Battery pack

Abstract

To detect a road surface input by a sensor even in a protection structure that is hardly deformed when receiving a load due to road surface interference.SOLUTION: A battery pack includes: a lower case housing a battery cell; a protection structure arranged below the lower case; and a sensor for detecting a load inputted from the protection structure to the lower case. The protection structure has: a share panel forming the lowest layer; and an elastic body interposed between the share panel and the lower case. The elastic body is elastically deformed by a load from below, and causes the displacement of the share panel relative to the lower case. The sensor is arranged in the same layer as the elastic body between the lower case and the share panel and detects the load inputted to the lower case according to the displacement of the share panel caused by the electric deformation of the electric body.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Patent Document 1 discloses that a vehicle with a battery pack mounted on the floor of the vehicle compartment is provided with a structure for protecting the battery pack, which includes a plate-shaped underguard disposed below the battery pack case and a resin cover attached to the bottom of the underguard. In the configuration described in Patent Document 1, when an impact due to road interference is input to the resin cover, the resin cover first deforms to absorb the impact, and if the impact cannot be fully absorbed by the deformation of the cover, the plate-shaped underguard deforms to absorb the impact. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7216354 Summary of the Invention [Problem to be solved by the invention]

[0004] The configuration described in Patent Document 1 absorbs the load caused by road interference by significantly deforming the underguard, which serves as a protective structure for protecting the battery cells from road interference, but does not disperse the collision load using a protective structure that is less prone to deformation.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a battery pack that can detect road surface input using a sensor even if the protective structure is not easily deformed when subjected to a load due to road surface interference. [Means for solving the problem]

[0006] The present invention comprises a lower case that accommodates battery cells, a protective structure that is arranged below the lower case and protects the battery cells against loads from below, and a sensor that detects a load input from the protective structure to the lower case, wherein the protective structure has a share panel that forms the lowest layer, and an elastic body that is interposed between the share panel and the lower case, the elastic body elastically deforms due to the load from below, causing displacement of the share panel relative to the lower case, and the sensor is arranged in the same layer as the elastic body, between the lower case and the share panel, and detects the load input to the lower case in accordance with the displacement of the share panel when the elastic body elastically deforms. Effect of the Invention

[0007] In the present invention, the sensor can detect road surface input even in a protective structure that is not easily deformed when subjected to a load due to road surface interference. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating a battery pack according to an embodiment. [Diagram 2] FIG. 4 is a diagram for explaining characteristics of a sensor. [Diagram 3] FIG. 13 is a diagram illustrating a protective structure according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a battery pack according to an embodiment of the present invention will be specifically described, however, the present invention is not limited to the embodiment described below.

[0010] 1 is a diagram showing a battery pack according to an embodiment. The battery pack 1 is mounted on an electric vehicle and supplies power to a motor for driving the vehicle. The battery pack 1 is disposed below a floor panel of the electric vehicle.

[0011] The battery pack 1 includes a battery cell 2, a case 10, and a protective structure 20.

[0012] The case 10 houses a battery module made up of multiple battery cells 2. The multiple battery modules are housed inside the case 10. In an electric vehicle, the case 10 is disposed below a floor panel and fixed to the vehicle body. For example, the case 10 is fixed to a rocker or cross member via a fixing member such as a bracket.

[0013] The case 10 comprises an upper case 11 and a lower case 12. The upper case 11 is disposed above the battery cells 2 and is formed so as to cover the openings of the lower case 12. The lower case 12 is disposed below the battery cells 2 and is a case member on which the battery cells 2 are placed. The lower case 12 has an opening that opens upward and a bottom 12a on which the battery cells 2 are placed. The upper case 11 and the lower case 12 are integrated together by fastening members such as bolts. In the battery pack 1, multiple battery modules are housed in the internal space formed by the upper case 11 and the lower case 12. The case 10 is fixed by fastening a flange portion of the lower case 12 to a body such as a rocker of the electric vehicle.

[0014] The protective structure 20 is a structure for protecting the battery cells 2 from road interference. In an electric vehicle equipped with a battery pack 1, when the battery pack 1 is attached to the bottom of the vehicle body, road interference may occur in which a curb, obstacle, or the like collides with the bottom of the battery pack 1. When road interference occurs, a collision load is input to the battery pack 1 from below. To protect the battery cells 2 from this collision load, the protective structure 20 is arranged below the battery cells 2.

[0015] The protective structure 20 includes a shear panel 21, a reinforcing member 22, a pressing member 23, and an elastic member 24.

[0016] The protective structure 20 is not a structure that undergoes large deformation in which the shear panels 21 deform significantly to absorb the energy of road interference, but a structure that undergoes small deformation in which the lower structure receives the collision load and distributes the input to the battery cells 2. The protective structure 20 is a structure that does not easily deform.

[0017] The shear panel 21 is a member against which curbs, obstacles, and the like collide due to road surface interference, and is a member to which a collision load due to road surface interference is input. The shear panel 21 is disposed at the lowest part of the protective structure 20, and is formed in a flat plate shape so as to cover the entire bottom surface 12b of the lower case 12 from below. The shear panel 21 forms the lowest layer of the protective structure 20. In the protective structure 20, a collision load input to the shear panel 21 is transmitted from the shear panel 21 to the reinforcing member 22. The shear panel 21 is disposed below the reinforcing member 22, and is integrated with the reinforcing member 22. The shear panel 21 is attached to the lower part of the reinforcing member 22 by fastening members such as bolts and pins.

[0018] The reinforcing member 22 is a reinforcing panel that receives a collision load transmitted from the share panel 21. The reinforcing member 22 is formed so as to cover the entire bottom surface 12b of the lower case 12 from below. The reinforcing member 22 is integrated with a supporting member 26 by a bolt 25. The supporting member 26 is fixed to the vehicle body. The reinforcing member 22 has a flat plate portion 22a and a protruding portion 22b that is convex upward.

[0019] The flat portion 22a is formed to include the peripheral portion of the reinforcing member 22, and forms a portion to which the shear panel 21 is attached. The protruding portion 22b forms the center portion of the reinforcing member 22, and is formed in a shape that protrudes upward from the flat portion 22a. The flat portion 22a is formed around the protruding portion 22b. The protruding portion 22b is disposed below the portion where the battery cell 2 is placed. The protective structure 20 is configured so that a collision load input to the shear panel 21 is transmitted from the reinforcing member 22 to the pressing member 23. The reinforcing member 22 is disposed below the pressing member 23 and is integrated with the pressing member 23. The protruding portion 22b of the reinforcing member 22 is joined to the lower portion of the pressing member 23 by, for example, welding.

[0020] The pressing member 23 is a pressing panel that presses the elastic member 24 by the collision load transmitted from the reinforcing member 22. The pressing member 23 is disposed below the elastic member 24 and is in surface contact with the lower surface of the elastic member 24. The pressing member 23 has a flat plate portion 23a and a convex portion 23b that is convex upward.

[0021] The flat plate portion 23a is a portion attached to the protruding portion 22b of the reinforcing member 22. The pressing member 23 is integrated with the reinforcing member 22 in a state in which the lower surface of the flat plate portion 23a and the upper surface of the protruding portion 22b are in surface contact with each other. The protruding portion 23b is formed in a shape that protrudes upward from the flat plate portion 23a. The protruding portion 23b is disposed below the location where the elastic member 24 is provided and above the location where the protruding portion 22b of the reinforcing member 22 is provided. The protective structure 20 is configured so that a collision load input to the shear panel 21 is transmitted from the pressing member 23 to the elastic member 24. The upper surface of the protruding portion 23b of the pressing member 23 serves as a pressing surface, and the pressing member 23 presses the elastic member 24 upward by the collision load transmitted from the reinforcing member 22.

[0022] The elastic member 24 is an elastic body interposed between the shear panel 21 and the lower case 12, and is formed in a flat plate shape. The elastic member 24 is sandwiched between the convex portion 23b of the pressing member 23 and the bottom portion 12a of the lower case 12 while being in surface contact with the bottom surface 12b of the lower case 12. The elastic member 24 elastically deforms so as to be compressed upward when it receives a load from the pressing member 23. In the protective structure 20, a collision load input to the shear panel 21 is transmitted to the elastic member 24, whereby the elastic member 24 elastically deforms, causing a displacement of the shear panel 21 required for the sensor 30 to detect the load.

[0023] Moreover, the protective structure 20 is provided with a plurality of elastic members 24 and pressing members 23. The plurality of elastic members 24 are in surface contact with the bottom surface 12b of the lower case 12. Pressing members 23 are provided at positions corresponding to the plurality of elastic members 24. Of the transmission path of the load applied to the elastic members 24 due to input from the share panel 21, a reinforcing member 22 is provided on the transmission path from the share panel 21 to the pressing member 23. The reinforcing member 22 distributes the collision load and transmits the load to the plurality of pressing members 23. The protective structure 20 receives the collision load, thereby dispersing the collision load input to the bottom 12a of the lower case 12. The protective structure 20 can distribute the input to the lower parts of the battery cells 2.

[0024] Furthermore, a switch-type sensor 30 that detects a load is provided below the lower case 12. The battery pack 1 is configured to include the sensor 30. The battery pack 1 has a protective structure 20 and the sensor 30 as a lower structure.

[0025] The sensor 30 is configured to detect a load according to the amount of deformation of the elastic member 24. The sensor 30 detects a load input from the protective structure 20 to the lower case 12. The sensor 30 is disposed between the bottom surface 12b of the lower case 12 and the upper surface of the flat plate portion 23a of the pressing member 23, and is attached to the bottom surface 12b in a state spaced apart from the flat plate portion 23a.

[0026] The sensor 30 is disposed between the lower case 12 and the shear panel 21 in the same layer as the elastic member 24. The sensor 30 detects the load according to the displacement of the protective structure 20 when the elastic member 24 elastically deforms. The protective structure 20 is a structure in which the shear panel 21, the reinforcing member 22, and the pressing member 23 are integrated, and is structured to be resistant to deformation due to road surface input and to disperse the load. The displacement of the protective structure 20 refers to the displacement of the shear panel 21, the reinforcing member 22, and the pressing member 23 as one body. In other words, the displacement of the protective structure 20 can be said to be the displacement of the shear panel 21 relative to the lower case 12. When the elastic member 24 elastically deforms so as to compress upward, the position of the pressing member 23 is displaced so that the distance between the bottom surface 12b of the lower case 12 and the upper surface of the flat plate portion 23a becomes narrower. The elastic member 24 elastically deforms due to the load from below caused by the road surface input, causing the shear panel 21 to be displaced relative to the lower case 12. Then, the amount of upward deformation of elastic member 24 increases, and flat plate portion 23a of pressing member 23 comes into contact with sensor 30, causing sensor 30 to detect the load. Sensor 30 is set to have the displacement and load characteristics shown in FIG.

[0027] As shown in FIG. 2, the sensor 30 varies in the detected load depending on the characteristics of the displacement and load in the elastic member 24 and the variation in the sensor mounting height and the reaction position. When the sensor 30 detects a load within a predetermined range, the elastic member 24 elastically deforms to absorb the collision load. In consideration of the variation in the detected load, the sensor 30 is set to always detect a load included in the load range A1 where detection is essential, and to always not detect a load included in the normal load range A2. The load range A1 where detection is essential is a load range equal to or greater than the load W1. The normal load range A2 is a load range equal to or less than the load W2. The load W1 is greater than the load W2. The variation in the detected load is included in a range greater than the load W2 and smaller than the load W1. In other words, the sensor 30 is configured to always detect the load W1, which is the lower limit of the load range A1 where detection is essential, and to always not detect the load W2, which is the upper limit of the normal load range A2.

[0028] In addition, as shown in FIG. 2, in the battery pack 1, it is assumed that the load range A1 that requires detection will be expanded due to changes in the resistance of the battery cells 2. In addition, it is assumed that the normal load range A2 will be narrowed due to changes in the normal input of the battery pack 1. In this case, the lower limit of the load range A1 that requires detection will be load W3. The load W3 is smaller than the load W1. Furthermore, the upper limit of the normal load range A2 will be load W4. The load W4 is smaller than the load W2. As a result, the detection conditions change, so the sensing performance of the sensor 30 is adjusted. The characteristics of the displacement and load in the elastic member 24 and the mounting height of the sensor 30 are adjusted. Through this adjustment, the sensing performance is adjusted so that the sensor 30 detects loads that are equal to or smaller than the allowable input of the battery cells 2, and does not detect loads that can guarantee functionality. The sensor 30 after adjustment is configured to always detect the load W3, which is the lower limit of the load range A1 that requires detection, and always not detect the load W4, which is the upper limit of the normal load range A2.

[0029] As described above, according to the embodiment, the sensor 30 can be configured to appropriately detect a load for the protective structure 20, which receives a load on the lower structure of the battery pack 1 and distributes the input to the battery cells 2 and has little deformation.

[0030] Moreover, the battery pack 1 of the modified example includes a protective structure 40 disposed below the lower case 12. The protective structure 40 includes a share panel 41, a lower panel 42, a spring 43, and an upper panel 44.

[0031] The shear panel 41 forms the bottom layer of the protective structure 40. The lower panel 42 is a flat reinforcing panel, and is attached to the upper surface of the shear panel 41. The lower panel 42 is integrated with the shear panel 41. The upper panel 44 is a flat reinforcing panel, and is disposed between the lower panel 42 and the lower case 12. The upper panel 44 is attached to the bottom surface 12b of the lower case 12. The shear panel 41, the lower panel 42, and the upper panel 44 are constructed from materials and structures that are difficult to deform.

[0032] The spring 43 is a spring-like member that expands and contracts in the vertical direction, and is disposed so as to connect the lower panel 42 and the upper panel 44. The spring 43 is an elastic body interposed between the shear panel 41 and the lower case 12. The spring 43 undergoes compressive deformation (elastic deformation) in the vertical direction, thereby generating a displacement of the shear panel 21 required for the sensor 30 to detect the load.

[0033] A sensor 50 for detecting a load is provided between the lower panel 42 and the upper panel 44. In this modification, the sensor 50 is built into the protective structure 40.

[0034] Sensor 50 is configured to detect a load according to the amount of deformation of spring 43. Sensor 50 detects a load input from the protective structure 40 to lower case 12. Sensor 50 is disposed between the lower surface of upper panel 44 and the upper surface of lower panel 42, and is attached to the lower surface of upper panel 44 in a state spaced apart from the upper surface of lower panel 42.

[0035] The sensor 50 is disposed between the lower case 12 and the share panel 41 in the same layer as the spring 43. The sensor 50 detects the load in response to the displacement of the protective structure 40 when the spring 43 elastically deforms. When the spring 43 elastically deforms so as to be compressed in the vertical direction, the position of the lower panel 42 is displaced so that the distance between the lower surface of the upper panel 44 and the upper surface of the lower panel 42 becomes narrower. Then, the amount of compression of the spring 43 increases, and the lower panel 42 comes into contact with the sensor 50, whereby the sensor 50 detects the load. The sensor 50 can be set to have the displacement and load characteristics as shown in FIG. 2. [Explanation of symbols]

[0036] 1 Battery pack 2 Battery Cells 10 Cases 11 Upper Case 12 Lower case 20 Protective structure 21 Share Panel 24 Elastic member 30 Sensors

Claims

1. A lower case that houses the battery cells; a protective structure disposed below the lower case for protecting the battery cells from a load applied from below; a sensor for detecting a load input from the protective structure to the lower case; Equipped with The protective structure comprises: The share panel that forms the bottom layer; an elastic body interposed between the share panel and the lower case, the elastic body is elastically deformed by the load from below, causing displacement of the shear panel relative to the lower case, The sensor is disposed between the lower case and the share panel in the same layer as the elastic body, and detects a load input to the lower case in response to a displacement of the share panel when the elastic body elastically deforms. A battery pack characterized by:

2. the elastic body is a flat elastic member that is in surface contact with a bottom surface of the lower case, The protective structure comprises: a pressure panel that is in surface contact with a lower surface of the elastic member and presses the elastic member upward; A reinforcing panel is interposed between the share panel and the pressing panel, The elastic member is provided in a plurality of positions on the bottom surface of the lower case, The pressure panel is provided at a position corresponding to the elastic member, The reinforcing panel is provided on a transmission path from the shear panel to the pressing panel of a load applied to the elastic member by input from the shear panel, and distributes the load and transmits it to the pressing panel.

2. The battery pack according to claim 1 .

3. The protective structure comprises: a lower panel integral with the share panel; an upper panel disposed between the lower panel and the lower case, The elastic body is a spring-like member and is disposed so as to connect the lower panel and the upper panel.

2. The battery pack according to claim 1 .

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