Battery Module

Abstract

To provide a battery module that can maintain its strength and reduce its size.SOLUTION: A battery module comprises: a plurality of battery cells arranged side by side in a first direction and each having a rectangular shape; an end plate provided to be arranged side by side with the plurality of battery cells in the first direction; a restraint member that is provided to be arranged side by side with the plurality of battery cells and the end plate in a second direction orthogonal to the first direction and restrains the plurality of battery cells and the end plate along the first direction. The end plate includes a plate-shaped member. The plate-shaped member includes a plane portion, a flange portion that is provided at an end of the plate-shaped member in a third direction orthogonal to the first direction and the second direction and projects in the first direction from the plane portion, and a transition portion that makes a continuous transition from the plane portion to the flange portion. The plane portion, the transition portion, and the flange portion are provided side by side in the second direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] Conventionally, end plates are made of plate-like members, and flange portions are provided at the ends of the plate-like members. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-099648 A [Patent Document 2] JP 2015-069811 A Summary of the Invention [Problem to be solved by the invention]

[0004] Even when the plate-like members are deformed, it is necessary to avoid a decrease in the strength of the end plates due to stress concentration. From another perspective, it is necessary to secure the area of ​​the flat parts of the plate-like members to facilitate fastening to the binding members (bind bars) while satisfying the demand for compact battery modules.

[0005] An object of the present technology is to provide a battery module that can maintain strength while being compact. [Means for solving the problem]

[0006] The present technology provides the following battery module.

[0007] [1] A battery module comprising: a plurality of battery cells arranged side by side in a first direction, each having a rectangular shape; an end plate arranged to be side by side with the plurality of battery cells in the first direction; and a restraining member arranged to be side by side with the plurality of battery cells and the end plate in a second direction perpendicular to the first direction, the restraining member restraining the plurality of battery cells and the end plate along the first direction, wherein the end plate includes a plate-shaped member, the plate-shaped member including a planar portion and a flange portion provided at an end of the plate-shaped member in a third direction perpendicular to the first direction and the second direction, the flange portion protruding from the planar portion in the first direction, and a transition portion that continuously transitions from the planar portion to the flange portion, the planar portion, the transition portion, and the flange portion being arranged to be side by side in the second direction.

[0008] [2] The battery module described in [1], wherein the end plate is provided on a planar portion adjacent to the transition portion and includes a fastening portion that is fastened to the restraining member.

[0009] [3] The battery module described in [2], wherein the fastening portions are provided so as to be positioned at both ends of the end plate in the second direction.

[0010] [4] The battery module described in any one of [1] to [3], further comprising a case that houses and supports a plurality of battery cells in at least a first direction to form a unit including the plurality of battery cells.

[0011] [5] The battery module described in [4], wherein the plate-shaped members each have a protrusion and a recess that extend in the second direction and are aligned in the third direction, and the protrusion abuts against the case from the first direction.

[0012] [6] The battery module according to [4] or [5], wherein the units each include two or more battery cells, and the power density of each of the two or more battery cells is 8000 W / L or more. Effect of the Invention

[0013] According to the present technology, by providing a transition portion at the end of the plate-like member where the flat portion transitions continuously to the flange portion, it is possible to ensure the area of ​​the flat portion without hindering the miniaturization of the end plate while maintaining the strength of the end plate by the flange portion. As a result, it is possible to provide a battery module that can maintain strength while being miniaturized. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view showing a battery module. [Diagram 2] FIG. 2 is an exploded view showing the battery module. [Diagram 3] FIG. 2 is a perspective view showing a battery cell unit that constitutes a battery module. [Figure 4] FIG. 2 is a perspective view showing a battery cell that constitutes a battery cell unit. [Diagram 5] 13 is a side view showing the periphery of a contact portion between an end plate and a battery cell unit. FIG. [Figure 6] FIG. 1 is a perspective view (part 1) showing an end plate. [Figure 7] FIG. 2 is a second perspective view showing the end plate. [Figure 8] FIG. 4 is a perspective view showing a plate-like member constituting an end plate. [Figure 9] FIG. [Figure 10] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, embodiments of the present technology will be described. Note that the same or corresponding parts are denoted by the same reference characters, and description thereof will not be repeated.

[0016] In the embodiments described below, when referring to the number, amount, etc., the scope of the present technology is not necessarily limited to the number, amount, etc., unless otherwise specified. In addition, in the following embodiments, each component is not necessarily essential to the present technology, unless otherwise specified. In addition, the present technology is not necessarily limited to those that achieve all of the effects and advantages mentioned in the present embodiment.

[0017] In this specification, the words "comprise", "include" and "have" are open-ended, i.e., when a certain configuration is included, other configurations may or may not be included.

[0018] Furthermore, when geometric terms and terms expressing positional and directional relationships, such as "parallel," "orthogonal," "45° diagonal," "coaxial," and "along" are used in this specification, these terms allow for manufacturing errors and slight variations. When terms expressing relative positional relationships, such as "upper side" and "lower side," are used in this specification, these terms are used to indicate relative positional relationships in one state, and the relative positional relationships can be inverted or rotated to any angle depending on the installation direction of each mechanism (for example, by turning the entire mechanism upside down).

[0019] In this specification, the term "battery" is not limited to lithium ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium ion batteries. In this specification, the term "electrode" may collectively refer to a positive electrode and a negative electrode.

[0020] Fig. 1 is a perspective view showing a battery module in an embodiment of the present invention. Fig. 2 is an exploded view showing the battery module in Fig. 1. Fig. 3 is a perspective view showing a battery cell unit constituting the battery module in Fig. 1. Fig. 4 is a perspective view showing a battery cell constituting the battery cell unit in Fig. 1.

[0021] 1 to 4, a battery module 1 is used as a power source for driving a vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0022] In this specification, for convenience of explaining the structure of the battery module 1, an axis extending parallel to the stacking direction of the multiple battery cells 11 described later is referred to as the "Y axis", an axis extending in a direction perpendicular to the Y axis based on the "Y axis" is referred to as the "X axis", and an axis extending in a direction perpendicular to the Y axis and the X axis is referred to as the "Z axis". The diagonally upper right direction on the paper surface of FIG. 1 is the "+Y axis direction", and the diagonally lower left direction is the "-Y axis direction". The diagonally lower right direction on the paper surface of FIG. 1 is the "+X axis direction", and the diagonally upper left direction is the "-X axis direction". The upward direction on the paper surface of FIG. 1 is the "+Z axis direction", and the downward direction is the "-Z axis direction". Typically, the battery module 1 is mounted on a vehicle in a position in which the +Z axis direction corresponds to the upward direction, and the -Z axis direction corresponds to the downward direction.

[0023] First, there will be described the overall structure of the battery module 1. As shown in Fig. 2, the battery module 1 has a plurality of battery cell units 21 (21A, 21B, 21C, 21D, 21E, 21F).

[0024] The multiple battery cell units 21 are aligned in the Y-axis direction. Battery cell unit 21A, battery cell unit 21B, battery cell unit 21C, battery cell unit 21D, battery cell unit 21E, and battery cell unit 21F are aligned in the listed order from the negative side to the positive side in the Y-axis direction. Note that the number of battery cell units 21 provided in the battery module 1 is not particularly limited as long as it is two or more.

[0025] As shown in FIGS. 3 and 4, each of the battery cell units 21A to 21F has a plurality of battery cells 11 and a case body 31.

[0026] In each battery cell unit 21, two battery cells 11 are arranged consecutively in the Y-axis direction. The number of battery cells 11 provided in each battery cell unit 21 is not particularly limited as long as it is a plurality of battery cells.

[0027] The battery cells 11 are lithium ion batteries. As an example, the battery cells 11 may have a power density of 8000 W / L or more. The battery cells 11 have a rectangular shape. More specifically, the battery cells 11 have a rectangular parallelepiped thin plate shape. The multiple battery cells 11 are stacked such that the Y-axis direction is the thickness direction of the battery cells 11.

[0028] The battery cell 11 has an exterior body 12. The exterior body 12 is made of a rectangular parallelepiped housing, and forms the external appearance of the battery cell 11. The exterior body 12 contains an electrode assembly and an electrolyte.

[0029] Exterior body 12 has cell side surface 13, cell side surface 14, and cell top surface 15. Each of cell side surface 13 and cell side surface 14 consists of a plane perpendicular to the Y-axis direction. Cell side surface 13 and cell side surface 14 face opposite each other in the Y-axis direction. Each of cell side surface 13 and cell side surface 14 has the largest area among the multiple side surfaces that exterior body 12 has. Cell top surface 15 consists of a plane perpendicular to the Z-axis direction. Cell top surface 15 faces the +Z-axis direction.

[0030] Battery cell 11 further has a gas exhaust valve 17. Gas exhaust valve 17 is provided on cell top surface 15. Gas exhaust valve 17 is provided in the center of cell top surface 15 in the X-axis direction. When gas generated inside exterior body 12 causes the internal pressure of exterior body 12 to reach or exceed a predetermined value, gas exhaust valve 17 exhausts the gas to the outside of exterior body 12. Gas from gas exhaust valve 17 flows through duct 71, which will be described later, and is exhausted to the outside of battery module 1.

[0031] The battery cell 11 further has electrode terminals 16, each of which is a pair of a positive terminal 16P and a negative terminal 16N. The electrode terminals 16 are provided on a cell top surface 15. The positive terminal 16P and the negative terminal 16N are provided on either side of the gas release valve 17 in the X-axis direction.

[0032] The case body 31 has a rectangular parallelepiped appearance. The case body 31 is made of resin. In each battery cell unit 21, the case body 31 houses a plurality of battery cells 11. The case body 31 has a case top 32. The case top 32 has a wall shape with the Z-axis direction being the thickness direction and disposed parallel to the X-axis-Y-axis plane.

[0033] As shown in Fig. 2 and Fig. 3, a plurality of battery cells 11 are stacked in the Y-axis direction (first direction) across the battery cell units 21A to 21F arranged in the Y-axis direction. The plurality of battery cells 11 are stacked such that the cell side surfaces 13 face each other and the cell side surfaces 14 face each other between the battery cells 11 adjacent in the Y-axis direction. As a result, the positive electrode terminals 16P and the negative electrode terminals 16N are alternately arranged in the Y-axis direction in which the plurality of battery cells 11 are stacked. The positive electrode terminals 16P and the negative electrode terminals 16N adjacent in the Y-axis direction are connected to each other by a bus bar (not shown). As a result, the plurality of battery cells 11 are electrically connected to each other in series.

[0034] 1 and 2, the battery module 1 further includes a pair of end plates 42 (42P, 42Q) and a pair of bind bars 43 (restraint members). The pair of bind bars 43 and the pair of end plates 42 integrally hold multiple battery cell units 21 (multiple battery cells 11) aligned in the Y-axis direction.

[0035] The pair of end plates 42 are respectively arranged at both ends of the multiple battery cells 11 (multiple battery cell units 21) in the Y axis direction. The end plate 42P faces the battery cell unit 21A in the Y axis direction, and the end plate 42Q faces the battery cell unit 21F in the Y axis direction.

[0036] The pair of bind bars 43 are disposed at both ends of the stack of battery cells 11 in the X-axis direction (second direction). That is, the pair of bind bars 43 are provided so as to be aligned in the X-axis direction with respect to the multiple battery cell units 21 and the end plates 42. The bind bars 43 extend in the Y-axis direction. An end of the bind bar 43 in the -Y-axis direction is connected to the end plate 42P by a bolt 44. An end of the bind bar 43 in the +Y-axis direction is connected to the end plate 42Q by a bolt 44. The pair of bind bars 43, together with the pair of end plates 42, apply a restraining force in the Y-axis direction to the multiple battery cells 11 (multiple battery cell units 21). Note that a retainer may be further provided that extends in the X-axis direction while intersecting with a duct 71 described later and is connected at both ends to the pair of bind bars 43.

[0037] Stud bolts 45 are attached to the end plates 42. The battery module 1 is fixed to a support mechanism (such as a pack case) via the stud bolts 45.

[0038] The battery module 1 further includes a duct 71 and a cover body 51 .

[0039] The duct 71 is made of resin such as polybutylene terephthalate resin (PBT resin). The duct 71 extends in the Y-axis direction while facing the multiple battery cells 11 (multiple battery cell units 21) in the Z-axis direction (third direction). The duct 71 is an elongated body extending in the Y-axis direction. The duct 71 forms a passage through which gas discharged from the multiple battery cells 11 flows. The duct 71 is attached to the mounting member 30. The mounting member 30 is a member held by the battery cells 11, and in this embodiment, is composed of multiple case bodies 31 arranged in the Y-axis direction.

[0040] The cover body 51 is made of resin. The cover body 51 is provided so as to cover the multiple battery cells 11 in the Z-axis direction. The cover body 51 is provided so as to face the case top 32 of the case body 31 in the Z-axis direction. The cover body 51 is provided so as to further cover the duct 71.

[0041] Fig. 5 is a side view showing the periphery of the contact portion between end plate 42Q and case body 31 of battery cell unit 21F. Figs. 6 and 7 are perspective views showing end plate 42Q. Fig. 8 is a perspective view showing a plate-shaped member 100 constituting end plate 42Q. Fig. 9 is a side view showing end plate 42Q. Fig. 10 is a front view showing end plate 42Q.

[0042] Although one end plate 42Q is shown in FIGS. 5 to 9, the other end plate 42P has substantially the same structure as end plate 42Q.

[0043] 5 to 9, end plate 42Q is composed of two plate-like members 100, 200. Plate-like member 100 has a wave-like shape including a protrusion 110 and a recess 120. Protrusion 110 and recess 120 are formed by bending so as to have continuous curved surfaces without corners. As shown in FIG. 5, protrusion 110 constitutes contact portions 110A, 110B that come into contact with case body 31.

[0044] The plate-like member 100 has flange portions 130, 140 that protrude toward the case body 31 along the Y-axis direction. Gaps are formed between the tips of the flange portions 130, 140 in the Y-axis direction and the case body 31 (A and B in FIG. 5).

[0045] Plate-like member 200 has flange portion 210 that protrudes along the Y-axis direction to the side opposite case body 31, and flange portion 220 that protrudes toward case body 31. A gap is formed between the tip of flange portion 220 in the Y-axis direction and case body 31 (B in FIG. 5).

[0046] In the plate-like member 100, a plurality of protrusions 110 and recesses 120 are alternately formed so as to be aligned in the Z-axis direction. The protrusions 110 and recesses 120 are formed so as to extend in the X-axis direction. A flat surface portion 150 is formed in each of the plurality of recesses 120 (three in the example of Figs. 5 to 9). Fastening holes 44A (fastening portions) penetrating the plate-like members 100, 200 are formed in the flat surfaces 150 located at both ends of the end plate 42Q in the X-axis direction. A bolt 44 for fastening the end plate 42Q and the bind bar 43 is inserted into the fastening hole 44A.

[0047] The flange portions 140, 220 of the plate-like members 100, 200 are provided only in the central portion of the end plate 42Q in the X-axis direction, and are not provided at both ends of the end plate 42Q in the X-axis direction. Therefore, at both ends of the end plate 42Q in the X-axis direction, the flat portions 150, 230 extend to the lower ends of the plate-like members 100, 200 (the tips in the -Z-axis direction).

[0048] Between the flange portion 140 and the flat portion 150 located at the lower end of the plate-shaped member 100, a transition portion 160 is provided that continuously transitions from the flat portion 150 to the flange portion 140. The transition portion 160 is adjacent to the flat portion 150 located at the lower end of the plate-shaped member 100. The transition portion 160 is formed by performing a twist process (twist bending process) on the plate-shaped member 100. Therefore, the plate-shaped member 100 transitions from the flat portion 150 at both ends in the X-axis direction of the end plate 42Q to the flange portion 140 at the center in the X-axis direction of the end plate 42Q so that a curved surface without corners continues. The flat portion 150 located at the lower end of the plate-shaped member 100, the transition portion 160, and the flange portion 140 are provided to be aligned in the X-axis direction (second direction).

[0049] Similarly, between the flange portion 220 and the flat portion 230 located at the lower end of the plate-shaped member 200, a transition portion 240 is provided that continuously transitions from the flat portion 230 to the flange portion 220. The transition portion 240 is adjacent to the flat portion 230 located at the lower end of the plate-shaped member 200. The transition portion 240 is formed by performing a twist process (twist bending process) on the plate-shaped member 200. Therefore, the plate-shaped member 200 transitions so that a curved surface without corners continues from the flat portion 230 at both ends of the X-axis direction of the end plate 42Q to the flange portion 220 at the center of the X-axis direction of the end plate 42Q. The flat portion 230 located at the lower end of the plate-shaped member 100, the transition portion 240, and the flange portion 220 are provided to be aligned in the X-axis direction (second direction).

[0050] The flange portion 140 of the plate-shaped member 100 and the flange portion 220 of the plate-shaped member 200 are formed to be aligned in the Z-axis direction. The flange portion 140 is located on the +Z-axis direction side of the flange portion 220.

[0051] 10, the total length (L1) of the flange portion 140 and the transition portion 160 in the X-axis direction and the total length (L2) of the flange portion 220 and the transition portion 240 in the X-axis direction are smaller than the pitch (L) of the fastening holes 44A in the X-axis direction (L>L1, L2). Therefore, at both ends in the X-axis direction, the areas of the flat portions 150 and 230 where the fastening holes 44A are provided on the lower end side (-Z axis side) can be secured.

[0052] As an example of the dimensions shown in Figs. 9 and 10, L is about 100 mm, L1 is about 90 mm, L2 is about 80 mm, and H1 and H2 are about 5 to 6 mm.

[0053] The widths of the contact portions 110A, 110B extending in the X-axis direction change along the X-axis direction, and each has a wide portion (D1A, D1B) and a narrow portion (D2A, D2B). Between the wide portion and the narrow portion, the widths of the contact portions 110A, 110B change continuously and smoothly (curve-like) as shown in FIG.

[0054] A stud bolt 45 is attached to the end plate 42Q (plate-shaped member 200) on the side opposite to the portion with the wide width (D1A, D1B) shown in Fig. 10. This improves the supporting strength of the battery module 1.

[0055] In the battery module 1 according to one embodiment of the present technology, the plate-like member 100 constituting the end plate 42Q has a corrugated shape including the protrusions 110 and the recesses 120, so that the strength of the end plate 42Q can be improved.

[0056] Furthermore, by providing flange portions 130, 140, 210, 220 that protrude along the Y-axis direction from the upper and lower ends (upper and lower ends in the Z-axis direction) of the plate-like members 100, 20, the strength of the end plate 42Q can be further improved.

[0057] By not providing flange portions 140, 220 at the lower ends at both ends of end plate 42Q in the X-axis direction and by extending flat portions 150, 230 to the lower ends of plate-shaped members 100, 200, the area of ​​flat portions 150, 230 can be secured while suppressing an increase in the height of plate-shaped members 100, 200 in the Z-axis direction, so that miniaturization of end plate 42Q is not hindered.

[0058] In this manner, in the battery module 1, the flange portions 140, 220 (the central portion in the X-axis direction) and the flat portions 150, 230 (both end portions in the X-axis direction) are provided at the lower ends of the plate-shaped members 100, 200. This results in a boundary portion between the flange portions 140, 220 and the flat portions 150, 230. By providing the transition portions 160, 240 that continuously transition from the flat portions 150, 230 to the flange portions 140, 220 at this boundary portion, it is possible to prevent the formation of corners that cause excessive stress concentration in the plate-shaped members 100, 200, and therefore it is possible to connect the flange portions 140, 220 and the flat portions 150, 230, respectively, without impairing the strength of the end plates 42Q.

[0059] As a result of the above, it is possible to reduce the size of the battery module 1 (particularly, to suppress an increase in the dimension in the Z-axis direction) while maintaining the strength of the end plate 42Q.

[0060] Furthermore, in the battery module 1, a battery cell unit 21 is formed by arranging a plurality of battery cells 11 in the Y-axis direction and housing them in a case body 31, and by arranging a plurality of battery cell units 21 in the Y-axis direction to form the battery module 1, the manufacturing process can be simplified compared to when the battery module 1 is manufactured with each of the plurality of battery cells 11 as a single unit.

[0061] In the battery module 1, by configuring the battery cell units 21 in which a plurality of battery cells 11 are housed in a case body 31, the battery module 1 can be easily disassembled or replaced in units of battery cell units 21.

[0062] In the battery module 1, by configuring a battery cell unit 21 in which multiple battery cells 11 are housed in a case body 31, when the battery module 1 is to be disposed of, the battery module 1 can be divided and each battery cell unit 21 can be handled as a single unit at a lower voltage. This makes it easy to dispose of the battery module 1.

[0063] In the battery module 1, one unit contains two or more battery cells 11, and by making the output density of each of the two or more battery cells 11 approximately 8000 W / L or more, a power supply device with a predetermined voltage or higher can be formed on a unit basis.

[0064] Although the embodiment of the present technology has been described above, the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The scope of the present technology is defined by the claims, and it is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0065] 1 battery module, 11 battery cell, 12 exterior body, 13 cell side, 14 cell side, 15 cell top, 16 electrode terminal, 16N negative electrode terminal, 16P positive electrode terminal, 17 gas exhaust valve, 21, 21A, 21B, 21C, 21D, 21E, 21F battery cell unit, 30 mounting member, 31 case body, 32 case top, 42, 42P, 42Q end plate, 43 bind bar, 44 bolt, 44A fastening hole, 45 stud bolt, 51 cover body, 71 duct, 100 plate-shaped member, 110 convex portion, 110A, 110B abutment portion, 120 concave portion, 130, 140 flange portion, 150 flat portion, 160 transition portion, 200 plate-shaped member, 210, 220 Flange section, 230 plane section, 240 transition section.

Claims

1. A plurality of battery cells arranged side by side in a first direction, each of the battery cells having a rectangular shape; an end plate arranged to be aligned with the plurality of battery cells in the first direction; a restraining member that is arranged to be aligned with the plurality of battery cells and the end plates in a second direction perpendicular to the first direction, and that restrains the plurality of battery cells and the end plates along the first direction; The end plate includes a plate-shaped member, the plate-like member includes a planar portion extending in a direction perpendicular to the first direction, a flange portion provided at an end of the plate-like member in a third direction perpendicular to the first direction and the second direction and protruding from the planar portion in the first direction, and a transition portion that transitions continuously from the planar portion to the flange portion such that a curved surface without corners continues on the plate-like member; The flange portion is not provided at both ends of the end plate in the second direction, and the flat portion extends to an end of the plate-like member in the third direction, The planar portion, the transition portion, and the flange portion are aligned in the second direction.

2. The battery module according to claim 1 , wherein the end plate includes a fastening portion provided on the planar portion adjacent to the transition portion and fastened to the restraining member.

3. The battery module according to claim 2 , wherein the fastening portions are provided so as to be located at both ends of the end plates in the second direction.

4. The battery module according to claim 1 , further comprising a case that houses the plurality of battery cells and supports them in at least the first direction, forming a unit including the plurality of battery cells.

5. The battery module according to claim 4 , wherein the plate-like members each have a protrusion and a recess that extend in the second direction and are aligned in the third direction, and the protrusions abut against the case from the first direction.

6. The battery module according to claim 4 , wherein each of the units includes two or more battery cells, and the power density of each of the two or more battery cells is 8000 W / L or more.

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