JP2007109547A - Cooling structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure capable of cooling uniformly each film package electric device in a module. <P>SOLUTION: A module 30A and a module 30B are arranged so that the cross-section of a merging path 22 of cooling air formed between the module 30A and the module 30B may be expanded toward discharge port 60. The cooling air is supplied to a gap 21A of the module 30A toward an arrow α direction which is a direction progressing toward the adjoining module 30B, and the cooling air is supplied to a gap of the module 30B toward a β direction in the opposite direction to the α direction, and each cooling air is joined in the confluence path 22, and then discharged to the outside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a cooling structure that cools an electric device assembly configured by assembling a plurality of film-clad electrical devices (for example, film-clad batteries) with cooling air.

  In recent years, as a power source for driving an electric vehicle or the like, for example, an assembled battery including a plurality of film-clad batteries functioning as a lithium ion secondary battery is used. Further, in such an assembled battery, it is known that each film-covered battery needs to be cooled in order to maximize the charge / discharge performance of the battery (or not to shorten the battery life). ing.

  When forming an assembled battery, a method of stacking batteries and storing them in a battery case is generally employed. In such a case, cooling air flows through the gaps between the stacked batteries (for example, Patent Document 1).

By the way, in configuring an assembled battery, the battery cells may be arranged side by side in a plane (such an arrangement is hereinafter referred to as “flat placement”). FIG. 4 schematically shows a state in which the battery cells 120A and 120B that are placed flat are stacked. In such a case, the cooling air is supplied from the battery cell 120A side (or from the 120B side), passes through the gap 121A between the stacked battery cells 120A, and then passes through the gap 121b between the stacked battery cells 120B. It is discharged after.
JP 2004-39484 A

  However, when cooling an assembled battery as shown in FIG. 4, even if it is sent from one battery cell side (120A side) to the other battery cell side (120B side), one battery cell and the other battery It is difficult to cool the cell uniformly. That is, the cooling air is warmed when it passes through one battery cell 120A, and this warm cooling air is supplied to the other battery cell 120B, so that there is a cooling effect between the two battery cells. Because it is different.

  As described above, the film-clad battery has been described as an example. However, the above-described problem is not limited to the battery, and may occur in a device in which a capacitor or the like is disposed as an electric device element in a film package, for example. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cooling structure for an electric device assembly capable of uniformly cooling each film-covered electric device constituting the electric device assembly. Is to provide.

  In order to achieve the above object, according to the cooling structure for an electric device assembly of the present invention, the electric device element for storing and outputting electric energy is accommodated in the film package, and the electrode tab is drawn out from the sealing portion of the film package. In the cooling structure for cooling an electric device assembly formed by laminating a plurality of film-clad electric devices with a gap, the electric device assembly is formed between one electric device assembly and another electric device assembly. One electrical device assembly and another electrical device assembly are arranged so that the cross-sectional area of the cooling air flow path expands in one direction. Is supplied with cooling air toward a first direction that is a direction of another adjacent electric device assembly, and a gap between the other electric device assemblies is a second direction opposite to the first direction. Cooled air is supplied toward each cooling air characterized in that it is discharged from the joins in the flow path to the outside.

  Since the cooling structure of the present invention individually supplies cooling air to each electric device assembly, uniform cooling of the battery can be realized as compared with a method of sequentially cooling from one direction.

  In addition, the above arrangement expands the cross-section of the flow path according to the flow rate of the cooling air that increases toward the discharge port from which the cooling air is discharged, so that the cooling air stays in the gap near the discharge port. Therefore, it is possible to prevent a cooling imbalance between the film-covered electrical device near the discharge port and the distant film-covered electrical device.

  Further, in the cooling structure of the present invention, the merging of the cooling air in the flow path may be merged with an angle in the direction toward the cooling air discharge port in the flow path. In this case, the cooling air can be efficiently discharged because the air is merged obliquely in the direction toward the discharge port.

  In the cooling structure of the present invention, one electrical device assembly and another electrical device assembly may be arranged so that the cooling air discharge port in the flow channel faces upward in the vertical direction. . In this case, it is possible to use natural convection of cooling air that has taken the heat of the film-covered electrical device and has reached a high temperature. That is, when the discharge port is directed upward, it is possible to omit a fan for sending cooling air into the gap and to reduce the capacity.

  In the cooling structure of the present invention, the space formed between the electric device assemblies is also used as an exhaust gas passage for guiding the gas discharged from the film-covered electric device to the outside. Also good. In this case, since it is not necessary to provide a separate exhaust gas passage or a separate cooling channel, a simple configuration can be achieved.

  As described above, according to the present invention, since cooling air is individually supplied to each electric device assembly, uniform battery cooling can be realized as compared with a method of sequentially cooling from one direction.

  FIG. 1 shows a partially broken perspective view of a film-clad battery applicable to this embodiment. FIG. 2 shows a plan view of a cell case that houses the battery cell 20. FIG. 3 is a schematic diagram showing the arrangement of battery cells housed in the cell case and the flow of cooling air in the assembled battery of this embodiment.

  As the battery cell 20, it is possible to use a conventional general film-clad battery as shown in FIG. The battery cell 20 is a lithium ion secondary battery in which a battery element 52 is accommodated together with an electrolytic solution in a sealed space formed by two exterior films 24 constituting a film package. Four sides of the outer peripheral portion of the exterior film 24 are sealing portions 23 in which the films are heat-sealed, and among these, sheet-like electrode tabs 25a and 25b are drawn out from two sides on the short side.

  Each exterior film 24 is formed with a cup portion (not shown with a symbol) having a shape corresponding to the battery element 52. The cup portion includes a flat central portion 26a formed in a region covering the upper surface (or lower surface) of the battery element 52 and an inclined surface 26b formed around the center portion 26a. When the battery cell 20 is cooled, it is most effective to cool the central portion 26a.

  The cell case 50 surrounding the battery cell 20 has a frame shape, and an opening is formed at a location corresponding to the power generation element 52 of the battery cell 20.

  The cell case 50 is a rectangular frame composed of two opposing side walls 50a and two short side walls 50b that are substantially orthogonal to the side walls 50a and are opposed to each other. Each short side wall 50b of the cell case 50 is formed with a notch 50e for extending the electrode of the battery cell 20 accommodated in the cell case 50 to the outside. The battery cell 20 is housed in the cell case 50 with the electrode extended in this manner.

  The side wall 50a is connected by an exhaust gas passage 51c for guiding the gas discharged from the gas discharge portion 8 of the battery cell 20 to the outside. In this embodiment, since the gas discharge part 8 of the battery cell 20 is formed in the approximate center of the sealing part 23, the exhaust gas passage 51c is also formed in the approximate center of the side wall 50a accordingly. The gas discharged from the gas discharge portion 8 is discharged to the outside through the exhaust gas passage 51c.

  The battery cells 20 housed in the cell case 50 are stacked and modularized. FIG. 3 shows a module 30A in which four battery cells 20A are stacked with a gap 21A and a module 30B in which four battery cells 20B are stacked with a gap 21B.

  The module A and the module B substantially contact one end of the lowermost cell case 50 of the module A and one end of the lowermost cell case 50 of the module B (at a contact point 70 shown in FIG. 3). The confluence channel 22 having a sandwiching angle θ (which is in contact with each other) is disposed. That is, as shown in FIG. 3, the cooling air that has flowed into the gaps 21 </ b> A and 21 </ b> B from the outside of the modules 30 </ b> A and 30 </ b> B and has flowed into the combined flow path 22 formed between the modules 30 </ b> A and 30 </ b> B The modules 30 </ b> A and 30 </ b> B are arranged so as to flow without stagnation in the combined flow path 22 that expands toward the surface. The combined flow path 22 is a cooling air flow path, and is also used as a gas flow path through which the gas discharged from the gas discharge section 8 flows.

  Hereinafter, the flow of cooling air and the cooling characteristics will be described in detail.

  Cooling air is supplied to the gap 21A of the module 30A from the direction of the arrow α to remove heat from the central portion 26a of the battery cell 20 (the cooling air flows from one side wall 50a to the other side wall 50a with respect to the cell case 50. In the direction indicated by the arrow α (see FIG. 2), and flows out to the combined flow path 22.

  Since the combined flow path 22 is configured to open toward the discharge port 60 at the sandwiching angle θ, the cooling air flowing out from the gap 21A has an angle of π−θ with respect to the flow direction of the cooling air flowing out from the gap 21B. It will hit you. That is, the cooling air that flows out from the gap 21A and the gap 21B does not merge so as to collide in front of each other, but merges at an angle toward the discharge port 60. The current is rectified to face 60. When the cooling air is merged so that they collide in front of each other, the cooling air generates a flow toward the discharge port 60 and a flow toward the direction away from the discharge port 60, and the cooling air is efficiently discharged from the discharge port 60. I can't. However, in the case of this embodiment, since it merges diagonally in the direction which goes to the discharge port 60, a cooling wind can be discharged | emitted efficiently.

  In the case of this embodiment, the cooling air is supplied to each of the module 30A and the module 30B. The method of cooling the battery cell 20B after the cooling air supplied from one direction of the arrow α has cooled the battery cell 20A has a problem that the battery cell 20B to be cooled later is not sufficiently cooled. In the embodiment, since the battery cells 20A and 20B are separately cooled, both the battery cells 20A and 20B can be cooled equally and satisfactorily.

Further, since the cooling air flowing into the combined flow path 22 sequentially flows from the contact point 70 side toward the discharge port 60, the flow rate increases toward the discharge port 60. When the combined flow path 22 has a constant flow path cross section up to the discharge port 60 side, the flow rate of the cooling air in the combined flow path 22 is increased in the vicinity of the discharge port 60, so the combined flow paths from the gaps 21 </ b> A and 21 </ b> B near the discharge port 60. It becomes difficult for the cooling air to flow into 22. That is, the cooling air that has taken away heat from the battery cell 20 and has reached a high temperature stays in the gap without going out to the combined flow path 22, and the temperature of the battery cells 20 A ₁ and 20 B _{1 in} the vicinity of the discharge port 60 becomes the discharge port. It is considered that the temperature becomes higher than the temperature of the battery cells 20A ₄ and 20B _{4 at} a distance of 60, causing non-uniform cooling.

On the other hand, the flow path cross-sectional area of the combined flow path 22 of the present embodiment expands toward the discharge port 60 in accordance with the flow rate that increases toward the discharge port 60. For this reason, even if the cooling air flow rate increases toward the discharge port 60, it is possible to prevent the cooling air from staying in the gaps 21A and 21B near the discharge port 60. That is, the configuration of the present embodiment is a configuration in which uneven cooling between the battery cells 20A ₁ and 20B ₁ near the discharge port 60 and the battery cells 20A ₄ and 20B ₄ far from the discharge port 60 hardly occurs. .

  Further, the stacking direction of the battery cells 20 may be horizontal, but by stacking so that the discharge ports 60 face upward, it is possible to use natural convection of cooling air that has taken away the heat of the battery cells and has become high temperature. it can. That is, when the discharge port 60 faces upward, it is possible to omit a fan for sending cooling air into the gaps 21A and 21B and to reduce the capacity.

  As described above, according to the present embodiment, since cooling air is individually supplied to the modules 30A and 30B, uniform battery cooling can be realized as compared with a method of sequentially cooling from one direction.

  Moreover, in the case of this embodiment, since it merges diagonally in the direction which goes to a discharge port, a cooling wind can be discharged | emitted efficiently.

  In the case of this embodiment, since the cross section of the flow path is expanded according to the cooling air flow rate that increases toward the discharge port, it is possible to prevent the cooling air from staying in the gap in the vicinity of the discharge port. It is possible to prevent a cooling imbalance between the battery cells in the vicinity of the outlet and the distant battery cells.

  In the present embodiment, a member for forming the cooling path is not particularly used, but the flow path is formed using the wall surface of the cell case, which is advantageous in terms of cost.

  In the case of the present embodiment, the combined flow path 22 is also used as a gas path that is discharged from the gas discharge section 8 and passes through the exhaust gas passage 51c, so that it is not necessary to separately form a flow path for exhaust gas. Therefore, the configuration can be simplified.

  In the present embodiment, the cooling air discharged from the gap 21 has been shown as hitting the side wall of the cell case at the opposite position. However, the present invention is not limited to this. In other words, the battery cells may be stacked without using the cell case. In this case, since the cell case is omitted, the weight is reduced, which is advantageous in terms of weight.

  In the above description, the example in which the module 30A and the module 30B are brought into contact with each other at the contact point 70 is shown, but the present invention is not limited to this. That is, if the inter-module distance on the discharge port 60 side is larger than the inter-module distance on the far side of the discharge port 60, the flow path cross section of the combined flow path 22 is configured to expand toward the discharge port 60. The modules do not have to be in actual contact with each other.

  Although not described in detail in the above description, the battery element 52 constituting the lithium ion secondary battery is specifically made of a positive electrode active material such as lithium / manganese composite oxide or lithium cobaltate made of aluminum foil or the like. Alternatively, a positive electrode plate coated on both surfaces and a negative electrode plate coated with a lithium-doped / dedoped carbon material on both surfaces such as a copper foil may be alternately stacked via separators. In addition to the lithium ion secondary battery, the battery element 52 may constitute another type of chemical battery such as a nickel metal hydride battery, a nickel cadmium battery, a lithium metal primary battery or secondary battery, or a lithium polymer battery. Good. Further, the battery element 52 is not limited to the stacked type as in the present embodiment, and a belt-like positive electrode side active electrode and a negative electrode side active electrode are stacked with a separator interposed between them, and then compressed into a flat shape. Thus, a wound type having a structure in which the positive electrode side active electrode and the negative electrode side active electrode are alternately laminated may be used. The electric device element constituting the film-clad electric device may be a capacitor such as an electric double layer capacitor or a capacitor element exemplified by an electrolytic capacitor.

  Moreover, the exterior film 24 is a laminate film, for example, and any laminate film may be used as long as the battery element can be hermetically sealed. To give a specific example, a resin layer that is heat-meltable and serves as an inner surface, a non-venting layer made of a metal thin film, and a protective layer (such as nylon) that are laminated on the outer surface are laminated in this order. A laminated film may be used. Further, the film package is not limited to the one constituted by the two exterior films 24, and may be a package in which, for example, one exterior film is folded and its three sides are heat-sealed. The drawing position of each electrode tab 25 is not particularly limited, and two electrode tabs for the positive electrode and the negative electrode may be drawn from one side of the sealing portion of the film package.

It is a partially broken perspective view of a film-clad battery applicable to the present invention. It is a top view of the storage case which stores a battery cell. It is a schematic diagram which shows the arrangement | sequence of the battery cell accommodated in the storage case, and the flow of cooling air in the assembled battery of this invention. It is a schematic diagram for demonstrating the cooling condition of the conventional flat battery.

Explanation of symbols

8 Gas discharge part 20, 20A, 20B Battery cell 21A, 21B Gap 22 Joint flow path 23 Sealing part 24 Exterior film 25a, 25b Electrode tab 26a Central part 26b Inclined surface 30A, 30B Module 50 Cell case 50a Side wall 50e Notch 50b Short side wall 51c Exhaust gas passage 60 Discharge port 52 Battery element

Claims (4)

An electrical device element that stores and outputs electrical energy is housed in a film package, and electrode tabs are drawn from the sealing portion of the film package, and a plurality of film-covered electrical devices are stacked with a gap therebetween. In the cooling structure for cooling the electrical device assembly,
The one electric device so that the cross-sectional area of the flow path of the cooling air formed between the one electric device assembly and the other electric device assembly expands in one direction. An assembly and the other electrical device assembly are arranged, and a gap between one electrical device assembly is directed toward a first direction that is a direction of the other adjacent electrical device assembly. Cooling air is supplied, and cooling air is supplied to a gap between the other electric device assemblies in a second direction opposite to the first direction, and the cooling air merges in the flow path. A cooling structure for an electrical device assembly, wherein the electrical device assembly is discharged outside.   The cooling structure according to claim 1, wherein the merging of the cooling air in the flow path merges at an angle in a direction toward the cooling air discharge port in the flow path.   The cooling according to claim 1 or 2, wherein the one electrical device assembly and the other electrical device assembly are arranged so that a cooling air discharge port in the flow path faces vertically upward. Construction.   The said space formed between each said electric device aggregate | assembly is combined with the waste gas passage for guiding the gas discharged | emitted from the film-clad electrical device outside, The any one of Claim 1 thru | or 3 The cooling structure as described in.

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