JP7178266B2 - BATTERY MODULE AND END PLATE MANUFACTURING METHOD - Google Patents

Description

The present invention relates to a battery module in which a plurality of battery cells are stacked, and a method of manufacturing end plates that sandwich the plurality of battery cells.

Hybrid cars and electric cars are equipped with a battery module in which a plurality of battery cells such as lithium-ion secondary batteries are stacked. In general, battery cells expand due to charging and discharging. Therefore, in a battery module, a plurality of battery cells are generally sandwiched between end plates, and a binding member such as a bind bar is used to fasten the end plates together to provide a restraining force. , a plurality of battery cells are sandwiched between end plates to suppress expansion of the battery cells.

Every time the battery cell is repeatedly charged and discharged, repeated stress is applied to the end plates, which easily causes plastic deformation and fatigue fracture. Therefore, the end plate needs to have a high rigidity that does not cause plastic deformation or fatigue failure even if stress is applied repeatedly. Conventionally, a technique has been proposed to increase the rigidity of the end plate itself by arranging a metal plate on the outside of the resin end plate and further by arranging a resin cover plate on the outside of the metal plate ( For example, see Patent Document 1).

JP 2014-203747 A

In recent years, as the weight of vehicles has been reduced, there has been an increasing demand for higher capacity, smaller size, and lighter weight battery modules mounted on vehicles. As the capacity of the battery module increases, the reaction force applied to the fastening member when the battery cells expand increases, so end plates are required to have greater strength and rigidity.

Generally, in order to increase the strength and rigidity of the end plate, it is necessary to increase the thickness or use a material with higher strength. As a result, the end plate has a problem of increased volume and weight.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a battery module having end plates that are strong, rigid, and lightweight, and a method for manufacturing the end plates.

(1) In the battery module according to the present invention, end plates (for example, end plates 4, 4A to 4I, which will be described later) are provided at both ends in the stacking direction of a plurality of stacked battery cells (for example, battery cells 2, which will be described later). A battery module (for example, a battery module 1 to be described later) in which the battery cells are arranged respectively and the entire battery cells are sandwiched between the end plates. , first metal plate layer 41 to be described later)/resin plate layer (for example, resin plate layer 42 to be described later)/second metal plate layer (for example, second metal plate layer 43 to be described later). Alternatively, it has a four-layer structure in which a first metal plate layer/resin plate layer/second metal plate layer/carbon fiber reinforced plastic plate layer (for example, a CFRP plate layer 45 described later) is laminated in this order, and the first The metal plate layer, the resin plate layer, and the second metal plate layer are formed by the molten resin forming the resin plate layer being in close contact with the first metal plate layer and the second metal plate layer and hardened. The resin plate layer has a thickness larger than that of each of the first metal plate layer and the second metal plate layer.

According to (1), the strength and rigidity of the end plate can be ensured by the first metal plate layer and the second metal plate layer. In order to ensure the necessary strength and rigidity, the end plate does not increase the thickness of the metal plate layer, but rather increases the thickness of the resin plate layer, which has a relatively low density. can be made large and can be made lightweight. As a result, a battery module having end plates that are lightweight while having high strength and rigidity can be configured.

(2) In the battery module described in (1), the surfaces of the first metal plate layer and the second metal plate layer in contact with the resin plate layer and the carbon fiber reinforced plastic plate layer are roughened or metallized. It is preferable that a metal-resin bonding film treatment for chemically bonding the metal and the resin is applied.

Due to (2), sliding between layers of the end plate can be suppressed, and the strength and rigidity of the end plate can be further increased.

(3) In the battery module described in (1) or (2), the resin plate layer may have a plurality of lightening portions (for example, lightening portions 422 and 423 described later).

(3) makes it possible to construct a battery module having a lightweight end plate.

(4) In the battery module described in (3), the lightening portion may extend in the height direction of the resin plate layer and may be arranged in parallel with the width direction of the resin plate layer.

(4) makes it possible to construct a battery module having lightweight end plates without greatly reducing rigidity.

(5) In the battery module described in (3), the lightening portion may extend in the width direction of the resin plate layer and may be arranged in parallel with the height direction of the resin plate layer.

(5) makes it possible to configure a battery module having a lightweight end plate without greatly reducing rigidity.

(6) In the battery module according to (4) or (5), the surface of the resin plate layer in contact with the second metal plate layer has a gap between the first metal plate layer and the second metal plate layer. It is convexly curved so as to be greatest at the central portion in the width direction, and the depth of the lightening portion from the first metal plate layer toward the second metal plate layer is equal to the width of the resin plate layer. The lightening portion arranged in the central portion may be deeper than the lightening portion arranged at both ends in the direction.

According to (6), the rigidity corresponding to the distribution of the bending moment acting on the end plate is adjusted, and deflection can be suppressed compared to the case where the end plate is formed in a flat plate shape.

(7) In the battery module described in (3), the lightening portion may have a honeycomb shape.

(7) makes it possible to increase the rigidity of the resin plate layer while reducing the weight of the end plate.

(8) In the battery module according to (1) or (2), at least one of the first metal plate layer and the second metal plate layer has, at least one end in the height direction, It is preferable to have a first bent portion (for example, an upper bent portion 432 and a lower bent portion 433 to be described later) bent toward the second metal plate layer or the first metal plate layer.

Due to (8), the geometrical moment of inertia of the end plate increases, and the rigidity in the width direction of the end plate can be further improved.

(9) In the battery module described in (8), the distal end portions of the first bent portions (for example, distal end portions 432a and 433a, which will be described later) are located inside the second metal plate layer or the first metal plate layer. It is preferably in contact with a side surface (for example, an inner side surface 43a or 41a, which will be described later).

With (9), the effect of suppressing deformation in the width direction of the end plate when bending stress acts on the end plate in the width direction can be further enhanced.

(10) The battery module according to any one of (1) to (7) has a fastening member (for example, a fastening member 5 described later) that fastens the end plates together, and the fastening member is the end plate. It is preferably fixed to the surface of the second metal plate layer or the carbon fiber reinforced plastic plate layer arranged on the outermost surface of the.

According to (10), since the fastening member is fixed to the surface of the metal plate layer instead of the resin plate layer, the stress applied to the resin plate layer at the fixed portion of the fastening member is relaxed, thereby preventing the end plate from being crushed by compression. be able to.

(11) In the battery module according to (10), the second metal plate layer or the carbon fiber reinforced plastic plate layer to which the fastening member is fixed constitutes a layer with the highest rigidity in the end plate. is preferred.

Due to (11), in the end plate, the strength and rigidity of the second metal plate layer to which the fastening force of the fastening member is applied are increased, the bending strength is secured, and the stress applied to the resin plate layer at the fixing portion of the fastening member is alleviated. Therefore, it is possible to effectively prevent the compression failure of the end plate.

(12) In the battery module described in (10) or (11), a plurality of metal hollow column members (for example, nuts to be described later) through which fixing members (for example, bolts 52) of the fastening members are inserted through the resin plate layers. 44), one end surface of the hollow metal column member (for example, an end surface 44a described later) is in contact with the first metal plate layer, and the other end surface of the hollow metal column member (for example, an end surface 44b described later) is It is preferably in contact with the second metal plate layer.

According to (12), the metal hollow column member is arranged so as to bridge the first metal plate layer and the second metal plate layer, and the strength against compressive force in the thickness direction of the end plate is further improved. Moreover, the thickness of the resin plate layer can be easily regulated by the axial height of the metal hollow column member.

(13) In the battery module according to (12), one end face of the hollow metal pillar member is fixed to the first metal plate layer, and the other end face of the hollow metal pillar member is fixed to the second metal plate layer, Alternatively, they are preferably in contact.

By (13), the metal hollow column member is fixed in a state of bridging the first metal plate layer and the second metal plate layer, and the end plate against the force in the direction of displacement between the first metal plate layer and the second metal plate layer strength is further improved.

(14) In the battery module according to any one of (10) to (13), the fastening member is fixed to both widthwise ends of the end plate, and the second metal plate layer is fixed to both widthwise ends of the end plate. It is preferable to have a second bent portion (for example, a side bent portion 434 to be described later) bent so that the corner portion has an R shape toward the first metal plate layer.

According to (14), the contact points between the fastening members fixed to both ends in the width direction of the end plates and the end plates are the corners of the R-shaped second bent portion. The stress concentrated on the contact point can be relaxed, and the load applied to the fastening member can be reduced. Moreover, since the compressive stress acting on both end corners of the resin plate layer is relaxed by fastening the fastening member and the end plate, the creep phenomenon of the resin plate layer can be suppressed.

(15) In the end plate described in (14), the distal end portion of the second bent portion (for example, a distal end portion 434a to be described later) is the inner surface of the first metal plate layer (for example, an inner surface 41a to be described later). preferably in contact with

According to (15), when the compressive stress acts on the resin plate layer, the second bent portion functions to prevent the compression of the resin plate layer, so that the fastening member is fastened by the compression of the resin plate layer. A decrease in strength can be suppressed.

(16) In the battery module according to any one of (10) to (15), at least one of the first metal plate layer and the second metal plate layer has at least one edge in the height direction. It is preferable to have a first bent portion (for example, an upper bent portion 432 and a lower bent portion 433 to be described later) bent toward the second metal plate layer or the first metal plate layer.

Due to (16), the geometrical moment of inertia of the end plate increases, and the rigidity in the width direction of the end plate can be further improved.

(17) In the battery module described in (16), the tip portions of the first bent portions (for example, tip portions 432a and 433a, which will be described later) are located inside the second metal plate layer or the first metal plate layer. It is preferably in contact with a side surface (for example, an inner side surface 43a or 41a, which will be described later).

Due to (17), the effect of suppressing deformation in the width direction of the end plate when bending stress acts on the end plate in the width direction can be further enhanced.

(18) In the battery module described in (16) or (17), the height of both edges (for example, edges 432c and 433c to be described later) of the first bent portion in the width direction and the height of the second bent portion Directional edges (eg, edge 434c described below) are preferably joined together.

Due to (18), the end plate has a box-like outer shape, so that the rigidity of the end plate can be further improved.

(19) In the battery module according to (16) or (17), third folds are formed at both ends of the first fold in the width direction so as to overlap the surface of the second fold. It is preferable to have portions (for example, extended bent portions 432d and 433d described later), and overlapping portions of the second bent portion and the third bent portion are joined to each other.

(19) improves the rigidity of the first bent portion and the second bent portion. The rigidity of the end plate can be further improved.

(20) In the battery module according to (12) or (13), the first metal plate layer and the second metal plate layer are formed on at least both widthwise end portions of the peripheral end portion of the resin plate layer. It is preferable that a metal strut frame member (for example, strut frame members 46 and 460 to be described later) is disposed between them, and the strut frame member is integrated with the metal hollow pillar member.

(20) reinforces both ends of the resin plate layer in the width direction, prevents or suppresses compression failure of the resin plate layer, and greatly improves creep resistance. In addition, the number of parts can be reduced by integrating the support member and the hollow metal column member.

(21) In the battery module described in (20), the connection portion (for example, a connection portion 461 described later) that integrates the strut frame member and the metal hollow column member is larger than the outer diameter of the metal hollow column member. It is also preferable that the resin plate layer is formed so as to have a narrow width, and the resin of the resin plate layer enters between the support frame member and the metal hollow column member so as to sandwich the connecting portion.

Due to (21), the support frame member is prevented from slipping out of the resin plate layer in the width direction, and the bonding strength between the support frame member and the hollow metal column member and the resin plate layer can be further improved.

(22) In the battery module described in (20) or (21), the strut frame member may be arranged at the end of the entire circumference of the resin plate layer.

Due to (22), the end plate is reinforced by the strut frame member covering the entire circumference of the resin plate layer, so that the rigidity in the width direction is further improved.

(23) In the battery module according to any one of (20) to (22), it is preferable that the support frame portion is in contact with or joined to the first metal plate layer and the second metal plate layer. .

(23) can further improve the rigidity of the end plate.

(24) In the battery module according to any one of (1) to (23), an insulating plate (for example, An insulating plate 7), which will be described later, is preferably arranged.

(24) can provide insulation between the outermost battery cell and the first metal plate layer of the end plate.

(25) In a method for manufacturing an end plate according to the present invention, in a battery module (for example, a battery module 1 described later) provided with a plurality of stacked battery cells (for example, a battery cell 2 described later), the stacking direction of the battery cells Manufacture of end plates (e.g., end plates 4 described later) that are disposed at both ends of the battery cell and sandwich the entire battery cell by fixing and fastening fastening members (e.g., fastening members 5 described later) A method, wherein the fastening member is secured between a first metal plate layer (e.g., first metal plate layer 41 described below) and a second metal plate layer (e.g., second metal plate layer 43, described below). After sandwiching a plurality of metal hollow column members (for example, nuts 44 to be described later) through which members (for example, bolts 52 to be described later) are inserted, resin is placed between the first metal plate layer and the second metal plate layer. is inserted to form a resin plate layer (for example, a resin plate layer 42 to be described later).

Due to (25), the strength, rigidity, and lightness are high, and the hollow metal column member is arranged so as to bridge the first metal plate layer and the second metal plate layer, and the compressive force in the thickness direction of the end plate It is possible to obtain an end plate with further improved strength against. Moreover, the thickness of the resin plate layer can be easily regulated by the axial height of the metal hollow column member.

(26) In the method for manufacturing an end plate according to (25), one of the first metal plate layer and the second metal plate layer (for example, a second metal plate layer 43 to be described later) is provided with the While fixing one end surface (for example, an end surface 44b described later) of the metal hollow column member, the other layer of the first metal plate layer and the second metal plate layer (for example, the first metal plate layer 41 described later) ), the other end face (for example, an end face 44a described later) of the metal hollow column member is fixed or brought into contact, and the plurality of metal hollows are formed between the first metal plate layer and the second metal plate layer. It is preferable to form the resin plate layer by inserting the resin between the first metal plate layer and the second metal plate layer after sandwiching the column member.

According to (26), the metal hollow column member fixes the first metal plate layer and the second metal plate layer, and the strength against the force in the direction of displacement between the first metal plate layer and the second metal plate layer is further improved. It is possible to easily obtain a finished end plate.

(27) In the end plate manufacturing method according to (25) or (26), after the plurality of metal hollow column members are sandwiched between the first metal plate layer and the second metal plate layer , the surfaces of the first metal plate layer and the second metal plate layer that are in contact with the resin to be inserted are roughened, or metal-resin bonding film treatment is performed to chemically bond the metal and the resin, and then, Preferably, the resin plate layer is formed by inserting the resin between the first metal plate layer and the second metal plate layer.

Due to (27), the adhesion between the first metal plate layer and the resin plate layer and between the second metal plate layer and the resin plate layer is improved, and the slippage between the end plate layers is suppressed. , strength and rigidity can be easily obtained.

(28) In the end plate manufacturing method according to any one of (25) to (27), the outer surface of the second metal plate layer after the resin plate layer is formed (for example, the outer surface 43b described later) ) is preferably laminated with a carbon fiber reinforced plastic plate layer (for example, a CFRP plate layer 45 described later).

(28) makes it possible to obtain an end plate with increased strength and rigidity.

(29) In a method for manufacturing an end plate according to the present invention, in a battery module (for example, a battery module 1 described later) provided with a plurality of stacked battery cells (for example, a battery cell 2 described later), the stacking direction of the battery cells End plates (for example, end plates 4, 4A to 4A to 4I), wherein a plurality of metal hollow columns through which fixing members (for example, bolts 52 to be described later) of the fastening member are inserted through the surface of the metal plate layer (for example, the second metal plate layer 43 to be described later). After placing the member (for example, nut 44), a resin plate layer (for example, resin plate layer 42 to be described later) in which the metal hollow column member is embedded is formed on the surface of the metal plate layer, and then separated. The second metal plate layer (for example, a first metal plate layer 41 described later) is placed on the surface of the resin plate layer, and pressurized and heated to remelt the resin plate layer. A metal plate layer is bonded to the resin plate layer.

(29) makes it possible to simplify the mold for forming the resin plate layer, so that the cost of the end plate can be reduced. Moreover, since there is no need to insert a resin, there is no limitation on the resin thickness due to the fluidity of the resin, and a decrease in the strength of the resin plate layer due to welding can be avoided.

ADVANTAGE OF THE INVENTION According to this invention, the strength, rigidity is high, and the manufacturing method of the battery module provided with a lightweight end plate and its end plate can be provided.

1 is an overall perspective view of a battery module according to one embodiment of the present invention; FIG. FIG. 2 is an exploded perspective view of the battery module shown in FIG. 1; FIG. 2 is an overall perspective view showing a first embodiment of an end plate used in the battery module shown in FIG. 1; 4 is a cross-sectional view taken along line AA in FIG. 3; FIG. FIG. 4 is an exploded perspective view of the end plate shown in FIG. 3; 4A and 4B are views for explaining a method of manufacturing the end plate shown in FIG. 3; FIG. 4A and 4B are views for explaining a method of manufacturing the end plate shown in FIG. 3; FIG. 4A and 4B are views for explaining a method of manufacturing the end plate shown in FIG. 3; FIG. FIG. 3 is an overall perspective view showing a second embodiment of an end plate used in the battery module shown in FIG. 1; FIG. 10 is a cross-sectional view taken along line BB in FIG. 9; FIG. 10 is an exploded perspective view of the end plate shown in FIG. 9; FIG. 5 is an overall perspective view showing a third embodiment of an end plate used in the battery module according to the present invention; FIG. 13 is an exploded perspective view of the end plate shown in FIG. 12 as viewed from the side of the stacking surface with the battery cells; 13 is a side view of the end plate shown in FIG. 12; FIG. 13 is a plan view illustrating the relationship between the end plate and the fastening member shown in FIG. 12; FIG. It is a side view which shows another aspect of the end plate which concerns on 3rd Embodiment. FIG. 11 is an overall perspective view showing a fourth embodiment of an end plate used in the battery module according to the present invention; FIG. 11 is an overall perspective view showing a fifth embodiment of an end plate used in the battery module according to the present invention; FIG. 11 is an exploded perspective view showing a sixth embodiment of the end plate used in the battery module according to the present invention; FIG. 20 is a cross-sectional view showing a main part of the end plate shown in FIG. 19; FIG. 11 is an exploded perspective view showing a seventh embodiment of an end plate used in the battery module according to the present invention; FIG. 11 is an overall perspective view showing an eighth embodiment of an end plate used in a battery module according to the present invention; 23 is a plan view of the end plate shown in FIG. 22; FIG. FIG. 4 is an explanatory diagram of a solid structure for trial calculation of a geometric moment of inertia per cross-sectional area; FIG. 4 is an explanatory diagram of a hollow structure for trial calculation of a geometrical moment of inertia per cross-sectional area; FIG. 4 is an explanatory diagram of a hollow structure for trial calculation of a three-point bending deflection amount; FIG. 4 is an explanatory diagram of a hollow structure for trial calculation of a three-point bending deflection amount; FIG. 4 is an explanatory diagram of a solid structure for trial calculation of a three-point bending deflection amount; 4 is a graph illustrating the relationship between the amount of deflection and the weight of a hollow structure and a solid structure; FIG. 21 is an overall perspective view showing a ninth embodiment of an end plate used in a battery module according to the present invention; 28 is a plan view of the end plate shown in FIG. 27; FIG. FIG. 21 is a diagram for explaining the bending moment distribution of the end plate according to the ninth embodiment; FIG. 10 is an overall perspective view showing a tenth embodiment of an end plate used in a battery module according to the present invention; 31 is an exploded perspective view of the end plate shown in FIG. 30 as seen from the rear side; FIG. FIG. 31 is a cross-sectional view taken along line CC in FIG. 30; FIG. 21 is a front view showing a resin plate layer of an end plate according to an eleventh embodiment used in the battery module according to the present invention; FIG. 10 is a diagram illustrating another embodiment of a method for manufacturing an end plate used in the battery module according to the present invention; FIG. 10 is a diagram illustrating another embodiment of a method for manufacturing an end plate used in the battery module according to the present invention; FIG. 29 is a diagram illustrating a method of manufacturing the end plate shown in FIGS. 27 and 28; FIG. It is a figure which shows the experimental method of giving a stress to the endplate based on the Example of this invention. FIG. 5 is a diagram showing analysis results when stress is applied to the end plate according to the example of the present invention; 8 is a diagram showing an experimental method for applying stress to the end plate according to Comparative Example 1. FIG. FIG. 10 is a diagram showing analysis results when stress is applied to the end plate according to Comparative Example 1; FIG. 10 is a diagram showing analysis results when stress is applied to the end plate according to Comparative Example 2;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<Overall Configuration of Battery Module>
FIG. 1 is an overall perspective view of a battery module according to one embodiment of the present invention, and FIG. 2 is an exploded perspective view of the battery module shown in FIG.
The battery module 1 mainly includes a plurality of battery cells 2 , a pair of end plates 4 and fastening members 5 . In addition, in the directions shown in the drawing, the D1 direction is the direction along the stacking direction of the plurality of battery cells 2 and indicates the length direction of the battery module 1 . The D2 direction is a direction orthogonal to the stacking direction of the plurality of battery cells 2 and indicates the width direction of the battery module 1 . The D3 direction is a direction orthogonal to the stacking direction of the plurality of battery cells 2 and indicates the height direction of the battery module 1 .

As shown in FIG. 2, the battery cell 2 houses an electrode body (not shown) inside a rectangular parallelepiped cell case 20 made of, for example, aluminum or an aluminum alloy. The upper surface of the battery cell 2 is covered. A positive electrode terminal 21 and a negative electrode terminal 22 protrude from the upper surface of the battery cell 2 . The plurality of battery cells 2 are arranged with the surface having the positive electrode terminal 21 and the negative electrode terminal 22 facing upward along the D3 direction in the drawing, and are arranged by stacking a plurality of cells along the D1 direction. An insulating plate 7 is sandwiched between the adjacent battery cells 2, 2 to insulate the adjacent battery cells 2, 2 from each other.

The battery cells 2, 2 adjacent along the D1 direction are oriented such that the positive terminals 21 and the negative terminals 22 alternate. A plate-shaped bus bar 3 electrically connects the positive terminal 21 and the negative terminal 22 of the adjacent battery cells 2 , 2 . As a result, all of the battery cells 2 stacked in multiple layers are connected in series. In the battery cells 2, 2 arranged at both ends, the positive terminal 21 or the negative terminal 22, to which the bus bar 3 is not provided, is provided with wiring harnesses 6, 6, respectively.

The end plates 4 are arranged at both ends in the stacking direction (D1 direction) of the plurality of stacked battery cells 2 . That is, the pair of end plates 4, 4 are arranged outside the battery cells 2, 2 arranged at both ends, respectively, and sandwich the plurality of battery cells 2 as a whole. A specific structure of the end plate 4 will be described later.

The fastening members 5 are metal bands called bind bars or the like, and are arranged on both side surfaces parallel to the stacking direction (D1 direction) of the battery cells 2 . Both ends of the fastening member 5 in the length direction (D1 direction) are bent toward the inside (battery cell 2 side) at right angles in the same direction. integrally has

The fastening member 5 has fixed pieces 51, 51 at both ends thereof, which are in contact with the outer side surfaces 4a at both ends in the width direction (D2 direction) of the end plate 4, respectively. 4 is fixed. In this embodiment, one fixing piece 51 is fixed to the end plate 4 by three bolts 52 arranged along the height direction (D3 direction). As a result, a restraining force is applied to the plurality of battery cells 2 in the stacking direction (D1 direction), and expansion due to charging and discharging of the battery cells 2 is suppressed. In this embodiment, each bolt 52 is screwed through a collar 53 arranged on the surface of the end plate 4 .

<First Embodiment of End Plate>
Next, a first embodiment of the end plate 4 will be described with reference to FIGS. 3 to 5. FIG. 3 is an overall perspective view showing one embodiment of an end plate used in the battery module shown in FIG. 1. FIG. 4 is a cross-sectional view taken along line AA in FIG. 3. FIG. 5 is an exploded perspective view of the end plate shown in FIG. 3. FIG.
The end plate 4 shown in this embodiment has a three-layer structure in which a first metal plate layer 41/resin plate layer 42/second metal plate layer 43 are laminated in this order from the battery cell 2 side.

The first metal plate layer 41 and the second metal plate layer 43 are plate-like members each formed of a metal material such as iron or aluminum in a rectangular shape similar to the side shape of the battery cell 2 . Therefore, the portion of the end plate 4 to which the fastening member 5 is fixed is not the resin plate layer 42 but the surface of the second metal plate layer 43 made of a metal material. Therefore, the stress applied to the resin plate layer 42 at the portion where the fastening member 5 is fixed by the bolt 52 is alleviated, and the compression failure of the end plate 4 can be prevented or suppressed.

In the present embodiment, the first metal plate layer 41 and the second metal plate layer 43 are, for example, aluminum for the first metal plate layer 41 arranged on the battery cell 2 side, and a second metal plate layer arranged on the outside. Since the plate layer 43 is made of iron or the like, the second metal plate layer 43 to which the fastening member 5 is fixed has higher rigidity than the first metal plate layer 41 . That is, the rigidity is in the order of second metal plate layer 43 >first metal plate layer 41 >resin plate layer 42 . As a result, in the end plate 4 , the strength and rigidity of the second metal plate layer 43 to which the fastening force of the fastening member 5 is applied are enhanced, and the bending strength is ensured. is alleviated, the compression failure of the end plate 4 can be effectively prevented or suppressed.

On the other hand, the resin plate layer 42 is made of a resin material such as polypropylene (PP), polystyrene (PS), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), or the like. It is formed in a rectangular shape similar to 43 . The resin plate layer 42 is insert-molded between the first metal plate layer 41 and the second metal plate layer 43 using a resin material. That is, the melted resin that forms the resin plate layer 42 is inserted between the first metal plate layer 41 and the second metal plate layer 43 to adhere to the metal plate layers 41 and 43 . After that, the resin is cooled and hardened, thereby forming a joint portion between the first metal plate layer 41 and the second metal plate layer 43 to join and integrate them. Thereby, the resin plate layer 42 is formed integrally with the first metal plate layer 41 and the second metal plate layer 43 .

Since the resin plate layer 42 has a lower density than the first metal plate layer 41 and the second metal plate layer 43, the weight of the end plate 4 is reduced even with the three-layer structure. On the other hand, since the resin plate layer 42 has low rigidity, it is necessary to increase the thickness of the resin plate layer 42 in order to improve the strength and rigidity of the end plate 4 . Therefore, the end plate 4 has a structure in which the thickness of the resin plate layer 42 is greater than the thickness of each of the first metal plate layer 41 and the second metal plate layer 43 .

The thickness of the resin plate layer 42 will be further explained.
The combination of two kinds of metals and resin is such that the coefficients of linear expansion of each metal are α _M1 and α _M2 (where α _M1 <α _M2 ), the thickness of the resin is L ₀ , the tensile shear strength is τ, Let G _P be the transverse modulus of elasticity, X be the width of the end plate 4, and ΔT (=T ₂ −T ₁ ) be the temperature difference.
τ≧ _GP ×( _αM2 − _αM1 )×ΔT×X/2L ₀
L ₀ ≥ G _P × (α _M2 - α _M1 ) × ΔT × X/2τ
must be a combination of metal, resin material, and resin thickness that satisfies Note that ΔT is assumed to be 60°C or less, which encompasses the operating temperature range of automobiles -40°C to room temperature to 60°C.

A resin sandwiched between two kinds of metals having different coefficients of linear expansion receives shear stress from each metal due to the thermal expansion of the material. If the thickness _L0 of the resin is large, the breakage can be prevented by stress relaxation. Shear strain υ and shear stress τ _P generated in the resin are
ν=λ/L ₀
τ _P = _GP v
becomes. At this time, the shear displacement λ is given by the shift amount of the metal with a small linear expansion coefficient between the temperature T1 and the temperature T2 as _a , and the shift amount of the metal with a large linear expansion coefficient as _b .
λ=ba
= _αM2 ×ΔT×X/2− _αM1 ×ΔT×X/2
= (α _M2 - α _M1 ) x ΔT x X/2
Since
τ= _GP ×( _αM2 − _αM1 )×ΔT×X/2L ₀
becomes. If this shear stress is smaller than the shear strength τ of the resin, the resin will not be destroyed and the function of the end boot can be ensured.

Therefore,
τ≧τ _P = _GP ×(α _M2 −α _M1 )×ΔT×X/2L ₀
L ₀ ≥ G _P × (α _M2 - α _M1 ) × ΔT × X/2τ
The function of the end plate is established by selecting a metal, a resin material, and a resin thickness that satisfy the above. The specific thickness of each layer 41, 42, 43 of the end plate 4 shown in the present embodiment is not limited at all. 14 mm, and the second metal plate layer 43 can be 2 mm.

Since the end plate 4 configured in this manner effectively laminates the resin plate layer 42 having a large thickness between the first metal plate layer 41 and the second metal plate layer 43, the first metal plate layer The strength and rigidity of the end plate 4 can be ensured by the plate layer 41 and the second metal plate layer 43 . In order to ensure the necessary strength and rigidity, the end plate 4 does not increase the thickness of the first metal plate layer 41 and the second metal plate layer 43, and the thickness of the relatively low-density resin plate layer 42 is reduced. Since the thickness is larger than the respective thicknesses of the first metal plate layer 41 and the second metal plate layer 43, the moment of inertia of area can be increased and the weight can be reduced. As a result, the battery module 1 having the end plates 4 that are lightweight while having high strength and rigidity can be configured.

Moreover, in the end plate 4, the thickness of the resin plate layer 42 is made larger than the thickness of each of the first metal plate layer 41 and the second metal plate layer 43, so that the first metal plate layer 41 and the second metal plate layer 43 The stress generated by the difference in thermal expansion between the metal plate layer 43 and the resin plate layer 42 can be relieved by deformation of the resin. Therefore, the battery module 1 in which the plurality of battery cells 2 are stably held between the pair of end plates 4, 4 can be constructed.

In order to improve adhesion between the first metal plate layer 41 and the resin plate layer 42 and between the second metal plate layer 43 and the resin plate layer 42, the first metal plate layer 41 and the second metal The plate layer 43 preferably has a surface roughening treatment or a metal-resin bonding film treatment for chemically bonding metal and resin to the surface in contact with the resin plate layer 42 . The roughening treatment allows the resin material inserted between the first metal plate layer 41 and the second metal plate layer 43 to become solidified in each of the first metal plate layer 41 and the second metal plate layer 43 by a so-called anchor effect. Since the end plate 4 sticks so as to bite into the surface, the strength in the direction of displacement between the layers of the end plate 4 is further improved, and the strength and rigidity of the end plate 4 are further improved. In addition, by the metal-resin bonding film treatment, the bonding film chemically bonds the metal and the resin, and an effect similar to that of the roughening treatment can be obtained.

A specific roughening treatment means is not particularly limited, and a known treatment capable of forming nanometer-scale unevenness on the surface in contact with the resin plate layer 42 can be used. Examples include surface roughening treatment by immersion in an unevenness forming liquid (for example, chemical etching solution such as hydrohalic acid such as hydrochloric acid, sulfurous acid, sulfuric acid, etc.), and mechanical surface roughening treatment such as sandblasting. In addition, the specific means of metal-resin bonding coating treatment is not particularly limited, and at least the surface in contact with the resin plate layer 42 is known to be capable of forming a nanometer-scale coating having high chemical reactivity with both the metal and the resin. can be used. For example, solution treatment using triazinethiol or the like is exemplified.

As shown in FIGS. 4 and 5, a plurality of nuts 44 are provided inside the end plate 4 of this embodiment. The nut 44 is a metal hollow column member through which the bolt 52 for fixing the fastening member 5 is inserted. A female thread (not shown) that is screwed with the bolt 52 is formed on the inner peripheral surface of the nut 44 . As shown in FIG. 3, through holes 431 for inserting the bolts 52 into the nuts 44 are formed in the second metal plate layer 43, which is the outer surface 4a of the end plate 4, at positions corresponding to the respective nuts 44. ing. Each through hole 431 is smaller than the outer diameter of the nut 44 and equal to or larger than the inner diameter of the nut 44 . Note that FIG. 5 shows a through hole 421 formed by the nut 44 at a portion of the resin plate layer 42 where the nut 44 is arranged. The through hole 421 is formed by insert-molding the resin plate layer 42 between the first metal plate layer 41 and the second metal plate layer 43, as will be described later.

The nut 44 is arranged inside the resin plate layer 42 and constitutes a part of the resin plate layer 42 . Specifically, the nuts 44 are provided in the resin plate layer 42 corresponding to both ends in the width direction (D2 direction) of the end plate 4 with which the fixed pieces 51 of the fastening member 5 abut. are arranged in groups of three along the One end surface 44 a of each nut 44 is in contact with the first metal plate layer 41 . Also, the other end surface 44 b of each nut 44 is in contact with the second metal plate layer 43 . Therefore, the nut 44 is arranged to bridge the first metal plate layer 41 and the second metal plate layer 43 in the end plate 4 . As a result, when the end plate 4 is compressed in the thickness direction between the battery cell 2 and the fastening member 5 due to the expansion of the battery cell 2 , the nut 44 allows the compression force to act on the resin plate layer 42 . This prevents the resin plate layer 42 from being crushed by compression. Therefore, the strength against the compressive force in the thickness direction of the end plate 4 can be further improved. Moreover, the thickness of the resin plate layer 42 can be easily regulated by the height of the nut 44 in the axial direction.

Each end surface 44a, 44b of the nut 44 is fixed to the first metal plate layer 41 and the second metal plate layer 43, respectively, or one of the end surfaces 44a or 44b of the nut 44 is fixed to the first metal plate. It is preferable that it is fixed to the layer 41 or the second metal plate layer 43 and the other end surface 44b or 44a is in contact with the second metal plate layer 43 or the first metal plate layer 41 . As a result, the nut 44 fixes the first metal plate layer 41 and the second metal plate layer 43 in a bridging state on at least one of the end faces 44a or 44b. The strength of the end plate 4 against force in the direction of deviation from the layer 43 is further improved.

Examples of means for fixing the end surfaces 44a and 44b of the nut 44 to the first metal plate layer 41 and the second metal plate layer 43 include welding and adhesion using an epoxy-based adhesive.

The end plate 4 configured in this way is oriented so that the first metal plate layer 41 side faces the battery cell 2 side, and as shown in FIG. are placed in contact with both ends of the At this time, since the metals of the outermost battery cells 2, 2 and the end plates 4, 4 are opposed to each other, the outermost battery cell An insulating plate 7 is also arranged between 2,2 and each end plate 4,4.

Next, an embodiment of a method for manufacturing the end plate 4 having the above configuration will be described with reference to FIGS. 6 to 8. FIG.
First, as shown in FIG. 6, after forming a first metal plate layer 41 and a second metal plate layer 43 into a predetermined rectangular plate shape, one of them, in this embodiment, the second metal plate layer A plurality of nuts 44 are secured to 43, respectively. Specifically, one end surface 44b of each nut 44 is fixed to the inner surface 43a of the second metal plate layer 43 by welding, for example. A plurality of through holes 431 are formed in advance at predetermined positions in the second metal plate layer 43 . Each nut 44 is fixed substantially concentrically to the through-hole 431 . In this way, fixing the nut 44 to the second metal plate layer 43 first allows the through hole 431 to be used for positioning rather than fixing the nut 44 to the first metal plate layer 41 first. The fixing work of the nut 44 can be easily performed.

Next, as shown in FIG. 7, the first metal plate layer 41 is fixed so as to cover the nut 44 fixed to the second metal plate layer 43 . Specifically, the inner surface 41a of the first metal plate layer 41 is fixed to the other end surface 44a of each nut 44 by, for example, welding. As a result, a plurality of nuts 44 are sandwiched between the first metal plate layer 41 and the second metal plate layer 43, and the first metal plate layer 41 and the second metal plate layer 43 are bridged by the nuts 44 and integrated. A monolithic structure is obtained that is secured to the

Next, for the integral structure constructed as described above, the surfaces in contact with the resin for forming the resin plate layer 42 to be described later, that is, the inner surface 41a of the first metal plate layer 41 and the second metal plate The inner surface 43a of the layer 43 and the outer peripheral surface of each nut 44 are subjected to roughening treatment or metal-resin bonding coating treatment.

After roughening treatment or metal-resin bonding film treatment, as shown in FIG. The resin plate layer 42 is insert-molded between the metal plate layer 43 and the metal plate layer 43 . As a result, the end plate 4 having a three-layer structure in which the first metal plate layer 41, the resin plate layer 42, and the second metal plate layer 43 are laminated and integrated is obtained. According to this method, the strength and rigidity are high, and the nut 44 is arranged so as to bridge the first metal plate layer 41 and the second metal plate layer 43, so that the thickness of the end plate 4 It is possible to easily obtain an end plate 4 with further improved strength against directional compressive force. Moreover, the thickness of the resin plate layer 42 can be easily defined by the height of the nut 44 in the axial direction.

Further, by fixing the nut 44 to the first metal plate layer 41 and the second metal plate layer 43 as in the present embodiment, the shift direction of the first metal plate layer 41 and the second metal plate layer 43 can be changed. It is possible to easily obtain the end plate 4 with further improved strength against the force of .

Furthermore, since the surfaces of the first metal plate layer 41 and the second metal plate layer 43 that come into contact with the resin to be inserted are roughened or treated with a metal-resin bonding coating, the first metal plate layer 41 and the resin plate layer 42 and between the second metal plate layer 43 and the resin plate layer 42 , the adhesion between the end plates 4 is improved, and inter-layer slippage of the end plate 4 is suppressed. Therefore, it is possible to easily obtain the end plate 4 with enhanced strength and rigidity.

<Second Embodiment of End Plate>
Next, a second embodiment of the end plate 4 will be described with reference to FIGS. 9 to 11. FIG.
9 is an overall perspective view showing a second embodiment of an end plate used in the battery module shown in FIG. 1. FIG. 10 is a cross-sectional view taken along line BB in FIG. 9. FIG. 11 is an exploded perspective view of the end plate shown in FIG. 9. FIG. In FIGS. 9 to 11, parts having the same reference numerals as those of the end plate 4 of the first embodiment have the same configuration. .
In the end plate 4A of the second embodiment, a first metal plate layer 41/resin plate layer 42/second metal plate layer 43/CFRP (carbon fiber reinforced plastic) plate layer 45 are laminated in this order from the battery cell 2 side. It has a four-layer structure. Therefore, looking only at the laminated structure, the end plate 4A has a structure in which one CFRP plate layer 45 is added to the outer surface 43b of the second metal plate layer 43 of the end plate 4 of the first embodiment. there is

The CFRP plate layer 45 is a rectangular plate-like member similar to the second metal plate layer 43 . The CFRP plate layer 45 is bonded to the outer surface 43b of the second metal plate layer 43 with, for example, an epoxy-based adhesive. Through-holes 451 through which the bolts 52 are inserted are formed in the CFRP plate layer 45 at positions corresponding to the through-holes 431 of the second metal plate layer 43 .

The CFRP plate layer 45 is laminated on the second metal plate layer 43 to distribute the load applied to the CFRP plate layer 45 to the second metal plate layer 43 . CFRP is generally expensive, but since the CFRP plate layer 45 can be made thin, an increase in cost can be suppressed.

In general, CFRP has high strength and high rigidity. Therefore, in the end plate 4A, even if the rigidity of the second metal plate layer 43 is lower than the rigidity of the first metal plate layer 41, the fastening force of the fastening member 5 is The strength and rigidity of the outermost portion of the end plate 4A to which the load is applied can be increased, and sufficient bending strength can be ensured. Therefore, the rigidity of each layer of the end plate 4A can be in the order of CFRP plate layer 45 >first metal plate layer 41 >second metal plate layer >resin plate layer 42 . As a result, the bending strength of the first metal plate layer 41, which receives stress when the battery cell 2 expands, can be increased, so that the strength and rigidity of the end plate 4A can be further increased.

As shown in FIG. 8, the end plate 4A configured in this manner is a laminated structure having a three-layer structure by injecting a resin material between the first metal plate layer 41 and the second metal plate layer 43. can be obtained by adhering a separately manufactured CFRP plate layer 45 to the outer surface 43b of the second metal plate layer 43 after obtaining the above.

<Third Embodiment of End Plate>
Next, a third embodiment of the end plate will be described with reference to FIGS. 12 to 14. FIG.
FIG. 12 is an overall perspective view showing a third embodiment of the end plate used in the battery module according to the invention. In FIG. 12, the state in which the second metal plate layer 43 is developed is also shown by a chain double-dashed line. 13 is an exploded perspective view of the end plate shown in FIG. 12 as viewed from the side of the stacking surface with the battery cells. 14 is a side view of the end plate shown in FIG. 12; FIG. Parts having the same reference numerals as those of the end plate 4 of the first embodiment have the same configuration. The description of the first embodiment is used as long as there is no particular difference, and is omitted here.

The end plate 4B of the second embodiment has a three-layer structure in which the first metal plate layer 41/the resin plate layer 42/the second metal plate layer 43 are laminated in this order from the battery cell 2 side. It is the same as the end plate 4 in form. However, this end plate 4B differs from the end plate 4 of the first embodiment in that it has a bent portion formed by bending toward the first metal plate layer 41 at the end of the second metal plate layer 43. .

Specifically, the second metal plate layer 43 has an upper bent portion 432 at the upper end portion in the height direction (D3 direction) of the metal plate layer body 430, and the height direction (D3 direction) of the metal plate layer body 430. direction) has a lower bent portion 433 . The upper bent portion 432 and the lower bent portion 433 are rectangular plate pieces integrally projecting upward and downward from both ends of the metal plate layer main body 430 in the height direction. It is formed by bending at a substantially right angle toward . The width dimension (dimension in the D2 direction) of the upper bent portion 432 and the lower bent portion 433 is slightly smaller than the width dimensions of the first metal plate layer 41 and the resin plate layer 42 . The upper bent portion 432 and the lower bent portion 433 correspond to the "first bent portion" of the present invention.

The second metal plate layer 43 has side bent portions 434, 434 at both ends in the width direction (D2 direction) of the rectangular metal plate layer main body 430 facing the resin plate layer 42, respectively. The side bent portions 434 , 434 are rectangular plate pieces integrally projecting sideways from both ends in the width direction of the metal plate layer main body 430 , and extend substantially perpendicularly toward the first metal plate layer 41 . It is formed by being folded. The side bent portions 434, 434 are formed by bending the second metal plate layer 43, so that the bent corner portions 435, 435 have an R shape (a curved surface along the bending direction). The height dimension (dimension in the D3 direction) of the side bent portion 434 is slightly smaller than the height dimension of the first metal plate layer 41 and the resin plate layer 42 . This side bent portion 434 corresponds to the "second bent portion" of the present invention.

In the end plate 4B according to the third embodiment, the upper bent portion 432 and the lower bent portion 433 extend along the width direction (D2 direction) of the second metal plate layer 43 (end plate 4B). Therefore, the upper bent portion 432 and the lower bent portion 433 can function as reinforcing ribs in the width direction of the second metal plate layer 43 . Therefore, the upper bent portion 432 and the lower bent portion 433 improve the geometrical moment of inertia of the end plate 4B as compared to the end plate 4 according to the first embodiment, which also has a three-layer structure. As a result, the end plate 4B further improves in strength and rigidity in the width direction. Since this effect can be obtained only by integrally forming the upper bent portion 432 and the lower bent portion 433 on the second metal plate layer 43, it is possible to increase the number of layers of the end plate 4B or add other structural materials. You don't have to. Therefore, the weight reduction of the end plate 4B is not hindered.

As shown in FIG. 14 , the tip 432 a of the upper bent portion 432 and the tip 433 a of the lower bent portion 433 are in contact with the inner surface 41 a of the first metal plate layer 41 facing the second metal plate layer 43 . is preferred. As a result, when bending stress acts in the width direction (D2 direction) of the end plate 4B due to the expansion of the battery cell 2, the upper bent portion 432 and the lower bent portion 433 are supported by the inner surface 41a of the first metal plate layer 41. Since the force that tends to deform the second metal plate layer 43 is blocked, the effect of suppressing deformation in the width direction of the end plate 4B can be further enhanced. The tip portions 432 a and 433 a do not necessarily have to be joined to the inner surface 41 a of the first metal plate layer 41 .

15 is a plan view illustrating the relationship between the end plate 4B and the fastening members 5, 5. FIG. In the end plate 4B, the fixed pieces 51, 51 of the fastening members 5, 5 are fixed to both ends in the width direction (D2 direction) of the second metal plate layer 43 by bolts 52 (see FIGS. 1 and 2). . Here, when the pressing force due to the expansion of the battery cell 2 acts on the end plate 4B as indicated by the white arrow in the figure, the reaction force is applied to the fastening members 5, 5 via the fixed pieces 51, 51. As a result, the fastening members 5, 5 exert a tensile force on both ends of the end plate 4B in the direction indicated by the solid line arrows in the figure. At this time, stress concentrates on the contact points between the fastening members 5, 5 or the fixed pieces 51, 51 and the end plate 4B, which may generate a load.

However, according to the end plate 4B, the corners 435, 435 of the second metal plate layer 43 have an R shape by bending the side bent portions 434, 434, so that the corners 435, 435 are Even if it comes into contact with the fastening members 5, 5 or the fixed pieces 51, 51, stress concentration at the contact points is alleviated. As a result, the load applied to the fastening members 5, 5 or the fixed pieces 51, 51 is reduced, and damage to the fastening members 5, 5 or the fixed pieces 51, 51 is also suppressed. Moreover, since the contact points between the corners on both ends of the resin plate layer 42 and the second metal plate layer 43 also have an R shape, the compressive stress applied to the corners on both ends of the resin plate layer 42 is also alleviated. Creepability is also improved.

As shown in FIG. 14, it is preferable that tip portions 434a, 434a of the side bent portions 434, 434 are also in contact with the inner surface 41a of the first metal plate layer 41. As shown in FIG. When the compressive stress acts on the resin plate layer 42, the side bent portions 434, 434 function to prevent the resin plate layer 42 from being compressed. A decrease in the fastening force of 5 can be suppressed. The tip portions 434a, 434a do not necessarily have to be joined to the inner surface 41a of the first metal plate layer 41 either.

12 and 13, a resin injection hole 436 is provided in the second metal plate layer 43. As shown in FIG. Since this end plate 4B has bent portions 432, 433, 434, and 434 in the upper, lower, left, and right directions, respectively, the first metal plate layer 41 and the second metal plate layer 41 are different than the end plates 4, 4A according to the first and second embodiments. This is because it is difficult to inject the resin forming the resin plate layer 42 between the two metal plate layers 43 from the side. The resin injection hole 436 is located at the center of the second metal plate layer 43, specifically, at the center of the metal plate layer main body 430 of the second metal plate layer 43 in the width direction (D2 direction) as shown in FIG. , and the central portion of the metal plate layer main body 430 in the height direction (D3 direction). Therefore, the molten resin injected between the first metal plate layer 41 and the second metal plate layer 43 from the resin injection hole 436 spreads evenly in the vertical and horizontal directions from the resin injection hole 436. It is possible to form a homogeneous resin plate layer 42 . Moreover, by arranging the resin injection hole 436 in the central portion of the second metal plate layer 43, imbalance of stress applied to the second metal plate layer 43 is also prevented.

In addition, in the end plate 4</b>B according to the third embodiment, the upper bent portion and the lower bent portion may be provided in the first metal plate layer 41 . That is, as shown in FIG. 16, the first metal plate layer 41 has an upper bent portion 411 that is bent at a substantially right angle toward the second metal plate layer 43 at the upper end portion in the height direction (D3 direction). However, the lower end portion may have a lower bent portion 412 that is bent at a substantially right angle toward the second metal plate layer 43 . In this case, the tip 411 a of the upper bent portion 411 and the tip 412 a of the lower bent portion 412 of the first metal plate layer 41 also face the inner surface 43 a of the second metal plate layer 43 facing the first metal plate layer 41 . may be in contact with This also provides the same effect as when the upper bent portion 432 and the lower bent portion 433 are formed in the second metal plate layer 43 .

In the end plate 4B, although not shown, for example, the first metal plate layer 41 is provided with either the upper bent portion 411 or the lower bent portion 412, and the second metal plate layer 43 is provided with the lower bent portion 433 or the upper bent portion. Either one of the portions 432 may be provided. Furthermore, the end plate 4B may be provided with only one of the upper bent portion 411 or 432 and the lower bent portion 412 or 433, although the moment of inertia of area is slightly inferior.

Furthermore, although not shown, a CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 of the end plate 4B, similarly to the end plate 4A according to the second embodiment.

<Fourth Embodiment of End Plate>
Next, a fourth embodiment of the end plate will be described with reference to FIG. 17. FIG. FIG. 17 is an overall perspective view showing a fourth embodiment of the end plate used in the battery module according to the invention. In FIG. 17, the state in which the second metal plate layer 43 is unfolded is also indicated by a chain double-dashed line. Parts having the same reference numerals as those of the end plates 4 and 4B of the first and third embodiments have the same configuration. The descriptions of the first and third embodiments are used as long as there is no particular difference, and are omitted here.

This end plate 4C is the same as the end plate 4B according to the third embodiment in that the second metal plate layer 43 has an upper bent portion 432, a lower bent portion 433, and side bent portions 434, 434. FIG. However, the upper bent portion 432 of the second metal plate layer 43 has extension portions 432b and 431b that slightly protrude in both directions of the width direction (D2 direction), and the lower bent portion 433 The extensions 433b, 433b slightly projecting in both directions, and the side bent portions 434 of the second metal plate layer 43 have extensions 434b, 434b slightly projecting in both directions of the height direction (D3 direction). is different from the end plate 4B according to the third embodiment.

When the upper bent portion 432, the lower bent portion 433, and the side bent portions 434, 434 are bent toward the first metal plate layer 41 at substantially right angles, the extension portions 432b, 433b, and 434b are bent at respective ends. The edges are provided so as to touch or be close to each other. That is, when the upper bent portion 432 and the side bent portions 434, 434 are respectively bent, both edges 432c, 432c in the width direction (D2 direction) of the upper bent portion 432 and the heights of the side bent portions 434, 434 The upper edges 434c, 434c in the vertical direction (D3 direction) are in contact with or close to each other. Further, when the lower bent portion 433 and the side bent portions 434, 434 are respectively bent, both edges 433c, 433c in the width direction (D2 direction) of the lower bent portion 433 and the heights of the side bent portions 434, 434 The lower edges 434c, 434c in the vertical direction (D3 direction) are in contact with or close to each other.

Edges 432c, 433c, 434c that are in contact with or close to each other are joined together. As a result, joints 437 are formed at the four corners of the end plate 4C. Joining can be performed, for example, by welding or gluing with an adhesive.

According to the end plate 4</b>C, the upper bent portion 432 and the side bent portion 434 and the lower bent portion 433 and the side bent portions 434 and 434 are respectively joined by the joint portions 437 . The outer shape of the end plate 4C with the second metal plate layer 43 becomes a box shape, and the rigidity of the end plate 4C can be further improved.

In the case of the end plate 4C according to the fourth embodiment as well, the upper bent portion and the lower bent portion may be provided in the first metal plate layer 41 as in the end plate 4B according to the third embodiment. In this case, an extension is provided on the first metal plate layer 41 side. Also, the first metal plate layer 41 is provided with either the upper bent portion 411 or the lower bent portion 412, and the second metal plate layer 43 is provided with either the lower bent portion 433 or the upper bent portion 432. good too. Furthermore, the end plate 4C may be provided with only one of the upper bent portion 411 or 432 and the lower bent portion 412 or 433, although the moment of inertia of area is slightly inferior.

Furthermore, although not shown, a CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 of the end plate 4C, similarly to the end plate 4A according to the second embodiment.

<Fifth Embodiment of End Plate>
Next, a fifth embodiment of the end plate will be described with reference to FIG. FIG. 18 is an overall perspective view showing a fifth embodiment of the end plate used in the battery module according to the invention. In FIG. 18, the state in which the second metal plate layer 43 is developed is also indicated by a chain double-dashed line. Parts having the same reference numerals as those of the end plates 4 and 4B of the first and third embodiments have the same configuration. The descriptions of the first and third embodiments are used as long as there is no particular difference, and are omitted here.

This end plate 4D is also the same as the end plate 4B according to the third embodiment in that the second metal plate layer 43 has an upper bent portion 432, a lower bent portion 433, and side bent portions 434, 434. However, the upper bent portion 432 of the second metal plate layer 43 has extended bent portions 432d, 432d that protrude greatly in both directions of the width direction (D2 direction), and the lower bent portion 433 has a width direction (D2 direction). The end plate 4B differs from the end plate 4B according to the third embodiment in that it has extended bent portions 433d, 433d that greatly protrude in both directions.

When the upper bent portion 432, the lower bent portion 433, and the side bent portions 434, 434 are bent substantially perpendicularly toward the first metal plate layer 41, the extended bent portions 432d and 433d are bent toward the end plate 4D. It protrudes greatly in the width direction (D2 direction) and is further bent substantially at a right angle toward the side bent portion 434 . As a result, the extended bent portions 432d and 433d overlap the surfaces of the side bent portions 434 and 434, respectively. The extended bent portions 432d and 433d correspond to the "third bent portion" of the present invention.

The overlapping portions of each extended bent portion 432d, 433d and the side bent portion 434, 434 are joined together. As a result, the extended bent portions 432d and 433d and the side bent portions 434 and 434 are integrally connected by a joint portion 438 formed in the overlapping portion. Joining can be performed, for example, by spot welding.

According to this end plate 4D, the upper bent portion 432, the lower bent portion 433, and the side bent portions 434, 434 are integrally connected by the extended bent portions 432d, 433d. The outer shape of the end plate 4D formed by the first metal plate layer 41 and the second metal plate layer 43 is box-shaped. Therefore, the rigidity of the end plate 4D can be further improved.

In the case of the end plate 4D according to the fifth embodiment as well, the upper bent portion and the lower bent portion may be provided in the first metal plate layer 41 similarly to the end plate 4B according to the third embodiment. In this case, an extension bent portion is provided on the first metal plate layer 41 side. Also, the first metal plate layer 41 is provided with either the upper bent portion 411 or the lower bent portion 412, and the second metal plate layer 43 is provided with either the lower bent portion 433 or the upper bent portion 432. good too. Further, the end plate 4D may be provided with only one of the upper bent portion 411 or 432 and the lower bent portion 412 or 433, although the moment of inertia of area is slightly inferior.

Furthermore, although not shown, a CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 of the end plate 4D, similarly to the end plate 4A according to the second embodiment.

<Sixth Embodiment of End Plate>
Next, a sixth embodiment of the end plate will be described with reference to FIGS. 19 and 20. FIG. FIG. 19 is an exploded perspective view showing a sixth embodiment of the end plate used in the battery module according to the invention. 20 is a cross-sectional view showing a main part of the end plate shown in FIG. 19. FIG. In FIG. 20, the second metal plate layer 43 is omitted. Parts having the same reference numerals as those of the end plate 4 of the first embodiment have the same configuration. The description of the first embodiment is used as long as there is no particular difference, and is omitted here.

Similar to the end plate 4 of the first embodiment, the end plate 4E has a three-layer structure in which a first metal plate layer 41/resin plate layer 42/second metal plate layer 43 are laminated in this order from the battery cell 2 side. However, it is different from the end plate 4 of the first embodiment in that the resin plate layer 42 has a strut frame member 46 .

The strut frame members 46 are made of the same metal as the nuts 44, and are arranged at both ends of the resin plate layer 42 in the width direction (D2 direction), specifically, on both end faces of the resin plate layer 42 in the width direction. there is The strut frame member 46 extends over the entire length in the height direction (D3 direction) of the resin plate layer 42 (end plate 4E). The support frame member 46 is sandwiched between the first metal plate layer 41 and the second metal plate layer 43 .

The strut frame member 46 and each nut 44 are integrated by a connecting portion 461 having the same thickness as the thickness of the strut frame member 46 and the nut 44 in the D1 direction. The connecting portion 461 individually connects between the strut frame member 46 and each nut 44 . By integrating the strut frame member 46 and the nut 44, both ends of the resin plate layer 42 in the width direction (D2 direction) are reinforced. Therefore, when the load due to the expansion of the battery cell 2 acts on both ends of the end plate 4E through the fastening member 5, the compression failure of the resin plate layer 42 is prevented or suppressed, and the creep resistance is greatly improved. The strut frame member 46 integrated with each nut 44 can be formed by extrusion, forging, casting, or the like.

Further, by integrating the support frame member 46 and the nut 44, the bonding area between the support frame member 46 and the resin plate layer 42 is increased, and the bonding strength is increased. For example, the strut frame member 46 may have a structure divided into three strut frame members that are integrated with the three nuts 44 one-to-one. However, by integrating one strut frame member 46 extending in the height direction (D3 direction) of the resin plate layer 42 with three nuts 44 as in this embodiment, the number of parts can be reduced. Moreover, since the strut frame member 46 and the plurality of nuts 44 form a single part, workability is also improved when arranging the plurality of nuts 44 between the first metal plate layer 41 and the second metal plate layer 42. .

The width of the connecting portion 461 in the height direction (D3 direction) may be equal to or greater than the outer diameter of the nut 44, but is preferably narrower than the outer diameter of the nut 44 as in the present embodiment. Since the space between the strut frame member 46 and each nut 44 is partially constricted at the connecting portion 461 , the resin of the resin plate layer 42 is trapped between the strut frame member 46 and each nut 44 . It can enter so as to sandwich the connection part 461 . 20, between the strut frame member 46 and each nut 44, the fitting portion 42a of the resin plate layer 42 is formed. D2 direction) is prevented, and the joint strength between the support frame member 46 and the nut 44 and the resin plate layer 42 can be further improved.

From the viewpoint of further improving the rigidity of the end plate 4E, the support frame member 46 is preferably in contact with the first metal plate layer 41 and the second metal plate layer 43. More preferably, it is joined to the metal plate layer 43 by welding or adhesion.

In the end plate 4E, when forming the resin plate layer 42, the resin forming the resin plate layer 42 is efficiently flowed between the support frame member 46 and each nut 44 at the time of insert molding. As with the end plate 4B of the third embodiment, it is desirable to inject the resin from the resin injection hole 436 provided in the central portion of the second metal plate layer 43 . At this time, it is desirable that the surface of the column frame member 46 that contacts the resin plate layer 42 is also subjected to the same roughening treatment or metal-resin bonding film treatment as described above.

Furthermore, although not shown, a CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 of the end plate 4E, similarly to the end plate 4A of the second embodiment.

<Seventh Embodiment of End Plate>
Next, an end plate according to a seventh embodiment will be described with reference to FIG. FIG. 21 is an exploded perspective view showing a seventh embodiment of the end plate used in the battery module according to the invention. Parts having the same reference numerals as those of the end plate 4E of the sixth embodiment indicate parts having the same configuration. Unless there is a particular difference, the description of the sixth embodiment is used, and the description thereof is omitted here.

In the end plate 4E of the sixth embodiment, the support frame members 46 are arranged only at both ends in the width direction (D2 direction) of the peripheral end portions of the resin plate layer 42, but the end plate 4F is made of resin. It differs from the end plate 4</b>E of the sixth embodiment in that a support frame member 47 is arranged at the end portion of the entire circumference of the plate layer 42 .

The strut frame member 47 has the same pair of strut frame members 46, 46 (vertical strut frame members) as the end plate 4E of the sixth embodiment, and both ends in the height direction (D3 direction) of the resin plate layer 42, Specifically, a pair of support frame members 471 (horizontal support frame members) are provided on both end surfaces of the resin plate layer 42 in the height direction. Each strut frame member 471 connects and integrates a pair of strut frame members 46 , 46 . As a result, the end plate 4F is reinforced by the metal strut frame member 47 extending over the entire circumference of the resin plate layer 42, so that in addition to the effects of the end plate 4E of the sixth embodiment, ) has the effect of further improving the rigidity.

From the viewpoint of further improving the rigidity of the end plate 4F, the support frame member 47 is preferably in contact with the first metal plate layer 41 and the second metal plate layer 43. More preferably, it is joined to the two metal plate layers 43 by welding or adhesion.

Although not shown, the CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 in this end plate 4F as well as the end plate 4A of the second embodiment.

<Eighth Embodiment of End Plate>
Next, an end plate according to an eighth embodiment will be described with reference to FIGS. 22 and 23. FIG. FIG. 22 is an overall perspective view showing an eighth embodiment of the end plate used in the battery module according to the invention. 23 is a plan view of the end plate shown in FIG. 22. FIG. Parts having the same reference numerals as those of the end plate 4 of the first embodiment have the same configuration. The description of the first embodiment is used as long as there is no particular difference, and is omitted here.

Similar to the end plate 4 of the first embodiment, the end plate 4G has a three-layer structure in which a first metal plate layer 41/resin plate layer 42/second metal plate layer 43 are laminated in this order from the battery cell 2 side. However, it is different from the end plate 4 of the first embodiment in that the resin plate layer 42 has a plurality of lightening portions 422 .

The lightening portion 422 is a hollow portion in which the resin of the resin plate layer 42 does not exist. The lightening portions 422 of the present embodiment extend in the height direction (D3 direction) of the resin plate layer 42 and are arranged parallel to each other at regular intervals in the width direction (D2 direction) of the resin plate layer 42. It is Each lightening portion 422 is open to both ends in the height direction (D3 direction) of the resin plate layer 42 and to the first metal plate layer 41 side, but is not open to the second metal plate layer 43 side. . Therefore, a thin resin plate portion 42b remains between each lightening portion 422 and the second metal plate layer 43, as shown in FIG.

Thus, by providing the resin plate layer 42 with the lightening portion 422, the weight of the end plate 4G can be reduced. Even if the weight of the end plate 4G is reduced, the rigidity of the end plate 4G is not lowered. This is explained below.

First, as shown in FIG. 24A, the moment of inertia of area per cross-sectional area of a solid structure without lightening portions is considered. Assuming that the width of the solid structure is b and the height is h1, the geometrical moment of inertia I and the cross-sectional area S of the solid structure are as follows.
I=b×h1 ³ /12
S = b x h1
Therefore, the geometric moment of inertia I/S per cross-sectional area of the solid structure is as follows.
I/S=h1 ² /12

On the other hand, as shown in FIG. 24B, the cross-sectional quadratic per cross-sectional area of the hollow structure, which is similarly a structure of width b×height h1, but whose central portion is hollowed out by a lightening portion of height h2 Think moment. The geometric moment of inertia I and the cross-sectional area S of this hollow structure are as follows.
I=b×(h1 ³ −h2 ³ )/12
S=b×(h1−h2)
Therefore, the geometric moment of inertia I/S per cross-sectional area of the hollow structure is as follows.
I/S=(h1 ² +h1h2+h2 ² )/12
Therefore, the second moment of area per cross-sectional area is larger in the hollow structure than in the solid structure. In other words, the hollow structure has a higher stiffness per weight.

Next, as shown in FIGS. 25A and 25B, the amount of three-point bending deflection of the hollow structure X having the resin portion x2 of thickness t between the metal portions x1 and x1 will be considered. The bending direction of the hollow structure X is assumed to be along the direction of the length L as indicated by an arrow. In FIGS. 25A and 25B, three resin portions x2 are arranged in parallel with an interval t between metal portions x1 and x1. The width of the hollow structure X is 6t. In the hollow structural body X, the portion corresponding to the resin plate portion 42b shown in FIG. 23 is omitted for simplification of trial calculation.
This three-point bending deflection amount WL ³ /48EI is as follows.
WL ³ /{(4×6×(6 ³ −4 ³ )×t ⁴ ×Em)+(4×3×4 ³ ×t ⁴ ×Ep)}
W: load, Em: modulus of elasticity of metal part, Ep: modulus of elasticity of resin part The unit weight of this hollow structure X is as follows.
12t2×L×ρm+12t2×L×ρp
ρm: Density of metal part, ρp: Density of resin part

On the other hand, similarly, as shown in FIG. 25C, the amount of three-point bending deflection of the solid structure Y in which the space between the metal portions y1 and y1 is filled with the resin portion y2 is considered. The solid structure Y has the same width 6t and length L as the hollow structure X.
This three-point bending deflection amount WL ³ /48EI is as follows.
WL ³ /{(4×6×(6 ³ −4 ³ )×t ⁴ ×Em)+(4×6×4 ³ ×t ⁴ ×Ep)}
Moreover, the unit weight of this solid structure Y is as follows.
12t2×L×ρm+24t2×L×ρp

In each of the above formulas, W: 1000 N, L: 100 mm, Em: 200 GPa, Ep: 2.2 GPa, ρm: 7860 kg/m ³ , ρp: 1200 kg/m ³ , and the amount of deflection and weight when t is varied was calculated, and the relationship between the amount of deflection and the weight of the hollow structure X and the solid structure Y was obtained. The results are shown in FIG.
As shown in FIG. 26, when the amount of deflection is the same (the rigidity is the same), the weight of the hollow structure X is lighter than that of the solid structure Y. As shown in FIG. Therefore, the end plate 4G having a plurality of lightening portions 422 as shown in FIGS. 22 and 23 does not lower its rigidity even when the lightening portions 422 reduce the weight.

Although not shown, the CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 in this end plate 4G as in the end plate 4A of the second embodiment.

<Ninth Embodiment of End Plate>
Next, a ninth embodiment of the end plate will be described with reference to FIGS. 27 and 28. FIG. FIG. 27 is an overall perspective view showing a ninth embodiment of the end plate used in the battery module according to the present invention. 28 is a plan view of the end plate shown in FIG. 27; FIG. Parts having the same reference numerals as those of the end plate 4G of the eighth embodiment indicate parts having the same configuration. The description of the eighth embodiment is used unless there is a particular difference, and is omitted here.

Similar to the end plate 4G of the eighth embodiment, the end plate 4H has a resin plate layer 42 in which a plurality of lightening portions 422 extending in the height direction are arranged parallel to the width direction. The surface in contact with the second metal plate layer 43 in the end of the eighth embodiment is convexly curved toward the second metal plate layer 43 along the width direction (D2 direction) of the resin plate layer 42 . It differs from plate 4G. The surface of the resin plate layer 42 in contact with the first metal plate layer 41 remains flat. The second metal plate layer 43 is provided along the curved shape of the resin plate layer 42 . Therefore, the distance between the first metal plate layer 41 and the second metal plate layer 43 is the largest at the central portion in the width direction.

The depth of the lightening portion 422 from the first metal plate layer 41 toward the second metal plate layer 43 corresponds to the thickness of the resin plate layer 42 (the gap between the first metal plate layer 41 and the second metal plate layer 43). is doing. That is, the depth of the lightening portions 422 arranged in the widthwise central portion of the resin plate layer 42 is greater than the depth of the lightening portions 422 arranged at both end portions in the widthwise direction of the resin plate layer 42 . . That is, the depth of the lightening portion 422 gradually increases from the lightening portions 422 at both ends in the width direction of the resin plate layer 42 to the lightening portion 422 at the central portion.

According to this end plate 4H, in addition to the same effect as the end plate 4G of the eighth embodiment, there is an effect of further suppressing bending. That is, since the end plates are fixed by the fastening members at both ends, the distribution of the bending moment when the load (white arrow) due to the expansion of the battery cell acts as shown in FIG. , the central portion in the width direction is curved most outwardly according to the load. At this time, when the end plate 4G of the eighth embodiment has a flat plate shape and has the hollowed portions 422 of the same shape, the elastic modulus is lower than that of metal at both ends to which the fastening member is fixed. The deformation of the resin portion in the lateral direction tends to increase the deflection as a whole. However, since the end plate 4H of the present embodiment has a shape in which the central portion in the width direction is curved most outward in response to this bending moment distribution, the rigidity corresponding to the bending moment distribution is high. Compared to the end plate 4G of the eighth embodiment, which is adjusted and formed into a flat plate shape, deflection can be suppressed.

Although not shown, in this end plate 4H, a CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 as in the case of the end plate 4A of the second embodiment.

<Tenth Embodiment of End Plate>
Next, a tenth embodiment of the end plate will be described with reference to FIGS. 30 to 32. FIG. FIG. 30 is an overall perspective view showing a tenth embodiment of the end plate used in the battery module according to the present invention; 31 is an exploded perspective view of the end plate shown in FIG. 30 as seen from the back side. FIG. 32 is a cross-sectional view taken along line CC in FIG. 30. FIG. Parts having the same reference numerals as those of the end plate 4H of the ninth embodiment indicate parts having the same configuration. The description of the ninth embodiment is used as long as there is no particular difference, and is omitted here.

As with the end plate 4H of the ninth embodiment, this end plate 4I has a plurality of lightening portions 422 arranged in the resin plate layer 42, but the extending direction of the lightening portions 422 is the same as that of the ninth embodiment. end plate 4H. That is, the lightening portion 422 of the end plate 4I extends in the width direction (D2 direction) of the end plate 4I and is arranged parallel to the height direction (Z direction).

The depth of the lightening portion 422 from the first metal plate layer 41 toward the second metal plate layer 43 corresponds to the change in thickness of the resin plate layer 42 in the width direction (the curved shape of the second metal plate layer 43). there is That is, the depth of the lightening portion 422 gradually increases from both ends of the resin plate layer 42 in the width direction toward the central portion of the resin plate layer 42 in the width direction.

According to this end plate 4I, in addition to the same effects as those of the end plates 4G and 4H of the eighth and ninth embodiments, when the resin plate layers 42 of the end plate 4I are viewed in the width direction, they are adjacent to each other in the height direction. Since the space between the matching lightening portions 422, 422 has a solid structure corresponding to the distribution of the bending moment shown in FIG. However, deflection can be further suppressed as compared with the end plates 4G and 4H of the eighth and ninth embodiments.

Although not shown, in this end plate 4H, a CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43 as in the case of the end plate 4A of the second embodiment.

<Eleventh Embodiment of End Plate>
Next, an eleventh embodiment of the end plate will be described with reference to FIG. FIG. 33 is a front view showing a resin plate layer of an eleventh embodiment of an end plate used in a battery module according to the present invention; Parts having the same reference numerals as those of the end plate 4G of the eighth embodiment indicate parts having the same configuration. The description of the eighth embodiment is used unless there is a particular difference, and is omitted here.

The resin plate layer 42 of the end plate 4J has a plurality of cutouts 423 in common with the endplate 4G of the eighth embodiment, but the cutouts 423 of the eighth embodiment have a honeycomb shape. end plate 4G. The honeycomb-shaped lightening portions 423 of the present embodiment are arranged in a matrix in the width direction (D2 direction) and the height direction (D3 direction) of the resin plate layer 42 . Further, each lightening portion 423 is provided so as to penetrate the resin plate layer 42 from the first metal plate layer 41 (not shown) to the second metal plate layer 43 (not shown). By forming the cutout portion 423 into a honeycomb shape, the rigidity of the resin plate layer 42 can be increased while reducing the weight of the end plate 4J.

Also in this end plate 4J, a CFRP plate layer 45 may be laminated on the outer surface of the second metal plate layer 43, as in the end plate 4A of the second embodiment.

<Another Embodiment of End Plate Manufacturing Method>
Next, another embodiment of the method for manufacturing the end plate used in the battery module according to the present invention will be described with reference to FIGS. 34A, 34B and 35. FIG.
34A and 34B are diagrams explaining another embodiment of the method of manufacturing the end plate used in the battery module according to the present invention. 35A and 35B are diagrams illustrating a method of manufacturing the end plate shown in FIGS. 27 and 28. FIG.

In the manufacturing method of this embodiment, first, as shown in FIG. 34A, a resin plate is formed on the surface of one of the two metal plate layers 41 and 43 (the second metal plate layer 43 in this embodiment). Layer 42 is formed, for example, by molding. The resin used to form the resin plate layer 42 contacts and adheres to the surface of the second metal plate layer 43 in a molten state, and is then joined to the second metal plate layer 43 by cooling and hardening. . As a result, between the resin plate layer 42 and the second metal plate layer 43, the resin of the resin plate layer 42 is closely attached to the second metal plate layer 43 to form a joint portion 48 that is integrally joined. At this time, although not shown, a nut 44 is arranged in advance on the surface of the second metal plate layer 43 and embedded in the resin plate layer 42 . Moreover, it is preferable that the surface of the second metal plate layer 43 is previously subjected to the roughening treatment or the metal-resin bonding film treatment described above.

Next, after flattening the surface of the resin plate layer 42 as necessary, the first metal plate layer 41 is placed. It is preferable that the first metal plate layer 41 also be previously subjected to the roughening treatment or the metal-resin bonding film treatment described above. Thereafter, as shown in FIG. 34B, the first metal plate layer 41 is pressed against the resin plate layer 42, and further heated to a temperature at which the resin plate layer 42 can be melted again. The remelted resin of the resin plate layer 42 contacts and adheres to the surface of the first metal plate layer 41 in a melted state, and is then joined to the first metal plate layer 41 by cooling and hardening the resin. As a result, between the resin plate layer 42 and the first metal plate layer 41 also, there is a joint portion 49 where the resin of the resin plate layer 42 is in close contact with the first metal plate layer 41 and integrated.

According to this manufacturing method, the mold for forming the resin plate layer 42 can be simplified, so the cost of the end plate can be reduced. Since there is no need to insert a resin, there is no limitation on the resin thickness due to the fluidity of the resin, and a decrease in the strength of the resin plate layer 42 due to welding can be avoided. Moreover, since this manufacturing method also improves the degree of freedom in the shape of the resin plate layer 42, it is applicable not only to the case of forming the resin plate layer 42 in the end plates 4 to 4F described above, but also to the end plates 4G to 4J. It can also be applied to the case of forming a complicated-shaped resin plate layer 42 having a plurality of lightening portions 422 and 423, as shown in FIG. For example, as shown in FIG. 35, when manufacturing the end plate 4H, a resin plate layer 42 having hollowed portions 422 is formed in advance on the second metal plate layer 43, and then the first metal plate layer 41 is applied. Bonding by pressure and heat eliminates the need for a slide mold for forming the lightening portion 422 required in insert molding.

The resin plate layer 42 may be formed on the surface of the first metal plate layer 41 and then the second metal plate layer 43 may be joined to the surface of the resin plate layer 42 .

EXAMPLES The effects of the present invention are illustrated by examples below.
(Example 1)
As shown in FIG. 36, a laminate having a three-layer structure of first metal plate layer LA1/resin plate layer LA2/second metal plate layer LA3 was prepared. The laminate has a height H=50 mm, a width W=100 mm, and a depth D=14 mm. The first metal plate layer LA1 is a steel plate with a thickness of 2 mm, the resin plate layer LA2 is a polyphenylene sulfide with a thickness of 10 mm, and the second metal plate layer LA3 is a steel plate with a thickness of 2 mm. The resin plate layer LA2 is integrally insert-molded by injecting a resin material between the first metal plate layer LA1 and the second metal plate layer LA3. The inner surfaces of the first metal plate layer LA1 and the second metal plate layer LA3 are roughened in advance by being immersed in a chemical etching solution, and the layers are firmly bonded.

Both ends of the laminate on the side of the second metal plate layer LA3 in the width direction are supported and fixed along the height direction so as to be in the same state as the fastening and fixing by the fastening member 5 described above, and the laminate is A pressing force of 1 MPa was applied as indicated by an arrow from the widthwise central portion of the first metal plate layer LA1 side. FIG. 37 shows how the laminate is deformed at that time. Although the laminate is deformed such that the central portion in the width direction swells slightly from the side of the first metal plate layer LA1 toward the side of the second metal plate layer LA3, the amount of deformation is extremely small. Almost no residual strain was found in the resin plate layer LA2, and the laminate had high strength and rigidity.

(Comparative example 1)
As shown in FIG. 38, a laminate having a two-layer structure of resin plate layer LA11/metal plate layer LA12 was prepared. The laminate has a height H=50 mm, a width W=100 mm, and a depth D=14 mm. The resin plate layer L11 is polyphenylene sulfide with a thickness of 12 mm, and the metal plate layer LA12 is a steel plate with a thickness of 2 mm. The resin plate layer LA11 is integrally insert-molded on one side of the metal plate layer LA12. The metal plate layer LA12 is roughened by being immersed in the same chemical etching solution as in Example 1, and is firmly bonded to the resin plate layer LA11.

Exactly the same as in Example 1, a pressing force of 1 MPa was applied to this laminate as indicated by the arrow. FIG. 39 shows how the laminate is deformed at that time. The laminate was deformed such that the central portion in the width direction swelled from the resin plate layer LA11 side toward the metal plate layer LA12 side more than the laminate shown in the example. The distortion caused by the application of the pressing force remained in both end portions and the central portion of the resin plate layer LA11.

(Comparative example 2)
Similar to FIG. 36, a laminate having a three-layer structure of first metal plate layer LA21/resin plate layer LA22/second metal plate layer LA23 was prepared. However, the first metal plate layer LA21, the second metal plate layer LA23, and the resin plate layer LA22 are not firmly bonded, but have a sliding bond (coefficient of friction: 0.1).

A pressing force of 1 MPa was applied to this laminate in exactly the same manner as in the example. FIG. 40 shows how the laminate is deformed at that time. The laminate was deformed such that a large gap occurred between the layers and the center portion in the width direction swelled greatly. In the resin plate layer LA22, a strong strain remained in the central portion when the pressing force was applied.

1 battery module 2 battery cell 4, 4A to 4I end plate 41 first metal plate layer 41a surface (of first metal plate layer) 42 resin plate layer 422, 423 hollow portion 43 second metal plate layer 43b second metal plate outer surface of layer 432 upper fold (first fold)
432a tip (of upper fold) 432c edge (of upper fold) 433c edge (of lower fold) 432d, 433d extension fold (third fold)
433 Lower Bend (Second Bend)
433a tip (of lower fold) 434 side fold (second fold)
434a tip (of side bend) 434c edge (of side bend) 44 nut (metal hollow column member)
44a End face of nut (one end face of metal hollow column member)
44b End face of nut (other end face of metal hollow column member)
45 CFRP plate layer 46, 460 strut frame member 461 connecting portion 5 fastening member 52 bolt (fixing member)
7 insulating plate

Claims (21)

A battery module in which end plates are arranged at both ends of a plurality of stacked battery cells in the stacking direction, and the end plates are fastened together with a fastening member, so that the entire battery cells are sandwiched between the end plates. and
The end plate has a three-layer structure in which a first metal plate layer/resin plate layer/second metal plate layer is laminated in this order from the battery cell side, or a first metal plate layer/resin plate layer/second metal plate. It has a four-layer structure laminated in the order of plate layer / carbon fiber reinforced plastic plate layer,
In the first metal plate layer, the resin plate layer, and the second metal plate layer, the molten resin forming the resin plate layer adheres to the first metal plate layer and the second metal plate layer and hardens. The battery module is an integrally molded product that is joined and integrated by pressing, wherein the thickness of the resin plate layer is greater than the thickness of each of the first metal plate layer and the second metal plate layer. 2. The battery module according to claim 1 , wherein said resin plate layer has a plurality of lightening portions. 3. The battery module according to claim 2 , wherein said lightening portion extends in the height direction of said resin plate layer and is arranged parallel to the width direction of said resin plate layer. 3. The battery module according to claim 2 , wherein said lightening portion extends in the width direction of said resin plate layer and is arranged parallel to the height direction of said resin plate layer. The surface of the resin plate layer in contact with the second metal plate layer is convexly curved so that the distance between the first metal plate layer and the second metal plate layer is greatest at the central portion in the width direction. and
5. The depth of the lightening portion from the first metal plate layer toward the second metal plate layer according to claim 3 or 4 , wherein the central portion is deeper than both ends in the width direction of the resin plate layer. battery module. 3. The battery module according to claim 2 , wherein said lightening portion has a honeycomb shape. The fastening member according to any one of claims 1 to 6 , wherein the fastening member is fixed to the surface of the second metal plate layer or the carbon fiber reinforced plastic plate layer arranged on the outermost surface of the end plate. battery module. 8. The battery module according to claim 7 , wherein said second metal plate layer or said carbon fiber reinforced plastic plate layer to which said fastening member is fixed constitutes a layer having the highest rigidity in said end plate. The resin plate layer has a plurality of metal hollow column members through which the fixing member of the fastening member is inserted, and one end surface of the metal hollow column member is in contact with the first metal plate layer. 9. The battery module according to claim 7 , wherein the other end face is in contact with said second metal plate layer. 10. The battery according to claim 9 , wherein one end face of said hollow metal pillar member is fixed to said first metal plate layer, and the other end face of said hollow metal pillar member is fixed to or in contact with said second metal plate layer. module. A metal support frame member sandwiched between the first metal plate layer and the second metal plate layer is arranged at least at both ends in the width direction of the peripheral ends of the resin plate layer,
11. The battery module according to claim 9 , wherein said support frame member is integrated with said hollow metal column member. A connecting portion for integrating the support frame member and the hollow metal column member is formed to have a width narrower than the outer diameter of the hollow metal column member, and the resin of the resin plate layer sandwiches the connecting portion. 12. The battery module according to claim 11 , which is inserted between said strut frame member and said hollow metal column member. 13. The battery module according to claim 11 , wherein said strut frame member is arranged at the end of the entire periphery of said resin plate layer. The battery module according to any one of claims 11 to 13 , wherein said support frame portion is in contact with or joined to said first metal plate layer and said second metal plate layer. At least one of the first metal plate layer and the second metal plate layer is bent toward the second metal plate layer or the first metal plate layer at least one end in the height direction. 15. The battery module according to any one of claims 1 to 14 , having a curved first fold. The fastening members are fixed to both ends of the end plate in the width direction,
16. The second metal plate layer has second bent portions at both ends in the width direction thereof, the corner portions being bent toward the first metal plate layer so that the corners are rounded. The battery module according to any one of . The fastening members are fixed to both ends of the end plate in the width direction,
At least one of the first metal plate layer and the second metal plate layer is bent toward the second metal plate layer or the first metal plate layer at least one end in the height direction. having a first bent portion with a
The second metal plate layer has, at both ends in the width direction thereof, second bent portions that are bent toward the first metal plate layer so that the corners thereof have an R shape,
The battery module according to any one of claims 1 to 14, wherein both edges in the width direction of said first bent portion and edges in the height direction of said second bent portion are joined to each other. . The fastening members are fixed to both ends of the end plate in the width direction,
At least one of the first metal plate layer and the second metal plate layer is bent toward the second metal plate layer or the first metal plate layer at least one end in the height direction. having a first bent portion with a
The second metal plate layer has, at both ends in the width direction thereof, second bent portions that are bent toward the first metal plate layer so that the corners thereof have an R shape,
At both ends in the width direction of the first bent portion, the third bent portion is bent so as to overlap the surface of the second bent portion,
The battery module according to any one of claims 1 to 14 , wherein overlapping portions of said second bent portion and said third bent portion are joined together. 19. The battery module according to claim 15, 17 or 18 , wherein the tip of said first bent portion is in contact with the inner surface of said second metal plate layer or said first metal plate layer. 19. The battery module according to claim 16, 17 or 18 , wherein the tip of said second bent portion is in contact with the inner surface of said first metal plate layer. The battery module according to any one of claims 1 to 20 , further comprising an insulating plate arranged between the outermost battery cell and the first metal plate layer of the end plate.

Images