Secondary battery

Abstract

To provide a secondary battery with which it is possible to suppress a decrease in battery life and realize an extended life.SOLUTION: The secondary battery comprises a battery case and a unit cell. The unit cell comprises: an electrode group 32 including a laminate part 32a formed by laminating a cathode plate 33, an anode plate 34, and a separator 35 and including a cathode-side lead part 33a consisting of one end of the cathode plate 33 and an anode-side lead part 34a consisting of the other end of the anode plate 34, with the electrode group 32 accommodated in each battery box in such a manner that a side wall 13 of the battery case and the laminate part 32a face each other; and a collector plate 37 disposed between the electrode group 32 and a bulkhead 16 of the battery case, with the cathode-side lead part 33a or the anode-side lead part 34a electrically connected. A heat exchange part 52 composed of tabular metal members is disposed between the laminate part 32a of the electrode group 32 and the side wall 13 of the battery case.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to secondary batteries.

Background Art

[0002] Conventionally, as a secondary battery used as a power source for electric vehicles and the like, a module-type battery in which a plurality of single cells are electrically connected to increase the charge / discharge amount and output power is known. As this type of secondary battery, for example, the battery described in Patent Document 1 has been proposed.

[0003] The battery described in Patent Document 1 includes a plurality of single cells in which power generation elements (electrode plate groups, current collector plates, electrolytic solution) are accommodated in a plurality of accommodation portions formed by partitioning the inside of a rectangular resin case with partition walls.

[0004] In this battery, the electrode plate group is formed by laminating a positive electrode plate and a negative electrode plate with a separator interposed therebetween, current collector plates are joined to both sides of the electrode plate group, and the current collector plates are electrically connected to each other, whereby a plurality of single cells are electrically connected in series.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in the battery described in Patent Document 1, during the use of the battery, the temperature of the single cell rises, and the increase in the temperature of the single cell may accelerate the deterioration of the electrode plate. Further, in the battery described in Patent Document 1, various factors such as the position of the joint between the electrode plate group and the current collector plate and the cooling mode of the battery cause a temperature difference between the electrode plate groups of each single cell and within the electrode plate group of the same single cell, and there is a possibility that a difference occurs in the deterioration rate of each electrode plate group and a variation occurs in the battery performance of each single cell. Such deterioration of the electrode plate and variation in battery performance between single cells lead to a decrease in battery life. That is, there is room for improvement in the battery described in Patent Document 1 in terms of suppressing the decrease in battery life.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a secondary battery capable of suppressing a decrease in battery life and achieving a long life.

Means for Solving the Problems

[0008] The characteristic configuration of the secondary battery according to the present invention for achieving the above object is a resin container having side walls, end side walls, and a bottom, and having a battery case having a plurality of battery cells formed by separating accommodation spaces by partition walls, a single cell housed in a plurality of the battery cells, and the single cell has a laminated portion formed by laminating a positive electrode plate, a negative electrode plate, and a separator, and has a positive electrode side lead portion formed from one end of the positive electrode plate and a negative electrode side lead portion formed from the other end of the negative electrode plate, and an electrode group housed in each battery cell so that the side wall of the battery case faces the laminated portion, a current collector plate disposed between the electrode group and the partition wall of the battery case, and having the positive electrode side lead portion or the negative electrode side lead portion electrically connected thereto, and a heat exchange portion made of a plate-shaped metal member is disposed between the laminated portion of the electrode group and the side wall of the battery case.

[0009] According to the above characteristic configuration, since the heat exchange part is disposed between the stacked part and the side wall, heat exchange between the electrode group and the heat exchange part proceeds, and the heat of the heat exchange part is released to the outside through the side wall. Therefore, the temperature of the electrode group is likely to decrease. Thus, according to the above characteristic configuration, it is easy to reduce the temperature difference between the electrode groups of each single battery and the temperature difference within the electrode group of the same single battery, and it is possible to suppress variations in battery performance due to differences in the deterioration rate of the electrode groups. Further, since the maximum temperature of the electrode group can be lowered by heat exchange with the heat exchange part, deterioration of the electrode plate can be suppressed. Therefore, according to the above characteristic configuration, it is possible to suppress a decrease in battery life due to deterioration of the electrode plate and variations in battery performance, and to achieve a longer battery life.

[0010] A further characteristic configuration of the secondary battery according to the present invention is provided with an intermediate connection member that electrically connects the current collector plates of adjacent single batteries through through-holes formed in the partition wall of the battery case. The heat exchange part is constituted by a part of either one of the two intermediate connection members that connect adjacent single batteries.

[0011] According to the above characteristic configuration, the joint part between the intermediate connection members that are likely to be heated by heat generated by electrical resistance during use of the secondary battery and the joint part between the intermediate connection member and the current collector plate are physically connected to the heat exchange part. Therefore, the heat generated at the welded part is transmitted to the heat exchange part and is released from the heat exchange part to the outside through the side wall. Thus, local overheating of the joint part and the part of the electrode group located near the joint part is suppressed. Therefore, according to the above characteristic configuration, local deterioration of the electrode plate can be suppressed, a decrease in battery life can be suppressed, and a longer battery life can be achieved.

[0012] A further characteristic configuration of the secondary battery according to the present invention is a window part that communicates the inside of the battery container with the outside is formed on the side wall of the battery case so as to straddle the partition wall. The intermediate connection member is disposed at a position overlapping the window part when viewed in a direction orthogonal to the side wall of the battery case. The window portion is welded to the battery case and is blocked by the side cover.

[0013] According to the above characteristic configuration, as described above, the temperature rise of the joint portions between the intermediate connection members and the joint portion between the intermediate connection member and the current collector plate is suppressed, and the temperature of the side cover disposed in the vicinity of the joint portion is not likely to rise. Therefore, the permeation of gas from inside the battery case through the side cover to the outside is suppressed, and the depletion of the electrolytic solution is suppressed. Accordingly, according to the above characteristic configuration, a decrease in battery life can be suppressed, and a longer life can be achieved.

Effects of the Invention

[0014] As described above, according to the secondary battery according to the present invention, a decrease in battery life can be suppressed, and a longer life can be achieved.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0016] Hereinafter, the secondary potential according to the present embodiment will be described with reference to the drawings. In the following, an aspect in which the secondary battery is in the form of a battery module including a plurality of nickel-metal hydride secondary batteries as single cells will be described as an example. Also, in the following, for the sake of clarity, each description and each drawing are appropriately simplified.

[0017] 〔Configuration of Battery Module 1〕 FIG. 1 is an exploded perspective view showing a battery module 1 according to the present embodiment. FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III. In the following description, the direction parallel to the height direction of the battery module 1 is defined as the Z-axis direction, the direction parallel to the longitudinal direction of the battery module 1 is defined as the X-axis direction, and the direction parallel to the thickness direction of the battery module 1 is defined as the Y-axis direction. The Z-axis direction is parallel to the vertical direction, the X-axis direction and the Y-axis direction are orthogonal to each other, and are parallel to the horizontal direction.

[0018] As shown in FIG. 1, the battery module 1 includes a battery case 10 which is a resin container having an accommodation space 11 for accommodating battery elements 31, and single cells 30 each including battery elements 31 accommodated in the accommodation space 11.

[0019] 〔Configuration of Battery Case 10〕 As shown in FIGS. 1 and 2, the battery case 10 includes a rectangular parallelepiped-shaped integral battery cell 12 having an opening 18 formed at the upper part for communicating the accommodation space 11 with the outside, and a lid body 2 for closing the opening 18 of the integral battery cell 12. In the present embodiment, the integral battery cell 12 and the lid body 2 are made of a weldable thermoplastic resin such as polypropylene.

[0020] The integral battery cell 12 is composed of a pair of side walls 13 provided opposite to each other along the longitudinal direction (X-axis direction) and having the outermost wall surface 13a with the largest area, a pair of end side walls 14 connecting the ends of the side walls 13 in the longitudinal direction (X-axis direction), and a bottom portion 15 for closing the bottom, and these are integrally formed by resin molding. In the present embodiment, the accommodation space 11 is a space surrounded by the lid body 2, the side walls 13, the end side walls 14, and the bottom portion 15, and the accommodation space 11 is equally divided by five partition walls 16, and six battery cells 17 are formed along the X-axis direction.

[0021] On the outer wall surface 13a of each side wall 13, there are provided a plurality of position adjusting parts 19 used for alignment with the adjacent battery module 1, and passage forming protrusions 20 formed so as to protrude in the thickness direction (Y-axis direction) of the side wall 13 and forming a cooling flow path between the adjacent battery modules 1. For example, by flowing cooling air from the lower side to the upper side between the outer wall surfaces 13a of the adjacent battery modules 1, the battery module 1 can be cooled and the temperature rise of the single battery 30 can be suppressed.

[0022] On each side wall 13, an opening window 21 sealed by a side lid 22 is formed so as to straddle the partition wall 16. In the present embodiment, three opening windows 21 are formed on one of the pair of side walls 13 and two on the other. That is, in the present embodiment, a total of five opening windows 21 are formed in the entire battery case 10. In FIG. 1, one of the opening windows 21 is shown in a state of not being blocked by the side lid 22, but in the completed battery module 1, all the opening windows 21 are blocked by the side lid 22. In the present embodiment, the opening window 21 corresponds to the "window part".

[0023] At a location corresponding to the opening window 21 on the outer wall surface 13a of each side wall 13, an opening is formed, and a sheet having an outer shape smaller than that of the outer wall surface 13a is adhered. The sheet is adhered to suppress the permeation of gases such as hydrogen generated inside each single battery 30 from the resin battery case 10. Therefore, the material of the sheet is not particularly limited as long as it has a low desired gas permeability. In this example, a sheet having extremely low hydrogen permeability, which is composed of a laminated sheet in which aluminum, resin, etc. are laminated, is adhered to the outer wall surface 13a of the side wall 13.

[0024] At the upper end side of each end side wall 14, a terminal mounting part (not shown) penetrating in the thickness direction (X-axis direction) is formed, and a connection terminal 23 for taking out the output of the single battery 30 to the outside is mounted on the terminal mounting part.

[0025] On each partition wall 16, a first through hole 16a is formed at the upper end side, and a second through hole 16b is formed at a position corresponding to the opening window 21 in a front view (see FIG. 3).

[0026] The lid body 2 is formed such that the length in the longitudinal direction (X-axis direction) is substantially the same as the long side of the side wall 13 of the integral battery case 12, and the length in the short side direction (Y-axis direction) is substantially the same as the short side of the end side wall 14 of the integral battery case 12. The lid body 2 airtightly closes the opening 18 of the integral battery case 12 by welding the peripheral portion of the lower surface to the edge of the opening 18 of the integral battery case 12.

[0027] Also, in the present embodiment, the lid body 2 is formed as a hole penetrating in the thickness direction (Z-axis direction), and includes a measurement portion 6 into which a temperature sensor such as a thermocouple is inserted, and a discharge valve 7 that opens to release the internal pressure when the internal pressure of the battery case 10 becomes equal to or higher than a threshold value.

[0028] 〔Configuration of single battery 30〕 Next, the configuration of the single battery 30 will be described. As shown in FIGS. 1 to 3, in the present embodiment, the single battery 30 is a nickel-metal hydride secondary battery composed of battery elements housed in each battery cell 17. That is, in the present embodiment, six single batteries 30 arranged with the partition wall 16 interposed therebetween along the X-axis direction are provided. The battery element 31 includes an electrode group 32, a current collector plate 37, a conductive plate 38, an electrolytic solution (not shown), and the like.

[0029] The electrode group 32 has a stacked portion 32a in which a plurality of positive electrode plates 33 and negative electrode plates 34 are stacked in the Y-axis direction with a separator 35 interposed therebetween. Also, the plurality of positive electrode plates 33 have positive electrode side lead portions 33a at one end in the direction orthogonal to the stacking direction (X-axis direction). Also, the plurality of negative electrode plates 34 have negative electrode side lead portions 34a at the other end in the X-axis direction. A current collector plate 37 is welded to the tip of each of the positive electrode side lead portion 33a and the negative electrode side lead portion 34a.

[0030] In this embodiment, the current collector plate 37 is a long corrugated plate. Specifically, the current collector plate 37 has a base portion 37a facing the lead portions 33a and 34a, and bent portions 37b formed by bending the end portions in the width direction (Y-axis direction) of the base portion 37a toward the sides of the lead portions 33a and 34a, and each of the lead portions 33a and 34a is welded to the base portion 37a. Further, the current collector plate 37 has a connection portion 37c at the upper end of the base portion 37a, and is electrically connected to the current collector plate 37 connected to the adjacent single battery 30.

[0031] The conductive plate 38 is disposed at a position facing the end side wall 14 of the integral battery case 12 and is electrically connected to the connection terminal 23. Although detailed description is omitted, the conductive plate 38 of this embodiment is disposed between each end side wall 14 of the integral battery case 12 and the current collector plate 37 disposed at a position facing each end side wall 14, and is electrically connected to the connection terminal 23 and the current collector plate 37.

[0032] Further, in this embodiment, the current collector plates 37 of the adjacent single batteries 30 sandwiching the partition wall 16 of the battery case 10 are electrically connected by two conductive intermediate connection members 40 and 50 (a first intermediate connection member 40 and a second intermediate connection member 50). In this embodiment, the current collector plates 37 of a total of five single batteries 30 from the second one from the right to the left end toward the paper surface of FIG. 2 are connected by the first intermediate connection member 40 and the second intermediate connection member 50, and the current collector plates 37 of the two single batteries 30 on the right side are electrically connected by two first intermediate connection members 40. Therefore, in this embodiment, the heat exchange portion 52 described later is disposed between the four single batteries 30 excluding the two single batteries 30 located on both sides in the X-axis direction among the six single batteries 30 and the side wall 13 of the battery case 10 (see FIG. 2). Also, in this embodiment, each of the intermediate connection members 40 and 50 is made of a Ni-plated steel plate, but any material may be used as long as each of the intermediate connection members 40 and 50 has conductivity.

[0033] The first intermediate connection member 40 is a member that is substantially L-shaped when viewed in the Z-axis direction, and has a base portion 41 having a connection portion 41a connected to an adjacent second intermediate connection member 50 at an intermediate position in the Y-axis direction, and a flange portion 42 extending in the X-axis direction from an end portion of the base portion 41 in the Y-axis direction.

[0034] The first intermediate connection member 40 is arranged such that the base portion 41 is located between the partition wall 16 and the current collector plate 37, and the connection portion 41a is located in the second through hole 16b of the partition wall 16. Further, the first intermediate connection member 40 is welded to the surface of the bent portion 37b on the side where the flange portion 42 faces the opening window 21 of the battery case 10 in the current collector plate 37, and is electrically connected to the current collector plate 37.

[0035] The second intermediate connection member 50 is a member that is substantially U-shaped when viewed in the Z-axis direction, and has a base portion 51 and a heat exchange portion 52 extending in the X-axis direction from an end portion of the base portion 51 in the Y-axis direction. That is, the heat exchange portion 52 is made of a plate-shaped metal member and is constituted by a part of the intermediate connection member.

[0036] The second intermediate connection member 50 is arranged such that the base portion 51 is located between the partition wall 16 and the current collector plate 37, and the heat exchange portion 52 is located between the electrode group 32 and each side wall 13 of the battery case 10. More specifically, the second intermediate connection member 50 is arranged such that the heat exchange portion 52 is located between the surfaces on both sides in the stacking direction (Y-axis direction) of the positive electrode side lead portion 33a and the stacked portion 32a of the electrode group 32 and the side wall 13 of the battery case 10. Further, the second intermediate connection member 50 is welded to the surface of each bent portion 37b in the current collector plate 37 by the heat exchange portion 52, and is electrically connected to the current collector plate 37.

[0037] In this embodiment, the heat exchange portion 52 of the second intermediate connection member 50 is substantially rectangular when viewed in the Y-axis direction, the length in the longitudinal direction (Z-axis direction) is substantially the same as the length in the Z-axis direction of the stacked portion 32a of the electrode group 32, and the length in the short-side direction (X-axis direction) is substantially the same as the length in the X-axis direction obtained by combining the stacked portion 32a of the electrode group 32 and the positive electrode side lead portion 33a. That is, in this embodiment, the heat exchange portion 52 covers substantially the entire positive electrode side lead portion 33a and the stacked portion 32a when viewed in the direction orthogonal to the outer wall surface 13a of the side wall 13 in the battery case 10 (viewed in the Y-axis direction).

[0038] In this embodiment, the current collecting plates 37 of adjacent single cells 30 are joined by spot welding of the connection portions 37c in contact with each other through the first through hole 16a. Further, the intermediate connection members 40 and 50 laser-welded to each current collecting plate 37 are joined by resistance welding and electrically connected. Specifically, the first intermediate connection member 40 and the second intermediate connection member 50 are joined by resistance welding in a state where the connection portion 41a of the first intermediate connection member 40 is in contact with the base portion 51 of the second intermediate connection member 50 through the second through hole 16b. Further, the first intermediate connection members 40 are joined by resistance welding in a state where the connection portions 41a are in contact with each other through the second through hole 16b. Further, the electrode groups 32 arranged on both end sides in the X-axis direction are electrically connected to the connection terminal 23 by the current collecting plates 37 and the conductive plates 38. Therefore, the battery module 1 of this embodiment has a configuration in which each single cell 30 is connected in series. Note that the symbol L in FIG. 3 is a joining portion where the current collecting plate 37 and the intermediate connection members 40 and 50 are joined by laser welding, and the symbol M is a joining portion where the first intermediate connection member 40 and the second intermediate connection member 50 are joined by resistance welding.

[0039] In the battery module 1 having the above configuration, when the battery module 1 is in use, the generation of a temperature difference between the electrode groups 32 of each single cell 30 or within the electrode group 32 of the same single cell 30, and the local temperature rise in the electrode group 32 are suppressed. Hereinafter, this will be described with reference to FIG. 4. Note that FIG. 4 is a diagram for explaining the effect of the battery module 1, and the thick arrows in the figure schematically show the movement of heat during use.

[0040] When having joints L between the current collector plate 37 and each of the intermediate connection members 40 and 50 and joint M between the intermediate connection members 40 and 50 as in the battery module 1 of the present embodiment, since the electrical resistance of these joints L and M is high, heat is likely to be generated at the joints L and M during energization. Then, the heat generated at the joints L and M is likely to be transmitted to portions located near these joints L and M, that is, portions of the electrode group 32 located near the joints L and M, the side wall 13 of the battery case 10, and the side lid 22 welded to the battery case 10. Therefore, if no measures are taken for these parts, the temperature can become higher compared to other parts.

[0041] Also, when flowing cooling air between the outer wall surfaces 13a of adjacent battery modules 1 and using the battery modules 1 while cooling them, a temperature difference occurs between the easily cooled portion and the difficult-to-cool portion. For example, when adopting the upflow method and flowing the cooling air from the lower side to the upper side, the lower side inside the battery module 1 is more easily cooled than the upper side. Therefore, the electrode group 32 housed in the battery module is less likely to have its temperature decreased towards the upper side, in other words, is likely to have its temperature increased.

[0042] Therefore, in the battery module 1, if no measures are taken, problems such as a temperature difference occurring between the electrode groups 32 of each single battery 30, a temperature difference occurring within the electrode group 32 of the same single battery 30, a part of the electrode group 32 becoming high-temperature, the side wall 13 and the side lid 22 becoming high-temperature, and the gas permeability of the resin constituting these increasing can occur.

[0043] However, in the battery module 1 according to the present embodiment, a heat exchange part 52 is arranged between the electrode group 32 (specifically, the laminated part 32a and the positive electrode side lead part 33a) and the side wall 13 of the battery case 10, and the heat exchange part 52 and the joints L and M are physically connected. Therefore, as shown in FIG. 4, heat exchange is possible between the electrode group 32 and the heat exchange part 52, and the heat generated at the joints L and M is efficiently transmitted to the heat exchange part 52.

[0044] Therefore, in the battery module 1 of the present embodiment, heat exchange progresses between the electrode group 32 and the heat exchange portion 52, and the heat of the heat exchange portion 52 is released to the outside through the side wall 13. Therefore, the temperature of the electrode group 32 is likely to decrease. As a result, the temperature difference between the electrode groups 32 of each single battery 30 and the temperature difference within the electrode group 32 of the same single battery 30 are reduced, and the variation in battery performance due to the difference in the deterioration rate of the electrode group 32 is also reduced. Furthermore, since the maximum temperature of the electrode group 32 is also lowered, the deterioration of the electrode plate is also suppressed.

[0045] In addition, since the heat generated at the joints L and M is efficiently transmitted to the heat exchange portion 52, the heat generated at the joints L and M is less likely to be transmitted to the electrode group 32, and local high-temperature rise in the electrode group 32 is suppressed. Therefore, local deterioration of the electrode group 32 is also suppressed.

[0046] In the battery module 1 of the present embodiment, in the gap spaces where the lead portions 33a and 34a and the current collector plate 37 are arranged in each battery case 17, since the gas generated between the electrode plates flows in, the gas is likely to fill. The side lid 22 closes the opening window 21 that communicates the gap space with the outside. Therefore, when the heat from the joints L and M causes the side lid 22 and the surrounding side wall 13 to become high in temperature and the gas permeability of the resin constituting the side lid 22 and the side wall 13 increases, there is a risk that the gas filling the gap space will leak to the outside through the side lid 22 and the surrounding side wall 13.

[0047] However, in the battery module 1 of the present embodiment, as described above, the joints L and M are physically connected to the heat exchange portion 52, and the heat generated at the joints L and M is transmitted to the heat exchange portion 52 and released to the outside through the side wall 13 from the heat exchange portion 52. That is, the heat generated at the joints L and M is less likely to be transmitted to the side wall 13 and the side lid 22 of the battery case 10 located near the joints L and M, and the temperature rise of the side wall 13 and the side lid 22 is suppressed. Therefore, the permeation of gas from the side wall 13 and the side lid 22 is suppressed, and the depletion of the electrolytic solution is suppressed.

[0048] Thus, according to the battery module 1 according to this embodiment, deterioration of the electrode plate, variation in battery performance, and exhaustion of the electrolytic solution can be suppressed, so that a decrease in battery life caused by these can be suppressed and a long life can be achieved.

[0049] 〔Alternative Embodiment〕 〔1〕In the above embodiment, the aspect in which the heat exchange portion 52 covers substantially the entire laminated portion 32a of the electrode group 32 and the positive electrode side lead portion 33a in a direction perpendicular to the outer wall surface 13a of the side wall 13 in the integrated battery case 12 (viewed in the Y-axis direction) has been described. However, the present invention is not limited to such an aspect. When adopting a cooling method in which cooling air flows between battery modules, depending on the way the cooling air flows, the locations where the temperature is difficult to decrease within the battery module change. Also, depending on the position of the joint portion between members, the locations where the temperature easily becomes high within the battery module also change. Therefore, in consideration of the way the cooling air flows and the position of the joint portion, it is preferable to arrange the heat exchange portion so that the temperature of locations where the temperature is difficult to decrease and locations where the temperature easily becomes high can be efficiently decreased. FIG. 5 is a cross-sectional view showing a part of a battery module according to an alternative embodiment. For example, as shown in FIG. 5, in a view in the Y-axis direction, an aspect in which the heat exchange portion 52 covers only the upper side of the electrode group 32 may be adopted. Even in such an aspect, when cooling the battery module in an upflow method, heat exchange between the heat exchange portion 52 and the electrode group 32 proceeds on the upper side of the electrode group 32 where the temperature is difficult to decrease, so that the temperature on the upper side of the electrode group 32 can also be efficiently decreased. Therefore, generation of a temperature difference between the electrode groups of each single battery, generation of a temperature difference within the electrode group of the same single battery, and local high temperature in the electrode group can be suppressed, so that a decrease in battery life can be suppressed and a long life can be achieved. From the viewpoint of suppressing the generation of the above temperature difference and local high temperature regardless of the way the cooling air flows and the position of the joint portion, it is preferable that the heat exchange portion covers 80% or more of the surface of the electrode group (laminated portion and lead portion) in a view in a direction perpendicular to the outer wall surface of the side wall in the battery case.

[0050] 〔2〕In the above embodiment, the mode in which the single cells 30 are electrically connected by the first intermediate connection member 40 and the second intermediate connection member 50 has been described, but the present invention is not limited to such a mode. An adjacent single cell 30 may be electrically connected only on the upper side of the current collector plate.

[0051] 〔3〕In the above embodiment, among the first intermediate connection member 40 and the second intermediate connection member 50 for electrically connecting two adjacent single cells 30, the mode in which the second intermediate connection member 50 has the heat exchange part 52 has been described, but the present invention is not limited to such a mode. For example, as described above, when adjacent single cells are electrically connected only on the upper side of the current collector plate without using an intermediate connection member, the current collector plate may have a heat exchange part. FIG. 6 is a cross-sectional view showing a part of a battery module according to another embodiment. In FIG. 6, the same components as those of the battery module 1 are denoted by the same reference numerals. In this case, as shown in FIG. 6, the current collector plate 60 has a base part 61 and a heat exchange part 62 extending in the X-axis direction from an end part of the base part 61 in the Y-axis direction, and is a member having a substantially U-shaped cross section when viewed in the Z-axis direction. In this case, the heat exchange part 62 of the current collector plate 60 may cover a part or all of the lead parts 33a and 34a and a part of the laminated part 32a when viewed in a direction orthogonal to the outer wall surface 13a of the side wall 13 in the battery case 10. Even in such a mode, heat exchange proceeds between the heat exchange part 62 and the electrode group 32, the heat of the heat exchange part 62 is released to the outside through the side wall 13, and the temperature of the electrode group 32 decreases. Therefore, the temperature difference between the electrode groups 32 of each single cell 30 and the temperature difference within the electrode group 32 of the same single cell 30 are reduced, the variation in battery performance is reduced, and the maximum temperature of the electrode group 32 also decreases. Therefore, even when the heat exchange part is constituted by a part of the current collector plate, variations in battery performance and a decrease in battery life due to deterioration of the electrode plate can be suppressed, and a longer life can be achieved.

[0052] 〔4〕In the above-described embodiment, the aspect in which the heat exchange portion 52 is disposed between the four single cells 30 excluding the two single cells 30 located on both sides in the X-axis direction among the six single cells 30 and the side wall 13 of the battery case 10 has been described. However, the present invention is not limited to such an aspect, and an aspect in which the heat exchange portion is disposed between all six single cells 30 and the side wall 13 of the battery case 10 may be employed. As described above, depending on the flow direction of the cooling air and the position of the welded portion, the locations where the temperature is difficult to decrease and the locations where the temperature tends to rise are different. Therefore, in consideration of the flow direction of the cooling air, the position of the welded portion, etc., it is preferable to dispose the heat exchange portion in the vicinity of the single cell where the temperature of the electrode group is difficult to decrease during use and the single cell where the electrode group tends to become high temperature.

[0053] 〔5〕In the above-described embodiment, the aspect in which the opening window 21 is formed in the side wall 13 of the integral battery tank 12 and the opening window 21 is closed by the side lid 22 has been described. However, the present invention is not limited to such an aspect, and an aspect in which the opening window 21 is not formed in the side wall 13 may be employed.

[0054] In addition, the configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction occurs. Also, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

Explanation of Reference Numerals

[0055] 1: Battery module (secondary battery) 10: Battery case 11: Accommodation space 13: Side wall 14: End side wall 15: Bottom 16: Partition wall 16b: Second through hole (through hole) 17: Battery tank 21: Opening window (window portion) 22: Side lid 30: Single cell 32: Electrode group 32a: Laminated part 33: Positive electrode plate 33a: Positive electrode side lead part 34: Negative electrode plate 34a: Negative electrode side lead part 35: Separator 37: Current collector plate 40: First intermediate connection member 50: Second intermediate connection member (one of the intermediate connection members) 52: Heat exchange part

Claims

1. A resin container having side walls, end side walls, and a bottom, comprising: a battery case having a plurality of battery cells formed by partitioning an accommodation space by partition walls; and a plurality of single cells accommodated in the plurality of battery cells, wherein the single cell has a laminated portion formed by laminating a positive electrode plate, a negative electrode plate, and a separator, and has a positive electrode side lead portion formed from one end of the positive electrode plate and a negative electrode side lead portion formed from the other end of the negative electrode plate, and an electrode group accommodated in each battery cell such that the side wall of the battery case faces the laminated portion; and a current collector plate disposed between the electrode group and the partition wall of the battery case, with the positive electrode side lead portion or the negative electrode side lead portion electrically connected thereto, a secondary battery in which a heat exchange portion made of a plate-like metal member is disposed between the laminated portion of the electrode group and the side wall of the battery case.

2. The secondary battery according to claim 1, further comprising an intermediate connection member that electrically connects the current collector plates of adjacent single cells through a through hole formed in the partition wall of the battery case, wherein the heat exchange portion is constituted by a part of either one of the two intermediate connection members that connect adjacent single cells.

3. A window portion that communicates the inside of the battery cell with the outside is formed on the side wall of the battery case so as to straddle the partition wall, the intermediate connection member is disposed at a position overlapping the window portion when viewed in a direction orthogonal to the side wall of the battery case, and the window portion is welded to the battery case and closed by a side lid.

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