Battery pack

Abstract

To provide a battery pack capable of increasing a proper value of the battery pack while hardly transmitting an external input to a battery cell.SOLUTION: A battery pack comprises: a plurality of battery modules; a battery pack case; and a plurality of brackets. The plurality of battery modules is arranged in parallel along a column direction. The battery pack case is attached to a vehicle body, and houses the plurality of battery modules. The plurality of brackets fixes the plurality of battery modules to the battery pack case. The column direction is a direction orthogonal to a longer direction of each of the plurality of battery modules. Each of the plurality of battery modules contains a fixing part provided at a position corresponded to an end of both of the longer direction and the column direction, respectively. The plurality of brackets is fixed to the fixing part of the plurality of battery modules.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a battery pack mounted on a vehicle.

Background Art

[0002] Patent Document 1 discloses a battery unit mounting structure for suppressing vertical resonance between a vehicle body and a battery unit in an electric vehicle. The battery unit includes a battery module, a pair of side frames that have attachment portions to a pair of floor frames and extend in the front-rear direction, a battery tray that is supported by at least the pair of side frames and forms the bottom of the battery unit, and a plurality of cross frames that connect between the pair of side frames. Moreover, in order to give directivity to the movement of the so-called battery module, which separates the vertical movement of the battery tray supported by the side frames from the vertical movement of the battery module, the battery module is attached to the cross frame so as to be vertically displaceable with respect to the battery tray.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a vehicle equipped with a battery pack, increasing the natural frequency of the battery pack leads to an improvement in the ride comfort performance of the vehicle. In order to increase the natural frequency, it is effective to rigidly and continuously connect the battery modules housed in the battery pack case to the battery pack case. However, as a result, an input from the outside to the vehicle body is likely to be transmitted to the battery cells in the battery module.

[0005] This disclosure has been made in view of the above-mentioned issues, and aims to provide a battery pack that can increase the eigenvalue of the battery pack while making it difficult to transmit external input to the battery cells. [Means for solving the problem]

[0006] The battery pack according to this disclosure comprises a plurality of battery modules, a battery pack case, and a plurality of brackets. The plurality of battery modules are arranged in a row along the row direction. The battery pack case is attached to the vehicle body and houses the plurality of battery modules. The plurality of brackets secure the plurality of battery modules to the battery pack case. The row direction is perpendicular to the longitudinal direction of each of the plurality of battery modules. Each of the plurality of battery modules includes a fixing portion provided at a position corresponding to both the longitudinal direction and the row direction. The plurality of brackets are fixed to the fixing portions of the plurality of battery modules. [Effects of the Invention]

[0007] According to this disclosure, the bracket for fixing the battery module to the battery pack case is fixed to fixing parts provided at positions corresponding to both the longitudinal and column ends of the battery module. This structure makes it possible to increase the eigenvalue of the battery pack while making it difficult to transmit external input to the battery cells. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram schematically shows the configuration of a battery pack according to an embodiment. [Figure 2] Figure 1 is a perspective view illustrating the configuration of the bracket shown. [Modes for carrying out the invention]

[0009] 1. Battery pack configuration Figure 1 is a schematic diagram showing the configuration of the battery pack 1 according to an embodiment. The direction labeled "FR" in Figure 1 corresponds to the front direction of the vehicle on which the battery pack 1 is mounted. The direction labeled "RH" corresponds to the right direction of the vehicle. Figure 1 shows the internal structure of the battery pack 1 as viewed from above the vehicle (the direction labeled "UPR" in Figure 2).

[0010] The battery pack 1 comprises a plurality of battery modules 10 and a battery pack case (or simply a pack case) 20. Each of the plurality of battery modules 10 has a substantially rectangular parallelepiped shape and contains a plurality of battery cells stacked along the longitudinal direction D2 described later. The pack case 20 includes a lower case 21 and an upper case and houses the plurality of battery modules 10. In Figure 1 and Figure 2 described later, the upper case is not shown. The pack case 20 is attached to the vehicle body 100. For example, the pack case 20 includes a connecting portion 22 attached to the lower case 21. As an example, the lower case 21 is attached to the vehicle body 100 via the connecting portion 22 under the floor of the vehicle.

[0011] Inside the pack case 20, multiple battery modules 10 are arranged in a row along the row direction D1. As shown in Figure 1, when the battery pack 1 is viewed from above, the row direction D1 is perpendicular to the longitudinal direction D2 of each of the multiple battery modules 10. In this example, in each row of battery modules 10, two battery modules 10 are arranged connected along the longitudinal direction D2. Additionally, in this example, the row direction D1 is parallel to the vehicle's front-to-rear direction, and the longitudinal direction D2 is parallel to the vehicle's left-to-right direction (vehicle width direction).

[0012] The pack case 20 includes side reinforcements 23 and cross members 24 as structural components forming the skeleton of the pack case 20 (lower case 21). The side reinforcements 23 and cross members 24 are attached to the main body 25 of the lower case 21 so as to surround the multiple battery modules 10. More specifically, as shown in Figure 1, the side reinforcements 23 are positioned on the outside of each end of the battery module 10 in the longitudinal direction D2 (vehicle width direction) and extend along the row direction D1 (vehicle front-rear direction). The cross members 24 are positioned in the space between two adjacent battery modules 10 in the row direction D1 and extend along the longitudinal direction D2. Both ends of each cross member 24 are connected to two side reinforcements 23, respectively. The pack case 20 has a structure that distributes loads acting on the pack case 20 from the outside using the side reinforcements 23 and cross members 24 formed in this way.

[0013] Furthermore, the battery pack 1 includes multiple brackets 30 for securing multiple battery modules 10 to the pack case 20. The configuration of the brackets 30 will be described below with additional reference to Figure 2 in addition to Figure 1. Figure 2 is a perspective view illustrating the configuration of the brackets 30 shown in Figure 1. Figure 2 shows an enlarged view of the part indicated by the symbol A in Figure 1.

[0014] As shown in Figure 1, each of the multiple battery modules 10 has a fixing portion 11 that is connected to a bracket 30. The bracket 30 is fixed to the fixing portion 11 by fastening, for example, via fasteners 31 such as bolts (see Figure 2). In Figure 1, only one bracket 30 is illustrated as an example, but similar brackets are provided for the other fixing portions 11 as well.

[0015] The fixing portion 11 is provided at a position corresponding to the end of the battery module 10 in both the longitudinal direction D2 and the column direction D1. In the example shown in Figures 1 and 2, two fixing portions 11 are provided at one end of one battery module 10. More specifically, as an example, the two fixing portions 11 are formed on a member 13 that is separate from the case body 12 of the battery module 10 and attached to the case body 12. Note that one battery module 10 may have only one fixing portion.

[0016] More specifically, in the examples shown in Figures 1 and 2, when considering two battery modules (first and second battery modules) 10 adjacent to each other in the column direction D1, the bracket 30 is formed to be fixed to both the fixing portion 11 of the first battery module 10 and the fixing portion 11 of the second battery module 10 (except for brackets fixed to fixing portions 11 located at the ends of the battery pack 1 in the column direction D1). In other words, the bracket 30 is formed to straddle the first and second battery modules 10. More specifically, each bracket 30 is fixed to the fixing portion 11 of the first battery module 10 that is closer to the second battery module 10. Similarly, each bracket 30 is fixed to the fixing portion 11 of the second battery module 10 that is closer to the first battery module 10.

[0017] Furthermore, regarding each bracket 30 on the lower case 21, in the example shown in Figures 1 and 2, each bracket 30 is fixed to the side reinforcement 23 of the lower case 21. This fixing is also done, for example, by fastening via fasteners 32 such as bolts.

[0018] 2. Effects In vehicles equipped with battery packs, increasing the eigenvalue of the battery pack leads to an improvement in the vehicle's ride comfort performance (more specifically, a reduction in floor vibration levels due to mass effects). To increase this eigenvalue, it is effective to rigidly and continuously connect (fix) the battery module (high-rigidity member) housed in the battery pack case to the battery pack case. Specifically, it is effective to continuously (entirely) fix the end of the battery module in the longitudinal direction D2 along the column direction D1. In addition, as adopted in the example of battery pack 1 shown in Figure 1, fixing the battery module 10 to the side reinforcement 23, which is one of the members of the skeletal structure forming the skeleton of the lower case 21, via a bracket 30 is also effective in increasing the fixing value.

[0019] However, as mentioned above, if a configuration is adopted to increase the fixed value, external inputs to the vehicle body become more easily transmitted to the battery cells in the battery module. More specifically, in the example shown in Figure 1, inputs to the vehicle body 100 from the left or right direction (inputs during a side collision) become more easily transmitted to the battery cells in the battery module 10 via the bracket 30.

[0020] In view of the above problems, in the battery pack 1 according to the present embodiment, the fixing portion 11 for fixing each battery module 10 to the pack case 20 (lower case 21) via the bracket 30 is provided at a position corresponding to the end of the battery module 10 in both the longitudinal direction D2 and the column direction D1. In other words, in the battery pack 1, at the end of each battery module 10 in the longitudinal direction D2, at a portion other than the end in the column direction D1 (that is, the central portion of the ventral surface of the battery module 10, which is the weak portion B of the battery module 10 hatched in FIG. 2), the fixing portion 11 for fixing the bracket 30 is not provided. As a result, as shown by the arrow C in FIG. 2, an external input via the fastening point of the bracket 30 is transmitted to the structural member (such as the side wall 12a of the case body 12) of the battery module 10. Therefore, the internal components of the battery module 10, such as battery cells and connection parts, can be protected. In addition, the weak portion B here is a portion where, because it is separated from the structural member of the battery module 10 described above, when an external input acts, the input easily acts on the internal components such as battery cells.

[0021] As described above, according to the battery pack 1 according to the present embodiment, it is possible to increase the characteristic value of the battery pack 1 while making it difficult to transmit an external input to the battery cells.

[0022] In addition, in the present embodiment, each of the plurality of brackets 30 is formed so as to be fixed to both the fixing portion 11 of the first battery module 10, which is one of the two battery modules 10 adjacent to each other in the column direction D1, and the fixing portion 11 of the second battery module 10, which is the other. Thereby, compared with the comparative example in which the brackets 30 are individually set for the respective fixing portions 11 of the first and second battery modules 10, the number of parts and the assembly man-hours can be reduced, and the brackets 30 can be efficiently set. Also, depending on the way the external input acts, an effect of favorably dispersing the external input to the two battery modules 10 can be expected compared with the above comparative example.

[0023] In addition, in the present embodiment, the pack case 20 (lower case 21) includes a cross member 24 extending along the longitudinal direction D2 in the space between two battery modules 10 adjacent to each other in the column direction D1. By arranging the cross member 24 between the battery modules 10 in this way, the input transmitted to each fixing portion 11 from the outside via the bracket 30 can be effectively reduced by the cross member 24.

Description of reference numerals

[0024] 1 Battery pack, 10 Battery module, 11 Fixing portion, 20 Battery pack case, 24 Cross member, 30 Bracket, 100 Vehicle body

Claims

[Claim 1] Multiple battery modules arranged in a row along the direction of the column, A battery pack case that is attached to the vehicle body and houses the aforementioned multiple battery modules, Multiple brackets for fixing the multiple battery modules to the battery pack case, A battery pack equipped with, The aforementioned column direction is a direction perpendicular to the longitudinal direction of each of the plurality of battery modules, The battery pack case includes, as a component of the skeletal structure forming the framework of the battery pack case, a cross member that extends along the longitudinal direction in the space between two battery modules that are adjacent to each other in the row direction among the plurality of battery modules. Each of the plurality of battery modules includes a fixing portion provided at a position corresponding to both the longitudinal and columnar ends, The plurality of brackets are fixed to the fixing portion of the plurality of battery modules. The plurality of battery modules include first and second battery modules that are adjacent to each other in the row direction, The two fixing portions of the first battery module include the first fixing portion that is closer to the second battery module in the row direction, The two fixing portions of the second battery module include the second fixing portion that is closer to the first battery module in the row direction. At least one of the plurality of brackets is formed to cover the first and second fixing portions from above the battery pack together with the cross member located between the first and second fixing portions in the row direction, and is fixed to both the first and second fixing portions. A battery pack characterized by the following features.

Images