Battery module

Abstract

To provide a technique of discharging gas generated inside a battery module to the outside as appropriate.SOLUTION: A battery module 100 includes a multilayer body 101 where a plurality of battery cells 110 are stacked in a thickness direction, an accommodation body (housing) that accommodates the multilayer body 101, and a plurality of fixed layers 500 that fix a surface of the accommodation body that faces a cell side surface 113 of the battery cell 110, and the cell side surface 113 of the battery cell 110. The fixed layers 500 cover 50% or more of a target surface (multilayer body side surface 103) of the multilayer body 101 that corresponds to the cell side surface 113 of the battery cell 110.SELECTED DRAWING: Figure 3

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 a plurality of battery cells stacked in a predetermined direction and a housing that houses the plurality of battery cells.

[0003] Patent Documents 1 and 2 describe battery modules. The battery module is a stack of multiple battery cells. Both the upper and lower surfaces of the stack are fixed to a housing that houses the stack with a thermally conductive adhesive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Chinese Utility Model No. 215816165 [Patent Document 2] Chinese Utility Model No. 213026370 Summary of the Invention [Problem to be solved by the invention]

[0005] In battery modules, gas is generated due to deterioration inside the battery, overcharging, and over-discharging, and the generated gas needs to be properly released to the outside.

[0006] An example of an object of the present invention is to provide a technique for appropriately releasing gas generated inside a battery module to the outside. [Means for solving the problem]

[0007] The present invention provides the following techniques. 1. A laminate in which multiple battery cells are stacked in the thickness direction; a container that contains the stack; a fixing layer that fixes a surface of the housing that faces a side surface of the battery cell to the side surface of the battery cell; and The fixing layer covers 50% or more of a target surface of the stack, which corresponds to a side surface of the battery cell. 2. The battery module according to 1., wherein a plurality of the fixing layers are provided. 3. The battery module according to 1. or 2., wherein at least one of the plurality of fixing layers extends in a direction intersecting all of the cells. 4. The battery module according to 1. or 2., wherein the width of the gap between adjacent fixing layers is 0.2 to 5 times the width of the fixing layer. [Effects of the Invention]

[0008] According to the above aspect of the present invention, it is possible to provide a technique for appropriately releasing gas generated inside a battery module to the outside. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is an exploded perspective view of the upper side of the battery module according to the first embodiment. [Figure 2] FIG. 2 is a view focusing on the cell side surfaces of adjacent battery cells according to the first embodiment. [Figure 3] 3A to 3C are diagrams illustrating examples of the arrangement of fixing layers provided on the upper surface of the stack according to the first embodiment. [Figure 4] 10A and 10B are diagrams illustrating an example of the arrangement of a fixing layer provided on the upper surface of a stack according to a second embodiment. [Figure 5] 10A and 10B are diagrams illustrating an example of the arrangement of a fixing layer provided on the upper surface of a stack according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] First Embodiment <Battery module overview> Fig. 1 is an exploded perspective view of the top of a battery module 100 according to an embodiment. Fig. 2 is an enlarged view of a cell side surface 113 of a battery cell.

[0012] 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.

[0013] 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 container 200, an adhesive 300, and a fixing layer 500.

[0014] <Laminate> The multiple battery cells 110 and the multiple compression pads 120 are stacked alternately in the Y direction. Each compression pad 120 is disposed between adjacent battery cells 110 in the Y direction and on both sides of the multiple battery cells 110 in the Y direction. Hereinafter, the multiple battery cells 110 and the multiple compression pads 120 stacked alternately in the Y direction will be referred to as a stack 101 of battery cells 110. The laminate 101 is a rectangular parallelepiped as a whole. Here, the rectangular parallelepiped does not only refer to a perfect rectangular parallelepiped, but also allows for the existence of irregularities and curves on each face and edge that are due to the shapes of the battery cells 110, compression pads 120, and the like that make up the laminate 101. In this embodiment, the surface on the +Z side of the laminate 101 will be referred to as the laminate side surface 103.

[0015] <Battery cell> The battery cell 110 has a thin rectangular parallelepiped shape with a rectangular surface (main surface) when viewed from the Y direction. Here, "rectangle" does not mean a perfect rectangle, but rather allows for unevenness, curved surfaces, etc. on each side that constitutes the rectangle. "Rectangular parallelepiped" does not only mean a perfect rectangular parallelepiped, but also allows for unevenness, curved surfaces, etc. on each face and side that constitutes the rectangular parallelepiped. The X-direction dimension of each battery cell 110 is the longitudinal dimension of each battery cell 110. The Z-direction dimension of each battery cell 110 is the lateral dimension of each battery cell 110. The Y-direction dimension of each battery cell 110 is the thickness dimension of each battery cell 110. The shape of each battery cell 110 is not limited to this example. In this embodiment, the surface visible from the +Z side of the battery cell 110 will be referred to as the cell side surface 113. The above-mentioned stack side surface 103 can also be said to be a surface formed by an assembly of the cell side surfaces 113. In other words, in the stack 101, the target surface corresponding to the cell side surface 113 of the battery cell 110 is the stack side surface 103.

[0016] The 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 the positive electrodes and negative electrodes adjacent in the Y direction. The battery element and an electrolyte (not shown) are sealed in the exterior material 112. The positive electrode tab 114 is electrically connected to the positive electrode of the battery element. On the side of the exterior material 112, a sealing edge 119 is provided as a structure associated with sealing (so-called sealing margin), extending from the cell body 111. For example, FIG. 2 shows the sealing edge 119 on the +Z side. The sealing edge 119 on the +Z side is bent so as to be parallel to the laminate side surface 103. In other words, it can be said that at least a portion of the sealing edge 119 is included in the laminate side surface 103. The bending directions of the sealing edges 119 may be the same direction or may be alternately different directions (+Y direction, -Y direction). The positive electrode tab 114 is pulled out from one of the two sides in the X direction of the exterior material 112. The negative electrode tab 116 is electrically connected to the negative electrode of the battery element. The negative electrode tab 116 is pulled out from the other of the two sides in the X direction of the exterior material 112. 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.

[0019] On the +X side of the stack 101 of battery cells 110, a positive electrode tab 114 drawn out from a battery cell 110 of one cell group connected in parallel and a negative electrode tab 116 drawn out 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.

[0020] The positive electrode tabs 114 and the negative electrode tabs 116 in the tab group 118 are joined to each other by, for example, laser welding. The tab group 118 is similarly located on the -X side of the stack 101 of battery cells 110. Therefore, multiple cell groups are connected in series from the cell group located at one end side of the stack 101 of battery cells 110 in the Y direction to the cell group located at the other end side of the stack 101 of battery cells 110 in the Y direction. Hereinafter, as necessary, the tab group 118 located on the +X side of the stack 101 of the 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 101 of the battery cells 110 will be referred to as the -X side tab group 118.

[0021] The electrical connection of the plurality of battery cells 110 is not limited to the above example. For example, the stack 101 of battery cells 110 may be configured by connecting single battery cells 110 in series.

[0022] <First voltage detection device> 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.

[0023] The first protector 131 covers the +X side portion of the stack 101 of battery cells 110. The first protector 131 is, for example, 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.

[0024] 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 101 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.

[0025] 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.

[0026] 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 101 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.

[0027] <Second voltage detection device> 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.

[0028] The second protector 141 covers the -X side portion of the stack 101 of battery cells 110. The second protector 141 is, for example, an insulator 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.

[0029] 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 101 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.

[0030] 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.

[0031] 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 101 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.

[0032] <Positive and negative electrode tab arrangement> 1 , the positive electrode tabs 114 at the ends of the multiple serially connected cell groups are drawn out toward the +X side from the battery cells 110 of the cell groups located at the end portion on the +Y side of the stack 101 of battery cells 110, and the negative electrode tabs 116 at the ends of the multiple serially connected cell groups are drawn out toward the -X side from the battery cells 110 of the cell groups located at the end portion on the -Y side of the stack 101 of battery cells 110. Thus, the first bus bar 135 is disposed on the +X side and the +Y side of the stack 101 of battery cells 110, and the second bus bar 145 is disposed on the -X side and the -Y side of the stack 101 of battery cells 110. However, the arrangement of the positive electrode tabs 114 and the negative electrode tabs 116 at the ends of the multiple serially connected cell groups may differ depending on the number of battery cells 110 included in the stack 101 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 101 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 101 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 101 of battery cells 110, and the second bus bar 145 is arranged on the -X side and the -Y side of the stack 101 of battery cells 110.

[0033] <Containment Unit (Housing)> The container 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.

[0034] The first plate 210 is a metal plate such as an aluminum plate, and covers the +X side portion of the stack 101 of battery cells 110 and the +X side portion of the first voltage detection device 130. The first plate 210 is provided with a plurality of gas release portions 155 that penetrate the first plate 210 in the thickness direction and provide communication between the inside and outside of the housing 200. The shape of the gas release portions 155 is, for example, circular when viewed from the +X side. The shape of the gas release portions 155 is not limited to circular, and various shapes can be used as long as they have a gas release function. Furthermore, the shapes and sizes of all the gas release portions 155 may be the same or different.

[0035] The second plate 220 is a metal plate such as an aluminum plate, and covers the -X side portion of the stack 101 of battery cells 110 and the -X side portion of the second voltage detection device 140. The second plate 220 is provided with a plurality of gas release portions 255 that penetrate through the second plate 220 in the thickness direction and provide communication between the inside and outside of the housing 200. The shape of the gas release portions 255 is, for example, circular when viewed from the -X side. The shape of the gas release portions 255 is not limited to circular, and various shapes can be used as long as they have a gas release function. The shapes and sizes of all the gas release portions 255 may be the same or different.

[0036] The third plate 230 is, for example, a metal plate such as an aluminum plate, and covers the portion of the stack 101 of the battery cells 110 on the +Y side (ie, the stack side surface 103).

[0037] The fourth plate 240 is, for example, a metal plate such as an aluminum plate, and covers the portion of the stack 101 of battery cells 110 on the -Y side.

[0038] The fifth plate 250 is, for example, a metal plate such as an aluminum plate, and covers the +Z side portion of the stack 101 of battery cells 110.

[0039] The sixth plate 260 is, for example, a metal plate such as an aluminum plate, and covers the portion of the stack 101 of battery cells 110 on the -Z side.

[0040] <Overview of the upper and lower fixing structure for the stack (battery cells)>

[0041] In the laminate 101, the -Z side portion is fixed to the sixth plate 260 by adhesive 300, and the +Z side portion, i.e., the laminate side surface 103, is fixed to the fifth plate 250 by fixing layer 500.

[0042] The adhesive 300 has thermal conductivity. The adhesive 300 is, for example, a thermally conductive adhesive such as a silicone adhesive or a urethane adhesive. The adhesive 300 is at least partially located between the -Z side surface of the stack 101 of battery cells 110 and the +Z side surface of the sixth plate 260 in the Z direction. Therefore, heat generated from the stack 101 of battery cells 110 can be released toward the sixth plate 260 via the adhesive 300. However, the adhesive 300 does not have to have thermal conductivity.

[0043] The fixing layer 500 is a thermally conductive adhesive such as a silicone adhesive or a urethane adhesive. In the Z direction, the fixing layer 500 is partially located between the +Z side surface (stack side surface 103) of the stack 101 of battery cells 110 and the -Z side surface of the fifth plate 250 (i.e., the inner surface of the housing 200). This structure allows heat generated from the stack 101 of battery cells 110 to be released toward the fifth plate 250 via the fixing layer 500. However, the fixing layer 500 does not have to be thermally conductive. Hereinafter, the adhesive 300 and the fixing layer 500 are formed by curing an adhesive in a liquid or gel state before curing (hereinafter referred to as uncured adhesive). The specific shape, arrangement, etc. of the fixed layer 500 will be described later.

[0044] A method for fixing the stack 101 to the container 200 will be described. In this embodiment, a first step is performed in which the stack 101 is fixed to the sixth plate 260, which will be the bottom surface of the housing body 200, using adhesive 300. Next, a second step is performed in which the first plate 210, the second plate 220, the third plate 230, and the fourth plate 240 are bonded around the periphery of the sixth plate 260. Furthermore, a third step is performed in which the fifth plate 250, which will be the lid of the housing body 200, is fixed to the top surface (stack body side surface 103) of the stack 101 using a fixing layer 500.

[0045] The first step will be explained. An uncured adhesive is applied to the +Z side surface of the sixth plate 260. Next, the stack 101 of battery cells 110 is placed on the +Z side surface of the sixth plate 260 via the uncured adhesive. Next, the uncured adhesive is cured to change the uncured adhesive into adhesive 300. There are no particular limitations on the method for curing the uncured adhesive, and examples include drying, heating, and light irradiation. In this way, the stack 101 is fixed to the sixth plate 260.

[0046] The second step will be described. After the laminate 101 is fixed to the +Z side surface of the sixth plate 260 with the adhesive 300, the first plate 210, the second plate 220, the third plate 230 and the fourth plate 240 are joined around the periphery of the sixth plate 260. Specifically, the -Z side end of the first plate 210 and the +X side end of the sixth plate 260 are joined to each other by a joining method such as laser welding, and the -Z side end of the second plate 220 and the +X side end of the sixth plate 260 are joined to each other by a joining method such as laser welding. Furthermore, the -Z side end of the third plate 230 and the +Y side end of the sixth plate 260 are joined to each other by a joining method such as laser welding, and the -Z side end of the fourth plate 240 and the -Y side end of the sixth plate 260 are joined to each other by a joining method such as laser welding.

[0047] The third step will be explained. An uncured adhesive is applied to the +Z side surface of the fifth plate 250 (i.e., the inner surface of the housing 200). Next, the -Z side surface of the fifth plate 250 to which the uncured adhesive has been applied is placed on the stack side surface 103 of the stack 101 of battery cells 110. Next, the uncured adhesive is cured to form the fixing layer 500. The method for curing the uncured adhesive is not particularly limited, and examples include drying, heating, and light irradiation. As a result, the stack side surface 103 of the stack 101 is fixed to the fifth plate 250.

[0048] <Upper fixing structure of stacked body (battery cell) 1> The fixing structure between the upper surface (laminate side surface 103) of the laminate 101 and the fifth plate 250 will be described in more detail with reference to Fig. 3. Fig. 3 is a diagram illustrating an example of the arrangement of a fixing layer 500 provided on the laminate side surface 103 of the laminate 101. The shape and arrangement of the fixing layer 500 can also be said to be the arrangement formed when uncured adhesive is applied to the -Z side surface of the fifth plate 250.

[0049] The multiple fixing layers 500 cover a surface formed as a group of the cell side surfaces 113 of the battery cells 110, that is, 50% or more of the stack side surface 103 of the stack 101.

[0050] The lower limit of the proportion of the stack side surface 103 covered by the fixing layer 500 is preferably 60% or more, and more preferably 70% or more. There is no particular upper limit, but from the viewpoint of providing a gas layer 550 in the gap between the fixing layers 500, it is 95% or less, preferably 90% or less, and more preferably 85% or less. The gas layer 550 is connected to a release valve. The release valve is provided, for example, in the fifth plate 250 that contacts the gas layer 550. In other words, the gas layer 550 has no area surrounded by the fixing layer 500 in the X direction and the Y direction.

[0051] By making the area of ​​the fixing layer 500 50% or more, the area (gas layer 550) that accumulates gas generated from the battery cells 110 can be limited to a certain range. Note that if the area of ​​the fixing layer 500 exceeds 95%, the gas discharge area becomes too small, which may result in excessive pressure inside the housing 200, or the rate of pressure increase, resulting in an excessively fast gas discharge rate. If the discharged high-temperature gas is exposed to another battery module 100, a chain reaction may occur in which the other battery module 100 becomes hot and generates gas inside. Therefore, it is necessary to control the gas discharge rate within an appropriate range. In this embodiment, the position and volume of the gas layer 550 where gas accumulates can be limited to a certain range, thereby controlling the gas discharge rate and discharge location. Furthermore, the gas layer 550 is connected to a release valve, and by ensuring that there is no area surrounded by the fixing layer 500 in the X and Y directions, the pressure inside the battery module 100 can be kept below a predetermined level.

[0052] A plurality of fixed layers 500 are provided. Here, first to eighth fixed layers 501 to 508 are arranged in order as fixed layers 500 from the first plate 210 side (+X side) to the second plate 220 side (-X side). When there is no need to distinguish between the first to eighth fixed layers 501 to 508, they will be simply referred to as "fixed layers 500."

[0053] When viewed from the Z direction, each of the first to eighth fixed layers 501 to 508 has an elongated (or strip-like) shape with its longitudinal direction extending in the horizontal direction (Y direction) perpendicular to the extension direction of the cell side surface 113 (i.e., the X direction).

[0054] At least one of the multiple fixing layers 500 intersects with all of the battery cells 110. In this embodiment, the second to eighth fixing layers 502 to 508 intersect with all of the battery cells 110.

[0055] First fixed layer 501 is composed of two parts: first fixed layer (A) 501a on the +Y direction side and first fixed layer (B) 501b. First fixed layer (A) 501a and first fixed layer (B) 501b are separated at the middle position in the Y direction. The separated portion forms a gas layer 560. When first fixed layer (A) 501a and first fixed layer (B) 501b are not to be distinguished, they will be simply referred to as "first fixed layer 501."

[0056] The first to fourth fixed layers 501 to 504 are integrated so that adjacent longitudinal sides of each component coincide with each other when viewed from above. "Coinciding" means that there is substantially no gas layer 550 between adjacent fixed layers 500. Therefore, the portions where adjacent fixed layers 500 coincide with each other do not need to be flush with each other. Specifically, the -X side edge of first fixed layer 501 and the +X side edge of second fixed layer 502 are in contact. The -X side edge of second fixed layer 502 and the +X side edge of third fixed layer 503 are in contact. The -X side edge of third fixed layer 503 and the +X side edge of fourth fixed layer 504 are in contact.

[0057] Fifth to eighth fixed layers 505 to 508 are integrated such that adjacent longitudinal sides of each component coincide when viewed from above. Specifically, the -X side of fifth fixed layer 505 contacts the +X side of sixth fixed layer 506. The -X side of sixth fixed layer 506 contacts the +X side of seventh fixed layer 507. The -X side of seventh fixed layer 507 contacts the +X side of eighth fixed layer 508.

[0058] The fourth fixed layer 504 and the fifth fixed layer 505 are spaced apart, and the gap between them forms a gas layer 550. Gas generated in the battery cell 110 accumulates in the gas layer 550.

[0059] <Gas flow> The gas generated in the battery cell 110 passes through the gaps inside the stack 101, i.e., the gaps formed between the battery cell 110 and the compression pad 120, and is released to the outside from the gas release section 155 of the first plate 210 and the gas release section 155 of the second plate 220.

[0060] Furthermore, some of the gas generated in the battery cell 110 temporarily accumulates in a gas layer 550 between the fourth fixing layer 504 and the fifth fixing layer 505. The gas then passes through gaps inside the laminate 101 and is gradually released to the outside from the gas release portions 155, 255. Note that a gas release portion such as a release valve may be provided in the fifth plate 250 at a position corresponding to the position where the gas layer 550 is provided. When the pressure becomes too high due to excess gas, the gas can be released through the release valve, and the pressure in the gas layer 550 can be controlled within an appropriate range.

[0061] The gas layer 550 functions as a buffer that temporarily stores gas. Therefore, even if a large amount of gas is generated due to deterioration, over-discharge, or over-charge of the battery cell 110, it is possible to suppress a sudden increase in pressure inside the housing 200 and a sudden increase in the rate at which the gas is discharged. As a result, even if the gas becomes excessively hot and a symptom occurs in which a battery cell 110 is overheated and damaged, it is possible to lengthen the time until the symptom spreads to another battery cell 110. For example, even if a malfunction occurs in a vehicle equipped with the battery module 100, such as a fire in the battery module 100, the time from the occurrence of the malfunction to the fire can be sufficiently long, and the time required for the vehicle occupants to evacuate (for example, the time required by laws and regulations) can be sufficiently secured.

[0062] <Second embodiment> A second embodiment will be described with reference to Fig. 4. Fig. 4 is a diagram illustrating an example of the arrangement of a fixed layer 500 provided on the upper surface of the laminate 101 of this embodiment. In this embodiment, adjacent fixed layers 500 are spaced apart. That is, a gas layer 550 is provided between adjacent fixed layers 500.

[0063] Specifically, first to sixth fixing layers 501 to 506 are provided as fixing layer 500. The area of ​​laminate side surface 103 covered by first to sixth fixing layers 501 to 506 is 50% or more of the entire area of ​​laminate side surface 103.

[0064] When viewed from the Z direction, each of the first to sixth fixed layers 501 to 506 has an elongated (or strip-like) shape with its longitudinal direction extending in the lateral direction (Y direction) perpendicular to the extension direction of the cell side surface 113 (i.e., the X direction). In this embodiment, the first and sixth fixed layers 501, 506 are the thinnest, the second and fifth fixed layers 502, 505 are the thickest, and the third and fourth fixed layers 503, 504 are of intermediate thickness. The first to sixth fixed layers 501-506 are shaped and arranged to be roughly symmetrical in the front-to-back direction (left-to-right in FIG. 4) with respect to the center in the X direction.

[0065] First fixed layer 501 is composed of two parts: first fixed layer (A) 501a on the +Y direction side and first fixed layer (B) 501b. First fixed layer (A) 501a and first fixed layer (B) 501b are separated at the middle position in the Y direction. The separated portion forms a gas layer 560. When first fixed layer (A) 501a and first fixed layer (B) 501b are not to be distinguished, they will be simply referred to as "first fixed layer 501."

[0066] Among the first to sixth fixed layers 501 to 506, adjacent fixed layers 500 in the X direction are spaced apart to form a gas layer 550. Specifically, first fixed layer 501 and second fixed layer 502 are spaced apart in the X direction. The gap between first fixed layer 501 and second fixed layer 502 forms first gas layer 551. Second fixed layer 502 and third fixed layer 503 are spaced apart in the X direction. The gap between second fixed layer 502 and third fixed layer 503 forms second gas layer 552. Third fixed layer 503 and fourth fixed layer 504 are spaced apart in the X direction. The gap between third fixed layer 503 and fourth fixed layer 504 forms third gas layer 553. Fourth fixed layer 504 and fifth fixed layer 505 are spaced apart in the X direction. The gap between fourth fixed layer 504 and fifth fixed layer 505 forms fourth gas layer 554. Fifth fixed layer 505 and sixth fixed layer 506 are spaced apart in the X direction. The gap between fifth fixed layer 505 and sixth fixed layer 506 forms fifth gas layer 555.

[0067] When the first to fifth gas layers 551 to 555 are not to be distinguished from one another, they will be simply referred to as "gas layers 550." In this embodiment, the first to fifth gas layers 551 to 555 have the same width (length in the +X direction). However, the widths of the first to fifth gas layers 551 to 555 are not necessarily limited to being the same.

[0068] The width of the gap between adjacent fixed layers 500 (ie, the gas layer 550 ) is 0.2 to 5 times the width of the fixed layer 500 .

[0069] In this embodiment, the width of the gas layer 550 is 0.2 times the width of the widest fixed layer 500 among the multiple fixed layers 500 (second fixed layer 502, fourth fixed layer 504), and is 5 times the width of the narrowest fixed layer 500 among the multiple fixed layers 500 (first fixed layer 501, sixth fixed layer 506).

[0070] By setting the relationship between the width of the gas layer 550 and the width of the fixed layer 500 within an upper range, it is possible to store a sufficient amount of gas in the gas layer 550, while suppressing the speed at which the gas moves outward (in the +X direction or the -X direction) through the gas layer 550 to an appropriate level. In other words, it is possible to appropriately adjust the gas movement speed.

[0071] <Third embodiment> A third embodiment will be described with reference to Fig. 5. Fig. 5 is a diagram illustrating an example of the arrangement of a fixed layer 500 provided on the upper surface of the laminate 101 of this embodiment. In this embodiment, adjacent fixed layers 500 are spaced apart. That is, a gas layer 550 is provided between adjacent fixed layers 500.

[0072] Specifically, first to fourth fixing layers 501 to 504 are provided as fixing layer 500. The area of ​​laminate side surface 103 covered by first to fourth fixing layers 501 to 504 is 50% or more of the entire area of ​​laminate side surface 103.

[0073] When viewed from the Z direction, each of the first to fourth fixed layers 504-504 has an elongated (or strip-like) shape with its longitudinal direction extending in the horizontal direction (Y direction) perpendicular to the extension direction of the cell side surface 113 (i.e., the X direction). In this embodiment, the first and fourth fixed layers 501 and 504 are the thinnest, the third fixed layer 503 is the thickest, and the second fixed layer 502 is of intermediate thickness.

[0074] First fixed layer 501 is composed of two parts: first fixed layer (A) 501a on the +Y direction side and first fixed layer (B) 501b. First fixed layer (A) 501a and first fixed layer (B) 501b are separated at the middle position in the Y direction. The separated portion forms a gas layer 560. When first fixed layer (A) 501a and first fixed layer (B) 501b are not to be distinguished, they will be simply referred to as "first fixed layer 501."

[0075] The first to fourth fixed layers 501 to 504 are each spaced apart from each other between adjacent fixed layers 500 in the X direction, forming a gas layer 550 . Specifically, first fixed layer 501 and second fixed layer 502 are spaced apart in the X direction. The gap between first fixed layer 501 and second fixed layer 502 forms first gas layer 551. Second fixed layer 502 and third fixed layer 503 are spaced apart in the X direction. The gap between second fixed layer 502 and third fixed layer 503 forms second gas layer 552. Third fixed layer 503 and fourth fixed layer 504 are spaced apart in the X direction. The gap between third fixed layer 503 and fourth fixed layer 504 forms third gas layer 553. When the first to fourth gas layers 551 to 554 are not to be distinguished from one another, they will be simply referred to as "gas layers 550." In this embodiment, the first and second gas layers 551 and 552 have the same width (length in the +X direction). The width of the third gas layer 553, which is provided on the rearmost side (closest to the -X direction), is set to be much wider (about six times wider in this case) than the first and second gas layers 551 and 552. The width of the third fixed layer 503 and the width of the third gas layer 553 are also approximately the same.

[0076] With this configuration, a large amount of gas can be stored in the third gas layer 553. In addition, the width of the third fixed layer 503 adjacent to the third gas layer 553 on the +X side is set to be as wide as about 30% of the length of the cell side surface 113 in the +X direction, so that the gas in the third gas layer 553 does not easily move forward (in the +X direction) to the second gas layer 552.

[0077] 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.

[0078] <Summary of the embodiment> The features of this embodiment can be summarized as follows: 1. A stack 101 in which a plurality of battery cells 110 are stacked in the thickness direction; a housing 200 (casing) that houses the stack 101; a fixing layer (500) that fixes a surface (251) of the housing (200) that faces the cell side surface (113) of the battery cell (110) to the cell side surface (113) of the battery cell (110); and The fixing layer 500 covers 50% or more of the target surface (laminated body side surface 103) of the laminate 101 that corresponds to the cell side surface 113 of the battery cell 110 of the laminate 101. 2. The battery module 100 according to 1., wherein a plurality of the fixing layers 500 are provided. 3. The battery module 100 according to 1 or 2, wherein at least one of the plurality of fixing layers 500 extends in a direction intersecting all of the battery cells 110. 4. The battery module 100 according to 1. or 2., wherein the width of the gap (gas layer 550 ) between adjacent fixing layers 500 is 0.2 to 5 times the width of the fixing layer 500 . [Explanation of symbols]

[0079] 100 Battery Module 1 101 laminate 103 Laminated body side 110 battery cells 111 Cell body 113 Cell side 119 Sealing side 120 compression pad 130 First voltage detection device 1 140 Second voltage detection device 155, 255 Gas release section 200 units 210 First Plate 220 Second Plate 230 Third Plate 240 4th Plate 250 5th Plate 260 6th Plate 300 Adhesive 500 fixed layer 501~506 1st~6th fixed layer 550 Gas Layer 551~555 1st~5th gas layers

Claims

1. a stack in which a plurality of battery cells are stacked in the thickness direction; a container that contains the stack; a fixing layer that fixes a surface of the housing that faces a side surface of the battery cell to the side surface of the battery cell; and The fixing layer covers 50% or more of a target surface of the stack that corresponds to a side surface of the battery cell.

2. The battery module according to claim 1 , wherein a plurality of the fixing layers are provided.

3. The battery module according to claim 1 , wherein at least one of the plurality of fixing layers extends in a direction intersecting all of the battery cells.

4. 3. The battery module according to claim 1, wherein the width of the gap between adjacent fixing layers is 0.2 to 5 times the width of the fixing layer.

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