Battery module

Abstract

To remove a battery cell with abnormality generation from other battery cells.SOLUTION: The battery module 100 includes a plurality of battery cells 110 and a thermally expandable material 300 located at least partially between the plurality of battery cells 110. The thermally expandable material 300 at least partially surrounds at least a portion of the region between the plurality of battery cells 110.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, various battery modules have been developed, each of which includes a plurality of battery cells.

[0003] Patent Document 1 describes a battery module. The battery module includes a plurality of batteries and a thermal expansion member. The thermal expansion member is interposed between the wide surfaces of the plurality of batteries.

[0004] Patent Document 2 describes a battery module. The battery module includes a plurality of battery cells, an elastic member positioned between adjacent battery cells, and a thermally expandable resin composition disposed on the elastic member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-169135 [Patent Document 2] Japanese Patent Publication No. 2022-187202 Summary of the Invention [Problem to be solved by the invention]

[0006] A battery cell in which an abnormality has occurred may generate relatively high-temperature gas, and therefore it may be necessary to isolate the battery cell in which an abnormality has occurred from the other battery cells.

[0007] One example of an object of the present invention is to isolate a battery cell in which an abnormality has occurred from other battery cells. 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 plurality of battery cells; a thermal expansion material at least partially positioned between the plurality of battery cells; Equipped with The thermal expansion material at least partially surrounds at least a portion of an area existing between the plurality of battery cells. 2. The battery module described in 1., wherein at least a portion of the region overlaps with a central portion of the battery cell. 3. The battery module according to 1. or 2., further comprising a compression pad at least partially positioned in at least said portion of said area. 4. The battery module according to any one of 1. to 3., wherein the thermal expansion material at least partially contains a foam material. [Effects of the Invention]

[0009] According to the above aspect of the present invention, a battery cell in which an abnormality has occurred can be isolated from other battery cells. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is an exploded top perspective view of the battery module according to the embodiment. [Figure 2] FIG. 2 is a front view of the battery module according to the embodiment. [Figure 3] FIG. 10 is a front view of the battery module according to the embodiment in a state where an abnormality has occurred in 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 an embodiment.

[0013] For the sake of explanation, the X, Y, and Z directions are shown in FIG. 1 and FIG. 2, which will be described later. 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. An arrow pointing to the X direction, an arrow pointing to the Y direction, and an arrow pointing to 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 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, and a housing 200.

[0015] 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. In the example shown in FIG. 1, when viewed from the Y direction, each compression pad 120 has a substantially rectangular shape having a pair of long sides extending in the X direction and a pair of short sides extending in the Z direction. The shape of each compression pad 120 is not limited to the example shown in FIG. 1.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] The first voltage detecting device 130 detects the voltages of the plurality of +X side tab groups 118. The first voltage detecting device 130 has a first protector 131, a plurality of first voltage detecting terminals 132, a plurality of first voltage detecting lines 133, a first connector 134, and a first bus bar 135.

[0021] 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.

[0022] 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 conductive material 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.

[0023] 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.

[0024] The first bus bar 135 is disposed at the end portion on the +Y side of the first protector 131. 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 portion on 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.

[0025] The second voltage detecting device 140 detects the voltages of the plurality of -X side tab groups 118. The second voltage detecting device 140 has 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.

[0026] 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.

[0027] 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 conductive material 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.

[0028] 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.

[0029] The second bus bar 145 is disposed at the end portion on the -Y side 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 end portion on the -Y side 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.

[0030] 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 portion 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 portion 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 may be cases where 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 portion 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 portion on the -Y side of the stack of battery cells 110. In this case, the first bus bar 135 is arranged on the +X side and the +Y side of the stack of battery cells 110, and the second bus bar 145 is arranged on the +X side and the -Y side of the stack of battery cells 110.

[0031] The housing 200 has a first plate 210, a second plate 220, a third plate 230, a fourth plate 240, a fifth plate 250, and a sixth plate 260.

[0032] The first plate 210 covers the +X side portion of the stack of battery cells 110, with the first voltage detection device 130 located between the stack of battery cells 110 and the first plate 210. The second plate 220 covers the -X side portion of the stack of battery cells 110, with the second voltage detection device 140 located between the stack of battery cells 110 and the second plate 220. The third plate 230 covers the +Y side portion of the stack of battery cells 110. The fourth plate 240 covers the -Y side portion of the stack of battery cells 110. The fifth plate 250 covers the +Z side portion of the stack of battery cells 110, with multiple structural adhesives 252 located between the stack of battery cells 110 and the fifth plate 250. In the example shown in FIG. 1 , the multiple structural adhesives 252 extend in the Y direction. The arrangement of the structural adhesives 252 is not limited to the example shown in FIG. 1 . The stack of battery cells 110 and the fifth plate 250 are bonded to each other via a plurality of structural adhesives 252. The sixth plate 260 covers the -Z side portion of the stack of battery cells 110, with the thermally conductive adhesive 262 positioned between the stack of battery cells 110 and the sixth plate 260. The stack of battery cells 110 and the sixth plate 260 are bonded to each other via the thermally conductive adhesive 262. The stack of battery cells 110 and the sixth plate 260 are thermally coupled to each other via the thermally conductive adhesive 262. The thermal conductivity of the thermally conductive adhesive 262 is higher than the thermal conductivity of each structural adhesive 252. Therefore, heat generated from the stack of battery cells 110 can be more easily conducted to the thermally conductive adhesive 262 than to the structural adhesive 252.

[0033] Fig. 2 is a schematic front view of the battery module 100 according to the embodiment. Fig. 3 is a schematic front view of the battery module 100 according to the embodiment in a state in which an abnormality has occurred in some of the battery cells 110. For the sake of explanation, the +X side tab group 118, the first voltage detection device 130, the first plate 210, the structural adhesive 252, and the thermally conductive adhesive 262 have been removed from Figs. 2 and 3 .

[0034] A battery module 100 according to an embodiment will be described with reference to FIGS.

[0035] As shown in FIGS. 1 and 2 , a thermal expansion material 300 is located between adjacent battery cells 110 in the Y direction. Each thermal expansion material 300 has electrical insulation properties. As shown in FIG. 1 , when viewed from the Y direction, each thermal expansion material 300 at least partially surrounds, in the Y direction, at least a portion of the area between adjacent battery cells 110 in the Y direction. In the example shown in FIG. 1 , each thermal expansion material 300 at least partially surrounds, in the Y direction, at least a portion of a compression pad 120 located between adjacent battery modules 100 in the Y direction. Each thermal expansion material 300 and each compression pad 120 may be attached to each other or may be separate. The inner peripheral portion of each thermal expansion material 300 around the Y direction and the outer peripheral portion of each compression pad 120 around the Y direction may be offset from each other in a direction perpendicular to the Y direction, or may at least partially overlap each other in the Y direction.

[0036] 1 , when viewed from the Y direction, each thermal expansion material 300 extends along three sides, the +X side, the -X side, and the +Z side, of each compression pad 120, with each compression pad 120 overlapping in the Y direction with the center portion of each battery cell 110 in the direction perpendicular to the Y direction. Hereinafter, the first thermal expansion portion 302 refers to the portion of each thermal expansion material 300 extending along the +X side side of each compression pad 120, the second thermal expansion portion 304 refers to the portion of each thermal expansion material 300 extending along the -X side side of each compression pad 120, and the third thermal expansion portion 306 refers to the portion of each thermal expansion material 300 extending along the +Z side side of each compression pad 120. The shape of each thermal expansion material 300 is not limited to the example shown in FIG. 1 .

[0037] The thermal expansion of the thermal expansion material 300 according to the embodiment will be described with reference to Figures 1 to 3. In the example shown in Figure 3, an abnormal battery cell 110a refers to a battery cell 110 in which an abnormality has occurred.

[0038] Relatively high-temperature gas may be generated from the abnormal battery cell 110a. When gas is generated from the abnormal battery cell 110a, the gas generated from the abnormal battery cell 110a causes the +X-side end of the first thermal expansion portion 302, the -X-side end of the second thermal expansion portion 304, and the +Z-side end of the third thermal expansion portion 306 of each of the thermal expansion materials 300 located on both sides of the abnormal battery cell 110a in the Y direction to thermally expand toward the +X side, the -X side, and the +Z side, respectively.

[0039] Due to the thermal expansion of the +X side end of the first thermal expansion portion 302 toward the +X side, the +X side end of the first thermal expansion portion 302 at least partially contacts at least one of the first voltage detection device 130 and the first plate 210. Therefore, in a state in which the +X side end of the first thermal expansion portion 302 is thermally expanded toward the +X side, the first thermal expansion portion 302 functions as a partition member that at least partially separates the space present on the +X side relative to the abnormal battery cell 110a and the space present on the +X side relative to the other battery cells 110 from each other.

[0040] Due to the thermal expansion of the -X side end of the second thermal expansion portion 304 toward the -X side, the -X side end of the second thermal expansion portion 304 at least partially contacts at least one of the second voltage detection device 140 and the second plate 220. Therefore, in a state in which the -X side end of the second thermal expansion portion 304 is thermally expanded toward the -X side, the second thermal expansion portion 304 functions as a partition member that at least partially separates the space present on the -X side relative to the abnormal battery cell 110a and the space present on the -X side relative to the other battery cells 110 from each other.

[0041] 3, due to thermal expansion of the +Z side end of the third thermal expansion portion 306 toward the +Z side, the +Z side end of the third thermal expansion portion 306 at least partially contacts at least one of the fifth plate 250 and the structural adhesive 252. Therefore, with the +Z side end of the third thermal expansion portion 306 thermally expanded toward the +Z side, the third thermal expansion portion 306 functions as a partition member that at least partially separates the space present on the +Z side of the abnormal battery cell 110a and the space present on the +Z side of the other battery cells 110 from each other.

[0042] 1, the thermal expansion material 300 is not provided along the -Z side edge of the compression pad 120. In the example shown in FIG. 1, the -Z side surface of the abnormal battery cell 110a and the +Z side surface of the thermally conductive adhesive 262 are in contact with each other. Therefore, even if the thermal expansion material 300 does not thermally expand toward the -Z side, the abnormal battery cell 110a and the other battery cells 110 can be separated from each other between the stack of battery cells 110 and the thermally conductive adhesive 262. However, the thermal expansion material 300 may also have a portion that extends along the -Z side edge of the compression pad 120.

[0043] With the thermal expansion material 300 functioning as a partition member that at least partially separates the space around the abnormal battery cell 110a in the Y direction from the space around the other battery cells 110 in the Y direction, the abnormal battery cell 110a and the other battery cells 110 are physically isolated from each other. This makes it possible to prevent high-temperature gas generated from the abnormal battery cell 110a from spreading to the surroundings of the other battery cells 110. This makes it possible to prevent the occurrence of abnormalities in the other battery cells 110 due to the propagation of high-temperature gas generated from the abnormal battery cell 110a to the other battery cells 110.

[0044] When the thermal expansion material 300 is thermally expanded to at least partially separate the space around the abnormal battery cell 110a in the Y direction from the space around the other battery cells 110 in the Y direction, the thermal expansion material 300 does not need to overlap the center and its peripheral portion of the battery cell 110 in the Y direction perpendicular to the Y direction. Therefore, compared to when the thermal expansion material 300 and the entire surface of the battery cell 110 perpendicular to the Y direction overlap each other in the Y direction, the compressive load due to the thermal expansion of the thermal expansion material 300 on battery cells 110 other than the abnormal battery cell 110a can be suppressed. This makes it easier to suppress a chain reaction of abnormalities to battery cells 110 other than the abnormal battery cell 110a. Furthermore, compared to when the thermal expansion material 300 and the entire surface of the battery cell 110 perpendicular to the Y direction overlap each other in the Y direction, the dimension of the stack of battery cells 110 in the Y direction can be reduced.

[0045] In the embodiment, the thermal expansion material 300 at least partially contains a foam material such as foam rubber. Therefore, even if the thermal expansion material 300 is heated by gas generated from the abnormal battery cell 110a, the thermal expansion material 300 is more likely to foam than to melt. Therefore, in the embodiment, even if the thermal expansion material 300 is heated by gas generated from the abnormal battery cell 110a, the electrical insulation of the thermal expansion material 300 can be more easily ensured than if the thermal expansion material 300 were to melt. However, the thermal expansion material 300 may be a thermal expansion material other than a foam material.

[0046] 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. [Explanation of symbols]

[0047] 100 battery module, 110 battery cell, 110a abnormal 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, 200 housing, 210 first plate, 220 second plate, 230 third plate, 240 fourth plate, 250 fifth plate, 252 structural adhesive, 260 sixth plate, 262 Thermally conductive adhesive, 300 thermal expansion material, 302 first thermal expansion portion, 304 second thermal expansion portion, 306 third thermal expansion portion

Claims

1. A plurality of battery cells; a thermal expansion material at least partially positioned between the plurality of battery cells; Equipped with The thermal expansion material at least partially surrounds at least a portion of an area existing between the plurality of battery cells.

2. The battery module according to claim 1 , wherein the at least a portion of the region overlaps a central portion of the battery cell.

3. The battery module of claim 1 or 2, further comprising a compression pad at least partially located in said at least a portion of said region.

4. The battery module according to claim 1 or 2, wherein the thermal expansion material at least partially includes a foam material.

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