Battery module
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
- Filing Date
- 2025-11-12
- Publication Date
- 2026-07-30
Smart Images
Figure JP2025039581_30072026_PF_FP_ABST
Abstract
Description
Battery module
[0001] The present disclosure relates to a battery module.
[0002] Patent Document 1 discloses a battery module including a battery block that holds a plurality of battery cells, a cover that covers the battery block, and a duct member that forms a discharge path. The duct member is disposed between the battery block and the end wall of the exterior case within the exterior case.
[0003] When the internal pressure of the battery cell rises, hot gas may be released from the battery cell with sparks. This gas passes in order between the battery block and the cover, between the battery block and the duct member, through the discharge path, and between the duct member and the end wall, and is finally discharged to the outside of the exterior case through the vent hole in the end wall. In order to extinguish the sparks during this process, the discharge path is configured in a labyrinth shape.
[0004] International Publication No. 2020 / 166501
[0005] When gas is released from the battery cell, the battery block may be partially melted by its heat, and some of the battery cells may not be held in place. At this time, the inclined battery cell may directly release gas and sparks into the space between the battery block and the duct member, and the exterior case may be directly exposed to the sparks.
[0006] An object of the present disclosure is to improve the heat protection of the exterior case of the battery module.
[0007] One aspect of the present disclosure provides a battery module comprising: an outer casing; a battery block housed in the outer casing, comprising a plurality of battery cells, each having an end face portion that releases gas in response to an increase in internal pressure; and a battery holder that holds the plurality of battery cells along the height direction such that the end faces face either one or the other side in the height direction of the outer casing; a cover plate that covers the battery block from the one side in the height direction and is interposed between the battery block and the outer casing; and a gas flow path defined by the battery block and the cover plate, which guides the gas released from the battery cells to the one side in the height direction, wherein the cover plate has a projection that protrudes from the battery block to one side in the longitudinal direction of the outer casing.
[0008] According to this disclosure, the thermal protection of the battery module's outer casing can be improved.
[0009] A perspective view of a battery module according to an embodiment. An exploded perspective view of the battery module of Figure 1. A plan view of the battery module, showing the battery module of Figure 1 with the top cover, first cover plate, and duct cover removed. A cross-sectional view of the battery module of Figure 1. A perspective view of the first cover plate of Figure 2, seen from below. A perspective view of the internal structure of the outer casing, showing the battery module of Figure 1 with the outer casing removed. An enlarged view of Figure 6. A plan view of the battery module, showing the battery module of Figure 1 with the top cover removed, i.e., the battery module of Figure 3 with the first cover plate and duct cover attached. An enlarged view of Figure 8. An enlarged view of Figure 4, showing a partial cross-sectional view of the battery module cut along the line X-X in Figure 9. A diagram corresponding to Figure 9 of a modified battery module, showing a partial plan view of the battery module with the top cover removed.
[0010] A battery module according to one embodiment of the present disclosure comprises: an outer casing; a battery block housed in the outer casing, comprising: a plurality of battery cells each having an end face portion that releases gas in response to an increase in internal pressure; a battery holder that holds the plurality of battery cells along the height direction such that the end faces face either one or the other side in the height direction of the outer casing; a cover plate that covers the battery block from the one side in the height direction and is interposed between the battery block and the outer casing; and a gas inlet passage defined by the battery block and the cover plate, which guides the gas released from the battery cells to the one side in the height direction, wherein the cover plate has a projection that protrudes from the battery block to one side in the longitudinal direction of the outer casing.
[0011] With the above configuration, even if the battery cell is tilted, the protruding part can catch the gas and sparks released from the tilted battery cell. This prevents the outer casing from being exposed to sparks.
[0012] In a battery module according to another embodiment of the present disclosure, the plurality of battery cells include a group of end cells held in the battery holder at one end in the longitudinal direction, and the end faces of the group of end cells may be oriented toward the one end in the height direction.
[0013] In this configuration, since there are no other battery cells on one side of the terminal cell group in the longitudinal direction, the terminal cell group is more prone to tilting when it releases gas compared to other battery cells. With the above configuration, even if the terminal cell group tilts due to the gas it releases, causing its end face to tilt to one side in the longitudinal direction, the protruding portion can receive that gas.
[0014] A battery module according to another embodiment of the present disclosure further comprises a duct member adjacent to the battery block on one side in the longitudinal direction within the outer casing, defining a gas discharge passage that communicates with the gas inlet passage, and the protrusion may be in close proximity to and facing the duct member.
[0015] According to the above configuration, the inner surface of the outer casing is covered by the protrusion in the space between the battery block and the duct member. As a result, the thermal protection of the outer casing is improved.
[0016] In a battery module according to another embodiment of the present disclosure, the cover plate has a cover portion that overlaps with the battery block when viewed in the height direction, and the protruding portion may include an extension portion that extends from the cover portion to one side in the longitudinal direction, and a folded portion that extends from the tip of the extension portion to the other side in the height direction.
[0017] With the above configuration, the gas can be contained by the extension and the folded-back section. Even if the battery cell is tilted significantly, the gas and sparks can be contained by the protruding section.
[0018] In a battery module according to another embodiment of the present disclosure, the cover portion and the extension portion may protrude from the folded portion on both sides in the width direction of the outer case.
[0019] According to the above configuration, the folded portion is located in the center of the width direction of the extension. By limiting the length of the folded portion in the width direction in this way, it is possible to prevent the outer casing from being exposed to sparks without obstructing the smooth flow of gas.
[0020] A battery module according to another embodiment of the present disclosure further comprises a duct member adjacent to the battery block on one side in the longitudinal direction within the outer casing and defining a gas discharge passage that communicates with the gas inlet passage, wherein the inlet of the gas discharge passage is located on the outside in the width direction relative to the folded portion.
[0021] According to the above configuration, the gas flows from the gas inlet passage into the space between the battery block and the duct member, and then flows into the discharge passage via the inlet. The inlet is located on the outside in the width direction of the folded section. Therefore, after passing through the gas inlet passage, the gas can flow smoothly into the discharge passage without being obstructed by the folded section.
[0022] In a battery module according to another embodiment of the present disclosure, the plurality of battery cells include a group of end cells held in the battery holder at one end in the longitudinal direction, and the folded portion may correspond to the arrangement area of the end cell group in the width direction.
[0023] According to the above configuration, the widthwise length of the folded portion is limited to correspond to the arrangement area of the end cell group. As a result, it is possible to suppress the exposure of the outer casing to sparks while maintaining a smooth gas flow.
[0024] In a battery module according to another embodiment of the present disclosure, the protrusion may further include a re-folded portion extending from the tip of the folded portion toward the other side in the longitudinal direction.
[0025] According to the above configuration, the tilted battery cell can be supported by the folded-back section, thereby suppressing the tilting of the battery cell.
[0026] The following describes specific examples of this disclosure in detail based on the drawings. In the following description, terms indicating specific directions or positions (e.g., "up," "down," and other terms including these) will be used as needed. The use of these terms is for the purpose of facilitating understanding of the disclosure with reference to the drawings, and the meaning of these terms does not limit the technical scope of this disclosure. Also, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments shown below are examples of the technical concept of this disclosure and do not limit this disclosure to them. In addition, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are intended to be illustrative, and not to limit the scope of this disclosure unless specifically stated. Also, the content described in one embodiment or example is applicable to other embodiments or examples. Furthermore, the size and positional relationships of the components shown in the drawings may be exaggerated for clarity in the explanation.
[0027] The battery module of this disclosure is applicable, for example, to emergency power sources such as battery backup units (BBUs). However, this disclosure does not specify the application of the battery module, and it can be used as a power source for various other electrical devices, such as a power source for a vehicle's drive motor.
[0028] Referring to Figures 1 and 2, the battery module 1 according to this embodiment comprises an outer case 2, a battery block 3, a first cover plate 4, a second cover plate 5, and a pair of duct members 6.
[0029] The outer casing 2 is rectangular in shape, and when viewed in the height direction Z (i.e., in a plan view), it is rectangular. In the following description, the direction in which the longer side of this rectangle extends is called the longitudinal direction X, and the direction in which the shorter side extends is called the width direction Y. The longitudinal direction X, the width direction Y, and the height direction Z are perpendicular to the other two directions.
[0030] The outer casing 2 has a first end wall 21 and a second end wall 22 facing each other in the longitudinal direction X, a bottom wall 23 and a top wall 24 facing each other in the height direction Z, and a first side wall 25 and a second side wall 26 facing each other in the width direction Y. The outer casing 2 defines the internal space enclosed by these walls.
[0031] The first end wall 21 extends upward from the end of the bottom wall 23 on one side in the longitudinal direction X (upper right side in Figure 2) and connects to the end of the top wall 24. The second end wall 22 connects the ends of the bottom wall 23 and the top wall 24 on the other side in the longitudinal direction X (lower left side in Figure 2). The first side wall 25 connects the first end wall 21 and the second end wall 22 on one side in the width direction Y (upper left side in Figure 2). The second side wall 26 connects the first end wall 21 and the second end wall 22 on the other side in the width direction Y (lower right side in Figure 2).
[0032] The outer casing 2 has a first vent 27 provided in the first end wall 21 and a second vent 28 provided in the second end wall 22. Both the first vent 27 and the second vent 28 are composed of multiple through holes, connecting the inside and outside of the outer casing 2. The first vent 27 and the second vent 28 allow air to pass through for air cooling of the electrical components housed in the outer casing 2. There is no particular limitation on which is the inlet side. In addition, both the first vent 27 and the second vent 28 discharge gas released from the battery cell 31 into the inside of the outer casing 2 to the outside of the outer casing 2.
[0033] The outer casing 2 has a base 2A and a cover 2B as its components, which are separable in the height direction Z. The base 2A constitutes at least the bottom wall 23. The cover 2B constitutes at least the top wall 24.
[0034] In this embodiment, the outer case 2 further includes a first end plate 2C that constitutes a first end wall 21 and a second end plate 2D that constitutes a second end wall 22 as its components. Both the base 2A and the cover 2B are U-shaped when viewed in the longitudinal direction X and have a pair of side walls. When assembling the battery module 1, first the first end plate 2C and the second end plate 2D are fastened to the side walls of the base 2A, and the contents such as the battery block 3 are assembled to the base 2A. Then the cover 2B is placed over the base 2A from above, and the side walls of the base 2A are covered by the side walls of the cover 2B. On one side in the width direction Y, the side wall of the cover 2B is fastened to the side wall of the base 2A, forming the first side wall 25. The second side wall 26 is formed in the same manner on the other side.
[0035] However, the parts division of the outer case 2 can be changed as appropriate. The first end wall 21 may be integrated with the base 2A or the cover 2B. The same applies to the second end wall 22. The first side wall 25 may be made up of the base 2A alone or the cover 2B alone. The same applies to the second side wall 26.
[0036] Referring to Figure 2, the internal space of the outer casing 2 includes a battery arrangement space 2a that houses the battery block 3. The internal space of the outer casing 2 further includes, on one side in the longitudinal direction X as viewed from the battery arrangement space 2a, a first gap 2b between the battery block 3 and the duct member 6, a first duct arrangement space 2c that houses the duct member 6, and a first end space 2d between the duct member 6 and the first end wall 21. The internal space of the outer casing 2 further includes, on the other side in the longitudinal direction X as viewed from the battery arrangement space 2a, a second gap 2e between the battery block 3 and the duct member 6, a second duct arrangement space 2f that houses the duct member 6, and a second end space 2g between the duct member 6 and the second end wall 22.
[0037] In the battery placement space 2a, the first cover plate 4 covers the battery block 3 from above and is interposed between the battery block 3 and the top wall 24 of the outer case 2. The second cover plate 5 covers the battery block 3 from below and is interposed between the battery block 3 and the bottom wall 23 of the outer case 2.
[0038] Referring to Figures 2 to 4, the battery block 3 comprises a plurality of battery cells 31 and a battery holder 32. The battery block 3 is generally rectangular in shape and holds the plurality of battery cells 31.
[0039] The battery cell 31 is, for example, a non-aqueous electrolyte secondary battery such as a lithium-ion battery, and has a cylindrical container. However, the battery cell 31 may be a battery other than a cylindrical shape, such as a prismatic battery, or a battery other than a lithium-ion battery, such as an all-solid-state battery.
[0040] The battery cell 31 has a discharge valve that opens when the internal pressure of the container exceeds a set pressure. This allows the high pressure to be released and prevents the container from rupturing. When the discharge valve opens, high-temperature gas is released from the battery cell 31. The gas may be accompanied by sparks.
[0041] In the case of a cylindrical shape, the battery cell 31 has circular first end faces 31a and second end faces 31b at both axial ends. The discharge valve is provided on the first end face 31a. The battery cell 31 has a first electrode located on the first end face 31a and a second electrode located on the second end face 31b. Typically, the first electrode is the positive electrode and the second electrode is the negative electrode, but the polarities may be reversed.
[0042] The battery holder 32 is molded from an insulating material, for example, a thermoplastic resin. The battery holder 32 has a plurality of cell accommodating portions 32a for holding a plurality of battery cells 31 in fixed positions. Each cell accommodating portion 32a has a shape complementary to the battery cell 31 (cylindrical shape in this example) and accommodates one battery cell 31. The plurality of battery cells 31 are held in a posture with the axial direction facing the height direction Z and are arranged in a staggered pattern within the plane of the longitudinal direction X and the width direction Y.
[0043] The plurality of battery cells 31 constitute a plurality of parallel units 10 arranged in the longitudinal direction X. In each parallel unit 10, two or more battery cells 31 are connected in parallel to each other, and the plurality of parallel units 10 are sequentially connected in series. Such electrical connection between the battery cells 31 is realized by a current collecting structure (not shown). The current collecting structure is constituted by a plurality of lead plates arranged in the longitudinal direction X.
[0044] As an example, a double-sided current collecting method dispersed on both the upper and lower sides of the battery holder 32 is applied to the current collecting structure. In the double-sided current collecting method, some of the battery cells 31 are held by the battery holder 32 with the first end face facing upward, and the remaining battery cells 31 are held by the battery holder 32 with the first end face 31a facing downward. Also, some of the lead plates are overlapped on the upper surface of the battery holder 32 and connected to the electrodes of the battery cells 31 with the first end face 31a facing upward. The remaining lead plates are overlapped on the lower surface of the battery holder 32 and connected to the electrodes of the battery cells 31 with the first end face 31a facing downward.
[0045] In the zigzag arrangement of the present embodiment, 70 battery cells 31 form 28 cell rows 15 arranged at intervals in the longitudinal direction X. In each cell row 15, two or three battery cells 31 are arranged at intervals in the width direction Y. The plurality of cell rows 15 include a first cell row 16 composed of two battery cells 31 and a second cell row 17 composed of three battery cells 31, and the first cell row 16 and the second cell row 17 are alternately arranged in the longitudinal direction X. The battery cells 31 in the first cell row 16 and the battery cells 31 in the second cell row 17 are arranged so as to be offset from each other in the width direction Y.
[0046] In the double-sided current collection method of the present embodiment, one row of the first cell row 16 and one row of the second cell row 17 constitute one parallel unit 10. One parallel unit 10 is composed of five battery cells 31 connected in parallel to each other, and 70 battery cells 31 constitute 14 parallel units 10. The five battery cells 31 forming the same parallel unit have their first end faces 31a facing the same side in the height direction Z. The plurality of parallel units 10 include a first parallel unit 11 with its first end face 31a facing upward and a second parallel unit 12 with its first end face 31a facing downward, and the first parallel unit 11 and the second parallel unit 12 are alternately arranged in the longitudinal direction X.
[0047] Further, the plurality of battery cells 31 include a first end cell group 31A held by a battery holder 32 at one end on the one side in the longitudinal direction X. In the present embodiment, the first end cell group 31A is the first cell row 16 and is composed of two battery cells 31. At one end on the one side in the longitudinal direction X, the first parallel unit 11 is provided. The first end cell group 31A has its first end face 31a facing upward.
[0048] In addition, the plurality of battery cells 31 include a second end cell group 31B held by a battery holder 32 at the other end on the other side in the longitudinal direction X. In the present embodiment, the second end cell group 31B is the second cell row 17 and is composed of three battery cells 31. Since the number of parallel units 10 is even, the second parallel unit 12 is provided at the other end on the other side in the longitudinal direction X. The second end cell group 31B has its first end face 31a facing downward.
[0049] A battery cell 31 with its first end face 31a facing upward releases gas upward. The upper side of the battery block 3 is covered by a first cover plate 4. The first cover plate 4 and the upper surface of the battery block 3 define a first gas inlet passage 49 that guides the gas released upward from the battery cell 31. A battery cell 31 with its first end face 31a facing downward releases gas downward. The lower side of the battery block 3 is covered by a second cover plate 5. The second cover plate 5 and the lower surface of the battery block 3 define a second gas inlet passage 59 that guides the gas released downward from the battery cell 31. Both the first gas inlet passage 49 and the second gas inlet passage 59 are open at both ends in the longitudinal direction X and communicate with both the first gap 2b and the second gap 2e.
[0050] One duct member 6 is adjacent to the battery block 3 on one side in the longitudinal direction X and defines a gas discharge passage 60 that communicates with the first gas inlet passage 49 and the second gas inlet passage 59 via a first gap 2b. The duct member 6 is supported on the inner surface of the bottom wall 23 and extends in the height direction Z. The duct member 6 comprises a partition wall 61 that separates the first gap 2b and the first end space 2d, a labyrinth wall 62 that defines a labyrinth-shaped gas discharge passage 60 together with the partition wall 61, and a duct cover 63 that covers the labyrinth wall 62 from above. The inlet 60a of the gas discharge passage 60 is located off-center on one side in the width direction Y and opens to the first gap 2b. The outlet 60b of the gas discharge passage 60 opens to the first end space 2d.
[0051] The other duct member 6 has a similar structure to the first duct member 6, and the pair of duct members 6 are arranged point-symmetrically about the axis in the height direction Z. The other duct member 6 is adjacent to the battery block 3 on the other side in the longitudinal direction X and defines a gas discharge passage 60 that communicates with the first gas inlet passage 49 and the second gas inlet passage 59 via a second gap 2e. The inlet 60a of the gas discharge passage 60 is open to the second gap 2e, and the outlet 60b of the gas discharge passage 60 is open to the second end space 2g.
[0052] Referring to Figures 2 and 5, a portion of the gas in the first gas inlet passage 49 flows to one side in the longitudinal direction X and flows into the first gap 2b. A portion of the gas in the first gas inlet passage 49 flows to the other side in the longitudinal direction X and flows into the second gap 2e. The battery cell 31 (a battery cell 31 constituting the first parallel unit 11) with its first end face 31a facing downwards releases gas downward, and this gas flows into the second gas inlet passage 59. The gas in the second gas inlet passage 59 also flows in the longitudinal direction X and flows into either the first gap 2b or the second gap 2e. The gas in the first gap 2b passes sequentially through the gas discharge passage 60 and the first end space 2d and is discharged to the outside of the outer casing 2 via the first vent 27. The gas in the second gap 2e passes sequentially through the gas discharge passage 60 and the second end space 2g and is discharged to the outside of the outer casing 2 via the second vent 28.
[0053] Referring to Figures 6 to 10, the first cover plate 4 has a cover portion 41 that overlaps with the battery block 3 when viewed in the height direction Z, and a projection portion 42 that protrudes to one side in the longitudinal direction X relative to the battery block 3. The projection portion 42 includes an extension portion 43 that extends from the cover portion 41 to one side in the longitudinal direction X, a folded portion 44 that extends downward from the tip of the extension portion 43, and a further folded portion 45 that extends from the tip of the folded portion 44 toward the other side in the longitudinal direction X.
[0054] The cover portion 41 and the extension portion 43 are a single flat plate, and are rectangular in shape with an elongated length in the longitudinal direction X when viewed in the height direction Z. The cover portion 41 is located in the battery placement space 2a. The extension portion 43 (protruding portion 42) is located in the first gap 2b.
[0055] The protruding portion 42 is in close proximity to the duct member 6. In this respect, the duct cover 63 is rectangular in shape when viewed in the height direction Z, with its long side extending in the width direction Y and its short side facing in the longitudinal direction X. The width of the duct cover 63 is approximately equal to the distance between the inner surfaces of the first side wall 25 and the second side wall 26. In the first duct arrangement space 2c, the inner surface of the top wall 24 is covered by the duct cover 63 over almost its entire surface. One end of the extension portion 43 in the longitudinal direction X is in close proximity to the other end of the duct cover 63 in the longitudinal direction X.
[0056] The edges of the cover portion 41 on both sides in the width direction Y are linearly extended to one side in the longitudinal direction X. The width of the cover portion 41 and the extension portion 43 are also approximately equal to the distance between the inner surfaces of the first side wall 25 and the second side wall 26, similar to the duct cover 63. Therefore, even in the battery placement space 2a, the inner surface of the top wall 24 is covered by the duct cover 63 over almost its entire length. Furthermore, even in the first gap 2b, the inner surface of the top wall 24 is covered by the duct cover 63 over almost its entire length in both the longitudinal direction X and the width direction Y.
[0057] The cover portion 41 and the extension portion 43 protrude from both sides of the width direction Y of the outer case 2 relative to the folded portion 44. In other words, the folded portion 44 is located in the center of the extension portion 43 in the width direction Y.
[0058] The folded portion 44 corresponds to the arrangement area of the first terminal cell group 31A in the width direction Y. The first terminal cell group 31A consists of two battery cells 31 arranged in the width direction Y. In this embodiment, the "arrangement area" is the area between one end and the other end of each battery cell 31 in the width direction Y. The folded portion 44 is single and covers two arrangement areas. One end edge of the single folded portion 44 in the width direction Y is located to one side of one end of the battery cell 31 on the other side of the width direction Y. The other end edge of the single folded portion 44 in the width direction Y is located to the other side of the other end of the battery cell 31 on the other side of the width direction Y.
[0059] The folded portion 44 is bent at approximately a right angle at the tip of the extension portion 43 and extends downward. The re-folded portion 45 is bent at approximately a right angle at the tip of the folded portion 44 and extends downward. The width of the re-folded portion 45 is approximately equal to the width of the folded portion 44. The folded portion 44 and the re-folded portion 45 are in an inverted L shape when viewed in the width direction Y. The extension portion 43, the folded portion 44, and the re-folded portion 45 define a recess 46 that is open on the other side in the longitudinal direction X. The recess 46 is also open on both sides in the width direction Y.
[0060] The inlet 60a of the gas discharge passage 60 is located on the outside in the width direction Y relative to the folded portion 44. In this embodiment, the inlet 60a is biased to one side in the width direction Y. The inlet 60a is located on one side in the width direction Y relative to one end edge of the folded portion 44 in the width direction Y.
[0061] Here, we assume that the internal pressure of the battery cells 31 constituting the first terminal cell group 31A increases. The gas is released upward, sometimes accompanied by sparks, and flows into the first gas inlet passage 49. The sparks collide with the first cover plate 4. In the battery arrangement space 2a, the top wall 24 is prevented from being directly exposed to the high-temperature gas and sparks.
[0062] Gas flows from the first gas inlet passage 49 into the first gap 2b. The area where the first terminal cell group 31A is located is provided with a bend 44 and a second bend 45, and gas may flow into the recess 46 defined by these bend 44 and second bend 45. However, the bend 44 is located in the center of the extension 43, and the recess 46 is open on both sides in the width direction Y. Even if gas flows into the recess 46, it can be smoothly discharged from the recess 46. Furthermore, the inlet 60a of the gas discharge passage 60 is located outside the width direction Y when viewed from the recess 46. Therefore, the gas that has flowed out of the recess 46 is smoothly introduced into the gas discharge passage 60.
[0063] If the temperature of the gas leaking from the first terminal cell group 31A is very high, and / or if the gas leaking from the first terminal cell group 31A is accompanied by a large amount of sparks, it is possible that the resin battery holder 32 may melt due to the heat of the gas and sparks. There are no other cell housings or battery cells on one side of the longitudinal direction X of the first terminal cell group 31A. Therefore, if the battery holder 32 melts due to the gas and sparks released from the first terminal cell group 31A, there will be nothing to support the first terminal cell group 31A, and the battery cells 31 may tip over. The discharge valve of the first terminal cell group 31A is oriented upwards, and therefore the upper part of the battery holder 32 is prone to melting. In this case, compared to the case where the discharge valve is oriented downwards, as in the second terminal cell group 31B, the battery cells 31 are considered to be more likely to tilt.
[0064] When the battery cell 31 of the first terminal cell group 31A tilts, the first end face tilts downward to one side in the longitudinal direction X from its fixed position. As the axis of the battery cell 31 tilts, the gas is released upward and toward one side in the longitudinal direction X within the first gap 2b. In this embodiment, the protruding portion 42 (extension portion 43) of the first cover plate 4 covers almost the entire top wall 24 even within the first gap 2b. Therefore, even if the battery cell 31 tilts and gas is ejected diagonally from that battery cell 31 into the first gap 2b, the top wall 24 is prevented from being directly exposed to the gas and sparks.
[0065] Furthermore, a re-folded portion is provided corresponding to the arrangement area of the first terminal cell group 31A. Even if the battery cell 31 is tilted, the tilt stops when the battery cell 31 abuts against the re-folded portion 45. This prevents situations in which gas is ejected from the battery cell 31 in a nearly horizontal direction.
[0066] Although embodiments have been described above, the above configuration is merely an example and can be modified as appropriate within the scope of this disclosure.
[0067] As shown in Figure 11, multiple folded portions 44 may be provided corresponding to the arrangement area of each of the multiple battery cells 31. In this case, multiple re-folded portions 45 may be provided for each of the multiple folded portions 44. However, this is just one example, and a single folded portion 44 as in the above embodiment may be combined with multiple re-folded portions 45 corresponding to each of the multiple battery cells 31 as shown in Figure 11.
[0068] A protrusion may be provided at one end of the second cover plate 5 in the longitudinal direction X, similar to the one end of the first cover plate 4. A protrusion may also be provided at the other end of the first cover plate 4 in the longitudinal direction X, and at the other end of the second cover plate 5 in the longitudinal direction X, similar to the one end of the first cover plate 4 in the longitudinal direction X.
[0069] In the above embodiment, the folded portion 44 is approximately perpendicular to the extension portion 43. The folded portion 44 may also be at an acute angle to the extension portion 43, and may be inclined toward the other side of the longitudinal direction X as it moves downward from the tip of the extension portion 43. In this case, the re-folded portion 45 may be provided at the tip of the folded portion 44, or it may be omitted.
[0070] This disclosure may include the following disclosures: (Aspect 1) A battery module comprising: an outer casing; a battery block housed in the outer casing, comprising: a plurality of battery cells, each having an end face portion that releases gas in response to an increase in internal pressure; a battery holder that holds the plurality of battery cells along the height direction such that the end faces face either one or the other side in the height direction of the outer casing; a cover plate that covers the battery block from the one side in the height direction and is interposed between the battery block and the outer casing; and a gas inlet passage defined by the battery block and the cover plate, which guides the gas released from the battery cells to the one side in the height direction, wherein the cover plate has a projection that protrudes from the battery block to one side in the longitudinal direction of the outer casing. (Aspect 2) The battery module according to Aspect 1, wherein the plurality of battery cells include a group of end cells held in the battery holder at one end in the longitudinal direction, and the end faces of the group of end cells are oriented toward the one end in the height direction. (Aspect 3) The battery module according to Aspect 1 or 2, further comprising a duct member adjacent to the battery block on one side in the longitudinal direction within the outer case, defining a gas discharge passage communicating with the gas inlet passage, and the protruding portion is in close proximity to the duct member. (Aspect 4) The battery module according to any one of Aspects 1 to 3, wherein the cover plate has a cover portion that overlaps with the battery block when viewed in the height direction, and the protruding portion includes an extension portion extending from the cover portion toward the one end in the longitudinal direction, and a folded portion extending from the tip of the extension portion toward the other end in the height direction. (Aspect 5) The battery module according to aspect 4, wherein the cover portion and the extension portion protrude from both sides in the width direction of the outer case relative to the folded portion. (Aspect 6) The battery module according to aspect 5, further comprising a duct member adjacent to one side in the longitudinal direction of the battery block within the outer case and defining a gas discharge passage that communicates with the gas inlet passage, wherein the inlet of the gas discharge passage is located on the outside in the width direction relative to the folded portion.(Aspect 7) The battery module according to aspect 5 or 6, wherein the plurality of battery cells include a group of end cells held in the battery holder at one end in the longitudinal direction, and the folded portion corresponds to the arrangement area of the end cell group in the width direction. (Aspect 8) The battery module according to any one of aspects 4 to 7, wherein the protruding portion further includes a re-folded portion extending from the tip of the folded portion toward the other side in the longitudinal direction.
[0071] 1 Battery module 2 Outer case 2A Base 2B Cover 2C First end plate 2D Second end plate 2a Battery placement space 2b First gap 2c First duct placement space 2d First end space 2e Second gap 2f Second duct placement space 2g Second end space 3 Battery block 4 First cover plate 5 Second cover plate 6 Duct member 10 Parallel unit 11 First parallel unit 12 Second parallel unit 15 Cell row 16 First cell row 17 Second cell row 21 First end wall 22 Second end wall 23 Bottom wall 24 Top wall 25 First side wall 26 Second side wall 27 First vent 28 Second vent 31 Battery cell 31A First end cell group 31B Second end cell group 31a First end face 31b Second end face 32 Battery holder 32a Cell housing section 41 Cover section 42 Protruding section 43 Extension section 44 Folded section 45 Re-folded section 46 Recess 49 First gas inlet passage 59 Second gas inlet passage 60 Gas outlet passage 60a Inlet 60b Outlet 61 Partition wall 62 Labyrinth wall 63 Duct cover X Longitudinal direction Y Width direction Z Height direction
Claims
1. A battery module comprising: an outer casing; a battery block housed in the outer casing, comprising: a plurality of battery cells, each having an end face portion that releases gas in response to an increase in internal pressure; a battery holder that holds the plurality of battery cells along the height direction such that the end faces face either one or the other side in the height direction of the outer casing; a cover plate that covers the battery block from the one side in the height direction and is interposed between the battery block and the outer casing; and a gas inlet passage defined by the battery block and the cover plate, which guides the gas released from the battery cells to the one side in the height direction, wherein the cover plate has a projection that protrudes from the battery block to one side in the longitudinal direction of the outer casing.
2. The battery module according to claim 1, wherein the plurality of battery cells include a group of end cells held in the battery holder at one end in the longitudinal direction, and the end faces of the group of end cells are oriented toward the one end in the height direction.
3. The battery module according to claim 1 or 2, further comprising a duct member adjacent to the battery block on one side in the longitudinal direction within the outer casing, defining a gas discharge passage that communicates with the gas inlet passage, wherein the protruding portion is in close proximity to and facing the duct member.
4. The battery module according to claim 1, wherein the cover plate has a cover portion that overlaps with the battery block when viewed in the height direction, and the protruding portion includes an extension portion that extends from the cover portion to one side in the longitudinal direction, and a folded portion that extends from the tip of the extension portion to the other side in the height direction.
5. The battery module according to claim 4, wherein the cover portion and the extension portion protrude from the folded portion on both sides in the width direction of the outer case.
6. The battery module according to claim 5, further comprising a duct member adjacent to the battery block on one side in the longitudinal direction within the outer casing, defining a gas discharge passage that communicates with the gas inlet passage, wherein the inlet of the gas discharge passage is located outward in the width direction relative to the folded portion.
7. The battery module according to claim 5, wherein the plurality of battery cells include a group of end cells held in the battery holder at one end in the longitudinal direction, and the folded portion corresponds to the arrangement area of the end cell group in the width direction.
8. The battery module according to any one of claims 4 to 7, wherein the protruding portion further includes a re-folded portion extending from the tip of the folded portion toward the other side in the longitudinal direction.