Battery module

Abstract

To provide a battery module of which the deposition strength at an inner surface side of a battery case is high and which has high pressure resistance.SOLUTION: A battery module comprises a battery case, a cell and an intermediate connection member 50. The cell includes: an electrode group including a cathode plate, an anode plate, a separator, a cathode-side lead section and an anode-side lead section; and a collector plate 37 which is welded and bonded to the cathode-side lead section and the anode-side lead section. The collector plate 37 includes a plurality of weld groove sections 39 and 40 which extend in a width direction and to which the cathode-side lead section and the anode-side lead section are welded. In the plurality of weld groove sections 39 and 40, the weld groove section 39 formed in a portion corresponding to a connection location of the intermediate connection member 50 is a short weld groove section 39 of which the length in the width direction is shorter than the other weld groove section 40 and both the ends in the width direction are closed. The intermediate connection member 50 is welded to a side face 37b of the collector plate 37 at one side in the width direction of a portion corresponding to a location where the short weld groove section 39 is formed.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a battery module. [Background technology]

[0002] Secondary batteries used as power sources for electrically powered vehicles such as electric cars and hybrid cars are used in the form of a battery module in which a plurality of secondary batteries are electrically connected to increase charge / discharge capacity and output power. Generally, this type of secondary battery includes a battery case in which battery elements are housed. For example, Patent Document 1 discloses a battery module having single cells in which a resin battery case constitutes an integrated battery case, and the integrated battery case is divided by partitions into a plurality of battery cases in which battery elements (electrode groups, current collectors, electrolyte) are housed.

[0003] In the battery module described in Patent Document 1, an electrode group in which positive and negative plates are stacked with a separator interposed therebetween has lead portions of the positive and negative plates protruding from the sides opposite each other. The current collector plate is a long plate-like member whose width direction is parallel to the stacking direction of the electrode group, and a plurality of welding grooves extending across the entire width of the one side surface are formed at intervals in the longitudinal direction on one side of the current collector plate. In the battery module, the side edges of each lead are welded to the other side surface of the current collector plate across the entire width at the locations where the welding grooves are formed, and each lead portion and the current collector plate are electrically connected.

[0004] In this battery module, the current collector plates of the individual cells are electrically connected at their upper ends via through holes formed in the partitions. In order to increase the number of current paths between the current collector plates of the individual cells and reduce internal resistance, adjacent current collector plates are electrically connected to each other via conductive intermediate connection members (conductive connection members) near the centers in the up-down direction (longitudinal direction) of the current collector plates via through holes also formed in the partitions, and the intermediate connection members are welded to the side surfaces in the width direction of each current collector plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2022-025600 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in the battery module described in Patent Document 1, no welding grooves are formed in the portions of the current collector plates corresponding to the points (connection points) where the current collector plates are connected to adjacent current collector plates by intermediate connecting members, and in these portions, the lead portions and the current collector plates are not welded but are simply in contact with each other.

[0007] Here, by increasing the number of welds between the leads and the current collector plate, the battery resistance can be reduced. Therefore, it is preferable to form weld grooves in the areas corresponding to the above-mentioned connection locations and weld the leads and current collector plate to these areas as well. However, in this case, there is a risk of poor welding between the current collector plate and the intermediate connection member.

[0008] That is, if a welding groove is formed across the entire width of one surface of the current collector plate in a portion corresponding to the connection point, an opening of the welding groove is formed on the side surface of the current collector plate. Also, if the side edges of the leads are welded across the entire width of the other surface of the current collector plate along the welding groove, burrs are generated on the side surface of the current collector plate.

[0009] In other words, if a weld groove having the same shape as the weld groove formed in another part is formed in the part corresponding to the above-mentioned connection part, the side surface of the current collecting plate, which is the welded part between the current collecting plate and the intermediate connecting member, will have openings in the weld groove and burrs generated during welding between the current collecting plate and each lead part. Therefore, when the current collecting plate and the intermediate connecting member are welded, the openings in the weld groove and burrs may interfere with each other, causing welding defects such as reduced strength and holes in the welded parts, which may degrade the performance of the battery module.

[0010] The present invention has been made in consideration of the above-mentioned situation, and has an object to provide a battery module in which the lead portion of the electrode group and the current collector plate are welded to each other at the connection points between the current collector plate and the intermediate connecting member, thereby ensuring electrical continuity between the two, while suppressing the occurrence of poor welding at the welding points between the current collector plate and the intermediate connecting member. [Means for solving the problem]

[0011] The battery module according to the present invention, which achieves the above object, has the following characteristic configuration: a battery case having a plurality of battery containers each having a storage space separated by a partition wall; A single battery contained in the battery case; and an intermediate connecting member electrically connecting adjacent cells to each other, The single battery comprises: an electrode group including a positive electrode plate, a negative electrode plate, and a separator stacked together, the electrode group having a positive electrode lead portion at one end of the positive electrode plate in a specific direction perpendicular to the stacking direction, and a negative electrode lead portion at the other end of the negative electrode plate in the specific direction; a current collector plate welded to the positive electrode lead portion and the negative electrode lead portion, the width direction of the current collector plate being parallel to the lamination direction; the intermediate connection member electrically connects the current collector plates of the adjacent unit cells via through holes formed in the partition wall, The current collector plate is a plurality of welding grooves extending along the width direction and to which the positive electrode side lead portion and the negative electrode side lead portion are welded; Among the plurality of weld grooves, the weld groove formed in the portion corresponding to the connection location of the intermediate connection member is a short weld groove having a length in the width direction shorter than the other weld grooves and both ends in the width direction closed, The intermediate connection member is welded to one side surface in the width direction of a portion of the current collector plate corresponding to the location where the short weld groove portion is formed.

[0012] According to the above characteristic configuration, the positive electrode lead portion and the negative electrode lead portion are welded to a short weld groove formed in a portion corresponding to the connection portion of the intermediate connection member. Furthermore, no openings are present in the weld groove at the weld portion between the current collector plate and the intermediate connection member, and burrs are suppressed at the weld portion between the current collector plate and the intermediate connection member. Therefore, according to the battery module having the above characteristic configuration, the lead portion of the electrode group and the current collector plate are welded at the connection portion between the current collector plate and the intermediate connection member, ensuring electrical continuity between them, while suppressing the occurrence of welding defects at the weld portion between the current collector plate and the intermediate connection member.

[0013] Further characteristic configurations of the battery module according to the present invention are as follows: The portion of the current collector plate corresponding to the outside in the width direction of the area where the short welded groove portion is formed is a thick plate portion that protrudes toward the electrode group more than the portion corresponding to the area where the short welded groove portion is formed.

[0014] When the positive electrode lead portion and the negative electrode lead portion are welded to the short weld groove portion, the portions of the positive electrode lead portion and the negative electrode lead portion located on the outer side in the width direction from the portion where the short weld groove portion is formed are not welded to the current collector plate. Therefore, a part of the lead portion and the current collector plate may be out of contact due to an external disturbance or the like, reducing the number of conductive points and increasing the electrical resistance. However, according to the above characteristic configuration, the portions of the positive electrode lead portion and the negative electrode lead portion located on the outer side in the width direction from the portion where the short weld groove portion is formed are more likely to come into contact with the thick plate portion of the current collector plate, thereby suppressing the increase in electrical resistance. Effect of the Invention

[0015] As described above, according to the battery module of the present invention, the lead portion of the electrode group and the current collector plate are welded to each other at the connection points between the current collector plate and the intermediate connecting member, thereby ensuring electrical continuity between the two, while suppressing the occurrence of poor welding at the weld points between the current collector plate and the intermediate connecting member. [Brief description of the drawings]

[0016] [Figure 1]FIG. 2 is an exploded perspective view showing a battery module according to one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III of FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] 5 is a diagram showing a cross section of part VV in FIG. 4. FIG. [Figure 6] FIG. 5 is a cross-sectional view taken along line VI-VI of FIG. [Figure 7] FIG. 13 is a diagram showing the welding mode between a current collecting plate and an intermediate connecting member, where (a) shows a case where the weld groove formed in the portion corresponding to the connection point of the intermediate connecting member is a long weld groove, and (b) shows a case where the weld groove formed in the portion corresponding to the connection point of the intermediate connecting member is a short weld groove. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, a battery module according to the present embodiment and a manufacturing method for the battery module will be described with reference to the drawings. In the following, an example in which the battery module includes nickel-metal hydride secondary batteries as unit cells will be described. In addition, in the following, each description and each drawing will be appropriately simplified in order to clarify the description.

[0018] [Configuration of battery module 1] 1 is an exploded perspective view showing a battery module 1 according to the present embodiment. 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 up-down direction, and the X-axis and Y-axis directions are perpendicular to each other and parallel to the horizontal direction.

[0019] As shown in FIG. 1, the battery module 1 includes a resin battery case 10 having a storage space 11 in which a battery element 31 is housed, a single battery 30 formed of the battery element 31 housed in the storage space 11, and the like.

[0020] [Configuration of battery case 10] 1, the battery case 10 is composed of a rectangular solid-shaped integrated battery case 12 having an opening 18 at the top formed so as to connect the storage space 11 to the outside, and a lid 2 that closes the opening 18 of the integrated battery case 12. In this embodiment, the integrated battery case 12 and the lid 2 are made of a weldable thermoplastic resin such as polypropylene.

[0021] The integrated battery case 12 is configured with a pair of side walls 13 that are disposed opposite each other along the longitudinal direction (X-axis direction) and have the widest outer wall surface area, a pair of end walls 14 that connect the ends of the side walls 13 in the longitudinal direction (X-axis direction), and a bottom 15 that closes the bottom, and these are integrally molded with resin. In this embodiment, the storage space 11 is a space that is surrounded by the lid 2, the side walls 13, the end walls 14, and the bottom 15, and the storage space 11 is equally separated by five partition walls 16, and six battery cases 17, i.e., a plurality of battery cases 17, are formed along the X-axis direction.

[0022] The outer wall surface of each side wall 13 is provided with a plurality of position adjustment parts 19 used for aligning with the adjacent battery module 1, and passage forming protrusions 20 formed to protrude in the thickness direction (Y-axis direction) of the side wall 13 and form cooling passages between the adjacent battery modules 1. In this embodiment, three pairs of position adjustment parts 19 are provided.

[0023] An opening window 21 sealed by a side cover 22 is formed in each side wall 13 so as to straddle the partition wall 16. In this embodiment, three opening windows 21 are formed in one of the pair of side walls 13, and two opening windows 21 are formed in the other side wall 13. That is, in this embodiment, five opening windows 21 are formed in the battery case 10 as a whole.

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

[0025] The length of the lid 2 in the longitudinal direction (X-axis direction) is approximately the same as the long side of the side wall 13 of the integrated battery case 12, and the length of the lid 2 in the transverse direction (Y-axis direction) is approximately the same as the short side of the end side wall 14 of the integrated battery case 12. The lid 2 has a lower peripheral edge welded to the edge of the opening 18 of the integrated battery case 12, thereby air-tightly closing the opening 18 of the integrated battery case 12.

[0026] In addition, in this embodiment, the lid body 2 is formed as a hole penetrating in the thickness direction and is equipped with a measurement section 6 into which a temperature sensor such as a thermocouple is inserted, and a discharge valve 7 for opening to release the internal pressure when the internal pressure of the battery case 10 reaches or exceeds a threshold value.

[0027] [Configuration of the cell 30] Next, the configuration of the cell 30 will be described with reference to Figs. 2 to 6. Fig. 2 is a cross-sectional view showing part II-II in Fig. 1. Fig. 3 is a cross-sectional view showing part III-III in Fig. 1, but the detailed configuration of the battery element 31 is omitted. Fig. 4 is a cross-sectional view showing part IV-IV in Fig. 3. Fig. 5 is a cross-sectional view showing part VV in Fig. 4. Fig. 6 is a cross-sectional view showing part VI-VI in Fig. 4.

[0028] As shown in FIG. 2, in this embodiment, the single cell 30 is a nickel-hydrogen secondary battery composed of battery elements 31 housed in each battery case 17. The battery elements 31 include an electrode group 32, current collectors 37 and 45, a conductive plate 46, and an electrolyte (not shown). The electrode group 32 is configured by stacking a plurality of positive electrode plates 33, negative electrode plates 34, and separators 35. Specifically, as shown in FIG. 5 and FIG. 6, the electrode group 32 is configured by stacking the positive electrode plates 33 and the negative electrode plates 34 with the separators 35 interposed therebetween along the Y-axis direction. The plurality of positive electrode plates 33 have a positive electrode lead portion 33a at one end (one end) in the X-axis direction perpendicular to the stacking direction. The plurality of negative electrode plates 34 have a negative electrode lead portion 34a at the other end (other end) in the X-axis direction. The details will be described later, but the current collectors 37 and 45 are welded to the positive electrode lead portion 33a and the negative electrode lead portion 34a. In this embodiment, the X-axis direction corresponds to the "specific direction".

[0029] In this embodiment, two types of current collector plates (a first current collector plate 37 and a second current collector plate 45) having different shapes are used for the current collector plates 37, 45. The first current collector plate 37 is connected to the lead portions 33a, 34a between the single cells 30, and the second current collector plate 45 is connected to the lead portions 33a, 34a of the single cells 30 made up of the battery elements 31 housed in the battery cases 17 at both ends in the X-axis direction, and to a conductive plate 46 described below. In this embodiment, the first current collector plate 37 corresponds to the "current collector plate".

[0030] The first current collecting plate 37 is a long, belt-like folded plate. In this embodiment, the first current collecting plate 37 has an accommodating recess 38 formed by bending a widthwise end toward the side facing the lead portions 33a, 34a, and the side edges of the lead portions 33a, 34a are accommodated in the accommodating recess 38. The first current collecting plate 37 also has a plurality of weld grooves 39, 40 that open on a first surface 37a opposite to the side facing the lead portions 33a, 34a and extend along the width direction (Y-axis direction).

[0031] 4, in the first current collecting plate 37 of this embodiment, one short weld groove 39 and four long weld grooves 40 are formed at intervals in the longitudinal direction (Z-axis direction) of the first current collecting plate 37. The short weld groove 39 is formed in a portion (portion A in FIG. 4) corresponding to a location where an intermediate connecting member 50 described later is connected, and three long weld grooves 40 are formed above the short weld groove 39 and one is formed below the short weld groove 39.

[0032] The long weld groove portion 40 is a groove formed across the entire width of the first current collector plate 37, and openings of the long weld groove portion 40 are formed on the side surfaces 37b and 37c of the first current collector plate 37.

[0033] On the other hand, the short weld groove portion 39 is a groove that is shorter in the width direction than the long weld groove portion 40, and no opening of the short weld groove portion 39 is formed on the side surfaces 37b, 37c of the first current collecting plate 37. In other words, the short weld groove portion 39 is a groove whose both ends in the width direction are closed. Specifically, the length of the short weld groove portion 39 in this embodiment is shorter than the width of the accommodating recess 38 in the Y-axis direction.

[0034] The first current collecting plate 37 has a connection portion 42 on the upper end side that protrudes toward the opposite side to the lead portions 33a, 34a. An annular ring receiving portion 43 that protrudes toward the lead portions 33a, 34a is formed around the connection portion 42, and an annular space that receives an O-ring 44 is formed on the opposite side to the lead portions 33a, 34a in the ring receiving portion 43.

[0035] In this embodiment, an O-ring 44 accommodated in the annular space of each first current collector plate 37 is pressed against the periphery of the through hole 16a of the partition wall 16, and the pressing force causes each battery case 17 to be airtightly blocked from the through hole 16a. In this state, the first current collector plates 37 are joined to each other by spot welding through the through holes 16a provided in the partition wall 16. In addition, although details will be described later, in this embodiment, adjacent first current collector plates 37 are electrically connected to each other through intermediate connection members 50 arranged in the through holes 16b of the partition wall 16. Therefore, in this embodiment, adjacent single cells 30 are electrically connected in series.

[0036] The second current collector 45 is a long, belt-like folded plate. In this embodiment, the second current collector 45 has a recess (not shown) formed by bending the widthwise end toward the side facing the lead portions 33a, 34a, similar to the first current collector 37, and the side edges of the lead portions 33a, 34a are accommodated in the recess. Although detailed description is omitted, the second current collector 45 also has a plurality of open weld grooves formed on the surface opposite to the side facing the lead portions 33a, 34a.

[0037] The conductive plate 46 is disposed at a position facing the end sidewall 14 of the integrated battery case 12, and is electrically connected to the connection terminal 23. Although a detailed description will be omitted, the conductive plate 46 in this embodiment is disposed between each end sidewall 14 of the integrated battery case 12 and a second current collector plate 45 disposed at a position facing each end sidewall 14, and is electrically connected to the connection terminal 23 and the second current collector plate 45.

[0038] [Welding Mode Between First Current Collector Plate 37 and Lead Portions 33a, 34a] Next, the manner in which the first current collecting plate 37 is welded to each of the lead portions 33a, 34a will be described. The first current collecting plate 37 and each of the lead portions 33a, 34a are welded to the long weld groove portion 40 and the short weld groove portion 39 of the first current collecting plate 37. Note that, below, the manner in which the first current collecting plate 37 is welded to the positive electrode side lead portion 33a will be described with reference to Figs. 4 to 6, and the manner in which the first current collecting plate 37 is welded to the negative electrode side lead portion 34a will be similar except that the lead portion to be welded is the negative electrode side lead portion 34a, so a detailed description thereof will be omitted.

[0039] 4 and 5, in the long weld groove 40 of this embodiment, the bottom of the long weld groove 40 is melted and the positive electrode side lead 33a is welded over the entire width of the accommodating recess 38 while the side edge of the positive electrode side lead 33a accommodated in the accommodating recess 38 of the first current collector 37 is in contact with the bottom surface 38a of the accommodating recess 38 of the first current collector 37 (reference symbol M1 in FIG. 5 indicates a welded portion between the first current collector 37 and the positive electrode side lead 33a). Therefore, burrs due to welding are generated on both side surfaces 37b, 37c of the first current collector 37 corresponding to the location where the long weld groove 40 is formed.

[0040] On the other hand, in the short weld groove portion 39, as shown in Figures 4 and 6, with the side edge portion of the positive electrode side lead portion 33a accommodated in the accommodating recess 38 of the first current collecting plate 37 in contact with the bottom surface 38a of the accommodating recess 38 of the first current collecting plate 37, the bottom of the short weld groove portion 39 is melted and the positive electrode side lead portion 33a is welded to the accommodating recess 38 (symbol M2 in Figure 6 is the weld portion between the first current collecting plate 37 and the positive electrode side lead portion 33a).

[0041] Here, the length of the short weld groove portion 39 is shorter than the width in the Y-axis direction of the accommodating recess 38. Therefore, no burrs due to welding are generated on both side surfaces 37b, 37c of the first current collecting plate 37 corresponding to the locations where the short weld groove portion 39 is formed.

[0042] 6, the side edge of the positive electrode lead 33a is not welded to a surface of the bottom surface 38a of the accommodation recess 38 in the first current collector 37 that corresponds to a portion of the first surface 37a where the short weld groove 39 is not formed. Therefore, there are cases where a disturbance or the like causes a non-contact state between a part of the positive electrode lead 33a and the first current collector 37, reducing the number of conductive points and increasing the electrical resistance.

[0043] Therefore, in this embodiment, the portion of the first current collecting plate 37 corresponding to the portion where the short weld groove portion 39 is not formed is a thick plate portion 41 having a plate thickness greater than the other portions, and the portion of the bottom surface 38a of the accommodation recess 38 in the first current collecting plate 37 corresponding to the thick plate portion 41 is an inclined surface 41a inclined toward the center in the longitudinal direction (Y-axis direction) of the short weld groove portion 39. More specifically, in this embodiment, the inclined surface 41a is tapered such that the inter-face distance gradually decreases toward the center in the longitudinal direction (Y-axis direction) of the short weld groove portion 39. That is, in the battery module 1, the portion of the first current collecting plate 37 corresponding to the outer side in the width direction (Y-axis direction) of the portion where the short weld groove portion 39 is formed is a thick plate portion 41 that protrudes toward the electrode group 32 more than the portion corresponding to the portion where the short weld groove portion 39 is formed.

[0044] Therefore, in this embodiment, the side edge portion of the positive electrode side lead portion 33a that is not welded can easily come into contact with the inclined surface 41a of the accommodating recess 38, making it easier to ensure a conductive point between the positive electrode side lead portion 33a and the first current collecting plate 37, thereby suppressing an increase in electrical resistance.

[0045] [Connection between adjacent first current collecting plates 37 using intermediate connecting member 50] Next, a mode in which adjacent first current collector plates 37 are connected by an intermediate connection member 50 will be described.

[0046] 2 and 3, the intermediate connection member 50 is a conductive member electrically connected to each of the adjacent first current collecting plates 37 across the partition wall 16 of the battery case 10. That is, adjacent first current collecting plates 37 are electrically connected by two intermediate connection members 50. In this embodiment, the intermediate connection member 50 is a member that is generally L-shaped when viewed in the Z-axis direction, and has a base 51 having a connection portion 51a that is connected to an adjacent intermediate connection member 50 at a middle position in the Y-axis direction, and a flange portion 52 that extends in the X-axis direction from an end portion of the base 51 in the Y-axis direction.

[0047] In this embodiment, the intermediate connection member 50 is disposed such that the base 51 is located between the partition wall 16 and the first current collector plate 37, and the connection portion 51a is located in the through hole 16b of the partition wall 16. The connection portions 51a of the adjacent intermediate connection members 50 are electrically connected in the through hole 16b. In addition, the flange portion 52 of each intermediate connection member 50 is welded to the side surface 37b of the first current collector plate 37 facing the opening window 21 of the battery case 10. That is, the intermediate connection member 50 is welded to the side surface 37b on one side in the width direction (Y-axis direction) of the portion (A portion in FIG. 4) of the first current collector plate 37 corresponding to the portion where the short weld groove portion 39 is formed. In addition, the electrolyte in each battery case 17 is watertightly isolated by an O-ring 55 provided between the partition wall 16 and the intermediate connection member 50.

[0048] 7 is a diagram for explaining the welding mode between first current collecting plate 37 and intermediate connection member 50, and shows the connection point (part B in FIG. 2) between first current collecting plate 37 and intermediate connection member 50. Note that Fig. 7(a) shows a case where the weld groove formed in the portion corresponding to the connection point of intermediate connection member 50 is a long weld groove, and Fig. 7(b) shows a case where the weld groove formed in the portion corresponding to the connection point of intermediate connection member 50 is a short weld groove 39.

[0049] Here, if the long weld groove 40 is formed on the first surface 37a corresponding to the location of the first current collecting plate 37 where the intermediate connection member 50 is connected, as shown in Fig. 7(a), an opening of the long weld groove 40 will be present at the welded portion M3 between the flange portion 52 of the intermediate connection member 50 and the side surface 37b of the first current collecting plate 37, and as described above, burrs will be present on the side surface 37b during welding. In this case, the opening and burrs of the long weld groove 40 may interfere with each other, causing welding defects such as a decrease in strength or holes in the welded portion M3.

[0050] 7(b), in this embodiment, a short weld groove 39 is formed on the first surface 37a of the first current collecting plate 37 corresponding to the location where the intermediate connection member 50 is connected. Therefore, no openings for the short weld groove 39 are present on the flange portion 52 of the intermediate connection member 50 and the side surface 37b of the first current collecting plate 37, and no burrs are generated due to welding. This prevents welding defects from occurring at the welded portion M3.

[0051] As described above, in the battery module 1 of this embodiment, at the connection point between the first current collector 37 and the intermediate connecting member 50, the lead portions 33a, 34a of the electrode group 32 are welded to the first current collector 37, ensuring electrical continuity between the two while suppressing the occurrence of poor welding at the welding point between the first current collector 37 and the intermediate connecting member 50.

[0052] [Another embodiment] [1] In the above embodiment, one short weld groove 39 and four long weld grooves 40 are formed in the first current collecting plate 37, but the present invention is not limited to this. As long as the weld groove formed in the portion corresponding to the location where the intermediate connection member 50 is connected is a short weld groove, the number and details of the weld grooves are not particularly limited, and the present invention may be an embodiment in which a total of six or more short and long weld grooves are formed, or an embodiment in which all the weld grooves are short weld grooves.

[0053] [2] In the above embodiment, the thick plate portion 41 is formed on the first current collector 37, but the present invention is not limited to this. From the viewpoint of ensuring electrical connection between the lead portions 33a, 34a and the first current collector 37, it is preferable to form the thick plate portion 41, but the thick plate portion 41 may not be formed.

[0054] [3] In the above embodiment, the portion of the bottom surface 38a of the accommodating recess 38 in the first current collector 37 corresponding to the thick plate portion 41 is a tapered inclined surface 41a in which the inter-surface distance gradually decreases toward the center in the longitudinal direction (Y-axis direction) of the short welded groove portion 39, but the present invention is not limited to this. For example, the portion of the bottom surface 38a of the accommodating recess 38 in the first current collector 37 corresponding to the thick plate portion 41 may be a surface in which the amount of protrusion toward the electrode group 32 gradually decreases toward the center in the longitudinal direction (Y-axis direction) of the short welded groove portion 39, and may have any shape as long as it makes it easy for the positive electrode lead portion 33a to come into contact with the first current collector 37.

[0055] In addition, the configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided no contradiction arises. Furthermore, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope that does not deviate from the purpose of the present invention. [Explanation of symbols]

[0056] 1: Battery module 10: Battery case 11: Containment space 12: Integrated battery case (case body) 16: Bulkhead 16b: Through hole 17:Battery container 30: Single battery 32: Electrode group 33: Positive electrode plate 33a: Positive electrode lead part 34: Negative plate 34a: Negative electrode lead part 35: Separator 37: First current collector (current collector) 37b: Side 39: Short weld groove (weld groove) 40: Long weld groove section (weld groove section) 41: Thick plate section

Claims

1. a battery case having a plurality of battery containers each having a storage space separated by a partition wall; A single battery contained in the battery case; and an intermediate connecting member electrically connecting adjacent cells to each other, The single battery comprises: an electrode group including a positive electrode plate, a negative electrode plate, and a separator stacked together, the electrode group having a positive electrode lead portion at one end of the positive electrode plate in a specific direction perpendicular to the stacking direction, and a negative electrode lead portion at the other end of the negative electrode plate in the specific direction; a current collector plate welded to the positive electrode lead portion and the negative electrode lead portion, the width direction of the current collector plate being parallel to the lamination direction; the intermediate connection member electrically connects the current collector plates of the adjacent unit cells via through holes formed in the partition wall, The current collector plate is a plurality of welding grooves extending along the width direction and to which the positive electrode side lead portion and the negative electrode side lead portion are welded; Among the plurality of weld grooves, the weld groove formed in the portion corresponding to the connection location of the intermediate connection member is a short weld groove having a length in the width direction shorter than the other weld grooves and both ends in the width direction closed, The intermediate connection member is welded to a side surface on one side in the width direction of a portion of the current collector plate corresponding to a location where the short weld groove portion is formed.

2. 2. The battery module according to claim 1, wherein a portion of the current collector plate that corresponds to the outer side in the width direction of the portion where the short weld groove portion is formed is a thick plate portion that protrudes toward the electrode group more than a portion corresponding to the portion where the short weld groove portion is formed.

Images