Structure and method for fixing battery module to battery pack

Abstract

To provide a fixing structure that can fix a battery module to a battery pack in a more preferable manner.SOLUTION: A structure for fixing a battery module 1 to a battery pack P according to the present disclosure is such that a main housing 10 of the battery module 1 has a plurality of cell accommodating holes 10a for accommodating battery cells 11, and in at least one of the plurality of cell accommodating holes 10a, the battery cells 11 are not placed and a screw receiving member 12 is arranged in place of the battery cells 11, and a screw member Ba is arranged so as to pass through a through hole 10b formed in the side wall of the main housing 10 via a bracket Pb fixed to the battery pack P, and the main housing 10 is fixed to the battery pack P by fastening to the screw hole 12a of the screw receiving member 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a structure and a method for fixing a battery module to a battery pack. [Background technology]

[0002] Secondary batteries are used in a variety of devices, including not only portable devices but also electric vehicles, hybrid vehicles, etc. Lithium-ion batteries, in particular, are attracting attention as a new energy source due to their high energy density, compact size, and light weight.

[0003] The battery cells of such secondary batteries generally have an operating voltage of about 3V. Therefore, when a higher output voltage is required, a plurality of battery cells are connected in series to form a battery pack. Alternatively, a plurality of battery cells may be connected in parallel to form a battery pack depending on the required charge / discharge capacity. In this way, the number of battery cells included in a battery pack is determined in various ways depending on the required output voltage and charge / discharge capacity. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2020-514978 Summary of the Invention [Problem to be solved by the invention]

[0005] This type of battery pack is generally constructed by connecting a plurality of battery modules, each housing a large number of battery cells (see, for example, Patent Document 1). Each battery module is usually configured with a fastening structure on the outer side surface of the main body housing of the battery module, and the fastening structure fastens the battery pack or other battery modules to the battery module.

[0006] However, with this configuration, the size of the main body housing of the battery module increases by the amount of the fastening structure provided on the outer side surface. In other words, this means that the size of the entire battery pack increases. This means that the energy density decreases, which is a major problem in electric vehicles and the like, where maximizing energy density within a limited space is an urgent issue.

[0007] Furthermore, with this configuration, it is necessary to design a fastening structure specifically for each battery pack variation, which increases the cost of manufacturing the battery modules. In particular, in a vehicle, the positions at which the battery modules are fixed to the battery pack and the number of fixing screws are designed taking into consideration the expected vibration patterns (i.e., vibration direction and vibration acceleration) of the vehicle and interference with other mounted equipment. Furthermore, the manner in which the battery modules are fixed to the battery pack also varies depending on the number of battery modules mounted in the battery pack and the layout of the battery modules within the battery pack. In such cases, if a fastening structure for the battery module is designed specifically for each type of battery pack, the number of types of battery modules will increase, leading to an increase in the number of types of battery modules and an increase in product manufacturing costs.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a fixing structure and fixing method that can fix a battery module to a battery pack in a more preferable manner. [Means for solving the problem]

[0009] The present disclosure mainly solves the above-mentioned problems by: A structure for fixing a battery module to a battery pack, the main body housing of the battery module has a plurality of cell receiving holes for receiving battery cells, the battery cell is not placed in at least one of the plurality of cell accommodating holes, and a screw receiving member is placed in place of the battery cell; A screw member is arranged to pass through a through-hole formed in a side wall of the main body housing via a bracket fixed to the battery pack, and the main body housing is fixed to the battery pack by fastening it to a screw hole of the screw receiving member. It is a fixed structure.

[0010] In other respects, A method for fixing a battery module to a battery pack, comprising: providing a main body housing of the battery module having a plurality of cell receiving holes for receiving respective battery cells; placing the battery module in the battery pack in a state in which the battery cells are not placed in at least one of the plurality of cell accommodating holes and a screw receiving member is placed in place of the battery cell; a step of inserting a screw member through a through hole formed in a side wall of the main body housing via a bracket for fixing to the battery pack, and fastening the screw member to a screw hole of the screw receiving member; This is a fixing method having the following. [Effects of the Invention]

[0011] The structure for fixing a battery module to a battery pack according to the present invention is more suitable in terms of miniaturizing the battery module and accommodating various designs of the battery pack. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating a state in which a battery module is housed in a battery pack according to an embodiment of the present invention. [Figure 2] FIG. 1 is a plan view showing a state in which battery cells are housed in cell housing holes of a battery module according to an embodiment of the present invention; [Figure 3] FIG. 1 is a view showing battery cells housed in cell housing holes of a battery module according to an embodiment of the present invention, viewed obliquely from above; [Figure 4] FIG. 1 is a plan view illustrating a configuration of cell receiving holes and through holes formed in a main body housing of a battery module according to an embodiment of the present invention; [Figure 5] FIG. 10 is a diagram showing a modified example of the structure for fixing the battery module to the battery pack; [Figure 6] FIG. 10 is a diagram showing the configuration of a screw receiving member according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functions are designated by the same reference numerals, and redundant description will be omitted.

[0014] In each figure, a common Cartesian coordinate system (X, Y, Z) is shown to clarify the positional relationship of each component. The positive direction of the Z axis represents the upward direction of the battery pack, and the X and Y axes represent the lateral directions of the battery pack that are perpendicular to the Z axis. However, these directions do not limit the posture of the battery pack of the present invention during use.

[0015] The following describes the configuration of a battery pack (hereinafter referred to as "battery pack P") according to one embodiment of the present invention, and an example of a structure for fixing a battery module (hereinafter referred to as "battery module 1") to the battery pack P. The battery pack P according to this embodiment is mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle, and is used as a driving power source for the vehicle.

[0016] Fig. 1 is a diagram showing a state in which a battery module 1 is accommodated in a battery pack P. Fig. 2 is a plan view showing a state in which battery cells 11 are accommodated in the cell accommodating holes 10a of the battery module 1. Fig. 3 is a diagram showing a state in which battery cells 11 are accommodated in the cell accommodating holes 10a of the battery module 1 as viewed obliquely from above.

[0017] Fig. 4 is a plan view showing the configuration of the cell accommodating holes 10a and through holes 10b formed in the main body housing 10 of the battery module 1. Note that Fig. 4 omits illustration of configurations other than the cell accommodating holes 10a and through holes 10b.

[0018] The battery pack P has, for example, a rectangular box-shaped main body case Pa, and houses a plurality of battery modules 1 inside the main body case Pa. Each battery module 1 is fastened and fixed to the main body case Pa of the battery pack P by a bracket Pb and a bolt Ba. The plurality of battery modules 1 are electrically connected to one another by extraction electrodes (not shown) or the like.

[0019] The multiple battery modules 1 housed in the battery pack P have, for example, approximately the same configuration. The following describes the configuration of only one battery module 1. For ease of explanation, only one battery module 1 is depicted in FIG. 1.

[0020] The battery module 1 includes a main body housing 10, a plurality of battery cells 11, a screw receiving member 12, a bus bar 13, and the like.

[0021] The battery cell 11 is, for example, a cylindrical battery cell. The battery cell 11 has, for example, a cylindrical case containing a positive electrode, a negative electrode, and a separator, each of which is in the form of a sheet, as well as an electrolyte. The battery cell 11 has a structure in which, for example, the positive electrode and the negative electrode face each other with the separator in between, and the electrolyte is disposed between them.

[0022] The battery cell 11 has, for example, a positive electrode terminal on its upper surface (the surface facing the positive Z direction) and a negative electrode terminal on its lower surface (the surface facing the negative Z direction). The positive electrode terminal is connected to a positive electrode inside the battery cell 11, and the negative electrode terminal is connected to a negative electrode inside the battery cell 11.

[0023] The battery cells 11 are, for example, lithium ion batteries, but may also be other types of secondary batteries, such as nickel-cadmium batteries, nickel-metal hydride batteries, or nickel-zinc batteries.

[0024] The multiple battery cells 11 mounted in the battery module 1 typically have the same configuration. The multiple battery cells 11 are individually housed in an upright state within the cell housing holes 10a of the main body housing 10. That is, each battery cell 11 is housed within the cell housing holes 10a of the main body housing 10 with its positive and negative terminals facing in the ±Z directions.

[0025] The positive electrode terminal of each of the plurality of battery cells 11 is connected to, for example, a positive electrode bus bar 13. The negative electrode terminal of each of the plurality of battery cells 11 is connected to, for example, a negative electrode bus bar 13.

[0026] The main body housing 10 is a holder for supporting multiple battery cells 11. The main body housing 10 is made of, for example, an insulating resin material (e.g., ABS resin or PBT resin). The main body housing 10 has, for example, a rectangular parallelepiped block shape.

[0027] The main body housing 10 has a plurality of cell accommodating holes 10a for accommodating a plurality of battery cells 11, respectively. Each of the cell accommodating holes 10a has a shape that is substantially the same as the outer shape of the battery cells 11, e.g., a cylindrical shape. That is, each of the cell accommodating holes 10a has a substantially identical shape. The cell accommodating holes 10a are formed along the ±Z directions so as to penetrate the top and bottom surfaces of the main body housing 10. In other words, the cell accommodating holes 10a are arranged so that their circular openings are aligned within the main body housing 10 in a plan view.

[0028] A positive electrode bus bar 13 is disposed on the upper surface of the main body housing 10 so as to cover the cell accommodating hole 10a, and an upper cover 10c is disposed above the positive electrode bus bar 13. A negative electrode bus bar 13 is disposed on the lower surface of the main body housing 10 so as to cover the cell accommodating hole 10a, and a lower cover (not shown) is disposed below the negative electrode bus bar 13.

[0029] The positive electrode bus bar 13, for example, electrically connects the positive electrode terminals of each of the multiple battery cells 11. The positive electrode bus bar 13 is disposed, for example, so as to cover the upper part of the cell accommodating hole 10a of the main body housing 10. The negative electrode bus bar 13, for example, electrically connects the negative electrode terminals of each of the multiple battery cells 11. The negative electrode bus bar 13 is disposed, for example, so as to cover the lower part of the cell accommodating hole 10a of the main body housing 10. Note that the negative electrode bus bar 13 is not shown in the drawings.

[0030] The positive electrode bus bar 13 is connected to a positive electrode extraction electrode (not shown) and is electrically connected via this extraction electrode to the positive electrode bus bar 13 of another battery module 1. The negative electrode bus bar 13 is connected to a negative electrode extraction electrode (not shown) and is electrically connected via this extraction electrode to the negative electrode bus bar 13 of another battery module 1.

[0031] A through hole 10b is formed in the side wall of the main body housing 10 so as to communicate with one of the cell accommodating holes 10a. In this embodiment, a large number of through holes 10b are formed in the side wall of the main body housing 10, and the position at which the main body housing 10 is fastened to the main body case Pa of the battery pack P (i.e., the position at which it is fastened to the bracket Pb) can be freely set using a bolt Ba. Specifically, in this embodiment, a plurality of through holes 10b are formed in each of the positive X side wall, negative X side wall, positive Y side wall, and negative Y side wall of the main body housing 10 (see FIG. 4). Each of these plurality of through holes 10b is formed so as to communicate with one of the plurality of cell accommodating holes 10a.

[0032] The bolts Ba are inserted into, for example, one to eight of the multiple through holes 10b formed in the side wall of the main housing 10. In other words, the hole group structure of the through holes 10b formed in the main housing 10 is intended to enable the fastening position of the bolts Ba to be set at any position on the main housing 10, and is configured to enable a common battery module 1 to be applied regardless of the type of battery pack P.

[0033] Furthermore, the position where the main housing 10 and the main case Pa of the battery pack P are fastened together (i.e., the position where the main housing 10 and the bracket Pb are fastened together) is the position where the screw receiving member 12 is arranged among the multiple cell accommodating holes 10a formed in the main housing 10.

[0034] The screw receiving member 12 is disposed in one of the multiple cell receiving holes 10a that is formed at a position where the main body housing 10 and the bracket Pb are fastened together. The screw receiving member 12 has a shape that conforms to the inner shape of the cell receiving hole 10a. Figures 2 and 3 show an example of the shape of the screw receiving member 12, which has a substantially arc shape in a plan view. The screw receiving member 12 is formed, for example, from steel to ensure strength.

[0035] The screw receiving member 12 has a threaded hole 12a for fastening to a bolt Ba, and is fastened to the bolt Ba inserted through the through hole 10b from the outside of the side wall of the main body housing 10. That is, the threaded hole 12a of the screw receiving member 12 is formed at a position communicating with the through hole 10b formed in the side wall of the main body housing 10.

[0036] Here, the cell accommodating holes 10a in which the screw receiving members 12 are disposed are used for fastening, and no battery cells 11 are disposed in these cell accommodating holes 10a. That is, all of the multiple cell accommodating holes 10a formed in the main body housing 10 are formed to accommodate battery cells 11, but some of the multiple cell accommodating holes 10a are used for fastening. Therefore, screw receiving members 12 are disposed in place of battery cells 11 in those of the multiple cell accommodating holes 10a used for fastening. Battery cells 11 are disposed only in the remaining cell accommodating holes 10a of the multiple cell accommodating holes 10a. In other words, bolts Ba are selectively inserted only into those of the multiple through holes 10b selected as fastening positions.

[0037] 1, fastening portions for fastening with bolts Ba are provided at four locations on the side surface on the plus X side and at four locations on the side surface on the minus X side. That is, in the battery module 1 shown in FIG. 1, screw receiving members 12 are disposed in the eight cell accommodating holes 10a that correspond to the fastening portions, and battery cells 11 are disposed in the remaining cell accommodating holes 10a.

[0038] The number and positions of the cell accommodating holes 10a used for fastening and fixing among the multiple cell accommodating holes 10a formed in the main body housing 10 differ depending on the type of battery pack P. This is because, as described above, the fixing positions of the battery modules 1 to the battery pack P and the number of fixing screws are designed for each type of battery pack P.

[0039] A bolt Ba (corresponding to the "screw member" of the present invention) is arranged to pass through a through hole 10b formed in the side wall of the main body housing 10 via a bracket Pb fixed to the battery pack P. The bolt Ba is fastened to a screw hole 12a formed in the screw receiving member 12, thereby fixing the main body housing 10 to the battery pack P. The bracket Pb is, for example, an L-shaped bracket with an L-shaped cross section, and a first mounting surface Pb1 is attached to the side surface of the main body housing 10 by the bolt Ba, and a second mounting surface Pb2 is attached to the bottom surface of the main body case Pa of the battery pack P by a bolt Bb.

[0040] A reinforcing annular spacer 10bb is fitted into the through hole 10b formed in the side wall of the main body housing 10. The spacer 10bb is made of, for example, steel, and prevents the main body housing 10 from being distorted by stress acting on the resin main body housing 10 from the bearing surface of the bolt Ba when the bolt Ba is fastened to the screw receiving member 12.

[0041] <Fixing battery module 1 to battery pack P> Next, a description will be given of the work of fixing the battery module 1 to the battery pack P. Note that this fixing work is performed, for example, manually by a worker.

[0042] First, the worker prepares the main body housing 10 of the battery module 1, which has cell accommodating holes 10a and through-holes 10b formed in advance. Then, the worker places the negative electrode bus bar 13 and the bottom cover on the underside of the main body housing 10 so as to cover the cell accommodating holes 10a, and supports the battery cells 11 within the cell accommodating holes 10a.

[0043] Next, the worker recognizes the positions of the fastening parts among the multiple cell accommodating holes 10a formed in the main body housing 10, and places screw receiving members 12 in the fastening cell accommodating holes 10a among the multiple cell accommodating holes 10a, and places battery cells 11 in the other cell accommodating holes 10a among the multiple cell accommodating holes 10a. The worker then places the positive electrode bus bar 13 and the top cover 10c on the top side of the main body housing 10 so as to cover the cell accommodating holes 10a.

[0044] Next, the worker attaches the fixing bracket Pb to the side surface of the main body housing 10. At this time, the worker presses the first mounting surface Pb1 of the bracket Pb against the side wall of the main body housing 10, and inserts the bolt Ba from the outside of the main body housing 10 into the bolt insertion hole formed in the first mounting surface Pb1 of the bracket Pb, and then inserts the bolt Ba into the through hole 10b formed in the side wall of the main body housing 10. Then, the worker inserts the bolt Ba into the cell accommodating hole 10a up to the position of the screw hole 12a of the screw receiving member 12. Then, the worker tightens the bolt Ba into the screw hole 12a of the screw receiving member 12 using a power tool or the like.

[0045] Next, the worker places the battery module 1 inside the main body case Pa of the battery pack P. Then, the worker attaches the second mounting surface Pb2 of the bracket Pb to the bottom surface of the battery pack P with the bolt Bb. Specifically, the worker inserts the bolt Bb into a bolt insertion hole formed in the second mounting surface Pb2 of the bracket Pb. Then, the worker tightens the bolt Bb into a screw hole formed in the bottom surface of the main body case Pa using a power tool or the like.

[0046] Through the steps described above, the battery module 1 is fixed to the battery pack P.

[0047] <Effects> As described above, in the structure for fixing the battery module 1 to the battery pack P according to this embodiment, The main body housing 10 of the battery module 1 has a plurality of cell accommodating holes 10a for accommodating the respective battery cells 11, In at least one of the plurality of cell accommodating holes 10a, a battery cell 11 is not placed, and a screw receiving member 12 is placed in place of the battery cell 11; The screw member Ba is arranged to pass through a through hole 10b formed in the side wall of the main housing 10 via a bracket Pb fixed to the battery pack P, and the main housing 10 is fixed to the battery pack P by fastening it to a screw hole 12a provided in the screw receiving member 12.

[0048] In other words, the fixing structure of the battery module 1 to the battery pack in this embodiment does not arrange a fastening structure on the outer wall side of the main housing 10, but rather adopts a configuration in which the fastening structure is incorporated into the cell accommodating holes 10a inside the main housing 10 (i.e., a screw receiving member 12 is arranged in at least one cell accommodating hole 10a).

[0049] This allows the main body housing 10 itself to be configured with the minimum thickness required to support the battery cells 11. In other words, this allows the battery module 1 as a whole to be made smaller in size.

[0050] In addition, according to the structure for fixing the battery module 1 to the battery pack P according to this embodiment, a fastening structure for the battery pack P can be configured without special processing being performed on the main body housing 10 itself. This makes it possible to use a common battery module 1 for battery packs P with various layouts. In other words, this makes it possible to reduce mold costs by standardizing specifications.

[0051] <Modification> Fig. 5 is a diagram showing the configuration of a modified example of the structure for fixing the battery module 1 to the battery pack P. Fig. 5 is a plan view showing the state in which battery cells 11 are housed in the cell housing holes 10a of the battery module 1. Fig. 6 is a diagram showing the configuration of a screw receiving member 12 according to the modified example.

[0052] The fixing structure of the battery module 1 to the battery pack P in this modified example differs from the fixing structure in the above embodiment in that the screw receiving member 12 is composed of a block member having approximately the same external shape as the battery cell 11.

[0053] Specifically, the screw receiving member 12 according to this modification has a cylindrical shape that conforms to the shape of the cell accommodating hole 10a. Also, a slit 12b is formed on the upper surface of the screw receiving member 12 according to this modification.

[0054] In the fixing structure according to the above embodiment, during the bolt tightening operation, the worker must align the height and orientation of the screw receiving member 12 within the cell accommodating hole 10a while supporting the screw receiving member 12 so that the screw hole 12a of the screw receiving member 12 communicates with the through hole 10b. Then, with the screw receiving member 12 held in an appropriately aligned position within the cell accommodating hole 10a, the worker must insert the bolt Ba into the through hole 10b.

[0055] In this regard, by configuring the screw receiving member 12 from a block member with approximately the same external shape as the battery cell 11, the screw receiving member 12 is supported on the bottom cover within the cell accommodating hole 10a in the same way as the battery cell 11. In other words, during bolt tightening work, the worker only needs to adjust the orientation of the screw receiving member 12 so that the screw hole 12a of the screw receiving member 12 communicates with the through hole 10b; at this time, the worker does not need to support the screw receiving member 12.

[0056] At this time, the orientation of the screw receiving member 12 can be adjusted using slits 12b formed on the upper surface of the screw receiving member 12. That is, by fitting a tool such as a screwdriver into the slit 12b, the worker can easily rotate the screw receiving member 12 in the cell accommodating hole 10a with the tool.

[0057] In this way, the structure for fixing the battery module 1 to the battery pack P according to this modified example can improve the workability of the bolt tightening work.

[0058] However, from the viewpoint of weight reduction, the plate member described in the above embodiment is preferable as the screw receiving member 12. Therefore, whether to adopt the block member according to this modified example or the plate member described in the above embodiment as the screw receiving member 12 is preferably selected in consideration of the manner in which the battery pack P is used, etc.

[0059] 5 and 6 show an embodiment in which the orientation of the screw receiving member 12 can be adjusted by using the slits 12b formed on the upper surface of the screw receiving member 12, but instead of the slits 12b, protrusions may be formed on the upper surface of the screw receiving member 12.

[0060] 5 and 6 show an embodiment in which the screw receiving member 12 has a cylindrical shape, but the screw receiving member 12 may have a cylindrical shape with a hollow center.

[0061] <Other embodiments> The present invention is not limited to the above-described embodiment, but can be applied to various modified embodiments.

[0062] For example, in the above embodiment, a cylindrical battery cell in which a positive electrode terminal is disposed on the upper side of the battery cell 11 and a negative electrode terminal is disposed on the lower side of the battery cell 11 is shown as an example of the configuration of the battery cell 11. However, the battery cell 11 applied to the present invention may also be a cylindrical battery cell in which both the positive electrode terminal and the negative electrode terminal are formed on the upper side.

[0063] In the above embodiment, a screw hole structure formed in the screw receiving member 12 itself has been shown as an example of the screw hole 12a formed in the screw receiving member 12. However, the screw hole 12a may be formed by a welded nut or the like fixed to the screw receiving member 12.

[0064] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. [Industrial Applicability]

[0065] The structure for fixing a battery module to a battery pack according to the present invention is more suitable in terms of miniaturizing the battery module and accommodating various designs of the battery pack. [Explanation of symbols]

[0066] 1 Battery Module 10 Main body housing 10a Cell housing hole 10b through hole 10bb spacer 10c Top cover 11 Battery Cells 12 Screw receiving member 12a screw hole 12b Slit 13 Busbar Ba, Bb bolt P Battery pack Pa main body case Pb bracket

Claims

1. A structure for fixing a battery module to a battery pack, the main body housing of the battery module has a plurality of cell receiving holes for receiving battery cells, the battery cell is not placed in at least one of the plurality of cell accommodating holes, and a screw receiving member is placed in place of the battery cell; A screw member is arranged to pass through a through-hole formed in a side wall of the main body housing via a bracket fixed to the battery pack, and the main body housing is fixed to the battery pack by fastening it to a screw hole of the screw receiving member. Fixed structure.

2. The battery cell has a cylindrical shape, Each of the plurality of cell accommodating holes has a cylindrical shape that conforms to the outer shape of the battery cell. The fixing structure according to claim 1 .

3. The screw receiving member has a shape that conforms to the inner circumferential surface of the at least one cell receiving hole. The fixing structure according to claim 2 .

4. The screw receiving member has a cylindrical shape. The fixing structure according to claim 3 .

5. A slit or a protrusion is formed on the upper surface of the screw receiving member. The fixing structure according to claim 4.

6. a plurality of through holes are formed in a side wall of the main body housing, each of the through holes communicating with one of the plurality of cell accommodating holes; The screw member is selectively inserted into only one of the through holes selected as a fastening and fixing position among the plurality of through holes. The fixing structure according to claim 1 .

7. A method for fixing a battery module to a battery pack, comprising: providing a main body housing of the battery module having a plurality of cell receiving holes for receiving respective battery cells; placing the battery module in the battery pack in a state in which the battery cells are not placed in at least one of the plurality of cell accommodating holes and a screw receiving member is placed in place of the battery cell; a step of inserting a screw member through a through hole formed in a side wall of the main body housing via a bracket for fixing to the battery pack, and fastening the screw member to a screw hole of the screw receiving member; A fixing method having the following features.

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