JP6876119B2 - Battery module - Google Patents

Description

The present invention relates to a battery module configured by connecting a plurality of secondary batteries that can be repeatedly charged and discharged.

In recent years, the development of a battery module in which a plurality of lithium ion batteries are connected has been promoted, especially for applications in which a large current is charged and discharged, such as a power supply device for a hybrid vehicle. This battery module can be used alone, but it may also be used as a battery pack by combining a plurality of these modules. When used as a battery pack, it is effective to mount the battery module at a high density from the viewpoint of energy density. As an example of a battery module suitable for such high-density mounting, Patent Document 1 discloses a battery module to which a flat plate-shaped side plate is applied. The battery module disclosed in Patent Document 1 has a configuration in which flat plate-shaped side plates having holes are fastened to flat plate-shaped end plates arranged at both ends in the stacking direction of the battery with bolts. It is effective for high-density mounting because the side plate and end plate for restraining the battery are not bulky.

Japanese Patent Application Laid-Open No. 8-212986

Since the battery module described in Patent Document 1 holds the side surface in the battery stacking direction by a flat plate-shaped side plate, vibration when vibration is applied to the battery module in the direction perpendicular to the battery stacking direction. There was a problem with the countermeasures. That is, since the side plate of the battery module is a flat plate, the side plate is thin, and therefore, it is easy to vibrate with respect to the vibration in the direction perpendicular to the stacking direction of the batteries corresponding to the plate thickness direction of the side plate. It was a composition.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a battery module having improved vibration resistance.

In order to achieve the above object, in the present invention, a battery group in which a plurality of batteries having an upper surface, a lower surface, and a side surface are stacked and a battery group are arranged in front of and behind the stacking direction of the battery group to sandwich the battery group. a pair of end plates fixed to the housing of the battery pack, is disposed facing the side surface of the battery group in the battery module and a pair of side plates that will be secured to the pair of end plates, wherein The side plate has a convex portion in the stacking direction of the battery, and includes a deformation suppressing portion which is a flat plate portion for suppressing deformation of the convex portion along the convex portion, and the flat plate portion sandwiches the convex portion. Provided is a battery module provided in a pair of regions, wherein the width of the flat plate portion on the upper surface side of the convex portion is narrower than the width of the flat plate portion on the lower surface side of the convex portion.

According to the present invention, the rigidity of the side plate can be improved by providing the convex portion on the side plate, and the vibration resistance of the battery module can be improved against vibration in the direction perpendicular to the stacking direction of the battery modules.

The external perspective view which shows the assembled battery which concerns on 1st Embodiment. The disassembled appearance perspective view which shows the assembled battery which concerns on 1st Embodiment. A partial perspective view for explaining the positional relationship between the intermediate holder, the end holder, the end cell, and the end plate. The external perspective view for demonstrating the side plate of the battery module which concerns on 1st Embodiment. The external perspective view for demonstrating the side plate of the battery module which concerns on 1st Embodiment. The external perspective view for demonstrating the side plate of the battery module which concerns on 1st Embodiment. The external perspective view for demonstrating the side plate of the battery module which concerns on 1st Embodiment. The external perspective view for demonstrating the side plate of the battery module which concerns on 1st Embodiment.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings by specific examples, but the present invention is not limited thereto, and is within the scope of the technical idea of the present invention. Other forms considered in the present invention are also included in the scope of the present invention. Further, the drawings in the embodiments are schematic drawings, and the accuracy of the positional relationships and dimensions in the drawings is not guaranteed. Various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed herein. Further, in all the drawings for explaining the present invention, those having the same function may be designated by the same reference numerals, and the repeated description thereof may be omitted.

<< Example 1 >>
FIG. 1 is an external perspective view of the battery module according to the first embodiment of the present invention. Unless otherwise specified, the definition of the direction is up, down, left, right, front and back at the lower left of each figure. FIG. 2 is an exploded external perspective view of the battery module of FIG. However, in FIG. 2, some configurations are omitted.

In the battery module 100 shown in FIG. 1, a battery laminate 1 in which a plurality of battery cells 8 are laminated is sandwiched between a pair of end holders 2 and a pair of end plates 3 which are plate-shaped members, and the pair of side plates 4 sandwich the battery laminate 1. These are integrated, and the intermediate bus bar 5 forms a power line between the batteries, and the end bus bar 6 and the external terminal cable 7 form a power line between the assembled battery and the outside.

The battery laminate 1 will be described with reference to FIGS. 1 and 2. The battery laminate 1 includes a plurality of cell cells 8 and a plurality of intermediate holders 9. Each cell has a flat rectangular parallelepiped shape and has a pair of wide surfaces. The plurality of cells constituting the battery laminate are arranged so that the wide surfaces of the adjacent cell 5s face each other. Adjacent cell cells are arranged in opposite directions so that the positions of the positive electrode terminal and the negative electrode terminal provided on the battery lid are reversed. The positive electrode terminal 81 and the negative electrode terminal 82 of the adjacent cells 8 are electrically connected to each other by an intermediate bus bar 5 which is a flat conductive member made of metal. That is, the plurality of cell cells 8 constituting the battery module 100 according to the present embodiment are electrically connected in series. Further, the positive electrode terminals 81 or the negative electrode terminals 82 of the cell cells 8 at both ends of the battery laminate 1 are provided with end bus bars 6. The end bus bar 6 is electrically connected to the external terminal cable 7 so that electric power can be taken out of the battery module.

Subsequently, the cell 8 constituting the battery laminate 1 will be described with reference to FIG. Each of the plurality of cell batteries 8 has the same structure. The cell 8 includes a square battery container 88 including a battery can 88a and a battery lid 88b. The material of the battery can 88a and the battery lid 88b is, for example, aluminum or an aluminum alloy. The battery can 88a has a rectangular box shape having two large-area surfaces (wide surface 88a1), two small-area surfaces (narrow side surface 88a2), one bottom plate 88a3, and an opening. The battery lid 88b has a rectangular flat plate shape and is laser-welded so as to close the opening of the battery can. That is, the battery lid 88b seals the battery can 88a. The square battery container 88 including the battery lid 88b and the battery can 88a has a hollow rectangular parallelepiped shape.

The battery lid 88b is provided with a positive electrode terminal 81 and a negative electrode terminal 82. Inside the battery container 88, the charge / discharge elements are stored in a state of being covered with an insulating case. The positive electrode of the charge / discharge element is connected to the positive electrode terminal 81, and the negative electrode of the charge / discharge element is connected to the negative electrode terminal 82. The battery lid 88b is provided with a liquid injection hole for injecting the electrolytic solution into the battery container 88. The injection hole is sealed by the injection plug 83 after the electrolytic solution is injected. As the electrolytic solution, for example, a non-aqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF6) is dissolved in a carbonic acid ester-based organic solvent such as ethylene carbonate can be used. The battery lid 88b is provided with a gas discharge valve 84. The gas discharge valve 84 is formed by partially thinning the battery lid 88b by press working. The gas discharge valve 84 is cleaved when the cell cell generates heat due to an abnormality such as overcharging to generate gas and the pressure inside the battery container 88 rises to reach a predetermined pressure, and gas is discharged from the inside. This reduces the pressure inside the battery container 88.

FIG. 3 is a partial perspective view for explaining the positional relationship between the intermediate holder 9, the end holder 2, the cell 8 located at the end of the battery stack, and the end plate 3. The intermediate holder 9, the end holder 2, and the end plate 3 will be described with reference to the drawings.

A plurality of intermediate holders 9 are laminated in the front-rear direction of the battery laminate 1. The material of the intermediate holder 9 is a resin having insulating properties and heat resistance, such as engineering plastics such as polybutylene terephthalate (PBT) and polycarbonate (PC), and rubber. Since the intermediate holder 9 is interposed between the cells, the insulation between the adjacent cells 8 is ensured. The intermediate holder 9 has an isolation portion 9A and a connecting portion 9B. The isolation portion 9A faces the wide surface 88a1 of the battery and prevents the wide surfaces 88a1 of two adjacent batteries from coming into contact with each other. The connecting portion 9B has a peak portion and a valley portion, and is used for connecting to an adjacent intermediate holder and an end holder described later.

The end holder 2 is arranged between the cell 8 and the end plate 3 arranged at the front end of the battery stack, and between the cell 8 and the end plate 3 arranged at the rear end. Since the end holder 2 is interposed between the cell 8 and the end plate 3, the insulation between the end plate and the cell 8 is ensured.

The end holder 2 arranged at the end of the battery laminate 1 has an isolation portion 2A, a connecting portion 2B, and a fixing portion 2C. The isolation portion 2A faces the wide surface of the cell 8 and the end plate 3 to prevent the wide surface of the battery from coming into contact with the end plate. The connecting portion 2B has a peak portion and a valley portion, and is used for connecting with an adjacent intermediate holder.
The fixing portion 2C protrudes from the isolation portion 2A of the end holder toward the end plate 3. The fixed portion 2C is a portion for fastening the end bus bar 6 and the external terminal cable 7 and electrically connecting them, and the insert nut 10 is integrated with the fixed portion 2C. Although the insert nut 10 is used in this embodiment, the structure may be such that the insert bolt is integrated. The fixing portion 2C is configured to be inserted into the accommodating portion 3A of the end plate 3 described later, and transmits the rotational torque applied to the fixing portion to the end plate when the end bus bar 6 and the external terminal cable 7 are fastened. Therefore, the stability of the fixed portion 2C is ensured.

Adjacent intermediate holders, or between the intermediate holder and the end holder, are connected by fitting the connecting portions of the respective holders. Specifically, by fitting the connecting portion 9B of the intermediate holder 9 and the connecting portion 9B of the adjacent intermediate holder, the adjacent intermediate holders 9 are connected to each other, and the connecting portion 9B of the intermediate holder 9 and the end holder 2 are connected. By fitting the portion 2B, the intermediate holder 9 and the end holder 2 are connected to each other.

The end plate 3 has a rectangular flat plate shape and is formed to have substantially the same size as the cell 8. The end plates 3 are arranged at the front and the rear of the battery stack 1 in the stacking direction, and sandwich the battery stack 1 via a pair of end holders. The accommodating portion 3A has a shape in which the upper surface of the end plate 3 is recessed, and a part of the recess is opened to the end holder 2 side. The shape of the accommodating portion 3A is substantially the same as that of the fixing portion 2C, and the fixing portion 2C is accommodated in the accommodating portion 3A. The end plate 3 has an end plate fastening portion 3B protruding in the direction opposite to that of the battery laminate 1. The end plate fastening portion 3B has a fastening hole 3C, and a bolt is passed through the fastening hole to fix the end plate 3 to the housing (not shown) of the battery pack. By fixing the end plate 3 to the battery pack housing in this way, the battery module 100 is fixed to the battery pack housing on the bottom side. The material of the end plate 3 is a metal such as aluminum or an aluminum alloy.

Subsequently, FIG. 4 shows the shape of the side plate 4, which is a feature of the present invention. The side plates 4 are arranged symmetrically on the left and right sides of the battery stack 1 in the stacking direction. Therefore, in FIG. 4, the side plate 4 on one side is taken out and described. The side plate 4 is physically connected to the pair of end plates 3 by bolts 11. The side plate 4 is manufactured by using a metal plate such as a stainless steel plate or a steel plate having a predetermined thickness.

The side plate 4 does not have a flat plate shape, but has a convex portion 4A protruding in the plate thickness direction (right direction) of the side plate. The convex portion 4A is formed from end to end of the side plate 4 along the longitudinal direction of the battery module, that is, the stacking direction (front-back direction) of the batteries. The convex portion can be formed by various methods. For example, in the side plate 4 shown in FIG. 4, the convex portion 4A is formed by subjecting one plate to a bending process, a drawing process, or the like. The fastening hole 4B for connecting the side plate 4 to the end plate 3 is limited in position in order to avoid interference between the convex portion 4A and the bolt, and is between the convex portion 4A and the end of the side plate, or the convex portion 4A. It is installed on the top of.

The convex portion 4A can improve the vibration resistance of the side plate against vibration in the direction perpendicular to the longitudinal direction (left-right direction) of the battery module 100. Further, a flat plate portion 4C is formed in the region sandwiching the convex portion 4A, and the flat plate portion can suppress deformation of the side plate due to the formation of the convex portion. If the side plate 4 is formed in a continuous uneven shape (bellows shape) without the flat portion 4C, the rigidity in the left-right direction becomes low, and as described above, it becomes vulnerable to vibration in the left-right direction. In this embodiment, since a pair of flat portions 4C are provided so as to sandwich the convex portion, they are strong against vibration in the left-right direction. The flat portion 4C does not have to have a completely flat shape as compared with the convex portion 4A, but the flat portion 4C is more resistant to vibrations from various directions, so that vibrations in the left-right direction are more likely to occur. It is preferable in terms of suppressing.

Subsequently, a method of integrating the battery laminate 1, the end holder 2, and the end plate 3 will be described. In order to integrate the battery laminate 1, the end holder 2 and the end plate 3, the battery laminate 1 is placed in the end holder 2 with the end holder 2 in contact with the front and rear of the battery laminate 1 in the stacking direction. The whole is sandwiched between the end plates 3, and then the pair of side plates 4 are screwed to the end plates 3 with bolts 11. When the side plate 4 is screwed to the end plate 3 with bolts 11, the battery laminate sandwiched between the pair of end plates and the end cell holder are held in a state of being compressed by a predetermined amount. In the present embodiment, the method of fixing the side plate to the end plate using bolts has been described, but the side plate may be fixed to the end plate by using rivets, caulking, welding, or the like. ..

<< Modification 1 >>
Here, a modified example of the side plate of the present invention will be described with reference to FIGS. 5 to 8.

First, FIG. 5 shows the side plate 12 of the modified example 1. The difference between this modification and the side plate 12 of the first embodiment is that a plurality of convex portions are provided.

As described above, the side plate 12 shown in FIG. 5 is provided with a plurality of convex portions 12A. By increasing the number of convex portions in this way, the seismic resistance of the side plate can be improved.

Subsequently, FIG. 6 shows the side plate 12 of the modified example 2. The difference between this modification and the side plate 12 of the first embodiment is that a plurality of convex portions are provided and the outer periphery of the convex portions is entirely surrounded by the flat portion 13.

As described above, the side plate 13 of FIG. 6 is provided with the flat plate portions 13D at both ends in the longitudinal direction (both ends in the front-rear direction) in addition to the flat plate portions 13C formed along the longitudinal direction (along the front-rear direction). .. By doing so, since the periphery of the convex portion 13A is entirely covered with the flat plate portion, the deformation of the side plate due to the formation of the convex portion can be further suppressed. In particular, since the flat portion 13D continuously connects the convex portions 13A, the structure is stronger against twisting in the vertical direction than in the first embodiment. Further, the fastening holes 13B for connecting the side plate 13 to the end plate 3 by providing the flat plate portions 13D at both ends in the longitudinal direction can be provided at any position without limiting the position. Therefore, the degree of freedom in design is improved.

Subsequently, FIG. 7 shows the side plate 14 of the modified example 3. The difference between this modification and the side plate of the first embodiment is that the convex portion is arranged on the upper side of the side plate 14.

As described above, the side plate 14 of FIG. 7 is provided with the convex portion 14A at a position biased toward the upper surface of the battery module. Therefore, the structure is such that the upper flat portion 14C1 having a width narrower than that of the lower flat portion 14C2 is provided. Since the bottom surface of the battery module 100 of this embodiment is fixed to the housing of the battery pack, when vibration is applied to the battery module, the top surface is more likely to vibrate than the bottom surface. Therefore, by biasing the convex portion toward the upper surface as shown in FIG. 7, the vibration resistance can be improved more efficiently.

Finally, FIG. 8 shows the side plate 15 of the modified example 4. The difference between this modification and the side plate of the first embodiment is that the convex portion is made of a separate member.

As described above, the side plate 15 of FIG. 8 has a structure in which the convex portion 15A manufactured by another member is integrated with the flat plate portion 15C. The material of the convex portion 15A is not limited, and can be made of metal or resin. When the convex portion is metal, it can be integrated with the flat plate portion 15C by welding, for example, and when the convex portion is resin, it can be integrated with the flat plate portion 15C by, for example, an adhesive. By using the convex portion as a separate member, the shape of the convex portion and the position of the convex portion can be freely designed as compared with the case where the convex portion is manufactured by bending or drawing.
The present invention will be briefly summarized above. The battery module 100 according to the present invention includes a battery group (1) in which a plurality of batteries having an upper surface (88b), a lower surface (88a3), and side surfaces (88a1, 88a2) are stacked, and a side surface of the battery group (1). A pair of side plates (4) arranged to face each other are provided, and the side plate (4) has a convex portion (4A) and suppresses deformation of the convex portion (4A) along the convex portion (4A). The deformation suppressing portion (4C, 12C, 13C, 14C, 15C) is provided, and the deformation suppressing portion (4C, 12C, 13C, 14C, 15C) is provided in a pair of regions sandwiching the convex portion (4A). To do. With such a configuration, the effect of suppressing vibration in the left-right direction is improved.

Further, in the battery module 100 described in the present invention, the deformation suppressing portion is, for example, a flat plate portion (4C, 12C, 13C, 14C, 15C).

Further, in the battery module 100 described in the present invention, as an example, a pair of flat plate portions (4C, 12C, 13C, 14C, 15C) and convex portions are arranged in a direction from the upper surface to the lower surface of the battery. As another example, there is a structure in which a pair of flat plate portions (4C) and convex portions are lined up in the direction from the front to the rear of the battery, but as in this embodiment, the bottom surface of the battery module 100 is a housing of the battery pack. Since it is more important to suppress vibration in the left-right direction in a structure fixed to the body, a pair of flat plate portions (4C, 12C, 13C, 14C, 15C) and convex portions are lined up in the direction from the upper surface to the lower surface of the battery. The structure is preferable.

Further, the battery module 100 described in the present invention has a configuration in which the width of the flat plate portion (14C1) on the upper surface side is narrower than the width of the flat plate portion (14C2) on the lower surface side. Since the bottom surface of the battery module 100 is fixed to the housing of the battery pack, when vibration is applied to the battery module, the top surface is more likely to vibrate than the bottom surface. Therefore, by biasing the convex portion toward the upper surface in this way, the vibration resistance can be improved more efficiently.

Further, the battery module 100 described in the present invention is characterized in that the convex portions (12A, 13A) are composed of a plurality of convex portions. With such a structure, the rigidity of the side plate is improved and the vibration resistance is improved.

According to the present embodiment described above, the following effects can be obtained. In the present embodiment, the rigidity of the side plate can be improved by providing the side plate with a convex portion, and the vibration resistance of the battery module can be improved against vibration in the direction perpendicular to the stacking direction of the battery modules.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs are designed without departing from the spirit of the present invention described in the claims. You can make changes. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 Battery laminate 2 End holder 2A Isolation part 2B Connecting part 2C Fixing part 3 End plate 3A Accommodating part 3B End plate fastening part 3C Fastening hole 4 Side plate 5 Intermediate bus bar 6 End bus bar 7 External terminal cable 8 Single battery 9 Intermediate holder 9A Isolation part 9B Connecting part 10 Insert nut 11 Bolt 12 Side plate 12A Convex part 12B Fastening hole 12C Flat plate part 13 Side plate 13A Convex part 13B Fastening hole 13C Flat plate part 14 Side plate 14A Convex part 14B Fastening hole 14C Flat plate part 15 Side plate 15A Convex part 15B Fastening hole 15C Flat plate part

Claims (4)

A group of batteries in which a plurality of batteries having an upper surface, a lower surface, and a side surface are stacked, and
A pair of end plates arranged in front of and behind the stacking direction of the battery group, sandwiching the battery group, and fixed to the housing of the battery pack.
Wherein disposed facing the side surface of the battery group in the battery module and a pair of side plates that will be secured to the pair of end plates,
The side plate has a convex portion in the stacking direction of the battery, and includes a deformation suppressing portion which is a flat plate portion that suppresses deformation of the convex portion along the convex portion.
The flat plate portion is provided in a pair of regions sandwiching the convex portion.
A battery module characterized in that the width of the flat plate portion on the upper surface side of the convex portion is narrower than the width of the flat plate portion on the lower surface side of the convex portion. In the battery module according to claim 1,
A battery module characterized in that the pair of flat plate portions and the convex portions are arranged in a direction from the upper surface to the lower surface of the battery. In the battery module according to claim 2.
A battery module characterized in that the pair of flat plate portions and the convex portions are arranged in the stacking direction of the batteries. In the battery module according to any one of claims 1 to 3.
A battery module characterized in that the convex portion is composed of a plurality of convex portions.

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