Battery device and industrial vehicle equipped with battery device

Abstract

To provide a highly versatile battery device and an industrial vehicle equipped with a battery device that can be applied to the compartments of various types of industrial vehicles.SOLUTION: In a battery device 50 that can be housed in a battery compartment provided in the body of an industrial vehicle, the battery device 50 includes a secondary battery and a battery case provided with a case body 54 that houses the secondary battery, and a weight portion that adjusts the weight of the battery case, the secondary battery is a high-density energy secondary battery of a non-lead battery type, the battery case is smaller in size than the battery compartment, and a case box 52 that can house the battery case and has a shape that fits the battery compartment is provided, and the weight portion is provided at least on the bottom and sides of the case box 52.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a battery device and an industrial vehicle equipped with a battery device. [Background technology]

[0002] Some forklifts used as industrial vehicles are equipped with a battery case for a lead-acid battery (hereinafter referred to as a "lead battery case") as a power source. A compartment for accommodating the lead battery case is formed in the body of this type of forklift. In recent years, lithium-ion secondary batteries, which have high output and high energy density, have been put to practical use as a power source for forklifts used as industrial vehicles. Furthermore, battery cases for lithium-ion secondary batteries (hereinafter referred to as a "lithium battery case"), which have roughly the same charge / discharge capacity as lead batteries, are smaller and lighter than lead battery cases.

[0003] When a lithium battery case is mounted on the body of a forklift truck on which a lead battery case is mounted, the weight of the lithium battery case must be approximately the same as the weight of the lead battery case due to the weight balance required for the body.

[0004] For example, the secondary battery device for a forklift disclosed in Patent Document 1 has a box-shaped case and multiple battery modules, each having multiple unit cells housed in the case and connected to each other. The secondary battery device also includes a battery stack assembly formed by stacking multiple battery rows, each of which has multiple battery modules arranged in a line, and a weight attached to the bottom of the battery stack assembly.

[0005] Another known prior art is an industrial vehicle for transporting goods, as disclosed in Patent Document 2. The industrial vehicle for transporting goods disclosed in Patent Document 2 is a forklift equipped with a counterweight and multiple batteries housed in a housing section provided on the vehicle body. The counterweight is a case that prevents the multiple batteries from moving within the housing section when the multiple batteries are housed in the housing section. This case is configured to function as a counterweight. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-54353 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-239261 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the forklift secondary battery device disclosed in Patent Document 1 merely discloses providing a weight at the bottom of the battery case. Also, the forklift disclosed in Patent Document 2 requires that the case be manufactured to fit the compartment of each forklift model, which poses a problem that the number of case types increases as the number of model types increases.

[0008] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a highly versatile battery device that can be applied to compartments of various types of industrial vehicles, and an industrial vehicle equipped with a battery device. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a battery device that can be housed in a battery compartment provided in the body of an industrial vehicle, the battery device having a secondary battery and a battery case provided with a case body that houses the secondary battery, and a weight portion that adjusts the weight of the battery case, the secondary battery being a non-lead battery type high-density energy secondary battery, the battery case having dimensions smaller than the dimensions of the battery compartment, a case box that can house the battery case and has a shape that fits the battery compartment, and the weight portion being provided on at least the bottom and sides of the case box.

[0010] In the present invention, the battery case is smaller than the battery compartment provided in the vehicle body. The case box is capable of accommodating the battery case and has a shape that fits the battery compartment. The weight portion is provided at least on the bottom and side portions of the case box. Therefore, even if the battery case is smaller than the dimensions of the battery compartment and does not fit, the battery case can be mounted on the vehicle body by being housed in a case box shaped to fit the battery compartment. Furthermore, the weight portion ensures the weight required for the battery device. In other words, by preparing a common battery case that can be used for multiple vehicle types and case boxes tailored to each vehicle type, a highly versatile battery device that can be used in the battery compartments of many types of industrial vehicles can be provided.

[0011] In the above battery device, the weight of the case box may be adjusted based on the height of the upper edge of the side portion on which the weight portion is provided. In this case, increasing the height of the upper edge of the case box on which the weight portion is provided increases the weight of the case box, whereas decreasing the height of the upper edge of the case box on which the weight portion is provided decreases the weight of the case box. In other words, the weight of the battery device can be adjusted based on the height of the upper edge of the case box on which the weight portion is provided.

[0012] In the above battery device, the case box may be provided with a fastener for hanging. In this case, the case box is provided with a locking device for hanging, so that the case box can be hung with the battery case housed in it, making it easy to attach and detach the battery device to and from the battery compartment of the vehicle body.

[0013] In the above battery device, the secondary battery may be a lithium-ion secondary battery. In this case, the secondary battery is a lithium-ion secondary battery, which can achieve a higher energy density than a lead battery. This allows the battery case to be made lighter and smaller, making it easier to realize a common battery case that can be applied to multiple vehicle models.

[0014] The present invention also provides an industrial vehicle having a vehicle body and a battery device that can be housed in a battery compartment provided in the vehicle body, wherein the battery device is the battery device described above. In the present invention, even if the battery case is smaller than the battery compartment and does not fit, it can be mounted on the vehicle by storing the battery case in a case box of a shape that fits the battery compartment. In addition, the weight required for the battery device can be ensured by the weight section. [Effects of the Invention]

[0015] The present invention can provide a highly versatile battery device that can be applied to compartments of various types of industrial vehicles, and an industrial vehicle equipped with the battery device. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing an overview of a forklift according to a first embodiment. [Figure 2] 1 is a plan view showing an outline of a forklift according to a first embodiment. [Figure 3]FIG. 2 is a plan view schematically showing a battery compartment of the forklift. [Figure 4] FIG. 1 is a perspective view of a lead battery case that can be mounted on a forklift. [Figure 5] 1 is a perspective view of a battery device according to a first embodiment. [Figure 6] 1 is an exploded perspective view of a battery device according to a first embodiment. [Figure 7] FIG. 10 is an exploded perspective view of a battery device according to a second embodiment. [Figure 8] FIG. 11 is an exploded perspective view of a battery device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] (First embodiment) A battery device and an industrial vehicle equipped with the battery device according to a first embodiment will be described below with reference to the drawings. The industrial vehicle of this embodiment is a forklift, which is a counterweight-type battery-powered forklift. Note that the terms "front / back," "left / right," and "up / down" that specify directions are based on the state in which the forklift operator is seated in the driver's seat and facing the forward direction of the forklift.

[0018] First, the forklift will be described. As shown in Figure 1, a forklift 10 has front wheels 12 at the front of a body 11 and rear wheels 13 at the rear of the body 11. The front wheels 12 are drive wheels and the rear wheels 13 are steered wheels. A traction motor 14 that drives the front wheels 12 is mounted on the body 11. A counterweight 15 is provided at the rear of the body 11. The counterweight 15 is used to adjust the vehicle weight and balance the weight of the body 11. A loading device 16 is provided at the front of the body 11.

[0019] The cargo handling apparatus 16 includes a mast 17 having an outer mast 18 and an inner mast 19. As shown in Figure 2, the cargo handling apparatus 16 includes a lift bracket 20 that can be raised and lowered along the inner mast 19. A pair of forks 21, one on the left and one on the right, are secured to the lift bracket 20.

[0020] A tilt cylinder 22, which is operated by supplying and discharging hydraulic oil, is installed between the vehicle body 11 and the cargo handling device 16. Operation of the tilt cylinder 22 causes the cargo handling device 16 to tilt in the front-to-rear direction with the lower end of the cargo handling device 16 as a fulcrum (the center of the axle of the front wheels 12). The outer mast 18 is provided with a lift cylinder 23, which is operated by supplying and discharging hydraulic oil (see Figure 1). Operation of the lift cylinder 23 causes the inner mast 19 to rise and fall inside the outer mast 18, and also causes the lift bracket 20 to rise and fall.

[0021] A driver's seat 24 is provided near the center of the vehicle body 11. A head guard 25 that covers the upper part of the driver's seat 24 is provided on the vehicle body 11. An instrument panel 26 is provided in front of the driver's seat 24. A steering column 27 that supports a steering wheel 28 is provided on the instrument panel 26. As shown in FIG. 2, the instrument panel 26 is provided with a lift lever 29 and a tilt lever 30 as loading / unloading levers. The lift lever 29 is an operating lever for raising and lowering the lift bracket 20 and the fork 21. The tilt lever 30 is an operating lever for tilting the mast 17 forward and backward.

[0022] An openable and closable seat stand 31 is provided in front of the counterweight 15 in the driver's seat 24. A driver's seat 32 is provided above the seat stand 31. A removable or openable toe board 33 is provided on the floor of the driver's seat 24. A battery compartment 35 is provided in the vehicle body 11 below the seat stand 31 and the toe board 33.

[0023] The battery compartment 35 is a space partitioned by multiple plate members provided on the vehicle body 11 and can accommodate a lead-acid battery case 40 or a battery device 50 (described below). As shown in FIG. 3 , the plate members include a front plate 36, a rear plate 37, and a pair of left and right inner plates 38. The lead-acid battery case 40 or the battery device 50 is mounted on a bottom 39 of the battery compartment 35. As shown in FIG. 4 , the lead-acid battery case 40 includes multiple rechargeable lead-acid batteries 41 and a box-shaped case body 42 that accommodates the multiple lead-acid batteries 41. When housed in the battery compartment 35, the lead-acid battery case 40 is restricted by the front plate 36, the rear plate 37, and the inner plates 38, and hardly shifts forward, backward, left, or right. In other words, the battery compartment 35 is partitioned to fit the dimensions of the lead-acid battery case 40. When replacing the lead-acid battery case 40, the lead-acid battery case 40 can be inserted or removed from the battery compartment 35 by opening the toe board 33 together with the seat stand 31.

[0024] Next, the battery device 50 of this embodiment will be described. As shown in Fig. 5, the battery device 50 includes a lithium battery case 51 as a battery case, and a case box 52 capable of accommodating the lithium battery case 51 and having a weight function. The battery device 50 is manufactured with dimensions that fit into the battery compartment 35 of the forklift 10 so that it can be accommodated in the battery compartment 35.

[0025] The lithium battery case 51 includes a plurality of lithium ion secondary batteries 53 as secondary batteries and a box-shaped case body 54 that houses the plurality of lithium ion secondary batteries 53. The lithium ion secondary batteries 53 are non-lead battery-type high-density energy secondary batteries. The case body 54 is formed from a steel plate. Although not shown, the lithium battery case 51 also includes a battery control unit that controls the charging and discharging of the lithium ion secondary batteries 53, a monitoring unit that monitors the status of the lithium ion secondary batteries 53, and connection cables. The lithium battery case 51 can be installed in different types of forklifts by replacing the case box 52 with a different type of case box.

[0026] The lithium battery case 51 is substantially rectangular, but is smaller than the lead battery case 40 because the lithium-ion secondary battery 53 is a non-lead battery-based high-density energy secondary battery. The weight of the lithium battery case 51 is also lighter than the lead battery case 40. Therefore, in this embodiment, the case box 52 has a shape that fits into the battery compartment 35 so that the battery device 50 can be housed in the battery compartment 35. Furthermore, the case box 52 has a weighting function, which makes the weight of the battery device 50 approximately equal to the weight of the lead battery case 40, ensuring the weight balance of the vehicle body 11 required when the battery device 50 is installed.

[0027] Next, the case box 52 will be described in detail. As shown in FIG. 6 , the case box 52 is formed into a box shape using steel plates and has a bottom wall 55, a front wall 56, a rear wall 57, and a pair of left and right side walls 58. The bottom wall 55 forms the bottom of the case box 52, and the front wall 56, rear wall 57, and the pair of left and right side walls 58 form the sides of the case box 52. The bottom wall 55, the front wall 56, rear wall 57, and the pair of left and right side walls 58 are formed from steel plates. A pair of left and right bottom weights 59 are provided on the upper surface of the bottom wall 55. The bottom weights 59 correspond to weight portions for adjusting the weight of the battery device 50 and are elongated steel plates that are thicker than the steel plates that form the front wall 56 and rear wall 57. The bottom weights 59 are welded to the bottom wall 55 so that their longitudinal direction is the front-to-rear direction. The pair of bottom weights 59 have flat upper surfaces that serve as seats on which the lithium battery case 51 is placed, and are at the same height. The weights of the pair of bottom weights 59 are approximately the same for left and right weight balance.

[0028] The pair of side walls 58 are each formed of a steel plate thicker than the steel plate forming the front wall 56 and the rear wall 57, and correspond to weight portions for adjusting the weight of the battery device 50. In other words, it can be said that weight portions are provided on the sides of the case box 52. The thickness of the side walls 58, which are formed of steel plate, is a thickness specified by steel plate standards, taking into account the weight required for the battery device 50. The height of the upper edges of the side walls 58 is set according to the weight required for the battery device 50. In other words, the weight of the case box 52 is adjusted based on the height of the upper edges of the side walls 58. In this embodiment, the pair of side walls 58 are set higher than the front wall 56 and the rear wall 57. The weights of the pair of side walls 58 are approximately the same for left and right weight balance. The dimensions of the case box 52 are set to fit into the battery compartment 35. In other words, the outer dimensions of the case box 52 are the same as or approximately the same as the outer dimensions of the lead-acid battery case 40. The inner dimensions of the case box 52 are slightly larger than the outer dimensions of the lithium battery case 51.

[0029] In this embodiment, a pair of locking devices 60 are provided on the upper part of the side wall portion 58. The locking devices 60 include a base portion 61 welded to the upper surface of the side wall portion 58, and a generally trapezoidal locking portion 62 extending upward from the base portion 61 and having a through hole 63. By passing a hanging device such as a wire or a hook through the through hole 63 of the locking devices 60, it becomes possible to hang the case box 52 with the lithium battery case 51 inserted therein. The case box 52 is equipped with a jump-out prevention mechanism (not shown) to prevent the lithium battery case 51 from jumping out of the case box 52 when the forklift 10 tips over.

[0030] Next, the operation of the battery device 50 of this embodiment will be described. The battery compartment 35 of the forklift 10 is a space for accommodating the lead battery case 40. In this embodiment, the battery device 50 can be accommodated in the battery compartment 35 by accommodating the lithium battery case 51 in a case box 52 that fits into the battery compartment 35. The battery device 50 requires a weight equivalent to the weight of the lead battery case 40 for the weight balance of the vehicle body 11, but the weight portions on the side walls 58 and the bottom weight 59 of the case box 52 adjust and ensure the necessary weight.

[0031] When replacing the battery device 50, the battery device 50 can be hung by passing a hanging tool such as a wire or hook through the through-hole 63 of the fastener 60 provided in the case box 52. Hanging is possible whether the lithium battery case 51 is housed in the case box 52 or not. The lithium battery case 51 fits into the case box 52, and no special means for fastening them together is provided, but there is almost no rattle between the lithium battery case 51 and the case box 52.

[0032] By mounting the battery device 50 in the battery compartment 35, the forklift 10 can travel using the lithium battery case 51 as a power source. To charge the lithium ion secondary battery 53 in the lithium battery case 51, the seat stand 31 and the toe board 33 are opened, the battery device 50 is removed by hanging it from the battery compartment 35, and it is then carried to a charging position. Alternatively, the lithium ion secondary battery 53 may be charged without removing the battery device 50 from the battery compartment 35.

[0033] The battery device 50 and the forklift 10 of this embodiment have the following advantages. (1) The lithium battery case 51 is smaller than the battery compartment 35 provided in the vehicle body 11. The case box 52 is shaped to accommodate the lithium battery case 51 and fit within the battery compartment 35. The weight portion is provided at least on the side wall portion 58 of the case box 52. Therefore, even if a small-sized lithium battery case 51 does not fit within the battery compartment 35, the lithium battery case 51 can be mounted on the vehicle body 11 by being housed in a case box shaped to fit within the battery compartment 35. Furthermore, the weight required for the battery device 50 can be ensured by the side wall portion 58 and the bottom weight 59. In other words, by providing a standardized lithium battery case 51 that can be used with multiple vehicle types and case boxes tailored to the vehicle type in addition to the case box 52, a highly versatile battery device that can be used in the battery compartments of many types of industrial vehicles can be provided.

[0034] (2) Increasing the height of the upper edge of the side wall 58 of the case box 52, on which the weight portion is provided, increases the weight of the case box 52. Decreasing the height of the upper edge of the side wall 58 of the case box 52 decreases the weight of the case box 52. In other words, the weight of the battery device 50 can be adjusted based on the height of the upper edge of the side wall 58 of the case box 52, on which the weight portion is provided.

[0035] (3) The case box 52 is provided with the fasteners 60 for hanging, so that the case box 52 can be hung with the lithium battery case 51 housed in the case box 52. This makes it easy to attach and detach the battery device 50 to and from the battery compartment 35 of the vehicle body 11.

[0036] (4) The secondary battery is a lithium-ion secondary battery 53, which can realize a secondary battery with higher energy density than the lead-acid battery 41. This allows the lithium battery case 51 to be made lighter and smaller, making it easier to realize a common lithium battery case 51 that can be applied to multiple vehicle models.

[0037] (Second embodiment) Next, a battery device and a forklift according to a second embodiment will be described. In this embodiment, the configuration of the case box is different from that of the first embodiment. In this embodiment, the same configuration as in the first embodiment will be referred to and the same reference numerals will be used.

[0038] 7, the battery device 71 includes a lithium battery case 51 as a battery case, and a case box 72 capable of housing the lithium battery case 51 and having a weight function. The battery device 71 is manufactured with dimensions that fit into a battery compartment (not shown) of a forklift (not shown) that is a different model from the forklift 10 so that it can be housed therein. The battery compartment of this embodiment is smaller in size than the battery compartment 35 of the first embodiment, and also has a different shape.

[0039] The case box 72 is formed into a box shape from steel plates and has a bottom wall 75, a front wall 76, a rear wall 77, and a pair of left and right side walls 78. The bottom wall 75 forms the bottom of the case box 72, and the front wall 76, rear wall 77, and the pair of left and right side walls 78 form the sides of the case box 72. The bottom wall 75, the front wall 76, rear wall 77, and the pair of left and right side walls 78 are formed from steel plates. A pair of left and right bottom weights 79 are provided on the upper surface of the bottom wall 75. The bottom weights 79 correspond to weight portions for adjusting the weight of the battery device 71 and are elongated steel plates that are thicker than the steel plates that form the pair of left and right side walls 78. The bottom weights 79 are welded to the bottom wall 75 so that their longitudinal direction is the front-to-rear direction. The pair of bottom weights 79 have flat upper surfaces that serve as seats on which the lithium battery case 51 is placed, and are at the same height. The weights of the pair of bottom weights 79 are approximately the same for left and right weight balance.

[0040] The front wall 76 and the rear wall 77 are each formed of a steel plate thicker than the steel plate forming the pair of left and right side walls 78, and correspond to weight portions for adjusting the weight of the battery device 71. In other words, it can be said that weight portions are provided on the sides of the case box 72. The thicknesses of the front wall 76 and the rear wall 77, which are formed of steel plate, are determined by steel plate standards in consideration of the weight required for the battery device 50. The heights of the upper edges of the front wall 76 and the rear wall 77 are set to match the weight required for the battery device 71. In other words, the weight of the case box 72 is adjusted based on the heights of the upper edges of the front wall 76 and the rear wall 77. In this embodiment, the front wall 76 and the rear wall 77 are basically set higher than the pair of side walls 78. The weights of the front wall 76 and the rear wall 77 are approximately the same to achieve a front-to-rear weight balance. Although not shown, a pair of locking devices 60 are provided on the upper parts of the front wall 76 and the rear wall 77.

[0041] In this embodiment, the lithium battery case 51 can be housed in a case box 72 that is shaped to fit the battery compartment, making it possible to mount the battery case 51 on a forklift. The weight required for the battery device 71 can be ensured by the front wall 76, rear wall 77, and bottom weight 79.

[0042] (Third embodiment) Next, a battery device and a forklift according to a third embodiment will be described. In this embodiment, the configuration of the case box is different from that of the first embodiment. In this embodiment, the same configuration as in the first embodiment will be referred to and the same reference numerals will be used.

[0043] 8, the battery device 81 includes a lithium battery case 51 as a battery case, and a case box 82 that can house the lithium battery case 51 and has a weight function. The battery device 81 is manufactured with dimensions that fit into a battery compartment (not shown) of a forklift (not shown) that is a different model from the forklift 10 so that it can be housed therein. Incidentally, the battery compartment of this embodiment is larger in size than the battery compartment 35 of the first embodiment and the battery compartment of the second embodiment, and also has a different shape.

[0044] The case box 82 is formed into a box shape from steel plates and has a bottom wall 85, a front wall 86, a rear wall 87, and a pair of left and right side walls 88. The bottom wall 85 forms the bottom of the case box 82, and the front wall 86, rear wall 87, and the pair of left and right side walls 88 form the sides of the case box 72. The bottom wall 85, the front wall 86, and the rear wall 87 are formed from steel plates. A pair of left and right bottom weights 89 are provided on the upper surface of the bottom wall 85. The bottom weights 89 correspond to weight portions for adjusting the weight of the battery device 81 and are elongated steel plates that are thicker than the steel plates that form the bottom wall 85, the front wall 86, the rear wall 87, and the pair of left and right side walls 88. The bottom weights 89 are welded to the bottom wall 85 so that their longitudinal direction is the front-to-rear direction. The pair of bottom weights 79 have flat upper surfaces that serve as seats on which the lithium battery case 51 is placed, and are at the same height. The weights of the pair of bottom weights 79 are approximately the same for left and right weight balance. Note that only one of the bottom weights 79 is shown in Figure 8.

[0045] The front wall 86 and the rear wall 87 are each formed from a steel plate. A pair of inner walls 90, 91 are erected on the bottom wall 85 between the front wall 86 and the rear wall 87. The inner wall 90 is formed from a steel plate that is thicker than the steel plate that constitutes the case box 72, and is provided approximately parallel to the front wall 86 with a gap therebetween. A rectangular column-shaped front weight 92 is provided between the front wall 86 and the inner wall 90. The front weight 92 is a steel plate that is thicker than the inner walls 90, 91, and is welded to the front wall 86, the front weight 92, and the bottom wall 85. The inner wall 90 and the front weight 92 function as weight portions provided on the front wall 86.

[0046] The inner wall portion 91 is formed of a steel plate that is thicker than the steel plate that constitutes the case box 72, and is disposed approximately parallel to the rear wall portion 87 with a gap therebetween. A rectangular pillar-shaped rear weight 93 is disposed between the rear wall portion 87 and the inner wall portion 91. The rear weight 93 is a steel plate that is thicker than the inner wall portions 90 and 91, and is welded to the rear wall portion 87, the rear weight 93, and the bottom wall portion 85. The inner wall portion 91 and the rear weight 93 function as weight portions disposed on the rear wall portion 87. The inner wall portions 90 and 91 have approximately the same weight to ensure a front-to-rear weight balance. The rear weight 93 also has approximately the same weight as the front weight 92 to ensure a front-to-rear weight balance.

[0047] The front-to-rear spacing between the inner walls 90, 91 is set to fit the size of the lithium battery case 51. The pair of side walls 88 are each provided with a spacing adjustment plate 94 that sets the spacing in the left-to-right direction to fit the size of the lithium battery case 51. The inner walls 90, 91 and the pair of spacing adjustment plates 94 regulate the front-to-rear and left-to-right positional deviation of the lithium battery case 51 housed in the case box 82 relative to the case box 82. In other words, the inner walls 90, 91 and the spacing adjustment plate 94 function as members for regulating positional deviation of the lithium battery case 51 within the case box 82.

[0048] In this embodiment, a pair of locking devices 95 are provided on the upper portions of the pair of side wall portions 88. The locking devices 95 are formed in a shape that allows a hanging device such as a wire or a hook to be locked. Specifically, the locking devices 95 are plate members with through holes that extend toward the inside of the case box 82 and are welded to the inner surfaces of the side wall portions 88. Therefore, the case box 52 with the lithium battery case 51 inserted therein can be hung by a hanging device.

[0049] In this embodiment, the lithium battery case 51 can be mounted on a forklift by being housed in a case box 82 that is shaped to fit the battery compartment. In particular, even if the battery compartment of the forklift is sufficiently large for the lithium battery case 51, the provision of inner walls 90, 91 and a gap adjustment plate 94 allows the lithium battery case 51 to be properly housed in the case box 82. Furthermore, the inner walls 90, 91, front weight 92, and rear weight 93 ensure that the battery device 81 has the necessary weight.

[0050] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the invention. For example, the following modifications may be made.

[0051] In the first and second embodiments, the weight of the case box is adjusted based on the height of the upper edge of the side portion on which the weight portion is provided. However, this is not limiting. For example, the weight of the case box may be adjusted by changing the thickness of the weight portion. Alternatively, the weight portion may be a combination of multiple weight pieces, and the weight of the case box may be adjusted by increasing or decreasing the number of weight pieces. In the above embodiment, the case box is provided with a locking device for hanging, but this is not limited to this. For example, if the battery device can be supported by a fork, a locking device is not required. Note that although the locking device is provided only on the case box, a locking device may also be provided on the battery case. In the above embodiment, a lithium ion secondary battery is used as an example of a non-lead battery-based high-density energy secondary battery, but the secondary battery is not limited to this. Any secondary battery having a higher energy density than a lead-acid battery may be used. In the above embodiment, the battery case is individually adapted to fit the battery compartment of each vehicle model, but by providing a battery case for each vehicle model and a common battery case that can be accommodated in the battery case, a battery device that can be installed in a plurality of vehicle models can be configured. In other words, a single battery case can be shared, improving the versatility of the battery case. In the above embodiment, the battery case and the battery box are mounted on the industrial vehicle as a single unit. However, this is not limited to this. For example, the battery case may be housed in the battery box after the battery box is mounted on the industrial vehicle. Furthermore, the battery case may be removed from the battery device mounted on the industrial vehicle first, and then the battery box may be removed from the industrial vehicle. In the above embodiment, a counterweight-type battery-powered forklift truck is described as an example of an industrial vehicle, but the present invention is not limited to this. The industrial vehicle may be, for example, a reach-type battery-powered forklift truck. Furthermore, the industrial vehicle may be, for example, an electric industrial vehicle other than a forklift truck, such as a golf cart. [Explanation of symbols]

[0052] 10. Forklift 11 Body 16 Cargo handling equipment 17 Mast 21 Fork 24 Driver's seat 35 Battery Compartment 40 Lead-acid battery case 50, 71, 81 Battery equipment 51 Lithium battery case 52, 72, 82 case boxes 53 Lithium-ion secondary battery 54 Case body 55, 75, 85 bottom wall 56, 76, 86 Front wall 57, 77, 87 Rear wall 58, 78, 88 Side wall 59, 79 Bottom weight (weight part) 60, 95 Locking device 89 Bottom weight (weight part) 90, 91 Inner wall (weight section) 92 Front weight (weight part) 93 Rear weight (weight part) 94 Spacing adjustment plate

Claims

1. a battery case including a secondary battery and a case body that houses the secondary battery; a weight portion for adjusting the weight of the battery case, A battery device that can be housed in a battery compartment provided in a body of an industrial vehicle, The secondary battery is a non-lead battery-based high-density energy secondary battery, the battery case has a size smaller than the size of the battery compartment; a case box capable of accommodating the battery case and having a shape that fits the battery compartment; The battery device is characterized in that the weight portion is provided at least on the bottom and side portions of the case box.

2. 2. The battery device according to claim 1, wherein the weight of the case box is adjusted based on the height of the upper edge of the side portion on which the weight portion is provided.

3. 3. The battery device according to claim 1, wherein the case box is provided with a fastener for hanging.

4. 3. The battery device according to claim 1, wherein the secondary battery is a lithium ion secondary battery.

5. The car body and a battery device that can be housed in a battery compartment provided in the vehicle body, 5. An industrial vehicle, wherein the battery device is the battery device according to claim 1.

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