exterior material, three sides other than one side folded in the valley are joined with a predetermined width to form a sealing portion,
The electrochemical element module according to claim 1 or 2, wherein the electrode lead terminal portion is drawn out from any one of the three sides.   The electrochemical element module according to any one of claims 1 to 3, wherein a space between the electrochemical element and the exterior body is filled with an expandable member.   The electrochemical element module according to claim 4, wherein the expandable member includes a heat conductive material.   The electrochemical element module of any one of Claims 1-5 by which the heat radiating member is further arrange | positioned between the said adjacent electrochemical elements.   The electrochemical element module according to claim 6, wherein the heat dissipation member is made of a sheet-like metal member.

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