Battery module and solid-state battery module

Abstract

A battery module comprises an outer body for accommodating electrode bodies, a plurality of battery cells stacked in one direction, and a plate-shaped member disposed adjacent to at least one side of the stacking direction of the battery cells and constrained together with the battery cells, wherein the surface of the outer body on the side of the plate-shaped member comprises a constrained area in contact with the plate-shaped member and an unconstrained area not in contact with the plate-shaped member, and a reinforcing member is provided in the unconstrained area.

Description

Technology Field

[0001] The present disclosure relates to a battery module and a solid-state battery module. Background Technology

[0002] Japanese Patent Publication No. 2016-197537 discloses a battery module having a plurality of battery cells stacked in a predetermined direction. In addition, in the battery module disclosed in Japanese Patent Publication No. 2016-197537, a battery inter-cell member (plate-shaped member) is disposed between adjacent battery cells.

[0003] However, in a structure where a restraining force is applied from a plate-shaped member, such as a battery inter-cell member, to only a part of the battery cell, there is a possibility that the battery cell may expand in the unrestrained area where the plate-shaped member does not come into contact when the internal pressure of the battery cell increases. The problem to be solved

[0004] The present disclosure aims to obtain a battery module and a solid-state battery module capable of suppressing the expansion of a battery cell when internal pressure rises, while appropriately restraining the battery cell, in consideration of the above facts. means of solving the problem

[0005] A battery module of a first embodiment comprises an outer body for housing electrode bodies, a plurality of battery cells stacked in one direction, and a plate-shaped member disposed adjacent to at least one side of the stacking direction of the battery cells and constrained together with the battery cells, wherein the surface of the outer body on the side of the plate-shaped member comprises a constrained area in contact with the plate-shaped member and an unconstrained area not in contact with the plate-shaped member, and a reinforcing member is provided in the unconstrained area.

[0006] In the battery module of the first embodiment, the battery cell is provided with an outer body that accommodates an electrode body and is stacked in one direction. That is, a plurality of battery cells are provided in one direction. In addition, a plate-shaped member is disposed adjacent to the battery cell on at least one side of the stacking direction of the battery cells. Here, the plate-shaped member is constrained together with the battery cell.

[0007] In addition, the surface of the plate-shaped member side of the outer body is configured to include a constrained area in contact with the plate-shaped member and an unconstrained area not in contact with the plate-shaped member, and a reinforcing member is provided in the unconstrained area. In this way, by reinforcing the unconstrained area with the reinforcing member, the expansion of the unconstrained area can be suppressed when the internal pressure of the battery cell rises.

[0008] In the second embodiment, the battery module is configured such that, in the first embodiment, the reinforcing member comprises at least one of a convex shape portion and a concave shape portion provided in the unconstrained region of the outer body.

[0009] In the battery module of the second embodiment, the reinforcing member is configured to include at least one of a convex shape and a concave shape. By doing so, the unconstrained area can be reinforced with a simple structure.

[0010] In the battery module of the third embodiment, in the second embodiment, the reinforcing member is configured to include a concave shape portion that is recessed into the inner side of the outer body, and the concave shape portion is provided at a position that does not overlap with the electrode body when viewed in the stacking direction.

[0011] In the battery module of the third embodiment, since the reinforcing member is configured to include a concave shape portion that is recessed into the inner side of the outer body, interference between the reinforcing member and the outer part of the battery cell can be suppressed. In addition, since the concave shape portion is provided at a position that does not overlap with the electrode body when viewed in the stacking direction, the unconstrained area can be reinforced by utilizing the dead space where the electrode body is not present.

[0012] In the battery module of the fourth embodiment, in the second embodiment, the reinforcing member is configured to include a convex shape portion protruding outwardly from the outer side of the outer body, and the maximum protrusion amount of the convex shape portion is smaller than the thickness of the plate-shaped member.

[0013] In the battery module of the fourth embodiment, since the reinforcing member is configured to include a convex shape portion protruding outward from the outer surface of the outer body, interference between the reinforcing member and the internal components of the battery cell can be suppressed. Additionally, since the maximum protrusion amount of the convex shape portion is smaller than the thickness of the plate-shaped member, interference between the convex shape portion and an adjacent battery cell can be suppressed.

[0014] In the fifth embodiment, the battery module is configured such that, in the second embodiment, the outer body comprises a case body having an opening and a cover body welded to the case body to close the opening of the case body, and the convex shape portion or the concave shape portion extends in a direction intersecting the welded portion of the case body and the cover body.

[0015] In the battery module of the fifth embodiment, the convex or concave portions extend in a direction intersecting the welded portion between the case body and the cover body. By doing so, the expansion of the welded portion, which is relatively structurally weak, can be effectively suppressed.

[0016] In the battery module of the sixth embodiment, in the fifth embodiment, the protrusion amount of the convex shape portion or the concave shape portion becomes larger as it approaches the weld portion.

[0017] In the battery module of the sixth embodiment, expansion near the weld can be effectively suppressed by increasing the protrusion amount of the convex or concave portion as it approaches the weld. Additionally, interference with surrounding components can be suppressed by making the protrusion amount of the convex or concave portion relatively small at a position spaced apart from the weld.

[0018] In the battery module of the seventh embodiment, in the first embodiment, the reinforcing member is provided in the central portion of the outer body in a direction orthogonal to the stacking direction.

[0019] In the battery module of the seventh embodiment, since the central part of the outer body in the direction orthogonal to the stacking direction is most prone to expansion, the expansion of the outer body can be effectively suppressed by reinforcing this part.

[0020] In the battery module of the eighth embodiment, in the first embodiment, the unconstrained region is provided on both sides with the constrained region in between, and the reinforcing member is provided in the unconstrained region on both sides.

[0021] In the battery module of the eighth embodiment, the expansion of the unconstrained regions on both sides can be suppressed.

[0022] In the battery module of the ninth embodiment, in the eighth embodiment, the reinforcing member is provided at a position corresponding to one unconstrained area and the other unconstrained area.

[0023] In the battery module of the ninth embodiment, reinforcement can be performed without deviation between the above-mentioned unconstrained area on one side and the unconstrained area on the other side.

[0024] In the 10th embodiment of the battery module, in the 8th embodiment, the outer body is configured to include a case body having an opening and a cover body welded to the case body to close the opening of the case body, and the reinforcing member is provided more on the side of the unconstrained area closer to the cover body.

[0025] In the battery module of the 10th embodiment, by increasing the number of reinforcement parts in the unconfined area close to the cover body, the unconfined area close to the cover body, which is more vulnerable, can be effectively reinforced.

[0026] In the battery module of the eleventh embodiment, in the first embodiment, the plate-shaped member is arranged adjacent to only one side of the outer body, and the reinforcing member is provided only on the side adjacent to the plate-shaped member.

[0027] In the battery module of the 11th embodiment, by providing a reinforcing member only on the surface adjacent to the plate-shaped member in the outer body, the expansion of the surface where the reinforcing member is not provided is encouraged, and the expansion of the unconstrained area can be suppressed.

[0028] In the battery module of the 12th embodiment, in the first embodiment, the plate-shaped member is positioned so that the entire portion overlaps with the electrode body when viewed from the stacking direction.

[0029] In the battery module of the 12th embodiment, since the entire plate-shaped member receives a reaction force from the electrode body, the deformation of the outer body due to the restraining force input from the plate-shaped member can be suppressed.

[0030] In the battery module of the 13th embodiment, in the first embodiment, restraining members are provided on both sides of a stacked group in which a plurality of the battery cells are stacked, for applying a restraining force to the battery cells and the plate-shaped members, and the number of reinforcing members is greater on the side closer to the restraining members than on the side farther from the restraining members in the outer body.

[0031] In the battery module of the 13th embodiment, since the restraining force received on the side of the outer body closer to the restraining member is greater, the number of reinforcing members can be increased so that the outer body can be appropriately reinforced according to the load input to it.

[0032] A solid-state battery module of the 14th embodiment comprises an outer body for housing electrode bodies, a plurality of battery cells stacked in one direction and having a solid electrolyte as an electrolyte, and a plate-shaped member disposed adjacent to at least one side of the stacking direction of the battery cells and constrained together with the battery cells, wherein the surface of the outer body on the side of the plate-shaped member comprises a constrained region in contact with the plate-shaped member and an unconstrained region not in contact with the plate-shaped member, and a reinforcing member is provided in the unconstrained region. Effects of the invention

[0033] As described above, according to the battery module and solid-state battery module of the present disclosure, it is possible to suppress the expansion of the battery cell when the internal pressure rises while appropriately restraining the battery cell. Brief explanation of the drawing

[0034] Exemplary embodiments of the present disclosure are described in detail based on the following drawings. FIG. 1 is a front view showing the main parts of a battery module according to an embodiment. FIG. 2 is a perspective view showing the main parts of a battery module according to an embodiment. Figure 3 is an enlarged cross-sectional view showing the state cut along line 3-3 of Figure 1. Figure 4 is an enlarged cross-sectional view showing the state cut along line 4-4 of Figure 3. FIG. 5 is an enlarged cross-sectional view corresponding to FIG. 4 showing the main part of the battery cell in the first modified example. FIG. 6 is an enlarged cross-sectional view corresponding to FIG. 4 showing the main part of the battery cell in the second modified example. FIG. 7 is a perspective view corresponding to FIG. 2 showing the main part of a battery module according to a third modified example. FIG. 8 is an enlarged front view showing the main part of a battery module according to the fourth modified example. Specific details for implementing the invention

[0035] FIG. 1 is a front view showing the main parts of a battery module (10) according to an embodiment. As shown in FIG. 1, the battery module (10) is configured to include a plurality of battery cells (12) stacked along a predetermined direction and a plurality of plate-shaped members (14) interposed between adjacent battery cells (12). In addition, the battery module (10) of the present embodiment is a solid battery module having a solid electrolyte as the electrolyte.

[0036] For example, the battery module (10) of the present embodiment comprises a battery pack mounted on the bottom of a battery electric vehicle (BEV), and the battery pack comprises a plurality of battery modules (10). In addition, in addition to BEVs, it may be applied to, for example, hybrid vehicles (HEV) equipped with engines or plug-in hybrid electric vehicles (PHEV).

[0037] Additionally, in each drawing, the arrow OUT indicates the outer side in the width direction of the battery module (10), the arrow UP indicates the upward direction of the battery module (10), and the arrow FR indicates the front direction of the battery module (10). In the following description, when using the directions of front, back, left, right, up, and down, unless otherwise specified, the directions of the battery module (10) shall be indicated. However, the directions of the battery module (10) in the front, back, left, right, up, and down do not have to coincide with the directions of the vehicle in the front, back, left, right, up, and down.

[0038] In the present embodiment, as an example, the battery module (10) has seven battery cells (12) stacked in the width direction. Additionally, restraining members (16) are provided on both sides in the width direction of the stacked group in which seven battery cells (12) are stacked. A pair of restraining members (16) are each formed in the shape of a roughly rectangular plate and are formed to have a longer vertical length than the battery cells (12) and the plate-shaped member (14).

[0039] One restraining member (16) is in contact with the battery cell (12) on the side of the width direction of the battery module (10), and the other restraining member (16) is in contact with the battery cell (12) on the other side of the width direction of the battery module (10). Because of this, among the battery cells (12) constituting the battery module (10), the battery cells (12) located at both ends in the width direction have plate-shaped members (14) arranged only on one side, and the remaining battery cells (12) have plate-shaped members (14) arranged on both sides in the width direction. Because of this, the structure is such that six plate-shaped members (14) are arranged between seven battery cells (12).

[0040] A rod (18) is passed through the upper and lower portions of each pair of restraining members (16). The rod (18) is a rod-shaped member extending in the width direction, and two are provided spaced apart in the front-rear direction. Because of this, the structure is such that the rod (18) is passed through the four corner portions of the restraining member (16), which is approximately rectangular plate-shaped.

[0041] Screw grooves not shown are formed at both ends of the rod (18), and a nut (20) is screwed in from the outer side in the width direction of the restraining member (16). Then, by tightening the nut (20), the gap between the pair of restraining members (16) is narrowed, and a restraining force is applied to the battery cell (12) and the plate-shaped member (14). Additionally, any other structure capable of applying a restraining force to the battery cell (12) and the plate-shaped member (14) may be adopted. For example, one restraining member (16) and the rod (18) may be firmly connected, and only the other restraining member (16) may be configured to be slidable.

[0042] FIG. 2 is a perspective view showing the main part of a battery module (10) according to an embodiment. As shown in FIG. 2, the battery cell (12) constituting the battery module (10) is formed in a roughly rectangular shape having a short side and a long side when viewed in the stacking direction. In this embodiment, as an example, since the vertical direction is the long side side, the battery cell (12) is formed in a roughly rectangular shape that is vertically long when viewed in the stacking direction.

[0043] Additionally, the battery cell (12) is provided with an outer body (22) that is approximately box-shaped, and two external terminals (24) are provided at the upper portion of the outer body (22). The external terminals (24) are electrically connected to an electrode body (30) (see FIG. 3) housed inside the outer body (22). The outer body (22) is formed from a thin-walled metal substrate. As the metal substrate, a metal substrate including aluminum, a metal substrate including stainless steel, etc., which are conventionally known, may be used. The thickness of the metal substrate is preferably 1 mm or less, more preferably 0.2 mm to 0.5 mm, and even more preferably 0.3 mm to 0.5 mm.

[0044] In addition, in this embodiment, as an example, a structure in which two external terminals (24) are provided on one end of the battery cell (12) is described, but it is not limited thereto. For example, a structure in which external terminals are provided on one end and the other end of the battery cell (12) may be adopted. In addition, a structure in which external terminals are provided on the long side of the outer body (22) may be adopted.

[0045] The plate-shaped member (14) is formed in a roughly rectangular shape having a short side and a long side when viewed in the stacking direction, and in this embodiment, as an example, is formed of an insulating material. For example, the plate-shaped member (14) is composed of a silica aerogel with a thermal conductivity of 0.03 W / (m·K) or less and made of silica as the main material. In addition, from the perspective of thermal insulation performance, a silica aerogel composed of a silicon dioxide framework and 90% to 98% air is preferred, and it is more preferable that it be a material with excellent flame retardancy. The plate-shaped member (14) is not limited to this and may be an elastic body, and for example, may be a resin.

[0046] Here, the plate-shaped member (14) is positioned adjacent to at least one side of the stacking direction of the battery cell (12) and is constrained together with the battery cell (12). Additionally, the plate-shaped member (14) is interposed between the battery cells (12). Furthermore, the plate-shaped member (14) has a shape smaller than the outer body (22) of the battery cell (12), and when viewed in the stacking direction, the entire plate-shaped member (14) overlaps with the battery cell (12). Additionally, the long side of the plate-shaped member (14) is positioned parallel to the long side of the outer body (22) of the battery cell (12), and the short side of the plate-shaped member (14) is positioned parallel to the short side of the outer body (22) of the battery cell (12).

[0047] The surface of the outer body (22) on the side of the plate-shaped member (14) is configured to include a constrained area AR1 that contacts the plate-shaped member (14) and an unconstrained area AR2 that does not contact the plate-shaped member (14). In the constrained area AR1, a constraining force is applied from the plate-shaped member (14) to the outer body (22) in a stacking direction.

[0048] The unconstrained area AR2 refers to an area that is not in contact with the plate-shaped member (14) on the surface facing the plate-shaped member (14) in the outer body (22), and in this embodiment, as an example, the area of ​​the constrained area AR1 is set to be at least 6 times the area of ​​the unconstrained area AR2.

[0049] In addition, in this embodiment, as an example, the length along the short side in the restraint area AR1 is set to be 95% or more of the length along the short side of the outer body (22). Accordingly, the length of the outer body (22) protruding in the front-rear direction relative to the plate-shaped member (14) is 5% or less of the front-rear direction length of the outer body (22).

[0050] In addition, in this embodiment, the plate-shaped member (14) is formed as an insulating material, but it is not limited to this. For example, a member with a thermal conductivity greater than 0.03 W / (m·K) may be used. In this case as well, by interposing the plate-shaped member between the battery cells (12), it is possible to effectively suppress the expansion of the battery cells (12) by preventing gas from being generated inside the battery cells (12).

[0051] Here, in the unconstrained region AR2 of the outer body, a convex shape portion (22A) serving as a reinforcing part is provided. Multiple convex shape portions (22A) are provided in the unconstrained region AR2, and each protrudes outward from the outer side of the outer body (22).

[0052] In the present embodiment, as an example, the unconstrained region AR2 is provided on both the upper and lower sides with the constrained region AR1 in between, and each unconstrained region AR2 has three convex shaped portions (22A). Additionally, each convex shaped portion (22A) extends in the vertical direction and is formed at approximately equal intervals along the front-rear direction.

[0053] Among the three convex-shaped portions (22A), the central convex-shaped portion (22A) is located in the central part of the front-rear direction (a direction perpendicular to the stacking direction) of the outer body (22). That is, it is located in the middle of the two external terminals (24). In addition, the three upper convex-shaped portions (22A) and the three lower convex-shaped portions (22A) are provided at corresponding positions. Because of this, the lower convex-shaped portion (22A) is located on the extension line of the extension direction of the upper convex-shaped portion (22A).

[0054] FIG. 3 is an enlarged cross-sectional view showing the state cut along line 3-3 of FIG. 1. As shown in FIG. 3, the outer body (22) is configured to include a case body (26) having an opening and a cover body (28) that closes the opening of the case body (26). As an example, the case body (26) of the present embodiment is formed in the shape of a rectangular tube with a bottom and has an open top.

[0055] The cover body (28) is formed to be thicker than the case body (26). In other words, the case body (26) is formed to be thinner than the cover body (28). Additionally, the cover body (28) is joined to the case body (26) by welding, and a welded portion (40) is provided at the boundary between the case body (26) and the cover body (28). Additionally, two external terminals (24) are inserted through the cover body (28).

[0056] An electrode body (30) is housed inside the case body (26) constituting the battery cell (12). The electrode body (30) is formed by stacking a positive electrode current collector, a positive electrode active material, a solid electrolyte, a negative electrode active material, and a negative electrode current collector. In addition, in this embodiment, a stacked electrode body (30) is used, but a wound electrode body may be used instead of a stacked electrode body.

[0057] The positive electrode current collector and the negative electrode current collector are formed by metal foil, and examples of metal foil include aluminum foil, copper foil, nickel foil, titanium foil, stainless steel foil, etc. Additionally, a coating layer may be formed on the surface of the current collector, and the coating layer may be formed by known methods such as plating or spray coating. Furthermore, aluminum foil is preferred for the positive electrode current collector, and copper foil is preferred for the negative electrode current collector.

[0058] As for the positive electrode active material, it is not particularly limited, and conventionally known materials can be appropriately used. For example, as positive electrode active materials, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li(NiCoMn)O2, Li(NiCoAl)O2, and LiFePO4 can be used. In addition, the positive electrode active material particles may be Hi-Nickel (a positive electrode active material with a high proportion of Ni), Li-Ni-Co-Mn-based composite oxides, or ternary positive electrode active materials.

[0059] As a negative electrode active material, for example, natural graphite, artificial graphite, hard carbon (non-graphitizable carbon) or soft carbon (digraphitizable carbon), Si, SiOx(0 <x<2), Si기 합금, Sn, SnOx (0<x<2), Li, Li기 합금 및 Li4Ti5O 12 At least one type selected from the group consisting of can be cited. Examples of artificial graphite include highly oriented graphite, mesocarbon micro beads, etc. As for the negative electrode active material, artificial graphite is preferred.

[0060] Furthermore, the solid electrolyte is not particularly limited, and conventionally known materials may be appropriately used; examples include sulfide-based solid electrolytes, oxide-based solid electrolytes, and polymer-based solid electrolytes. When a sulfide-based solid electrolyte is used as the solid electrolyte, gas is likely to be generated as the sulfide-based solid electrolyte reacts with water. Additionally, a liquid electrolyte may be used instead of a solid electrolyte. As for the electrolyte, a solid electrolyte is preferred in which the binding force is set higher compared to a liquid electrolyte.

[0061] At the upper part of the electrode body (30), a positive electrode current collection tab (32) and a negative electrode current collection tab (34) are provided. The positive electrode current collection member constituting the electrode body (30) is connected to the positive electrode current collection tab (32) in a bundled state. The positive electrode current collection tab (32) is connected to a positive electrode current collection terminal (36) provided on the lower surface of the cover body (28). That is, the positive electrode current collection tab (32) connects the electrode body (30) and the positive electrode current collection terminal (36).

[0062] The negative electrode current collector constituting the electrode body (30) is connected to the negative electrode current collector in a bundled state. The negative electrode current collector (34) is connected to the negative electrode current collector terminal (38) provided on the lower surface of the cover body (28). That is, the negative electrode current collector (34) connects the electrode body (30) and the negative electrode current collector terminal (38).

[0063] One external terminal (24) is connected to the positive current collector terminal (36), and the other external terminal (24) is connected to the negative current collector terminal (38).

[0064] FIG. 4 is an enlarged cross-sectional view showing the state cut along line 4-4 of FIG. 3. As shown in FIG. 4, the positive electrode current collection tab (32) is configured to include an electrode body side connection part (32A) connected to the electrode body (30), a terminal side connection part (32B) connected to the positive electrode current collection terminal (36), and a curved part (32C) connecting the electrode body side connection part (32A) and the terminal side connection part (32B).

[0065] The curved portion (32C) is curved to bulge out toward one side of the width direction when viewed from the front-rear direction, which is orthogonal to the width direction, which is the stacking direction. Because of this, the internal space of the upper part of the battery cell (12) has the curved portion (32C) positioned toward one side of the width direction, and the other side of the width direction is a relatively wide space.

[0066] Additionally, the electrode body (30) housed in the case body (26) extends upward above the plate-shaped member (14). Also, although not shown, the electrode body (30) extends downward below the plate-shaped member (14). Because of this, the plate-shaped member (14) is positioned so that its entire surface overlaps with the electrode body (30) when viewed from the stacking direction.

[0067] The convex shape portion (22A) serving as a reinforcing part is formed by press-forming a part of the case body (26), and the maximum protrusion amount of the convex shape portion (22A) is smaller than the thickness of the plate-shaped member (14). More specifically, the maximum protrusion amount of the convex shape portion (22A) is smaller than half the thickness of the plate-shaped member (14). Because of this, it is configured so as not to interfere with the convex shape portion (22A) provided in the adjacent battery cell (12). The maximum protrusion amount is the protrusion amount at the position where the protrusion amount (height) from the surface forming the unconstrained region AR2 among the convex shape portions (22A) becomes maximum.

[0068] Additionally, while the welded portion (40) of the case body (26) and the cover body (28) extends in the front-rear and width directions, the convex portion (22A) extends in the vertical direction intersecting the welded portion (40). In this embodiment, as an example, the convex portion (22A) extends in a direction approximately orthogonal to the welded portion (40).

[0069] (action)

[0070] Next, the operation of the battery module (10) according to the present embodiment is explained.

[0071] In the battery module (10) according to the present embodiment, as shown in FIG. 1, a plurality of battery cells (12) are stacked in one direction, and a plate-shaped member (14) is disposed adjacent to the battery cells (12) on at least one side of the stacking direction of the battery cells (12). The plate-shaped member (14) is constrained together with the battery cells (12). In addition, as shown in FIG. 2 to FIG. 4, the battery cells (12) are provided with an outer body (22) that accommodates an electrode body (30), and the surface of the outer body (22) on the side of the plate-shaped member (14) is configured to include a constrained area AR1 that contacts the plate-shaped member (14) and an unconstrained area AR2 that does not contact the plate-shaped member (14).

[0072] Here, as shown in FIG. 4, a convex shape (22A) as a reinforcing part is provided in the unconstrained region AR2. In this way, by reinforcing the unconstrained region AR2 with the convex shape (22A), the expansion of the unconstrained region AR2 can be suppressed when the internal pressure of the battery cell (12) rises.

[0073] Specifically, when the internal pressure of the battery cell (12) rises due to a difference in elevation or gas generation inside, the outer body (22) attempts to expand, but the battery cell (12) cannot expand because the constrained region AR1 is constrained by the plate-shaped member (14). Because of this, the outer body (22) attempts to expand outward in the unconstrained region AR2. Even in this state, the unconstrained region AR2 is reinforced by the convex shape part (22A), so the outer body (22) can be prevented from expanding significantly.

[0074] In particular, in this embodiment, since the reinforcement part is formed by a plurality of convex shape parts (22A), the unconstrained area can be reinforced with a simple structure. In addition, since the convex shape parts (22A) protrude to the outside of the outer body (22), interference between the convex shape parts (22A) and the internal parts of the battery cell (12) can be suppressed.

[0075] In addition, since the protrusion amount of the convex shape portion (22A) is smaller than the thickness of the plate shape member (14), interference between the convex shape portion (22A) and the adjacent battery cell (12) can be suppressed.

[0076] In addition, in this embodiment, since the convex shape portion (22A) extends in a direction intersecting the weld (40) of the case body (26) and the cover body (28), it is possible to effectively suppress the expansion of the weld (40), which is relatively structurally weak. Specifically, if the case body (26) expands outward, there is a possibility that the load will be concentrated on the end weld (40) of the case body (26). Conversely, as in this embodiment, by extending the convex shape portion (22A) in a direction intersecting the weld (40), the expansion that concentrates the load on the weld (40) can be suppressed, thereby maintaining a good bonding state between the case body (26) and the cover body (28).

[0077] In addition, in this embodiment, as shown in FIG. 2, a convex shape portion (22A) is provided in the central portion of the front-rear direction, which is orthogonal to the vertical direction of the stacking direction of the outer body (22), thereby reinforcing the part most prone to expansion and effectively suppressing the expansion of the outer body (22).

[0078] In addition, as in the present embodiment, unconstrained regions AR2 are provided on both sides with a constrained region AR1 in between, and by providing convex shaped portions (22A) on the unconstrained regions AR2 on both sides, the expansion of the unconstrained regions AR2 on both sides can be suppressed.

[0079] In addition, in this embodiment, by providing a convex shape portion (22A) at a position corresponding to one unconstrained area AR2 and the other unconstrained area AR2, reinforcement can be achieved without deviation.

[0080] In addition, in this embodiment, since the entire plate-shaped member (14) is positioned to overlap with the electrode body (30), the entire plate-shaped member (14) receives a reaction force from the electrode body (30). Because of this, the deformation of the outer body (22) due to the restraining force input from the plate-shaped member (14) can be suppressed.

[0081] In addition, the structure is not limited to the present embodiment, and the structure described in the first variant shown in FIG. 5 to the fourth variant shown in FIG. 8 may be adopted.

[0082] (1st variation)

[0083] FIG. 5 is an enlarged cross-sectional view corresponding to FIG. 4, showing the main part of the battery cell in the first modified example. As shown in FIG. 5, in this modified example, the shape of the convex part (22A) is different.

[0084] Specifically, the outer body (52) constituting the battery module (50) according to the present modification is configured to include a case body (54) having an opening and a cover body (28) that closes the opening of the case body (54). As an example, the case body (54) is formed in the shape of a rectangular tube with a bottom and has an open top.

[0085] The cover body (28) is joined to the case body (54) by welding, and a weld (40) is provided at the boundary between the case body (54) and the cover body (28). Additionally, two external terminals (24) are inserted through the cover body (28).

[0086] The case body (54) is provided with a convex shape portion (52A) as a reinforcing part. The convex shape portion (52A) is formed by press-forming a part of the case body (54), and the maximum protrusion amount of the convex shape portion (52A) is smaller than the thickness of the plate-shaped member (14).

[0087] In addition, the convex shape portion (22A) of the present variation protrudes outward from the unconstrained area AR2 of the outer body (22), and the convex shape portion (52A) formed on one side in the width direction of the case body (54) and the convex shape portion (52A) formed on the other side in the width direction have approximately the same shape.

[0088] Here, in this modified example, the convex shape portion (52A) has a larger protrusion amount as it approaches the weld portion (40). Specifically, the convex shape portion (52A) has a different protrusion amount in the vertical direction and is formed in a roughly tapered shape so that the protrusion amount increases as it moves from the bottom to the top.

[0089] Additionally, since the welded portion (40) of the case body (54) and the cover body (28) is located at the upper part of the case body (26), the protruding amount of the convex shape portion (52A) becomes larger as it approaches the welded portion (40).

[0090] As in the present modified example, as the amount of protrusion of the convex shape portion (52A) increases as it approaches the weld portion (40), expansion near the weld portion (40) can be effectively suppressed. In addition, at a position spaced apart from the weld portion (40), interference with surrounding parts can be suppressed by making the amount of protrusion of the convex shape portion (52A) relatively small.

[0091] (2nd variation)

[0092] FIG. 6 is an enlarged cross-sectional view corresponding to FIG. 4, showing the main part of the battery cell in the second modified example. As shown in FIG. 6, in the present modified example, a concave shape is formed instead of a convex shape.

[0093] Specifically, the outer body (62) of the battery cell constituting the battery module (60) according to the present modification is configured to include a case body (64) having an opening and a cover body (28) that closes the opening of the case body (64). As an example, the case body (64) is formed in the shape of a rectangular tube with a bottom and has an open top.

[0094] The cover body (28) is joined to the case body (64) by welding, and a weld (40) is provided at the boundary between the case body (64) and the cover body (28). Additionally, two external terminals (24) are inserted through the cover body (28).

[0095] The case body (64) is provided with a concave shape portion (62A) as a reinforcing part. The concave shape portion (62A) is formed by press-forming a part of the case body (64), and the maximum protrusion amount in the width direction of the concave shape portion (62A) is smaller than the thickness of the plate-shaped member (14).

[0096] Additionally, the concave shape portion (62A) is shaped to be concavely inwardly into the case body (64) constituting the outer body (62), and the concave shape portion (62A) is provided at a position that does not overlap with the electrode body (30) when viewed from the stacking direction.

[0097] In this modified example, since the concave shape portion (62A) is concavely recessed into the inner side of the outer body (62), interference between the concave shape portion (62A) and the outer part of the battery cell (12) can be suppressed. Additionally, since the concave shape portion (62A) is provided at a position that does not overlap with the electrode body (30) when viewed from the stacking direction, the unconstrained region AR2 can be reinforced by utilizing the dead space where the electrode body (30) is not present.

[0098] In addition, the shape or number of the concave shape portions (62A) are not specifically limited. For example, three concave shape portions (62A) of each unconstrained area AR2 may be provided, as in the embodiment.

[0099] (Third Variation Example)

[0100] FIG. 7 is a perspective view corresponding to FIG. 2 showing the main part of a battery module (70) according to a third modified example. As shown in FIG. 7, in the battery module (70) of the present modified example, the number of convex shaped parts (22A) as reinforcing parts provided in the battery cell (12) is different.

[0101] Specifically, five convex shaped portions (22A) are provided in the unconstrained area AR2 on the side close to the external terminal (24) (cover body). Meanwhile, three convex shaped portions (22A) are provided in the unconstrained area AR2 on the side far from the external terminal, just as in the embodiment.

[0102] As in this modified example, by increasing the number of convex shape portions (22A) of the unconstrained region AR2 near the cover body, the unconstrained region AR2 near the cover body, which is more vulnerable, can be effectively reinforced.

[0103] In addition, in this modified example, the same number of convex shaped portions (22A) are provided for the unconstrained area AR2 on the opposite side of the case body (26), but this is not limited thereto. For example, different numbers of convex shaped portions (22A) may be provided on one side and the other side, and five convex shaped portions (22A) may be provided on one side in the width direction and three convex shaped portions (22A) may be provided on the other side in the width direction.

[0104] (Fourth variant)

[0105] FIG. 8 is an enlarged front view showing the main part of a battery module according to the fourth modified example. As shown in FIG. 8, in the battery module (80) of the present modified example, the number of convex shaped parts (22A) is different for each battery cell (12).

[0106] Specifically, the battery cell (12) adjacent to the restraining member (16) has a plate-shaped member (14) disposed on only one side. Additionally, since the entire surface of the other side of the battery cell (12) is in contact with the restraining member (16), the battery cell (12) adjacent to the restraining member (16) has a convex-shaped portion (22A) provided on only one side of the outer body (22).

[0107] Here, in the battery cell (12), the surface in contact with the restraining member (16) has a restraining force applied to the entire surface by the restraining member (16), so the surface on the restraining member (16) side does not expand even when the internal pressure of the battery cell (12) increases.

[0108] Meanwhile, on the other side of the outer body (22) of the battery cell (12), a convex shape portion (22A) is provided, and expansion is suppressed by being reinforced by the convex shape portion (22A).

[0109] Additionally, the battery cell (12) not adjacent to the restraining member (16) has convex shaped portions (22A) provided on both sides of the surface on one side and the surface on the other side in the width direction of the outer body (22). Here, although not illustrated, the number of convex shaped portions (22A) is greater on the side closer to the restraining member (16) than on the side farther from the restraining member (16). Specifically, among the two battery cells (12) shown in FIG. 8, in the battery cell (12) not adjacent to the restraining member (16), five convex shaped portions (22A) are provided in the front-rear direction on the side of the outer body (22) close to the restraining member (16). Additionally, three convex shaped portions (22A) are provided in the front-rear direction on the side of the outer body (22) farther from the restraining member (16).

[0110] In addition, in this modified example, as shown in FIG. 1, seven battery cells (12) are arranged in the width direction. Because of this, in the battery cell (12) located in the center of the width direction, three convex shapes (22A) are provided on each side of the outer body (22), and in the other battery cell (12), five convex shapes (22A) are provided on the side close to the restraining member (16).

[0111] In this modified example, by providing a convex shape portion (22A) only on the surface adjacent to the plate-shaped member (14) in the outer body (22), it is not necessary to provide an unnecessary convex shape portion (22A). Additionally, since the restraining force received on the side of the outer body (22) closer to the restraining member (16) increases, the number of convex shape portions (22A) is increased so that the outer body (22) can be reinforced appropriately according to the load input to it. That is, the outer body (22) can be reinforced to the same degree against external force on the side closer to the restraining member (16) and the side farther away.

[0112] Although the battery module according to the above embodiments and variations has been described, it is not limited thereto, and it is understood that it can be implemented in various forms within the scope of not departing from the gist of the present disclosure. For example, in the above embodiment, as shown in FIG. 2, the plate-shaped member (14) is formed in a roughly rectangular plate shape, but it is not limited thereto and may be in other shapes.

[0113] In addition, in the above embodiment, the entire plate-shaped member (14) is arranged to overlap with the battery cell (12) when viewed in the stacking direction, but this is not limited thereto. For example, a part of the plate-shaped member (14) may be arranged in a position that does not overlap with the battery cell (12) when viewed in the stacking direction. Specifically, the upper end of the plate-shaped member (14) may be arranged to be positioned above the upper end of the battery cell (12).

[0114] In addition, the plate-shaped member (14) may be divided into multiple parts, and may have holes or concave parts formed on its surface.

[0115] In addition, in the above embodiment, the reinforcing member is formed by at least one of the convex shape portion and the concave shape portion, but it is not limited thereto and the reinforcing member may be formed with other structures. For example, a thick portion with a thickness greater than that of the constrained area may be formed in an unconstrained area that does not come into contact with the plate-shaped member of the exterior body, and this thick portion may be used as the reinforcing member.

[0116] In addition, in the above embodiment, the convex and concave portions are structured to extend in the vertical direction of the battery cell, but are not limited thereto. For example, the convex and concave portions may be extended in the front-rear direction of the battery cell. Furthermore, the convex and concave portions may be formed in a roughly cross shape, a roughly elliptical shape, etc.

[0117] In addition, in the above embodiment, the protrusion amount of the convex shape portion is less than or equal to half the thickness of the plate-shaped member, but this is not limited thereto. For example, even if the protrusion amount of the convex shape portion is formed to be more than half the thickness of the plate-shaped member, if the convex shape portion is formed at a different location on an adjacent battery cell, the convex shape portions do not need to interfere with each other. In addition, even if a convex shape portion is provided on one side of an adjacent battery cell and a concave shape portion is provided on the other side, there is no need for interference.

[0118] Regarding the above embodiment, the following supplementary information is disclosed.

[0119] (Appendix 1)

[0120] A plurality of battery cells stacked in one direction, having an outer body that accommodates electrode bodies, and

[0121] A plate-shaped member disposed adjacent to at least one side of the stacking direction of the battery cell and constrained together with the battery cell

[0122] Have,

[0123] The surface of the plate-shaped member side of the above-mentioned exterior body is configured to include a constrained area in contact with the plate-shaped member and an unconstrained area that does not contact the plate-shaped member.

[0124] A battery module having a reinforcing member provided in the above-mentioned unconstrained area.

[0125] (Appendix 2)

[0126] The battery module described in Appendix 1, wherein the reinforcing member comprises at least one of a convex shape portion and a concave shape portion provided in the unconstrained region of the outer body.

[0127] (Appendix 3)

[0128] The above reinforcing member is configured to include a concave shape portion that is recessed into the inner side of the exterior body, and

[0129] The battery module described in Appendix 2, wherein the above-mentioned concave shape portion is provided at a position that does not overlap with the electrode body when viewed from the stacking direction.

[0130] (Appendix 4)

[0131] The above reinforcing member is configured to include a convex shape portion protruding outward from the exterior body, and

[0132] A battery module described in Appendix 2, wherein the maximum protrusion amount of the above convex shape portion is smaller than the thickness of the above plate shape member.

[0133] (Appendix 5)

[0134] The above-mentioned exterior body is composed of a case body having an opening and a cover body welded to the case to close the opening of the case.

[0135] A battery module described in any one of Appendix 2 to Appendix 4, wherein the convex shape portion or the concave shape portion extends in a direction intersecting the welded portion of the case body and the cover body.

[0136] (Appendix 6)

[0137] A battery module described in Appendix 5, wherein the convex shape portion or the concave shape portion has a protrusion amount that increases as it approaches the weld portion.

[0138] (Appendix 7)

[0139] The above reinforcing member is a battery module described in any one of Appendix 1 to Appendix 6, which is provided in a central portion of the outer body in a direction orthogonal to the stacking direction.

[0140] (Appendix 8)

[0141] The above-mentioned unconstrained regions are provided on both sides with the above-mentioned constrained regions in between, and

[0142] The above reinforcing member is a battery module described in any one of Appendix 1 to Appendix 7, provided in the above-mentioned unconstrained regions on both sides.

[0143] (Appendix 9)

[0144] The above reinforcing member is a battery module described in Appendix 8, which is provided at a position corresponding to one unconstrained area and the other unconstrained area.

[0145] (Appendix 10)

[0146] The above-mentioned exterior body is composed of a case body having an opening and a cover body welded to the case to close the opening of the case.

[0147] The above reinforcing member is a battery module described in Appendix 8, wherein the unconstrained area near the above cover body is provided in large portions.

[0148] (Appendix 11)

[0149] The above plate-shaped member is arranged adjacent to only one surface of the above exterior body, and

[0150] The above reinforcing member is provided only on the surface adjacent to the plate-shaped member, and is a battery module described in any one of Appendix 1 to Appendix 10.

[0151] (Appendix 12)

[0152] The above plate-shaped member is a battery module described in any one of Appendix 1 to Appendix 11, wherein the entire plate-shaped member is positioned to overlap with the electrode body when viewed in the stacking direction.

[0153] (Appendix 13)

[0154] On both sides of a stacked group in which a plurality of the above-mentioned battery cells are stacked, restraining members are provided to apply a restraining force to the battery cells and the plate-shaped member.

[0155] A battery module described in any one of Appendix 1 to Appendix 12, wherein the side closer to the restraining member in the above-mentioned exterior body has a greater number of reinforcing members than the side farther from the restraining member.

Claims

Claim 1 A battery module comprising an outer body for accommodating electrode bodies, a plurality of battery cells stacked in one direction, and a plate-shaped member disposed adjacent to at least one side of the stacking direction of the battery cells and constrained together with the battery cells, wherein the surface of the outer body on the side of the plate-shaped member comprises a constrained area in contact with the plate-shaped member and an unconstrained area not in contact with the plate-shaped member, and wherein a reinforcing member is provided in the unconstrained area. Claim 2 A battery module according to claim 1, wherein the reinforcing member comprises at least one of a convex shape portion and a concave shape portion provided in the unconstrained region of the outer body. Claim 3 In paragraph 2, the reinforcing member is configured to include a concave shape portion that is recessed into the inner side of the outer body, and the concave shape portion is provided at a position that does not overlap with the electrode body when viewed from the stacking direction, a battery module. Claim 4 In paragraph 2, the reinforcing member is configured to include a convex shape portion protruding outward from the outer side of the outer body, and the maximum protrusion amount of the convex shape portion is smaller than the thickness of the plate-shaped member, in a battery module. Claim 5 In paragraph 2, the battery module comprises an outer body having an opening and a cover body welded to the case body to close the opening of the case body, wherein the convex shape portion or the concave shape portion extends in a direction intersecting the welded portion of the case body and the cover body. Claim 6 In claim 5, the battery module wherein the convex shape portion or the concave shape portion has a protrusion amount that increases as it approaches the weld portion. Claim 7 In claim 1, the reinforcing member is provided in the central portion of the outer body in a direction orthogonal to the stacking direction. Claim 8 A battery module according to claim 1, wherein the unconstrained area is provided on both sides with the constrained area in between, and the reinforcing member is provided in the unconstrained area on both sides. Claim 9 In claim 8, the above-mentioned reinforcing member is provided at a position corresponding to one of the above-mentioned unconstrained regions and the other of the above-mentioned unconstrained region, in a battery module. Claim 10 In claim 8, the above-mentioned outer body comprises a case body having an opening and a cover body welded to the case body to close the opening of the case body, and the above-mentioned reinforcing member is provided with a larger portion of the unconstrained area closer to the cover body, in a battery module. Claim 11 A battery module according to claim 1, wherein the plate-shaped member is disposed adjacent to only one surface of the outer body, and the reinforcing member is provided only on the surface adjacent to the plate-shaped member. Claim 12 A battery module according to claim 1, wherein the plate-shaped member is positioned such that its entire portion overlaps with the electrode body when viewed in the stacking direction. Claim 13 A battery module according to claim 1, wherein on both sides of a stacked group in which a plurality of the battery cells are stacked, restraining members are provided to provide restraining force to the battery cells and the plate-shaped members, and the number of reinforcing members is greater on the side closer to the restraining members than on the side farther from the restraining members in the outer body. Claim 14 A solid battery module comprising: an outer body for accommodating electrode bodies; a plurality of battery cells stacked in one direction and having a solid electrolyte as an electrolyte; a plate-shaped member disposed adjacent to at least one side of the stacking direction of the battery cells and constrained together with the battery cells; wherein the surface of the outer body on the side of the plate-shaped member comprises a constrained region in contact with the plate-shaped member and an unconstrained region not in contact with the plate-shaped member, and a reinforcing member provided in the unconstrained region.

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