Battery module

Abstract

This allows for a balance between improving gas emission efficiency and enhancing the safety of battery modules. [Solution] The battery module 100 comprises a plurality of battery cells 5, a cell holder 6 including a housing space 62 for housing the plurality of battery cells 5, and a cover 8 positioned to overlap the cell holder 6 when viewed along a first direction. The cover 8 includes a plurality of restricting portions 82 that restrict the flow direction of gas discharged from the battery cells 5, and the restricting portions 82 guide the gas toward the center of the cover 8 in a second direction perpendicular to the first direction.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a battery module including a module case that houses battery cells. In order to discharge vent gas generated from a thermally runaway battery cell to the outside of the module case, a plurality of vent holes are provided in one surface of the module case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Simply providing a plurality of vent holes may easily release flames from a thermally runaway battery cell to the outside of the module case and may also make it difficult to control the discharge direction of the vent gas. Therefore, there is a risk of expanding damage to the module case and its surroundings.

[0005] An object of the present invention is to achieve both an improvement in gas discharge efficiency and an improvement in the safety of the battery module.

Means for Solving the Problems

[0006] One aspect of the present invention provides a battery module comprising a plurality of battery cells, a cell holder including a housing space for housing the plurality of battery cells, and a cover disposed so as to overlap the cell holder when viewed along a first direction, wherein the cover includes a plurality of restricting portions that restrict the flow direction of gas discharged from the battery cells, and the restricting portions guide the gas toward the central portion of the cover in a second direction perpendicular to the first direction. [Effects of the Invention]

[0007] According to the present invention, it is possible to achieve both improved gas discharge efficiency and improved safety of the battery module. [Brief explanation of the drawing]

[0008] [Figure 1] A perspective view of a battery module according to an embodiment. [Figure 2] Figure 1 shows an exploded perspective view of the battery module. [Figure 3] A cross-sectional view of the battery module along line III-III shown in Figure 1. [Figure 4] A perspective view of the battery assembly shown in Figure 2. [Figure 5] Figure 4 shows an exploded perspective view of the battery assembly. [Figure 6] Figure 5 shows a perspective view of the battery cell. [Figure 7] Figure 3 shows a magnified view of the battery cell and its vicinity. [Figure 8A] A cross-sectional view of a battery module obtained by cutting the regulatory portion according to the embodiment along the X direction. [Figure 8B] Figure 8A shows an enlarged view of the regulated area and its vicinity. [Figure 9] Figure 4 shows an exploded perspective view of the battery assembly with the cover removed. [Figure 10A] A perspective view of the cover shown in Figure 4. [Figure 10B] Figure 10A shows an enlarged view of the regulated area and its vicinity. [Figure 11A] Figure 5 shows a plan view of the heat conductive member and cover. [Figure 11B] An enlarged view of the restricting portion shown in FIG. 11A and its vicinity. [Figure 12] A cross-sectional view showing the gas flow according to the embodiment.

Best Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same or corresponding elements are denoted by the same reference numerals throughout, and redundant detailed descriptions are omitted.

[0010] A battery module according to an embodiment of the present disclosure includes a plurality of battery cells, a cell holder including an accommodation space for accommodating the plurality of battery cells, and a cover arranged to overlap the cell holder when viewed along a first direction. The cover includes a plurality of restricting portions for restricting the flow direction of the gas discharged from the battery cells, and the restricting portions guide the gas toward the central portion of the cover in a second direction orthogonal to the first direction.

[0011] According to the above configuration, since the restricting portions guide the gas toward the central portion of the cover in the second direction, the gases discharged from the restricting portions facing each other across the central portion collide with each other, and the flow velocity of the gas can be reduced. As a result, a long residence time of the gas inside the battery module can be ensured. Thereby, the temperature of the gas at the time of being discharged to the outside of the battery module can be reduced, and the safety of the battery module can be improved. Further, since there are a plurality of restricting portions, the gas discharge efficiency is also improved. That is, according to the above configuration, it is possible to achieve both an improvement in the gas discharge efficiency and an improvement in the safety of the battery module.

[0012] In a battery module according to another embodiment of the present disclosure, the plurality of restricting portions may be arranged at intervals in the second direction.

[0013] According to the above configuration, since the plurality of regulating parts are arranged at intervals, the gas can be discharged in a dispersed manner. Thereby, the discharge efficiency of the gas is improved. Further, since the gas is dispersed, the gas can be efficiently cooled, and the safety of the battery module can be improved.

[0014] In the battery module according to another embodiment of the present disclosure, the interval between adjacent regulating parts may be narrower on the side closer to the central part of the cover in the second direction.

[0015] According to the above configuration, since the interval at the central part where the gas is likely to accumulate is narrow, a decrease in the discharge efficiency of the gas can be suppressed. Thereby, the temperature of the gas can also be decreased, and the safety of the battery module can be improved.

[0016] In the battery module according to another embodiment of the present disclosure, the plurality of regulating parts may be arranged linearly along the second direction.

[0017] According to the above configuration, since the plurality of regulating parts are arranged linearly, the gas can be discharged uniformly without bias. Further, since the gas can be discharged uniformly, the gas can be efficiently cooled, and the safety of the battery module can be improved.

[0018] In the battery module according to another embodiment of the present disclosure, the plurality of regulating parts may be arranged at the central part in the third direction orthogonal to the first direction and the second direction.

[0019] According to the above configuration, since the plurality of regulating parts are arranged at the central part in the third direction, the gas can be discharged uniformly without bias. Further, since the gas can be discharged uniformly, the gas can be efficiently cooled, and the safety of the battery module can be improved.

[0020] A battery module according to another embodiment of the present disclosure further comprises a case housing a plurality of the battery cells, the cell holders, and the cover, the case including a first vent formed at one end in the second direction through which the gas can pass, and a second vent formed at the other end in the second direction through which the gas can pass, the regulating portion including a communication opening communicating with the housing space, and a guide wall portion disposed to cover at least a portion of the communication opening and defining an opening for releasing the gas from the communication opening, the guide wall portion may define the opening so as to face the distal vent on the farther side of the first vent and the second vent.

[0021] According to the above configuration, the opening is defined to face the distal vent, which is the farther of the two vents (the first and second vents). This increases the distance the gas travels to reach either the first or second vent. In other words, it allows for a longer residence time of the gas inside the case, and reduces the pressure and temperature of the gas when it is discharged outside the case. As a result, the safety of the battery module and its surroundings can be improved.

[0022] A battery module according to another embodiment of the present disclosure further comprises a case housing a plurality of the battery cells, the cell holders, and the cover, the case including a first vent formed at one end in the second direction through which the gas can pass, and a second vent formed at the other end in the second direction through which the gas can pass, the regulating portion including a communication opening communicating with the housing space, and a guide wall portion disposed to cover at least a portion of the communication opening and defining an opening for releasing the gas from the communication opening, the guide wall portion may include a regulating wall disposed on the side of the proximal vent that is closer to the first vent and the second vent.

[0023] According to the above configuration, the guide wall includes a regulating wall positioned on the side of the proximal vent, which is the closer of the first and second vents. In other words, the gas flows toward the distal vent, not the proximal vent. This allows the distance the gas travels to reach either the first or second vent to be increased. This means that the residence time of the gas inside the case can be increased, and the pressure and temperature of the gas at the time it is discharged outside the case can be reduced. As a result, the safety of the battery module and its surroundings can be improved.

[0024] A battery module according to another embodiment of the present disclosure further comprises a thermal conductive member disposed between the cell holder and the cover, the thermal conductive member including a sheet-like base, and the restricting portion may be positioned to overlap with a through-hole penetrating the base when viewed along the first direction.

[0025] According to the above configuration, it is possible to avoid obstruction of gas discharge by the heat conductive member and improve gas discharge efficiency.

[0026] The embodiments of this disclosure will be described below with reference to the drawings. Terms indicating direction and position, such as "up" and "down," used in the description are for the purpose of facilitating understanding of the drawings and do not limit the technical scope of this disclosure. Throughout the drawings, the same or equivalent components are denoted by the same reference numerals. The following embodiments are merely examples of this disclosure, and the dimensions, materials, shapes, arrangements, etc., are illustrative. Note that the size and positional relationships in the illustrations may be exaggerated to clarify the explanation.

[0027] Referring to Figures 1 to 3, the battery module 100 according to this embodiment comprises a case 1, a fan 2, a voltage conversion circuit 3, and a battery assembly 4. The fan 2, the voltage conversion circuit 3, and the battery assembly 4 are housed in the case 1.

[0028] Case 1 is a rectangular parallelepiped outer casing and consists of a first case member 11, a second case member 12, a first end plate 13, and a second end plate 14. However, the divided parts that make up Case 1 can be changed as appropriate.

[0029] The first case member 11 is flat and includes a first base wall 1a. The second case member 12 includes a flat second base wall 1b. The first base wall 1a and the second base wall 1b face each other.

[0030] Hereinafter, the direction in which the first base wall 1a and the second base wall 1b face each other will be referred to as the Z direction (an example of the first direction), the direction perpendicular to the Z direction that aligns with the longitudinal direction of Case 1 will be referred to as the X direction (an example of the second direction), and the direction perpendicular to both the X and Z directions will be referred to as the Y direction (an example of the third direction). In this embodiment, the Z direction is the direction aligned with the vertical direction, with one side of the Z direction (+Z side) being referred to as the upper side and the other side (-Z side) as the lower side. Also, one side of the X direction (+X side) will be referred to as the front side and the other side of the X direction (-X side) as the rear side.

[0031] The first base wall 1a and the second base wall 1b are rectangular in shape when viewed along the Z direction, with the first base wall 1a forming the top wall of case 1 and the second base wall 1b forming the bottom wall of case 1.

[0032] Furthermore, the second case member 12 is substantially C-shaped when viewed along the X direction and includes a first side wall 1c and a second side wall 1d as side walls of case 1, with the first side wall 1c and the second side wall 1d facing each other in the Y direction.

[0033] Furthermore, the first end plate 13 includes a first end wall 1e positioned on the front side, and the second end plate 14 includes a second end wall 1f facing the first end wall 1e in the X direction. The second end wall 1f is positioned on the rear side.

[0034] The first base wall 1a, the second base wall 1b, the first side wall 1c, the second side wall 1d, the first end wall 1e, and the second end wall 1f define a space inside the case 1 for housing the fan 2, the voltage conversion circuit 3, and the battery assembly 4. In this embodiment, the fan 2, the battery assembly 4, and the voltage conversion circuit 3 are arranged in this order from the front along the X direction. However, the arrangement of the fan 2, the voltage conversion circuit 3, and the battery assembly 4 can be changed.

[0035] A first ventilation opening 15 is formed in the first end wall 1e, which is one end of case 1 in the X direction. A second ventilation opening 16 is formed in the second end wall 1f, which is the other end of case 1 in the X direction (see Figure 3). The first ventilation opening 15 and the second ventilation opening 16 are composed of a number of small holes that penetrate the walls, and they connect the outside of case 1 to the inside of case 1.

[0036] When fan 2 operates, it directs air from the outside to the inside of case 1 through one of the first vent 15 and the second vent 16. The air directed into case 1 flows along the X direction inside case 1 and is discharged to the outside of case 1 through the other of the first vent 15 and the second vent 16. The battery assembly 4 is cooled by heat exchange with the air flowing inside case 1.

[0037] Voltage conversion circuit 3 includes at least a DC-DC converter that converts one DC voltage to another, where "conversion" includes both boosting and bucking.

[0038] Referring to Figures 4 and 5, the battery assembly 4 includes a plurality of battery cells 5, a cell holder 6 that houses the plurality of battery cells 5, a heat conductive member 7 positioned above the cell holder 6, and a cover 8 positioned above the heat conductive member 7.

[0039] Referring to Figures 5 and 6, the battery cell 5 is a cylindrical lithium-ion secondary battery. As shown in Figure 6, the battery cell 5 includes a bottomed cylindrical outer casing 51 with one side open in the axial direction, and a sealing plate 52 that seals the opening of the outer casing 51. The outer casing 51 houses the electrode body (not shown) and the electrolyte (not shown).

[0040] The outer casing 51 and the sealing plate 52 are made of a conductive material. The sealing plate 52 is positioned on one side of the battery cell 5 in the axial direction and is attached to the outer casing 51 via an insulating material (not shown). Hereinafter, in the axial direction, the end face portion of the battery cell 5 on the side where the sealing plate 52 is positioned will be referred to as the first end face portion 5a, and the opposite end face portion will be referred to as the second end face portion 5b.

[0041] The sealing plate 52 has a thin-walled section with a reduced size (thickness) in the Z direction and includes a valve 53 (safety valve) that opens when the internal pressure of the outer can 51 rises. The valve 53 opens when gas is discharged. When the valve 53 opens, the gas generated in the battery cell 5 (inside the outer can 51) is discharged to the outside of the outer can 51. The gas discharged from the battery cell 5 is high temperature and high pressure. The gas generated from the battery cell 5 is discharged to the outside of the case 1 through the first vent 15 and the second vent 16.

[0042] The battery cell 5 further includes a central electrode 5c provided in the center of the first end face portion 5a, and a peripheral electrode 5d provided on the periphery of the first end face portion 5a. The central electrode 5c and the peripheral electrode 5d have opposite polarities. In this embodiment, the central electrode 5c is the positive electrode and the peripheral electrode 5d is the negative electrode, but the polarities of the central electrode 5c and the peripheral electrode 5d may be reversed.

[0043] Referring to Figure 5, the cell holder 6 holds multiple battery cells 5.

[0044] Multiple battery cells 5 are held in the cell holder 6 with their heights aligned so that their first end faces 5a (second end faces 5b) are on the same plane. The battery cells 5 are held in the cell holder 6 in a vertical orientation with their axial direction aligned with the Z direction, and with their first end faces 5a (sealing plates 52) facing downwards.

[0045] Multiple battery cells 5 are arranged in an alternating (staggered) pattern such that the interfaces of adjacent battery cells 5 in the Y direction are located between adjacent battery cells 5 in the X direction. In this embodiment, the multiple battery cells 5 are arranged to form 25 rows in the X direction and 4 rows in the Y direction. However, the arrangement of the battery cells 5 can be changed as appropriate.

[0046] The cell holder 6 is composed of a lower holder 6a and an upper holder 6b that are separable in the Z direction. Multiple battery cells 5 are placed between the lower holder 6a and the upper holder 6b, and are held by the cell holder 6 when the lower holder 6a and the upper holder 6b are integrated (see Figure 7).

[0047] The cell holder 6 includes a holder wall portion 61 made of an insulating material such as synthetic resin.

[0048] The holder wall 61 defines multiple storage spaces 62 (cell storage sections) for accommodating multiple battery cells 5. The storage spaces 62, when viewed along the Z-direction, have the same shape as the outer shape (circular) of the battery cell 5, or a shape corresponding to the contour of the battery cell 5. Each storage space 62 accommodates one battery cell 5.

[0049] Referring to Figure 7, a plurality of first exposure openings 61b are formed in the bottom wall 61a of the holder wall portion 61 (lower holder 6a). The first exposure openings 61b are positioned opposite the battery cell 5 housed in the housing space 62 in the Z direction, and connect the housing space 62 to the outside of the cell holder 6. At least a portion of the first end face portion 5a of the battery cell 5 placed in the housing space 62 (sealing plate 52 and valve 53) is exposed through the first exposure openings 61b.

[0050] In this embodiment, the battery assembly 4 employs a so-called single-sided current collection structure and further includes lead plates 50 that electrically connect a plurality of battery cells 5. The lead plates 50 are positioned below the bottom wall 61a of the holder wall portion 61 (lower holder 6a).

[0051] The lead plate 50 includes a plurality of through holes (hereinafter referred to as lead through holes 50a) that penetrate the lead plate 50 along the Z direction, and a plurality of lead wires 50b that are connected to the electrodes of each of the plurality of battery cells 5. The plurality of lead through holes 50a expose each of the plurality of battery cells 5. The lead wires 50b are connected to the electrodes of the battery cells 5 via the lead through holes 50a of the lead plate 50 and the first exposed opening 61b of the cell holder 6. The plurality of battery cells 5 that are electrically connected to each of the plurality of lead wires 50b contained in a single lead plate 50 are connected in parallel, for example. Furthermore, by electrically connecting the lead plates 50 to each other, the plurality of battery cells 5 are connected in parallel and in series. The lead plate 50 is electrically connected to the voltage conversion circuit 3 via a busbar (not shown), for example. As a result, the plurality of battery cells 5 are electrically connected to the voltage conversion circuit 3. The number of battery cells 5 that make up one parallel unit and the number of parallel units can be changed as appropriate.

[0052] Furthermore, the battery assembly 4 includes an insulating sheet 9 positioned below the lead plate 50 to ensure insulation, and a duct member 10 positioned between the insulating sheet 9 and the second base wall 1b of the second case member 12.

[0053] The insulating sheet 9 includes a sheet-like insulating base 91 and a through hole (hereinafter referred to as the insulating through hole 92) that penetrates the insulating base 91 along the Z direction. The insulating through hole 92 is arranged coaxially with the first exposed opening 61b.

[0054] The duct member 10 is made of sheet metal such as steel or aluminum alloy, and receives the gas ejected from the battery cell 5.

[0055] Furthermore, the cell holder 6 includes a positioning mechanism (not shown) that fixes the position of the holder wall portion 61 (bottom wall 61a) relative to the duct member 10. The positioning mechanism is, for example, a rib extending from the bottom wall 61a of the holder wall portion 61 toward the -Z side, which separates the duct member 10 and the cell holder 6. This defines a space (hereinafter referred to as the first duct space D1) between the holder wall portion 61 (bottom wall 61a) and the duct member 10 (upper surface). Air introduced from outside the case 1 and gas discharged from the battery cell 5 can flow through the first duct space D1.

[0056] Furthermore, as shown in Figure 8A, the upper part of the housing space 62 is open (see also Figure 5). Hereinafter, the open portion of the housing space 62 will be referred to as the second exposure opening 63. In this embodiment, the second exposure opening 63 is large enough to expose almost the entire second end face portion 5b of the battery cell 5 (see Figure 9).

[0057] Referring to Figure 9, the heat conductive member 7 is positioned (overlapped) on the upper surface of the battery cell 5 and cell holder 6 that are exposed from the second exposure opening 63.

[0058] The heat conductive member 7 is in thermal contact with the battery cell 5 and absorbs the heat generated from the battery cell 5. Here, "thermal contact" includes not only the case where "the heat conductive member 7 is in direct contact with the battery cell 5 and the heat from the battery cell 5 can be directly transferred to the heat conductive member 7 from the second end face portion 5b," but also the case where "the heat conductive member 7 is indirectly in contact with the battery cell 5 via the cell holder 6 and the heat from the battery cell 5 can be transferred to the heat conductive member 7 via the cell holder 6."

[0059] The heat conductive member 7 is composed of sheet-like members such as heat conductive sheets and thermal pads that have thermal conductivity.

[0060] In this embodiment, the heat conduction member 7 is composed of two thermal pads, which are arranged side by side along the X direction. However, the number and arrangement of the thermal pads are not particularly limited as long as they are in thermal contact with the battery cell 5. Hereinafter, one of the two thermal pads may be referred to as the first thermal pad 7a and the other as the second thermal pad 7b.

[0061] The first thermal pad 7a and the second thermal pad 7b have a sheet-like base (hereinafter referred to as the pad base 71). The pad base 71 is fishbone-shaped when viewed along the Z direction and is configured to efficiently contact multiple battery cells 5. Multiple through holes (hereinafter referred to as pad through holes 72) are formed in the pad base 71 that penetrate along the Z direction. In this embodiment, the pad base 71 of the first thermal pad 7a is larger in size in the X direction than the pad base 71 of the second thermal pad 7b, with six pad through holes 72 formed in the first thermal pad 7a and four pad through holes 72 formed in the second thermal pad 7b. The pad through holes 72 are rectangular when viewed along the Z direction.

[0062] Referring to Figure 5, the cover 8 is made of sheet metal such as steel or aluminum alloy. As shown in Figures 7 and 8A, the cover 8 is positioned on the upper surface of the heat conductive member 7 such that the thickness direction is in the Z direction.

[0063] More specifically, the cover 8 is positioned to overlap the cell holder 6 in the Z direction via the heat conductive member 7 (see Figure 5). In this embodiment, the cover 8 overlaps (completely covers) the entire upper surface of the cell holder 6 via the heat conductive member 7 when viewed along the Z direction. The cover 8 is positioned away from the first base wall 1a of the first case member 11 and is positioned to define a second duct space D2 between it and the first base wall 1a (lower surface).

[0064] The cover 8 is positioned on the side of the battery cell 5 opposite to the side where the valve 53 (sealing plate 52) is located (the first end face portion 5a). In other words, the valve 53 (sealing plate 52) of the battery cell 5 is positioned on the second end face portion 5b of the battery cell 5 that is furthest from the cover 8 in the Z direction (see Figure 7).

[0065] The cover 8 is fastened to the cell holder 6 by fastening members such as screws and bolts. As a result, the heat conductive member 7 is sandwiched (compressed) between the cell holder 6 and the cover 8.

[0066] Referring to Figure 10A, the cover 8 is rectangular when viewed along the Z direction and has four ends (sides). More specifically, the cover 8 has a first cover end 8a at one end (front end) in the X direction, a second cover end 8b at the other end (rear end) in the X direction, a third cover end 8c at one end in the Y direction, a fourth cover end 8d at the other end in the Y direction, and a center point 8e. The center point 8e is the point where the first center line CL1 and the second center line CL2 coincide. The first center line CL1 is a virtual line that passes through (connects) the midpoint of the third cover end 8c and the midpoint of the fourth cover end 8d in the X direction, and the second center line CL2 is a virtual line that passes through (connects) the midpoint of the first cover end 8a and the midpoint of the second cover end 8b in the Y direction.

[0067] As shown in Figures 11A and 11B, the cover 8 includes a cover base 81 and a plurality (10 in this embodiment) of restricting portions 82.

[0068] The multiple restricting sections 82 are so-called louvers, and are formed, for example, by cutting and shaping a part of the blank (material) of the cover 8. The multiple restricting sections 82 restrict the direction of flow of gas discharged from the battery cell 5. The restricting sections 82 guide (discharge) the gas toward the center of the cover 8 in the X direction (an example of the center in the second direction). The center of the cover 8 in the X direction is the part of the cover 8 that overlaps with the first center line CL1 (in this embodiment, the center point 8e).

[0069] As shown in Figure 11A, the multiple restricting portions 82 are arranged linearly along the X direction. In this embodiment, the multiple restricting portions 82 are arranged along the second center line CL2. That is, the multiple restricting portions 82 are located in the portion of the cover 8 that overlaps with the second center line CL2, and are positioned in the central part of the cover 8 in the Y direction (an example of the central part in the third direction).

[0070] Multiple regulating sections 82 are arranged at intervals in the X direction. The spacing between adjacent regulating sections 82 is configured to become narrower towards the side closer to the first center line CL1 in the central part of the cover 8 in the X direction.

[0071] More specifically, the first spacing G1 between two adjacent restricting sections 82 that are separated by the center point 8e is set to be narrower than the second spacing G2 between two adjacent restricting sections 82 that are positioned first and second closest to the center point 8e. Furthermore, the second spacing G2 is set to be narrower than the third spacing G3 between two adjacent restricting sections 82 that are positioned second and third closest to the center point 8e. Additionally, the third spacing G3 is set to be narrower than the fourth spacing G4 between two adjacent restricting sections 82 that are positioned third and fourth closest to the center point 8e, and the fourth spacing G4 is set to be narrower than the fifth spacing G5 between two adjacent restricting sections 82 that are positioned fourth and fifth closest to the center point 8e. In this embodiment, the two adjacent restricting portions 82 positioned near the fourth and fifth positions from the center point 8e are the two adjacent restricting portions 82 that are closest to the edge of the cover 8 (the first cover edge 8a or the second cover edge 8b). In other words, the first spacing G1 between two adjacent restricting portions 82 that are separated by the center point 8e is smaller than the fifth spacing G5 between two adjacent restricting portions 82 that are closest to the edge of the cover 8. For example, the first spacing G1 is less than or equal to half of the fifth spacing G5.

[0072] As shown in Figure 11B, each of the multiple restricting portions 82 is positioned to overlap with the pad through-holes 72 of the heat conductive member 7 when viewed along the Z direction. That is, the restricting portions 82 are positioned so as not to overlap with the pad base portions 71 of the heat conductive member 7. More specifically, the multiple pad through-holes 72 of the heat conductive member 7 are arranged linearly along the central position in the Y direction (between the two middle battery cells 5 of the four battery cells 5 arranged in the Y direction), and are arranged at the same interval as the multiple restricting portions 82 along the X direction (see Figure 11A).

[0073] As shown in Figure 8B, the restricting section 82 includes a communication opening 83 that communicates with the accommodation space 62, and a guide wall 84 that is positioned to cover at least a portion of the communication opening 83.

[0074] The communication opening 83 penetrates the cover base 81 along the Z direction and communicates with the housing space 62 through the pad through-hole 72 of the heat conductive member 7. In this embodiment, the communication opening 83 is smaller than the pad through-hole 72 when viewed along the Z direction, and the communication opening 83 has a combined shape of an elongated hole (with the Y direction as its longitudinal direction) and a rectangular hole (with the X direction as its short direction and the Y direction as its longitudinal direction) when viewed along the Z direction. The length of the rectangular hole in the Y direction is shorter than the length of the elongated hole (see Figure 10B).

[0075] The communication opening 83 is open at both ends in the Z direction; the -Z end is connected to the accommodation space 62, and the +Z end is connected to a guide space defined above the communication opening 83 by the guide wall 84.

[0076] Referring to Figure 10B, the guide wall portion 84 defines an opening 87 for releasing gas from the communication port 83.

[0077] The guide wall portion 84 is, for example, composed of a part of the periphery (cover base portion 81) that constitutes the communication opening 83 that is raised upward.

[0078] More specifically, the guide wall 84 includes a central guide wall 84a facing the communication opening 83 in the Z direction, and a pair of guide side walls 84b connected to both sides of the central guide wall 84a in the Y direction. The ends of the pair of guide side walls 84b opposite to the central guide wall 84a are connected to the cover base 81, and they extend continuously between the central guide wall 84a and the cover base 81.

[0079] The central guide wall 84a is connected to (continuous with) the cover base 81 on the side farther from the first center line CL1 (see Figure 10A), and separated from the cover base 81 on the side closer to the first center line CL1. In other words, a portion of the central guide wall 84a in the X direction is separated from the cover base 81, defining the guide space above the communication opening 83. The open opening 87 is the open end (the end closer to the first center line CL1) of the guide space defined by the guide wall portion 84 (the end of the guide wall portion 84 in the X direction). The open opening 87 is a trapezoidal YZ plane (a plane perpendicular to the X direction) when viewed along the X direction.

[0080] In other words, each of the multiple restricting sections 82 (guide wall sections 84) defines an opening 87 that faces the center of the cover 8 in the X direction (first center line CL1), and guides the gas to flow toward the center of the cover 8 in the X direction (first center line CL1).

[0081] In other words, as shown in Figure 11A, the multiple restricting units 82 are arranged point-symmetrically (line-symmetrically with respect to the first center line CL1) with respect to the center point 8e. Hereinafter, among the multiple restricting units 82, the restricting units 82 located on the +X side of the first center line CL1 will be referred to as the first restricting group 82a, and the restricting units 82 located on the -X side will be referred to as the second restricting group 82b.

[0082] All openings 87 of the restricting parts 82 constituting the first restricting group 82a and the second restricting group 82b are configured to face the center of the cover 8 (first center line CL1) in the X direction, and the multiple restricting parts 82 constituting the first restricting group 82a and the multiple restricting parts 82 constituting the second restricting group 82b are arranged so that their openings 87 face each other in the X direction. Specifically, all openings 87 of the multiple restricting parts 82 constituting the first restricting group 82a are configured to face the -X side, and all openings 87 of the multiple restricting parts 82 constituting the second restricting group 82b are configured to face the +X side.

[0083] As explained with reference to Figures 1 to 3, a first vent 15 is formed at one end (+X side) in the X direction of case 1, and a second vent 16 (see Figure 3) is formed at the other end (-X side). Therefore, all of the multiple restricting parts 82 constituting the first restricting group 82a are configured such that the opening 87 faces the second vent 16, and all of the multiple restricting parts 82 constituting the second restricting group 82b are configured such that the opening 87 faces the first vent 15 (see Figure 3).

[0084] The first vent 15 (the vent on the +X side) is a distal vent that is farther from the multiple regulating sections 82 that constitute the second regulating group 82b (the regulating section 82 on the -X side) of the first vent 15 and the second vent 16, and the second vent 16 (the vent on the -X side) is a distal vent that is farther from the multiple regulating sections 82 that constitute the first regulating group 82a (the regulating section 82 on the +X side) of the first vent 15 and the second vent 16.

[0085] In other words, the guide wall portion 84 of the multiple restricting portions 82 includes a central guide wall 84a (an example of a restricting wall) located on the side of the proximal vent, which is closer to the first vent 15 and the second vent 16, in the X direction, and the central guide wall 84a and a pair of guide side walls 84b define an opening 87 facing the distal vent. As a result, the gas is guided by the guide wall portion 84 toward the distal vent.

[0086] (Gas flow) In the battery module 100 configured as described above, as shown in Figure 7, when the pressure inside the outer casing 51 of the battery cell 5 increases and gas is generated from the battery cell 5, all or part of the gas flows downward through the containment space 62, passes through the first exposed opening 61b of the bottom wall 61a of the cell holder 6 and the lead through-holes 50a of the lead plate 50, and flows into the first duct space D1.

[0087] If only a portion of the gas flows downward through the containment space 62, as shown in Figure 8A, the remaining gas flows upward through the containment space 62 of the cell holder 6, passes through the second exposed opening 63 of the cell holder 6 and the pad through-hole 72 of the heat conduction member 7 to the cover 8, and is guided to the communication opening 83 of the restricting section 82 of the cover 8 (see Figure 8B). As shown in Figure 8B, the flow direction of the gas guided to the communication opening 83 of the restricting section 82 is restricted by the guide wall 84. Specifically, as shown in Figure 12, the gas is guided toward the center point 8e of the cover 8, that is, toward the distal vent on the farther side of the first vent 15 and the second vent 16, and flows through the second duct space D2.

[0088] The first duct space D1 and the second duct space D2 are in communication with the first vent 15 and the second vent 16, as described with reference to Figure 3. Therefore, gas flowing into the first duct space D1 and the second duct space D2 is discharged to the outside of case 1 through at least one of the first vent 15 and the second vent 16.

[0089] (Effects of the embodiment) According to the above embodiment, as shown in Figure 12, the openings 87 of all regulating parts 82 constituting the first regulating group 82a and the second regulating group 82b are configured to face the center of the cover 8 (center point 8e) in the X direction, and the multiple regulating parts 82 constituting the first regulating group 82a and the multiple regulating parts 82 constituting the second regulating group 82b are arranged so that their openings 87 face each other in the X direction. With this configuration, the gases discharged from the openings 87 of the multiple regulating parts 82 collide with each other, reducing the gas flow velocity. As a result, the residence time of the gas inside the case 1 can be increased. This reduces the pressure and temperature of the gas when it is discharged to the outside of the case 1, improving the safety of the battery module 100 and the area around the battery module 100. In addition, because there are multiple regulating parts 82, the gas discharge efficiency is also improved.

[0090] In other words, according to this embodiment, it is possible to provide a battery module 100 that achieves both improved gas discharge efficiency and improved safety of the battery module 100.

[0091] The above configuration may be modified as appropriate within the scope of this disclosure.

[0092] The number of regulating units 82 described in the above embodiment is not particularly limited, as long as it is a number that easily balances gas discharge efficiency and safety.

[0093] In the above embodiment, the multiple restricting portions 82 are arranged in the center in the Y direction, but the multiple restricting portions 82 do not have to be arranged in the center in the Y direction. Also, although the multiple restricting portions 82 are arranged in a single row along the X direction, the multiple restricting portions 82 may be arranged in multiple rows (for example, two rows) parallel to the Y direction.

[0094] Furthermore, the multiple restricting sections 82 do not necessarily have to be arranged in a straight line along the X direction; for example, they may be arranged alternately in a staggered pattern.

[0095] In the above embodiment, the spacing between adjacent restricting portions 82 in the X direction was set to be narrower on the side closer to the center point 8e of the cover 8. However, the spacing between adjacent restricting portions 82 in the X direction may be constant. Alternatively, it may be set to be wider on the side closer to the center point 8e of the cover 8.

[0096] In the above embodiment, the cover 8 may partially overlap with the pad base 71 of the heat conductive member 7. Furthermore, the cover 8 is not limited to covering the upper surface of the cell holder 6, but may also cover the lower surface or the sides.

[0097] The battery cell 5 described in the above embodiment may be a battery other than a lithium-ion secondary battery, such as an all-solid-state battery. Furthermore, the shape of the battery cell 5 is not limited to cylindrical; it may be a battery other than cylindrical, such as a prismatic shape. In addition, the arrangement of the battery cells 5 can be changed as appropriate.

[0098] Furthermore, in the above embodiment, a positive electrode and a negative electrode were provided on one end face (first end face 5a) of the battery cell 5. However, the battery cell 5 may have a positive electrode provided on one end face and a negative electrode provided on the other end face.

[0099] This disclosure may include the following aspects: (Aspect 1) Multiple battery cells, A cell holder including a housing space for housing multiple battery cells, A cover positioned so as to overlap the cell holder when viewed along the first direction, Equipped with, The cover includes a plurality of restricting sections that restrict the flow direction of gas discharged from the battery cell, The regulating portion is a battery module that guides the gas toward the central part of the cover in a second direction perpendicular to the first direction. (Aspect 2) The battery module according to embodiment 1, wherein the plurality of regulating portions are arranged at intervals in the second direction. (Aspect 3) The battery module according to embodiment 2, wherein the spacing between adjacent restricting portions is narrower on the side closer to the center of the cover in the second direction. (Aspect 4) The battery module according to embodiment 2 or 3, wherein the plurality of regulating portions are arranged linearly along the second direction. (Aspect 5) The battery module according to any one of embodiments 1 to 4, wherein the plurality of regulating portions are arranged in the center of a third direction perpendicular to the first and second directions. (Aspect 6) The device further comprises a case for housing multiple battery cells, cell holders, and covers, The aforementioned case is, A first vent is formed at one end in the second direction, through which the gas can pass, A second vent is formed at the other end in the second direction, through which the gas can pass, and Includes, The aforementioned regulatory body, A communication opening that communicates with the aforementioned storage space, A guide wall portion is positioned to cover at least a portion of the communication opening and defines an opening for releasing the gas from the communication opening. Includes, The battery module according to any one of embodiments 1 to 5, wherein the guide wall defines the opening so that it faces the distal vent on the farther side of the first vent and the second vent. (Aspect 7) The device further comprises a case for housing multiple battery cells, cell holders, and covers, The aforementioned case is, A first vent is formed at one end in the second direction, through which the gas can pass, A second vent is formed at the other end in the second direction, through which the gas can pass, and Includes, The regulating portion includes a communication opening that communicates with the containment space, and a guide wall portion that is arranged to cover at least a part of the communication opening and defines an opening for releasing the gas from the communication opening. The battery module according to any one of embodiments 1 to 5, wherein the guide wall portion includes a regulating wall positioned on the side of the proximal vent that is closer to the first vent and the second vent. (Pattern 8) The cell holder and the cover are further provided with a heat conductive member, The heat conductive member includes a sheet-like base, A battery module according to any one of embodiments 1 to 7, wherein, viewed along the first direction, the restricting portion is arranged to overlap with a through hole penetrating the base. [Explanation of Symbols]

[0100] 1 case 1a. First base wall 1b Second base wall 1c 1st side wall 1d Second side wall 1e First end wall 1st floor, second end wall 2 Fans 3. Voltage conversion circuit 4. Battery Assembly 5 battery cells 5a First end section 5b Second end face part 5c center electrode 5d peripheral electrode 6 Cell holder 6a Lower holder 6b Upper holder 7. Heat conductive material 7a First Thermal Pad 7b Second Thermal Pad 8 Covers 8a First cover end 8b Second cover end 8c Third cover end 8d Fourth cover end 8e center point 9. Insulating sheet 10 Duct components 11. First case component 12. Second case component 13. First End Plate 14. Second end plate 15. First ventilation opening 16. Second ventilation opening 50 Lead Plates 50a Lead through hole 50b Lead wire 51 Outer can 52 Sealing plate 53 valves 61 Holder wall 61a Bottom wall 61b 1st exposure port 62 Containment space 63 2nd exposure port 71 Pad base 72 pad through holes 81 Cover base 82 Regulatory Department 82a Group 1 of regulations 82b Second Regulatory Group 83 Connecting Port 84 Guide wall section 84a Guide Central Wall 84b Guide sidewall 87 Open mouth 91 Insulating base 92 Insulation through-holes 100 Battery Modules CL1 1st Center Line CL2 2nd Center Line D1 First duct space D2 Second duct space

Claims

1. Multiple battery cells, A cell holder including a housing space for housing the plurality of battery cells, A cover positioned so as to overlap the cell holder when viewed along the first direction, Equipped with, The cover includes a plurality of restricting sections that restrict the flow direction of gas discharged from the battery cell, The plurality of restricting portions guide the gas discharged from the battery cell toward the central part of the cover in a second direction perpendicular to the first direction. The plurality of restricting parts are arranged at intervals in the second direction, A battery module in which the distance between two adjacent regulating portions is narrower on the side closer to the center of the cover in the second direction.

2. Multiple battery cells, A cell holder including a housing space for housing the plurality of battery cells, A cover positioned so as to overlap the cell holder when viewed along the first direction, Equipped with, The cover includes a plurality of restricting sections that restrict the flow direction of gas discharged from the battery cell, The plurality of restricting portions guide the gas discharged from the battery cell toward the central part of the cover in a second direction perpendicular to the first direction. The case further comprises the plurality of battery cells, the cell holder, and the cover, The aforementioned case is, A first vent is formed at one end in the second direction, through which gas discharged from the battery cell can pass, A second vent is formed at the other end in the second direction, through which gas discharged from the battery cell can pass. Includes, Each of the aforementioned multiple regulatory units is: A communication opening that communicates with the aforementioned storage space, A guide wall portion is positioned to cover at least a portion of the communication port and defines an opening for releasing gas discharged from the battery cell through the communication port. Includes, The battery module has a guide wall portion that defines the opening so that it faces the distal vent, which is the farther of the first and second vents.

3. Multiple battery cells, A cell holder including a housing space for housing the plurality of battery cells, A cover positioned so as to overlap the cell holder when viewed along the first direction, Equipped with, The cover includes a plurality of restricting sections that restrict the flow direction of gas discharged from the battery cell, The plurality of restricting portions guide the gas discharged from the battery cell toward the central part of the cover in a second direction perpendicular to the first direction. The cell holder and the cover are further provided with a heat conductive member, The heat conductive member includes a sheet-like base, A battery module in which, when viewed along the first direction, each of the plurality of restricting portions is arranged to overlap with a through hole that penetrates the base.

4. Multiple battery cells, A cell holder including a housing space for housing the plurality of battery cells, A cover is positioned so as to overlap the cell holder when viewed along the first direction, A case that houses the plurality of battery cells, the cell holder, and the cover. Equipped with, The cover includes a plurality of restricting sections that restrict the flow direction of gas discharged from the battery cell, The plurality of restricting portions guide the gas discharged from the battery cell toward the central part of the cover in a second direction perpendicular to the first direction. Each of the aforementioned regulatory units is: A communication opening that communicates with the aforementioned storage space, A guide central wall is positioned to cover at least a portion of the aforementioned communication opening. It has, The battery module, in which the central wall of the guide and the case overlap when viewed along the first direction.

5. The battery module according to claim 4, wherein the case has a space between it and the cover and between it and the central wall of the guide.

6. The battery module according to any one of claims 1 to 5, wherein the plurality of restricting parts are arranged linearly along the second direction.

7. The battery module according to any one of claims 1 to 5, wherein the plurality of restricting portions are arranged in the center of a third direction perpendicular to the first and second directions.

8. The case further comprises the plurality of battery cells, the cell holder, and the cover, The aforementioned case is, A first vent is formed at one end in the second direction, through which gas discharged from the battery cell can pass, A second vent is formed at the other end in the second direction, through which gas discharged from the battery cell can pass. Includes, Each of the plurality of restricting sections includes a communication opening that communicates with the containment space, and a guide wall section that is positioned to cover at least a portion of the communication opening and defines an opening for releasing gas discharged from the battery cell through the communication opening. The battery module according to claim 1, wherein the guide wall portion includes a regulating wall positioned on the side of the proximal vent that is closer to the first vent and the second vent.

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