JP2010211952A - Battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery module capable of achieving high-precision temperature detection of cells while maintaining mechanical strength of the module. <P>SOLUTION: This battery module has a plurality of laminated cells 110, a case 130 containing the cells, a support plate 100 having thermal conductivity, one portion 100a of which is brought into contact with the cell and the other portion 100b of which is fixed to the case, and a temperature detecting means 120 to detect the temperature of the support plate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a battery module, and more particularly to a battery module capable of detecting the temperature of a cell.

  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, there is a great expectation for reducing carbon dioxide emissions by introducing electric vehicles (EV) and hybrid electric vehicles (HEV), and the development of secondary batteries for motor drive that holds the key to commercialization of these is thriving. Has been done.

  Generally, as a secondary battery for driving a motor, a battery module in which a plurality of flat cells connected in series are stacked and accommodated in a case is used.

  Each cell in the battery module generates heat by repeatedly charging and discharging. Therefore, the life and performance may be deteriorated when the cell reaches a certain temperature or higher.

  Therefore, conventionally, the temperature of the stacked cells is detected by interposing a heat conductive sheet between the stacked cells, extending a part of the sheet to the outside of the case, and detecting the temperature of the part. (Patent Document 1).

JP 2006-250734 A

  However, although the above-described conventional technology adds a heat conductive sheet as a component of the battery module, reinforcement of the case strength has not been studied. Therefore, since the number of stacked secondary battery cells is limited by the rigidity of the case, the conventional technique may further limit the number of stacked secondary battery cells.

  Further, in the prior art, in order to obtain temperature detection accuracy, the heat conductive sheet is stretched out of the case. For this reason, the shape of the case becomes complicated, and workability may be reduced when the parts are assembled.

  In order to solve the above problems, a battery module according to the present invention includes a plurality of stacked cells, a case, a support plate, and temperature detection means. The case accommodates a plurality of cells. The support plate has thermal conductivity, one part is in contact with the cell, and the other part is fixed to the case. The temperature detection means detects the temperature of the support plate.

  According to the battery module of the present invention, one part of the support plate is brought into contact with the cell and the other part is fixed to the case, thereby maintaining the mechanical strength of the module and eliminating the limit on the number of stacked cells. Can do.

  Moreover, since the temperature of the location near the heat source can be detected by detecting the temperature of the support plate in the battery module, the temperature of the cell can be detected with high accuracy.

  Further, by eliminating the need to extend the conductor to the outside of the case, it is possible to avoid complication of the case and prevent deterioration of workability for assembling the parts.

It is a perspective view which decomposes | disassembles and shows the battery module which concerns on embodiment of this invention. It is a front view which decomposes | disassembles and shows the battery module which concerns on embodiment of this invention. It is a perspective view which shows a cell. It is sectional drawing of the part which fixed the support plate and the lower case. It is sectional drawing of the part which made the thermistor contact | abut to a support plate and was fixed to the lower case.

  Hereinafter, the battery module according to the present invention will be described in detail with reference to embodiments. Hereinafter, a battery module of a bipolar lithium ion secondary battery (hereinafter referred to as “stacked battery”) will be described as an example of the battery module, but the present invention is not limited thereto. In the drawings to be referred to below, the shape, thickness and the like of each element of the battery module are exaggerated for the sake of easy understanding of the invention.

  As shown in FIGS. 1 and 2, the battery module 10 according to this embodiment includes a cell (unit cell) 110, a support plate 100, a thermistor 120, and a case 130. 1 and 2 also show other components (parts and the like) of the battery module 10, but the description of these components will be omitted.

  The cell 110 forms a cell unit by inserting and laminating spacers (insulating material) between the electrodes and connecting them in series. The cell unit is housed in a case 130 including a lower case 131 and an upper case 132. At this time, the cell 110 is aligned by the sleeve. The sleeve functions as a reinforcing member for the battery module 10. In FIG. 1 and FIG. 2, four cells 110 are stored, but the number of cells is not limited.

  As shown in FIG. 3, the cell 110 of the stacked battery has, for example, a rectangular flat shape, and a positive electrode tab 310 </ b> A and a negative electrode tab 310 </ b> B for taking out electric power from both sides thereof are drawn out. The power generation element 320 is wrapped with an exterior material (for example, a laminate film) 330, and the periphery thereof is heat-sealed, and is sealed with the positive electrode tab 310A and the negative electrode tab 310B pulled out.

  As shown in FIGS. 1 and 2, the support plate 100 includes a bottom surface portion 100a, a short side surface portion 100b, and a long side surface portion 100c. The long side surface portion 100c of the support plate 100 has an uneven shape composed of a convex portion 101c and a concave portion 102c. However, the support plate 100 is not limited thereto, and the long side surface portion 100c may not have the convex portion 101c and the concave portion 102c. The support plate 100 has thermal conductivity. The support plate 100 is preferably made of a material having a lower thermal resistance. For example, it can be made of aluminum or copper.

  The bottom surface portion 100 a of the support plate 100 is inserted between any stacked surfaces of the cells 110. Thereby, the bottom surface portion 100 a of the support plate 100 is brought into contact with the cell 110. The place where the temperature is higher in the battery module 10 is between the stacked surfaces of the cells 110 that are the heat generation sources. By inserting the bottom surface portion 100a of the support plate 100 between the stacked surfaces of the cells 110 and detecting the temperature of the support plate 100, it is possible to detect the temperature between the cells 110 at a higher temperature. That is, the temperature detection accuracy of the cell 110 can be improved.

  The number of support plates 100 is not limited. That is, the number of support plates 100 can be appropriately selected according to the number of stacked cells 110 and the required mechanical strength of the battery module 10. Further, the position between the stacked surfaces of the cells 110 into which the bottom surface portion 100a of the support plate 100 is inserted is not limited. For example, it may be a position where the mechanical strength of the battery module 10 is most improved, or may be a position where the heat dissipation of the heat generated by the cells 110 is the best.

  As will be described later, since the support plate 100 is brought into contact with the lower case 131, the heat between the cells 110, which has a higher temperature in the battery module 10, is efficiently transferred from the lower case 131 via the support plate 100 serving as a new heat dissipation route. Can dissipate heat. Thereby, the heat dissipation of the battery module 10 can be improved.

  The support plate 100 has such a size that the short side surface portion 100b and the convex portion 101c of the long side surface portion 100c come into contact with the lower case 131 when inserted between the stacked surfaces of the cells 110. However, the size of the support plate 100 may be smaller than the size of the support plate 100 shown in FIG. 1, and may be, for example, half the size of the support plate 100 shown in FIG. The outer periphery of the support plate 100 is bent to provide the short side surface portion 100b and the long side surface portion 100c, and the support plate 100 and the inner side of the lower case 131 are brought into contact with each other to effectively use the heat transfer characteristics of the support plate 100. The heat dissipation of 110 can be promoted. Thereby, deterioration of the cell by high temperature, ie, the capacity | capacitance fall of a cell, can be suppressed. This makes it possible to reduce the margin for capacity reduction, and thus to realize a volume reduction of the battery module.

  Here, the short side surface portion 100b of the support plate 100 and the lower case 220 are fixed in contact with each other. The fixing may be performed by screwing. Furthermore, the convex part 101c of the long side surface part 100c of the support plate 100 (any position of the long side surface part 100c when the convex part 101c is not provided) and the lower case 220 are screwed to the long side part 100c and the lower case 220. It is desirable to fix to the state which contacted. Thereby, the mechanical strength (for example, rigidity) of a module can be maintained and the restriction | limiting of the number of lamination | stacking of a cell can be eliminated.

  The thermistor 120 is fixed to the lower case 131 so as to come into contact with the concave portion 102c of the support plate 100 (any position of the long side surface portion 100c when the convex portion 101c is not provided) when the battery module 10 is assembled. As will be described later, the fixing may be performed by fixing the thermistor 120 to the tip of the clip and fixing the clip to the lower case 131 using a hole 131a provided in the lower case 131.

  By disposing the thermistor 120 in the recess 102 c provided in the long side surface portion 100 c of the support plate 100, the thermistor 120 can be installed inside the battery module 10. Since it is not necessary to provide the thermistor 120 outside the battery module 10, it is not necessary to extend the support plate 100 to the outside of the case. Therefore, the shape of the case does not become complicated, and it is possible to prevent a reduction in workability for assembling the parts.

  When the concave portion 102 c is not provided in the long side surface portion 100 c of the support plate 100, the thermistor 120 may be brought into contact with the long side surface portion 100 c of the support plate 100 by arranging the thermistor 120 in a hole provided in the lower case 131, for example. . Alternatively, the thermistor 120 may be brought into contact with the lower case 131 and the temperature of the support plate 100 may be detected via the lower case 131.

  It is desirable to provide a plurality of recesses 102c on the support plate. Thereby, since the freedom degree of the setting position of the thermistor 120 increases, it can respond also to the case where a some cooling means is used, and can respond easily to the flow direction of various refrigerant | coolants.

  FIG. 4 is a cross-sectional view of a portion where the support plate 100 and the lower case 131 are fixed. In FIG. 4, illustration of the detailed part of battery modules, such as the inside of the cell 110, is abbreviate | omitted for simplicity.

  As shown in FIG. 4, a screw hole is made in the convex portion 101 c of the support plate and the lower case 131, and the convex portion 101 c of the support plate and the lower case 131 are fixed with a bolt 400 and a nut 410. By fixing the convex portion 101c of the support plate 100 and the lower case 131, the strength of the module can be maintained even when the number of stacked cells 110 is increased.

  The heat generated in the cell 110 is transferred from the bottom surface portion 100a of the support plate 100 in contact with the cell 110 to the short side surface portion 100b and the long side surface portion 100c of the support plate 100 in contact with the lower case 120 via the support plate 100. It is transmitted. Then, heat is radiated from the lower case 220 in contact with the short side surface portion 100b and the long side surface portion 100c of the support plate 100.

  As described above, in order to bring the support plate 100 into contact with the lower case 131, the heat between the cells 110, which becomes higher in the battery module 10, can be efficiently radiated through the support plate 100 serving as a new heat dissipation route. Can do. Thereby, the heat dissipation of the battery module 10 can be improved.

  Further, the outer periphery of the support plate 100 is bent to provide the short side surface portion 100b and the long side surface portion 100c, and the support plate 100 and the inner side of the lower case 131 are brought into contact with each other to effectively use the heat transfer characteristics of the support plate 100. The heat dissipation of the cell 110 can be promoted.

  Thus, in the present embodiment, the bottom surface portion is brought into contact with the cell 110, and the convex portions 101c of the short side surface portion 100b and the long side surface portion 100c are brought into contact with the lower case 120 to dissipate heat. Therefore, it is not necessary to heat the heat transfer body inserted between the cells 110 by extending it to the outside of the case. Therefore, it is possible to avoid complication of the case due to extending the heat transfer body to the outside of the case, and to prevent deterioration in workability of assembling the parts.

  FIG. 5 is a cross-sectional view of a portion where the thermistor 120 is brought into contact with the support plate 100 and fixed to the lower case 131. In FIG. 5, for the sake of simplicity, the detailed portion of the battery module such as the inside of the cell 110 is not shown.

  As shown in FIG. 5, the thermistor 120 is fixed to the lower case 131 so that when the battery module 10 is assembled, the thermistor 120 comes into contact with the recess 102 c provided in the support plate 100. The thermistor 120 may be fixed to the lower case 131 by fixing the thermistor 120 to the tip of the clip 500 and fixing the clip 500 using the hole 131 a provided in the lower case 131.

  By disposing the thermistor 120 in the recess 102 c provided in the long side surface portion 100 c of the support plate 100, the thermistor 120 can be installed inside the battery module 10. Since it is not necessary to provide the thermistor 120 outside the battery module 10, it is not necessary to extend the support plate 100 to the outside of the case. Therefore, the shape of the case does not become complicated, and it is possible to prevent a reduction in workability for assembling the parts.

  Further, in the present embodiment, the bottom surface portion 100a of the support plate 100 is interposed between the cells 110 that have a higher temperature inside the battery module 10, and is supported by the thermistor 120 that is in contact with the long side surface portion 100c of the support plate 100. The temperature of the plate 100 is detected. Thereby, the temperature detection accuracy can be improved because the thermistor 120 detects the temperature of the higher temperature inside the battery module 10. Moreover, the temperature margin at the time of controlling the temperature of a battery module can be reduced because temperature detection accuracy improves.

  Moreover, since the thermistor 120 is installed inside the battery module 10, an increase in the volume of the battery module 10 due to the installation of the thermostat 120 can be suppressed.

  Next, in order to verify the temperature detection accuracy of the battery module according to the present embodiment, experimental results by simulation are shown.

<Experimental result>
1. Method Based on the data of the shape of the battery module, the physical properties of the component materials, the amount of heat generated from the cells, and the external environment (wind speed), the temperature distribution of the battery module was simulated by a computer.
2. Conditions The amount of heat generated per cell was 5 W, the wind speed was 0.5 m / s, and the difference between the maximum temperature in the battery module and the temperature of the thermistor arrangement (hereinafter referred to as “temperature detection accuracy”) was simulated.
3. Subject A. Comparative example (conventional example)
A conventional battery module in which a thermistor is disposed outside the battery module (abutting on the outer surface of the lower case) without using a support plate.
B. Example 1 of the present invention
A battery module in which the bottom surface of the support plate is interposed between the cells, the short side surface portion is fixed to the lower case, and the thermistor is in contact with the convex portion of the long side surface portion of the battery module.
C. Embodiment 2 of the present invention
A battery module in which the bottom surface of the support plate is interposed between the cells, the short side surface portion is fixed to the lower case, and the thermistor is in contact with the concave portion of the long side surface portion of the battery module.
4). Results The temperature detection accuracy of the comparative example was 5.63 ° C. On the other hand, the temperature detection accuracy of Example 1 of the present invention was 2.76 ° C., and the temperature detection accuracy of Example 2 of the present invention was 1.12 ° C.

  By this experiment, the effect of the temperature detection accuracy improvement by this embodiment was proved. In addition, from the results of Example 1 of the present invention, it was proved that there is a sufficient improvement in temperature detection accuracy even if the temperature of the support plate is detected using a support plate that does not have a recess in the long side surface portion. Furthermore, from the results of Example 2 of the present invention, it was proved that the temperature detection accuracy was further improved by detecting the temperature of the recess using a support plate having a recess on the long side surface.

  Although the battery module according to the present embodiment has been described above, the bottom surface portion of the present embodiment corresponds to one part of the present invention. The short side surface portion corresponds to the other portion and the contact surface, and the long side surface portion corresponds to the other portion and the contact surface. A convex part is corresponded to another part and a contact surface. The thermistor corresponds to temperature detection means.

Below, the effect of the battery module which concerns on embodiment of this invention is shown.
-One part of the support plate is brought into contact with the cell and the other part is fixed to the case, so that the mechanical strength of the module can be maintained and the limit of the number of stacked cells can be eliminated.
-By detecting the temperature of the support plate in the battery module, the temperature near the heat source can be detected, so that the cell temperature can be detected with high accuracy.
-By eliminating the need to extend the conductor to the outside of the case, it is possible to avoid complication of the case and prevent deterioration in workability for assembling the parts.
-By inserting a support plate between cells and detecting the temperature of the support plate, it is possible to detect the temperature of the higher-temperature part in the module, so that the temperature detection accuracy can be improved.
-By making the side surface portion of the support plate whose bottom surface portion is in contact with the cell and the inside of the lower case abut on the surface, the heat transfer characteristics of the support plate can be effectively used and the heat radiation of the cell can be promoted. This makes it possible to reduce the margin for a decrease in battery capacity, thereby realizing a reduction in the volume of the battery module.
-By disposing the thermistor in the concave portion provided on the contact surface of the support plate with the lower case, it is not necessary to install the thermistor outside the battery module, so that an increase in the volume of the battery module due to the thermistor installation can be suppressed.

10 battery module,
100 support plate,
100a bottom part (one part),
100b short side surface (other part, contact surface),
100c long side surface part (other part, contact surface),
101c Convex part (other part, contact surface),
102c recess,
110 cells,
120 thermistor (temperature detection means),
130 cases,
131 Lower case,
132 Upper case,
500 clips.

Claims (4)

A plurality of stacked cells;
A case containing the plurality of cells;
One part is in contact with the cell, and the other part is a support plate having thermal conductivity fixed to the case;
Temperature detecting means for detecting the temperature of the support plate;
A battery module comprising:   2. The battery module according to claim 1, wherein the one portion of the support plate is interposed between the cells and is in contact with the cells.   The battery module according to claim 1, wherein the other portion of the support plate has a contact surface that contacts an inner wall of the case, and is fixed to the case by the contact surface. .   The battery module according to claim 3, wherein the contact surface is provided with a recess that does not contact the inner wall of the case, and the temperature detecting means is provided in the recess.

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