JP2006210185A - Cooling structure of secondary battery and cooling structure of battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the cooling structure of a secondary battery capable of sufficiently lowering the temperature of the battery and to provide the cooling structure of a battery pack. <P>SOLUTION: The cooling structure of a battery cell 10 comprises an electrode body 13 having a positive sheet, a separator, and a negative sheet, a laminate outer packaging 12 forming an internal space 11 and housing the electrode body 13 in the internal space 11, and a positive terminal 21 and a negative terminal 26 connected to the electrode body 13 in the internal space 11, projecting from the internal space 11 to the outside of the internal space 11, and extending from one ends 21m and 26m to the other ends 21n and 26n. Hollow parts 22 and 27 communicating with one ends 21m and 26m and the other ends 21n and 26n are formed in the positive terminal 21 and the negative terminal 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention generally relates to a cooling structure for a secondary battery and a cooling structure for an assembled battery. For example, a cooling structure for a secondary battery that is mounted on a hybrid vehicle and serves as a power source together with an internal combustion engine, and the secondary battery. The present invention relates to a cooling structure for a plurality of assembled batteries.

  Regarding a conventional secondary battery cooling structure, for example, Japanese Patent Laid-Open No. 2002-319388 discloses a lithium ion secondary battery for the purpose of suppressing temperature rise (Patent Document 1). The lithium ion secondary battery disclosed in Patent Document 1 includes a positive electrode terminal and a negative electrode terminal respectively connected to both ends of the electrode body. Heat dissipation fins are formed on the positive electrode terminal and the negative electrode terminal.

  Japanese Patent Laid-Open No. 2003-31206 discloses a lithium ion secondary battery for the purpose of simplifying the configuration (Patent Document 2). The lithium ion secondary battery disclosed in Patent Document 2 includes a container that houses an electrode body, and a positive electrode terminal and a negative electrode terminal that are connected to the electrode body. During the manufacturing process of the battery, the negative electrode terminal is formed with a through hole that communicates the inside and outside of the container. Japanese Patent Laid-Open No. 2000-260490 discloses an assembled battery for the purpose of preventing damage to a sensor or the like that detects a battery state (Patent Document 3).

Japanese Patent Application Laid-Open No. 2002-373638 discloses a battery that achieves weight reduction of the bus bar while supporting a large current and facilitates connection between the bus bar and the electrode ( Patent Document 4). The battery disclosed in Patent Document 4 is provided with a bus bar that is welded to the positive electrode and the negative electrode outside the case that houses the electrode stack, and electrically connects adjacent battery cells. The bus bar has an opening through which cooling air flows.
JP 2002-319388 A JP 2003-31206 A JP 2000-260490 A JP 2002-373638 A

  In the lithium ion secondary battery disclosed in Patent Document 1 described above, as the fin structure, for example, annular or spiral grooves are formed on the outer diameters of the positive electrode terminal and the negative electrode terminal. However, such a fin structure is formed only on a part of the positive electrode terminal and the negative electrode terminal, and the position where the fin structure is formed is also away from the electrode body that generates the largest amount of heat. For this reason, the cooling effect by the fin structure has little influence on the temperature of the entire battery, and it is difficult to sufficiently reduce the temperature of the battery.

  Accordingly, an object of the present invention is to solve the above-described problems and to provide a secondary battery cooling structure and an assembled battery cooling structure capable of sufficiently reducing the temperature of the battery.

  The cooling structure of the secondary battery according to the present invention includes an electrode body having a positive electrode sheet, a separator, and a negative electrode sheet, a container that forms an internal space and accommodates the electrode body in the internal space, and is connected to the electrode body in the internal space And a terminal protruding from the internal space to the outside of the internal space and extending from one end toward the other end. The terminal has a hollow portion that communicates between one end and the other end.

  According to the cooling structure of the secondary battery configured as described above, the surface area of the terminal is greatly increased by forming the hollow portion communicating with the one end and the other end in the terminal. For this reason, the heat which generate | occur | produced in the electrode body and was transmitted to the terminal from an electrode body can be discharge | released efficiently. Thereby, the temperature of the secondary battery can be sufficiently reduced.

  Preferably, cooling air flowing from one end to the other end is supplied to the hollow portion. According to the cooling structure of the secondary battery configured as described above, the cooling air continues to take heat from the terminal while being guided by the hollow portion and flowing between the one end and the other end. For this reason, heat dissipation from the terminal surface that defines the hollow portion can be performed more efficiently.

  Further, the electrode body is formed by winding a positive electrode sheet and a negative electrode sheet, which are overlapped via a separator, around a predetermined axis. The positive electrode sheet and the negative electrode sheet include a sheet peripheral portion that is overlapped in multiple layers in a radial direction centered on a predetermined axis in the state of an electrode body and connected to a terminal. Preferably, the sheet peripheral edge is in contact with the terminal over the entire radial direction centering on a predetermined axis. According to the secondary battery cooling structure configured as described above, the contact area between the sheet peripheral edge portion and the terminal is increased, so that heat generated in the electrode body can be efficiently transmitted to the terminal. Thereby, the temperature of the secondary battery can be further reduced.

  An assembled battery cooling structure according to the present invention is an assembled battery cooling structure obtained by combining a plurality of secondary battery cooling structures described above. The terminal has an outer surface facing away from the surface defining the hollow portion. The assembled battery cooling structure further includes a connection member that is provided on the outer surface and electrically connects terminals of the secondary batteries adjacent to each other.

  According to the assembled battery cooling structure configured as described above, since the connection member is provided on the outer surface of the terminal opposite to the hollow portion, the hollow portion is not blocked by the connection member. . For this reason, it can prevent that the heat dissipation from the terminal surface which prescribes | regulates a hollow part falls with a connection member.

  As described above, according to the present invention, it is possible to provide a secondary battery cooling structure and an assembled battery cooling structure capable of sufficiently reducing the temperature of the battery.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a battery cell according to an embodiment of the present invention. In the figure, a battery cell formed from a lithium ion secondary battery is shown. This battery cell is mounted on a hybrid vehicle, and forms an assembled battery that becomes a power source of the hybrid vehicle together with an internal combustion engine such as a gasoline engine or a diesel engine.

  Referring to FIG. 1, the battery cell 10 includes a wound electrode body 13, a positive terminal 21 and a negative terminal 26 connected to both ends of the electrode body 13, and an internal space 11 that houses the electrode body 13. And a laminate outer body 12 to be formed. The positive terminal 21 and the negative terminal 26 are formed with hollow portions 22 and 27 extending in one direction, respectively. The positive electrode terminal 21 and the negative electrode terminal 26 are formed in a cylindrical shape.

FIG. 2 is a perspective view showing the electrode body in FIG. FIG. 3 is an exploded view of the electrode body in FIG. 2 and 3, the electrode body 13 includes a positive electrode sheet 17 and a negative electrode sheet 14 that is superimposed on the positive electrode sheet 17 via a separator 20. The positive electrode sheet 17 is formed from an aluminum foil having a substantially rectangular shape. A paste 18 containing a positive electrode active material is applied to both surfaces of the positive electrode sheet 17. As the positive electrode active material, one or more of the positive electrode active materials used in the lithium ion secondary battery such as LiMn ₂ O ₄ , LiCoO ₂ , LiNiO ₃ can be used without any particular limitation. On one peripheral edge along the longitudinal direction of the positive electrode sheet 17, a paste non-applied portion 19 to which the paste 18 is not applied is formed to extend in a band shape.

  The negative electrode sheet 14 is formed from a copper foil having the same shape as the positive electrode sheet 17. A paste 15 containing a negative electrode active material is applied to both surfaces of the negative electrode sheet 14. As the negative electrode active material, one type or two or more types of negative electrode active materials used for lithium ion secondary batteries, such as amorphous carbon and graphite carbon, can be used without particular limitation. On one peripheral edge along the longitudinal direction of the negative electrode sheet 14, a paste non-applied portion 16 to which the paste 15 is not applied is formed extending in a band shape.

  The separator 20 has a substantially rectangular shape that is shorter than the positive electrode sheet 17 and the negative electrode sheet 14 in the short direction. As the separator 20, for example, a porous polypropylene resin sheet can be used.

  The positive electrode sheet 17, the negative electrode sheet 14, and the two separators 20 are stacked in the order of the separator 20, the negative electrode sheet 14, the separator 20, and the positive electrode sheet 17. At this time, the region where the paste 18 is applied to the positive electrode sheet 17 and the region where the paste 15 is applied to the negative electrode sheet 14 face each other through the separator 20. Further, the paste unapplied portion 19 of the positive electrode sheet 17 is exposed from one end side extending in the longitudinal direction of the separator 20, and the other end side of the negative electrode sheet 14 extending in the longitudinal direction of the separator 20 is exposed. Exposed from.

  The electrode body 13 is formed by winding a laminated body including a positive electrode sheet 17, a negative electrode sheet 14, and two separators 20 around a central axis 101. The laminated body is wound so that the cross-sectional shape when it is cut along a plane orthogonal to the central axis 101 is an ellipse. A positive electrode current collector 36 connected to the positive electrode terminal 21 and a negative electrode current collector 37 connected to the negative electrode terminal 26 are formed at both ends of the electrode body 13 separated in the direction along the central axis 101. . The positive electrode current collector 36 is formed by overlapping the paste uncoated portions 19 of the positive electrode sheet 17 in multiple layers in the radial direction around the central axis 101. The negative electrode current collector 37 is formed by overlapping the paste-uncoated portion 16 of the negative electrode sheet 14 in multiple layers in the radial direction with the central axis 101 as the center. The electrode body 13 is impregnated with an organic electrolyte obtained by dissolving a lithium salt in an organic solvent.

  FIG. 4 is an exploded view of the battery cell in FIG. Referring to FIGS. 1 and 4, positive terminal 21 and negative terminal 26 are made of metal. The positive terminal 21 is made of, for example, aluminum, and the negative terminal 26 is made of, for example, copper.

  The positive electrode terminal 21 has one end 21m and the other end 21n, and the negative electrode terminal 26 has one end 26m and the other end 26n. The positive terminal 21 has a hollow portion 22 that extends from one end 21 m to the other end 21 n and extends in the direction indicated by the arrow 102. The negative electrode terminal 26 is formed with a hollow portion 27 that extends from one end 26 m to the other end 26 n and extends in the same direction as the hollow portion 22. The hollow portions 22 and 27 have a substantially circular cross-sectional shape.

  The cross-sectional shapes of the hollow portions 22 and 27 are not limited to a substantially circular shape, and may be an appropriate shape such as a rectangular shape or an elliptical shape. Further, the hollow portions 22 and 27 may be formed between the one end 21m and the other end 21n and between the one end 26m and the other end 26n while changing the extending direction in the middle. Moreover, the hollow part 22 or 27 should just be formed in at least any one of the positive electrode terminal 21 and the negative electrode terminal 26. FIG.

  The positive electrode terminal 21 has an inner peripheral surface 21b that defines the hollow portion 22, and an outer peripheral surface 21a that is located on the back side of the inner peripheral surface 21b and exposed to the outside. The negative electrode terminal 26 has an inner peripheral surface 26b that defines the hollow portion 27, and an outer peripheral surface 26a that is positioned on the back side of the inner peripheral surface 26b and exposed to the outside. The positive electrode terminal 21 has a plurality of slits 31 extending from the outer peripheral surface 21a to the inner peripheral surface 21b. A plurality of slits 32 extending from the outer peripheral surface 26a to the inner peripheral surface 26b are formed in the negative electrode terminal 26. A male screw 23 is formed on the outer peripheral surface 21 a between the one end 21 m and the slit 31. A male screw 28 is formed on the outer peripheral surface 26 a so as to be positioned between the one end 26 m and the slit 32.

  The positive electrode current collector 36 is entirely inserted into the slit 31, whereby the positive electrode terminal 21 and the positive electrode sheet 17 of the electrode body 13 are electrically connected. The negative electrode current collector 37 is entirely inserted into the slit 32, whereby the negative electrode terminal 26 and the negative electrode sheet 14 of the electrode body 13 are electrically connected. The positive electrode current collector 36 and the negative electrode current collector 37 are fixed to the positive electrode terminal 21 and the negative electrode terminal 26 by being inserted into the slits 31 and 32 and then welded from the inner peripheral surfaces 21b and 26b. . With such a connection method, the positive electrode current collector 36 and the negative electrode current collector 37 are in contact with the positive electrode terminal 21 and the negative electrode terminal 26 over the entire radial direction around the central axis 101, respectively.

  The laminate outer package 12 is formed by coating a base material made of a metal such as aluminum with a resin material such as polyethylene terephthalate (PET). The laminate outer body 12 includes a central portion 12r that forms the internal space 11 that accommodates the electrode body 13, and both end portions 12p and 12q that are located on both sides of the central portion 12r and cover a part of the outer peripheral surfaces 21a and 26a, respectively. It is composed of The laminate exterior body 12 is formed by integrating a central portion 12r, both end portions 12p, and both end portions 12q. The regions between the one end 21m and the slit 31 and between the one end 26m and the slit 32 where the male screws 23 and 28 are formed are exposed from both end portions 12p and 12q. The thickness of the laminate outer package 12 is, for example, 1 mm or less. The laminate outer package 12 is provided by a general heat welding process.

  Thus, by covering the positive electrode terminal 21 and the negative electrode terminal 26 with the laminate body 12 together with the electrode body 13, it is possible to reliably prevent the electrolyte impregnated in the electrode body 13 from leaking to the outside of the laminate exterior body 12.

  In the present embodiment, the laminate exterior body 12 is used as a container for forming the internal space 11, but a metal case body may be used instead of the laminate exterior body 12. In this case, the case body is provided with an insulating structure for insulating between the positive electrode terminal 21 and the negative electrode terminal 26.

  In a state where the positive electrode terminal 21 and the negative electrode terminal 26 are fixed to the electrode body 13, the direction indicated by the arrow 102 in which the hollow portions 22 and 27 extend is orthogonal to the direction in which the central axis 101 that is the winding center of the electrode body 13 extends. . The hollow portions 22 and 27 are opened at a position away from the laminate outer package 12. For this reason, the hollow portions 22 and 27 are not blocked by the laminate outer package 12.

  FIG. 5 is a perspective view showing an assembled battery in which a plurality of battery cells in FIG. 1 are combined. FIG. 6 is a top view of the assembled battery in FIG. FIG. 7 is an exploded view showing a position surrounded by a two-dot chain line VII in FIG.

  With reference to FIGS. 5 to 7, the battery pack 41 accommodates an assembled battery 40 in which a plurality of battery cells 10 are connected in series. In the plurality of battery cells 10, the positive electrode terminal 21 of the battery cell 10p adjacent to each other and the negative electrode terminal 26 of the battery cell 10q face each other, and the negative electrode terminal 26 of the battery cell 10p and the positive electrode terminal 21 of the battery cell 10q face each other. Are arranged in one direction. A harmonica tube 46 is inserted between the battery cells 10 adjacent to each other. The harmonica tube 46 is formed with a vent hole 47 extending in the same direction as the hollow portions 22 and 27. A plurality of ventilation holes 47 are formed side by side in the direction connecting the positive electrode terminal 21 and the negative electrode terminal 26.

  By the bus bar 51, the positive terminal 21 of the battery cell 10 is electrically connected to the negative terminal 26 of the battery cell 10 adjacent to one side, and the negative terminal 26 of the battery cell 10 is adjacent to the other side. The battery cell 10 is electrically connected to the positive electrode terminal 21. At both ends of the bus bar 51, through holes 52 into which one end 21m of the positive electrode terminal 21 and one end 26m of the negative electrode terminal 26 are inserted are formed. In a state where the one ends 21 m and 26 m are inserted into the through hole 52, the nut 55 is tightened on the male screws 23 and 28. With such a configuration, the bus bar 51 is fixed to the positive electrode terminal 21 and the negative electrode terminal 26 only in contact with the outer peripheral surfaces 21a and 26a without contacting the inner peripheral surface 21b and the inner peripheral surface 26b.

  A cooling air supply duct 43 provided with a blower fan 42 and a cooling air discharge duct 44 are connected to the battery pack 41. When the blower fan 42 is operated, air in the vehicle compartment is taken into the battery pack 41 from the cooling air supply duct 43 as cooling air. The taken cooling air flows through the ventilation holes 47 and the hollow portions 22 and 27 simultaneously in the battery pack 41.

  At this time, since the ventilation holes 47 and the hollow portions 22 and 27 are formed to extend in the same direction, it is possible to prevent the cooling air flow in the battery pack 41 from being disturbed. Thereby, the several battery cell 10 accommodated in the battery pack 41 can be cooled more uniformly. Further, since the bus bar 51 is provided in contact with the outer peripheral surfaces 21a and 26a, the cooling air flow in the hollow portions 22 and 27 is not inhibited by the bus bar 51. Further, since the hollow portions 22 and 27 are opened at a position away from the laminate exterior body 12, the cooling air flow in the hollow portions 22 and 27 is not inhibited by the laminate exterior body 12. After the cooling air flows through the ventilation holes 47 and the hollow portions 22 and 27, the cooling air is discharged from the cooling air discharge duct 44 into the trunk room or outside the vehicle.

  The electrode body 13, the positive electrode terminal 21, and the negative electrode terminal 26 are made of a metal having excellent thermal conductivity and are directly connected to each other. Further, the positive electrode current collector 36 and the negative electrode current collector 37 are in contact with the positive electrode terminal 21 and the negative electrode terminal 26 over the entire radial direction centering on the central axis 101, respectively. For this reason, the heat generated in the electrode body 13 is efficiently transmitted from the electrode body 13 to the positive electrode terminal 21 and the negative electrode terminal 26.

  In the present embodiment, hollow portions 22 and 27 are formed in the positive electrode terminal 21 and the negative electrode terminal 26, respectively. For this reason, the surface areas of the positive electrode terminal 21 and the negative electrode terminal 26 are increased by the inner peripheral surfaces 21 b and 26 b that define the hollow portions 22 and 27. In addition, cooling air flows through the hollow portions 22 and 27, and heat exchange is positively performed between the inner peripheral surfaces 21b and 26b and the cooling air. For these reasons, the amount of heat released from the positive terminal 21 and the negative terminal 26 can be greatly increased. Thereby, cooling of the battery cell 10 can be performed efficiently.

  The cooling structure of the battery cell 10 as the secondary battery in the embodiment of the present invention includes an electrode body 13 having a positive electrode sheet 17, a separator 20 and a negative electrode sheet 14, an internal space 11, and the electrode body in the internal space 11. 13 is connected to the electrode body 13 in the internal space 11, protrudes from the internal space 11 to the outside of the internal space 11, and extends from one end 21m and 26m toward the other end 21n and 26n. A positive electrode terminal 21 and a negative electrode terminal 26 are provided as extending terminals. The positive electrode terminal 21 and the negative electrode terminal 26 are formed with hollow portions 22 and 27 communicating with one end 21m and 26m and the other end 21n and 26n.

  The electrode body 13 is formed by winding the positive electrode sheet 17 and the negative electrode sheet 14 that are overlapped via the separator 20 around a central axis 101 as a predetermined axis. The positive electrode sheet 17 and the negative electrode sheet 14 are stacked in multiple layers in the radial direction around the central axis 101 in the state of the electrode body 13, and a positive electrode current collector 36 as a sheet peripheral edge connected to the positive electrode terminal 21 and the negative electrode terminal 26. And a negative electrode current collector 37. The positive electrode current collector 36 and the negative electrode current collector 37 are in contact with the positive electrode terminal 21 and the negative electrode terminal 26 over the entire radial direction around the central axis 101.

  The positive electrode terminal 21 and the negative electrode terminal 26 are located between one end 21m and 26m and the other end 21n and 26n, and are connected to the electrode body 13. The hollow portions 22 and 27 are formed adjacent to positions where the positive electrode terminal 21 and the negative electrode terminal 26 are connected to the electrode body 13. The assembled battery 40 further includes a harmonica tube 46 as a spacer member disposed between adjacent battery cells 10. The harmonica tube 46 is formed with a vent hole 47 extending in parallel with the hollow portions 22 and 27.

  In the present embodiment, the case where the battery cell 10 is a lithium ion secondary battery has been described. However, the battery cell 10 may be a secondary battery other than this, for example, a nickel hydrogen secondary battery. In this case, the electrode body constituting the nickel metal hydride secondary battery is formed, for example, such that comb-like positive electrode sheets and negative electrode sheets arranged so as to face each other are alternately meshed with each other via the separator.

  According to the cooling structure of battery cell 10 and assembled battery 40 according to the embodiment of the present invention configured as described above, battery cell 10 can be efficiently cooled. Thereby, the performance and reliability of the hybrid vehicle on which the assembled battery 40 is mounted can be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a perspective view which shows the battery cell in embodiment of this invention. It is a perspective view which shows the electrode body in FIG. FIG. 2 is an exploded view of the electrode body in FIG. 1. FIG. 2 is an exploded view of the battery cell in FIG. 1. It is a perspective view which shows the assembled battery comprised by combining several battery cells in FIG. It is a top view of the assembled battery in FIG. FIG. 7 is an exploded view showing a position surrounded by a two-dot chain line VII in FIG. 6.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Battery cell, 11 Internal space, 12 Laminate exterior body, 13 Electrode body, 14 Negative electrode sheet, 17 Positive electrode sheet, 20 Separator, 21 Positive electrode terminal, 21a, 26a Outer surface, 21b, 26b Inner surface, 21m, 26m One end , 21n, 26n, the other end, 22, 27 hollow part, 26 negative electrode terminal, 36 positive electrode current collector part, 37 negative electrode current collector part, 40 assembled battery, 51 bus bar, 101 central axis.

Claims (4)

An electrode body having a positive electrode sheet, a separator and a negative electrode sheet;
A container that forms an internal space and accommodates the electrode body in the internal space;
A terminal connected to the electrode body in the internal space, protruding from the internal space to the outside of the internal space, and extending from one end toward the other end;
A cooling structure for a secondary battery, wherein the terminal is formed with a hollow portion communicating between the one end and the other end.   The cooling structure of the secondary battery according to claim 1, wherein cooling air that flows from the one end toward the other end is supplied to the hollow portion. The electrode body is formed by winding the positive electrode sheet and the negative electrode sheet, which are overlapped via the separator, around a predetermined axis,
The positive electrode sheet and the negative electrode sheet are stacked in multiple layers in the radial direction around the predetermined axis in the state of the electrode body, and include a sheet peripheral edge portion connected to the terminal,
3. The cooling structure for a secondary battery according to claim 1, wherein the peripheral edge of the sheet is in contact with the terminal over the entire radial direction centering on the predetermined axis. A cooling structure for an assembled battery in which a plurality of secondary battery cooling structures according to any one of claims 1 to 3 are combined,
The terminal has an outer surface facing away from the surface defining the hollow portion;
A cooling structure for an assembled battery, further comprising a connection member provided on the outer surface and electrically connecting the terminals of the secondary batteries adjacent to each other.

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