Cell stack, battery assembly, and vehicle

Abstract

This cell stack comprises a pair of busbar housings extending along the horizontal direction, a cell laminate, and a jig. The cell laminate is disposed between the pair of busbar housings and includes a plurality of cells laminated along the horizontal direction. Each of the plurality of cells comprises two or more electrode tabs projecting toward one of the pair of busbar housings, and two or more electrode tabs projecting toward the other of the pair of busbar housings. The jig is configured to clamp the cell laminate from both sides and apply a pressure between 20 kPa and 350 kPa, inclusive, in the horizontal direction to the plurality of cells. The jig comprises a first lateral face, a second lateral face opposite the first lateral face, and a bottom face extending in the horizontal direction from a bottom edge of the first lateral face to a bottom edge of the second lateral face.

Description

Cell stack, battery assembly and vehicle

[0001] The present invention relates to a cell stack, a battery assembly, and a vehicle.

[0002] Patent Document 1 discloses a battery pack that includes a plurality of battery modules, each including a battery cell stack formed by stacking a plurality of battery cells, a pack frame that houses the battery modules, and a module frame that houses the battery cell stack.

[0003] JP 2024-45691 A

[0004] The present disclosure provides techniques for improving the energy density of battery assemblies.

[0005] In an exemplary embodiment of the present disclosure, there is provided a cell stack comprising: a pair of bus bar housings extending along a horizontal direction; a cell stack disposed between the pair of bus bar housings, the cell stack including a plurality of cells stacked along the horizontal direction, each cell of the plurality of cells having two or more electrode tabs protruding toward one of the pair of bus bar housings and two or more electrode tabs protruding toward the other of the pair of bus bar housings; and a jig configured to sandwich the cell stack from both sides and apply a pressure of 20 kPa to 350 kPa in the horizontal direction to the plurality of cells, the jig having a first side surface, a second side surface opposite the first side surface, and a bottom surface extending along the horizontal direction from a lower end of the first side surface to a lower end of the second side surface.

[0006] According to the present invention, a technique for improving the energy density of a battery assembly can be provided.

[0007] FIG. 1 is a perspective view illustrating an example of the configuration of a battery assembly 1. FIG. 2 is an exploded perspective view illustrating an example of the configuration of a cell stack 2. FIG. 3 is a perspective view illustrating an example of the configuration of a cell laminate 20. FIG. 4 is a perspective view illustrating an example of the configuration of a cell 200. FIG. 5 is a diagram illustrating an example of the connection between a cell stack housing 26 and a housing 3. FIG. 6 is a perspective view illustrating an example of the configuration of the housing 3. FIG. 7 is an exploded perspective view illustrating an example of the configuration of the housing 3. FIG. 8 is a schematic diagram illustrating an example of a vehicle M equipped with the battery assembly 1.

[0008] Hereinafter, each embodiment of the present disclosure will be described.

[0009] In one exemplary embodiment, there is provided a cell stack comprising: a pair of bus bar housings extending along a horizontal direction; a cell stack disposed between the pair of bus bar housings, the cell stack including a plurality of cells stacked along the horizontal direction, each cell of the plurality of cells having two or more electrode tabs protruding toward one of the pair of bus bar housings and two or more electrode tabs protruding toward the other of the pair of bus bar housings; and a jig configured to sandwich the cell stack from both sides and apply a pressure of 20 kPa to 350 kPa in the horizontal direction to the plurality of cells, the jig having a first side surface, a second side surface opposite the first side surface, and a bottom surface extending along the horizontal direction from a lower end of the first side surface to a lower end of the second side surface.

[0010] In one exemplary embodiment, the jig has a substantially U-shaped vertical cross section along the horizontal direction.

[0011] In one exemplary embodiment, each cell includes a sealed container that houses the electrode stack, and the sealed container is a substantially rectangular bag having a pair of short sides and a pair of long sides.

[0012] In one exemplary embodiment, the cells are arranged in the cell stack so that the direction in which a pair of short sides of the sealed container extend is vertically up and down.

[0013] In one exemplary embodiment, the polarity of the electrode tabs extending from the top half of one short side of the sealed container is different from the polarity of the electrode tabs extending from the top half of the other short side of the sealed container.

[0014] In one exemplary embodiment, the electrode stack includes a current collector having a resin layer and a pair of conductive layers provided on both sides of the resin layer.

[0015] In one exemplary embodiment, a battery assembly is provided that includes at least one cell stack and a housing that houses the at least one cell stack.

[0016] In one exemplary embodiment, the jig has a first connection portion extending from the upper end of the first side and a second connection portion extending from the upper end of the second side, and the cell stack is configured to be fixed to the housing by coupling the first connection portion and the second connection portion to the housing with fastening members.

[0017] In one exemplary embodiment, at least one of the first connecting portion and the second connecting portion includes a hole portion into which the fastening member is inserted, the hole portion having a horizontal diameter larger than the nominal diameter of the fastening member.

[0018] In one exemplary embodiment, a vehicle is provided that includes a battery assembly and a motor powered by the battery assembly.

[0019] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or similar elements are denoted by the same reference numerals, and redundant description will be omitted. The dimensional ratios in the drawings do not represent actual ratios, and the actual ratios are not limited to the illustrated ratios. In each drawing, the x-axis and y-axis may be horizontal, the z-axis may be vertical, and the positive direction of the z-axis may be referred to as "upper" or "upward," and the negative direction of the z-axis may be referred to as "lower" or "downward."

[0020] [Overall Configuration of Battery Assembly 1] Figure 1 is a perspective view illustrating an example of the configuration of a battery assembly 1 according to one embodiment. The battery assembly 1 includes a cell stack 2 and a housing 3 configured to house the cell stack 2. The cell stack 2 may be detachably housed in the housing 3 via a restraining holder or the like. The housing 3 includes side walls 30 that surround the side surfaces of the cell stack 2 and a bottom plate 31 that supports the underside of the cell stack 2.

[0021] In one embodiment, the housing 3 may be configured to accommodate a plurality of cell stacks 2. In this case, the housing 3 may include a plurality of bus bars 4 that electrically connect the cell stacks 2 together. The bus bars 4 may be made of a conductive material such as copper, aluminum, nickel, or an alloy thereof. The arrangement of the bus bars 4 and the connections between the bus bars 4 can be set as appropriate, thereby defining the electrical connection relationship (series, parallel) of the cell stacks 2. In the example shown in FIG. 1 , six cell stacks 2 are connected in series. The plurality of cell stacks 2 may be arranged in an array along a horizontal plane (xy plane).

[0022] [Configuration of Cell Stack 2] An example of the configuration of the cell stack 2 will be described with reference to Figures 2 to 5. Here, Figure 2 is an exploded perspective view for explaining an example of the configuration of the cell stack 2. Figure 3 is a perspective view for explaining an example of the configuration of the cell laminate 20. Figure 4 is a perspective view showing an example of the configuration of the cell 200. Figure 5 is a diagram for explaining an example of the connection between the cell stack housing 26 and the housing 3.

[0023] As shown in FIG. 2, the cell stack 2 may include a cell laminate 20, a compression pad 21, a pair of bus bar housings 22 (22A, 22B), a pair of thermally conductive sheets 23 (23A, 23B), a pair of gas control plates 24 (24A, 24B), an insulating sheet 25, and a cell stack housing 26.

[0024] <Cell Stack 20> As shown in Fig. 3, the cell stack 20 is configured to include a plurality of cells 200. The cells 200 are stacked in the horizontal direction (the x-axis direction in Fig. 3). The cells 200 may be pouch-type cells (also referred to as "pouch cells").

[0025] As shown in FIG. 4 , the cell 200 includes a sealed container 201 and electrode tabs 202 to 205 extending from the sealed container 201. The electrode tabs are sometimes referred to as "leads." An electrode stack (not shown) is housed inside the sealed container 201. The electrode stack may be constructed by stacking multiple sets (e.g., 10 to 50 sets) of positive electrodes, separators, and negative electrodes. In one embodiment, the electrode stack is a lithium secondary battery. The electrode stack may be housed in the sealed container 201 together with an electrolyte. The electrolyte may be a solution that fills the sealed container 201, may be impregnated into the separator of the electrode stack, or may be held in a polymer to form a polymer electrolyte or a gel electrolyte. The electrode tabs 202 to 205 are electrically connected to either the positive electrode current collector or the negative electrode current collector of the electrode stack.

[0026] In one embodiment, the positive and / or negative electrode current collectors of the electrode stack may be formed by sandwiching a resin layer between a pair of conductive layers. Such resin layers may be formed of sheet-like or fibrous resins. The resin may be, for example, at least one of polyolefin resins such as polyethylene terephthalate, polyethylene, and polypropylene, and thermoplastic resins such as polystyrene, polyvinyl chloride, and polyamide. When the current collector includes a resin layer, the resin layer may melt in the event of abnormal heat generation due to overcharge or high temperature, damaging the electrode to which the current collector is connected and interrupting short-circuit current within the battery. This may suppress a sudden temperature rise within the cell and prevent the cell from igniting. In one embodiment, when the electrode stack includes multiple positive electrode current collectors and multiple negative electrode current collectors, at least one of the multiple positive electrode current collectors and the multiple negative electrode current collectors may be a current collector including a resin layer. At least one of the multiple positive electrode current collectors and the multiple negative electrode current collectors may be formed solely of a conductive material without including a resin layer.

[0027] 4, the sealed container 201 may be a substantially rectangular bag having a pair of long sides and a pair of short sides. The ratio (L / W) of the length W (mm) of the short side to the length L (mm) of the long side of the sealed container 201 may be 1.5<L / W<10.0, 2.0<L / W<5.0, or 2.5<L / W<5.0.

[0028] The sealed container 201 may be formed, for example, by overlapping a pair of sheet members and sealing them around their peripheries. The sealed container 201 may be formed, for example, by folding one sheet member and sealing the remaining peripheral portion. In this case, the folded portion may form one of the long sides of the sealed container. The sheet member may be formed from multiple layers. For example, the sheet member may be formed by covering both sides of a thin metal sheet with a resin film. The sheet member may be, for example, an aluminum laminate film.

[0029] In one embodiment, two electrode tabs 202 and 203 are drawn out, one above the other, from one short side of the sealed container 201. Two electrode tabs 204 and 205 are drawn out, one above the other, from the other short side of the sealed container 201. An insulating material 206 such as a sealant film may be interposed between each of the electrode tabs 202 to 205 and the sealed portion of the sealed container 201. In one embodiment, three or more electrode tabs may be drawn out from one or both short sides of the sealed container 201.

[0030] In one embodiment, the polarities of the electrode tabs extending from the same short side may be different. For example, the polarities of electrode tab 202 and electrode tab 203 may be different. Also, the polarities of electrode tab 204 and electrode tab 205 may be different.

[0031] In one embodiment, the polarity of the electrode tabs extending from the upper half (or lower half) of one short side of the sealed container 201 may be different from the polarity of the electrode tabs extending from the upper half (or lower half) of the other short side. For example, the polarities of the electrode tabs 202 and 204 may be different. Also, the polarities of the electrode tabs 203 and 205 may be different.

[0032] In one embodiment, the polarity of the electrode tab extending from the upper half (or lower half) of one short side of the sealed container 201 may be the same as the polarity of the electrode tab extending from the upper half (or lower half) of the other short side. For example, the polarities of the electrode tabs 202 and 204 may be the same. Also, the polarities of the electrode tabs 203 and 205 may be the same.

[0033] In one example, electrode tabs 202 and 205 are electrode tabs for a negative electrode, and electrode tabs 203 and 204 are electrode tabs for a positive electrode. In another example, electrode tabs 203 and 204 are electrode tabs for a negative electrode, and electrode tabs 202 and 205 are electrode tabs for a positive electrode. In another example, electrode tabs 202 and 204 are electrode tabs for a negative electrode, and electrode tabs 203 and 205 are electrode tabs for a positive electrode. In another example, electrode tabs 202 and 204 are electrode tabs for a positive electrode, and electrode tabs 203 and 205 are electrode tabs for a negative electrode.

[0034] In one embodiment, the electrode tab for the positive electrode may be made of at least one material selected from the group consisting of aluminum, titanium, stainless steel, nickel, and alloys thereof. In one embodiment, the electrode tab for the negative electrode may be made of at least one material selected from the group consisting of copper, nickel, titanium, iron, metals that do not react with lithium, and alloys thereof, and stainless steel (SUS).

[0035] <Compression Pad 21> Returning to FIG. 2 , the explanation continues. As shown in the figure, the compression pads 21 can be arranged on both sides of the cell stack 20 in the stacking direction (the x-axis direction in the example of FIG. 2 ). The compression pads 21 can be, for example, polyurethane foam, silicone foam, or acrylic foam. The compression pads 21 can function as a buffer material to protect the cells 200 from impact and vibration. The compression pads 21 can function to mitigate expansion and contraction of the cells 200 associated with charging and discharging, and to maintain a uniform internal pressure in the cell stack 20. In one embodiment, the compression pads 21 can also be arranged between the cells 200 of the cell stack 20. In this case, the compression pads 21 can function to delay or prevent a thermal chain reaction between the cells 200. For example, if a cell 200 in the cell stack 20 ignites, the compression pads 21 can prevent the heat caused by the ignition from being transmitted to other adjacent cells 200.

[0036] <Busbar Housing 22> The pair of busbar housings 22 includes a first busbar housing 22A and a second busbar housing 22B. The first busbar housing 22A and the second busbar housing 22B are arranged to sandwich the cell stack 20 on the side (y-axis direction) from which the electrode tabs of the cell stack 20 protrude. Electrode tabs 202 and 203 of the cells 200 protrude toward the first busbar housing 22A. Electrode tabs 204 and 205 of the cells 200 protrude toward the second busbar housing 22B. In the following description, when there is no need to distinguish between the first busbar housing 22A and the second busbar housing 22B, they are simply referred to as "busbar housings 22." The same applies to the other "pairs" of configurations of the cell stack 2.

[0037] The bus bar housing 22 accommodates multiple bus bars 220. The bus bar housing 22 is made of an insulating material such as resin. The bus bars 220 may be made of a conductive material such as copper, aluminum, nickel, or an alloy thereof. Electrode tabs (see "201-204" in FIG. 2B) protruding from the cells 200 are connected to the bus bars 220 by welding, for example. The number and polarity of the electrode tabs connected to each bus bar 220 can be set as appropriate, thereby defining the electrical connection relationship (series or parallel) between the cells 200. The bus bars 220 provided at the ends of the bus bar housing 22 are also called terminals and can be connected to bus bars 4 (see FIG. 1). The bus bars 4 electrically connect the cell stacks 2 to each other.

[0038] <Thermal Conductive Sheet 23> The pair of thermally conductive sheets 23 includes a first thermally conductive sheet 23A and a second thermally conductive sheet 23B. The first thermally conductive sheet 23A is disposed on the outer side of the first bus bar housing 22A (the side opposite the surface facing the cell stack 20) ​​so as to cover the bus bar 220. The second thermally conductive sheet 23B is disposed on the outer side of the second bus bar housing 22B (the side opposite the surface facing the cell stack 20) ​​so as to cover the bus bar 220. The thermally conductive sheet 23 may be formed, for example, by sandwiching a sheet of silicone between resin films (e.g., PET film). The thermally conductive sheet 23 is thermally conductive and insulating, ensuring heat transfer between the bus bar housing 22 and the gas control plate 24 while electrically insulating the bus bar 220 and the gas control plate 24. The thermally conductive sheet 23 may contribute to improving the cooling efficiency of the battery assembly 1.

[0039] <Gas Control Plates 24> The pair of gas control plates 24 includes a first gas control plate 24A and a second gas control plate 24B. The first gas control plate 24A is disposed opposite the first bus bar housing 22A via the first thermally conductive sheet 23A. The second gas control plate 24B is disposed opposite the second bus bar housing 22B via the second thermally conductive sheet 23B. The gas control plate 24 is configured to cover at least the side surface (the surface on which the bus bar 220 is provided) and the top surface of the bus bar housing 22. The gas control plate 24 may be made of a material with excellent thermal conductivity and flame resistance. The gas control plate 24 may be configured, for example, by bending a metal plate made of aluminum, nickel, copper, or the like into a generally L-shape.

[0040] The gas control plate 24 can function to guide gas discharged from the cell stack 20 downward in the cell stack 2. For example, if the internal temperature of some of the cells 200 constituting the cell stack 20 rises due to an abnormality such as a short circuit, gas may leak from the cell 200. The gas control plate 24 suppresses or prevents such gas from flowing upward or to the sides of the cell stack 2. The gas control plate 24 also guides the gas downward in the cell stack 2 (to a gas inlet 330 provided in the bottom plate 31 of the housing 3, which will be described later).

[0041] The cell stack 2 may be accommodated in the housing 3 such that the gas control plate 24 abuts against the side wall 30 of the housing 3. This may improve the cooling efficiency of the battery assembly 1. In one embodiment, a thermally conductive paste may be applied to the surface of the gas control plate 24 (the surface facing the side wall 30 of the housing) to increase adhesion between the gas control plate 24 and the side wall 30. This may improve the cooling efficiency of the battery assembly 1.

[0042] The insulating sheet 25 is provided to cover the cell stack 20. The insulating sheet 25 may be made of one or more resin sheets. The insulating sheet 25 may be made of, for example, polypropylene, polycarbonate, polyethylene, polyamide, polyethylene terephthalate, ABS, carbon reinforced plastic (CFRP), or a composite material thereof. The insulating sheet 25 may be disposed on a surface of the cell stack 20 other than the surface on which the bus bar housing 22 is provided. The insulating sheet 25 may be bonded to the cell stack 20 with an adhesive such as urethane or epoxy.

[0043] <Cell Stack Housing 26> The cell stack housing 26 is a housing made of, for example, metal or resin that houses the cell stack 20. The cell stack housing 26 is an example of a jig in the present disclosure. The cell stack housing 26 includes at least first and second side surfaces 26a, 26b (surfaces parallel to the yz plane) that cover both sides of the cell stack 20 in the stacking direction (x-axis direction) and a bottom surface 26c (surface parallel to the xy plane) that covers the lower surface of the cell stack 20. The first and second side surfaces 26a, 26b and the bottom surface 26c are plate-shaped members. The first and second side surfaces 26a, 26b face each other, and their lower ends are continuously connected to the bottom surface 26c. The cell stack housing 26 is configured such that the first and second side surfaces 26a, 26b are in close contact with one end and the other end of the cell stack 20 in the stacking direction, applying pressure to sandwich the cell stack 20 from both sides. At this time, pressure in the x-axis direction is also applied to the multiple cells 200. In other words, the cell stack 20 is housed in the cell stack housing 26 so that it is pressurized from the cell stack housing 26 via the insulating sheet 25 and the compression pad 21.

[0044] The cell stack housing 26 accommodates the cell stack 20 by applying pressure to sandwich the cell stack 20 from both sides. The applied pressure is 20 kPa or more and 350 kPa or less, preferably 50 kPa or more and 100 kPa or less. This not only improves the energy density of the battery assembly 1 but also makes it easier to attach the cell stack 2 to the housing 3 compared to attaching the cell stack 20 directly to the housing 3 (i.e., without first accommodating the cell stack 20 in the cell stack housing 26). The cell stack housing 26 also has a generally U-shaped vertical cross section along the stacking direction (x-axis direction) of the cell stack 20. This not only improves the ease of cell stack installation during battery pack manufacturing but also protects the side and bottom surfaces of the cell stack 20 in the stacking direction from external impacts. The shape of the cell stack housing 26 may be appropriately modified to match the shape of the cell stack 20. For example, the bottom surface 26c of the cell stack housing 26 may have a rounded or uneven shape.

[0045] As shown in FIG. 5 , the cell stack housing 26 includes a first connection portion 26d extending vertically from the upper end of the first side surface 26a. The cell stack housing 26 also includes a second connection portion 26e extending vertically from the upper end of the second side surface 26b. The first and second connection portions 26d and 26e extend in opposite directions outward relative to the cell stack 20. The cell stack housing 26 is configured to abut against the upper end of the housing 3 at the first and second connection portions 26d and 26e (note that for ease of explanation, the cell stack 20 and the like are not shown in FIG. 5 ). Holes 26f may be formed in the first and second connection portions 26d and 26e, respectively. The cell stack housing 26 may be fixed to the housing 3 by inserting a fastening member (e.g., bolt B) through the holes 26f. The holes 26f may be irregularly shaped holes having a major axis and a minor axis. For example, as shown in FIG. 5 , the hole 26f may have a major axis in the stacking direction of the cell stack 20. The major axis is larger than the nominal diameter of the bolt B. This allows the attachment position of the cell stack housing 26 to the housing 3 to be adjustable along the direction of the major axis (the x-axis direction). That is, the cell stack 2 may be loosely attached to the housing 3 via the cell stack housing 26. This may facilitate attachment of the cell stack housing 26 to the housing 3 even if the size of the cell stack housing 26 in the stacking direction changes due to individual differences in the cell stack 20 or the degree of expansion and contraction during attachment. The number, arrangement, and shape of the first and second connecting portions 26d, 26e and the hole 26f may be appropriately determined for the housing 3. For example, the hole 26f may be polygonal, circular, elliptical, or the like. Furthermore, for example, one of the hole 26f of the first and second connecting portions 26d, 26e may be an irregular-shaped hole, and the other hole 26f may be a circular hole.

[0046] [Configuration of Housing 3] An example of the configuration of the housing 3 will be described with reference to Figures 6 and 7. Figure 6 is a perspective view for explaining the example of the configuration of the housing 3. Figure 7 is an exploded perspective view for explaining the example of the configuration of the housing 3.

[0047] 6 and 7 , the housing 3 includes a side wall 30 and a bottom plate 31 disposed below the side wall 30. The side wall 30 also includes a receiving hole 36 for connection to the cell stack housing 26. A fixing bolt B is passed through the hole 26f and the receiving hole 36 and fixed to the housing 3. The housing 3 is configured to protect the cell stack 2 from external impacts and the like. The housing 3 is also configured to release heat generated in the cell stack 2 to the outside. The housing 3 may be made of a material with high rigidity and thermal conductivity. For example, the housing 3 may be made of a metal material such as aluminum.

[0048] The housing 3 may be configured to accommodate multiple cell stacks 2 aligned along a horizontal plane (xy plane). In this case, the side walls 30 may be arranged in a grid pattern in a plan view (when the housing 3 is viewed from the positive direction of the z axis) to separate the space in which the multiple cell stacks 2 are arranged. For example, as shown in FIG. 7 , the side walls 30 may be configured with a first side wall portion 301 to a fourth side wall portion 304 extending along the x axis direction and a fifth side wall portion 305 to a seventh side wall portion 307 extending along the y axis direction, arranged in a grid pattern. Each side wall portion defines an accommodation space for accommodating the cell stacks 2. In this case, a receiving hole 36 is also provided in the sixth side wall portion 306.

[0049] For example, the storage space SP1 is defined by a space partitioned by the first side wall portion 301 and the second side wall portion 302, and the fifth side wall portion 305 and the sixth side wall portion 306. The distance between each side wall portion is set according to the shape of the cell stack 2 to be stored. For example, the distances between the first side wall portion 301 to the fourth side wall portion 304 can be set so that the cell stack 2 abuts against these side wall portions.

[0050] <Refrigerant Flow Channel 32> The side wall 30 has a refrigerant flow channel 32 through which a refrigerant FL flows to cool the cell stack 2. The refrigerant FL may be a liquid refrigerant (e.g., water, water-glycol liquid, oil, etc.) or a gaseous refrigerant (e.g., a refrigerant for air conditioners such as HFO-1234yf or HFC-134a). A refrigerant inlet 308 for introducing the refrigerant into the refrigerant flow channel 32 and a refrigerant outlet 309 for discharging the refrigerant from the refrigerant flow channel 32 are provided in a first side wall portion 301 of the side wall 30.

[0051] <Gas exhaust path 33> The bottom plate 31 may be configured as a plate-like body that covers from below the space defined by the side wall 30. The bottom plate 31 includes a gas exhaust path 33 for exhausting gas from the cell stack 2. The gas exhaust path 33 is configured from a gas inlet 330 and a gas flow path 331.

[0052] 6 and 7, the gas inlet 330 is provided on the inner surface of the bottom plate 31 (the surface facing the cell stack 2). A plurality of gas inlets 330 may be provided. The plurality of gas inlets 330 may be provided in rows along the stacking direction (x-axis direction) of the cell stack 20 of the cell stack 2. For example, as shown in FIG. 7, for one storage space SP1, a first row L1 consisting of a plurality of gas inlets 330 and a second row L2 consisting of a plurality of gas inlets 330 may be configured. The first row L1 and the second row L2 are parallel to each other.

[0053] Furthermore, a plurality of gas flow paths 331 may be provided. The plurality of gas flow paths 331 may be configured such that the cross-sectional shape of adjacent gas flow paths 331 is an upside-down triangle. In this case, the cross-sectional shape of the bottom plate 31 has a truss structure. This makes it possible to ensure the strength of the bottom plate 31 even when a plurality of gas flow paths 331 are provided inside the bottom plate 31.

[0054] As described above, the battery assembly 1 can maintain the pressure that the cell stack 2 receives within a more appropriate range, thereby improving the energy density of the battery assembly 1.

[0055] [Vehicle M Equipped with Battery Assembly 1] Figure 8 is a schematic diagram showing an example of a vehicle M equipped with a battery assembly 1. The vehicle M is an electric vehicle. The vehicle M includes the battery assembly 1 disposed on, for example, the floor of the vehicle body, a motor MT driven by power from the battery assembly 1, a PCU that controls the operation of both, and an exhaust system VS. The exhaust system VS is connected to a gas exhaust passage 33 of the housing 3 of the battery assembly 1 and is configured to exhaust gas from the battery assembly 1 to the outside of the vehicle M.

[0056] In one embodiment, the battery assembly 1 can be applied not only to electric vehicles, but also to vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (P-HEVs), electric motorcycles, and electric bicycles, as well as various mobile objects (drones, robots, power tools, ships, airplanes, etc.) and stationary systems.

[0057] [Additional Notes] The embodiments of the present disclosure further include the following aspects.

[0058] (Supplementary Note 1) A cell stack comprising: a pair of bus bar housings extending along a horizontal direction; a cell stack disposed between the pair of bus bar housings, the cell stack including a plurality of cells stacked along the horizontal direction, each of the plurality of cells having two or more electrode tabs protruding toward one of the pair of bus bar housings and two or more electrode tabs protruding toward the other of the pair of bus bar housings; and a jig configured to sandwich the cell stack from both sides and apply a pressure of 20 kPa to 350 kPa in the horizontal direction to the plurality of cells, the jig having a first side surface, a second side surface opposing the first side surface, and a bottom surface extending along the horizontal direction from a lower end of the first side surface to a lower end of the second side surface.

[0059] (Supplementary Note 2) The cell stack according to Supplementary Note 1, wherein the jig has a substantially U-shaped vertical cross section along the horizontal direction.

[0060] (Supplementary Note 3) The cell stack according to Supplementary Note 1 or 2, wherein each of the cells includes a sealed container that houses an electrode stack, and the sealed container is a substantially rectangular bag having a pair of short sides and a pair of long sides.

[0061] (Supplementary Note 4) The cell stack according to Supplementary Note 3, wherein each of the cells is arranged in the cell stack such that a pair of short sides of the sealed container extend in a vertical direction.

[0062] (Supplementary Note 5) The cell stack according to Supplementary Note 4, wherein the polarity of the electrode tab drawn from the upper half of one short side of the sealed container is different from the polarity of the electrode tab drawn from the upper half of the other short side of the sealed container.

[0063] (Supplementary Note 6) The cell stack according to Supplementary Note 3, wherein the electrode laminate includes a current collector having a resin layer and a pair of conductive layers provided on both sides of the resin layer.

[0064] (Supplementary Note 7) A battery assembly comprising at least one cell stack according to any one of Supplementary Notes 1 to 6, and a housing that accommodates the cell stack.

[0065] (Appendix 8) The battery assembly described in Appendix 7, wherein the jig includes a first connection portion extending from an upper end of the first side surface and a second connection portion extending from an upper end of the second side surface, and the cell stack is configured to be fixed to the housing by coupling the first connection portion and the second connection portion to the housing with fastening members.

[0066] (Supplementary Note 9) The battery assembly according to Supplementary Note 8, wherein at least one of the first connection portion and the second connection portion has a hole portion into which the fastening member is inserted, the hole portion having a diameter in the horizontal direction larger than a nominal diameter of the fastening member.

[0067] (Supplementary Note 10) A vehicle comprising: the battery assembly according to any one of Supplementary Notes 7 to 9; and a motor supplied with power from the battery assembly.

[0068] The above embodiments are described for the purpose of explanation and are not intended to limit the scope of the present disclosure. Various modifications can be made to the above embodiments without departing from the scope and spirit of the present disclosure. For example, some components in one embodiment can be added to other embodiments. Also, some components in one embodiment can be replaced with corresponding components in other embodiments.

[0069] REFERENCE SIGNS LIST 1...battery assembly, 2...cell stack, 20...cell laminate, 200...cell, 201...sealed container, 202-205...electrode tabs, 21...compression pad, 22...bus bar housing, 23...thermal conductive sheet, 24...gas control plate, 25...insulating sheet, 26...cell stack housing, 26a, b...first and second side surfaces, 26c...bottom surface, 26d, e...first and second connection portions, 26f...hole portion, 3...housing, 30...side wall, 31...bottom plate, 32...refrigerant flow path, 33...gas exhaust path, 36...receiving hole, 330...gas inlet, 331...gas flow path, 4...bus bar, B...bolt, M...vehicle

Claims

1. A cell stack comprising: a pair of bus bar housings extending along a horizontal direction; a cell stack disposed between the pair of bus bar housings, the cell stack including a plurality of cells stacked along the horizontal direction, each of the plurality of cells having two or more electrode tabs protruding toward one of the pair of bus bar housings and two or more electrode tabs protruding toward the other of the pair of bus bar housings; and a jig configured to sandwich the cell stack from both sides and apply a pressure of 20 kPa to 350 kPa in the horizontal direction to the plurality of cells, the jig having a first side surface, a second side surface opposing the first side surface, and a bottom surface extending along the horizontal direction from the lower end of the first side surface to the lower end of the second side surface.

2. The cell stack according to claim 1, wherein the jig has a vertical cross section along the horizontal direction that is approximately U-shaped.

3. The cell stack according to claim 1, wherein each of the cells includes a sealed container that houses an electrode stack, and the sealed container is a substantially rectangular bag having a pair of short sides and a pair of long sides.

4. The cell stack according to claim 3, wherein each of the cells is arranged in the cell stack so that the direction in which a pair of short sides of the sealed container extend is vertically up and down.

5. The cell stack according to claim 4, wherein the polarity of the electrode tab drawn from the upper half of one short side of the sealed container is different from the polarity of the electrode tab drawn from the upper half of the other short side of the sealed container.

6. The cell stack according to claim 3, wherein the electrode laminate comprises a current collector having a resin layer and a pair of conductive layers provided on both sides of the resin layer.

7. A battery assembly comprising at least one cell stack according to claim 1 and a housing for accommodating said cell stack.

8. The battery assembly described in claim 7, wherein the jig has a first connection portion extending from an upper end of the first side surface and a second connection portion extending from an upper end of the second side surface, and the cell stack is configured to be fixed to the housing by coupling the first connection portion and the second connection portion to the housing with fastening members.

9. A battery assembly as described in claim 8, wherein at least one of the first connection portion and the second connection portion has a hole portion into which the fastening member is inserted, the hole portion having a horizontal diameter larger than the nominal diameter of the fastening member.

10. A vehicle comprising: a battery assembly according to claim 7; and a motor supplied with power from said battery assembly.

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