Battery module and battery pack including same

Abstract

In the present invention, pressure is uniformly applied to a laminated electrode body of battery cells. A battery module (110) comprises a fixing plate (104) for pressurizing a plurality of battery cells (1) from the lamination direction. The fixing plate (104) is fixed to a bracket (210) on a housing side as a result of a fixing boss (144) at both ends of the fixing plate being fixed to the bracket by a fixing bolt (220). An axial line (CL) of the fixing boss (144) is orthogonal to the lamination direction of the laminated electrode body (10) of the battery cells (1), a fastening point (CP) of the fixing boss (144) is outside a projection surface of the laminated electrode body (10) as seen from the lamination direction, and a pressure surface (141m) of the fixing plate (104) presses the entire surface of the laminated electrode body (10).

Description

Battery module and battery pack including same

[0001] The present invention relates to a battery module formed by stacking a plurality of battery cells whose thickness changes with charge and discharge, and in particular to a pressurization technique for a battery module suitable for lithium deposition-type all-solid-state batteries.

[0002] In this type of battery module, the thickness of the stacked electrode body of each battery cell changes in the stacking direction as the battery module is charged and discharged. Therefore, to ensure that the battery module consistently achieves the desired performance despite changes in battery cell thickness due to charging and discharging, a pressure mechanism is provided that applies pressure to the stacked battery cells (see, for example, Patent Document 1). The pressure mechanism described in Patent Document 1 includes a pair of pressure plates disposed on both ends of the stacked battery cells. One of the pair of pressure plates is fastened to a bracket on the housing side using a fixing bolt in a direction perpendicular to the pressure surface of the pressure plate.

[0003] Japanese Patent Application Laid-Open No. 2019-147547

[0004] However, in the technology described in Patent Document 1, the fixing bolts are positioned so as to overlap the stacked electrode body of the battery cell when viewed in plan (i.e., so as to overlap the projected surface of the stacked electrode body when viewed from the stacking direction). Therefore, the pressure applied by the pressure mechanism to the stacked electrode body by the pressure mechanism is relatively higher at and near the location of the fixing bolts on the pressure surface of the pressure plate than in other areas. Furthermore, the pressure applied by the pressure mechanism to the stacked electrode body by the pressure mechanism is relatively lower in other areas. Therefore, the technology described in Patent Document 1 still has room for improvement in terms of applying a uniform pressure to the stacked electrode body of the battery cell.

[0005] Therefore, the present invention has been made in light of these problems, and an object of the present invention is to provide a battery module that can apply a uniform pressure force to the stacked electrode body of the battery cells, and a battery pack that includes the same.

[0006] In order to solve the above problem, a battery module according to one aspect of the present invention includes battery cells whose thickness in the stacking direction of a laminated electrode body changes due to charging and discharging, the battery module being formed by stacking a plurality of the battery cells in the stacking direction, and a fixing plate having a pressure surface that is arranged at an end of the stacked plurality of battery cells and applies pressure to the plurality of battery cells from the stacking direction, the fixing plate being fixed to a bracket for mounting the battery module on a vehicle with fixing bolts, the fixing plate having fixing bosses at its ends and with columnar fastening holes, and the fixing plate being fixed to the bracket with fixing bolts that are inserted into the fastening holes of the fixing bosses, the axes of the fastening holes of the fixing bosses being perpendicular to the stacking direction of the laminated electrode body, the opening faces of the fastening holes of the fixing bosses being located outside the projected surface of the laminated electrode body when viewed from the stacking direction, and the pressure surface of the fixing plate applying pressure to the entire surface of the laminated electrode body of the battery cell.

[0007] In addition, in order to solve the above problem, a battery pack according to one aspect of the present invention is a battery pack that is mounted on a vehicle while being housed in a rectangular storage case, and includes a battery module housed in the storage case, and the battery module includes a battery module according to one aspect of the present invention.

[0008] According to the present invention, a uniform pressure can be applied to the stacked electrode assembly of the battery cell.

[0009] 1 is an explanatory diagram of an embodiment of a battery pack including a battery module according to an aspect of the present invention, in which (a) is a perspective view of the battery pack seen from diagonally above the housing case with the case cover removed, and (b) is a Z-Z cross-sectional view of (a) in FIG. 1. FIG. 2 is a schematic explanatory diagram of an all-solid-state battery that is an embodiment of a battery module according to an aspect of the present invention. FIG. 3 is an explanatory diagram of an embodiment of a battery cell that constitutes a battery module according to an aspect of the present invention, in which the diagram shows a schematic cross-sectional view along the thickness direction of a cell that constitutes a laminated electrode body. FIG. 4 is an explanatory diagram of an embodiment of a fixing plate that constitutes a pressure mechanism of a battery module according to an aspect of the present invention, in which (a) is a perspective view seen from above the rear side, (b) is a side view, and (c) is a plan view seen from the rear side. 2(a) and 2(b) are explanatory views of the fixing structure of the fixing plate of the embodiment, showing the state in which the fixing plate is fixed with fixing bolts to a bracket for mounting the battery module of the embodiment on a vehicle (FIG. 2(a) is an enlarged view of the main part of FIG. 2(b), (b) is a plan view of (a), and (c) is a left side view of (a)). FIG. 2(a) and 2(b) are explanatory views of the effect of the fixing bosses of the fixing plate, with (a) being an example when the battery cells are short, and (b) being an example when the battery cells are long. FIG. 2(a) and 2(b) are explanatory views of a modified example (first modified example) of the fixing plate of the embodiment, showing figures corresponding to FIGS. 4(b) and 4(c) respectively. FIG. 2(a) and 2(b) are explanatory views of a modified example (second modified example) of the fixing plate of the embodiment, showing a figure corresponding to FIG. 4(b) (battery cells not shown). 9(a) and 9(b) are explanatory views of a modified example (third modified example) of the embodiment, where FIG. 9(a) corresponds to FIG. 4(b) (battery cells are not shown), and FIG. 9(b) shows a Z-Z cross section of FIG. 9(a). FIGS. 9(a) and 9(b) are explanatory views of a modified example (fourth modified example) of the embodiment, where each view corresponds to FIG. 9. FIGS. 9(a) and 9(b) are explanatory views of a modified example (fifth modified example) of the embodiment, where each view corresponds to FIG. 4(b) (battery cells are not shown). FIGS. 9(a) and 9(b) are explanatory views of a modified example (sixth modified example) of the embodiment, where each view corresponds to FIG. 4(a) and FIG. 4(c). FIGS. 9(a) and 9(b) are explanatory views of a modified example (seventh modified example) of the embodiment, where each view corresponds to FIG. 4(a) and FIG. 4(c).

[0010] A battery module according to one embodiment of the present invention will be described below with reference to the drawings. The all-solid-state battery employed in the battery module of this embodiment is a secondary battery capable of being charged and discharged multiple times. The battery module of this embodiment is mounted, for example, as a battery pack in a vehicle. The vehicle of this embodiment is, for example, an electric vehicle, which is equipped with a charging path from an external power source and configured to receive power from the charging path and store electricity in the battery pack of this embodiment via a charger that charges the battery. The battery pack of this embodiment is disposed, for example, under the floor of a seat in the vehicle. Note that the drawings are schematic. Therefore, it should be noted that the relationship between thickness and planar dimensions, ratios, etc., differ from the actual ones, and the dimensional relationships and ratios differ between the drawings. Furthermore, the embodiments described below are intended to exemplify devices and methods embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the following embodiments in terms of the materials, shapes, structures, arrangements, etc. of the components.

[0011] [Battery Pack] The battery pack of this embodiment will be described with reference to Fig. 1. As shown in Fig. 1(a), the battery pack 100 of this embodiment is mounted on a vehicle while housed in a rectangular parallelepiped housing case 200. The upper opening of the housing case 200 is covered by a case cover (not shown). In the example shown in Fig. 1(a), two sets of battery modules 110R, 110L are housed symmetrically in the center of the housing case 200 in the front-to-rear direction (which coincides with the front-to-rear direction of the vehicle). Spaces necessary for housing auxiliary equipment, including a battery control unit, are provided in front of and behind the two sets of battery modules 110R, 110L within the housing case 200.

[0012] The battery pack 100 of this embodiment has a bottom plate 106 on the underside of the vehicle and an upper plate 107 disposed above the bottom plate 106 and spaced apart from each other. A storage compartment is provided in the space between the bottom plate 106 and the upper plate 107 to store left and right battery modules 110R, 110L. In each battery module 110R, 110L, a plurality of battery cells 1 are stacked vertically within the storage compartment of the battery pack 100 in the installation position shown in the figure. Note that the left and right battery modules 110R, 110L have a symmetrical structure, and therefore will be referred to below as the representative reference numeral 110 unless otherwise distinguished.

[0013] In a battery module 110 employing Li-precipitation-type all-solid-state batteries as battery cells 1, the multiple battery cells 1 expand and contract in the stacked expansion and contraction direction in response to charge and discharge. Therefore, a uniform pressure of at least a predetermined level must be maintained regardless of the charge and discharge state. In contrast, the battery pack 100 of this embodiment is provided with a pressure mechanism attached to each battery module 110. The pressure mechanism has guide shells 103 that can restrain the multiple battery cells 1 along the extension direction of the bottom plate 106 and the top plate 107, and supports the stacked position, enabling smooth movement of the multiple battery cells 1 in the stacking direction.

[0014] [Battery Module] Next, the battery module of this embodiment will be described with reference to FIG. 2 . As shown in the schematic diagram of FIG. 2 , in a battery module 110 of this embodiment, ends of the battery cells 1 are fixed to a fixing plate 104 in the stacking direction. The fixing plate 104 is provided with a connection terminal 101 that is electrically connected to an external device (not shown). In the battery module 110 of this embodiment, the positive and negative electrode tab leads 31, 32 of each battery cell 1 are arranged so that they extend laterally from the center of one side and the other opposite side. The tab leads 31, 32 of adjacent battery cells 1 are connected to each other via a bus bar 40 by welding or the like.

[0015] Additionally, the positive electrode tab leads 31 and negative electrode tab leads 32 located at both ends of the stacked battery cells 1 are disposed opposite the connection terminals 101 and are electrically connected to the connection terminals 101 via bus bars 40. In the battery module 110 of this embodiment, the positive electrode and negative electrode tab leads 31, 32 of adjacent battery cells 1 are connected to each other via the bus bars 40 in this manner, so that the entire plurality of battery cells 1, 1 are electrically connected in series.

[0016] In the battery module 110 of this embodiment, the fixing plate 104 is fixed to a bracket 210 on the accommodating case 200 side by a fixing bolt 220. The stacked battery cells 1 are held in a stacked state between the bottom plate 106 and the top plate 107 by the fixing plate 104, and are pressurized by a pressure mechanism (not shown). When the battery cells 1 expand and contract, the stacked battery cells 1 can slide together with the guide shell 103 in response to the expansion and contraction of the battery cells 1.

[0017] [Battery Cell] Next, the structure of the battery cell 1 will be described with reference to FIG. 3 . The battery cell 1 of this embodiment is formed to have a substantially rectangular shape in a plan view. Note that the electrode structure of the battery cell 1 shown in the figure is a so-called non-bipolar type (internal parallel connection type), but it may also be a bipolar type (internal series connection type). Furthermore, the shape of the battery cell 1 is not limited to a rectangular shape and may be a circular or elliptical shape, for example. As shown in the figure, the battery cell 1 of this embodiment has a laminated electrode body 10 as a power generation element, in which a positive electrode current collector 11, a positive electrode layer 13, a solid electrolyte layer 14, a negative electrode layer 15, and a negative electrode current collector 12 are laminated.

[0018] The laminated electrode assembly 10 is covered by a laminate film 20 including a pair of outer casings 21, 22 sandwiched between both sides in the thickness direction. The laminate film 20 includes a metal foil layer and a resin layer. In this embodiment, the laminate film 20 is integrally formed by sandwiching the metal foil layer between front and back resin layers. The positive electrode current collector 11 and the negative electrode current collector 12 are formed in the shape of rectangular thin plates using a metal material such as aluminum, nickel, iron, stainless steel, titanium, or copper. The positive electrode current collector 11 and the negative electrode current collector 12 each have a flexible lead electrode 11p, 12p extending laterally from one side forming the outer edge. Positive and negative electrode tab leads 31, 32 are attached to the tips of the lead electrodes 11p, 12p, respectively, as terminals.

[0019] The positive electrode layer 13 is disposed on both main surfaces of the positive electrode current collector 11 (at the end, only on the main surface of the positive electrode current collector 11 facing the negative electrode current collector 12). The positive electrode layer 13 is configured to contain, as a positive electrode active material, a substance that utilizes an oxidation-reduction reaction to release lithium ions during charging and to absorb lithium ions during discharging. Examples of materials for the positive electrode active material include lithium-transition metal composite oxides such as LiMn2O4, LiCoO2, LiNiO2, and Li(Ni-Mn-Co)O2, as well as lithium-transition metal phosphate compounds and lithium-transition metal sulfate compounds, such as those in which part of the transition metal in these oxides is substituted with other elements.

[0020] The solid electrolyte layer 14 contains a solid electrolyte as a main component and is a layer interposed between the positive electrode layer 13 and the negative electrode layer 15. Examples of solid electrolyte materials include sulfide solid electrolytes and oxide solid electrolytes, with sulfide solid electrolytes being preferred. Suitable sulfide solid electrolytes include LPS-based materials (e.g., argyrodite (LiPSCl)) and LGPS-based materials (e.g., LiGePSS).

[0021] The anode layer 15 is disposed on both main surfaces of the anode current collector 12 (only on the surface of the anode current collector 12 facing the cathode current collector 11 at the end). The anode layer 15 is configured to contain at least lithium metal or a substance that forms an alloy with lithium as anode active material. "Containing lithium metal as the anode active material in the anode layer 15" includes cases where lithium metal foil or lithium metal particles are disposed on the main surface of the anode current collector 12, and cases where lithium metal is deposited on the main surface of the anode current collector 12 using a cathode that includes a cathode active material such as a lithium-transition metal composite oxide, a lithium-transition metal phosphate compound, or a lithium-transition metal sulfate compound. "Containing a substance that forms an alloy with lithium as an active material in the anode layer 15" means that the anode layer 15 contains at least one substance selected from the group consisting of In, Al, Si, and Sn.

[0022] In the battery module 110 of this embodiment, the positive and negative electrode tab leads 31, 32 of each battery cell 1 are provided on the center line in the thickness direction of the battery cell 1, protruding laterally from one side and the other side on the opposite side along the center line. The joints 23 of the exterior body 20 are sealed without gaps with an insulating sealant. When there is no need to distinguish between the positive and negative electrode tab leads 31, 32, they will simply be referred to as tab leads 30.

[0023] [Fixing Plate of Pressurizing Mechanism] Next, the fixing plate constituting the pressing mechanism of this embodiment will be described in detail. As described above, the battery pack 100 of this embodiment is configured to contain at least lithium metal or a material that forms an alloy with lithium as the negative electrode active material. Therefore, the stacked battery cells 1, 1... of each battery module 110 expand and contract in the stacking direction as lithium ions are absorbed and released during charging and discharging. In contrast, as shown in FIG. 1(b), the battery module 110 of this embodiment includes a pressing mechanism that pressurizes the stacked battery cells 1 in order to stably exhibit the desired performance of the battery module 110 in response to changes in the thickness of the battery cells 1 that occur during charging and discharging.

[0024] The pressure mechanism is arranged to be able to apply pressure to the stacked battery cells 1 toward the fixing plate 104, as shown in the expansion / contraction direction in FIG. 1( b). The fixing plate 104 is fixed by fixing bolts 220 to a bracket 210 on the side of a housing 200 for mounting the battery module 110 in a vehicle. As shown in FIG. 4, the fixing plate 104 has two columnar fixing bosses 144 provided on both left and right ends of the fixing plate 104, with the axis CL of the fastening hole perpendicular to the stacking direction of the laminated electrode body 10. A fixing bolt 220 is attached to each fixing boss 144 of the fixing plate 104, and the fixing plate 104 is fixed to the bracket 210 by the two fixing bolts 220. Note that in this embodiment, the positions of the fixing bosses 144 are asymmetrical above and below the bracket 210. In this embodiment, the upper recessed portion 144u is longer in the axial direction, and the lower recessed portion 144s is shorter in the axial direction than the upper recessed portion 144u.

[0025] In the battery module 110 of this embodiment, the axis CL of the fastening hole of each fixing boss 144 is perpendicular to the stacking direction of the laminated electrode body 10, the fastening point CP of each fixing boss 144 is located outside the projection surface 10M of the laminated electrode body 10 when viewed from the stacking direction, and the pressure surface 141m of the fixing plate 104 applies pressure to the entire surface (projection surface 10M) of the laminated electrode body 10 of the battery cell 1. Here, in this specification, the area of ​​the projection surface 10M of the laminated electrode body 10 when viewed from the stacking direction is the capacity performance guarantee area (area requiring uniform pressure).

[0026] Furthermore, as shown in Figures 4 and 5, the fixed plate 104 has a hollow portion 146 on the back side of the pressure surface 141m. In this embodiment, the fixed plate 104 has a configuration including a pressure side plate 141 including the pressure surface 141m, left and right protruding plates 142 protruding from the back side of the pressure side plate 141, and a back side plate 143 provided at the tip of the protruding plate 142 via the hollow portion 146 on the back side of the pressure side plate 141, thereby defining a double-structure hollow portion 146. Also, in this embodiment, as shown in Figures 4 and 5, the hollow portion 146 is a single hole extending from the entire space between the pressure side plate 141 and the back side plate 143. This prevents localized increases in rigidity at the rib portions, as would occur when a rib portion is provided, thereby enabling a uniform rigidity distribution and a uniform surface pressure distribution.

[0027] [Effects] Next, the effects of the battery module 110 of this embodiment will be described. When the thickness of the battery cells 1 changes during charging and discharging, as in the battery module 110 of this embodiment, the battery module 110 needs to be pressurized with a uniform surface pressure distribution using a pressurizing mechanism in order to stably achieve the desired performance. In contrast, in the battery module 110 of this embodiment, as shown in FIGS. 4 and 5 , the axis CL of the fastening hole of each fixing boss 144 provided on the left and right sides of the fixing plate 104 is perpendicular to the stacking direction of the laminated electrode body 10, and the fastening point CP of each fixing boss 144 is located outside the projection surface 10M of the laminated electrode body 10 as viewed from the stacking direction, so that the pressure surface 141m of the fixing plate 104 presses the entire surface (projection surface 10M) of the laminated electrode body 10 of the battery cells 1.

[0028] As a result, in the battery module 110 of this embodiment, the fastening points CP (centers of the fastening holes 145 of the fixing bosses 144) of the fixing bolts 220 are located outside the stacked electrode bodies 10 of the battery cells 1, thereby uniforming the rigidity of the back surface of the stacked electrode bodies 10 of the battery cells 1. Furthermore, because the fixing points are columnar fixing bosses 144 rather than plates, the rigidity of the back surface of the stacked electrode body 10 is further improved, and the torsional strength of the pressure surface 141m is improved, preventing or suppressing damage to the battery cells 1 due to stress concentration. This allows for uniform pressure to be applied to the stacked electrode bodies 10 of the battery cells 1 [Invention 1].

[0029] 1, the battery pack 100 of this embodiment is mounted on a vehicle housed in a rectangular parallelepiped housing case 200, and the battery module 110 of this embodiment is housed within the housing case 200. This allows the battery pack 100 to be mounted on a vehicle while maintaining uniform rigidity of the stacked electrode body of the battery cells. Also, the distribution of surface pressure applied to the stacked electrode body of the battery cells can be made uniform [Invention 9].

[0030] Furthermore, in the battery module 110 of this embodiment, as shown in Figures 4 and 5, the fixing plate 104 has a double-structure hollow portion 146 on the back side of the pressure surface 141m. This allows for weight reduction by removing excess material while maintaining the function of uniformly distributing surface pressure, which is advantageous for improving power consumption [Invention 2].

[0031] Furthermore, in the battery module 110 of this embodiment, as shown in Figures 4 and 5, the hollow portion 146 is a single hole, which is advantageous in avoiding locally high rigidity in the rib portion, and in achieving a uniform rigidity distribution and a uniform surface pressure distribution [Invention 3].

[0032] In the battery module 110 of this embodiment, the positions of the fixing bosses 144 are asymmetrical from top to bottom, as shown in Figures 4 and 5, resulting in a structure that is excellent for vehicle mountability. In other words, as shown in Figure 6 (a), if the positions of the fixing bosses 144 were symmetrical from top to bottom, and the height of the fixing bosses 144 was to be limited by the floor height when the battery module was mounted on the vehicle, a wasted area (indicated by the arrow in Figure 6) would be created on the floor side, and the range for arranging the battery cells 1 would be narrowed. On the other hand, if battery cells 1 equivalent to those in the battery module 110 of this embodiment were to be arranged, a protruding area (indicated by the arrow in Figure 6) would be created above the floor, as shown in Figure 6 (b), resulting in a higher floor height and a narrower vehicle interior.

[0033] As described above, the battery module 110 of this embodiment and the battery pack 100 including the same can uniformly distribute the surface pressure on the stacked electrode body 10 of the battery cell 1. The battery module and the battery pack including the same according to the present invention are not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0034] For example, in the battery module 110 of this embodiment, as shown in a first modification in Fig. 7, the fixing plate 104 may be formed from a single block 140 in the shape of a direct storage body without providing the hollow portion 146. However, in order to reduce weight and improve power efficiency by removing excess material while maintaining the function of uniformly distributing surface pressure, it is desirable to provide the double-structure hollow portion 146 as in the above embodiment.

[0035] Furthermore, in the above embodiment, the hollow portion 146 is formed by a single hole, but this is not limiting. For example, in the battery module 110 of this embodiment, as shown in a second modification in FIG. 8 , the hollow portion 146 can be configured by dividing the space defined by the pressure side plate 141, the protruding plate 142, and the rear side plate 143 into multiple regions. In the example shown in the same figure, a partition plate 147 consisting of vertical partition plates 147h and horizontal partition plates 147u can be provided to divide the defined space into a grid pattern. This configuration can reduce variations in rigidity in parts by anticipating deformation of the pressure surface 141m due to pressure, which is advantageous for achieving a more uniform surface pressure distribution on the pressure surface.

[0036] 9 shows a third modification of the battery module 110 of this embodiment. The hollow portion 146 can be formed with a convex spherical surface 141r on the cell-side rear surface. This configuration increases the rigidity of the center of the pressure-applying surface 141m of the pressure-applying side plate 141, which is prone to deformation under load. This configuration is therefore suitable for achieving a more uniform surface pressure distribution on the pressure-applying surface 141m [Invention 4].

[0037] 10 shows a fourth modification of the battery module 110 of the present embodiment, the hollow portion 146 may be provided with a plurality of radial ribs 147r connecting the cell-side rear surface and the surface facing it as the partition plate 147. This configuration allows for deformation of the pressure-applied surface 141m due to pressure and partially reduces variations in the rigidity of the pressure-applied side plate 141, which is advantageous for making the surface pressure distribution on the pressure-applied surface 141m more uniform [Invention 5].

[0038] 11 shows a fifth modification of the battery module 110 of the present embodiment, the hollow portion 146 can be filled with an elastic body 148. With such a configuration, the elastic body 148 filled in the hollow portion 146 can absorb variations in the surface pressure due to pressure on the pressure application surface 141m, which is preferable for making the surface pressure distribution on the pressure application surface 141m more uniform [Invention 6].

[0039] 12 shows a sixth modification of the battery module 110 of this embodiment, a through-hole 149 can be formed in the stacking direction in the outer rear side plate 143 that defines the hollow portion 146. This configuration ensures the rigidity required for the fixing plate 104, while reducing the weight by removing excess material, which is advantageous for improving power consumption [Invention 7].

[0040] In the battery module 110 of this embodiment, as shown in a seventh modification in FIG. 13 , the through-hole 149 is not limited to one location, but can be formed in multiple locations, as long as the rigidity required for the fixing plate 104 is ensured. Furthermore, the opening shape of the through-hole 149 is not limited to a circular shape, and various opening shapes are possible. Furthermore, the through-hole is not limited to a through-hole, and a counterbore hole may be used for the purpose of reducing the thickness. In consideration of the heat dissipation properties for the heat generated by the battery cell 1, a counterbore hole is preferable in order to increase the surface area. Furthermore, a through-hole is preferable if weight reduction is the main focus.

[0041] In particular, in the battery module 110 of this embodiment, it is desirable that the rigidity of the fixing plate 104 be greater than the overall rigidity of the plurality of battery cells 1. With this configuration, in an all-solid-state battery, the input load from the battery cell 1 side is greater than in conventional batteries, so the fixing plate 104 and the bracket 210 that supports it require even greater rigidity. This is therefore suitable for meeting strict quality requirements regarding variations in the surface pressure distribution of the stacked electrode body 10 [Invention 8].

[0042] REFERENCE SIGNS LIST 1 Battery cell 10 Laminated electrode body 11 Positive electrode current collector 11p, 12p Lead electrode 12 Negative electrode current collector 13 Positive electrode layer 14 Solid electrolyte layer 15 Negative electrode layer 20 Exterior body (laminated film) 21, 22 Exterior body 23 Joint 30 Tab lead 31, 32 Tab lead 40 Bus bar 100 Battery pack (all-solid-state battery) 101 Connection terminal 103 Guide shell 104 Fixing plate (pressure plate) 106 Bottom plate 107 Upper plate 110 Battery module 110R, 110L Battery module 140 Block 141 Pressurizing side plate 141m Pressurizing surface 141r Rear surface 142 Protruding plate 143 Rear side plate 144 Fixing boss 145 Fastening hole 146 Hollow portion 147 Partition plate 148 Elastic body 149 Through hole 200 Storage case 210 Bracket 220 Fixing bolt CL Axis of fastening hole CP Fastening point

Claims

1. A battery module comprising a plurality of battery cells stacked in the stacking direction, the thickness of which changes with charge and discharge in a stacked electrode body, the battery cell being stacked in the stacking direction; and a fixing plate having a pressure surface arranged at an end of the stacked battery cells and applying pressure to the plurality of battery cells in the stacking direction, the fixing plate being fixed to a bracket for mounting the battery module on a vehicle with fixing bolts, the fixing plate having fixing bosses at its end with pillar-shaped fastening holes, and the fixing plate being fixed to the bracket with fixing bolts inserted into the fastening holes of the fixing bosses, the axis of the fastening holes of the fixing boss being perpendicular to the stacking direction of the stacked electrode body, and the opening surface of the fastening hole of the fixing boss being located outside the projected surface of the stacked electrode body when viewed from the stacking direction, the battery module characterized in that the pressure surface of the fixing plate applies pressure to the entire surface of the stacked electrode body of the battery cell.

2. The battery module according to claim 1, wherein the fixing plate has a pressure side plate including the pressure surface, and a back side plate provided on the back side of the pressure side plate with a hollow portion interposed therebetween.

3. The battery module according to claim 2, wherein the hollow portion is a single hole extending across the entire space between the pressure side plate and the rear side plate.

4. The battery module according to claim 3, wherein the hollow portion is formed such that the rear surface of the pressure side plate is a convex spherical surface.

5. The battery module according to claim 2, wherein the hollow portion has radial ribs connecting the back surface of the pressure side plate and the opposing surface of the back side plate.

6. The battery module according to claim 2, wherein the hollow portion of the fixing plate is filled with an elastic material.

7. The battery module according to claim 2, wherein the fixing plate has a through-hole formed in the rear side plate that defines the hollow portion, the through-hole penetrating in the stacking direction.

8. The battery module according to claim 1, wherein the rigidity of the fixing plate is greater than the rigidity of the entire plurality of battery cells.

9. A battery pack mounted on a vehicle in a state housed in a rectangular parallelepiped housing case, comprising a battery module housed in said housing case, said battery module being a battery module according to any one of claims 1 to 8.

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