Battery module

Abstract

A battery module (1) comprises: a first vent hole (27) that is provided in a first end wall (21) of an exterior case (2); a battery block (3) that holds a plurality of battery cells (31); a first duct member (4) that is disposed between the battery block (3) and the first end wall (21), and defines a labyrinth-shaped discharge path (40) for guiding gas released from the battery cells (31); a connector (7) that is attached to the first end wall (21) of the exterior case (2); a cable (8) that passes through the discharge path (40), and connects the battery block (3) to the connector (7); and one or more protrusions (9) that project into the discharge path (40).

Description

Battery module

[0001] The present disclosure relates to a battery module.

[0002] Patent Document 1 discloses a battery module including a battery block holding a plurality of battery cells and an exterior case housing the battery block. In this battery module, when the internal pressure of the battery cell exceeds the set pressure, gas is discharged from the battery cell with a spark. The gas is discharged to the outside of the exterior case through a vent provided in the end wall of the exterior case.

[0003] A labyrinthine discharge path is provided between the battery block and the end wall. In this discharge path, the gas advances while changing its flow direction and hits a collision plate on the way. The collision plate is expected to cool the gas and extinguish the spark by absorbing energy from the gas.

[0004] A connector is attached to the end wall of the exterior case, and the battery cell is connected to the connector via a lead wire. In order to guide the gas, the arrangement space of the battery block communicates with the arrangement space of the connector through the discharge path. Therefore, the lead wire also passes through the discharge path.

[0005] International Publication No. 2020 / 166501

[0006] It is difficult to accommodate the lead wire in the labyrinthine discharge path. Even if the lead wire is bent and pushed in, the lead wire tends to return to its original shape. If the lead wire protrudes from the discharge path, it will interfere with the subsequent assembly work. On the other hand, if the discharge path is widened, the wiring may be facilitated, but there is a possibility that the gas temperature cannot be sufficiently lowered.

[0007] An object of the present disclosure is to provide a battery module capable of achieving both a decrease in gas temperature and facilitation of wiring work.

[0008] One aspect of the present disclosure provides a battery module comprising: an outer casing; a ventilation opening provided in the end wall of the outer casing; a battery block housed in the outer casing and holding a plurality of battery cells; a duct member housed in the outer casing and positioned between the battery block and the end wall, defining a labyrinthine discharge passage for guiding gas released from the battery cells; a connector attached to the end wall of the outer casing; a cable connecting the battery block to the connector and passing through the discharge passage; and one or more protrusions projecting into the discharge passage.

[0009] According to this disclosure, it is possible to provide a battery module that can achieve both a reduction in gas temperature and simplification of wiring work.

[0010] A perspective view of the battery module according to the embodiment. An exploded perspective view of the battery module of Figure 1. A plan view of the internal structure of the outer case, showing the battery module of Figure 1 with the outer cover and closure plate removed. A perspective view of the internal structure of Figure 3. A perspective view of the internal structure of Figure 4 with the cables omitted. An exploded perspective view of the duct member of Figure 5. A perspective view of the duct member of Figure 5.

[0011] A battery module according to one embodiment of the present disclosure comprises an outer casing, a ventilation opening provided in the end wall of the outer casing, a battery block housed in the outer casing and holding a plurality of battery cells, a duct member housed in the outer casing and positioned between the battery block and the end wall, defining a labyrinthine discharge passage for guiding gas released from the battery cells, a connector attached to the end wall of the outer casing, a cable passing through the discharge passage and connecting the battery block to the connector, and one or more protrusions projecting into the discharge passage.

[0012] According to the above configuration, one or more protrusions extend into the discharge passage. The gas and sparks collide with the protrusions, resulting in a decrease in gas temperature and the extinguishing of the sparks. Furthermore, by securing the cable to the protrusions, deformation of the cable can be suppressed.

[0013] In a battery module according to another embodiment of the present disclosure, the cable may pass below the projection.

[0014] After pushing the cable into the discharge channel, it may deform and spring back up. With the above configuration, this deformation can be suppressed by the underside of the protrusion.

[0015] In a battery module according to another embodiment of the present disclosure, the plurality of protrusions may be arranged at intervals along the direction of gas flow.

[0016] With the above configuration, the gas and sparks are more likely to collide with one of the protrusions as they pass through the discharge passage, making it easier to achieve a decrease in gas temperature and extinguish the sparks. In addition, multiple protrusions are secured to the cable along the flow direction, making it easier to keep the cable contained within the discharge passage.

[0017] In a battery module according to another embodiment of the present disclosure, the plurality of protrusions may include downstream end protrusions located at the downstream end in the flow direction, and the downstream end protrusions may protrude out of the outlet of the discharge passage.

[0018] With the above configuration, the gas and spark can collide with the projection at the outlet, thereby lowering the gas temperature in the discharge passage and extinguishing the spark. The cable is secured to the projection at the outlet of the discharge passage, making it easy to maintain the cable within the discharge passage.

[0019] In a battery module according to another embodiment of the present disclosure, the lower surfaces of the plurality of protrusions may become higher as they move downstream in the flow direction.

[0020] According to the above configuration, the cable can be routed upwards as it moves downstream in the flow direction within the discharge channel.

[0021] In a battery module according to another embodiment of the present disclosure, the discharge passage includes a return passage that reverses the direction of gas flow, and at least one of the plurality of protrusions may protrude into the return passage.

[0022] In the return path, the cable is bent more sharply, making it prone to deformation as it tries to return to its original shape. With the above configuration, the cable is secured to the projection in the return path of the discharge path, making it easier to maintain the state in which the cable is contained within the discharge path.

[0023] 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.

[0024] 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.

[0025] 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 duct member 4, a second duct member 5, and a substrate block 6.

[0026] 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.

[0027] 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.

[0028] 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).

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] Referring to Figure 2, the first duct member 4, the substrate block 6, the battery block 3, and the second duct member 5 are arranged in this order from one side to the other in the longitudinal direction X and housed in the outer case 2.

[0034] 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 first duct member 4, a first duct arrangement space 2c that houses the first duct member 4, and a first end space 2d between the first duct member 4 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 second duct member 5, a second duct arrangement space 2f that houses the second duct member 5, and a second end space 2g between the second duct member 5 and the second end wall 22. The second duct member 5 is close to the battery block 3, while the substrate block 6 is interposed between the battery block 3 and the first duct member 4. Accordingly, the first gap 2b is longer in the longitudinal direction X than the second gap 2e.

[0035] The battery block 3 comprises a plurality of battery cells 31, a battery holder 32, a current collection structure 33, and a cover plate 34. The battery block 3 is generally rectangular in shape and holds the plurality of battery cells 31.

[0036] 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.

[0037] 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.

[0038] In the case of a cylindrical type, the battery cell 31 has a circular first end face and a circular second end face at both axial ends. The discharge valve is provided on the first end face. The battery cell 31 has a first electrode located on the first end face and a second electrode located on the periphery of the first electrode or on the second end face. Typically, the first electrode is the positive electrode and the second electrode is the negative electrode, but the polarity may be reversed.

[0039] The battery holder 32 is molded from an insulating material, such as a thermoplastic resin. The battery holder 32 holds a plurality of battery cells 31 in place. The plurality of battery cells 31 are held in an orientation with their axial direction oriented in the height direction Z, and are arranged in a staggered pattern in the planes of the longitudinal direction X and the width direction Y.

[0040] Multiple battery cells 31 form multiple parallel units arranged in the longitudinal direction X. In each parallel unit, two or more battery cells 31 are connected in parallel to each other, and multiple parallel units are sequentially connected in series.

[0041] The current collection structure 33 enables electrical connection between the battery cells 31. The current collection structure 33 is composed of multiple lead plates (not shown) arranged in the longitudinal direction X. In the illustrated example, the current collection structure 33 employs a double-sided current collection system in which current collection plates are distributed on both the upper and lower sides of the battery holder 32.

[0042] In the double-sided current collection system, some of the battery cells 31 are held in the battery holder 32 with their first end faces facing upward, and the remaining battery cells 31 are held in the battery holder 32 with their first end faces facing downward. Some of the lead plates are placed on the upper surface of the battery holder 32 and connected to the electrodes of the battery cells 31 with their first end faces facing upward. The remaining lead plates are placed on the lower surface of the battery holder 32 and connected to the electrodes of the battery cells 31 with their first end faces facing downward.

[0043] The cover plate 34 is interposed between the battery holder 32 and the exterior case 2, and covers the first end face portion provided with the discharge valve together with the electrode. The cover plate 34 and the battery holder 32 define a gas inflow path (not shown) for guiding the gas released from the battery cell 31. The gas inflow path is open at both ends in the longitudinal direction X. The lead plate of the current collecting structure 33 is disposed between the battery holder 32 and the cover plate 34.

[0044] The battery cell 31 with the first end face portion facing upward discharges gas upward, and the battery cell 31 with the first end face portion facing downward discharges gas downward. Therefore, two cover plates 34 are provided in the battery block 3. The upper cover plate 34 covers the upper surface of the battery holder 32 and is interposed between the battery holder 32 and the top wall 24. The lower cover plate 34 covers the lower surface of the battery holder 32 and is interposed between the battery holder 32 and the bottom wall 23.

[0045] Note that the current collecting structure 33 may adopt a single-sided current collecting method aggregated on the upper side or the lower side of the battery holder 32. In this case, all the battery cells 31 are held in the battery holder 32 with the first end face portion facing upward (or downward). All the lead plates are stacked on the upper surface (or the lower surface) of the battery holder 32 and connected to the electrodes of the battery cells 31. One cover plate 34 is provided in the battery block 3. The cover plate 34 covers the surface of the battery holder 32 on the side where the current collecting structure 33 is disposed, among the upper surface and the lower surface of the battery holder 32.

[0046] The first duct member 4 is disposed between the battery block 3 and the first end wall 21, and more specifically, between the substrate block 6 and the first end wall 21. The first duct member 4 defines a pair of discharge paths 40 for guiding the gas released from the battery cells 31 on both sides in the width direction Y. The inlet 40a of the discharge path 40 is open to the first gap 2b. The outlet 40b of the discharge path 40 is open to the first end space 2d.

[0047] The second duct member 5 is disposed between the battery block 3 and the second end wall 22. The second duct member 5 also defines a pair of discharge paths 50 for guiding the gas released from the battery cells 31 on both sides in the width direction Y. The inlet of the discharge path 50 is open to the second gap 2e. The outlet of the discharge path 50 is open to the second end space 2g.

[0048] The gas released from the battery cell 31 flows into a gas inflow path (not shown). A part of the gas flows along the gas inflow path toward one side in the longitudinal direction X, passes through the first gap 2b, the pair of discharge paths 40, and the first end space 2d in sequence, and is discharged to the outside of the outer case 2 through the first vent 27. Also, a part of the gas flows along the gas inflow path toward the other side in the longitudinal direction X, passes through the second gap 2e, the pair of discharge paths 50, and the second end space 2g in sequence, and is discharged to the outside of the outer case 2 through the second vent 28.

[0049] All four discharge paths (the pair of discharge paths 40 and the pair of discharge paths 50) are labyrinthine. In each of the discharge paths 40 and 50, the flow direction of the gas is changed a plurality of times. At the time of this change, the gas collides with the duct member (the first duct member 4 or the second duct member 5), thereby reducing the thermal energy and kinetic energy of the gas. As a result, the temperature of the gas decreases in the discharge path, and the spark disappears in the discharge path. Therefore, it is possible to suppress the discharge of the high-temperature gas and the spark to the outside of the outer case 2.

[0050] The substrate block 6 includes a substrate holder 61 and one or more circuit boards 62. The substrate holder 61 is formed of an insulating material, for example, a thermoplastic resin. The circuit board 62 is fixed to the substrate holder 61.

[0051] Referring to FIGS. 2 to 4, the battery module 1 further includes a plurality of connectors 7 and a plurality of cables 8. The plurality of connectors 7 are attached to the first end wall 21. The connector 7 has an outer protruding portion that protrudes outside the outer case 2 and an inner protruding portion that protrudes inside the outer case 2 (particularly, the first end space 2d). The outer protruding portion has a structure that can be connected to a connector connected to an external device. The cable 8 passes from the first gap 2b through the discharge path 40 and the first end space 2d and is connected to the inner protruding portion of the connector 7. The cable 8 has a conductor made of a metal wire and a protective film made of an insulating material that covers the conductor, and has flexibility.

[0052] Connector 7 includes a power connector 71 and a communication connector 72. Cable 8 includes a positive and negative pair of lead wires 81 and 82, a signal line 83, and a communication line 84. The lead wires 81 and 82 and the signal line 83 are connected to the power connector 71. The communication line 84 is connected to the communication connector 72. The lead wires 81 and 82 are cables for transmitting power from or to the battery cell 31. The signal line 83 is a cable for transmitting signals output from various sensors. The communication line 84 is a cable for communication.

[0053] Lead wires 81 and 82 have a larger cross-sectional area than signal wire 83 and communication wire 84 in order to minimize losses due to resistance. Lead wires 81 and 82 have less flexibility than signal wire 83 and communication wire 84, and therefore exert a greater force (hereinafter referred to as "restoring force") that tries to restore them to their original shape when bent. This restoring force hinders the cable 8 when trying to fit it into a labyrinthine discharge passage.

[0054] A terminal block (not shown) is provided on the circuit board holder 61, and the terminals of a pair of positive and negative battery-side lead wires are fixed to the terminal block. The positive battery-side lead wire extends from a lead plate connected to the positive terminal of the parallel unit at the first end in the longitudinal direction X. The negative battery-side lead wire extends from a lead plate connected to the negative terminal of the parallel unit at the second end opposite to the first end. Lead wire 81 is connected to the positive battery-side lead wire at the terminal block and extends from the terminal block. Lead wire 82 is connected to the negative battery-side lead wire at the terminal block and extends from the terminal block. In this way, the battery block 3 is connected to the connector 7 (particularly the power connector 71) via the battery-side lead wires, the terminal block, and the lead wires 81 and 82.

[0055] The circuit board 62 is equipped with a monitoring module for monitoring the status of the battery cells 31 and a charge / discharge control module for controlling the charging and discharging of the battery cells 31. A board connector is also mounted on the circuit board 62. The signal line 83 and communication line 84 may be connected to the board connector.

[0056] Referring to Figures 3 and 4, all four cables 8 pass through one of the pair of discharge passages 40, the first discharge passage 40A. In other words, the discharge passage 40 includes the first discharge passage 40A, which is used for gas flow and cable routing, and the second discharge passage 40B, through which the cables 8 do not pass. In this embodiment, the first discharge passage 40A is located on one side in the width direction Y, and the second discharge passage 40B is located on the other side in the width direction Y, but the arrangement may be reversed.

[0057] Referring to Figures 5 to 7, the first duct member 4 comprises a duct base 41, a first side duct 42, a second side duct 43, and a duct cover 44 (see Figure 2). The first side duct 42 is located on one side in the width direction Y, and the second side duct 43 is located on the other side in the width direction Y. The duct base 41 and the first side duct 42 define the first discharge passage 40A. The duct base 41 and the second side duct 43 define the second discharge passage 40B.

[0058] The duct cover 44 (see Figure 2) is a flat plate extending in the width direction Y, and covers the first side duct 42 and the second side duct 43 from above. This closes the top of the pair of discharge passages 40. Figures 3 to 7 do not show the duct cover 44.

[0059] When assembling the first duct member 4, the first side duct 42 and the second side duct 43 are housed in the base 2A from above. The first side duct 42 is fastened to one side wall portion (first side wall 25) of the base 2A, and the second side duct 43 is fastened to the other side wall portion (second side wall 26). Rivets are used for fastening. After that, the duct base 41 is housed in the base 2A from above. This forms a pair of discharge passages 40, which are open to the top. In this state, the four cables 8 are housed in the first discharge passage 40A. Next, the duct cover 44 (see Figure 2) is attached, closing the tops of the pair of discharge passages 40. Finally, the cover 2B is assembled to the base 2A, and the first duct member 4 and the cables 8 are housed in the outer case 2.

[0060] Alternatively, the duct base 41 may be assembled to the base 2A first, and then the first side duct 42 and the second side duct 43 may be assembled to the base 2A. In this case as well, the wiring work will be carried out after these three components have been assembled to the base 2A.

[0061] The first side duct 42 has a bottom plate 42a, an outer plate 42b, a collision plate 42c, an inclined plate 42d, an inner plate 42e, and a partition plate 42f. Regarding the first side duct 42 and the first discharge passage 40A, one side in the width direction Y is the outside and the other side is the inside. Also, one side in the longitudinal direction X is the end wall side and the other side is the battery side. This also applies to the duct base 41 and the second side duct 43.

[0062] The bottom plate 42a is rectangular in plan view and is installed on the inner surface of the bottom wall 23. The pair of long edges of the bottom plate 42a are separated in the width direction Y and extend in the longitudinal direction X. The pair of short edges are separated in the longitudinal direction X and extend in the width direction Y.

[0063] The outer plate 42b is erected from the long edge on the outer side in the width direction Y of the bottom wall 23 and extends in the longitudinal direction X and the height direction Z. The outer plate 42b is superimposed on the inner surface of the first side wall 25 and fastened to the first side wall 25.

[0064] The impact plate 42c is erected from the short edge on the longitudinal X end wall side of the bottom wall 23 and extends in the width Y and height Z directions. The outer edge of the impact plate 42c in the width Y direction is continuous with the edge on the longitudinal X end wall side of the outer plate 42b, and these two edges form approximately a right angle.

[0065] The inclined plate 42d is inclined from the inner edge in the width direction Y of the impact plate 42c, and as it moves inward in the width direction Y, it moves toward the end wall in the longitudinal direction X. The inner plate 42e extends from the leading edge of the inclined plate 42d toward the battery in the longitudinal direction X. The base edge of the inclined plate 42d forms an obtuse angle with the inner edge in the width direction Y of the impact plate 42c, and the leading edge of the inclined plate 42d forms an obtuse angle with the end wall side edge of the inner plate 42e in the longitudinal direction X. The inclined plate 42d and the inner plate 42e are located inward in the width direction Y relative to the bottom plate 42a.

[0066] The partition plate 42f is erected from the long edge on the inner side in the width direction Y of the bottom plate 42a and extends in the width direction Y and the height direction Z. The partition plate 42f is parallel to the outer plate 42b and the inner plate 42e and is positioned between the outer plate 42b and the inner plate 42e.

[0067] The edge of the partition plate 42f on the longitudinal X end wall side faces the corner formed by the collision plate 42c and the inclined plate 42d, and is separated from the collision plate 42c and the inclined plate 42d with a small clearance in the longitudinal X battery direction.

[0068] The longitudinal edge of the inner plate 42e on the battery side terminates at the longitudinal end wall side relative to the longitudinal edge of the partition plate 42f on the battery side. On the other hand, the outer plate 42b extends longitudinally towards the battery side relative to the partition plate 42f and the bottom plate 42a.

[0069] The upper part of the extension extends in parallel with the inner plate 42e and the partition plate 42f. The lower part of the extension is bent at a right angle midway, forming the inflow plate 42g. The inflow plate 42g extends inward in the width direction Y from the outer plate 42b and is parallel to the collision plate 42c, and has a low-profile rectangular shape when viewed in the longitudinal direction X.

[0070] The lower edges of the outer plate 42b, collision plate 42c, inclined plate 42d, inner plate 42e, partition plate 42f, and inflow plate 42g are located at approximately the same position as each other. Furthermore, these lower edges are located at approximately the same position as the upper surface of the bottom plate 42a.

[0071] The upper edges of the outer plate 42b, collision plate 42c, inclined plate 42d, and inner plate 42e are at the same position relative to each other. The lower surface of the duct cover 44 (see Figure 2) is placed on these upper edges. The upper edge of the partition plate 42f is located below the upper edges of the outer plate 42b, etc., and the upper edge of the inlet plate 42g is located below the upper edge of the partition plate 42f.

[0072] The second side duct 43 has a structure that is symmetrical or mirror image of the first side duct 42. In the second side duct 43 and the second discharge passage 40B, the other side in the width direction Y is the outside and the other side is the inside. The second side duct 43, like the first side duct 42, has a bottom plate 43a, an outer plate 43b, a collision plate 43c, an inclined plate 43d, an inner plate 43e, a partition plate 43f, and an inflow plate 43g. The outer plate 43b is fastened to the second side wall 26.

[0073] Both the first side duct 42 and the second side duct 43 are manufactured by bending a single metal blank that has been formed into the required shape. Since the first side duct 42 and the second side duct 43 are mirror images of each other, the blank can be used interchangeably. When manufacturing the first side duct 42 and when manufacturing the second side duct 43, the blank can be bent with the front and back sides reversed. This reduces the manufacturing cost of the first duct member 4.

[0074] On the other hand, cable 8 passes through the first discharge passage 40A but not through the second discharge passage 40B. For the convenience of cable routing, it is preferable that the first discharge passage 40A is wider than the second discharge passage 40B. Even if the first discharge passage 40A is widened, the presence of cable 8 narrows the space that allows gas and sparks to pass through substantially, thus enabling gas cooling and spark extinguishing. Conversely, it is preferable that the second discharge passage 40B is narrower than the first discharge passage 40A in order to effectively achieve gas cooling and spark extinguishing by causing the gas to collide with the duct member. Thus, it is even preferable that the width of the flow paths differ between the first discharge passage 40A and the second discharge passage 40B, even while sharing the blank.

[0075] Therefore, in this embodiment, the end of the inner plate 42e on the battery side in the longitudinal direction X is folded back in a hairpin shape. As a result, the edge of the inner plate 42e on the battery side in the longitudinal direction X is positioned on the end wall side in the longitudinal direction X relative to the edge of the inner plate 43e on the battery side in the longitudinal direction X. As will be described later, the edges of the inner plates 42e and 43e on the battery side in the longitudinal direction X, together with the duct base 41, define the outlet 40b of the discharge passage 40, and the outlet 40b widens due to the offset of the edge toward the end wall side. By adding a hairpin-shaped bending process to the manufacturing of the first side duct 42, the outlet 40b of the first discharge passage 40A is widened while sharing the blank.

[0076] Furthermore, the upper end of the partition plate 42f is folded back in a hairpin shape. This positions the upper edge of the partition plate 42f lower than the upper edge of the partition plate 43f. As described later, the upper edge of the partition plate 42f, together with the duct cover 44, defines the overflow opening 40g of the discharge passage 40, and the offset of the upper edge downwards widens the overflow opening 40g. In this way, by adding a hairpin-shaped bend to the manufacturing of the first side duct 42, the first discharge passage 40A is widened while sharing the blank.

[0077] The duct base 41 includes a base plate 41a, a pair of notches 41b, a vertical wall 41c, a pair of protruding portions 41d, a first guide wall 41e, and a second guide wall 41f. In the duct base 41, the side closer to the center in the width direction Y is the inside, and the side further from the center is the outside.

[0078] The base plate 41a is superimposed on the inner surface of the bottom wall 23. The width of the base plate 41a is approximately equal to the distance between the inner surfaces of the first side wall 25 and the second side wall 26. The base plate 41a covers the inner surface of the bottom wall 23 over substantially the entire width Y direction of the bottom wall 23. A pair of notches 41b are provided on both edges of the base plate 41a in the width Y direction.

[0079] The base plate 41a has an edge that extends in the width direction Y on the end wall side in the longitudinal direction X. The vertical wall 41c is erected from this edge and extends in the width direction Y and the height direction Z. The lower end of the vertical wall 41c is provided with a pair of overhangs 41d that extend outwards on both sides in the width direction Y. The edges of the vertical wall 41c on both sides in the width direction Y extend upward from the upper base edge of the overhang 41d.

[0080] The first guide wall 41e extends from one end edge in the width direction Y of the vertical wall 41c towards the longitudinal end wall in the longitudinal direction X. The second guide wall 41f extends from the other end edge in the width direction Y of the vertical wall 41c towards the longitudinal end wall in the longitudinal direction X. The end edge of the first guide wall 41e on the longitudinal end wall side is positioned on the longitudinal end wall side of the second guide wall 41f on the longitudinal end wall side in the longitudinal direction X.

[0081] As described above, the duct base 41 is housed in the base 2A from above with the first side duct 42 and the second side duct 43 assembled to the base 2A. At this time, the inlet plates 42g and 43g pass through the pair of notches 41b, and the base plate 41a reaches the bottom wall 23. The edge of the base plate 41a on the longitudinal X end wall side is close to the edge of the bottom plates 42a and 43a on the longitudinal X battery side.

[0082] The pair of protruding portions 41d are close to the outer plates 42b and 43b, while the edges on both sides of the vertical wall 41c in the width direction Y are separated from the outer plates 42b and 43b by a clearance in the width direction Y. This clearance serves as an entrance 40a.

[0083] The end face of the vertical wall 41c on the longitudinal X end wall side abuts against the longitudinal X battery side edge of the partition plates 42f and 43f. On the other hand, the longitudinal X battery side edge of the inner plates 42e and 43e is separated from the longitudinal X end wall side edge of the vertical wall 41c with a clearance in the longitudinal X direction toward the longitudinal X end wall side. This clearance serves as an exit 40b.

[0084] The first guide wall 41e is positioned between the outer plate 42b and the partition plate 42f, parallel to both the outer plate 42b and the partition plate 42f. The edge of the first guide wall 41e on the longitudinal X end wall side is separated from the collision plate 42c with a clearance in the longitudinal X battery direction.

[0085] The second guide wall 41f is positioned between the outer plate 43b and the partition plate 43f, parallel to both the outer plate 43b and the partition plate 43f. The edge of the second guide wall 41f on the longitudinal X end wall side abuts against the longitudinal X battery side end face of the collision plate 43c.

[0086] The upper edges of the vertical wall 41c, the first guide wall 41e, and the second guide wall 41f are located in approximately the same position as the upper edges of the outer plates 42b and 43b, and abut against the inner surface of the duct cover 44 (see Figure 2). The lower edges of the first guide wall 41e and the second guide wall 41f are located in approximately the same position as the upper edge of the overhang portion 41d, and are situated between the upper surfaces of the bottom plates 42a and 43a and the upper edges of the partition plates 42f and 43f. The lower edge of the overhang portion 41d is located in approximately the same position as the upper surface of the base plate 41a, and also in approximately the same position as the upper surfaces of the bottom plates 42a and 43a and the lower edges of the outer plates 42b and 43b.

[0087] The first discharge passage 40A includes an inlet passage 40c, a central passage 40d, an outlet passage 40e, a submersible opening 40f, an overpass opening 40g, and a return passage 40h between the inlet 40a and the outlet 40b.

[0088] The inlet 40a is defined by the outer plate 42b, the upper edge of the overhang 41d, the edge of the vertical wall 41c on one side in the width direction Y (the edge of the first guide wall 41e on the battery side in the longitudinal direction X), and the duct cover 44 (see Figure 2). The outlet 40b is defined by the vertical wall 41c, the edge of the inner plate 42e on the battery side in the longitudinal direction X, and the duct cover 44 (see Figure 2).

[0089] The inlet passage 40c is defined by the bottom plate 42a, the outer plate 42b, the first guide wall 41e, and the duct cover 44 (see Figure 2). The inlet passage 40c extends from the inlet 40a towards the longitudinal X-end wall.

[0090] The central passage 40d is defined by the first guide wall 41e, the partition plate 42f, the vertical wall 41c, and the duct cover 44 (see Figure 2). The central passage 40d is adjacent to the inside of the inflow passage 40c in the width direction Y, via the first guide wall 41e, and extends generally in the longitudinal direction X.

[0091] The outflow passage 40e is defined by the first guide wall 41e, the inclined plate 42d, the inner plate 42e, the vertical wall 41c, and the duct cover 44 (see Figure 2). The outflow passage 40e is adjacent to the inside of the central passage 40d in the width direction Y, via the partition plate 42f, and extends generally in the longitudinal direction X. The end of the outflow passage 40e on the battery side in the longitudinal direction X connects to the outlet 40b.

[0092] The exit port 40f is defined by the bottom plate 42a and the lower edge of the first guide wall 41e. The lower part of the inlet passage 40c communicates with the lower part of the central passage 40d via the exit port 40f.

[0093] The overpass opening 40g is defined by the upper edge of the partition plate 42f and the duct cover 44 (see Figure 2). The upper part of the central passage 40d communicates with the upper part of the outflow passage 40e via the overpass opening 40g.

[0094] The return path 40h is defined by the longitudinal X-end wall side of the outer plate 42b, the collision plate 42c, the longitudinal X-end wall side of the first guide wall 41e, the longitudinal X-end wall side of the partition plate 42f, and the duct cover 44 (see Figure 2). The return path 40h connects the longitudinal X-end wall side of the inflow path 40c to the longitudinal X-end wall side of the central path 40d.

[0095] A portion of the gas in the first gap 2e flows into the inlet passage 40c of the first discharge passage 40A via the inlet 40a. An inlet plate 42g is positioned in front of the inlet 40a, allowing some of the gas and sparks to collide with the inlet plate 42g before entering the first discharge passage 40A.

[0096] A portion of the gas in the inlet passage 40c flows along the inlet passage 40c towards the longitudinal X end wall, collides with the collision plate 42c, reverses its flow direction in the return passage 40h, and flows into the central passage 40d from the longitudinal X end wall side. A portion of the gas in the inlet passage 40c flows downward and inward in the width direction Y, passes through the exit port 40f, and flows into the central passage 40d from below. Even if the gas in the central passage 40d flows in the longitudinal direction X, it will collide with the vertical wall or the collision plate. The gas in the central passage 40d flows upward and inward in the width direction Y, passes through the overpass port 40g, and flows into the outlet passage 40e from above. Even if the gas in the outlet passage 40e flows towards the longitudinal X end wall side, it will collide with the inclined plate 42d. The gas in the outflow passage 40e flows along the outflow passage 40e toward the battery in the longitudinal direction X, collides with the vertical wall 41c, changes direction by 90 degrees, and flows out into the first end space 2d via the outlet 40b.

[0097] In contrast, the second discharge passage 40B does not have a return passage 40h because the second guide wall 41f is in contact with the collision plate 43c. The inlet passage 40c is in communication with the central passage 40d only through the submerged exit 40f. Because the upper edge of the partition plate 43f is higher, the overpass 40g is narrower in the height direction Z compared to the first discharge passage 40A. Because the inner plate 43e is closer to the vertical wall 41c, the outlet 40b is narrower in the longitudinal direction X compared to the first discharge passage 40A. In at least these respects, the second discharge passage 40B is narrower than the first discharge passage 40A. Within the second discharge passage 40B, gas passes sequentially through the inlet passage 40c, the submerged exit 40f, the central passage 40d, the overpass 40g, and the outlet passage 40e between the inlet 40a and the outlet 40b.

[0098] The battery module 1 is provided on the first duct member 4 and further includes one or more protrusions 9 that project into the first discharge passage 40A.

[0099] In this embodiment, there are three projections 9, with a first projection 91, a second projection, and a third projection 93 protruding into the first discharge passage 40A through which the cable 8 passes. The projections 9 are expected to collide with gas and sparks, and are also expected to receive the restoring force of the cable 8. The first projection 91, the second projection 92, and the third projection 93 are arranged in this order with spacing along the direction of gas flow.

[0100] The first projection 91 is located at the upstream end of the three projections 9. The first projection 91 is provided on the inner surface of the outer plate 42b and protrudes from the connection between the inflow passage 40c and the return passage 40h, or from the upstream part of the return passage 40h. The first projection 91 protrudes inward in the width direction Y from the outer plate 42b. The first projection 91 is located closer to the longitudinal X end wall than the first guide wall 41e.

[0101] The second projection 92 is positioned in the middle of the three projections 9 in the flow direction. The second projection 92 is provided on the inner surface of the impact plate (the end face on the battery side in the longitudinal direction X) and protrudes into the return path 40h. The second projection 92 protrudes from the impact plate 42c toward the battery side in the longitudinal direction X. The second projection 92 is provided along the inner edge of the impact plate 42c in the width direction Y and is spaced apart from the first projection 91 in the width direction Y.

[0102] The third projection 93 is the downstream end projection of the three projections 9, located at the downstream end in the flow direction. The third projection 93 is provided on the vertical wall 41c and protrudes out to the outlet 40b of the first discharge passage 40A. The third projection 93 protrudes from the vertical wall 41c toward the longitudinal X end wall.

[0103] The first projection 91 and the second projection 92 are columnar in shape, elongated in the height direction Z. When the first side duct 42 is manufactured by bending a single metal plate, the first projection 91 and the second projection 92 are fixed to the first side duct 42 by welding or adhesive.

[0104] The third projection 93 is plate-shaped and has approximately the same thickness as the duct base 41. The duct base 41 can also be manufactured by bending a single metal plate. Therefore, the third projection 93 may also be integrally formed with the duct base 41 by bending the vertical wall 41c. In this case, the third projection 93 protrudes from the upper edge of the vertical wall 41c. The upper surface of the third projection 93 may be lower than the upper edge of the vertical wall 41c. In this case, the third projection 93 may be prepared separately from the duct base 41 and fixed to the duct base 41 by welding or adhesive.

[0105] The lower surface of projection 9 becomes higher as it moves downstream in the flow direction. In other words, the lower surface of the second projection 92 is higher than the lower surface of the first projection 91, and the lower surface of the third projection 93 is higher than the lower surface of the second projection 92.

[0106] The four cables 8 pass under the projection 9. The lead wires 81 and 82 are introduced from the inlet 40a into the first discharge passage 40A and pass through the inlet passage 40c, the return passage 40h, the overpass opening 40g, and the outflow passage 40e.

[0107] The lead wires 81 and 82 extend towards the longitudinal X-end wall at the lower part of the inflow passage 40c. The lead wires 81 and 82 pass below the first projection 91.

[0108] The lead wires 81 and 82 are directed upward in the return path 40h, and their extension direction is reversed to the longitudinal direction X. Since the first guide wall 41e is retracted toward the battery side in the longitudinal direction X and the upper edge of the partition plate 42f is retracted downward, even if the lead wires 81 and 82 are thick, they can be bent and placed in the first discharge path 40A. Within the return path 40h, the lead wires 81 and 82 pass below the second projection 92.

[0109] The lead wires 81 and 82 extend longitudinally towards the battery at the top of the outflow path 40e, are bent inward in the width direction Y, and pass through the outlet 40b. At the outlet 40b, the lead wires 81 and 82 pass below the third projection 93.

[0110] The signal line 83 and the communication line 84 are routed in the same way as the lead lines 81 and 82, passing under the three protrusions 9. The signal line 83 and the communication line 84 are thinner than the lead lines 81 and 82, and therefore can be bent with a larger curvature than the lead lines 81 and 82. Therefore, one or both of the signal line 83 and the communication line 84 may be led from the return path 40h through the central path 40d to the outflow path 40e.

[0111] Even if the cable 8 (especially the lead wires 81 and 82) tries to stand up due to its restoring force, that restoring force is absorbed by the underside of the projection 9. In other words, the cable 8 is locked in place by the projection 9. In particular, since the projection 9 (first projection 91, second projection 92) protrudes into the return path 40h where the curvature is large, the restoring of the cable 8 can be effectively suppressed.

[0112] Therefore, when the duct cover 44 is assembled to the first side duct 42 after the cable 8 has been placed in the first discharge passage 40A, it is possible to prevent the duct cover 44 from lifting up. Furthermore, when the cover 2B is subsequently assembled to the base 2A, it is possible to prevent the cover 2B from lifting up.

[0113] Furthermore, the presence of the protrusion 9 allows gas and sparks to collide with the protrusion 9. As a result, the temperature of the gas can be effectively reduced within the first discharge passage 40A, and sparks can be effectively extinguished.

[0114] 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.

[0115] The number of protrusions 9 is not particularly limited. The position of the upper surface of the protrusions 9 is not particularly limited. Protrusions 9 may also protrude into the discharge passage through which the cable 8 does not pass.

[0116] The projection 9 does not necessarily have to be provided on the duct member. The projection 9 only needs to protrude into the discharge passage, and may be provided, for example, on the outer casing 2.

[0117] The projection 9 may also be provided on the second duct member 5. The first duct member 4 and the second duct member 5 are point-symmetric with respect to the axis in the height direction Z. For this reason, the first side duct 42 of the first duct member 4 may be applied to the side duct on the other side in the width direction of the second duct member 5. In this case, the side duct with projection 9 can be shared between the first duct member 4 and the second duct member 5.

[0118] This disclosure may include the following embodiments: (Embodiment 1) A battery module comprising: an outer casing; a vent provided in the end wall of the outer casing; a battery block housed in the outer casing and holding a plurality of battery cells; a duct member housed in the outer casing and positioned between the battery block and the end wall, defining a labyrinthine discharge passage for guiding gas released from the battery cells; a connector attached to the end wall of the outer casing; a cable passing through the discharge passage and connecting the battery block to the connector; and one or more protrusions projecting into the discharge passage. (Embodiment 2) The battery module according to claim 1, wherein the cable passes below the protrusions. (Embodiment 3) The battery module according to embodiment 1 or 2, wherein the plurality of protrusions are spaced apart along the direction of gas flow. (Embodiment 4) The battery module according to embodiment 3, wherein the plurality of protrusions include a downstream end protrusion positioned at the downstream end in the direction of flow, and the downstream end protrusion projects into the outlet of the discharge passage. (Aspect 5) The battery module according to aspect 3 or 4, wherein the lower surfaces of the plurality of protrusions are raised as they are directed downstream in the flow direction. (Aspect 6) The battery module according to any one of aspects 1 to 5, wherein the discharge passage includes a return passage that reverses the flow direction of the gas, and at least one of the plurality of protrusions protrudes into the return passage.

[0119] 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 duct member 5 Second duct member 6 Circuit board block 7 Connector 8 Cable 9 Protrusion 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 32 Battery holder 33 Current collection structure 34 Cover plate 40, 50 Discharge passage 40A First discharge passage 40B Second discharge passage 40a Inlet 40b Outlet 40c Inflow path 40d Central path 40e Outflow path 40f Underpass 40g Overpass 40h Turnaround path 41 Duct base 41a Base plate 41c Vertical wall 41d Overhang 41e First guide wall 41f Second guide wall 42 First side duct 43 Second side duct 42a, 43a Bottom plate 42b, 43b Outer plate 42c, 43c Collision plate 42d, 43d Inclined plate 42e, 43e Inner plate 42f, 43f Partition plate 42g, 43g Inflow plate 44 Duct cover 61 Board holder 62 Circuit board 71 Power connector 72 Communication connector 81 Lead wire 82 Lead wire 83 Signal wire 84 Communication wire 91 First projection 92 Second projection 93 Third projection X Longitudinal direction Y Width direction Z Height direction

Claims

1. A battery module comprising: an outer casing; a ventilation opening provided in the end wall of the outer casing; a battery block housed in the outer casing and holding a plurality of battery cells; a duct member housed in the outer casing and positioned between the battery block and the end wall, defining a labyrinthine discharge passage for guiding gas released from the battery cells; a connector attached to the end wall of the outer casing; a cable passing through the discharge passage and connecting the battery block to the connector; and one or more protrusions projecting into the discharge passage.

2. The battery module according to claim 1, wherein the cable passes below the projection.

3. The battery module according to claim 1 or 2, wherein the plurality of protrusions are arranged at intervals along the direction of gas flow.

4. The battery module according to claim 3, wherein the plurality of protrusions include a downstream end protrusion located at the downstream end in the flow direction, and the downstream end protrusion protrudes out of the outlet of the discharge passage.

5. The battery module according to claim 3, wherein the lower surfaces of the plurality of protrusions are higher as they are directed downstream in the flow direction.

6. The battery module according to claim 1 or 2, wherein the discharge passage includes a return passage that reverses the direction of gas flow, and at least one of the plurality of protrusions protrudes into the return passage.

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