JP4483489B2 - Assembled battery - Google Patents

Description

  The present invention relates to an assembled battery. Specifically, the present invention relates to an improvement in a form in which individual cells constituting an assembled battery are connected.

  In recent years, in order to cope with air pollution and global warming, reduction of the amount of carbon dioxide has been strongly desired. In the automobile industry, the introduction of electric vehicles (EV) and hybrid electric vehicles (HEV) is expected to reduce carbon dioxide emissions, and motor-driven batteries that hold the key to commercialization are actively developed. ing.

As a battery for driving a motor, the use of a secondary battery that can be repeatedly charged has been proposed, and in particular, a sheet battery useful for weight reduction and miniaturization has attracted attention (for example, Patent Documents). 1).
Japanese Patent Laying-Open No. 2004-179053 (page 14, FIG. 8)

  Here, only one battery described in Patent Document 1 has a relatively small output (voltage) due to its structure. For this reason, a method of connecting a plurality of sheet-like batteries (unit cells) having a relatively small output (voltage) in series to form an assembled battery having a relatively large output (voltage) is conceivable.

  In the sheet-like battery described in Patent Document 1, the positive electrode terminal and the negative electrode terminal are respectively derived from the opposing short sides of the battery. When sheet batteries having such a structure are connected in series using a bus bar, current flowing from the negative terminal side of the sheet battery during discharge flows through the current collector over almost the entire length before flowing out from the positive terminal side. There is a need. For this reason, the internal resistance in the current collector is relatively large, and the generation of heat during battery use and the accompanying deterioration of battery elements are problematic. In order to reduce the internal resistance of the entire assembled battery, it is effective to reduce the internal resistance of the current collector. Moreover, since the cross-sectional area of the electrode terminal is relatively small, there is still room for reducing the internal resistance in the terminal portion.

  Then, an object of this invention is to provide the means which can reduce the internal resistance of the whole assembled battery by further reducing the internal resistance in the collector or electrode terminal of a cell.

The present invention is an assembled battery in which a plurality of sheet-like batteries in which a battery element that is substantially similar to the exterior is sealed inside a substantially rectangular exterior are connected in series, and the battery element The connected positive electrode terminal is derived from one side of the exterior, the negative electrode terminal connected to the battery element is derived from the other side of the exterior, and one sheet-like battery and another sheet adjacent thereto An assembled battery module in which two batteries are combined, in which a battery is connected by joining a positive electrode terminal of the one sheet battery and a negative electrode terminal of the other sheet battery, The assembled battery is assembled in a direction in which the convex portions of the respective assembled batteries face each other, and the convex portion of one assembled battery of the two assembled batteries is fitted with the concave portion of the other assembled battery. It is a module .

  In the assembled battery of the present invention, the internal resistance of the current collector and electrode terminals of the single cells constituting the assembled battery can be further reduced. Thereby, the internal resistance of the whole assembled battery can be reduced effectively.

  Moreover, the assembled battery module of this invention can contribute effectively to the improvement of the volume energy density of a battery.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention should be determined based on the description of the scope of claims, and is not limited to the following embodiments. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios. Further, in the present specification, “sheet-shaped battery”, “assembled battery”, “assembled battery module”, and “composite assembled battery module” are respectively defined as follows. “Sheet-shaped battery” refers to one battery in which battery elements are sealed with a flexible exterior. The “assembled battery” refers to a battery in which a plurality of sheet batteries are electrically connected. The “assembled battery module” refers to a battery formed by combining a plurality of assembled batteries. “Composite assembled battery module” refers to a battery formed by combining a plurality of assembled battery modules. Here, not only “sheet-shaped battery” but also “assembled battery”, “assembled battery module” and “composite assembled battery module” can be used as batteries. In this specification, the names of “sheet-like battery”, “assembled battery”, “assembled battery module”, and “composite assembled battery module” are used to facilitate understanding of the difference in battery size.

(First embodiment)
A first aspect of the present invention is an assembled battery in which a plurality of sheet-like batteries in which a battery element that is substantially similar to the exterior is sealed inside a substantially rectangular exterior are connected in series, A positive electrode terminal connected to the battery element is derived from one long side of the exterior, and a negative electrode terminal connected to the battery element is derived from the other long side of the exterior, adjacent to the one sheet-like battery The other sheet-like battery is an assembled battery in which the positive electrode terminal of the one sheet-like battery and the negative electrode terminal of the other sheet-like battery are connected to each other.

  Hereinafter, the configuration of the sheet battery constituting the assembled battery of the present embodiment (first embodiment) will be described, and then the configuration of the assembled battery of the present embodiment will be described.

  First, the structure of the sheet battery which comprises the assembled battery of this embodiment (1st Embodiment) is demonstrated easily.

  The sheet battery constituting the assembled battery of the present embodiment is not particularly limited, and examples thereof include nonaqueous electrolyte secondary batteries such as lithium ion secondary batteries, nickel-hydrogen secondary batteries, nickel-cadmium secondary batteries. Can be mentioned. Of these, lithium ion secondary batteries excellent in output and energy density are preferably used in consideration of use as a power source for vehicles. When 100 batteries are connected in series to form an assembled battery, the total output voltage of a nickel-hydrogen secondary battery is only about 120V, whereas 100 lithium ion secondary batteries are connected in series. When a battery is used, an assembled battery having an overall output voltage of about 360 V can be configured. In particular, from the viewpoint of obtaining high output, the lithium ion secondary battery as the sheet-like battery is preferably a bipolar lithium ion secondary battery (hereinafter also referred to as “bipolar battery”). Therefore, hereinafter, the case where the sheet battery constituting the assembled battery of the present invention is a bipolar battery will be described as an example. However, it goes without saying that the form of the sheet battery in the present invention is not limited to the bipolar battery.

  FIG. 1 is a schematic plan view of a sheet-like battery (bipolar battery) 20 constituting the assembled battery of this embodiment (first embodiment), and FIG. 2 is a sheet taken along line 2-2 shown in FIG. 1 is a schematic cross-sectional view of a battery (bipolar battery) 20.

  As shown in FIG. 1, each sheet-like battery (bipolar battery) 20 constituting the assembled battery of this embodiment is a battery element that is actually composed of a positive electrode, a negative electrode, an electrolyte layer (separator), and the like, and in which a charge / discharge reaction proceeds. 21 has a structure sealed inside a laminate sheet 29 which is an exterior. Here, the laminate sheet 29 and the battery element 21 are both rectangular and substantially similar.

  As shown in FIG. 2, a sheet-like battery (bipolar battery) 20 includes a plurality of bipolar devices in which a positive electrode active material layer 13 is formed on one surface of a current collector 11 and a negative electrode active material layer 15 is formed on the other surface. It has an electrode. Each bipolar electrode is laminated via an electrolyte layer 17 to form a battery element 21. At this time, each bipolar electrode and electrolyte layer are arranged such that the positive electrode active material layer 13 of one bipolar electrode and the negative electrode active material layer 15 of another bipolar electrode adjacent to the one bipolar electrode face each other through the electrolyte layer 17. 17 are stacked.

  The adjacent positive electrode active material layer 13, electrolyte layer 17, and negative electrode active material layer 15 constitute one unit cell layer 33. Therefore, it can be said that the battery element 21 has a configuration in which the single battery layer 33 is laminated via the current collector 11. And the insulating layer 35 is provided so that the cell layer 33 may be surrounded, and the short circuit between the adjacent electrical power collectors 11 is prevented. The number of stacked single battery layers 33 can be determined according to desired battery characteristics of the sheet-like battery (bipolar battery) 20. The size of the sheet-like battery (bipolar battery) 20 can also be determined according to the desired battery characteristics and installation environment of the sheet-like battery (bipolar battery) 20.

  Note that the current collector (outermost layer current collector) located in the outermost layer of the battery element 21 has a positive electrode active material layer 13 (positive electrode side outermost current collector 11a) or a negative electrode active material layer 15 ( Either one of the negative electrode side outermost layer current collectors 11b) is formed. Further, in FIG. 2, the negative electrode side outermost layer current collector 11b is arranged upward (upward in FIG. 2), and the positive electrode side outermost layer current collector 11a is arranged downward (downward in FIG. 2). Of course, these may be arranged in reverse.

  In the sheet-like battery (bipolar battery) 20 shown in FIGS. 1 and 2, the positive electrode side outermost layer current collector 11a is extended in the X positive direction in the drawing, and one long side of the laminate sheet 29 (shown in FIG. 1). Side BC) is derived as a positive electrode terminal 25. On the other hand, the negative electrode side outer layer current collector 11b is extended in the negative X direction in the figure, and from the other long side of the laminate sheet 29 (side opposite to the side from which the positive electrode terminal 25 is led; side DA shown in FIG. 1). Derived as a negative electrode terminal 27. Accordingly, in the sheet-like battery (bipolar battery) 20 shown in FIGS. 1 and 2, the widths of the positive electrode terminal 25 and the negative electrode terminal 27 connected to the battery element 21 are the same as the length of the battery element 21 in the longitudinal direction.

  Then, the structure of the assembled battery of this embodiment is demonstrated.

  FIG. 3 is a partial plan view showing a part of the assembled battery of the present embodiment (first embodiment). FIG. 4 is a cross-sectional view taken along line 4-4 shown in FIG. In FIG. 4, battery elements 21 other than the outermost layer current collectors (11a, 11b) and the electrode terminals (25, 27) are shown as rectangles for convenience of explanation.

  In the assembled battery 10 shown in FIGS. 3 and 4, the individual cells (sheet-like battery 20) constituting the assembled battery 10 are connected in series in the planar direction. 3 and 4, only a part of the sheet batteries (20a, 20b, 20c) constituting the assembled battery 10 are shown for convenience of explanation. However, the number of sheet-like batteries 20 constituting the assembled battery 10 of the present invention is not particularly limited, and can be appropriately determined in consideration of a desired output of the assembled battery 10 and the like.

  In the assembled battery 10 of this embodiment, the positive electrode terminal 25 derived from one sheet-like battery 20 (for example, 20a shown in FIG. 3) constituting the assembled battery 10 and the one sheet-like battery 20 (20a) are adjacent to each other. The negative electrode terminal 27 derived from the other sheet-like battery 20 (for example, 20b shown in FIG. 3) is directly joined. Thereby, the one sheet-like battery 20 (20a) and the other sheet-like battery 20 (20b) are connected in series. At this time, the positive electrode terminal 25 and the negative electrode terminal 27 are joined by ultrasonic welding. However, depending on the case, joining may be performed by other methods described later.

  As described above, the assembled battery 10 of the present embodiment is configured by connecting the sheet batteries 20 in series. Therefore, when the battery pack 10 is discharged, a current flows in the direction of “negative electrode terminal 27 → positive electrode terminal 25” in the sheet battery 20. Further, at the time of discharging, a current flows in the direction of “a positive terminal 25 of one battery → a negative terminal 27 of another battery” in the connection part of the two sheet batteries 20.

  Therefore, in the assembled battery 10 of the present embodiment, the positive terminal 25 derived from the sheet battery 20 connected to the end is not connected to the negative terminal 27 of the other sheet batteries 20 constituting the assembled battery 10. It is used as the positive terminal of the assembled battery 10 as a whole. Similarly, the negative electrode terminal 27 derived from the sheet battery 20 connected to the end is not connected to the positive electrode terminal 25 of the other sheet battery 20 constituting the assembled battery 10, and the negative electrode terminal of the assembled battery 10 as a whole. Used as

  According to the assembled battery 10 of the present embodiment (first embodiment), the electrode terminals (25, 27) of the individual sheet batteries 20 are led out from the long sides of the laminate sheet 29. For this reason, the distance which flows through the electrical power collector 11 before the electric current which flowed into the battery element 21 from the negative electrode terminal 27 at the time of discharge flows out from the positive electrode terminal 25 is shortened. Therefore, the internal resistance due to the current flowing through the current collector 11 can be reduced. Moreover, according to the assembled battery 10 of this embodiment (1st Embodiment), the cross-sectional area of an electrode terminal (25, 27) can also be increased, and the inside by an electric current flowing through an electrode terminal (25, 27). Resistance can also be reduced. As a result, the output of the assembled battery 10 can be improved. Moreover, the generation of heat due to the internal resistance is suppressed, and deterioration of the battery element 21 due to this heat can be prevented. Furthermore, according to the assembled battery 10 of the present embodiment (first embodiment), the adjacent sheet batteries 20 are connected by directly joining the electrode terminals (25, 27). For this reason, it is not necessary to interpose a bus bar etc. between electrode terminals. As a result, there is an advantage that problems such as an increase in internal resistance and a decrease in volume efficiency due to the installation of the bus bar do not occur.

  In the assembled battery 10 of the present embodiment shown in FIGS. 3 and 4, the ratio of the length in the longitudinal direction of the battery element 21 to the length in the width direction of the battery element 21 of each sheet battery 20 constituting the assembled battery 10. The aspect ratio defined as is 3.0. That is, in the form shown in FIGS. 3 and 4, the length in the longitudinal direction of the battery element 21 of the sheet battery 20 is three times the length in the width direction of the battery element 21. However, it is not limited only to the form in which the aspect ratio is 3.0. According to the configuration of the present invention, the aspect ratio is necessarily larger than 1, but the aspect ratio is preferably 2.0 or more, and more preferably 3.0 or more. When the aspect ratio is a value within such a range, the effect of the assembled battery 10 of the present embodiment described above can be further exhibited. However, if the aspect ratio is too large, the area and mass of the electrode terminal increase, and the performance of the entire battery may be degraded. From such a viewpoint, the aspect ratio is preferably 100 or less, and more preferably 20 or less.

  Hereinafter, for reference, members constituting the sheet battery (bipolar battery) 20 will be described, but the present invention is not limited to the following modes.

[Current collector]
The current collector 11 is made of a conductive material such as an aluminum foil, a copper foil, or a stainless steel (SUS) foil. The general thickness of the current collector 11 is 1 to 30 μm. However, the current collector 11 having a thickness outside this range may be used. The size of the current collector 11 is determined according to the use application of the bipolar battery 20. If a large electrode used for a large battery is manufactured, the current collector 11 having a large area is used. If a small electrode is manufactured, the current collector 11 having a small area is used.

[Active material layer]
The positive electrode active material layer 13 includes a positive electrode active material. As the positive electrode active material, a lithium-transition metal composite oxide is preferable, and examples thereof include a Li—Mn composite oxide such as LiMn ₂ O ₄ and a Li—Ni composite oxide such as LiNiO ₂ . In some cases, two or more positive electrode active materials may be used in combination.

  The negative electrode active material layer 15 includes a negative electrode active material. As the negative electrode active material, the above lithium transition metal-composite oxide or carbon is preferable. Examples of carbon include graphite-based carbon materials such as natural graphite and artificial graphite, carbon black, activated carbon, carbon fiber, coke, soft carbon, and hard carbon.

  The positive electrode active material layer 13 and the negative electrode active material layer 15 may contain other materials if necessary. For example, a binder, a conductive additive, a lithium salt (supporting electrolyte), an ion conductive polymer, and the like can be included. When an ion conductive polymer is included, a polymerization initiator for polymerizing the polymer may be included.

  Examples of the binder include polyvinylidene fluoride (PVdF) and a synthetic rubber binder.

  The conductive assistant refers to an additive that is blended in order to improve the conductivity of the positive electrode active material layer 13 or the negative electrode active material layer 15. Examples of the conductive aid include carbon powder such as graphite.

As a lithium salt (supporting electrolyte), LiBETI (lithium bis (perfluoroethylenesulfonylimide); Li (C ₂ F ₅ SO ₂ ) ₂ N), LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ Etc.

  Examples of the ion conductive polymer include polyethylene oxide (PEO) -based and polypropylene oxide (PPO) -based polymers. Here, the ion conductive polymer may be the same as or different from the ion conductive polymer used as the electrolyte in the electrolyte layer 17 of the bipolar battery 20, but is preferably the same.

  The polymerization initiator is added to act on the crosslinkable group of the ion conductive polymer to advance the crosslinking reaction. Depending on the external factor for acting as an initiator, it is classified into a photopolymerization initiator, a thermal polymerization initiator and the like. Examples of the polymerization initiator include azobisisobutyronitrile (AIBN), which is a thermal polymerization initiator, and benzyl dimethyl ketal (BDK), which is a photopolymerization initiator.

  The compounding ratio of the components contained in the positive electrode active material layer 13 and the negative electrode active material layer 15 is not particularly limited. The blending ratio can be adjusted by appropriately referring to known knowledge about lithium ion secondary batteries.

[Electrolyte layer]
In general, the electrolyte constituting the electrolyte layer 17 includes a liquid electrolyte or a polymer electrolyte. In the present invention, a polymer electrolyte is preferably used. By using the polymer electrolyte, leakage of electrolyte and the like can be prevented, and the safety of the bipolar battery 20 can be improved.

  The polymer electrolyte is composed of an ion conductive polymer, and the material is not limited as long as it exhibits ion conductivity. Made by forming a cross-linked structure by polymerizing a polymerizable polymer for forming a polymer electrolyte by thermal polymerization, ultraviolet polymerization, radiation polymerization, or electron beam polymerization because it can exhibit excellent mechanical strength. Are preferably used. In the electrolyte layer formed of such a polymer electrolyte, liquid leakage does not occur, so that the reliability of the battery is improved and the bipolar battery 20 having a simple configuration and excellent output characteristics is formed.

  Examples of the polymer electrolyte include all solid polymer electrolytes and polymer gel electrolytes.

The all solid polymer electrolyte is not particularly limited, and examples thereof include polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof. Lithium salts such as LiBETI, LiBF ₄ , LiPF ₆ , LiN (SO ₂ CF ₃ ) ₂ , and LiN (SO ₂ C ₂ F ₅ ) ₂ can be well dissolved in such polyalkylene oxide polymers. In addition, these polymers can exhibit excellent mechanical strength by forming a crosslinked structure. In the present invention, it is preferable that the all solid polymer electrolyte is contained in both the positive electrode active material layer 13 and the negative electrode active material layer 15 in order to further improve the electrode characteristics.

  The polymer gel electrolyte generally refers to an electrolyte solution held in an all-solid polymer electrolyte having ion conductivity. However, in the present application, a polymer electrolyte having a similar electrolyte solution held in a polymer skeleton having no lithium ion conductivity is also included in the polymer gel electrolyte. The type of the nonaqueous electrolytic solution (electrolyte salt and plasticizer) used is not particularly limited.

  When the electrolyte layer is made of a polymer gel electrolyte, the electrolyte layer is formed by impregnating a separator such as a nonwoven fabric with a polymer gel raw material solution and then polymerizing using the above-described various methods. It may be. By using the separator, the filling amount of the electrolytic solution can be increased, and the thermal conductivity inside the battery is ensured.

[Insulation layer]
In the bipolar battery 20, an insulating layer 35 is usually provided around each single battery 33. This insulating layer 35 is provided for the purpose of preventing short-circuiting due to slight unevenness of the ends of the unit cells 33 in the battery element 21 due to contact between adjacent current collectors 11 in the battery. By installing such an insulating layer 35, long-term reliability and safety are ensured, and a high-quality bipolar battery 20 can be provided.

  The insulating layer 35 only needs to have insulating properties, sealing properties against falling off of the solid electrolyte, sealing properties against moisture permeation from the outside (sealing properties), heat resistance under battery operating temperature, etc. Urethane resin, epoxy resin, polyethylene resin, polypropylene resin, polyimide resin, rubber and the like can be used. Of these, urethane resins and epoxy resins are preferred from the viewpoints of corrosion resistance, chemical resistance, ease of production (film forming properties), economy, and the like.

[Electrode terminal]
In the bipolar battery 20, the electrode terminals (the positive terminal 25 and the negative terminal 27) are connected to the outermost layer current collector (11 a, 11 b) for the purpose of extracting current outside the battery. Specifically, the positive electrode terminal 25 is connected to the positive electrode outermost layer current collector 11a, and the negative electrode terminal 27 is connected to the negative electrode outermost layer current collector 11b.

  The material of the electrode terminals (the positive electrode terminal 25 and the negative electrode terminal 27) is not particularly limited, and a known material conventionally used as an electrode terminal of a bipolar battery can be used. Examples thereof include aluminum, copper, titanium, nickel, stainless steel (SUS), and alloys thereof. The positive electrode terminal 25 and the negative electrode terminal 27 may be made of the same material or different materials. Moreover, as shown in FIG. 3, it is good also as an electrode terminal (25, 27) by extending outermost layer collector (11a, 11b), or connecting the electrode terminal prepared separately to outermost layer collector. May be.

[Exterior]
In the bipolar battery 20, the battery element 21 is sealed in an exterior such as a laminate sheet 29 in order to prevent external impact and environmental degradation during use. The exterior is not particularly limited, and a conventionally known exterior can be used. A polymer-metal composite laminate sheet or the like excellent in thermal conductivity can be preferably used in that heat can be efficiently transferred from a heat source of an automobile and the inside of the battery can be rapidly heated to the battery operating temperature.

  As described above, the case where the sheet battery 20 constituting the assembled battery 10 of the present embodiment is a bipolar battery has been described in detail. However, the present invention is not limited to such a form. For example, a lithium ion secondary battery that is not a bipolar battery ( A general lithium ion secondary battery) may be used as the sheet battery 20 constituting the assembled battery 10.

  Then, the manufacturing method of the assembled battery 10 of this embodiment is demonstrated easily.

  First, the sheet battery 20 is prepared. The specific form of the sheet-like battery 20 is not particularly limited. For example, when a bipolar lithium ion secondary battery is used as the sheet-like battery 20, the sheet-like battery 20 may be made of the above-described materials. When other batteries are used as the sheet-like battery 20, conventionally known knowledge about the battery can be referred to as appropriate.

  Next, the positive electrode terminal 25 and the negative electrode terminal 27 of the sheet battery 20 connected adjacently are joined. Thereby, each sheet-like battery 20 is electrically connected, and the assembled battery 10 is completed.

  There is no particular limitation on the joining method. For example, a method of crimping two members to be connected or a method of bonding using a conductive adhesive may be used. Moreover, you may connect by a rivet, caulking, etc. However, from the viewpoint of further reducing the resistance at the connection portion, connection by welding can be preferably employed. When connecting by welding, ultrasonic welding, resistance welding, laser welding or the like is used, and ultrasonic welding can be used more preferably from the viewpoint of ease of joining, joining speed, cost of the apparatus, and the like.

(Second Embodiment)
The 2nd of this invention is related with the assembled battery module formed by combining the assembled battery of said 1st Embodiment. In addition, detailed description is abbreviate | omitted about the structure similar to said 1st Embodiment about each assembled battery or each sheet-like battery which comprises the assembled battery module of this embodiment (2nd Embodiment). Moreover, the same reference numerals are assigned to the same members as those in the first embodiment.

  FIG. 5 is a partial cross-sectional view showing a part of the assembled battery module of the present embodiment (second embodiment). The assembled battery module 40 shown in FIG. 5 is configured by combining two assembled batteries (10a, 10b) of the first embodiment. However, for convenience of explanation, only a part of the sheet battery 20 constituting each assembled battery 10 of the assembled battery module 40 of the present embodiment is shown. It is the same as that of said 1st Embodiment that the number of the sheet-like batteries 20 which comprise each assembled battery is not restrict | limited in particular.

  In the assembled battery module 40 of the present embodiment (second embodiment), the two assembled batteries (10a, 10b) constituting the assembled battery module 40 have the convex portions of the assembled batteries (10a, 10b) face each other. Combined in the direction. At this time, the convex portion of one assembled battery 10 is fitted with the concave portion of the other assembled battery 10. Specifically, the convex part of the assembled battery 10a is fitted with the concave part of the assembled battery 10b. Similarly, the convex part of the assembled battery 10b is fitted with the concave part of the assembled battery 10a. In the present application, the “convex portion” means a portion (42 in FIG. 4) where the exterior protrudes when the battery element 21 is sealed inside the exterior such as the laminate sheet 29. On the other hand, the “concave portion” means a concave portion (44 in FIG. 4) between the convex portion and the convex portion, which is generated with the formation of the convex portion. Moreover, the fitted convex part and recessed part may be adhere | attached, and may not be adhere | attached.

  The assembled battery module 40 of this embodiment (2nd Embodiment) is comprised by combining the assembled battery 10 of said 1st Embodiment. Therefore, the assembled battery module 40 of the present embodiment (second embodiment) can exhibit the same functions and effects as described for the assembled battery 10 of the first embodiment.

  Furthermore, the assembled battery module 40 of this embodiment (2nd Embodiment) has the structure by which the convex part and recessed part of the two assembled batteries 10 were fitted. For this reason, it is extremely excellent in space efficiency. Therefore, the assembled battery module 40 of this embodiment (second embodiment) can effectively contribute to the improvement of the volume energy efficiency of the assembled battery 10.

  In FIG. 5, the electrical connection form between the two assembled batteries 10 constituting the assembled battery module 40 is not shown. However, the assembled batteries 10 constituting the assembled battery module 40 of this embodiment (second embodiment) may or may not be electrically connected. Moreover, when the assembled batteries 10 which comprise the assembled battery module 40 are electrically connected, you may connect in series and may be connected in parallel. Furthermore, the direction of the current flowing through each assembled battery 10 to be combined is not particularly limited, and the two assembled batteries 10 to be combined may flow in the same direction or in the opposite direction.

  The form shown in FIG. 5 is a close-packed structure. In other words, in the form shown in FIG. 5, the two assembled batteries 10 constituting the assembled battery module 40 are combined by closely fitting the convex portions and the concave portions. However, it is not limited only to such a form. For example, as shown in FIG. 6, a configuration in which two assembled batteries 10 constituting the assembled battery module 40 are combined so as to form a gap 46 in a fitting portion between a convex portion and a concave portion can also be adopted. . In the form shown in FIG. 6, the gap 46 formed in the fitting portion between the convex portion of one assembled battery 10 and the concave portion of another assembled battery 10 constituting the assembled battery module 40 is an assembled battery module that generates heat by energization. It can function as a cooling means for cooling 40. Therefore, according to such a form, deterioration of the battery element 21 due to heat generation by energization can be suppressed.

The size of the gap 46 is not particularly limited, and may be appropriately determined in consideration of desired battery performance, cooling performance by the gap 46, the volume of the assembled battery module 40, and the like. However, in the cross section of the assembled battery module perpendicular to the long side of the exterior of the sheet-shaped battery as shown in FIG. 6, the cross-sectional area of the gap 46 formed in the fitting portion between the convex portion and the concave portion (the hatched line in FIG. 6) the sum of the parts S ₁ and the hatched portion S ₂₎ is preferably less than the cross-sectional area of the convex portion 42 is fitted to the fitting portion. If the cross-sectional area of the gap 46 exceeds the cross-sectional area of the convex portion 42, the volume energy density of the assembled battery module 40 may be reduced. The size of the gap 46 can be controlled by adjusting the size of the battery element 21 or the length of the electrode terminals (25, 27). Further, a cooling medium (for example, a cooling gas) for cooling the assembled battery module 40 may be circulated in the gap 46 as necessary. Thereby, the cooling performance by installation of the space | gap 46 can improve.

(Third embodiment)
The third embodiment relates to a composite battery module obtained by stacking the battery modules 40 of the second embodiment. In addition, about each assembled battery module, each assembled battery, or each sheet-shaped battery which comprises the composite assembled battery module of this embodiment (3rd Embodiment), said 1st Embodiment and 2nd Embodiment Detailed description of the same configuration is omitted. The same members as those in the first embodiment and the second embodiment are denoted by the same reference numerals.

  FIG. 7 is a partial cross-sectional view showing a part of the composite battery module of the present embodiment (third embodiment). The composite assembled battery module 50 shown in FIG. 7 is configured by stacking four assembled battery modules 40 of the second embodiment shown in FIG. For convenience of explanation, only a part of the sheet-like battery 20 that is a component of the four assembled battery modules is shown. The number of sheet batteries 20 constituting each assembled battery or each assembled battery module is not particularly limited, as in the first and second embodiments. Furthermore, the number of stacked battery modules 40 constituting the composite battery module 50 is not particularly limited, and can be determined as appropriate in consideration of desired battery characteristics and battery volume.

  Also by the composite battery module 50 of the present embodiment (third embodiment), the same effects as described above for the battery pack 10 of the first embodiment and the battery module 40 of the second embodiment can be obtained. .

  In addition, each assembled battery module 40 which comprises the composite battery module 50, or each assembled battery 10 which comprises each assembled battery module 40 may each be electrically connected, and does not need to be connected. . For specific forms of electrical connection, conventionally known knowledge can be referred to as appropriate. Each assembled battery module 40 may have the gap 46 described with reference to FIG. 6 in the second embodiment.

  The composite battery module 50 of the present embodiment (third embodiment) may have the form shown in FIG. In the form shown in FIG. 8, the heat sink 60 is interposed between the assembled battery modules 40 stacked adjacent to each other. Of course, the composite battery module 50 of the form shown in FIG. 8 can also achieve the same effects as those described above for the first and second embodiments. However, when the heat sink 60 is interposed between the assembled battery modules 40, still other effects can be obtained. That is, according to such a form, the heat generated from the battery element as the composite battery pack 40 is energized can be dissipated into the outside air through the heat dissipation plate 60. As a result, the heat resistance of the composite battery module 50 can be improved. The assembled battery module 40 and the heat radiating plate 60 constituting the composite assembled battery module 50 may be bonded or may not be bonded.

  The material which comprises the heat sink 60 is not restrict | limited in particular. From the viewpoint of excellent heat dissipation, it is preferable that the heat dissipation plate 60 be made of a material having high thermal conductivity. Further, from the viewpoint of preventing a short circuit between the joint portions of the electrode terminals, it is preferable that the heat radiating plate 60 is made of an insulating material or a material whose surface is insulated. Examples of the material having such characteristics include anodized aluminum and tantalum, but are not limited to these materials. For example, the heat dissipation plate 60 may be made of a metal material whose surface is coated with a resin.

(Fourth embodiment)
The fourth embodiment relates to a configuration that can further improve the heat resistance of the composite battery module. The composite battery module 50 of the fourth embodiment is different from the composite battery module 50 of the third embodiment in the form of the battery module 40 constituting the composite battery module 50. Note that detailed description of the same configuration as that of the third embodiment is omitted. The same members as those in the third embodiment are denoted by the same reference numerals.

  FIG. 9 is a partial cross-sectional view showing a part of the composite battery module 50 of the present embodiment (fourth embodiment).

  The assembled battery module 40 constituting the composite assembled battery module 50 of the present embodiment (fourth embodiment) is composed of two sets constituting the assembled battery module 40 in the same manner as the assembled battery module 40 of the second embodiment. The batteries (10a, 10b) are combined in the direction in which the convex portions of the respective assembled batteries (10a, 10b) face each other. However, unlike the assembled battery module 40 of the second embodiment, the two assembled batteries (10a, 10b) are combined so that the convex portions of the assembled batteries (10a, 10b) overlap each other. For this reason, a gap 46 larger than the form shown in FIG. 6 is formed between the two assembled batteries (10a, 10b) combined. Note that the overlapping convex portions may be bonded or may not be bonded.

  In the composite assembled battery module 50 of the present embodiment (fourth embodiment), four assembled battery modules 40 having the above-described configuration are stacked via a heat sink 60. Therefore, the heat generated from the battery element with energization can be dissipated into the outside air through both the gap 46 and the heat radiating plate 60. As a result, the composite battery module 50 having extremely excellent heat resistance can be provided. Note that a cooling medium such as a cooling gas may be circulated in the gap 46 as in the second embodiment. Moreover, the specific structure of the heat sink 60 is the same as that of said 3rd Embodiment.

(Fifth embodiment)
In the fifth embodiment, the assembled battery 10 according to the first embodiment, the assembled battery module 40 according to the second embodiment, and the composite assembled battery module 50 according to the third or fourth embodiment are mounted as a power source for driving the motor. Configure the equipment. At this time, only one of the assembled battery 10, the assembled battery module 40, and the composite assembled battery module 50 may be mounted, or may be mounted by combining two or more.

  For reference, FIG. 10 shows a schematic diagram of an automobile 100 equipped with the composite battery module 50 of the third embodiment. The composite battery module 50 mounted on the automobile has the effects as described above. Therefore, the transport device of this embodiment, particularly the automobile, can exhibit excellent performance particularly in terms of output and space efficiency. In some cases, the assembled battery module 40 or the composite assembled battery module 50 with improved heat resistance can be mounted. In such a case, the durability of a transport device, particularly an automobile, can be improved.

  Examples of transportation equipment on which the assembled battery 10, the assembled battery module 40, or the composite assembled battery module 50 of the present invention can be mounted include trains, two-wheeled vehicles, ships, and airplanes in addition to automobiles. However, the present invention is not limited to these configurations, and any transport device that obtains power by driving a motor can be used as the transport device of the present embodiment. In addition, examples of the automobile according to the present embodiment include an electric car, a hybrid electric car, and a fuel cell car.

  The preferred embodiments of the present invention have been described above. However, the technical scope of the present invention is not limited to the embodiments described above, and various modifications, omissions, and additions can be made by those skilled in the art. It is.

It is a schematic plan view of the sheet-like battery (bipolar battery) 20 which comprises the assembled battery of 1st Embodiment. It is a schematic cross section of the sheet-like battery (bipolar battery) 20 along line 2-2 shown in FIG. It is a fragmentary top view which shows a part of assembled battery of 1st Embodiment. FIG. 4 is a cross-sectional view taken along line 4-4 shown in FIG. It is a fragmentary sectional view which shows a part of assembled battery module of 2nd Embodiment. It is a fragmentary sectional view showing a part of modification of an assembled battery module of a 2nd embodiment. It is a fragmentary sectional view which shows a part of composite battery module of 3rd Embodiment. It is a fragmentary sectional view which shows a part of modification of the composite assembled battery module of 3rd Embodiment. It is a fragmentary sectional view which shows a part of composite battery module of 4th Embodiment. It is the schematic of the motor vehicle carrying the composite assembled battery module of 3rd Embodiment.

Explanation of symbols

10, 10a, 10b battery pack,
11 Current collector,
11a Positive electrode side outermost layer current collector,
11b The negative electrode side outermost layer current collector,
13 positive electrode active material layer,
15 negative electrode active material layer,
17 electrolyte layer,
20, 20a, 20b, 20c Sheet battery (bipolar battery),
21 battery elements,
25 positive terminal,
27 negative terminal,
29 Laminate sheet,
33 cell layer,
35 insulation layer,
40 battery module,
42 convex parts,
44 recess,
46 Air gap,
50 composite battery module,
60 heat sink,
100 cars,
Cross-sectional area of S ₁ and S ₂ voids.

Claims (4)

A positive electrode connected to the battery element, in which a plurality of sheet-like batteries in which a battery element that is substantially similar to the exterior is sealed inside a substantially rectangular exterior is connected in series A terminal is derived from one side of the exterior, a negative electrode terminal connected to the battery element is derived from the other side of the exterior, and one sheet-shaped battery and another sheet-shaped battery adjacent thereto are An assembled battery module in which two assembled batteries are connected by joining a positive electrode terminal of one sheet-like battery and a negative electrode terminal of the other sheet-like battery , wherein the two assembled batteries are The assembled battery module, wherein the convex portions of the respective assembled batteries are combined in a facing direction, and the convex portion of one assembled battery of the two assembled batteries is fitted with the concave portion of the other assembled battery. The assembled battery module according to claim 1, wherein two assembled batteries constituting the assembled battery module are combined so as to form a gap in a fitting portion between the convex portion and the concave portion. In the cross section of the assembled battery module perpendicular to the side of the exterior, the cross-sectional area of the gap formed in the fitting portion between the convex portion and the concave portion is the cross-sectional area of the convex portion fitted into the fitting portion. The assembled battery module according to claim 2, wherein The assembled battery module of any one of Claims 1-3 in which the assembled battery which comprises an assembled battery module is connected in series or in parallel.

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