Battery module

Abstract

A battery module (10) comprises: a battery cell (100); and a housing body (500) that accommodates the battery cell (100). The housing body (500) has: a metal plate (512) and an insulating heat-resistant sheet (516) that respectively define a first external hole (H11) and a first intermediate hole (H21); and an insulating sheet (514) that defines a first internal hole (H31) overlapping with the first external hole (H11) and the first intermediate hole (H21). The area of the first internal hole (H31) is smaller than the area of each of the first external hole (H11) and the first intermediate hole (H21).

Description

Battery module

[0001] This invention relates to a battery module.

[0002] In recent years, various battery modules have been developed. A battery module consists of battery cells and a housing that encloses the battery cells.

[0003] Patent Document 1 describes a battery pack. The battery pack comprises a battery and an electronic device case that houses the battery. The electronic device case has a ventilation section. The ventilation section has an outer wall section with a plurality of ventilation holes and an inner wall section with ventilation holes arranged alternately with respect to the ventilation holes in the outer wall section.

[0004] Patent Document 2 describes a battery pack. The battery pack comprises battery cells, a case for housing the battery cells, and a plurality of perforated plates that close the openings provided in the case. Each perforated plate has a plurality of smoke exhaust holes. The plurality of perforated plates are stacked in such a way that the smoke exhaust holes of overlapping perforated plates do not face each other.

[0005] International Publication No. 2017 / 073201, International Publication No. 2020 / 152992

[0006] In a battery module, the housing that contains the battery cells may have gas exhaust ports, such as holes or thin-walled sections, for discharging various gases, including gases generated from the battery cells. In a battery module, it is sometimes required to achieve both electrical insulation of the battery cells from the outside of the housing and efficient gas discharge to the outside of the housing.

[0007] One example of the object of the present invention is to achieve both electrical insulation of the battery cells from the outside of the housing and efficient discharge of gas to the outside of the housing. Other objects of the present invention will become apparent from the description herein.

[0008] An aspect of the present invention is as follows: 1. A battery module comprising: a battery cell; and a housing that houses the battery cell, wherein the housing has a first portion that defines a first gas exhaust section and a second portion that defines a second gas exhaust section that overlaps the first gas exhaust section and has electrical insulation, wherein the area of ​​the second gas exhaust section is smaller than the area of ​​the first gas exhaust section. 2. The battery module described in 1., further comprising a partition wall that is located at least partially between the battery cell and the second gas exhaust section. 3. The battery module described in 2., wherein the first gas exhaust section and a portion of the battery cell that is exposed from the partition wall at least partially overlap each other. 4. The battery module described in 2. or 3., further comprising: a voltage detection section that detects the voltage of the battery cell; and a holder that at least partially holds the voltage detection section, wherein the holder has the partition. 5. The battery module described in any one of 1. to 4., wherein the second portion is located between the battery cell and the first portion. 6. The battery module according to any one of 1. to 5., wherein the first portion includes at least one of a metal and a heat-resistant material. 7. The battery module according to any one of 1. to 6., wherein the first gas discharge portion has at least one of a hole penetrating the first portion and a thin-walled portion of the first portion, and the second gas discharge portion has at least one of a hole penetrating the second portion and a thin-walled portion of the second portion.

[0009] According to the above aspect of the present invention, it is possible to achieve both electrical insulation of the battery cells from the outside of the housing and efficient discharge of gas to the outside of the housing.

[0010] This is an exploded perspective view of a battery module according to an embodiment. This is a perspective view of a first plate according to an embodiment. This is an exploded front view of a first voltage detection device and a first plate according to an embodiment.

[0011] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted where appropriate.

[0012] FIG. 1 is an exploded perspective view of a battery module 10 according to an embodiment.

[0013] For the purpose of explanation, the X direction, Y direction, and Z direction are shown in FIG. 1 and subsequent figures. The X direction indicates the front-to-rear direction of the battery module 10. The Y direction is one of the directions perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery module 10. The Z direction is a direction perpendicular to both the X direction and the Y direction. The Z direction indicates the up-to-down direction of the battery module 10. The arrow pointing to the X direction, the arrow pointing to the Y direction, and the arrow pointing to the Z direction indicate the front, left, and up directions of the battery module 10, respectively. The relationship between the X direction, Y direction, and Z direction and the front-to-rear direction, left-to-right direction, and up-to-down direction of the battery module 10 is not limited to this example.

[0014] Hereinafter, as needed, the side indicated by the arrow indicating the X direction will be referred to as the +X side, and the side opposite the side indicated by the arrow indicating the X direction will be referred to as the -X side. Hereinafter, as needed, the side indicated by the arrow indicating the Y direction will be referred to as the +Y side, and the side opposite the side indicated by the arrow indicating the Y direction will be referred to as the -Y side. Hereinafter, as needed, the side indicated by the arrow indicating the Z direction will be referred to as the +Z side, and the side opposite the side indicated by the arrow indicating the Z direction will be referred to as the -Z side.

[0015] A battery module 10 according to an embodiment will be described with reference to Fig. 1. As shown in Fig. 1, the battery module 10 includes a plurality of battery cells 100, a plurality of compression pads 110, a first voltage detection device 200, a second voltage detection device 300, a first bus bar 410, a second bus bar 420, and a housing 500.

[0016] The multiple battery cells 100 are stacked in the Y direction with compression pads 110 disposed between adjacent battery cells 100. Hereinafter, as necessary, the multiple battery cells 100 and multiple compression pads 110 stacked alternately in the Y direction will be referred to as a stack of battery cells 100. The dimension of each battery cell 100 in the X direction is the dimension in the longitudinal direction of each battery cell 100. The dimension of each battery cell 100 in the Z direction is the dimension in the lateral direction of each battery cell 100. The dimension of each battery cell 100 in the Y direction is the dimension in the thickness direction of each battery cell 100. The shape of each battery cell 100 is not limited to this example.

[0017] Each battery cell 100 includes a battery element (not shown), an casing 102, a positive electrode tab 104, and a negative electrode tab 106. In one example, the battery element includes a plurality of positive and negative electrodes (not shown) stacked alternately in the Y direction, and a separator (not shown) located between adjacent positive and negative electrodes in the Y direction. The casing 102 seals the battery element and an electrolyte (not shown). The positive electrode tab 104 is electrically connected to the positive electrode of the battery element. The positive electrode tab 104 is drawn out from one of the sides of the casing 102 in the X direction. The negative electrode tab 106 is electrically connected to the negative electrode of the battery element. The negative electrode tab 106 is drawn out from the other side of the casing 102 in the X direction. However, the structure of each battery cell 100 is not limited to this example.

[0018] Each battery cell 100 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in a portion corresponding to a separator. An all-solid-state battery does not contain an electrolytic solution. Unless otherwise specified, the following description will be given assuming that each battery cell 100 is a battery cell containing an electrolytic solution.

[0019] The multiple battery cells 100 are electrically connected in a series-parallel combination. Specifically, cell groups including at least two battery cells 100 adjacent to each other in the Y direction and connected in parallel are stacked in the Y direction and connected in series. On the +X side of the stack of battery cells 100, a positive electrode tab 104 drawn from a battery cell 100 of one cell group connected in parallel and a negative electrode tab 106 drawn from a battery cell 100 of another cell group connected in parallel are electrically connected to each other, forming a tab group 108 including the positive electrode tab 104 and the negative electrode tab 106. The positive electrode tab 104 and the negative electrode tab 106 in the tab group 108 are joined to each other by, for example, laser welding. A tab group 108 is also located on the −X side of the stack of battery cells 100. Thus, multiple cell groups are connected in series from the cell group located at one end of the stack of battery cells 100 in the Y direction to the cell group located at the other end of the stack of battery cells 100 in the Y direction. Hereinafter, as necessary, the tab group 108 located on the +X side of the stack of battery cells 100 will be referred to as the +X side tab group 108, and the tab group 108 located on the −X side of the stack of battery cells 100 will be referred to as the −X side tab group 108.

[0020] The electrical connection of the plurality of battery cells 100 is not limited to the above example. For example, a stack of battery cells 100 may be formed by connecting single battery cells 100 in series.

[0021] The first voltage detection device 200 is configured to detect the voltages of the plurality of +X side tab groups 108. The first voltage detection device 200 has a first harness 210 and a first protector 220. The first harness 210 includes a plurality of first voltage detection terminals 212, a plurality of first voltage detection lines 214, and a first connector 216.

[0022] The first harness 210 is a voltage detection unit for detecting the voltage of a plurality of +X-side tab groups 108. The plurality of first voltage detection terminals 212 are arranged offset from each other in the Y direction. Each of the plurality of first voltage detection terminals 212 is located on the +X side with respect to each of the plurality of +X-side tab groups 108. Each first voltage detection terminal 212 is a conductive material such as metal. The -X side surface of each first voltage detection terminal 212 and the +X side surface of each +X-side tab group 108 are joined to each other by a joining method such as laser welding. Therefore, each first voltage detection terminal 212 and each +X-side tab group 108 are electrically connected to each other. One end of each first voltage detection line 214 and each first voltage detection terminal 212 are electrically connected to each other. The other end of each first voltage detection line 214 and the first connector 216 are electrically connected to each other.

[0023] The first protector 220 is a holder that holds the first harness 210 at least partially. The first protector 220 covers the +X side portion of the battery cell 100 laminate with a plurality of +X side tab groups 108 exposed through a plurality of first openings 222 provided in the first protector 220. The first protector 220 is an insulator such as resin. The plurality of first voltage detection terminals 212 and the first protector 220 are at least partially attached to each other. Inside the housing 500, the plurality of first voltage detection lines 214 are routed at least partially via the first protector 220. The first protector 220 holds the first harness 210 at least partially with the plurality of first voltage detection terminals 212 and the first protector 220 at least partially attached to each other, and the plurality of first voltage detection lines 214 are routed at least partially via the first voltage detection device 200. Therefore, by placing the first protector 220 at an appropriate position relative to the stack of battery cells 100, each of the multiple first voltage detection terminals 212 can be positioned at an appropriate position relative to each of the multiple +X side tab groups 108.

[0024] The voltage detection unit for detecting the voltage of the plurality of +X side tab groups 108 may have a structure different from that of the first harness 210 according to the embodiment, as long as it can detect the voltage of the plurality of +X side tab groups 108. The holder that at least partially holds the voltage detection unit may have a structure different from that of the first protector 220 according to the embodiment, as long as it can at least partially hold the voltage detection unit.

[0025] The second voltage detection device 300 is configured to detect the voltages of the multiple -X side tab groups 108. When viewed from the Z direction, the first voltage detection device 200 and the second voltage detection device 300 are substantially rotationally symmetric with respect to the center of the stack of battery cells 100.

[0026] The second voltage detection device 300 has a second harness 310 and a second protector 320, similar to the first voltage detection device 200. The second harness 310 and the second protector 320 can be substantially identical to the first harness 210 and the first protector 220, respectively, but do not need to be exactly the same. The second harness 310 includes a plurality of second voltage detection terminals 312, a plurality of second voltage detection lines 314, and a second connector 316, similar to the first harness 210. The plurality of second voltage detection terminals 312, a plurality of second voltage detection lines 314, and the second connector 316 can be substantially identical to the plurality of first voltage detection terminals 212, a plurality of first voltage detection lines 214, and the first connector 216, respectively, but do not need to be exactly the same. The specifications such as the material and shape of each component of the first voltage detection device 200 and the specifications such as the material and shape of each component of the second voltage detection device 300 may differ from each other depending on the conditions of the first voltage detection device 200 and the conditions of the second voltage detection device 300.

[0027] The first bus bar 410 is disposed at the +Y side end of the first protector 220. The first bus bar 410 is electrically connected to the positive electrode tabs 104 that are drawn out to the +X side from the battery cells 100 of the cell group located at the +Y side end of the stack of battery cells 100. The first bus bar 410 functions as an external terminal for electrically connecting the battery module 10 to an external device such as another battery module.

[0028] The second bus bar 420 is disposed at the -Y side end of the second protector 320. The second bus bar 420 is electrically connected to the negative electrode tab 106 that is drawn out to the -X side from the battery cell 100 of the cell group located at the -Y side end of the stack of battery cells 100. The second bus bar 420 functions as an external terminal for electrically connecting the battery module 10 to an external device such as another battery module.

[0029] 1 , the positive electrode tab 104 at the end of a group of multiple cells connected in series is drawn out toward the +X side from the battery cell 100 of the cell group located at the end on the +Y side of the stack of battery cells 100, and the negative electrode tab 106 at the end of a group of multiple cells connected in series is drawn out toward the −X side from the battery cell 100 of the cell group located at the end on the −Y side of the stack of battery cells 100. Thus, the first bus bar 410 is disposed on the +X side and +Y side of the stack of battery cells 100, and the second bus bar 420 is disposed on the −X side and −Y side of the stack of battery cells 100. However, the arrangement of the positive electrode tab 104 and the negative electrode tab 106 at the end of a group of multiple cells connected in series may differ depending on the number of battery cells 100 included in the stack of battery cells 100. For example, there may be a case where the positive electrode tab 104 at the end of a group of multiple cells connected in series is pulled out toward the +X side from the battery cell 100 of the cell group located at the end on the +Y side of the stack of battery cells 100, and the negative electrode tab 106 at the end of a group of multiple cells connected in series is pulled out toward the +X side from the battery cell 100 of the cell group located at the end on the -Y side of the stack of battery cells 100. In this case, the first bus bar 410 is arranged on the +X side and the +Y side of the stack of battery cells 100, and the second bus bar 420 is arranged on the +X side and the -Y side of the stack of battery cells 100.

[0030] The housing 500 houses a stack of battery cells 100. Unless otherwise specified, hereinafter, the inner space of the housing 500 refers to the space that houses the stack of battery cells 100 in the housing 500, and the outer space of the housing 500 refers to the space that exists outside the inner space of the housing 500 with respect to the housing 500. The housing 500 has a first plate 510, a second plate 520, a third plate 530, a fourth plate 540, a fifth plate 550, and a sixth plate 560.

[0031] The first plate 510 covers the +X side portion of the stack of battery cells 100 with the first voltage detection device 200 positioned between the stack of battery cells 100 and the first plate 510. The second plate 520 covers the -X side portion of the stack of battery cells 100 with the second voltage detection device 300 positioned between the stack of battery cells 100 and the second plate 520. The third plate 530 covers the +Y side portion of the stack of battery cells 100. The fourth plate 540 covers the -Y side portion of the stack of battery cells 100. The fifth plate 550 covers the +Z side portion of the stack of battery cells 100. The sixth plate 560 covers the -Z side portion of the stack of battery cells 100.

[0032] Fig. 2 is a perspective view of the first plate 510 according to the embodiment. Fig. 3 is an exploded front view of the first voltage detection device 200 and the first plate 510 according to the embodiment. For the sake of explanation, the first harness 210 has been removed from Fig. 3. In Fig. 3, the white circle with a black dot indicating the X direction indicates that the arrow indicating the X direction is facing towards the front of the page.

[0033] 2 and 3 , the first voltage detection device 200 and the first plate 510 according to the embodiment will be described. The matters described regarding the first voltage detection device 200 and the first plate 510 are also applicable to the second voltage detection device 300 and the second plate 520.

[0034] 3, the first plate 510 includes a metal plate 512, an insulating sheet 514, and an insulating heat-resistant sheet 516. The first plate 510 may include only one of the insulating sheet 514 and the insulating heat-resistant sheet 516. The insulating heat-resistant sheet 516 is located between the metal plate 512 and the insulating sheet 514 in the X direction, with the metal plate 512 located on the +X side of the insulating heat-resistant sheet 516 and the insulating sheet 514 located on the −X side of the metal plate 512. In other words, the metal plate 512 is located on the outer space side of the housing 500 with respect to the insulating heat-resistant sheet 516, and the insulating sheet 514 is located on the inner space side of the housing 500 with respect to the insulating heat-resistant sheet 516. In Figure 3, the first voltage detection device 200, the metal plate 512, the insulating sheet 514, and the insulating heat-resistant sheet 516 are aligned in the Y direction, but offset from each other in the Z direction.

[0035] The metal plate 512 is disposed approximately perpendicular to the X direction. When viewed from the X direction, the metal plate 512 has an approximately rectangular shape with a pair of long sides approximately parallel to the Y direction and a pair of short sides approximately parallel to the Z direction. The metal plate 512 is conductive. The metal plate 512 contains a metal. The metal plate 512 is made of a metal such as aluminum or stainless steel. By using the metal plate 512, the rigidity of the first plate 510 can be improved.

[0036] The insulating sheet 514 is disposed approximately perpendicular to the X direction. When viewed from the X direction, the insulating sheet 514 has a generally rectangular shape with a pair of long sides approximately parallel to the Y direction and a pair of short sides approximately parallel to the Z direction. The insulating sheet 514 has electrical insulation properties. The insulating sheet 514 is made of a resin such as polypropylene (PP). By positioning the insulating sheet 514 between the stack of battery cells 100 and the metal plate 512, the stack of battery cells 100 and the stack of battery cells 100 can be electrically insulated from each other.

[0037] The insulating heat-resistant sheet 516 is disposed approximately perpendicular to the X direction. When viewed from the X direction, the insulating heat-resistant sheet 516 has a substantially rectangular shape with a pair of long sides approximately parallel to the Y direction and a pair of short sides approximately parallel to the Z direction. The insulating heat-resistant sheet 516 has electrical insulation properties and heat resistance. The heat resistance of the insulating heat-resistant sheet 516 is higher than that of the insulating sheet 514, for example. The insulating heat-resistant sheet 516 contains a heat-resistant material such as silicon fiber. The heat resistance of the insulating heat-resistant sheet 516 can be improved by including a heat-resistant material therein. The insulating heat-resistant sheet 516 may also have fire resistance.

[0038] 2, the +Z side portion of the -Y side portion of the insulating heat-resistant sheet 516 has a first folded portion 516a folded back toward the +X side surface of the metal plate 512. In the example shown in Fig. 2, the +Z side portion of the +Y side portion of the insulating heat-resistant sheet 516 has a second folded portion 516b folded back toward the +X side surface of the metal plate 512. The first folded portion 516a and the second folded portion 516b do not have to be provided.

[0039] 2 and 3, the metal plate 512 defines a first external hole H11, a second external hole H12, a third external hole H13, a fourth external hole H14, a fifth external hole H15, a sixth external hole H16, and a seventh external hole H17. As shown in FIGS. 2 and 3, the insulating heat-resistant sheet 516 defines a first intermediate hole H21, a second intermediate hole H22, a third intermediate hole H23, a fourth intermediate hole H24, a fifth intermediate hole H25, a sixth intermediate hole H26, and a seventh intermediate hole H27. As shown in FIGS. 2 and 3, the insulating sheet 514 defines a first internal hole H31, a second internal hole H32, a third internal hole H33, a fourth internal hole H34, a fifth internal hole H35, a sixth internal hole H36, a seventh internal hole H37, and an eighth internal hole H38.

[0040] Hereinafter, unless otherwise specified, the first external hole H11 to the seventh external hole H17 collectively refer to the first external hole H11, the second external hole H12, the third external hole H13, the fourth external hole H14, the fifth external hole H15, the sixth external hole H16, and the seventh external hole H17, the first external hole H11 to the fourth external hole H14 collectively refer to the first external hole H11, the second external hole H12, the third external hole H13, and the fourth external hole H14, and the fifth external hole H15 to the seventh external hole H17 collectively refer to the fifth external hole H15, the sixth external hole H16, and the seventh external hole H17. The first external hole H11 to the seventh external hole H17 penetrate the metal plate 512 in the X direction. Unless otherwise specified, the area of ​​each of the first to seventh external holes H11 to H17 refers to the area of ​​the first to seventh external holes H11 to H17 perpendicular to the X direction.

[0041] Hereinafter, unless otherwise specified, the first intermediate hole H21 to the seventh intermediate hole H27 collectively refer to the first intermediate hole H21, the second intermediate hole H22, the third intermediate hole H23, the fourth intermediate hole H24, the fifth intermediate hole H25, the sixth intermediate hole H26, and the seventh intermediate hole H27, the first intermediate hole H21 to the fourth intermediate hole H24 collectively refer to the first intermediate hole H21, the second intermediate hole H22, the third intermediate hole H23, and the fourth intermediate hole H24, and the fifth intermediate hole H25 to the seventh intermediate hole H27 collectively refer to the fifth intermediate hole H25, the sixth intermediate hole H26, and the seventh intermediate hole H27. The first intermediate holes H21 to the seventh intermediate holes H27 penetrate the insulating heat-resistant sheet 516 in the X direction. Hereinafter, unless otherwise specified, the area of ​​each of the first intermediate hole H21 to the seventh intermediate hole H27 refers to the area perpendicular to the X direction of each of the first intermediate hole H21 to the seventh intermediate hole H27.

[0042] Hereinafter, unless otherwise specified, the first internal hole H31 to the eighth internal hole H38 are a collective term for the first internal hole H31, the second internal hole H32, the third internal hole H33, the fourth internal hole H34, the fifth internal hole H35, the sixth internal hole H36, the seventh internal hole H37, and the eighth internal hole H38. The first internal hole H31 to the eighth internal hole H38 penetrate the insulating sheet 514 in the X direction. Hereinafter, unless otherwise specified, the area of ​​each of the first internal hole H31 to the eighth internal hole H38 refers to the area perpendicular to the X direction of each of the first internal hole H31 to the eighth internal hole H38.

[0043] The first external hole H11 to the seventh external hole H17, the first intermediate hole H21 to the seventh intermediate hole H27, and the first internal hole H31 to the eighth internal hole H38 shown in Figures 2 and 3 will now be described. The first external hole H11 to the seventh external hole H17, the first intermediate hole H21 to the seventh intermediate hole H27, and the first internal hole H31 to the eighth internal hole H38 shown in Figures 2 and 3 are examples of holes provided in the metal plate 512, the insulating sheet 514, and the insulating heat-resistant sheet 516. The number, shape, and arrangement of the holes provided in the metal plate 512, the insulating sheet 514, and the insulating heat-resistant sheet 516 are not limited to the examples shown in Figures 2 and 3, and other examples are also possible.

[0044] The first external hole H11 to the fourth external hole H14 are lined up in the Y direction toward the +Y side in the order of first external hole H11, second external hole H12, third external hole H13, and fourth external hole H14. The first external hole H11, second external hole H12, and third external hole H13 are located on the -Y side of the metal plate 512. The fifth external hole H15 to the seventh external hole H17 are located on the -Z side relative to the first external hole H11 to the fourth external hole H14. The fifth external hole H15 to the seventh external hole H17 are lined up in the Y direction toward the +Y side in the order of fifth external hole H15, sixth external hole H16, and seventh external hole H17. The area of ​​each of the fifth external hole H15 to seventh external hole H17 is smaller than the area of ​​each of the first external hole H11 to fourth external hole H14.

[0045] When viewed from the X direction, the first intermediate hole H21, the second intermediate hole H22, the third intermediate hole H23, the fourth intermediate hole H24, the fifth intermediate hole H25, the sixth intermediate hole H26 and the seventh intermediate hole H27 have approximately the same shape as the first external hole H11, the second external hole H12, the third external hole H13, the fourth external hole H14, the fifth external hole H15, the sixth external hole H16 and the seventh external hole H17, respectively. When the metal plate 512 and the insulating heat-resistant sheet 516 are overlapped with each other in the X direction, the first intermediate hole H21, the second intermediate hole H22, the third intermediate hole H23, the fourth intermediate hole H24, the fifth intermediate hole H25, the sixth intermediate hole H26 and the seventh intermediate hole H27 each overlap almost entirely with the first external hole H11, the second external hole H12, the third external hole H13, the fourth external hole H14, the fifth external hole H15, the sixth external hole H16 and the seventh external hole H17, respectively.

[0046] When viewed from the X direction, each of the first to eighth internal holes H31 to H38 has a substantially circular shape. The area of ​​each of the first to eighth internal holes H31 to H38 is smaller than the area of ​​each of the first to seventh external holes H11 to H17 and the first to seventh intermediate holes H21 to H27.

[0047] When the metal plate 512, insulating sheet 514, and insulating heat-resistant sheet 516 are arranged in an X-direction, the relationships between the first external holes H11 to the seventh external holes H17, the first intermediate holes H21 to the seventh intermediate holes H27, and the first internal holes H31 to the eighth internal holes H38 are as follows: The first internal hole H31, the first external hole H11, and the first intermediate hole H21 overlap each other in the X-direction. The second internal hole H32, the second external hole H12, and the second intermediate hole H22 overlap each other in the X-direction. The third internal hole H33, the third intermediate hole H23, and the third internal hole H33 overlap each other in the X-direction. The fourth internal hole H34, the fourth external hole H14, and the fourth intermediate hole H24 overlap each other in the X-direction. The fifth internal hole H35, the fourth external hole H14, and the fourth intermediate hole H24 overlap each other in the X-direction. The sixth internal hole H36, the fifth external hole H15, and the fifth intermediate hole H25 overlap each other in the X direction. The seventh internal hole H37, the sixth external hole H16, and the sixth intermediate hole H26 overlap each other in the X direction. The eighth internal hole H38, the seventh external hole H17, and the seventh intermediate hole H27 overlap each other in the X direction.

[0048] The relationship between the first outer hole H11, the first intermediate hole H21, and the first inner hole H31 will be described.

[0049] In this embodiment, when the battery module 10 is operating normally, the inner space of the housing 500 and the outer space of the housing 500 communicate with each other through the first internal hole H31. Therefore, compared to the case where the area of ​​the first internal hole H31 is relatively large and equal to the area of ​​the first external hole H11 and the first intermediate hole H21, the exposure of the stack of battery cells 100 to the outer space of the housing 500 through the first internal hole H31 can be reduced when the battery module 10 is operating normally, and the battery cells 100 can be electrically insulated from the outside of the housing 500.

[0050] In this embodiment, if an abnormality occurs in the battery module 10 and relatively high-temperature gas is generated from the battery cell 100, the area around the first internal hole H31 of the insulating sheet 514 melts due to the gas, increasing the area of ​​the first internal hole H31. When gas is generated from the battery cell 100, the first external hole H11, the first intermediate hole H21, and the first internal hole H31 function as gas discharge sections for discharging the gas generated from the battery cell 100 towards the space outside the housing 500. Even if the area around the first external hole H11 of the metal plate 512 and the area around the first intermediate hole H21 of the insulating heat-resistant sheet 516 do not melt due to the gas, the areas of the first external hole H11 and the first intermediate hole H21 are relatively large, and are larger than the area of ​​the first internal hole H31 perpendicular to the X direction when the battery module 10 is operating normally. Therefore, compared to the case where the area of ​​each of the first external hole H11 and the first intermediate hole H21 is relatively small and equal to the area of ​​the first internal hole H31 perpendicular to the X direction during normal operation of the battery module 10, the gas can be efficiently discharged to the outside of the housing 500.

[0051] In this embodiment, compared to the case where the area of ​​the first internal hole H31 is relatively large and equal to the area of ​​the first external hole H11 and the first intermediate hole H21, or the case where the area of ​​the first external hole H11 and the first intermediate hole H21 is relatively small and equal to the area of ​​the first internal hole H31 perpendicular to the X direction during normal operation of the battery module 10, it is possible to achieve both electrical insulation of the battery cell 100 from the outside of the housing 500 and efficient discharge of gas to the outside of the housing 500.

[0052] In this embodiment, the first internal hole H31 and the portion of the first protector 220 between the first first opening 222 from the -Y side and the second first opening 222 from the -Y side overlap each other in the X direction. Therefore, the portion of the first protector 220 between the first first opening 222 from the -Y side and the second first opening 222 from the -Y side forms a partition wall at least partially located between the stack of battery cells 100 and the first internal hole H31. Consequently, compared to the case where the first internal hole H31 and either of the first openings 222 overlap each other in the X direction, exposure of the stack of battery cells 100 to the outside space of the housing 500 through the first internal hole H31 can be reduced during normal operation of the battery module 10, and the battery cells 100 can be electrically insulated from the outside of the housing 500. However, the first internal hole H31 and either of the first openings 222 may overlap each other in the X direction. The partition wall located between the stack of battery cells 100 and the first internal hole H31 may be made of a material different from the first protector 220.

[0053] In this embodiment, the first external hole H11 and the first intermediate hole H21 overlap at least partially in the X direction with the first internal hole H31 and the second first opening 222 from the -Y side. Therefore, the first external hole H11 and the first intermediate hole H21 and the portion of the laminate of the battery cell 100 exposed from the first protector 220 overlap at least partially in the X direction. Consequently, gas can be efficiently discharged to the outside of the housing 500 compared to the case where neither portion of the first external hole H11 nor the first intermediate hole H21 overlaps with either of the first openings 222 in the X direction.

[0054] As with the first external hole H11, the first intermediate hole H21, and the first internal hole H31, the second external hole H12, the second intermediate hole H22, and the second internal hole H32 can achieve both electrical insulation of the battery cell 100 from the outside of the housing 500 and efficient discharge of gas to the outside of the housing 500, compared to when the area of ​​the second internal hole H32 is relatively large and equal to the area of ​​each of the second external hole H12 and the second intermediate hole H22, or when the area of ​​each of the second external hole H12 and the second intermediate hole H22 is relatively small and equal to the area perpendicular to the X direction of the second internal hole H32 during normal operation of the battery module 10. The same is true for the third external hole H13, the third intermediate hole H23, and the third internal hole H33; the fourth external hole H14, the fourth intermediate hole H24, the fourth internal hole H34, and the fifth internal hole H35; the fifth external hole H15, the fifth intermediate hole H25, and the sixth internal hole H36; the sixth external hole H16, the sixth intermediate hole H26, and the seventh internal hole H37; and the seventh external hole H17, the seventh intermediate hole H27, and the eighth internal hole H38.

[0055] Like the first internal hole H31, the second internal hole H32, the third internal hole H33, the fourth internal hole H34, the fifth internal hole H35, the sixth internal hole H36, the seventh internal hole H37, and the eighth internal hole H38 overlap in the X direction with the portion between the first openings 222 of the first protector 220 that are adjacent in the Y direction. Therefore, compared to when these holes overlap with the first openings 222 in the X direction, the stack of battery cells 100 can be more electrically insulated from the outside of the housing 500. In this embodiment, the second internal hole H32 and the sixth internal hole H36 overlap in the X direction with the portion between the third first opening 222 from the -Y side of the first protector 220 and the fourth first opening 222 from the -Y side. The third internal hole H33 overlaps in the X direction with the portion between the fourth first opening 222 from the -Y side of the first protector 220 and the fifth first opening 222 from the -Y side. The fourth internal hole H34 and the seventh internal hole H37 overlap in the X direction with the portion between the seventh first opening 222 from the -Y side and the eighth first opening 222 from the -Y side of the first protector 220. The fifth internal hole H35 and the eighth internal hole H38 overlap in the X direction with the portion between the eighth first opening 222 from the -Y side and the ninth first opening 222 from the -Y side of the first protector 220.

[0056] The second external hole H12 and the second intermediate hole H22, the third external hole H13 and the third intermediate hole H23, and the fourth external hole H14 and the fourth intermediate hole H24 overlap at least partially with different first openings 222 in the X direction, similar to the first external hole H11 and the first intermediate hole H21. Therefore, gas can be efficiently discharged to the outside of the housing 500 compared to the case where these holes do not overlap with the first openings 222 in the X direction. In this embodiment, the second external hole H12 and the second intermediate hole H22 overlap at least partially with the third first opening 222 from the -Y side in the X direction. The third external hole H13 and the third intermediate hole H23 overlap at least partially with the fifth first opening 222 from the -Y side in the X direction. The fourth external hole H14 and the fourth intermediate hole H24 overlap at least partially with the eighth first opening 222 from the -Y side in the X direction.

[0057] In this embodiment, the first external holes H11 to the seventh external holes H17, the first intermediate holes H21 to the seventh intermediate holes H27, and the first internal holes H31 to the eighth internal holes H38 serve as gas discharge sections for discharging gas from the inner space of the housing 500 to the outer space of the housing 500. However, the gas discharge sections are not limited to holes and may also be thin-walled sections. The thickness in the X direction of the thin-walled section is less than the thickness in the X direction of the peripheral portion of the thin-walled section. For example, the metal plate 512 may have partially thinned sections defined instead of the first external holes H11 to the seventh external holes H17. The same applies to the insulating sheet 514 and the insulating heat-resistant sheet 516. Even if the thin-walled section does not penetrate the metal plate 512, insulating sheet 514, or insulating heat-resistant sheet 516 in the X direction, the thin-walled section melts when exposed to a relatively high-temperature gas, forming a hole that penetrates the thin-walled section. Therefore, the thin-walled portion can also function as a gas discharge portion for discharging gas from the inner space of the housing 500 to the outer space of the housing 500. At least one of the metal plate 512, insulating sheet 514, and insulating heat-resistant sheet 516 may define a hole to serve as a gas discharge portion, and at least one other of the metal plate 512, insulating sheet 514, and insulating heat-resistant sheet 516 may define a thin-walled portion to serve as a gas discharge portion.

[0058] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted.

[0059] This application claims priority based on Japanese Patent Application No. 2024-152124, filed September 4, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0060] 10 Battery module, 100 Battery cell, 102 Outer material, 104 Positive electrode tab, 106 Negative electrode tab, 108 Tab group, 110 Compression pad, 200 First voltage detection device, 210 First harness, 220 First protector, 212 First voltage detection terminal, 214 First voltage detection line, 216 First connector, 222 First opening, 300 Second voltage detection device, 310 Second harness, 320 Second protector, 312 Second voltage detection terminal, 314 Second voltage detection line, 316 Second connector, 410 First busbar, 420 Second busbar, 500 Housing, 510 First plate, 512 Metal plate, 514 Insulating sheet, 516 Insulating heat-resistant sheet, 516a First folded part, 516b Second folded part, 520 Second plate, 530 Third plate, 540 Fourth plate, 550 Fifth plate, 560 Sixth plate, H11 First external hole, H12 Second external hole, H13 Third external hole, H14 Fourth external hole, H15 Fifth external hole, H16 Sixth external hole, H17 Seventh external hole, H21 First intermediate hole, H22 Second intermediate hole, H23 Third intermediate hole, H24 Fourth intermediate hole, H25 Fifth intermediate hole, H26 Sixth intermediate hole, H27 Seventh intermediate hole, H31 First internal hole, H32 Second internal hole, H33 Third internal hole, H34 Fourth internal hole, H35 Fifth internal hole, H36 Sixth internal hole, H37 Seventh internal hole, H38 Eighth internal hole

Claims

1. A battery module comprising: a battery cell; and a housing that houses the battery cell, wherein the housing has a first portion that defines a first gas exhaust section, and a second portion that defines a second gas exhaust section that overlaps the first gas exhaust section and has electrical insulation, and wherein the area of ​​the second gas exhaust section is smaller than the area of ​​the first gas exhaust section.

2. The battery module according to claim 1, further comprising a partition wall located at least partially between the battery cell and the second gas exhaust portion.

3. The battery module according to claim 2, wherein the first gas discharge section and the portion of the battery cell exposed from the partition wall at least partially overlap each other.

4. The battery module according to claim 2 or 3, further comprising: a voltage detection unit for detecting the voltage of the battery cell; and a holder for at least partially holding the voltage detection unit, wherein the holder has the partition wall.

5. A battery module according to any one of claims 1 to 4, wherein the second portion is located between the battery cell and the first portion.

6. The battery module according to any one of claims 1 to 5, wherein the first portion includes at least one of a metal and a heat-resistant material.

7. A battery module according to any one of claims 1 to 6, wherein the first gas exhaust section has at least one of a hole penetrating the first part and a thin-walled part of the first part, and the second gas exhaust section has at least one of a hole penetrating the second part and a thin-walled part of the second part.

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