Battery module

Abstract

Provided is a storage battery module configured so that a module stowed inside including a battery cell is not deformed or damaged by vibration of a fixed part during operation.　A storage battery module according to an embodiment comprises a plurality of battery cells, and a box-form case in which the battery cells are stored, the storage battery module being characterized in that: the case has a fixed surface, an upper surface facing the fixed surface, and a cover surface, a first side surface, a second side surface, and a third side surface that connect between the fixed surface and the upper surface; and a lattice truss rib composed of a lattice-form rib and a rhombus-shaped rib formed inside the lattice-form rib is regularly formed on the first side surface, the second side surface, the third side surface, and the outer wall of the upper surface.

Description

Technical Field

[0001] Embodiments of the present invention relate to a battery module incorporating battery cells mounted in an electric vehicle or the like.

Background Art

[0002] For example, a storage battery (also referred to as a secondary battery device) used in an electric vehicle such as a hybrid vehicle or an electric vehicle needs to handle high power and frequent output changes. Such a storage battery is used by electrically connecting a plurality of built-in battery cells in series or in parallel according to the required output and capacity. It is also configured as a mechanically integrated battery module.

[0003] In a battery module, for example, a plurality of battery cells are housed side by side vertically or horizontally in a case. A monitoring board for detecting the voltage etc. of the plurality of battery cells is also provided on the case. And a cover is attached so as to cover these plurality of battery cells and the monitoring board. Such a battery module used in an electric vehicle needs to take measures against vibrations (for example, vertical and longitudinal vibrations) received during driving.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide a battery module in which components and a case housed inside including battery cells are not deformed or damaged due to vibrations received by a fixed part during operation.

Means for Solving the Problems

[0006] The battery module of the embodiment comprises a plurality of battery cells and a box-shaped case in which the battery cells are housed, wherein the case has a fixed surface, an upper surface facing the fixed surface, a cover surface connecting the fixed surface and the upper surface, a first side surface, a second side surface, and a third side surface, and is characterized in that lattice truss ribs, consisting of lattice-shaped ribs and rhombic ribs formed inside the lattice-shaped ribs, are regularly formed on the outer walls of the first side surface, the second side surface, the third side surface and the upper surface. [Effects of the Invention]

[0007] In the battery module of this embodiment, a lattice truss rib structure is formed on the outer walls of the first side, second side, third side, and top surface, which can mitigate the effects of vibrations on the battery module. Furthermore, since the lattice truss ribs have the same shape and are designed to become smaller as they approach fastening points where stress concentration is high, the load can be reduced. In addition, since the truss ribs of the fixed part are designed perpendicular to the sliding surface of the fixed position, the strength in the direction perpendicular to the fixed part can be increased, and resistance to bending can be achieved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of the battery module according to the embodiment, with the fixed surface facing downwards. [Figure 2] This is a perspective view of the battery module according to the embodiment, with the fixed surface facing upwards. [Figure 3] This figure shows the shape of the outer wall (first embodiment) of the first side (longitudinal direction) of the battery module according to the embodiment. [Figure 4] This figure shows the shape of the outer wall (second embodiment) of the first side (longitudinal direction) of the battery module according to the embodiment. [Figure 5] (a) is a diagram showing the shape of the fixing part of the battery module according to the embodiment, and (b) is a cross-sectional view AA of (a). [Figure 6](a) is a cross-sectional view of the case surface BB on the first side (longitudinal direction) of the battery module according to the embodiment, and (b) is a cross-sectional view CC of a battery module without rhombus ribs and truss ribs, as a comparative example. [Figure 7] This is an exploded perspective view illustrating an example configuration of a battery module according to an embodiment. [Figure 8] These diagrams illustrate deformation due to vibration in a battery module. (a) shows an example of change as viewed from the front (longitudinal direction), and (b) shows an example of change as viewed from the side (short direction). [Modes for carrying out the invention]

[0009] The battery module according to this embodiment will be described below with reference to the drawings. Figures 1 and 2 are perspective views showing the overall configuration of the battery module 10 according to the embodiment. Figure 1 shows a perspective view with the fixed surface 20 facing downwards. Figure 2 shows a perspective view with the fixed surface 20 facing upwards. In the figures, XYZ indicate directions as viewed from the fixed surface 20. For example, X indicates the longitudinal direction of the side, Y indicates the short direction of the side, and Z indicates the vertical direction.

[0010] As shown in Figures 1 and 2, the battery module 10 has a box-like (rectangular) shape. The battery module 10 consists of a first case indicated by arrow 10a and a second case indicated by arrow 10b, which are joined together and secured at multiple points on the joint by screws (not shown). Hereinafter, the first and second cases together will be referred to as the case. Battery cells (not shown) are housed inside the case. The case is made of, for example, polypropylene and has insulating properties. It may also be made of other synthetic resins or other materials such as metal coated with insulating material.

[0011] The case has six sides. These six sides are the fixed side 20, the cover side 30, the top side 40, the first side 50, the second side 60, and the third side 70. The fixed surface 20 is the surface on which the battery module 10 is attached to the mounting part of an electric vehicle or the like. The top surface 40 is the surface facing the fixed surface 20. The cover surface 30, the first side surface 50, the second side surface 60, and the third side surface 70 connect the fixed surface 20 and the top surface 40. The cover surface 30 is provided with terminals for connecting power cables and connectors for communication cables (not shown). The power cables and communication cables may also be directly connected to the fixed surface 20.

[0012] The first side surface 50 is the surface facing the cover surface 30, and a first fixing portion 50a is provided at its end on the side facing the fixed surface 20. The second side surface 60 and the third side surface 70 are the sides located between the first side surface 50 and the cover surface 30. The second side surface 60 and the third side surface 70 face each other. A second fixing portion 60a is provided at the end of the second side surface 60 on the side facing the fixed surface 20. A third fixing portion 70a is also provided at the end of the third side surface 70 on the side facing the fixed surface 20.

[0013] The first fixing part 50a, the second fixing part 60a, and the third fixing part 70a are provided extending from their respective sides to the fixing surface 20, and are inserted into bolts (not shown) to fix the battery module 10 to the mounting part. Here, the structure is designed to fix at each of the three sides (i.e., three locations), but it may also be designed to fix at all sides (four locations).

[0014] Inside the battery module 10, as shown in Figure 7 later, multi-layered (for example, 4 or 5 layers) battery cells 200 are housed stacked in the Z direction. When the electronic cells 200 are multi-layered, it has been confirmed that vibrations experienced by the electric vehicle on which it is installed place a load on the first fixing part 50a, the second fixing part 60a, and the third fixing part 70a.

[0015] Figure 8 illustrates deformation due to vibration in a battery module. Figure 8(a) shows an example of side deformation viewed from the front (longitudinal direction), and Figure 8(b) shows an example of side deformation viewed from the side (short direction). As shown in FIG. 8, for example, in a battery module having a fixing structure at three locations, it was observed that forces were applied toward each fixing portion and ribs or the like formed on the outer wall thereof were bent. Further, when the strength and rigidity of the fixing portion were low, deformation of the ribs was observed. Furthermore, when driving on a rough road (bad road) with irregularities, a strong load will continue to be applied, which may lead to damage to each fixing portion. Such deformation of the battery module may cause damage to the built-in devices and members during operation.

[0016] Therefore, as shown in FIG. 1, in the battery module 10 of the embodiment, lattice-truss ribs 100 are formed on at least the outer walls (excluding the cover surface 30) of the upper surface 40, the first side surface 50, the second side surface 60, and the third side surface 70, so as to enhance the strength of the outer wall of the battery module 10. Furthermore, as shown in FIG. 2, lattice-truss ribs 100 are also formed on the fixing surface 20. Thereby, the strength of the outer wall of the fixing surface 20 is also enhanced. As a result, a robust fixing surface 20 can be formed.

[0017] FIGS. 3 and 4 are diagrams showing the shape of the lattice-truss ribs 100 regularly formed on the first side surface 50 facing the cover surface 30. As shown in FIGS. 3 and 4, the lattice-truss ribs 100 have a shape in which diamond-shaped ribs 120 are provided inside lattice-shaped ribs 110. The lattice-truss ribs 100 are formed on the first side surface 50, the second side surface 60, and the third side surface, and the upper surface 40, excluding the cover surface 30, mainly to reduce impact.

[0018] By forming the lattice-truss ribs 100 in the same shape and with regularity on each wall surface of at least the upper surface 40, the first side surface 50, the second side surface 60, and the third side surface 70, the structure of the battery module 10 exhibits the effect of reducing vibration-induced load and deformation.

[0019] In Figure 3, each lattice truss rib 100 is approximately the same size and is regularly arranged on the outer wall of the first side surface 50. By reinforcing the inside of the lattice rib 110 with a rhombic rib 120, the strength can be increased and the rigidity can be improved compared to a structure with only the lattice rib 110. As a result, even if the battery module 10 mounted on an electric vehicle is subjected to vibration, deformation as shown in Figure 8 can be prevented. In other words, the shape is resistant to bending when subjected to a load directed toward the first fixed part 50a (a load from the left and right X directions outward in Figure 3). Furthermore, the fixing portions 60a, 70a on the second side 60 and the third side 70, which are not shown in the diagram, are also shaped to resist bending under loads directed towards each fixing portion 60a, 70a (loads from the outside in the front-to-back Y direction). Therefore, there is no risk of deformation or damage to the built-in battery cells.

[0020] In Figure 4, each lattice truss rib 100 is designed to fold or compress toward the central part where the first fixing part 50a is located. That is, the lattice rib 110 has a shape that narrows in width toward the central part (on the Z axis of the first fixing part 50a). Therefore, the rhombus rib 120 formed inside the lattice rib 110 has a shape that becomes smaller toward the central part where the first fixing part 50a is located.

[0021] By forming the lattice truss rib 100 as shown in Figure 4, the strength can be further increased, and the rigidity can be made even higher. As a result, even if the battery module 10 mounted on an electric vehicle is subjected to vibration, for example, deformation as shown in Figure 8 can be prevented. In other words, the shape is more resistant to bending when subjected to a load directed toward the central part where the first fixing part 50a is located. Therefore, there is no risk of deformation or damage to the built-in battery cells.

[0022] Figure 5(a) is an enlarged view of frame 20a in Figure 2, showing the truss shape formed in the first fixing part 50a. Figure 5(b) shows a cross-sectional view AA of Figure 5(a). Here, the first fixing part 50a is shown as an example, but the second fixing part 60a and the third fixing part 70a may also adopt the same shape.

[0023] As shown in Figures 5(a) and (b), the structure is such that a truss rib 150 extending in the depth direction (Z direction) is formed on the outer circumference (X direction) of the first fixing part 50a. Furthermore, the truss rib 150 has a shape based on a triangle as its basic unit and is formed to become smaller in the X direction toward the first fixing part 50a. This suppresses the bending of the rib in the first fixing part 50a where stress concentration is high, and reduces the load. In other words, by adding a truss rib 150 in the Z direction perpendicular to the X direction where stress is applied, deformation can be suppressed. As a result, the first fixing part 50a where stress concentration occurs is reinforced more rigidly, making it less prone to bending.

[0024] Figure 6(a) shows a cross-sectional view of the BB of the truss rib 150 of the first fixed part 50a. Figure 6(b) shows a cross-sectional view of the CC at the same position in a battery module without a diamond-shaped rib 120 and the truss rib 150, as a comparative example. As shown in Figure 6(a), the battery cover 10 has two legs formed by the truss ribs 150, which increases the cross-sectional area and thus increases its strength against vibration.

[0025] In contrast, as shown in the simplified CC diagram in Figure 6(b), in a battery module without truss ribs 150, the cross-section is only the area of ​​the grid-like ribs 110, so it can be seen that the cross-sectional area is smaller than that in Figure 6(a). Therefore, it cannot be said that it has sufficient strength against vibration.

[0026] In this way, by adding truss ribs 150 in the Z direction to the first fixed section 50a, the cross-sectional area can be increased. This increases the second moment of area in the deformation direction. As a result, it becomes more resistant to bending and rigidity can be increased. In this way, by combining lattice ribs and truss ribs, impact can be mitigated and deformation and bending of the module can be prevented.

[0027] Figure 7 shows a part of the internal structure of a storage battery. Here, a first case 10aa, a second case 10bb, and a 5-layer x 2-row battery cell 200 are shown. Note that in Figure 7, the grid truss ribs formed on the outer walls of the first case 10aa and the second case 10bb are omitted from the illustration. A 4 x 2-row spacer 210 is integrally formed inside the second case 10bb. Each battery cell 200 is insulated by the spacer 210 and arranged accordingly. The top surface of each battery cell 200 is covered by the first case 10aa, and the first case 10aa and the second case 10bb are fixed together with screws. A busbar, a wiring board, a top cover which will become the cover surface 30, etc., are further attached to the first case 10aa. These structures may be well-known, such as those described in Japanese Patent Publication No. 6168986, so their explanation is omitted.

[0028] As described above, the battery module 10 of this embodiment has a structure in which lattice truss ribs 100 are formed on the outer walls of the first side surface 50, the second side surface 60, the third side surface 70, and the top surface 40, thereby mitigating the effects of vibration on the battery module 10. Furthermore, the lattice truss ribs 100 are designed to be the same shape and become smaller as they approach fastening points where stress concentration is high, thus reducing the load. In addition, the truss ribs 150 of the fixed part are designed to be perpendicular to the sliding surface of the fixed position, thereby increasing the strength in the direction perpendicular to the fixed part and providing resistance to bending.

[0029] The battery module of this embodiment is a battery module 10 comprising a plurality of battery cells 200 and a box-shaped case in which the battery cells 200 are housed. The case has a fixed surface 20, an upper surface 40 facing the fixed surface 20, a cover surface 30 connecting the fixed surface 20 and the upper surface 40, a first side surface 50, a second side surface 60, and a third side surface 70. A grid truss rib 100, consisting of grid-shaped ribs 110 and rhombic ribs 120 formed inside the grid-shaped ribs 110, is regularly formed on the outer walls of the first side surface 50, the second side surface 60, the third side surface 70, and the upper surface 40. As a result, by forming grid truss ribs 100 on at least three of the side surfaces 50, 60, 70 and the upper surface 40, the overall strength of the battery module can be increased, and its rigidity can be enhanced. Consequently, for example, when mounted on an electric vehicle, deformation can be suppressed even when the battery module 10 is subjected to vibration.

[0030] Furthermore, the battery module of this embodiment has a configuration in which grid truss ribs 100 of the same size are regularly formed on the outer wall of the first side surface 50 facing the cover surface 30. This makes it possible to suppress deformation of the battery module 10 even when it is subjected to vibration, for example, when mounted on an electric vehicle.

[0031] Furthermore, the battery module of this embodiment is provided with a fixing portion 50a that extends from the end of the first side surface 50 to the fixing surface 20 and is fixed thereto. The lattice truss ribs 100 are formed on the outer wall of the first side surface 50 facing the cover surface 30, gradually decreasing in size in the direction of the fixing portion 50a. This allows the battery module 10 to deform even when subjected to vibration, for example, when mounted on an electric vehicle. It also allows for a shape that is less prone to bending under load directed towards the fixing portion 50a, where stress concentration is high.

[0032] Furthermore, the battery module of this embodiment has a configuration in which grid truss ribs 100 are regularly formed on the outer wall of the fixed surface 20. This increases the strength of the fixed surface 20 and improves its rigidity.

[0033] Furthermore, the fixed surface 20 of the battery module in this embodiment is fixed by a first fixing portion 50a extending from the end of the first side surface 50 facing the cover surface 30, and a truss rib is formed on the outer circumference of the first fixing portion 50a. This makes it possible to create a shape that is less likely to bend under load directed toward the first fixing portion 50a where stress concentration is high.

[0034] Furthermore, the fixed surface 20 of the battery module in this embodiment is fixed by three fixing parts 50a, 60a, and 70a extending from the ends of the first side surface 50, the second side surface 60, and the third side surface 70. The first fixing part 50a of the fixed surface 20 extending from the first side surface 50 facing the cover surface 30, the second fixing part 60a of the fixed surface 20 extending from the second side surface 60, and the third fixing part 70a of the fixed surface 20 extending from the third side surface 70 are configured to have truss ribs formed on their outer circumference. This increases the strength of the fixed surface 20 and improves its rigidity.

[0035] Furthermore, the truss ribs 150 of the battery module in this embodiment are formed perpendicular to the fixed surface 20. This increases the strength of the fixed surface 20 and enhances its rigidity.

[0036] The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0037] 10...Battery module, 10aa...First case, 10bb...Second case 20...Fixed surface, 30...Cover surface, 40...Top surface, 50...First side 50a...First fixing part, 60...Second side, 60a...Second fixing part, 70...Third side 70a...Third fixing part, 100...Grid truss rib, 110...Grid-shaped rib 120...Rhombus rib, 150...Truss rib, 200...Battery cell, 210...Spacer

Claims

1. Multiple battery cells, A battery module comprising a box-shaped case in which the aforementioned battery cells are housed, The aforementioned case is, Fixed surface and The upper surface facing the aforementioned fixed surface, A cover surface, a first side surface, a second side surface, and a third side surface that connect the fixed surface and the upper surface, It has, A battery module characterized in that grid truss ribs, consisting of grid-like ribs and rhombus-shaped ribs formed inside the grid-like ribs, are regularly formed on the outer walls of the first side, second side, third side, and top surface.

2. The battery module according to claim 1, characterized in that the lattice truss ribs of the same size are regularly formed on the outer wall of the first side surface facing the cover surface.

3. The battery module according to claim 1, characterized in that a fixing portion is provided that extends from the end of the first side surface to the fixing surface for fixing, and the lattice truss ribs are formed on the outer wall of the first side surface facing the cover surface in a stepwise manner in the direction in which the fixing portion is located.

4. The battery module according to claim 1, characterized in that the grid truss ribs are regularly formed on the outer wall of the fixed surface.

5. The fixing surface is fixed by a first fixing portion extending from the end of the first side surface facing the cover surface. The battery module according to claim 1, characterized in that a truss rib is formed on the outer circumference of the first fixed portion.

6. The aforementioned fixed surface is fixed by three fixing portions extending from the ends of the first side, the second side, and the third side. The battery module according to claim 1, characterized in that a truss rib is formed on the outer circumference of a first fixing portion of the fixing surface extending from the first side surface facing the cover surface, a second fixing portion of the fixing surface extending from the second side surface, and a third fixing portion of the fixing surface extending from the third side surface.

7. The battery module according to claim 5 or 6, characterized in that the truss ribs are formed in a direction perpendicular to the fixed surface.

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