JP2016035876A - Battery module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery module that can prevent an expanding electric cell from being excessively pushed.SOLUTION: A battery module 100 has electric cells 10 and a housing 20. The electric cell is formed by laminating a positive electrode and a negative electrode through a separator to form a power generation element and sealing the power generation element with an exterior coating. The electric cells are accommodated in the housing 20 (a housing case 21 and a lid 22) while pressed. The housing has a press portion (at least any one of a first press portion 21a and a second press portion 22a) and a deformation absorbing portion (at least any one of a first displacement absorbing portion 21b and a second displacement absorbing portion 22b). The press portion presses the electric cells inwards from at least one side in the lamination direction Z of the electrodes. The deformation absorbing portion is formed integrally with the press portion, and absorbs deformations of the press portion when the press portion is pressed outwards by the expanding electric cells.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a battery module.

  Conventionally, there is a single cell in which a power generation element is sealed with an exterior material. There is a battery module in which a plurality of such single cells are stacked and housed in a casing. The unit cell may expand due to generation of gas in the power generation element with charge / discharge. If the gas stays inside the power generation element, the performance of the unit cell is degraded. Then, the structure which presses the part of the electric power generation element of a single cell with a housing and discharges gas from an electric power generation element is disclosed (refer patent document 1).

JP 2008-59941 A

  By the way, if the power generation element is strongly pressed, the gas can be efficiently discharged from the inside of the power generation element to the peripheral portion. On the other hand, when the power generation element is excessively pressed, there is a possibility that a malfunction such as an internal short circuit may occur in the power generation element. For this reason, there is a demand for a technique that can maintain battery characteristics without excessively pressing the expanding unit cell.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a battery module that can prevent excessive expansion of a unit cell that expands.

  The battery module according to the present invention that achieves the above object includes a unit cell and a casing. The unit cell is formed by sealing a power generation element formed by laminating a positive electrode and a negative electrode with a separator interposed between them. The casing accommodates the unit cell in a pressed state. Here, the housing includes a pressing portion and a deformation absorbing portion. The pressing portion presses the unit cell inward from at least one side in the stacking direction of the electrodes. The deformation absorbing portion is formed integrally with the pressing portion, and absorbs deformation of the pressing portion when the pressing portion is pressed outward by the expanded unit cell.

  In the battery module of the present invention, the deformation absorbing portion absorbs the deformation of the pressing portion when the pressing portion is pressed outward by the unit cell expanded. That is, the pressing portion can be retracted outward using the displacement absorbing portion in accordance with the expansion of the unit cell while pressing the unit cell inward. Therefore, the battery module can prevent excessively pressing the expanding cell. In this way, the battery module can maintain battery characteristics.

It is a perspective view which shows the battery module which concerns on 1st Embodiment. It is a disassembled perspective view which decomposes | disassembles and shows the battery module of FIG. 1 to each structural member. It is a side view which shows the principal part of the battery module of FIG. 1 partially in a cross section along line 3-3. FIG. 4 is a partial cross-sectional view showing the unit cell of FIG. It is a side view which shows the battery module which concerns on 2nd Embodiment partially in a cross section. It is a side view which shows the battery module which concerns on 3rd Embodiment partially in a cross section.

  Embodiments according to the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The sizes and ratios of the members in the drawings are exaggerated for convenience of explanation and may be different from the actual sizes and ratios. In all the drawings of FIGS. 1 to 6, the azimuth is indicated by using arrows represented by X, Y, and Z. The direction of the arrow represented by X indicates the longitudinal direction X of the unit cell 10. The direction of the arrow represented by Y indicates the short direction Y of the unit cell 10. The direction of the arrow represented by Z indicates the stacking direction Z of the electrodes (positive electrode 11 and negative electrode) of the unit cell 10.

(First embodiment)
The battery module 100 is configured by housing a plurality of single cells 10 in a housing 20. The battery module 100 is disposed in, for example, an electric vehicle or a hybrid vehicle, and supplies power to a motor provided in the vehicle.

  The battery module 100 will be described with reference to FIGS.

  FIG. 1 is a perspective view showing the battery module 100. FIG. 2 is an exploded perspective view showing the battery module 100 of FIG. FIG. 3 is a side view partially showing a cross section of the main part of the battery module 100 of FIG. 1 along line 3-3. In FIG. 3, an example of the deformation | transformation absorption part after a deformation | transformation is shown with the broken line. FIG. 4 is a partial cross-sectional view showing the unit cell 10 of FIG.

  The battery module 100 includes a single battery 10 and a housing 20. Hereinafter, each component of the battery module 100 will be described in order.

  The cell 10 is shown in FIGS. 1-4 and charges / discharges electric power.

  The unit cell 10 includes a power generation element and an exterior body (laminate sheet 14). The power generation element is formed by laminating a positive electrode 11 and a negative electrode 12 with a separator 13 interposed therebetween. The laminate sheet 14 seals the power generation element. Hereinafter, the positive electrode 11, the negative electrode 12, the separator 13, and the laminate sheet 14 that constitute the unit cell 10 will be described in order.

  As shown in FIG. 4, the positive electrode 11 is configured by binding a positive electrode active material 11 b to both surfaces of a positive electrode current collector 11 a having conductivity and formed in a plate shape. As shown in FIG. 1 and the like, the positive electrode terminal 11c for taking out electric power is formed to extend in a longitudinal direction X from a part of one end of the positive electrode current collector 11a. The plurality of positive electrode terminals 11c of the positive electrode 11 stacked together are fixed to each other by welding or adhesion.

As the material of the positive electrode current collector 11a, for example, an aluminum expanded metal, an aluminum mesh, or an aluminum punched metal is used. The material of the positive electrode active material 11b includes various oxides (lithium manganese oxide such as LiMn ₂ O ₄ ; manganese dioxide; lithium nickel oxide such as LiNiO ₂ ; lithium cobalt oxide such as LiCoO ₂ ; lithium Containing nickel cobalt oxide; amorphous vanadium pentoxide containing lithium) or chalcogen compound (titanium disulfide or molybdenum disulfide).

  As shown in FIG. 4, the negative electrode 12 is configured by binding a negative electrode active material 12 b to both surfaces of a negative electrode current collector 12 a that is conductive and formed in a plate shape. As shown in FIG. 1 and the like, the negative electrode terminal 12c is formed to extend in the longitudinal direction X from a part of one end of the negative electrode current collector 12a so as not to overlap with the positive electrode terminal 11c of the positive electrode 11. . The length of the negative electrode 12 in the longitudinal direction X is longer than the length of the positive electrode 11 in the longitudinal direction X. The length of the negative electrode 12 in the short direction Y is the same as the length of the positive electrode 11 in the short direction Y. A plurality of negative electrode terminals 12c of the negative electrode 12 stacked on each other are fixed to each other by welding or adhesion.

  As the material of the negative electrode current collector 12a, for example, a copper expanded metal, a copper mesh, or a copper punched metal is used. As the material of the negative electrode active material 12b, a carbon material that absorbs and releases lithium ions is used. For such carbon materials, for example, natural graphite, artificial graphite, carbon black, activated carbon, carbon fiber, coke, or organic precursors (phenol resin, polyacrylonitrile, or cellulose) are heat-treated in an inert atmosphere and synthesized. Carbon is used.

  The separator 13 electrically isolates the positive electrode 11 and the negative electrode 12. As shown in FIG. 4, the separator 13 is formed in a rectangular shape and disposed between the positive electrode 11 and the negative electrode 12. The length in the longitudinal direction X of the separator 13 is longer than the length in the longitudinal direction X of the positive electrode 11 excluding the portion of the positive electrode terminal 11c. The separator 13 holds an electrolytic solution between the positive electrode 11 and the negative electrode 12 to ensure ion conductivity.

  For example, polypropylene is used as the material of the separator 13. Polypropylene is impregnated with a non-aqueous electrolyte prepared by dissolving an electrolyte in a non-aqueous solvent. In order to hold the non-aqueous electrolyte, a polymer is included.

  As shown in FIG. 3, the laminate sheet 14 covers and seals the power generating element from both sides along the stacking direction Z. The laminate sheet 14 is composed of a rectangular sheet in which a metal plate is embedded. When the power generation element is sealed with the laminate sheet 14, a part of the periphery of the laminate sheet 14 is opened, and the other periphery is sealed by heat welding. Next, an electrolytic solution is injected into the laminate sheet 14 from the open portion, and the separator 13 is impregnated with the electrolytic solution. Finally, the inside of the laminate sheet 14 is decompressed to release air from the open portion, and the open portion is heat-sealed to completely seal it.

  As the material of the laminate sheet 14, for example, three kinds of materials stacked on each other are used. Specifically, for example, polyethylene (PE), ionomer, or ethylene vinyl acetate (EVA) is used as the material of the first layer of the heat-fusible resin adjacent to the negative electrode 12. For the second layer metal foil, for example, an Al foil or a Ni foil is used. For example, rigid polyethylene terephthalate (PET) or nylon is used for the third layer resin film.

  The housing 20 (the housing case 21 and the lid 22) is shown in FIGS. 1 to 4 and houses the unit cell 10 in a pressed state.

  The housing 20 (the housing case 21 and the lid 22) includes a pressing portion (at least one of the first pressing portion 21a and the second pressing portion 22a) and a deformation absorbing portion (at least the first displacement absorbing portion 21b and the second displacement absorbing portion). 22b). The pressing portion presses the unit cell 10 inward from at least one side in the stacking direction Z of the electrodes (the positive electrode 11 and the negative electrode 12). The deformation absorbing portion (at least one of the first displacement absorbing portion 21b and the second displacement absorbing portion 22b) is formed integrally with the pressing portion, and when the pressing portion is pressed outward by the expanded unit cell 10. Absorbs deformation of the pressing part. Hereinafter, the housing case 21 and the lid 22 constituting the housing 20 will be described in order.

  The housing case 21 houses a plurality of unit cells 10 stacked in the stacking direction Z so as to be placed inside. The housing case 21 opens, for example, upward along the stacking direction Z. The housing case 21 includes a first pressing portion 21 a that presses the unit cell 10 at a central portion thereof. The housing case 21 includes a first displacement absorbing portion 21b at the outer peripheral portion of the central portion thereof. The position of the 1st displacement absorption part 21b is not specifically limited. The first displacement absorbing portion 21b is displaced so as to reduce the deformation amount of the first pressing portion 21a. The housing case 21 integrally forms a first pressing portion 21a and a first displacement absorbing portion 21b. The first pressing portion 21a is formed in a step difference along the stacking direction Z with the first displacement absorbing portion 21b. The first pressing portion 21a is formed so as to protrude upward along the stacking direction Z from the first displacement absorbing portion 21b. The first pressing portion 21a may be formed in a flat plate shape or a curved plate shape.

  The lid 22 covers the housing case 21 that houses the plurality of single cells 10. The lid 22 opens, for example, below in the stacking direction Z. The lid 22 has its side surface overlapped with part of the side surface of the housing case 21. The lid 22 is joined to the housing case 21 by welding, for example, in a state where the plurality of unit cells 10 are pressed. The lid 22 has the same configuration as the housing case 21. The lid | cover 22 is equipped with the 2nd press part 22a which presses the cell 10 in the center part. The lid | cover 22 is equipped with the 2nd displacement absorption part 22b in the outer peripheral part of the center part. The position of the second displacement absorbing portion 22b is not particularly limited. The second displacement absorbing portion 22b is displaced so as to reduce the deformation amount of the second pressing portion 22a. The lid 22 integrally forms a second pressing portion 22a and a second displacement absorbing portion 22b. The second pressing portion 22a is formed in a step difference along the stacking direction Z with the second displacement absorbing portion 22b. The second pressing portion 22a is formed so as to protrude downward along the stacking direction Z from the second displacement absorbing portion 22b. The second pressing portion 22a may be formed in a flat plate shape or a curved plate shape.

  Here, referring to Table 1, the experimental results relating to the suppression of the pressure increase of the unit cell 10 of the battery module 100 according to the first embodiment will be described in comparison with the battery modules of Comparative Examples 1-3. The experimental results according to the second embodiment and the third embodiment described in Table 1 will be described later.

  In the experiment, a protrusion was pierced into the unit cell 10 being pressurized, and the pressure of the released gas was measured. Here, in order to accurately measure the pressure value of the gas released from the unit cell 10, the chamber when the protrusion of the unit cell 10 is stabbed in a state where the unit cell 10 is stored in a chamber having a volume of about 1000L. The pressure inside was measured. When the unit cell 10 is stabbed by a protrusion, the laminate sheet 14 is cleaved. The internal pressure of the cell 10 is defined as P. The pressure P is a differential pressure from the atmospheric pressure in the experimental environment.

  The area where the pressing portions (first pressing portion 21a and second pressing portion 22a) of the casing 20 (the housing case 21 and the lid 22) press the unit cell 10 along the stacking direction Z is defined as S. A force derived from the product of the pressure P and the area S is applied to the pressing portions (the first pressing portion 21a and the second pressing portion 22a). This force is defined as force F. The pressure when the laminate sheet 14 pierced with the protrusion is cleaved and the gas is released is defined as a pressure Pr. In particular, a force at a pressure Pr is defined as a force Fr. The initial value of the pressure P is 0 or negative pressure. Here, since the area S is constant and the pressure P varies, the force at the pressure Pr is defined as a force Fr.

  When the cell 10 expands, the pressing portions (the first pressing portion 21a and the second pressing portion 22a) are displaced outward. This displacement amount is defined as a displacement amount L. In particular, the displacement amount at the pressure Pr is defined as the displacement amount Lr. The displacement amount 1 mm and the displacement amount Lr shown in Table 1 correspond to 1 mm.

  The battery modules 1 to 3 are experiments in which the deformation amount of the unit cell 10 is intentionally suppressed by increasing the rigidity of the pressing portion of the casing (the housing case and the lid) and inhibiting the unit cell 10 from being deformed. It is an example.

  The battery module 100 of 1st Embodiment displaces a press part (the 1st press part 21a and the 2nd press part 22a) to 7 mm by a deformation | transformation absorption part (the 1st displacement absorption part 21b and the 2nd displacement absorption part 22b). I was able to. On the other hand, since the battery modules of the comparative examples 1 to 3 did not include the deformation absorbing part, the pressing part could be displaced only by 1, 3 and 5 mm. Furthermore, since the battery module 100 of 1st Embodiment was able to fully displace the press part (the 1st press part 21a and the 2nd press part 22a), the maximum value of the pressure measured in the chamber was set. It was possible to suppress to 35 kPa. On the other hand, since the battery modules of the comparative 1 to 3 could not displace the pressing part sufficiently, the maximum values of the pressures measured in the chamber were as high as 50, 50, and 48 kPa. It was. As a result, the differential value obtained by differentiating the maximum pressure value was sufficiently suppressed to 250 kPa / sec for the battery module 100 of the first embodiment, while 500, 480, and The pressure became 450 kPa / sec.

  Since the battery module 100 of the first embodiment and the battery modules 1 to 3 of the comparative example are deformed within the range of elastic deformation, when the laminate sheet 14 is cleaved, the displacement of the single cell is restored.

  According to the battery module 100 which concerns on 1st Embodiment mentioned above, there exists an effect by the following structures.

  The battery module 100 includes a single battery 10 and a housing 20 (a housing case 21 and a lid 22). The unit cell 10 is formed by sealing a power generation element formed by laminating a positive electrode 11 and a negative electrode 12 via a separator 13 with an exterior body (laminate sheet 14). The housing 20 (the housing case 21 and the lid 22) houses the unit cell 10 in a pressed state. Here, the housing 20 (the housing case 21 and the lid 22) includes a pressing portion (at least one of the first pressing portion 21a and the second pressing portion 22a) and a deformation absorbing portion (at least the first displacement absorbing portion 21b and the second pressing portion). Any one of the displacement absorbing portions 22b) is provided. The pressing portion presses the unit cell 10 inward from at least one side in the stacking direction Z of the electrodes (the positive electrode 11 and the negative electrode 12). The deformation absorbing portion (at least one of the first displacement absorbing portion 21b and the second displacement absorbing portion 22b) is formed integrally with the pressing portion, and when the pressing portion is pressed outward by the expanded unit cell 10. Absorbs deformation of the pressing part.

  According to such a configuration, when the pressing portion is pressed outward by the expanded battery 10, the deformation absorbing portion absorbs the deformation of the pressing portion. That is, the pressing portion can be retracted outward using the displacement absorbing portion in accordance with the expansion of the unit cell 10 while pressing the unit cell 10 inward. Therefore, the battery module 100 can prevent the cell 10 that expands from being excessively pressed. In this way, the battery module 100 can maintain battery characteristics.

  Further, the deformation absorbing portion (at least one of the first displacement absorbing portion 21b and the second displacement absorbing portion 22b) is more rigid than the pressing portion (at least one of the first pressing portion 21a and the second pressing portion 22a). It can be set as the structure made low.

  According to such a configuration, the deformation absorbing portion can be deformed before the pressing portion is largely deformed with the expansion of the unit cell 10. That is, the pressing portion can be retracted outward in accordance with the expansion of the unit cell 10 in a state where the deformation is within a certain range. Therefore, the battery module 100 can prevent the cell 10 that expands from being excessively pressed.

  Further, the deformation absorbing portion (at least one of the first displacement absorbing portion 21b and the second displacement absorbing portion 22b) is an outer peripheral edge of the pressing portion (at least one of the first pressing portion 21a and the second pressing portion 22a). It can be set as the structure formed in.

  According to such a configuration, the expanding unit cell 10 can be annularly pressed by the pressing portion (at least one of the first pressing portion 21a and the second pressing portion 22a). Therefore, the pressing portion can reduce the pressure per unit area applied to the laminate sheet 14 as compared with a case where only a part of the expanding unit cell 10 is pressed. Therefore, the battery module 100 can prevent the cell 10 that expands from being excessively pressed.

  Furthermore, the pressing portions (the first pressing portion 21a and the second pressing portion 22a) can be configured to press the unit cell 10 from both sides in the stacking direction Z of the electrodes (the positive electrode 11 and the negative electrode 12).

  According to such a configuration, the pressing portions (the first pressing portion 21a and the second pressing portion 22a) can press the expanding unit cell 10 over a wide area. Therefore, the pressing portion can reduce the pressure per unit area applied to the laminate sheet 14 as compared with the case where only one side of the expanding unit cell 10 is pressed. Therefore, the battery module 100 can prevent the cell 10 that expands from being excessively pressed.

  Further, a plurality of the unit cells 10 can be provided along the stacking direction Z.

  According to such a configuration, each of the plurality of unit cells 10 is moved by the pressing unit (at least one of the first pressing unit 21a and the second pressing unit 22a) via the unit cell 10 arranged on the outermost side. Excessive pressing can be prevented.

(Second Embodiment)
The battery module 200 according to the second embodiment includes notch portions (first notch portion 31b1 and second notch portion 32b1) in the deformation absorbing portion (first displacement absorbing portion 31b and second displacement absorbing portion 32b) of the casing 30. The configuration differs from the configuration of the battery module 100 according to the first embodiment described above.

  In the second embodiment, the same reference numerals are used for components having the same configuration as in the first embodiment described above, and the above description is omitted.

  The battery module 200 will be described with reference to FIG.

  FIG. 5 is a side view partially showing the battery module 200 in cross section. In FIG. 5, an example of the deformation | transformation absorption part after a deformation | transformation is shown with the broken line.

  The housing 30 includes a housing case 31 and a lid 32. The housing case 31 and the lid 32 have the same configuration as the housing case 21 and the lid 22 except for the cutout portions (the first cutout portion 31b1 and the second cutout portion 32b1).

  The housing case 31 includes a first cutout portion 31b1 with respect to the first displacement absorbing portion 31b formed on the outer peripheral edge of the first pressing portion 31a. The first cutout portion 31b1 is formed by partially reducing the cross-sectional area of the first displacement absorbing portion 31b. Specifically, the first cutout portion 31b1 is an outer side along the stacking direction Z of the first displacement absorbing portion 31b and cuts out a part of the end portion that is easily refracted as compared with other portions. Forming. The first cutout portion 31b1 may be formed inwardly along the stacking direction Z of the first displacement absorbing portion 31b, with a part of its end cutout. The first cutout portion 31b1 may be formed by cutting out a part of the flat plate portion of the first displacement absorbing portion 31b. The first cutout portion 31b1 may be formed by providing one or more holes or through holes having a predetermined depth in the first displacement absorbing portion 31b.

  The lid 32 includes a second notch 32b1 with respect to the second displacement absorbing part 32b formed on the outer peripheral edge of the second pressing part 32a. The second cutout portion 32b1 is formed by partially reducing the cross-sectional area of the second displacement absorbing portion 32b. Specifically, the second notch portion 32b1 is an outer side along the stacking direction Z of the second displacement absorbing portion 32b, and a part of the end portion that is more easily refracted than other portions is notched. Forming. Similar to the first notch 31b1, the second notch 32b1 can be embodied by various configurations.

  With reference to Table 1, an experimental result related to suppression of the pressure increase of the unit cell 10 of the battery module 200 will be described.

  The battery module 200 has a pressing portion (first pressing portion) by means of a deformation absorbing portion (first displacement absorbing portion 31b and second displacement absorbing portion 32b) having notched portions (first notch portion 31b1 and second notch portion 32b1). 31a and the second pressing part 32a) could be displaced up to 7 mm. Furthermore, since the battery module 200 was able to sufficiently displace the pressing portions (the first pressing portion 31a and the second pressing portion 32a), the maximum value of the pressure measured in the chamber is suppressed to 30 kPa. I was able to. As a result, the differential value obtained by differentiating the maximum pressure value was sufficiently suppressed to 100 kPa / sec. The unit cell 10 of the battery module 200 is plastically deformed.

  According to the battery module 200 which concerns on 2nd Embodiment mentioned above, there exists an effect by the following structures.

  In the battery module 200, the deformation absorbing portion (at least one of the first displacement absorbing portion 31b and the second displacement absorbing portion 32b) is a cutout portion (at least the first cutout portion 31b1) that is partially formed with a small cross-sectional area. And any one of the second notches 32b1).

  According to such a configuration, when the battery cell 10 is deformed, the deformation absorbing portion can be quickly deformed with reference to the notch portion that is relatively weak compared to the surroundings. That is, when the pressing portion is pressed outward by the expanded unit cell 10, the deformation absorbing portion can be quickly displaced so as to reduce the deformation amount of the pressing portion. Therefore, the battery module 200 can prevent the cell 10 that expands from being excessively pressed.

(Third embodiment)
In the battery module 300 according to the third embodiment, the configuration including the reinforcing member 40 that reinforces the deformation absorbing portion (the first displacement absorbing portion 21b and the second displacement absorbing portion 22b) of the housing 20 is the first and the second described above. Different from the configurations of the battery modules 100 and 200 according to the second embodiment.

  In the third embodiment, the same components as those in the first and second embodiments described above are denoted by the same reference numerals, and the above description is omitted.

  The battery module 300 will be described with reference to FIG.

  FIG. 6 is a side view partially showing the battery module 300 in cross section. In FIG. 6, an example of the deformation | transformation absorption part after a deformation | transformation is shown with the broken line.

  The reinforcing member 40 reinforces the deformation absorbing portion (at least one of the first displacement absorbing portion 21b and the second displacement absorbing portion 22b). The reinforcing member 40 is disposed so as to straddle both ends of the deformation absorbing portion. The reinforcing member 40 is formed in a long plate shape along the longitudinal direction X of the unit cell 10. One reinforcing member 40 is provided for each of the first displacement absorbing portions 21 b at both ends along the short direction Y of the unit cell 10. The reinforcing member 40 is made of a material whose strength or ductility is smaller than that of the exterior body (laminate sheet 14). The reinforcing member 40 is formed separately from the first displacement absorbing portion 21b and then joined to the first displacement absorbing portion 21b. The reinforcing member 40 may be formed integrally with the first displacement absorbing portion 21b.

  Similarly, one reinforcing member 40 is provided at each of the second displacement absorbing portions 22 b at both ends along the short direction Y of the unit cell 10 with respect to the lid 22. The reinforcing member 40 is formed separately from the second displacement absorbing portion 22b and then joined to the second displacement absorbing portion 22b. The reinforcing member 40 may be formed integrally with the second displacement absorbing portion 22b.

  With reference to Table 1, the experimental results relating to the suppression of the pressure increase of the unit cell 10 of the battery module 300 will be described.

  The battery module 300 displaces the pressing portions (the first pressing portion 21a and the second pressing portion 22a) to 7 mm by the deformation absorbing portion (the first displacement absorbing portion 21b and the second displacement absorbing portion 22b) provided with the reinforcing member 40. I was able to. Furthermore, since the battery module 300 was able to sufficiently displace the pressing parts (the first pressing part 21a and the second pressing part 22a), the maximum value of the pressure measured in the chamber is suppressed to 28 kPa. I was able to. As a result, the differential value obtained by differentiating the maximum value of pressure was sufficiently suppressed to 80 kPa / sec. The reinforcing member 40 of the battery module 300 is broken.

  According to the battery module 300 which concerns on 3rd Embodiment mentioned above, there exists an effect by the following structures.

  The battery module 300 includes a reinforcing member 40 that reinforces the deformation absorbing portion (at least one of the first displacement absorbing portion 21b and the second displacement absorbing portion 22b). The reinforcing member 40 has lower strength or ductility than the exterior body (laminate sheet 14).

  According to such a configuration, when the laminate sheet 14 of the unit cell 10 is deformed to a certain level or more, the reinforcing member 40 is broken, and the deformation absorbing portion (at least the first displacement absorbing portion 21b and the second displacement absorbing portion 22b). The deformation of either one of the above can be promoted. That is, when the pressing portion is pressed outward by the expanded unit cell 10, the deformation absorbing portion can be reliably displaced so as to reduce the deformation amount of the pressing portion. Therefore, the battery module 300 can prevent the unit cell 10 that expands from being excessively pressed.

  In addition, the present invention can be variously modified based on the configurations described in the claims, and these are also within the scope of the present invention.

  For example, in the first to third embodiments, the unit cell 10 has been described with the configuration of a lithium ion secondary battery, but is not limited to such a configuration. The unit cell 10 can be configured as, for example, a polymer lithium battery, a nickel-hydrogen battery, or a nickel-cadmium battery.

  In the first to third embodiments, the unit cell 10 has been described as a configuration of a secondary battery that is repeatedly charged and discharged, but is not limited to such a configuration. The single battery 10 can be configured as a primary battery that is used only once.

10 cells,
11 positive electrode,
11a positive electrode current collector,
11b positive electrode active material,
11c positive electrode terminal,
12 negative electrode,
12a negative electrode current collector,
12b negative electrode active material,
12c negative electrode terminal,
13 separator,
14 Laminate sheet (exterior body),
20, 30 enclosure,
21, 31 containment case,
21a, 31a 1st press part (press part),
21b, 31b first displacement absorber (displacement absorber),
31b1 first notch (notch),
22, 32 lids,
22a, 32a second pressing part (pressing part),
22b, 32b second displacement absorber (displacement absorber),
32b1 second notch (notch),
40 reinforcement members,
100, 200, 300 battery module,
K area,
X longitudinal direction,
Y short direction,
Z Stacking direction.

Claims (7)

A unit cell formed by sealing a power generation element formed by laminating a positive electrode and a negative electrode with a separator interposed therebetween,
Housing the unit cell in a pressed state,
The housing is
A pressing portion that presses the unit cell inward from at least one side in the stacking direction of the electrodes; and
A battery module comprising: a deformation absorbing portion that absorbs deformation of the pressing portion when the pressing portion is pressed outward by the expanded unit cell that is integrally formed with the pressing portion.   The battery module according to claim 1, wherein the deformation absorbing portion is lower in rigidity than the pressing portion.   The battery module according to claim 1, wherein the deformation absorbing portion is formed on an outer peripheral edge of the pressing portion.   The battery module according to any one of claims 1 to 3, wherein the deformation absorbing portion includes a cutout portion that is partially formed with a small cross-sectional area. A reinforcing member for reinforcing the deformation absorbing portion;
The battery module according to claim 1, wherein the reinforcing member has a strength or ductility smaller than that of the exterior body.   The battery module according to any one of claims 1 to 5, wherein the pressing unit presses the unit cell from both sides in the stacking direction of the electrodes.   The battery module according to claim 1, wherein a plurality of the single cells are provided along a stacking direction.