Battery pack usage methods and battery storage systems

Abstract

This invention provides a battery pack utilization method and a battery storage system that enable effective use of battery packs mounted on electric industrial vehicles or stationary battery storage systems. [Solution] The battery pack utilization method involves mutual use of a battery pack having multiple battery modules 18, which are configured by connecting lithium-ion secondary batteries 21 for storing electricity in series, between an electric forklift 1 and a stationary container battery storage system 30 or another electric forklift.

Description

Technical Field

[0001] The present invention relates to a method for using a battery pack and a battery storage system.

Background Art

[0002] For example, Patent Document 1 describes a battery storage system including a plurality of container-type storage batteries. The container-type storage battery includes a container, a pedestal housed in the container, and a plurality of module batteries mounted on the pedestal.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, as a forklift, which is one of industrial vehicles, the number of electric forklifts equipped with battery packs using lithium-ion secondary batteries has been increasing. By the way, industrial vehicles, like ordinary vehicles, may be sold as used vehicles by replacement. However, the reuse (recycling) of used battery packs has not advanced. Therefore, it is necessary to effectively use the battery packs mounted on electric forklifts. In addition, it is also necessary to effectively use the battery packs mounted on stationary battery storage systems such as container-type storage batteries as in the above prior art.

[0005] An object of the present invention is to provide a method for using a battery pack and a battery storage system that can effectively use the battery packs mounted on electric industrial vehicles or stationary battery storage systems.

Means for Solving the Problems

[0006] (1) One aspect of the present invention relates to a battery pack utilization method in which a battery pack having a plurality of battery modules, which are configured by connecting lithium-ion secondary batteries for storing electricity in series, is mutually utilized between an electric industrial vehicle and a stationary battery storage system or another electric industrial vehicle.

[0007] In this method of battery pack utilization, by mutually using battery packs between electric industrial vehicles and stationary battery storage systems or other electric industrial vehicles, battery packs installed in electric industrial vehicles can be reused in stationary battery storage systems or other electric industrial vehicles, and battery packs installed in stationary battery storage systems can be reused in electric industrial vehicles. This ensures the effective utilization of battery packs installed in electric industrial vehicles or stationary battery storage systems.

[0008] (2) In the battery pack utilization method described in (1) above, vehicle battery packs installed in industrial vehicles may be reused in a battery storage system.

[0009] In this configuration, even if an industrial vehicle becomes obsolete due to replacement or other reasons, the vehicle's battery pack is reused in the battery storage system, ensuring that the vehicle's battery pack is effectively utilized.

[0010] (3) In the battery pack utilization method described in (2) above, the vehicle battery pack comprises a group of battery modules including multiple battery modules, a case housing the group of battery modules, a weight provided at the bottom of the case for balancing the weight of the vehicle battery pack, and a control unit for controlling the battery modules. The group of battery modules and the control unit of the vehicle battery pack may be reused in the battery storage system, but the weight of the vehicle battery pack may not be reused in the battery storage system.

[0011] In this configuration, the battery modules and control unit of the vehicle's battery pack are reused in the battery storage system, while the weight of the vehicle's battery pack is not reused in the battery storage system. Therefore, the weight of the battery storage system can be reduced, and unnecessary components in the battery storage system can be eliminated.

[0012] (4) Another aspect of the present invention is a stationary battery storage system comprising a plurality of stationary battery packs having a plurality of battery modules configured by connecting lithium-ion secondary batteries for storing electricity in series, wherein vehicle battery packs mounted on electric industrial vehicles are reused as stationary battery packs.

[0013] In such battery storage systems, vehicle battery packs installed in electric industrial vehicles are reused as stationary battery packs in stationary battery storage systems. This ensures that vehicle battery packs are effectively utilized even if industrial vehicles become obsolete due to replacement or other reasons.

[0014] (5) In the battery storage system described in (4) above, a mix of reused stationary battery packs, which are vehicle battery packs, and new stationary battery packs may be installed.

[0015] In this configuration, vehicle battery packs installed in industrial vehicles are reused as part of multiple stationary battery packs installed in the battery storage system, thus making effective use of the vehicle battery packs within the system. Furthermore, by reusing new stationary battery packs installed in the battery storage system as vehicle battery packs, the cost of vehicle battery packs is reduced compared to purchasing new battery packs specifically for vehicles. Therefore, stationary battery packs are effectively utilized within industrial vehicles.

[0016] (6) In (4) or (5) above, the multiple stationary battery packs are connected in parallel to each other, and each of the multiple stationary battery packs may be connected to a DC-DC converter that boosts the output voltage of the stationary battery pack.

[0017] In this configuration, even if the current output from each stationary battery pack differs due to varying degrees of degradation, the DC-DC converter boosts the output voltage of each stationary battery pack to the desired voltage. Therefore, even if stationary battery packs degrade, they can be fully utilized by installing them in the battery system without special selection.

[0018] (7) In any of (4) to (6) above, the vehicle battery pack may have a group of battery modules including a plurality of battery modules and a first case with a rectangular cross-section that houses the group of battery modules, and the stationary battery pack may have a second case with a rectangular cross-section that houses the group of battery modules.

[0019] In this configuration, a simple vehicle battery pack is obtained with a first case having a rectangular cross-section, matching the simple body structure of industrial vehicles. Then, corresponding to the vehicle battery pack, a simple stationary battery pack is obtained with a second case having a rectangular cross-section.

[0020] (8) In (7) above, the vehicle battery pack is provided at the bottom of the first case and has a weight for balancing the weight of the vehicle battery pack and a control unit for controlling the battery modules, while the stationary battery pack has the battery module group and control unit of the vehicle battery pack and does not have the weight of the vehicle battery pack.

[0021] In this configuration, the battery modules and control unit of the vehicle's battery pack are reused in the battery storage system, while the weight of the vehicle's battery pack is not reused in the battery storage system. Therefore, the weight of the battery storage system can be reduced, and unnecessary components in the battery storage system can be eliminated. [Effects of the Invention]

[0022] According to the present invention, battery packs mounted on electric industrial vehicles or stationary battery storage systems can be effectively utilized.

Brief Description of the Drawings

[0023] [Figure 1] It is a side view showing a forklift to which the method of using a battery pack according to an embodiment of the present invention is applied. [Figure 2] It is a perspective view of the vehicle battery pack shown in FIG. 1. [Figure 3] It is an exploded perspective view of the vehicle battery pack shown in FIG. 2. [Figure 4] It is a cross-sectional view of the vehicle battery pack shown in FIG. 1. [Figure 5] It is an exploded perspective view of the sub-pack shown in FIG. 4. [Figure 6] It is a front view (partially broken cross-sectional view) showing a container battery system according to an embodiment of the present invention. [Figure 7] It is a cross-sectional view of the stationary battery pack shown in FIG. 6. [Figure 8] It is a block diagram showing the configuration of the container battery system shown in FIG. 6.

Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0025] FIG. 1 is a side view showing a forklift to which the method of using a battery pack according to an embodiment of the present invention is applied. In FIG. 1, the forklift 1 according to the present embodiment is one of electric industrial vehicles.

[0026] The forklift 1 includes a vehicle body 2, front wheels 3 which are a pair of left and right drive wheels arranged at the front of the vehicle body 2, rear wheels 4 which are a pair of left and right steering wheels arranged at the rear of the vehicle body 2, and a loading and unloading device 5 arranged on the front side of the vehicle body 2.

[0027] The cargo handling device 5 includes a mast 6 erected at the front end of the vehicle body 2, a pair of left and right forks 9 mounted on the mast 6 via a lift bracket 7 so as to be able to be raised and lowered and capable of holding a pallet 8, a lift cylinder 10 for raising and lowering the forks 9, and a tilt cylinder 11 for tilting the mast 6.

[0028] Pallet 8 is a loading platform for carrying cargo M. Pallet 8 is, for example, a flat pallet. In plan view, pallet 8 has a roughly rectangular shape. Although not shown in the illustration, pallet 8 is provided with two fork holes into which each fork 9 is inserted.

[0029] Furthermore, the forklift 1 includes a travel motor 12 that rotates the front wheels 3, which are the drive wheels; a load handling motor 13 that rotates a hydraulic pump (not shown) that supplies hydraulic fluid to the lift cylinder 10 and tilt cylinder 11; and a vehicle battery pack 14 that is a power source for the travel motor 12 and the load handling motor 13.

[0030] Figure 2 is a perspective view of the vehicle battery pack 14. Figure 3 is an exploded perspective view of the vehicle battery pack 14. Figure 4 is a cross-sectional view of the vehicle battery pack 14. In Figures 2 to 4, the vehicle battery pack 14 comprises two sets of subpacks 15, a case 16 with a rectangular cross-section, and a control box 17.

[0031] As shown in Figures 4 and 5, the subpack 15 includes a battery module group 18A containing multiple (in this case, four) battery modules 18, a rectangular parallelepiped housing 19 that houses the battery module group 18A, and a monitoring unit 20 positioned on the housing 19.

[0032] The battery module 18 is constructed by connecting lithium-ion secondary batteries 21 in series to store electricity. Although not specifically shown in the diagram, the lithium-ion secondary battery 21 consists of a positive electrode, a negative electrode, a separator, and a frame, and an electrolyte is injected into the frame. Multiple battery modules 18 are connected in series.

[0033] The housing 19 has a rectangular cross-section housing 19a in which the battery module group 18A is arranged, and a flat plate-shaped lid 19b that covers the housing 19a. The housing 19 is made of a metal such as iron. The thickness of the housing 19a and the lid 19b are equal. Note that the lid 19b is omitted in Figure 5.

[0034] The monitoring unit 20 is a unit that monitors the status of the battery module 18. The status of the battery module 18 includes the voltage, charge level, and temperature of the battery module 18. The monitoring unit 20 has, for example, circuit boards 22 and 23 arranged vertically, a plurality of connecting members 24 that connect these circuit boards 22 and 23 to each other, and electronic components 25 mounted on the circuit boards 22 and 23. The monitoring unit 20 is composed of, for example, a CMU (Cell Motoring Unit).

[0035] Case 16 has a weight 26 and a pair of side plates 27 and a pair of side plates 28 fixed to the weight 26. The pair of side plates 27 are arranged opposite each other. The pair of side plates 28 are arranged opposite each other in a direction perpendicular to the direction in which the pair of side plates 27 face each other. Case 16 is made of a metal such as iron. The weight 26 forms the bottom plate of case 16. In other words, the side plates 27 and 28 work together with the weight 26 to form a first case, case 16, which houses the battery module groups 18A and monitoring unit 20 of two sets of subpacks 15. The weight 26 is located at the bottom of case 16.

[0036] The weight 26 is a balancing component used to balance the weight of the vehicle battery pack 14. The thickness of the weight 26 is greater than the thickness of the side plates 27 and 28. The weight 26 is, for example, rectangular in shape.

[0037] The control box 17 is a unit that controls the entire vehicle battery pack 14. The control box 17 is positioned across two sets of sub-packs 15. The control box 17 is attached to the monitoring unit 20. A harness 29 is connected to the control box 17.

[0038] The control box 17 detects abnormalities, deterioration, and failures in the battery module 18 based on monitoring information from the monitoring unit 20, and controls the battery module 18 to ensure the performance of the vehicle battery pack 14. The control box 17 is configured, for example, as a battery management system (BMS). The control box 17, in cooperation with the monitoring unit 20, constitutes a control unit that controls the battery module 18.

[0039] Figure 6 is a front view (partially broken cross-sectional view) showing a container battery system according to one embodiment of the present invention. In Figure 6, the container battery system 30 of this embodiment is a stationary battery system.

[0040] The container battery system 30 can be used, for example, as a backup power source during disasters, or to reduce the load on the power supply during peak hours when electricity demand is highest.

[0041] The container battery system 30 comprises a rectangular container 31. Inside the container 31 are multiple stationary battery packs 32, multiple DC-DC converters 33, and a power converter 34 (see Figure 8). In other words, the container battery system 30 comprises multiple stationary battery packs 32.

[0042] As shown in Figure 7, the stationary battery pack 32 comprises the two sets of subpacks 15, a case 35 with a rectangular cross-section, and the control box 17. The height dimension of the case 35 is smaller than the height dimension of the case 16 of the vehicle battery pack 14.

[0043] Case 35 has a bottom plate 36 and a pair of side plates 37 and a pair of side plates 38 fixed to the bottom plate 36. Case 35 is made of a metal such as iron. Case 35 constitutes a second case that houses two sets of battery module groups 18A and a monitoring unit 20, which are the same as those in the vehicle battery pack 14.

[0044] The thickness of the bottom plate 36 may be equal to the thickness of the side plates 37 and 38, or it may be greater than the thickness of the side plates 37 and 38. However, the thickness of the bottom plate 36 is less than the thickness of the weight 26 that forms the bottom plate of the case 16. In other words, the stationary battery pack 32 does not have the weight 26 of the vehicle battery pack 14.

[0045] Multiple stationary battery packs 32 are stored in a battery pack storage rack 39. Multiple DC-DC converters 33 and power converters 34 are placed on the top surface of the battery pack storage rack 39. Multiple DC-DC converters 33 and power converters 34 are located in the upper part of the container 31. Multiple DC-DC converters 33 are located in front of the power converters 34 within the container 31.

[0046] Inside container 31, reused stationary battery packs 32, which are derived from vehicle battery packs 14, and new stationary battery packs 32 are mixed together. The reused stationary battery packs 32 are used battery packs that were installed as vehicle battery packs 14 in forklift 1. The new stationary battery packs 32 are unused battery packs that were installed in vehicles such as forklift 1 or other stationary battery systems.

[0047] Multiple stationary battery packs 32 are connected in parallel to each other, as shown in Figure 8. The output voltage of the stationary battery packs 32 is, for example, 48V DC. A DC-DC converter 33 is connected to each stationary battery pack 32. The DC-DC converter 33 boosts the output voltage of the stationary battery packs 32. For example, the DC-DC converter 33 boosts 48V to 380V.

[0048] Each DC-DC converter 33 is connected to a power converter (PCS) 34. The power converter 34 converts the DC voltage from the DC-DC converter 33 to an AC voltage. For example, the power converter 34 converts 380V DC to 200V AC.

[0049] Between the forklift 1 and the container battery system 30, the vehicle battery pack 14 and the stationary battery pack 32 are mutually usable in both directions. A description of this battery pack utilization method will be provided.

[0050] For example, if forklift 1 is replaced and becomes obsolete, the vehicle battery pack 14 installed in forklift 1 is reused as a stationary battery pack 32 in the container battery storage system 30, as described below.

[0051] Specifically, the vehicle battery pack 14 mounted on the forklift 1 is first removed, and the two sets of sub-packs 15 and the control box 17 of the vehicle battery pack 14 are recovered. In other words, the battery module group 18A, housing 19, monitoring unit 20, and control box 17 of the vehicle battery pack 14 are recovered. Specifically, the two sets of sub-packs 15 and the control box 17 are removed from the case 16 of the vehicle battery pack 14.

[0052] Then, the two sets of sub-packs 15 and control boxes 17 are housed inside the case 35 of the stationary battery pack 32. In this state, the stationary battery pack 32 is mounted on the container battery storage system 30.

[0053] Therefore, the battery module group 18A, housing 19, monitoring unit 20, and control box 17 of the vehicle battery pack 14 are not disassembled and are reused as is in the stationary battery pack 32. The case 16 including the weight 26 in the vehicle battery pack 14 is not reused in the stationary battery pack 32.

[0054] Furthermore, used battery packs are cheaper than new ones. For this reason, there are cases where it is desirable to use the stationary battery pack 32 installed in the container battery system 30 as the vehicle battery pack 14 instead of purchasing a new battery pack. In this case, the stationary battery pack 32 installed in the container battery system 30 is reused as the vehicle battery pack 14 in the forklift 1 in the following manner.

[0055] Specifically, the stationary battery pack 32 mounted on the container battery system 30 is removed, and the two sets of sub-packs 15 and the control box 17 of the stationary battery pack 32 are recovered. In other words, the battery module group 18A, housing 19, monitoring unit 20, and control box 17 of the stationary battery pack 32 are recovered. Specifically, the two sets of sub-packs 15 and the control box 17 are removed from the case 35 of the stationary battery pack 32. Then, the two sets of sub-packs 15 and the control box 17 are placed in the case 16 of the vehicle battery pack 14. In this state, the vehicle battery pack 14 is mounted on the forklift 1.

[0056] Furthermore, the vehicle battery pack 14 may be mutually usable between forklift 1 and other forklifts. If the vehicle battery pack 14 installed on forklift 1 can be used on another forklift 1, the vehicle battery pack 14 installed on forklift 1 is removed and then installed on the other forklift.

[0057] As described above, in this embodiment, by mutually utilizing the vehicle battery pack 14 and the stationary battery pack 32 between the electric forklift 1 and the stationary container battery system 30, the vehicle battery pack 14 mounted on the electric forklift 1 can be reused in the stationary container battery system 30, and the stationary battery pack 32 mounted on the stationary container battery system 30 can be reused in the electric forklift 1. Furthermore, by mutually utilizing the vehicle battery pack 14 between the electric forklift 1 and other forklifts, the vehicle battery pack 14 mounted on the electric forklift 1 can be reused in other electric forklifts. This ensures that the vehicle battery pack 14 mounted on the electric forklift 1 or the stationary battery pack 32 mounted on the stationary container battery system 30 are effectively utilized.

[0058] Furthermore, in this embodiment, by reusing the vehicle battery pack 14 mounted on the forklift 1 in the container battery storage system 30, even if the forklift 1 is no longer used due to, for example, replacement of the forklift 1, the vehicle battery pack 14 mounted on the forklift 1 is reused in the container battery storage system 30, thus ensuring that the vehicle battery pack 14 is effectively utilized.

[0059] Furthermore, in this embodiment, the container battery system 30 contains a mix of reused stationary battery packs 32, which are derived from the vehicle battery pack 14, and new stationary battery packs 32. In this case, the vehicle battery pack 14 mounted on the forklift 1 is reused as part of the multiple stationary battery packs 32 mounted on the container battery system 30, thus making more effective use of the vehicle battery pack 14 for the container battery system 30. Also, by reusing the new stationary battery packs 32 mounted on the container battery system 30 as vehicle battery packs 14, the cost of vehicle battery packs 14 is lower compared to purchasing new battery packs for vehicle battery packs 14. Therefore, the stationary battery packs 32 are made even more effective use of the forklift 1.

[0060] Furthermore, in this embodiment, multiple stationary battery packs 32 are connected in parallel to each other, and each of the multiple stationary battery packs 32 is connected to a DC-DC converter 33 that boosts the output voltage of the stationary battery pack 32. Therefore, even if the current output from each stationary battery pack 32 differs due to different degrees of degradation among the multiple stationary battery packs 32, the DC-DC converter 33 boosts the output voltage of the stationary battery pack 32 to the desired voltage. Consequently, even if the stationary battery packs 32 degrade, they can be used up completely by installing them in the container battery storage system 30 without special selection.

[0061] Furthermore, in this embodiment, the vehicle battery pack 14 has a case 16 with a rectangular cross-section that houses the battery module group 18A, and the stationary battery pack 32 has a case 35 with a rectangular cross-section that houses the battery module group 18A. Therefore, a simple vehicle battery pack 14 with a case 16 with a rectangular cross-section can be obtained to match the simple body structure of the forklift 1. And, corresponding to the vehicle battery pack 14, a simple stationary battery pack 32 with a case 35 with a rectangular cross-section can be obtained.

[0062] Furthermore, in this embodiment, the battery module group 18A, monitoring unit 20, and control box 17 of the vehicle battery pack 14 are reused in the container battery system 30, while the weight 26 of the vehicle battery pack 14 is not reused in the container battery system 30. Therefore, the weight of the container battery system 30 can be reduced, or unnecessary parts in the container battery system 30 can be reduced, and multiple stationary battery packs 32 can be mounted in the container battery system 30 in a space-efficient manner.

[0063] The present invention is not limited to the embodiments described above. For example, in the above embodiment, the weight 26 forms the bottom plate of the case 16 in the vehicle battery pack 14, but the present invention is not limited to any particular form as long as the weight 26 is provided at the bottom of the case 16, and the weight 26 may be a separate component from the case 16. For example, the weight 26 may be placed below (towards the bottom) the subpack 15 inside the case 16, or the weight 26 may be fixed to the bottom surface of the bottom plate of the case 16. In this case, the thickness of the bottom plate of the case 16 may be equal to the thickness of the side plates 27 and 28 of the case 16. For example, the case 35 of the stationary battery pack 32 may be used as the case 16 of the vehicle battery pack 14.

[0064] Furthermore, although the monitoring unit 20 is arranged on the housing 19 in the above embodiment, the configuration is not limited to this, and the monitoring unit 20 may be housed inside the housing 19. In this case, the monitoring unit 20 is arranged on the battery module group 18A.

[0065] Furthermore, in the above embodiment, the case 16 of the vehicle battery pack 14 and the case 35 of the stationary battery pack 32 have a rectangular cross-section, but the shape of the cases 16 and 35 is not particularly limited to a rectangular cross-section.

[0066] Furthermore, in the above embodiment, the monitoring unit 20 and control box 17, which are part of the subpack 15, are arranged inside the case 16 in the vehicle battery pack 14, but the configuration is not limited to this. For example, the monitoring unit 20 and control box 17 may be configured as a single management unit, and this management unit may be housed inside the case or mounted on the top surface of the case. The same applies to the monitoring unit 20 and control box 17 of the stationary battery pack 32.

[0067] Furthermore, in the above embodiment, the vehicle battery pack 14 is mounted on an electric forklift 1, but the form is not particularly limited, and the vehicle battery pack 14 may be mounted on an electric industrial vehicle other than a forklift 1, such as a towing tractor. [Explanation of Symbols]

[0068] 1...Forklift (industrial vehicle), 14...Vehicle battery pack (battery pack), 16...Case (first case), 17...Control box (control unit), 18...Battery module, 18A...Battery module group, 20...Monitoring unit (control unit), 21...Lithium-ion secondary battery, 26...Weight, 30...Container battery storage system (battery storage system), 32...Stationary battery pack (battery pack), 33...DC-DC converter, 35...Case (second case).

Claims

1. A method for utilizing a battery pack, which involves the mutual use of a battery pack having multiple battery modules configured by connecting lithium-ion secondary batteries for storing electricity in series, between an electric industrial vehicle and a stationary battery storage system or another electric industrial vehicle.

2. The battery pack utilization method according to claim 1, wherein a vehicle battery pack mounted on the industrial vehicle is reused in the battery storage system.

3. The vehicle battery pack comprises a group of battery modules including the plurality of battery modules, a case housing the group of battery modules, a weight provided at the bottom of the case for balancing the weight of the vehicle battery pack, and a control unit for controlling the battery modules. The battery pack utilization method according to claim 2, wherein the battery module group and the control unit of the vehicle battery pack are reused in the battery storage system, and the weights of the vehicle battery pack are not reused in the battery storage system.

4. A stationary battery storage system comprising multiple stationary battery packs, each having multiple battery modules configured by connecting lithium-ion secondary batteries for storing electricity in series, A battery storage system in which vehicle battery packs installed in electric industrial vehicles are reused as stationary battery packs.

5. The battery storage system according to claim 4, wherein the vehicle battery pack is reused, and the stationary battery pack is mixed with a new stationary battery pack.

6. The aforementioned multiple stationary battery packs are connected in parallel to each other. The battery storage system according to claim 4, wherein each of the plurality of stationary battery packs is connected to a DC-DC converter that boosts the output voltage of the stationary battery pack.

7. The vehicle battery pack comprises a group of battery modules including the plurality of battery modules, and a first case with a rectangular cross-section that houses the group of battery modules. The battery storage system according to claim 4, wherein the stationary battery pack has a second case with a rectangular cross-section that houses the battery module group.

8. The vehicle battery pack is provided at the bottom of the first case and includes a weight for balancing the weight of the vehicle battery pack and a control unit for controlling the battery module. The battery storage system according to claim 7, wherein the stationary battery pack has the battery module group and the control unit of the vehicle battery pack, and does not have the weight of the vehicle battery pack.

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