Battery module

Abstract

A battery module 1 comprises: a plurality of battery cells 10; first and second battery blocks 4A, 4B that are opposite of each other with a gap therebetween; and a passage member 70 that is interposed in this gap and defines exhaust passages 81. The plurality of battery cells 10 include opposing top cells 10T each having the top part 13 facing the gap, and opposing bottom cells 10B each having the bottom part 14 facing the gap. The opposing top cells 10T and the opposing bottom cells 10B are held in a state of being alternately aligned in a cell alignment direction. The passage member 70 has a plurality of partition parts 71 disposed between the opposing top cells 10T and the opposing bottom cells 10B in the cell alignment direction. The plurality of exhaust passages 81 are partitioned by the plurality of partition parts 71 and aligned in the cell alignment direction within the gap.

Description

Battery module

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

[0002] Patent Document 1 discloses a battery pack including two cell module assemblies housed in a pack case. The two cell module assemblies face each other with a predetermined safety distance therebetween. The safety distance is set so that when an abnormality occurs in the battery cells of one assembly, the abnormality can be prevented from spreading to the battery cells of the other assembly.

[0003] Japanese Patent Translation Publication No. 2024-522151

[0004] A space for securing a safety distance is required inside the pack case. Therefore, the battery pack becomes large as a whole.

[0005] An object of the present disclosure is to achieve both ensuring the safety and downsizing of the battery module.

[0006] One aspect of the present disclosure comprises a plurality of battery cells, a first battery block and a second battery block, each holding the plurality of battery cells and facing each other at a distance from each other, and a passage member interposed in the distance between the first battery block and the second battery block, defining an exhaust passage for guiding gas discharged from the battery cells into the distance, wherein each of the plurality of battery cells has an outer casing containing an electrolyte, a closing member for closing the outer casing, a top portion on which the closing member is provided, and a bottom portion opposite to the top portion, and in each of the first battery block and the second battery block, the plurality of battery cells have a top portion facing the distance The present invention provides a battery module comprising opposing cells and bottom-facing opposing cells with their bottoms facing the interval, wherein one or more top-facing cells and one or more bottom-facing cells are arranged alternately in the cell arrangement direction, the top-facing cells of one of the first battery block and the second battery block face the bottom-facing cells of the other of the first battery block and the second battery block across the interval, the passage member has a plurality of partitions arranged between the top-facing cells and the bottom-facing cells in the cell arrangement direction, and a plurality of exhaust passages are partitioned by the plurality of partitions and arranged in the cell arrangement direction within the interval.

[0007] According to this disclosure, it is possible to achieve both safety and miniaturization of the battery module.

[0008] A perspective view of the battery module according to the first embodiment. An exploded perspective view of the battery module of Figure 1. An exploded perspective view of the battery assembly of Figure 2. An exploded perspective view of the first battery block of Figure 3. An exploded perspective view of the second battery block of Figure 4. A plan view of the battery module of Figure 1, showing the upper case, circuit board unit, and first battery block removed. A longitudinal cross-sectional view of the battery module of Figure 1. An enlarged view of Figure 7. A cross-sectional view of the battery module of Figure 1, showing the exhaust passage facing the top opposing cell of the first battery block. A cross-sectional view of the battery module of Figure 1, showing the exhaust passage facing the top opposing cell of the second battery block. An exploded perspective view of the battery module according to the second embodiment. A partial longitudinal cross-sectional view of the battery module of Figure 11.

[0009] A battery module according to one embodiment of the present disclosure comprises a plurality of battery cells, a first battery block and a second battery block, each holding a plurality of battery cells and facing each other at a distance from each other, and a passage member interposed between the first battery block and the second battery block, defining an exhaust passage for guiding gas discharged from the battery cells into the gap, wherein each of the plurality of battery cells has an outer casing containing an electrolyte, a closing member for closing the outer casing, a top portion on which the closing member is provided, and a bottom portion opposite to the top portion, and in each of the first battery block and the second battery block, the plurality of battery cells are top-facing cells with their tops facing the gap and bottom-facing cells with their bottoms facing the gap. The battery includes one or more top-facing cells and one or more bottom-facing cells, which are arranged alternately in the cell arrangement direction, with one top-facing cell of the first battery block and the second battery block facing the other bottom-facing cell of the first battery block and the second battery block with a gap between them, and the passage member has a plurality of partitions arranged between the top-facing cells and the bottom-facing cells in the cell arrangement direction, and a plurality of exhaust passages are partitioned by the plurality of partitions and arranged in the cell arrangement direction with a gap between them, and each of the plurality of exhaust passages faces one top-facing cell of the first battery block and the second battery block and the other bottom-facing cell of the first battery block and the second battery block.

[0010] For the sake of explanation, of the pair of end faces of the battery cell, the side with the closing member is defined as the "top," and the opposite side is defined as the "bottom." If high-temperature gas is generated inside the battery cell, the gas may leak out of the battery cell from the outer casing through the closing member at the top due to its pressure.

[0011] According to the above configuration, the battery module is configured in which a first battery block and a second battery block are stacked with a gap between them. In both the first and second battery blocks, each battery cell is held in a position where its top or bottom faces the gap. Then, one or more (for example, two) top-facing cells and one or more (for example, two) bottom-facing cells are arranged alternately in the cell arrangement direction. The top-facing cells of the first battery block face the bottom-facing cells of the second battery block, and the bottom-facing cells of the first battery block face the top-facing cells of the second battery block across the gap. In the cell arrangement direction, the position where the top-facing cells and bottom-facing cells of the first battery block change is the same as the position where the top-facing cells and bottom-facing cells of the second battery block change.

[0012] In the arrangement of the battery cells as described above, a passage member having multiple partitions is interposed between the first battery block and the second battery block. The multiple partitions are positioned between top-facing cells and bottom-facing cells in the direction of cell arrangement. The passage member defines multiple exhaust passages separated by the multiple partitions.

[0013] Each exhaust passage faces the opposing cell at the top of one of the first and second battery blocks, and the opposing cell at the bottom of the other of the first and second battery blocks. Between the first and second battery blocks, a first exhaust passage facing the opposing cell at the top of the first battery block and a second exhaust passage facing the opposing cell at the top of the second battery block are arranged alternately in the direction of the cell arrangement. When gas is generated in the first battery block, the gas is guided to the first exhaust passage and discharged. When gas is generated in the second battery block, the gas is guided to the second exhaust passage and discharged.

[0014] Since the exhaust passages are defined by the passage members, safety can be easily ensured even when the first and second battery blocks are placed close together. The passage members partition the gap between the first and second battery blocks not in the direction of block stacking, but in the direction of cell arrangement. From this point of view, the gap between the first and second battery blocks can be reduced. In addition, the partition prevents the gas guided into each exhaust passage from reaching adjacent exhaust passages and the battery cells facing them. This prevents a situation where gas generated in one battery cell causes a chain reaction of gas generation in another battery cell. In this way, it is possible to achieve both the safety of the battery module and the miniaturization of the battery module.

[0015] In a battery module according to another embodiment of the present disclosure, the passage member has a plurality of connecting parts that sequentially connect a plurality of partition parts, and each of the connecting parts may be stacked on a bottom-facing cell.

[0016] According to the above configuration, a passage member having multiple partitions can be configured as a single member, reducing the number of components in the battery module. In addition, the bottom opposing cell is covered by the connection part. The connection part protects the bottom opposing cell from gas flowing into the exhaust passage.

[0017] In a battery module according to another embodiment of this disclosure, the passage member may be made of an insulating material.

[0018] With the above configuration, even if the electrolyte leaks out of the outer casing along with the gas, it is possible to prevent a short circuit between the battery cells of the first battery block and the battery cells of the second battery block via the electrolyte.

[0019] 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.

[0020] The battery module of this disclosure is applicable, for example, to emergency power sources such as battery backup units (BBUs) or to power the drive motors of electric vehicles. 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.

[0021] Referring to Figures 1 and 2, the battery module 1 according to the first embodiment comprises an outer case 2, a battery assembly 3, and a circuit board unit 6.

[0022] The outer casing 2 is made of an insulating material. For example, 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. For the sake of explanation, the direction in which the longer side of the rectangle extends will be called the "longitudinal direction X," and the direction in which the shorter side extends will be called the "width direction Y." The longitudinal direction X, the width direction Y, and the height direction Z are each perpendicular to the other two directions.

[0023] The outer casing 2 has a lower case 51 and an upper case 52 that can be divided in the height direction Z. The lower case 51 is a rectangular box shape that opens upward, and the upper case 52 is a rectangular box shape that opens downward. The opening edge of the lower case 51 and the opening edge of the upper case 52 are fastened together in a state where they are superimposed in the height direction Z. This defines the internal space of the outer casing 2. The battery assembly 3 and the circuit board unit 6 are housed in the internal space.

[0024] The outer casing 2 is provided with an exhaust port 2a for discharging high-temperature gases undesirably generated in the battery cell 10 (see Figures 4 and 5) from the outer casing 2. In the illustrated example, the exhaust port 2a is provided on the top wall 52a of the upper casing 52, but the position of the exhaust port 2a is not particularly limited.

[0025] The substrate unit 6 comprises a printed circuit board 61 and a substrate holder 62 that holds the printed circuit board 61. The printed circuit board 61 is made by welding electronic components (not shown) to a wiring board, which is made by wiring a board material that has been made by wiring an insulating board material. The substrate unit 6 is stacked on top of the battery assembly 3 and fastened to the battery assembly 3. The battery assembly 3, in particular its current collection structure 30, is connected to the wiring on the printed circuit board 61 via a plurality of harnesses 66. The harnesses 66 are routed in the space between the outer casing 2 and the battery assembly 3.

[0026] Referring to Figures 2 and 3, the battery assembly 3 comprises a plurality of battery blocks 4, spacers 5, and a passage member 70. The plurality of battery blocks 4 have similar configurations to each other. The plurality of battery blocks 4 are fixed to the spacers 5 and positioned with a gap between them. Hereinafter, when simply referred to as "gap," it refers to the gap between the battery blocks 4.

[0027] In this embodiment, two battery blocks 4 are positioned opposite each other with a gap in the height direction Z. The first battery block 4A is on the upper side, and the second battery block 4B is on the lower side.

[0028] Spacer 5 is a low-profile, elongated rectangular tube open on both sides in the height direction Z. Spacer 5 has a first side wall 41 and a second side wall 42 extending in the longitudinal direction X and facing each other in the width direction Y, and a first end wall 43 and a second end wall 44 extending in the width direction Y and facing each other in the longitudinal direction X. The first side wall 41 is on one side in the width direction Y (lower right side in Figure 3) relative to the second side wall 42. The first end wall 43 connects one end of the first side wall 41 to one end of the second side wall 42 on one side in the longitudinal direction X (lower left side in Figure 3). The second end wall 44 connects the other end of the first side wall 41 to the other end of the second side wall 42 on the other side in the longitudinal direction X (upper right side in Figure 3).

[0029] A pair of first bosses 45A are provided at the upper ends of the first end wall 43 and the second end wall 44, respectively, spaced apart in the width direction Y. The first battery block 4A is housed in the spacer 5 from above and fastened to the spacer 5 with bolts inserted through these first bosses 45A. Similarly, a pair of second bosses 45B are provided at the lower ends of the first end wall 43 and the second end wall 44, respectively, spaced apart in the width direction Y. The second battery block 4B is inserted into the spacer 5 from below and fastened to the spacer 5 with bolts inserted through these second bosses 45B.

[0030] The lower part of the first battery block 4A is housed in the upper part of the spacer 5, while its upper part protrudes upward from the spacer 5. The upper part of the second battery block 4B is housed in the lower part of the spacer 5, while its lower part protrudes downward from the spacer 5. The lower surface of the first battery block 4A and the upper surface of the second battery block 4B face each other within the spacer 5, separated by a gap in the height direction Z.

[0031] The passage member 70 is housed in the spacer 5 and interposed between the first battery block 4A and the second battery block 4B, defining an exhaust passage 81 (see Figures 6 to 10). The exhaust passage 81 guides the gas that has flowed out from the battery cell 10 (see Figures 4 and 5) into the space between the first battery block 4A and the second battery block 4B. The gas guided by the passage member 70 or the exhaust passage 81 is ultimately discharged outside the outer casing 2 through the exhaust port 2a. This point will be described later, but the configuration of the battery block 4 will be described first.

[0032] Referring to Figures 3 to 5, the battery block 4 has a plurality of battery cells 10, a cell holder 20 that holds the plurality of battery cells 10, and a current collection structure 30 that electrically connects the plurality of battery cells 10 held in the cell holder 20.

[0033] Referring to Figures 4 and 5, the battery cell 10 is a cylindrical lithium-ion secondary battery. However, the battery cell 10 may be a battery other than a cylindrical type, such as a prismatic battery, or a battery other than a lithium-ion secondary battery, such as an all-solid-state battery.

[0034] The battery cell 10 includes a bottomed cylindrical outer casing 11 that houses electrodes and electrolyte, and a closing member 12 that closes the opening of the outer casing 11. The outer casing 11 and the closing member 12 are made of a conductive material. The closing member 12 is attached to the outer casing 11 via an insulating material. The battery cell 10 has a pair of end faces that are spaced apart in the axial direction, and side faces that connect the end faces.

[0035] For the sake of explanation, the end face on the side where the closing member 12 is provided will be referred to as the "top 13," and the end face on the opposite side will be referred to as the "bottom 14." The top 13 is mainly composed of the closing member 12. The outer can 11 consists of the peripheral edge of the top 13, the bottom 14, and the side surfaces.

[0036] The outer can 11 and the closing member 12 have opposite polarities. For example, the closing member 12 (including the central part of the top 13) is the anode, and the outer can 11 (corresponding to the peripheral edge of the top 13 and the bottom 14) is the negative electrode. However, the polarities may be reversed.

[0037] Referring to Figures 3 to 5, the cell holder 20 has multiple cell housing sections 21 that individually house multiple battery cells 10. By housing the multiple battery cells 10 in the multiple cell housing sections 21, they are held in the cell holder 20 in a vertical orientation with their heights aligned. The vertical orientation is an orientation in which the axial direction (cell length direction) of the battery cells 10 is oriented in the height direction Z.

[0038] The cell housing section 21 defines a space having a shape complementary to the outer shape of the battery cell 10. In this embodiment, the cell housing section 21 is cylindrical and extends in the height direction Z.

[0039] The cell holder 20 has a pair of conductive plate mounting sections 22 on both sides in the height direction Z that close off the space defined by the cell housing section 21. Figures 3 to 5 are perspective views from above, and the conductive plate mounting section 22 on the upper side of the battery block 4 is explicitly shown.

[0040] In this embodiment, the cell holder 20 is composed of a first holder member 26 and a second holder member 27 that can be divided in the height direction Z. The first holder member 26 is housed in and fastened to the spacer 5. The second holder member 27 is located on the opposite side from the spacer 5 when viewed from the first holder member 26.

[0041] Since the first battery block 4A is positioned on top of the spacer 5, the first holder member 26 is on the lower side and the second holder member 27 is on the upper side. Conversely, since the second battery block 4B is positioned on bottom of the spacer 5, the first holder member 26 is on the upper side and the second holder member 27 is on the lower side. The first holder member 26 of the first battery block 4A and the first holder member 26 of the second battery block 4B face each other within the spacer 5.

[0042] The cell housing section 21 is composed of a first half 26a provided on the first holder member 26 and a second half 27a provided on the second holder member 27. The first half 26a and the second half 27a are bottomed cylindrical shapes. The first half 26a is open on the second holder member 27 side and closed on the spacer 5 side by the conductive plate installation section 22. The second half 27a is open on the first holder member 26 side and closed on the opposite side by the conductive plate installation section 22.

[0043] By assembling the first holder member 26 and the second holder member 27 together in the height direction Z, a pair of first halves 26a and second halves 27a are aligned with each other in the height direction Z, forming a single cell housing section 21. Half of the battery cell 10 is housed in the first half 26a, and the remainder is housed in the second half 27a.

[0044] Referring to FIGS. 4 and 5, in each battery block 4, a plurality of battery cells 10 form a plurality of cell rows 15 arranged in the longitudinal direction X. In each cell row 15, the plurality of battery cells 10 are arranged in the width direction Y. In the present embodiment, the longitudinal direction X corresponds to the direction in which the battery cells 10 or their cell rows 15 are arranged, that is, the "cell arrangement direction".

[0045] In each battery block 4, a plurality of battery cells 10 constitute a plurality of parallel units 16. Each parallel unit 16 consists of two or more battery cells 10 that form one row of cell row 15 or two or more adjacent cell rows 15. In each parallel unit 16, the two or more battery cells 10 are connected in parallel to each other. The plurality of parallel units 16 are sequentially connected in series.

[0046] As a mere example, in the present embodiment, the battery block 4 has 90 battery cells 10. That is, 90 battery cells 10 constitute 9 parallel units 16, and 10 battery cells 10 constitute one parallel unit 16. 90 battery cells 10 form 18 cell rows 15, and 5 battery cells 10 form one cell row 15. One parallel unit 16 is constituted by two adjacent cell rows 15, and 9 parallel units 16 are arranged in the longitudinal direction X.

[0047] Referring to FIG. 3, in the current collecting structure 30 according to the present embodiment, as a mere example, so-called both-side current collection, which is dispersedly arranged on both sides in the height direction Z when viewed from the cell holder 20, is adopted. Thereby, the electrical connection between the battery cells 10 as described above is realized.

[0048] Referring to FIGS. 4 and 5, two or more battery cells 10 that constitute the same one parallel unit 16 are all held by the cell holder 20 in a posture with their tops 13 facing the same side. A parallel unit 16 composed only of battery cells 10 with their tops 13 facing upward and a parallel unit 16 composed only of battery cells 10 with their tops 13 facing downward are alternately arranged in the longitudinal direction X.

[0049] Each of the pair of conductive plate mounting sections 22 has multiple openings that partially expose the end faces of each of the multiple battery cells 10. The current collection structure 30 has a first current collection section 31 installed in the conductive plate mounting section 22 on the spacer 5 side, and a second current collection section 36 installed in the conductive plate mounting section 22 on the opposite side. Both the first current collection section 31 and the second current collection section 36 have multiple conductive plates 32, 37 stacked on the conductive plate mounting section 22 and arranged in the longitudinal direction X, and insulating plates 33, 38 stacked on the side opposite to the cell holder 20 when viewed from the conductive plates 32, 37. Each conductive plate 32, 37 is mechanically and electrically connected to the electrodes of the battery cells 10 of one or two parallel units 16 through the openings in the conductive plate mounting section 22. This realizes parallel connection within the parallel unit 16 and series connection between the parallel units 16.

[0050] For the sake of explanation, a battery cell 10 with its top 13 facing the space will be referred to as a "top-facing cell 10T," and a battery cell 10 with its bottom 14 facing the space will be referred to as a "bottom-facing cell 10B." Since all battery cells 10 are in a vertical orientation, the battery cells 10 that make up the battery assembly 3 are either top-facing cells 10T or bottom-facing cells 10B.

[0051] In the first battery block 4A, the battery cell 10 with its top 13 facing upwards is the bottom-facing cell 10B, and the battery cell 10 with its top 13 facing downwards is the top-facing cell 10T. Conversely, in the second battery block 4B, the battery cell 10 with its top 13 facing upwards is the top-facing cell 10T, and the battery cell 10 with its top 13 facing downwards is the bottom-facing cell 10B.

[0052] The number of parallel units 16 and the number of battery cells 10 constituting each parallel unit 16 are the same across the multiple battery blocks 4. The multiple battery cells 10 constituting the first battery block 4A are opposite each of the multiple battery cells 10 constituting the second battery block 4B in the height direction Z, with a gap in between.

[0053] Referring to Figures 4, 5, and 7, the top opposing cell 10T of the first battery block 4A faces the bottom opposing cell 10B of the second battery block 4B, separated by a gap. The bottom opposing cell 10B of the first battery block 4A faces the top opposing cell 10T of the second battery block 4B, separated by a gap.

[0054] Referring to Figures 4 and 7, in the first battery block 4A, the odd-numbered parallel units 16, counting from one side in the longitudinal direction X (the lower left side in Figure 4), are composed of top-facing cells 10T, and the even-numbered parallel units 16 are composed of bottom-facing cells 10B.

[0055] Referring to Figures 5 and 7, conversely, in the second battery block 4B, the odd-numbered parallel units 16, counting from one side in the longitudinal direction X (the lower left side in Figure 5), are composed of bottom-facing cells 10B, and the even-numbered parallel units 16 are composed of top-facing cells 10T.

[0056] Therefore, in each battery block 4, one or more top-facing cells 10T and one or more bottom-facing cells 10B are arranged alternately in the longitudinal direction X. Here, "one or more" may correspond to the number of rows of cell columns 15 that constitute one parallel unit 16. In this embodiment, the number of rows is two, and two top-facing cells 10T and two bottom-facing cells 10B are arranged alternately. In the first battery block 4A, top-facing cells 10T are arranged at one end in the longitudinal direction X and next to it. Conversely, in the second battery block 4B, bottom-facing cells 10B are arranged at one end in the longitudinal direction X and next to it.

[0057] Referring to Figures 3, 6, and 7, the passage member 70 according to this embodiment is made of a material having insulating and flame-retardant properties, such as melamine resin, and is a single unit. The passage member 70 has a plurality of partition sections 71 and a plurality of connecting sections 72 that sequentially connect the plurality of partition sections 71.

[0058] Multiple partitions 71 are arranged at intervals in the longitudinal direction X. Each partition 71 is plate-shaped with its thickness direction aligned with the longitudinal direction X, and extends in the width direction Y and height direction Z. The height of each partition 71 corresponds to the distance between the first battery block 4A and the second battery block 4B.

[0059] Each connecting portion 72 is a horizontal flat plate with its thickness direction oriented in the height direction Z, and is elongated in the width direction Y and short in the longitudinal direction X. The connecting portion 72 includes a first connecting portion 72A that connects the lower ends of two adjacent partition portions 71 and a second connecting portion 72B that connects the upper ends of two adjacent partition portions 71. The first connecting portion 72A and the second connecting portion 72B are arranged alternately in the longitudinal direction X.

[0060] Therefore, as shown in Figure 7, when viewed from the width direction Y, the multiple partitions 71 and the multiple connecting parts 72 have a rectangular wave shape and extend in a zigzag pattern upward or downward from one side to the other in the longitudinal direction X.

[0061] The passage member 70 has a projection 73a that protrudes from the partition portion 71 at one end in the longitudinal direction X to the other side in the longitudinal direction X. The passage member 70 has a projection 73b that protrudes from the partition portion 71 at the other end in the longitudinal direction X to the other side in the longitudinal direction X.

[0062] Referring to Figures 6 and 7, the partition 71 is positioned between the top opposing cell 10T and the bottom opposing cell 10B in the longitudinal direction X.

[0063] In this regard, in each battery block 4, one or more (for example, two) top-facing cells 10T and one or more (for example, two) bottom-facing cells 10B are arranged alternately in the longitudinal direction X. The partition portion 71 is located in the portion between the top-facing cells 10T and the bottom-facing cells 10B. In other words, the partition portion 71 is located in the portion where the region switches from where the top-facing cells 10T are located to where the bottom-facing cells 10B are located, or vice versa, from one side to the other in the longitudinal direction X. In yet another way, the partition portion 71 is located at the boundary portion between two adjacent parallel units 16.

[0064] Whether it is the portion between the top opposing cell 10T and the bottom opposing cell 10B, the switching portion between the arrangement area of ​​the top opposing cell 10T and the arrangement area of ​​the bottom opposing cell 10B, or the boundary portion of the parallel unit 16, such portions are located in the same position in the longitudinal direction X for both the first battery block 4A and the second battery block 4B.

[0065] The number of partition sections 71 corresponds to the number of such sections, that is, it is one less than the number of parallel units 16. The number of connecting sections 72 is one less than the number of partition sections 71. The sum of the number of connecting sections 72 and the number of protruding sections 73a and 73b (two of them) corresponds to the number of parallel units 16. When there are nine parallel units 16, the passage member 70 has eight partition sections 71 and seven connecting sections 72, and the pair of protruding sections 73a and 73b and the seven connecting sections 72 sandwiched between them correspond to nine parallel units 16.

[0066] As a result, the gap between the first battery block 4A and the second battery block 4B is divided into multiple exhaust passages 81 by multiple partitions 71. The multiple exhaust passages 81 are arranged in the longitudinal direction X. Each exhaust passage 81 is relatively long in the width direction Y. The number of exhaust passages 81 is one greater than the number of partitions 71, that is, it corresponds to the number of parallel units 16.

[0067] The multiple exhaust passages 81 include a first exhaust passage 81A (see Figure 9) that faces the top opposing cell 10T of the first battery block 4A and the bottom opposing cell 10B of the second battery block 4B, and a second exhaust passage 81B (see Figure 10) that faces the bottom opposing cell 10B of the first battery block 4A and the top opposing cell 10T of the second battery block 4B. Within the gap, one first exhaust passage 81A and one second exhaust passage 81B are arranged alternately in the longitudinal direction X.

[0068] Referring to Figures 8 and 9, the first connection portion 72A is placed on top of the upper surface of the second battery block 4B. The first connection portion 72A covers the bottom opposing cell 10B of the second battery block 4B. Together with the two partition portions 73 connected by itself, the first connection portion 72A defines the first exhaust passage 81A.

[0069] Referring to Figures 8 and 10, the second connection portion 72B is superimposed on the lower surface of the first battery block 4A from below. The second connection portion 72B covers the bottom opposing cell 10B of the first battery block 4A. Together with the two partition portions 73 connected by itself, the second connection portion 72B defines the second exhaust passage 81B.

[0070] In this embodiment, at one end in the longitudinal direction X, the parallel unit 16 of the first battery block 4A is composed of top-facing cells 10T, and the parallel unit 16 of the second battery block 4B is composed of bottom-facing cells 10B. The protruding portion 73a corresponds to the parallel unit 16 at the end and, like the connecting portion 72, covers the bottom-facing cells 10B. That is, the protruding portion 73a protrudes from the lower end of the partition portion 71 and is superimposed on the second battery block 4B. The protruding portion 73a, together with the partition portion 71 continuous with the protruding portion 73a, defines the first exhaust passage 81A.

[0071] The protruding portion 73b corresponds to the parallel unit 16 at the other end in the longitudinal direction X. The protruding portion 73b protrudes from the lower end of the partition portion 71, overlaps with the second battery block 4B, and covers the bottom opposing cell 10B of the second battery block 4B. Together with the partition portion 71 which is continuous with the protruding portion 73b, the protruding portion 73b defines the first exhaust passage 81A.

[0072] Referring to Figure 3, the spacer 5 has a first side slit 46a provided in the first side wall 41 and a second side slit 46b provided in the second side wall 42. The first side slit 46a and the second side slit 46b connect the exhaust passage 81 to the space outside the battery assembly 3. The first side slit 46a extends in the longitudinal direction X from the center of the height direction Z of the first side wall 41. The relationship between the second side slit 46b and the second side wall 42 is similar.

[0073] Referring to Figures 7 to 10, a gas passage 80 is provided inside the outer casing 2 to guide the gas generated by the battery cell 10. The exhaust passage 81 described above constitutes a part of the gas passage 80. The gas passage 80 includes a vertical passage 82 defined by the side surface of the battery assembly 3 and the inner surface of the side wall of the outer casing 2, extending in the height direction Z. The gas passage 80 also includes a downstream passage 83 defined by the top surface of the substrate unit 6 and the inner surface of the top wall 52a of the upper casing 52, extending horizontally. The exhaust passage 81 communicates with the vertical passage 82 via the first side slit 46a and the second side slit 46b. The upper part of the vertical passage 82 communicates with the downstream passage 83. The exhaust port 2a is open to the downstream passage 83.

[0074] During operation of the battery module 1 described above, due to some abnormality, the inside of a certain battery cell 10 may become extremely hot. When the internal pressure of the battery cell 10 rises, the closing member 12 that constitutes the top portion 13 detaches from the outer casing 11, or the cell safety valve (details not shown) provided on the closing member 12 opens. As a result, high-temperature and high-pressure gas is discharged from the outer casing 11 through the top portion 13 to the outside of the battery cell 10.

[0075] The top portion 13 of the top opposing cell 10T is covered by the first current collector 31. The insulating plate 33 of the first current collector 31 is provided with multiple current collector safety valves 34 at positions opposite to the top opposing cell 10T in the height direction Z. The top portion 13 of the bottom opposing cell 10B is covered by the second current collector 36. The insulating plate 38 of the second current collector 36 is also provided with multiple current collector safety valves (not shown) at positions opposite to the bottom opposing cell 10B in the height direction Z.

[0076] When gas is generated in the top opposing cell 10T of the first battery block 4A, the current collector safety valve 34 opens due to the gas pressure, and the gas flows into the first exhaust passage 81A. The gas is guided by the first exhaust passage 81A to flow in the width direction Y and flows out through the first side slit 46a and / or the second side slit 46b into the longitudinal passage 82, i.e., outside the battery assembly 3.

[0077] The gas is prevented from flowing in the longitudinal direction X by the partition portion 71 that defines the first exhaust passage 81A. Therefore, it is possible to prevent an abnormality in one battery cell 10 from spreading to another battery cell 10 located in the longitudinal direction X via the high-temperature gas. Since the passage member 70 is flame-retardant, even if the partition portion 71 is exposed to the high-temperature gas, it is possible to prevent the partition portion 71 from melting, and thus effectively prevent the propagation of abnormalities.

[0078] If a malfunction occurs in the battery cell 10, the electrolyte may be scattered outside the battery cell 10 along with the gas. Since the passage member 70 is insulating, even if the electrolyte adheres to the partition portion 71, it is possible to prevent unwanted short circuits from occurring between the battery cells 10.

[0079] The first exhaust passage 81A is open to the top opposing cell 10T of the first battery block 4A, while the bottom opposing cell 10B of the second battery block 4B, which is opposite to it in the height direction Z, is covered by the first connection part 72A. Since the first connection part 72A is flame-retardant and insulating, it can prevent abnormalities from occurring in the bottom opposing cell 10B due to gas flowing into the first exhaust passage 81A, and can also prevent unwanted short circuits from occurring between the opposing battery cells 10 due to electrolyte scattered in the first exhaust passage 81A.

[0080] The same applies when gas is generated in the top opposing cell 10T of the second battery block 4B. The current collection safety valve 34 opens due to the gas pressure, and the gas flows into the second exhaust passage 81B. This prevents the gas from flowing in the longitudinal direction X, thus preventing unwanted short circuits caused by the electrolyte.

[0081] As described above, since the exhaust passage 81 is defined by the passage member 70, safety can be easily ensured even when the first battery block 4A and the second battery block 4B are placed close to each other. The passage member 70 partitions the gap between the first battery block 4A and the second battery block 4B not in the block stacking direction (height direction Z), but in the cell arrangement direction (longitudinal direction X). From this point of view as well, the gap between the first battery block 4A and the second battery block 4B can be reduced. This makes it possible to achieve both ensuring the safety of the battery module 1 and miniaturizing the battery module 1.

[0082] The passage member 70 comprises multiple partition sections 71, which are sequentially connected via connecting sections 72. As a result, as described above, the propagation of abnormalities and unwanted short circuits between battery cells 10 facing each other in the height direction Z can be effectively prevented. Furthermore, since the passage member 70 is a single component, it contributes to reducing the number of parts in the battery assembly 3.

[0083] Next, referring to Figures 11 and 12, the battery module 1 according to the second embodiment will be described, focusing on the differences from the first embodiment.

[0084] In this embodiment, the connecting portion 72 (see Figure 3) is omitted from the passage member 70. Multiple partition portions 71 are composed of multiple separate passage members 70 that are independent of each other. In this case as well, the gap is divided into multiple exhaust passages 81 by the multiple partition portions 71. Therefore, as in the first embodiment, it is possible to prevent gas from flowing in the longitudinal direction X, thereby ensuring the safety of the battery module 1 and achieving miniaturization of the battery module 1.

[0085] While embodiments have been described above, the above configuration can be modified as appropriate within the scope of the spirit of this disclosure.

[0086] The number of battery blocks may be three or more. Multiple battery blocks may be arranged along directions other than the height direction Z.

[0087] The arrangement method of the battery cells 10 is not particularly limited. Depending on the arrangement of the battery cells 10 or the number of battery cells 10 constituting the parallel unit 16 or the number of rows in the cell row 15, the position and number of partitions can also be changed as appropriate.

[0088] (Embodiment 1) A plurality of battery cells, a first battery block and a second battery block, each holding the plurality of battery cells and facing each other with a gap between them, and a passage member interposed in the gap between the first battery block and the second battery block, defining an exhaust passage for guiding gas discharged from the battery cells to the gap, wherein each of the plurality of battery cells has an outer container containing an electrolyte, a closing member for closing the outer container, a top portion on which the closing member is provided, and a bottom portion opposite to the top portion, and in each of the first battery block and the second battery block, the plurality of battery cells include top-facing cells with their tops facing the gap and bottom-facing cells with their bottoms facing the gap, and one or more of the top-facing cells and one or more of the bottom-facing cells are arranged alternately in the cell arrangement direction, and the top-facing cells of one of the first battery block and the second battery block face the bottom-facing cells of the other of the first battery block and the second battery block across the gap, (Aspect 2) The battery module, wherein the passage member comprises a plurality of partitions arranged between the top-facing cells and the bottom-facing cells in the cell arrangement direction, and the plurality of exhaust passages are partitioned by the plurality of partitions and arranged in the cell arrangement direction within the interval, and each of the plurality of exhaust passages faces the top-facing cell of one of the first battery block and the second battery block and the bottom-facing cell of the other of the first battery block and the second battery block. (Aspect 3) The battery module, wherein the passage member comprises a plurality of connecting parts that sequentially connect the plurality of partitions, and each of the connecting parts is stacked on the bottom-facing cells.

[0089] 1 Battery module 2 Outer casing 2a Exhaust port 3 Battery assembly 4 Battery block 4A First battery block 4B Second battery block 5 Spacer 6 Circuit board unit 10 Battery cell 10T Top opposing cell 10B Bottom opposing cell 11 Outer casing 12 Closure member 13 Top 14 Bottom 15 Cell row 16 Parallel unit 20 Cell holder 21 Cell housing section 22 Conductive plate installation section 26 First holder member 26a First half 27 Second holder member 27a Second half 30 Current collection structure 31 First current collection section 36 Second current collection section 32, 37 Conductive plate 33, 38 Insulating plate 34 Current collection safety valve 41 First side wall 42 Second side wall 43 First end wall 44 Second end wall 45A 1st boss 45B 2nd boss 46a 1st side slit 46b 2nd side slit 51 Lower case 52 Upper case 52a Top wall 61 Printed circuit board 62 Board holder 66 Harness 70 Passage member 71 Partition 72 Connection part 72A 1st connection part 72B 2nd connection parts 73a, 73b Protruding part 80 Gas passage 81 Exhaust passage 81A 1st exhaust passage 81B 2nd exhaust passage 82 Vertical passage 83 Downstream passage X Longitudinal direction Y Width direction Z Height direction

Claims

1. A plurality of battery cells, a first battery block and a second battery block, each holding the plurality of battery cells and facing each other with a gap between them, and a passage member interposed in the gap between the first battery block and the second battery block, defining an exhaust passage for guiding gas discharged from the battery cells to the gap, wherein each of the plurality of battery cells has an outer container containing an electrolyte, a closing member for closing the outer container, a top portion on which the closing member is provided, and a bottom portion opposite to the top portion, and in each of the first battery block and the second battery block, the plurality of battery cells include top-facing cells with their tops facing the gap and bottom-facing cells with their bottoms facing the gap, and one or more of the top-facing cells and one or more of the bottom-facing cells are arranged alternately in the cell arrangement direction, and the top-facing cells of one of the first battery block and the second battery block face the bottom-facing cells of the other of the first battery block and the second battery block across the gap, The passage member constitutes a plurality of partitions arranged between the top-facing cells and the bottom-facing cells in the cell arrangement direction, the plurality of exhaust passages are partitioned by the plurality of partitions and arranged in the cell arrangement direction within the interval, and each of the plurality of exhaust passages faces the top-facing cell of one of the first battery block and the second battery block and the bottom-facing cell of the other of the first battery block and the second battery block, respectively, in a battery module.

2. The battery module according to claim 1, wherein the passage member has a plurality of connecting parts that sequentially connect the plurality of partition parts, and each of the connecting parts is stacked on the bottom opposing cell.

3. The battery module according to claim 1 or 2, wherein the passage member is made of an insulating material.

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