JP2014093244A - Heat transfer structure of battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat transfer structure of a battery module in which a cell expansion space can be secured compatibly with improvement of temperature control performance.SOLUTION: An end face of a cell unit 21 and a central portion of a side face of a module case 23 are abutted via an insulator 24, and the periphery thereof is defined as a void δ where surfaces are separated from each other, thereby securing an expansion space in a laminating direction of cells 22. A heat transfer sheet 25 is interposed in the void δ at a lower side close to a heat conduction plate 6 by filling this void. Thus, a heat transfer passage from the cell unit 21 to the heat conduction plate 6 is shortened and improvement of temperature control performance is attained.

Description

  The present invention relates to a heat transfer structure of a battery module constituting an assembled battery mounted on an electric vehicle or a hybrid vehicle.

  In Patent Document 1, a heat transfer substrate is provided as a temperature control means on the lower side of an assembled battery configured by stacking and arranging a plurality of battery modules in a vertical arrangement so that the assembled battery can be cooled or heated. It is shown.

  Patent Document 2 discloses a structure in which a battery module includes a cell unit in which a plurality of flat cells are stacked and a module case in which the cell unit is stored.

JP 2001-23703 A JP 2006-344520 A

  Since the cell expands in the thickness direction due to heat generation, it is necessary to secure a cell expansion space between the end surface of the cell unit of the laminate and the side surface of the module case.

  As one of the means, the end surface of the cell unit in the cell stacking direction and the side surface of the module case corresponding to the cell unit are in contact with each other through an insulator so that the surfaces are separated from each other. A void is formed, and this void is used as a cell expansion space.

  However, when a plurality of battery modules having this structure are stacked in a vertical arrangement as in the technology disclosed in Patent Document 1 and the temperature control means is provided on the lower side, the end surface of the cell unit and the side surface of the module case Heat transfer between the two is constrained to the central portion where they abut.

  For this reason, the heat transfer path | route from a cell unit to a temperature control means becomes long, and the problem that temperature control performance is inferior arises.

  Accordingly, the present invention provides a heat transfer structure for a battery module that can achieve both the securing of a cell expansion space and the improvement of temperature control performance.

  The battery module transmission structure of the present invention includes a battery module including a cell unit in which a plurality of flat cells are stacked and a module case in which the cell unit is stored, and the battery module is heated from the peripheral side thereof. And a temperature control means for cooling.

  The end surface of the cell unit in the cell stacking direction and the side surface of the module case corresponding to the end surface are formed as a space in which the central portion is in contact with each other via an insulator and the surfaces are separated from each other. Yes.

The main feature is that at least the gap close to the temperature adjusting means is filled and a heat conductive material is interposed.

  According to the present invention, since the heat transfer path from the cell to the temperature control means is shortened due to the presence of the heat conductive material, the temperature control performance can be improved.

  On the other hand, a gap exists between the end surface of the cell unit and the side surface of the corresponding module case, and when the cell expands in the stacking direction, this gap can be used as a cell expansion space.

  Thereby, coexistence with ensuring of the swelling space of a cell and improvement of temperature control performance is realizable.

The perspective view which decomposes | disassembles and shows the assembled battery and temperature control means which are the object of this invention. Cross-sectional explanatory drawing which shows the arrangement | positioning relationship between the battery module single-piece | unit and temperature control means in 1st Embodiment of this invention. Cross-sectional explanatory drawing which shows the cell expansion | swelling state in 1st Embodiment. Sectional explanatory drawing similar to FIG. 2 which shows 2nd Embodiment of this invention. Sectional explanatory drawing similar to FIG. 2 which shows 3rd Embodiment of this invention. The enlarged view of the A range part of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the relationship between the assembled battery 1 and the temperature control means 6 that are the subject of the present invention.

  The assembled battery 1 includes a plurality of thin rectangular battery modules 2 stacked vertically, a pair of holding plates 3 disposed on both sides in the stacking direction, and a pair of bundles disposed on both sides in the direction perpendicular to the stacking direction. The band plate 4 is integrally bound and fixed.

  And this assembled battery 1 is accommodated in the battery case 5 which consists of a metal with light weight and favorable heat conductivity, such as aluminum and an aluminum alloy.

  The temperature control means 6 is configured as a square heat conduction board and is disposed on the bottom surface of the bottom wall of the battery case 5 described above.

  The heat conduction board 6 is made of a material having good heat conductivity such as aluminum, aluminum alloy, ceramic or the like.

  This heat conduction board 6 is connected to a general-purpose refrigeration cycle or heat pump cycle via an inlet 6a and an outlet 6b of the heat medium, and introduces a liquid heat medium into the battery case 5 and the assembled battery 1 It actively cools or warms it.

  That is, when the assembled battery 1 generates heat during charging or discharging, the assembled battery 1 is cooled by introducing a heat medium from the refrigeration cycle, and the heat medium from the heat pump cycle is introduced during cold start in a cold district or the like. By doing so, the assembled battery 1 is heated.

  FIG. 2 shows the arrangement of the battery module 2 alone, the battery case 5 and the heat conduction board 6 in the assembled battery 1 described above.

  It is important that the lower surface of the battery module 2 and the inner surface of the bottom wall of the battery case 5 are in contact with each other thermally, and therefore, there is a gap between the lower surface of the battery module 2 and the inner surface of the bottom wall of the battery case 5. An appropriate gel-like heat conductive material 7 having adhesiveness is interposed at a required thickness.

  In addition, it is important that the bottom wall lower surface (outer surface) of the battery case 5 and the upper surface of the heat conducting board 6 are also in contact with each other in the same manner, and the heat conducting material 7 similar to the above is required between them. It is inserted in the thickness of.

  The battery module 2 includes a cell unit 21 configured by vertically stacking a plurality of flat cells 22 in a thin module case 23 made of a metal having a light weight and good thermal conductivity such as aluminum or aluminum alloy. It is housed and configured.

  The module case 23 is configured to be in close contact with the stacking direction in order to stack and bundle a plurality of cells 22. Therefore, the insulator 24 is interposed over almost the entire area between the outermost side surface of the cells 22, that is, between the end surface of the cell unit 21 in the cell stacking direction and the side surface of the module case 23 corresponding thereto. Thus, the required dielectric constant is set between the two.

  Here, since each of the plurality of cells 22 constituting the cell unit 21 expands in the thickness direction due to heat generation, the cell unit 21 is provided between the end surface of the cell unit 21 and the side surface of the module case 23 corresponding thereto. It is necessary to secure 22 swelling spaces.

  Therefore, the end surface of the cell unit 21 and the side surface of the module case 23 corresponding to the cell unit 21 are formed as a gap δ in which the central portion is in contact with each other through the insulator 24 and the surfaces are separated from each other. ing.

  This is because, for example, the module case 23 is formed wider than the dimension of the cell unit 21 in the cell stacking direction, and the cell unit 21 is accommodated in the case, and the case central portion is pressure-molded inward. As described above, the surfaces of the central portion are in contact with each other, and a space δ having a required dimension can be provided around the surfaces.

  Then, in this gap δ, the gap δ on the side close to the above-described heat conduction board 6, that is, in this embodiment, the gap δ on the lower side of the battery module 2 shown in FIG. 25 is interposed.

  In the example shown in FIG. 2, the lower end portion of the insulator 24 is cut to a required length, and a heat transfer sheet 25 is interposed in the notch, and the heat transfer sheet 25 directly becomes the end face of the cell unit 21. The side surface of the outermost cell 22 and the side surface of the module case 23 are brought into direct contact with each other so as to improve the heat transfer performance between both surfaces.

  The heat transfer sheet 25 is formed of a flexible material that can be compressed and deformed by the gap δ. When the cell 22 expands, the cell 22 is compressed and deformed by the expansion pressure, thereby securing a swollen space of the cell 22. Yes.

  The heat transfer sheet 25 is formed of a material having electrical characteristics that can compensate for the insulation performance of the portion where the insulator 24 is cut off. That is, since a good insulating performance is required even at the cut portion of the insulator 24, the heat transfer sheet 25 is selectively made of the above-described material having flexibility and insulation. A material having a relative dielectric constant capable of obtaining a coefficient is selectively used.

  Further, the heat transfer sheet 25 is a material having a thermal conductivity capable of obtaining a module thermal resistance of a predetermined value or less in a heat transfer path from the cell unit 21 to the heat conduction board 6 in addition to such flexibility and insulation. Is used for selection.

  According to the structure of the first embodiment, the heat transfer path from the cell unit 21 to the heat conduction board 6 is shortened due to the presence of the heat transfer sheet 25, so that the temperature control of the battery module 2 and the assembled battery 1 is possible. The performance can be improved.

  On the other hand, in the end surface of the cell unit 21, there is a gap δ between the side surface of the module case 23 around the portion that is in contact with the side surface of the module case 23 at the center portion. As shown, when the cell 22 expands in the stacking direction, the gap δ can be used as the expansion space of the cell 22.

  Thereby, coexistence with the ensuring of the swelling space of the cell 22 and the improvement of temperature control performance is realizable.

  In particular, in the present embodiment, the heat transfer sheet 25 has a required flexibility that allows compression deformation in the gap δ. Therefore, even in the lower gap δ filled with the heat transfer sheet 25, this heat transfer sheet By compressing and deforming 25, the expansion space of the cell 22 can be secured, and the security can be kept high.

  Further, the heat transfer sheet 25 is formed by using a material having a relative permittivity that can obtain a required dielectric constant even in a portion where the lower end portion of the insulator 24 is cut off. Since the electrical characteristics are such that the insulation performance can be compensated for, the insulation performance does not deteriorate slightly, and the quality and reliability can be improved.

  Moreover, since the heat transfer sheet 25 is set to have a heat conductivity that provides a module thermal resistance equal to or less than a predetermined value in the heat transfer path from the cell unit 21 to the heat transfer board 6, the interposed portion of the heat transfer sheet 25 Even in this case, the temperature difference of the heat transfer path can be reduced, and the battery module 2 can be cooled or heated satisfactorily.

  FIG. 4 shows a second embodiment of the present invention. In this embodiment, a porous body 24A provided with a large number of perforations by punching is used as the insulator 24 in the first embodiment.

  According to the structure of the second embodiment, in addition to the effects of the first embodiment, by making the insulator 24 into the porous body 24A, the air layer is retained in the perforated portion, so that the apparent relative dielectric constant is reduced. It can be made smaller and the choice of insulating material can be expanded when obtaining the same dielectric constant.

  Further, by using the porous body 24A, it is possible to minimize the deterioration of the compression performance and to achieve good matching with the insulation performance.

  5 and 6 show a third embodiment of the present invention. In this embodiment, a sheet 26 is interposed between the porous body 24A and the end surface of the cell unit 21 in the second embodiment. It is.

  As the sheet 26, a sheet having a large thermal conductivity in the surface direction, such as an aluminum sheet or a graphite sheet, is used. The sheet 26 extends to the portion where the heat transfer sheet 25 is disposed.

  Moreover, in this embodiment, the film 27 is stuck on the side of the porous body 24A opposite to the side on which the sheet 26 is disposed to block the opening of the porous body 24A.

  According to the structure of the third embodiment, in addition to the effects of the second embodiment, the porous body 24A has a property of being strong against compression but weak against bending. The rigidity in the direction can be ensured, and damage to the laminate layer on the surface of the cell 22 can be prevented, so that the quality can be improved.

  Further, since the sheet 26 extends so as to cover the portion where the heat transfer sheet 25 is disposed, damage to the laminate layer on the surface of the cell 22 due to the edge of the lower end of the heat transfer sheet 25 can be avoided.

  Moreover, since the sheet 26 is made of a material having a high thermal conductivity, the temperature control performance of the battery module 2 can be enhanced by the thermal diffusion effect of the sheet 26.

  Here, if the side opposite to the side where the sheet 26 of the porous body 24 </ b> A is left open, the inside of the opening will be condensed and cause corrosion, but the film 27 will block the opening and cause condensation. It is possible to avoid inducing a defect caused by.

  In each of the above embodiments, the heat transfer sheet 25 is disposed in the lower gap δ of the battery module 2 close to the heat conduction board 6, but the heat transfer sheet 25 is also provided in the upper gap δ far from the heat conduction board 6. May be provided.

  In this case, since the air heat dissipation action is enhanced on the upper end side of the battery module 2, the cooling performance when the battery module 2 is cooled can be enhanced.

DESCRIPTION OF SYMBOLS 1 ... Battery assembly 2 ... Battery module 5 ... Battery case 6 ... Heat conduction board (temperature control means)
21 ... cell unit 22 ... cell 23 ... module case 24 ... insulator 24A ... porous body 25 ... heat transfer sheet (heat conductor)
26 ... sheet 27 ... film δ ... gap

Claims (9)

A battery module including a cell unit in which a plurality of flat cells are stacked, and a module case storing the cell unit;
Temperature control means for heating or cooling the module case from its peripheral side, and
The end surface of the cell unit in the cell stacking direction and the side surface of the module case corresponding to the end surface are in contact with each other through an insulator, and the periphery is formed as a space where the surfaces are separated from each other.
A heat transfer structure for a battery module, characterized in that at least the gap on the side close to the temperature control means is filled and a heat conductive material is interposed.   2. The battery module heat transfer structure according to claim 1, wherein the heat conducting material has flexibility that allows compression deformation in the gap.   The insulator has a portion corresponding to the region where the heat conducting material is disposed, and the heat conducting material has electrical characteristics that can compensate for the insulating performance of the portion from which the insulator is cut. The heat transfer structure for a battery module according to claim 1 or 2.   4. The heat conduction material according to claim 1, wherein the heat conductivity is set to a thermal conductivity that provides a module thermal resistance of a predetermined value or less in a heat transfer path from the cell unit to the temperature control means. The heat transfer structure of the battery module as described in one.   The heat transfer structure for a battery module according to any one of claims 1 to 4, wherein the insulator is a porous body.   The heat transfer structure for a battery module according to claim 5, wherein a sheet is interposed between the insulator and an end surface of the cell unit.   The heat transfer structure for a battery module according to claim 6, wherein the sheet is made of a material having a high thermal conductivity.   The battery according to any one of claims 5 to 7, wherein a film is attached to a side surface of the insulator opposite to the side on which the sheet is disposed to block the opening of the porous body. Module heat transfer structure.   The heat transfer structure for a battery module according to any one of claims 1 to 8, wherein the heat conductive material is also filled in the gap on the side far from the temperature control means.

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