Battery module

Abstract

To control opening / closing of a hole for discharging a gas occurring from battery cells.SOLUTION: A battery module 100 includes: battery cells 110; a plate main portion 152 defining a hole 152a for discharging a gas occurring from the battery cells 110; and a movable cover portion 164 which covers the hole 152a and may open.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

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

[0003] Patent Document 1 describes a battery pack. The battery pack includes a battery having a discharge valve, a case that houses the battery, and a plate member that is provided between the discharge valve and the case.

[0004] Patent Document 2 describes a battery device. The battery device includes a housing portion that houses a battery, and a heat insulating member that is attached to the upper wall of the housing portion and faces the upper surface of the battery. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-197622 [Patent Document 2] Japanese Patent Publication No. 2020-053223 Summary of the Invention [Problem to be solved by the invention]

[0006] A structure such as a housing that houses a battery cell may define a hole for discharging gas generated from the battery cell. When the structure defines the hole, it may be necessary to control the opening and closing of the hole.

[0007] One example of an object of the present invention is to control the opening and closing of holes for discharging gas generated from a battery cell. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0008] One aspect of the present invention is as follows. 1. A battery cell; a structure defining a hole for venting gas generated from the battery cell; an openable covering material covering the hole; A battery module comprising: 2. The battery module according to 1., wherein a plurality of the covering materials cover a plurality of the holes. 3. The battery module according to 2., wherein the plurality of covering materials can be opened independently of each other. 4. A plurality of the battery cells are arranged in a predetermined direction, The battery module according to 2. or 3., wherein the plurality of holes are at least partially aligned in a direction not perpendicular to the predetermined direction. 5. The battery module according to any one of 1. to 4., wherein the covering material is at least partially separable from another covering material that at least partially covers the structure. 6. The battery module according to 5., wherein the covering material and the other covering material are partially connected to each other. 7. The battery module according to any one of 1. to 6., wherein the structure has at least a part of a housing that houses the battery cells. 8. The battery module according to any one of 1. to 7., wherein the covering material has heat resistance. [Effects of the Invention]

[0009] According to the above aspect of the present invention, it is possible to control the opening and closing of the hole for discharging gas generated from the battery cell. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is an exploded perspective view of a battery module according to a first embodiment of the present invention; [Figure 2] FIG. 3 is a top view of a fifth plate and a heat-resistant sheet according to the first embodiment. [Figure 3]3 is a schematic cross-sectional view of the battery module taken along line AA in FIG. 2 in a state in which gas has been generated from some of the battery cells. [Figure 4] 3 is a schematic cross-sectional view of the battery module taken along line BB in FIG. 2 in a state in which gas has been generated from some of the battery cells. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and the description thereof will be omitted as appropriate.

[0012] FIG. 1 is an exploded perspective view of a battery module 100 according to a first embodiment.

[0013] For the purpose of explanation, the X, Y, and Z directions are shown in each figure. The X direction indicates the front-to-rear direction of the battery module 100. The Y direction is perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery module 100. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the up-down direction of the battery module 100. The arrows pointing to the X direction, the Y direction, and the Z direction indicate the front, left, and up directions of the battery module 100, respectively. Hereinafter, as necessary, the tip side of an arrow indicating the X direction will be referred to as the +X side, the opposite side of the tip of the arrow indicating the X direction will be referred to as the -X side, the tip side of an arrow indicating the Y direction will be referred to as the +Y side, the opposite side of the tip of the arrow indicating the Y direction will be referred to as the -Y side, the tip side of an arrow indicating the Z direction will be referred to as the +Z side, and the opposite side of the tip of the arrow indicating the Z direction will be referred to as the -Z side. The relationship between the X direction, Y direction, and Z direction and the front-rear direction, left-right direction, and up-down direction of the battery module 100 is not limited to the above example.

[0014] The battery module 100 will be described with reference to FIG.

[0015] The battery module 100 includes a plurality of battery cells 110 , a plurality of compression pads 120 , a first voltage detection device 130 , a second voltage detection device 140 , a module housing 150 , and a heat-resistant sheet 160 .

[0016] The multiple battery cells 110 are stacked in the Y direction. The multiple battery cells 110 and the multiple compression pads 120 are stacked alternately in the Y direction. Hereinafter, as necessary, the multiple battery cells 110 and the multiple compression pads 120 stacked alternately in the Y direction will be referred to as a stack of battery cells 110. The dimension of each battery cell 110 in the X direction is the dimension in the longitudinal direction of each battery cell 110. The dimension of each battery cell 110 in the Z direction is the dimension in the lateral direction of each battery cell 110. The dimension of each battery cell 110 in the Y direction is the dimension in the thickness direction of each battery cell 110. The shape of each battery cell 110 is not limited to this example.

[0017] Each battery cell 110 includes a battery element (not shown), an exterior material 112, a positive electrode tab 114, and a negative electrode tab 116. In one example, the battery element includes a plurality of positive electrodes and a plurality of negative electrodes (not shown) stacked alternately in the Y direction, and a separator (not shown) positioned between adjacent positive electrodes and negative electrodes in the Y direction. The exterior material 112 seals the battery element and an electrolyte (not shown). The positive electrode tab 114 is electrically connected to the positive electrode of the battery element. The positive electrode tab 114 is drawn out from one of both sides of the exterior material 112 in the X direction. The negative electrode tab 116 is electrically connected to the negative electrode of the battery element. The negative electrode tab 116 is drawn out from the other side of the exterior material 112 in the X direction. However, the structure of each battery cell 110 is not limited to this example.

[0018] Each battery cell 110 may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in the portion corresponding to the separator. An all-solid-state battery does not contain an electrolyte solution. Hereinafter, unless otherwise specified, each battery cell 110 will be described as a battery cell containing an electrolyte solution.

[0019] The multiple battery cells 110 are electrically connected in a combination of series and parallel. Specifically, cell groups including at least two battery cells 110 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 110, a positive electrode tab 114 drawn from a battery cell 110 of one cell group connected in parallel and a negative electrode tab 116 drawn from a battery cell 110 of another cell group connected in parallel are electrically connected to each other, forming a tab group 118 including the positive electrode tab 114 and the negative electrode tab 116. The positive electrode tab 114 and the negative electrode tab 116 in the tab group 118 are joined to each other by, for example, laser welding. A tab group 118 is also located on the -X side of the stack of battery cells 110. Thus, multiple cell groups are connected in series from the cell group located at one end of the stack of battery cells 110 in the Y direction to the cell group located at the other end of the stack of battery cells 110 in the Y direction. Hereinafter, as necessary, the tab group 118 located on the +X side of the stack of battery cells 110 will be referred to as the +X side tab group 118, and the tab group 118 located on the -X side of the stack of battery cells 110 will be referred to as the -X side tab group 118.

[0020] The electrical connection of the plurality of battery cells 110 is not limited to the above example. For example, a stack of battery cells 110 may be formed by connecting single battery cells 110 in series.

[0021] The first voltage detection device 130 detects the voltages of the multiple +X side tab groups 118. The first voltage detection device 130 includes a first protector 131, multiple first voltage detection terminals 132, multiple first voltage detection lines 133, a first connector 134, and a first bus bar 135.

[0022] The first protector 131 covers the +X side portion of the stack of battery cells 110. The first protector 131 is made of an insulating material such as resin. The first protector 131 defines a plurality of first openings 131a. Each of the plurality of +X side tab groups 118 is exposed toward the +X side through each of the plurality of first openings 131a.

[0023] Each of the multiple first voltage detection terminals 132 is located on the +X side of each of the multiple +X side tab groups 118. Each first voltage detection terminal 132 is made of a conductor such as metal. The -X side surface of each first voltage detection terminal 132 and the +X side surface of each +X side tab group 118 are joined to each other by a joining method such as laser welding. Therefore, each first voltage detection terminal 132 and each +X side tab group 118 are electrically connected to each other. Therefore, the first voltage detection device 130 can detect the voltage of each +X side tab group 118 using each first voltage detection terminal 132. The multiple first voltage detection terminals 132 are held together by a first protector 131. Therefore, by installing the first protector 131 at an appropriate position relative to the stack of battery cells 110, each of the multiple first voltage detection terminals 132 can be positioned appropriately relative to each of the multiple +X side tab groups 118.

[0024] One end of each first voltage detection line 133 is electrically connected to each first voltage detection terminal 132. The other end of each first voltage detection line 133 is electrically connected to each first connector 134. Therefore, the multiple first voltage detection terminals 132 and the first connector 134 are electrically connected to each other via the multiple first voltage detection lines 133. Each first voltage detection line 133 is routed between one end of the first voltage detection line 133 and the other end of the first voltage detection line 133 via the first protector 131.

[0025] The first bus bar 135 is disposed at the end of the first protector 131 on the +Y side. The first bus bar 135 is electrically connected to the positive electrode tab 114 drawn out to the +X side from the battery cell 110 of the cell group located at the end of the +Y side of the stack of battery cells 110. The first bus bar 135 functions as an external terminal for electrically connecting the battery module 100 to an external device such as another battery module.

[0026] The second voltage detecting device 140 detects the voltages of the plurality of -X side tab groups 118. The second voltage detecting device 140 includes a second protector 141, a plurality of second voltage detecting terminals 142, a plurality of second voltage detecting lines 143, a second connector 144, and a second bus bar 145.

[0027] The second protector 141 covers the -X side portion of the stack of battery cells 110. The second protector 141 is made of an insulating material such as resin. The second protector 141 defines a plurality of second openings 141a. Each of the plurality of -X side tab groups 118 is exposed toward the -X side through each of the plurality of second openings 141a.

[0028] Each of the multiple second voltage detection terminals 142 is located on the -X side of each of the multiple -X side tab groups 118. Each second voltage detection terminal 142 is made of a conductor such as metal. The +X side surface of each second voltage detection terminal 142 and the -X side surface of each -X side tab group 118 are joined to each other by a joining method such as laser welding. Therefore, each second voltage detection terminal 142 and each -X side tab group 118 are electrically connected to each other. Therefore, the second voltage detection device 140 can detect the voltage of each -X side tab group 118 using each second voltage detection terminal 142. The multiple second voltage detection terminals 142 are held together by a second protector 141. Therefore, by installing the second protector 141 at an appropriate position relative to the stack of battery cells 110, each of the multiple second voltage detection terminals 142 can be positioned appropriately relative to each of the multiple -X side tab groups 118.

[0029] One end of each second voltage detection line 143 is electrically connected to each second voltage detection terminal 142. The other end of each second voltage detection line 143 is electrically connected to each second connector 144. Therefore, the second voltage detection terminals 142 and the second connector 144 are electrically connected to each other via the second voltage detection lines 143. Each second voltage detection line 143 is routed between one end of the second voltage detection line 143 and the other end of the second voltage detection line 143 via the second protector 141.

[0030] The second bus bar 145 is disposed at the -Y side end of the second protector 141. The second bus bar 145 is electrically connected to the negative electrode tab 116 drawn out to the -X side from the battery cell 110 of the cell group located at the -Y side end of the stack of battery cells 110. The second bus bar 145 functions as an external terminal for electrically connecting the battery module 100 to an external device such as another battery module.

[0031] 1 , the positive electrode tab 114 at the end of a group of multiple cells connected in series is drawn out toward the +X side from the battery cell 110 of the cell group located at the end on the +Y side of the stack of battery cells 110, and the negative electrode tab 116 at the end of a group of multiple cells connected in series is drawn out toward the -X side from the battery cell 110 of the cell group located at the end on the -Y side of the stack of battery cells 110. Thus, the first bus bar 135 is disposed on the +X side and the +Y side of the stack of battery cells 110, and the second bus bar 145 is disposed on the -X side and the -Y side of the stack of battery cells 110. However, the arrangement of the positive electrode tab 114 and the negative electrode tab 116 at the end of a group of multiple cells connected in series may differ depending on the number of battery cells 110 included in the stack of battery cells 110. For example, there are cases where the positive electrode tab 114 at the end of a group of multiple cells connected in series is pulled out toward the +X side from the battery cell 110 of the cell group located at the end on the +Y side of the stack of battery cells 110, and the negative electrode tab 116 at the end of a group of multiple cells connected in series is pulled out toward the +X side from the battery cell 110 of the cell group located at the end on the -Y side of the stack of battery cells 110. In this case, the bus bar electrically connected to the positive electrode tab 114 at the end of the group of multiple cells connected in series is arranged on both the +X side and the +Y side of the stack of battery cells 110, and the bus bar electrically connected to the negative electrode tab 116 at the end of the group of multiple cells connected in series is arranged on the +X side and the -Y side of the stack of battery cells 110.

[0032] The module housing 150 houses a stack of battery cells 110. The module housing 150 includes a first plate 150a, a second plate 150b, a third plate 150c, a fourth plate 150d, a fifth plate 150e, and a sixth plate 150f. Each plate is a metal plate such as an aluminum plate.

[0033] The first plate 150a covers the +X side portion of the stack of battery cells 110, with the first voltage detection device 130 positioned between the stack of battery cells 110 and the first plate 150a.

[0034] The second plate 150b covers the −X side of the stack of battery cells 110, with the second voltage detection device 140 positioned between the stack of battery cells 110 and the second plate 150b.

[0035] The third plate 150c covers the +Y side portion of the stack of battery cells 110.

[0036] The fourth plate 150d covers the −Y side portion of the stack of battery cells 110.

[0037] The fifth plate 150e includes a plate main body portion 152 and multiple drawn-out portions 154. The plate main body portion 152 has a plate shape perpendicular to the Z direction. In the example shown in FIG. 1, when viewed from the Z direction, the plate main body portion 152 has a substantially rectangular shape having a pair of sides extending in the X direction and another pair of sides extending in the Y direction. The shape of the plate main body portion 152 is not limited to the example shown in FIG. 1. The multiple drawn-out portions 154 are drawn out from both sides of the plate main body portion 152 in the X direction. When viewed from the Y direction, the +X-side drawn-out portion 154 has a substantially L-shape including a portion bent from the +X-side side of the plate main body portion 152 toward the -Z side and another portion bent from the -Z-side end of the bent portion toward the +X side. When viewed from the Y direction, the -X side drawn-out portion 154 has a substantially L-shape that includes a portion bent from the -X side edge of the plate main body portion 152 toward the -Z side and another portion bent from the -Z side end of the bent portion toward the -X side. The shape of each drawn-out portion 154 is not limited to the example shown in FIG. 1.

[0038] The fifth plate 150e covers a portion of the stack of battery cells 110 on the +Z side, with a plurality of structural adhesives 172 positioned between the stack of battery cells 110 and the fifth plate 150e. In the example shown in FIG. 1 , the plurality of structural adhesives 172 extend in the Y direction. The number and arrangement of the structural adhesives 172 are not limited to the example shown in FIG. 1 . The stack of battery cells 110 and the fifth plate 150e are bonded to each other via the plurality of structural adhesives 172.

[0039] The sixth plate 150f covers the -Z side portion of the stack of battery cells 110, with the thermally conductive adhesive 174 located between the stack of battery cells 110 and the sixth plate 150f. The stack of battery cells 110 and the sixth plate 150f are bonded to each other via the thermally conductive adhesive 174. The stack of battery cells 110 and the sixth plate 150f are thermally coupled to each other via the thermally conductive adhesive 174.

[0040] Fig. 2 is a top view of the fifth plate 150e and the heat-resistant sheet 160 according to the first embodiment. Fig. 3 is a schematic cross-sectional view of the battery module 100 taken along line AA in Fig. 2 in a state in which gas G has been generated from some of the battery cells 110. Fig. 4 is a schematic cross-sectional view of the battery module 100 taken along line BB in Fig. 2 in a state in which gas G has been generated from some of the battery cells 110. Figs. 3 and 4 show a cross-section of the battery module 100 in a state in which the fifth plate 150e and the heat-resistant sheet 160 shown in Fig. 2 have been assembled. For ease of explanation, the structural adhesive 172 and the thermally conductive adhesive 174 shown in Fig. 1 are not shown in Figs. 3 and 4.

[0041] In Fig. 2, the white circle with a black dot indicating the Z direction indicates that the tip of the arrow indicating the Z direction is pointing towards the front of the page. In Fig. 3, the white circle with a black dot indicating the Y direction indicates that the tip of the arrow indicating the Y direction is pointing towards the front of the page. In Fig. 4, the white circle with an X indicating the X direction indicates that the tip of the arrow indicating the X direction is pointing towards the back of the page.

[0042] For the sake of explanation, Fig. 3 shows a pack housing 200 that houses the battery module 100. As shown in Fig. 3, the pack housing 200 has a lower plate 210 that covers the -Z side surface of the battery module 100, and an upper plate 220 that covers the +Z side surface of the battery module 100. The lower plate 210 and the upper plate 220 are made of a metal such as aluminum.

[0043] A method for discharging gas G generated from some of the battery cells 110 from the module housing 150 will be described with reference to FIGS.

[0044] As shown in FIGS. 3 and 4 , high-temperature gas G may be generated from the battery cell 110 when abnormal heat generation occurs in the battery cell 110. Abnormal heat generation in the battery cell 110 occurs, for example, when electrodes such as the positive and negative electrodes of the battery cell 110 are short-circuited due to factors such as vibration of the battery module 100 or an impact on the battery module 100. Abnormal heat generation in the battery cell 110 is likely to occur in the approximately central portion in the X and Y directions of the stack of battery cells 110. This is because the approximately central portion in the X and Y directions of the stack of battery cells 110 is more susceptible to the effects of heat than the peripheral areas of the approximately central portion in the X and Y directions of the stack of battery cells 110. Therefore, gas G generated from the battery cell 110 when abnormal heat generation occurs in the battery cell 110 is likely to occur in the approximately central portion in the X and Y directions of the stack of battery cells 110.

[0045] 1 and 2, the plate main body portion 152 has a structure that defines a plurality of holes 152a for discharging the gas G. Each hole 152a penetrates the plate main body portion 152 in the Z direction. The number of holes 152a is not limited to the example shown in FIGS. 1 and 2, and may be, for example, only one.

[0046] 1 and 2, the multiple holes 152a are located in approximately the center in the X direction of the plate main body portion 152 when viewed from the Z direction. As described above, gas G is likely to be generated in approximately the center in the X and Y directions of the stack of battery cells 110. Therefore, compared to when the multiple holes 152a are located offset in the X direction from the approximately center in the X direction of the plate main body portion 152, it is possible to more easily discharge the gas G from the module housing 150 through each hole 152a. However, the multiple holes 152a may also be located offset in the X direction from the approximately center in the X direction of the plate main body portion 152.

[0047] In the example shown in FIGS. 1 and 2, the multiple holes 152a are aligned in the Y direction. As described above, the multiple battery cells 110 are aligned in the Y direction. Therefore, compared to when the multiple holes 152a are aligned in the X direction, it is easier to arrange any one of the holes 152a relatively close to a larger number of battery cells 110, and it is easier to discharge gas G regardless of which battery cell 110 generates gas G. Therefore, when viewed from the Z direction, it is preferable that the multiple holes 152a are aligned in a direction that is at least partially non-perpendicular to the Y direction. However, the multiple holes 152a may also be aligned in the X direction. Alternatively, the multiple holes 152a may be aligned in multiple rows in the Y direction.

[0048] 1 and 2, when viewed from the Z direction, the holes 152a other than the holes 152a located at both ends in the Y direction have a substantially circular shape. In the example shown in Figures 1 and 2, when viewed from the Z direction, the holes 152a located at both ends in the Y direction have a shape that combines a substantially quadrangle having a pair of sides extending in the X direction and another pair of sides extending in the Y direction with a substantially semicircular shape protruding from both sides in the X direction of the quadrangle. However, the shape of each hole 152a is not limited to the example shown in Figures 1 and 2.

[0049] 1 and 2, the heat-resistant sheet 160 is located on the +Z side of the +Z side surface of the approximate center in the X direction of the plate main body portion 152. As shown in FIGS. 1 and 2, the heat-resistant sheet 160 includes a fixed covering portion 162 and a plurality of movable covering portions 164.

[0050] In the example shown in FIGS. 1 and 2 , the fixed covering portion 162 is a covering material that covers the +Z side surface of the approximately central portion in the X direction of the plate body portion 152 around the multiple holes 152a. Around the multiple holes 152a, the -Z side surface of the fixed covering portion 162 and the +Z side surface of the approximately central portion in the X direction of the plate body portion 152 are bonded to each other. In the example shown in FIGS. 1 and 2 , the fixed covering portion 162 is not provided on both sides of the approximately central portion in the X direction of the plate body portion 152, but is selectively provided in the approximately central portion in the X direction of the plate body portion 152. Therefore, the amount and cost of the heat-resistant sheet 160 can be reduced compared to when the fixed covering portion 162 is provided over the entire +Z side surface of the plate body portion 152. Portions of the plate body portion 152 that are relatively far from the holes 152a in the direction perpendicular to the Z direction are less susceptible to the effects of the gas G, regardless of the presence or absence of the heat-resistant sheet 160. Therefore, even if the fixed covering portion 162 is selectively provided in approximately the center portion in the X direction of the plate main body portion 152, the portion of the plate main body portion 152 that is not covered by the heat-resistant sheet 160 can be made less susceptible to the effects of the gas G. The shape of the fixed covering portion 162 is not limited to the example shown in Figures 1 and 2. For example, the fixed covering portion 162 may cover the entire surface of the plate main body portion 152 on the +Z side.

[0051] In the embodiment, each movable covering portion 164 is an openable covering material that covers the opening on the +Z side of each hole 152 a. Therefore, the opening of the movable covering portion 164 can control the opening and closing of the opening on the +Z side of each hole 152 a.

[0052] Specifically, during normal operation of the battery cell 110, the -Z side surface of the movable cover portion 164 and the Z-direction surrounding portions of the holes 152a on the +Z side surface of the plate main portion 152 are bonded to each other. Therefore, during normal operation of the battery cell 110, the +Z side opening of each hole 152a can be closed by the movable cover portion 164. In the embodiment, an insulator (not shown) is provided on the -Z side surface of the plate main portion 152 to prevent short-circuiting between the battery cell 110 and the plate main portion 152. The insulator is, for example, an insulating sheet such as a PET (polyethylene terephthalate) sheet attached to substantially the entire -Z side surface of the plate main portion 152. During normal operation of the battery cell 110, the insulator covers and closes the -Z side opening of each hole 152a. For example, when the -Z side surface of the plate main body portion 152 and the +Z side surface of the insulator are bonded to each other via an adhesive and the insulator is flexible, the portion of the insulator that overlaps with the hole 152a in the Z direction and the portion of the insulator that enters the hole 152a may be bonded to each other, with the portion overlapping with the hole 152a in the Z direction being bent toward the hole 152a. Alternatively, when both the movable covering portion 164 and the insulator are flexible, the portion of the movable covering portion 164 that enters the hole 152a and the portion of the insulator that enters the hole 152a may be bonded to each other, with the portion of the movable covering portion 164 that enters the hole 152a in the Z direction and the portion of the insulator that enters the hole 152a being bent toward the hole 152a.

[0053] 3 and 4, when abnormal heat generation occurs in the battery cell 110, the insulator melts due to the heat of the gas G or breaks due to the pressure of the gas G. Therefore, when abnormal heat generation occurs in the battery cell 110, the opening on the -Z side of each hole 152a is opened from the insulator, and the gas G passes through the hole 152a. When abnormal heat generation occurs in the battery cell 110, the movable cover part 164 that overlaps in the Z direction with the hole 152a through which the gas G passes is peeled off from the +Z side surface of the plate main body part 152 due to factors such as the pressure and heat of the gas G. Therefore, when abnormal heat generation occurs in the battery cell 110, the opening on the +Z side of the hole 152a through which the gas G passed can be opened by the opening of the movable cover part 164. Therefore, the gas G can be discharged from the module housing 150 through the hole 152a.

[0054] The insulators described above may not be provided, or may define holes communicating with the holes 152a during normal operation of the battery cell 110.

[0055] In the embodiment, the multiple movable covering portions 164 are capable of opening independently of one another. Therefore, as shown in FIG. 4, even if gas G is generated from some of the battery cells 110, the movable covering portions 164 that overlap in the Z direction with the holes 152a through which little or no gas G passes are not opened. This prevents the gas G discharged from the module housing 150 through the holes 152a through which gas G passes from flowing back through the holes 152a through which little or no gas G passes. However, the covering of the holes 152a by the movable covering portions 164 is not limited to the example described in the embodiment. For example, one movable covering portion 164 may cover multiple holes 152a.

[0056] 1 and 2, the multiple movable covering portions 164 are at least partially separable from the fixed covering portion 162 by slits 164a formed at least partially around each movable covering portion 164 in the Z direction. Therefore, by forming the slits 164a in the heat-resistant sheet 160, the movable covering portions 164 can be formed relatively easily. The method of forming the movable covering portions 164 is not limited to the method of forming the slits 164a in the heat-resistant sheet 160. For example, the movable covering portion 164 may be openable by a mechanical element such as a hinge.

[0057] 1 and 2, each movable covering portion 164 other than the movable covering portions 164 located at both ends in the Y direction can be separated from the movable covering portion 164 by slits 164a located around the movable covering portion 164 in the Z direction, except for the portion on the -X side of each movable covering portion 164. In the example shown in FIGS. 1 and 2, when viewed from the Z direction, the slits 164a extend along a pair of sides extending in the X direction on both sides of each movable covering portion 164 in the Y direction, and along a side extending in the Y direction on the +X side of the movable covering portion 164. Each movable covering portion 164 and the fixed covering portion 162 are partially connected to each other at locations where there are no slits 164a around each movable covering portion 164 in the Z direction. Therefore, each movable covering portion 164 can be opened in a direction perpendicular to the Z direction, except for the portion where the movable covering portion 164 and the fixed covering portion 162 are connected to each other. Therefore, when each movable covering portion 164 is opened, the gas G can be discharged mainly toward the +X side, as shown in Fig. 3. Furthermore, as shown in Fig. 3, at least a portion of the opened movable covering portion 164 can be positioned between the hole 152a and the upper plate 220, which can prevent damage to the upper plate 220 caused by the gas G being directly injected onto the upper plate 220.

[0058] 1 and 2, the movable covering part 164 located at one end on the +Y side can be separated from the movable covering part 164 by a slit 164a located around the movable covering part 164 in the Z direction, excluding the -X side and +Y side portions of the movable covering part 164. In the example shown in FIGS. 1 and 2, when viewed from the Z direction, the slit 164a extends along an edge extending in the X direction on the -Y side of the movable covering part 164 and an edge extending in the Y direction on the +X side of the movable covering part 164. The movable covering part 164 and the fixed covering part 162 are connected to each other at locations where the slit 164a does not exist around the movable covering part 164 in the Z direction. Therefore, the movable covering part 164 can be opened in a direction perpendicular to the Z direction, excluding the location where the movable covering part 164 and the fixed covering part 162 are connected to each other. Therefore, when the movable covering part 164 is opened, the gas G can be discharged mainly toward the +X side while suppressing the discharge of the gas G toward the +Y side. Furthermore, similar to the example shown in Fig. 3, at least a portion of the opened movable covering part 164 can be positioned between the hole 152a and the upper plate 220, and damage to the upper plate 220 caused by the gas G being directly injected onto the upper plate 220 can be suppressed.

[0059] In the example shown in Figures 1 and 2, the movable covering part 164 located at the other end on the -Y side can be made similar to the movable covering part 164 located at one end on the +Y side, except that the movable covering part 164 located at one end on the +Y side and the movable covering part 164 located at one end on the -Y side are approximately symmetrical.

[0060] The opening direction of each movable covering portion 164 is not limited to the example shown in FIGS. 1 and 2. The opening direction of each movable covering portion 164 can be varied depending on the direction of discharge of gas G. The direction of discharge of gas G is determined depending on predetermined conditions such as the location and use of the battery module 100. In the embodiment, the opening direction of each movable covering portion 164 can be controlled depending on the position of the slit 164a around the Z direction of each movable covering portion 164. Therefore, by forming the slit 164a at an appropriate position around the Z direction of each movable covering portion 164 depending on the desired direction of discharge of gas G, the opening direction of each movable covering portion 164 can be controlled.

[0061] The material of the heat-resistant sheet 160 is not particularly limited as long as it can protect components such as the upper plate 220 located on the +Z side of the battery module 100 from the gas discharged through the holes 152a. The heat-resistant sheet 160 is, for example, a fiber sheet made of silicone fibers. Alternatively, the heat-resistant sheet 160 can be, but is not limited to, a fiber sheet made of fibers containing carbon, silica, alumina, magnesia, or the like, sheeted together with a silicone resin or a fluorine-based resin, or a ceramic plate. From the viewpoints of formability and heat resistance, the above-mentioned fiber sheets having fibers with a heat resistance temperature of 1000°C or higher are particularly preferred. However, the covering material covering the holes 152a does not have to be heat-resistant.

[0062] 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.

[0063] For example, in the embodiment, the plate body portion 152 has a structure that defines holes for discharging gas G generated from the battery cells 110. However, the structure described using the embodiment can also be applied to a member different from the plate body portion 152 of the module housing 150 or a member different from the module housing 150. [Explanation of symbols]

[0064] 100 battery module, 110 battery cell, 112 exterior material, 114 positive electrode tab, 116 negative electrode tab, 118 tab group, 120 compression pad, 130 first voltage detection device, 131 first protector, 131a first opening, 132 first voltage detection terminal, 133 first voltage detection line, 134 first connector, 135 first bus bar, 140 second voltage detection device, 141 second protector, 141a second opening, 142 second voltage detection terminal, 143 second voltage detection line, 144 second connector, 145 second bus bar, 150 module housing, 150a first plate, 150b second plate, 150c third plate, 150d fourth plate, 150e fifth plate, 150f sixth plate, 152 plate main body portion, 152a hole, 154 Drawer portion, 160 heat-resistant sheet, 162 fixed covering portion, 164 movable covering portion, 164a slit, 172 structural adhesive, 174 thermally conductive adhesive, 200 pack housing, 210 lower plate, 220 upper plate, G gas

Claims

1. A battery cell; a structure defining a hole for venting gas generated from the battery cell; an openable covering material covering the hole; A battery module comprising:

2. The battery module according to claim 1 , wherein a plurality of the covering materials cover a plurality of the holes.

3. The battery module according to claim 2 , wherein the plurality of covering materials are capable of being opened independently of one another.

4. A plurality of the battery cells are arranged in a predetermined direction, The battery module according to claim 2 or 3, wherein the plurality of holes are at least partially aligned in a direction not perpendicular to the predetermined direction.

5. 4. The battery module according to claim 1, wherein the covering material is at least partially separable from another covering material that at least partially covers the structure.

6. The battery module according to claim 5 , wherein the covering material and the other covering material are partially connected to each other.

7. The battery module according to any one of claims 1 to 3, wherein the structure has at least a part of a housing that houses the battery cells.

8. The battery module according to any one of claims 1 to 3, wherein the covering material has heat resistance.

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