Method for producing a battery tray of a traction battery for a mobile work machine

Abstract

The invention relates to a method for producing a battery tray (1) of a traction battery (2), in particular a lithium-ion traction battery, for a mobile work machine, in particular an industrial truck, wherein the battery tray (1) is at least partially filled with a ballast filling (3), wherein the ballast filling (3) comprises a ballast material (3a) and a bonding substance (3b), wherein the battery tray (2) has an outer casing (4) with a base wall (5) and a peripheral outer wall (6). The method comprises the steps of: providing the battery tray (1) and the ballast filling (3); filling the battery tray (1) with the ballast filling (3); producing a flat surface (8) of the ballast filling (3), wherein the flat surface (8) extends up to the peripheral outer wall (6); setting the ballast filling (3) to form a laminate material.

Description

[0001] 24326 / P24027-DEa / KBS= EM-KBS005

[0002] February 13, 2025 - Geirhos

[0003] 1

[0004] Description

[0005] Method for manufacturing a battery rietrog of a traction battery for a mobile work machine

[0006] The invention relates to a method for manufacturing a battery trough for a traction battery, in particular a lithium-ion traction battery, for a mobile working machine, in particular a forklift truck, wherein the battery trough is at least partially filled with a ballast filling, wherein the ballast filling comprises a ballast material and a composite material, wherein the battery trough has an outer shell with a bottom wall and a circumferential outer wall.

[0007] A mobile work machine powered by a battery-electric drive, in particular a battery-electric industrial truck, for example a battery-electric counterbalance forklift, has a traction battery to provide the electrical drive energy. The traction battery has a battery tray in which one or more battery modules are installed. In known battery-electric industrial trucks, the traction battery is usually designed to be replaceable, so that a discharged traction battery can be easily replaced with a charged one during operation of the industrial truck.

[0008] Electrically powered industrial trucks, such as counterbalance forklifts, have a lifting mast with a load-handling device, such as a fork, on the front axle. The stability of such trucks with a load is crucially determined by the vehicle's overall center of gravity, which in turn depends on the position of the counterweight, as well as the position and weight of the traction battery.

[0009] Conventional traction batteries are relatively heavy lead-acid batteries that contribute significantly to the counter-torque against a load in the industrial truck. To prevent unstable conditions and the risk of a 24326 / P24027-DEa / KBS= EM-KBS005

[0010] February 13, 2025 - Geirhos

[0011] 2

[0012] To prevent the forklift from tipping over, the vehicle weight and center of gravity are also important when braking.

[0013] Newer technologies now allow for the production and industrial use of batteries and accumulators that offer improved performance. These batteries can be described as high-performance batteries, characterized by a higher energy density relative to weight and / or volume compared to lead-acid batteries, and by the use of a different energy storage technology than a lead-acid reaction. Many high-performance batteries also feature the ability to deliver high power during discharge and / or charge at high power. The typical energy densities relative to weight and / or volume of a high-performance battery are higher than, and outside the range of, the corresponding parameters for lead-acid batteries, at least for one of these two values.

[0014] Lithium-ion batteries, which have achieved a level of reliability suitable for mass production, are increasingly being used on a larger scale than such high-performance batteries. They are characterized by high energy density, have only a low memory effect, and allow for high-power discharge and charging of the battery.

[0015] The use of such high-performance batteries is particularly advantageous in mobile machinery, for example industrial trucks, as traction batteries, because due to the high energy density in relation to the volume, a larger amount of electrical energy can be stored in the given installation space for the traction battery, thus increasing the range of a vehicle or the operating time of the industrial truck.

[0016] However, in battery-electric industrial trucks where a lithium-ion traction battery is used as a high-performance battery, with lithium-ion battery modules installed in the battery tray, the disadvantage arises that the lower weight of the lithium-ion traction battery compared to a lead-acid traction battery, where lead-acid batteries are installed in the battery tray, 24326 / P24027-DEa / KBS= EM-KBS005

[0017] February 13, 2025 - Geirhos

[0018] 3

[0019] Battery modules are installed, which changes the center of gravity of the entire industrial truck and thus the stability and load-bearing capacity of the industrial truck.

[0020] Therefore, there is a need to align the weight of a lithium-ion traction battery with the weight of a lead-acid traction battery with the same external dimensions of the battery tray, so that a lead-acid traction battery can be replaced by a lithium-ion traction battery in the industrial truck without affecting the load-bearing capacity and stability of the industrial truck.

[0021] It is known from DE 10 2014 106 644 B4 to attach a plate-shaped additional weight to the outside of the battery tray of a lithium-ion traction battery of a forklift truck, using fasteners, in order to equalize the weight of the lithium-ion traction battery with that of a lead-acid traction battery with the same size battery tray. However, such a plate-shaped additional weight and the required fasteners result in a high degree of construction complexity.

[0022] To increase the weight of a lithium-ion traction battery for a mobile work machine, it is also possible to partially fill the battery tray with ballast. In the first process step of manufacturing the battery tray, a mixture of metal parts and a composite material is produced as ballast. This mixture is then poured into the battery tray in a second process step, where it hardens into a composite material. The battery tray has a double-walled structure with an outer and an inner wall, and the ballast is filled into the space between these two walls.

[0023] However, a disadvantage here is that the battery tray with its double-walled construction causes high manufacturing costs.

[0024] The present invention is based on the objective of providing a method for manufacturing a battery tray of the aforementioned type, which is improved with regard to the aforementioned disadvantages. 24326 / P24027-DEa / KBS= EM-KBS005

[0025] February 13, 2025 - Geirhos

[0026] 4

[0027] This problem is solved according to the invention in a method for manufacturing a battery trough for a traction battery, in particular a lithium-ion traction battery, for a mobile working machine, in particular a forklift truck, wherein the battery trough is at least partially filled with a ballast filling, wherein the ballast filling comprises a ballast material and a composite material, wherein the battery trough has an outer shell with a bottom wall and a circumferential outer wall, by the steps of:

[0028] • Providing the battery tray and ballast filling

[0029] • Filling the battery tray with ballast

[0030] • Creating a flat surface for the ballast filling, with the flat surface extending to the surrounding outer wall.

[0031] • Hardening of the ballast filling to form a composite material.

[0032] In the inventive method, after filling the battery trough with the ballast, a flat and thus level surface of the ballast is created, extending to the surrounding outer wall. The ballast with this flat surface then hardens into a solid composite material. The flat surface of the ballast, and thus of the hardened composite material, extends to the surrounding outer wall and therefore forms a continuous surface parallel to the bottom wall of the battery trough, the base area of ​​which corresponds to the base area of ​​the bottom wall.On this flat surface of the ballast filling, and thus of the hardened composite material, one or more battery modules, for example lithium-ion battery modules, can be built and mounted during the production of a traction battery, without having to provide a separate and additional load-bearing intermediate floor on the battery tray to cover the ballast filling from above. In the method according to the invention, a battery tray can therefore be used that consists only of the bottom wall and the surrounding outer wall and requires minimal manufacturing effort.Furthermore, in the inventive method, the ballast filling is designed as a layer that is arranged on the bottom wall in the lower area of ​​the battery trough, which leads to a low center of gravity of the battery trough and the traction battery produced from the battery trough, thereby resulting in a low center of gravity when a traction battery having the battery trough according to the invention is installed in a mobile working machine, 24326 / P24027-DEa / KBS= EM-KBS005.

[0033] February 13, 2025 - Geirhos

[0034] 5, for example, a forklift truck, results in a favorable center of gravity position of the working machine.

[0035] According to an advantageous embodiment of the invention, the flat surface of the cured composite material is used as a separating plane to a receiving space of the battery tray, into which at least one battery module, in particular a lithium-ion battery module, is installed. If the flat surface of the ballast filling, and thus of the cured composite material, forms the separating plane to the receiving space of the battery tray, into which at least one battery module, in particular a lithium-ion battery module, is installed during the manufacture of the traction battery, the at least one battery module can be mounted directly on the flat surface of the cured composite material without having to provide a separate and additional supporting intermediate floor on the battery tray to cover the ballast filling from above.

[0036] According to an advantageous embodiment of the invention, the ballast filling in the battery trough is compacted to produce a flat surface. Compaction allows the ballast filling in the trough to be easily and evenly distributed above the bottom wall with a particularly uniform thickness, thus easily creating a flat surface of the ballast filling that is, in particular, parallel to the bottom wall.

[0037] According to an advantageous embodiment of the invention, to produce a flat surface of the ballast filling, the battery tray filled with the ballast is vibrated. For this purpose, the ballast filling in the battery tray can be shaken using a vibrator. Preferably, the battery tray filled with ballast is vibrated using a vibrating plate on which the battery tray stands.

[0038] According to an advantageous embodiment of the invention, the composite material comprises 99.5–95% by weight of ballast material and 0.5–5% by weight of composite material. Preferably, the composite material comprises 99–97% by weight of ballast material and 1–3% by weight of composite material.

[0039] In particular, the composite material preferably comprises 98.5 - 97.5 wt% 24326 / P24027-DEa / KBS= EM-KBS005

[0040] February 13, 2025 - Geirhos

[0041] 6

[0042] Ballast material and 1.5–2.5% by weight of composite material. It has been shown that this percentage of composite material provides sufficient wetting of the ballast material, which then hardens into a solid composite material after being poured into the battery tray and the tray is shaken.

[0043] According to an advantageous embodiment of the invention, a resin, in particular a polymer resin, is used as the composite material. Suitable resins include common types such as epoxy resin or polyester resin, which can be in the form of a one-component or multi-component resin. Preferably, the resin is in a liquid state.

[0044] According to an advantageous embodiment of the invention, metal parts and / or slag are used as ballast material. Preferably, scrap metal, steel scrap, or iron scrap is used as the metal parts, which can be crushed to a desired size before being filled into the battery trough. Alternatively or additionally, slag from the steel industry, in particular slag from iron or steel production, so-called blast furnace slag or steelworks slag, can be used as ballast material, which can be in the form of slag material crushed to a desired size, especially fine-grained granules. By appropriately selecting the size of the metal parts and / or the crushed slag material, a flat surface of the ballast filling in the battery trough can be easily achieved by vibrating it.After the ballast filling has hardened into the composite material, the metal parts and / or the crushed slag material are bound in the hardened composite, so that one or more battery modules can be built and mounted directly onto the flat surface of the hardened ballast filling.

[0045] According to an advantageous embodiment of the invention, the ballast material and the composite material are filled into the battery trough as a mixture.

[0046] The mixture consisting of the ballast material and the composite material can be easily produced in a mixing device, such as a mixing machine, before filling the battery tray. 24326 / P24027-DEa / KBS= EM-KBS005

[0047] February 13, 2025 - Geirhos

[0048] 7

[0049] According to an alternative and equally advantageous embodiment of the invention, the mixture is produced by spraying the ballast material with the composite material. The ballast material is advantageously sprayed with the composite material while it is being filled into the battery trough. This allows a uniform coating of the ballast material with the composite material to be achieved with a small amount of composite material sprayed onto the ballast material falling into the battery trough, ensuring that the ballast material hardens into the solid composite material. The spraying of the ballast material can be carried out, for example, using a spray device.

[0050] According to an alternative and equally advantageous embodiment of the invention, the ballast material and the composite material are filled into the battery tray sequentially, i.e., one after the other. With such a sequential filling of the battery tray with ballast material and composite material, the battery tray is filled with at least one layer of ballast material and one layer of composite material, wherein first a desired quantity of ballast material and then a desired quantity of composite material are filled into the battery tray. This allows a uniform wetting of the ballast material with the composite material to be achieved with a small quantity of composite material poured onto the ballast material already in the battery tray, ensuring that the ballast material hardens into the solid composite material.

[0051] The invention further relates to a lithium-ion traction battery for a mobile work machine, in particular a forklift truck, using a battery tray manufactured according to the invention, wherein there is no intermediate floor, in particular an intermediate sheet, in the battery tray between the flat surface of the hardened ballast filling and the at least one lithium-ion battery module.

[0052] With the battery trough according to the invention, a lithium-ion traction battery can thus be manufactured using a simple and cost-effective battery trough consisting only of the base wall and the surrounding outer wall, and provided with the ballast filling, in which lithium-ion battery modules are used without an additional intermediate floor, in particular an intermediate sheet, 24326 / P24027-DEa / KBS= EM-KBS005 13.02.2025 - Geirhos

[0053] 8 of the battery tray can be mounted directly on the flat surface of the hardened ballast filling.

[0054] The invention offers a number of advantages.

[0055] In the battery trough according to the invention, no intermediate floor, in particular no intermediate sheet, is required above the ballast filling to cover it and create a flat mounting surface for the at least one battery module. This results in reduced material usage for the battery trough, as it consists only of the bottom wall and the surrounding outer wall. Furthermore, the elimination of the intermediate floor above the ballast filling leads to a simplified trough geometry, resulting in cost savings in terms of manufacturing costs, especially when the battery trough is made from welded sheets, since no welds are required for an intermediate floor.

[0056] In the battery trough according to the invention, the ballast filling, which is formed with a uniform thickness above the bottom wall, results in a low center of gravity and a uniform weight distribution of the battery trough provided with the ballast filling.

[0057] Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiment shown in the schematic figures. Here,

[0058] Figure 1 shows a battery tray produced according to the inventive method in a sectional view and

[0059] Figure 2 shows a block diagram of the method according to the invention.

[0060] Figure 1 shows a battery tray 1 of a traction battery 2, for example a lithium-ion traction battery, produced according to the inventive method, for a mobile working machine, in particular a forklift truck, 24326 / P24027-DEa / KBS= EM-KBS005

[0061] February 13, 2025 - Geirhos

[0062] Figure 9 shows the battery tray 1 being at least partially filled with ballast 3 to increase weight.

[0063] The battery tray 1 is shown in a longitudinal section in Figure 1.

[0064] The battery trough 1 has an outer shell 4, which consists of a bottom wall 5 having a rectangular base and a surrounding outer wall 6. The outer wall 6 comprises a left outer wall 6a, a right outer wall 6b, a front wall located at the front in the plane of the drawing (not shown in detail in Figure 1), and a rear wall located at the rear in the plane of the drawing (not shown in detail in Figure 1).

[0065] The bottom wall 5 and the outer wall 6 are preferably formed from sheets, in particular steel sheets, which are welded to the battery trough 1.

[0066] The ballast filling 3 comprises a ballast material 3a and a composite material 3b, which are poured from above into the upwardly open battery trough 1.

[0067] In the battery trough 1 according to the invention, the space above the bottom wall 5 and within the outer wall 6 forms a cuboid-shaped filling chamber, which is partially filled with the ballast 3. The filling chamber is completely open at the top, i.e., at the upper edge of the outer wall 6, with the inner surfaces of the outer wall 6 forming a rectangular filling opening whose area corresponds to the base area of ​​the bottom wall 5. The battery trough 1 is thus provided with a filling chamber that is completely open at the top. The ballast 3 is poured into the filling chamber through the filling opening and falls onto the bottom wall 5.

[0068] The finished ballast filling 3 forms a layer resting on the bottom wall 5 with a thickness D required for the desired weight increase. The finished ballast filling 3 has a flat and therefore level surface 8. The base area of ​​the flat surface 8 of the finished ballast filling 3 corresponds to the base area of ​​the bottom wall 5. The flat surface 8 extends to the surrounding outer wall 6, i.e., to the left outer wall 6a, to the right outer wall 6b, to the front wall, and to the rear wall. The flat surface 8 is preferably arranged as a continuous surface parallel to the bottom wall 5. 24326 / P24027-DEa / KBS= EM-KBS005

[0069] February 13, 2025 - Geirhos

[0070] 10

[0071] The flat surface 8 defines a separation plane to a receiving space 9 of the battery trough 1 formed above the ballast filling 3, into which at least one battery module 10, for example a lithium-ion battery module, can be installed.

[0072] In the traction battery 2 with the battery trough 1 according to the invention, the battery modules 10 are positioned and mounted directly and thus immediately, i.e. without an intermediate floor, for example an intermediate sheet, of the battery trough 1 on the flat surface 8 of the ballast filling 3.

[0073] Figure 2 shows a block diagram of the inventive method for producing the battery trough 1 provided with the ballast filling 3.

[0074] In a first step S1, the battery trough 1 and the ballast filling 3 are provided, which includes the ballast material 3a and the composite material 3b.

[0075] The ballast material 3a of the ballast filling 3 is preferably formed from crushed metal parts. Metal scrap, specifically steel scrap or iron scrap, is preferably used as the metal parts and can be crushed to a desired size before being filled into the battery trough 1. Alternatively or additionally, slag from the steel industry, in particular slag from iron or steel production, so-called blast furnace slag or steelworks slag, can be used as ballast material 3a. This slag material can be in the form of slag material crushed to a desired size, especially fine-grained granules.

[0076] Composite material 3b preferably consists of a resin, in particular a synthetic resin. The resin is preferably in a liquid state. Suitable resins include common types such as epoxy resin or polyester resin, which can be in the form of a one-component or multi-component resin.

[0077] In a subsequent second step S2, the battery trough 1 is filled with a desired quantity of ballast material 3a and composite material 3b, and thus with a desired quantity of ballast filling 3. 24326 / P24027-DEa / KBS= EM-KBS005

[0078] February 13, 2025 - Geirhos

[0079] 11

[0080] The ballast filling 3 is placed into the upwardly open filling space of the battery trough 1, which is formed by the bottom wall 5 and the outer wall 6.

[0081] In the second step S2, a mixture can be produced from the ballast material 3a and the composite material 3b, for example in a mixing device, which is then filled into the battery trough 1.

[0082] Alternatively, in the second step S2, the ballast material 3a can be poured into the battery trough 1 and the ballast material 3a falling into the battery trough 1 can be sprayed with the composite material 3b before it hits the battery trough 1, for example by means of a suitable spraying device.

[0083] Alternatively, in the second step S2, the ballast material 3a and the composite material 3b can be filled sequentially and thus one after the other, whereby first a desired amount of ballast material 3a and then a desired amount of composite material 3b is filled into the battery trough 1.

[0084] In a subsequent third step S3, the flat surface 8 of the ballast filling 3 is created.

[0085] To create the flat surface 8 of the ballast filling 3, the ballast filling 3 filled into the battery trough 1 is compacted.

[0086] Preferably, to produce the flat surface 8 of the ballast filling 3, the battery trough 1 filled with the ballast filling 3 is vibrated. For this purpose, a vibrating table can be provided on which the battery trough 1 with the ballast filling 3 stands.

[0087] In a subsequent fourth step S4, the ballast filling 3, consisting of the ballast material 3a and the composite material 3b, hardens into a solid composite material.

[0088] During curing, a bond continues to form between the ballast filling 3 and the battery tray 1. 24326 / P24027-DEa / KBS= EM-KBS005

[0089] February 13, 2025 - Geirhos

[0090] 12

[0091] In the battery trough 1 according to the invention, no intermediate floor, for example an intermediate sheet, of the battery trough 1 is required or provided above the flat surface 8 of the ballast filling 3, since after the ballast filling 3 has hardened, the composite material 3b, which is designed as a resin, binds the ballast material 3a, which is designed as metal parts and / or as crushed slag material.

[0092] After the ballast filling 3 has hardened into a solid composite material, the battery tray 1 can be used to manufacture a traction battery 2, for example, a lithium-ion traction battery, for a mobile work machine, in particular a forklift truck. In a fifth step S5, at least one battery module 10, for example, a lithium-ion battery module, is installed in the receiving space 9 of the battery tray 1, which is formed above the finished ballast filling 3. The battery modules 10 are positioned and mounted directly on the flat surface 8 of the ballast filling 3, i.e., without requiring an intermediate floor, for example, an intermediate plate, of the battery tray 1 that covers the ballast filling 3 from above.

[0093] The mass of the ballast filling 3 placed in the battery tray 2 is preferably selected such that the weight of the battery tray 1 according to the invention, which is provided with the ballast filling 3 and in which lithium-ion battery modules 10 are installed, is adapted and aligned with the weight of a lithium-ion traction battery having the same external dimensions of the battery tray 1 according to the invention, so that in a forklift truck a replacement of a lead-acid traction battery by a lithium-ion traction battery which is provided with the battery tray 1 according to the invention is made possible without impairing the load-bearing capacity and stability of the forklift truck.

[0094] The ballast filling 3, consisting of the ballast material 3a and the composite material 3b, thus represents a balancing weight or additional weight of the battery trough 1 in order to equalize a lithium-ion traction battery designed with the battery trough 1 according to the invention to the weight of a semi-acid traction battery with the same dimensions of the battery trough 1.

Claims

24326 / P24027-DEa / KBS= EM-KBS005 02 / 13 / 2025 - Geirhos 13 Patent claims 1. Method for manufacturing a battery tray (1) of a traction battery (2), in particular a lithium-ion traction battery, for a mobile working machine, in particular a forklift truck, wherein the battery tray (1) is at least partially filled with a ballast filling (3), wherein the ballast filling (3) comprises a ballast material (3a) and a composite material (3b), wherein the battery tray (2) has an outer shell (4) with a bottom wall (5) and a circumferential outer wall (6), characterized by the steps: • Providing the battery tray (1) and ballast filling (3); • Filling the battery tray (1) with the ballast filling (3); • Creating a flat surface (8) of the ballast filling (3), wherein the flat surface (8) extends to the surrounding outer wall (6); • Curing of the ballast filling (3) to form a composite material.

2. Method according to claim 1, characterized in that the flat surface (8) of the cured composite material as a separation plane to a receiving space (9) of the battery tray (1) is used, into which at least one battery module (10), in particular a lithium-ion battery module, is installed.

3. Method according to claim 1 or 2, characterized in that, in order to produce a flat surface (8) of the ballast filling (3), the ballast filling (3) filled into the battery trough (1) is compacted.

4. Method according to one of claims 1 to 3, characterized in that, in order to produce a flat surface (8) of the ballast filling (3), the battery trough (1) filled with the ballast filling (3) is shaken.

5. Method according to any one of claims 1 to 4, characterized in that the composite material comprises 99.5 - 95 weight percent ballast material (3a) and 0.5 - 5 weight percent composite material (3b). 24326 / P24027-DEa / KBS= EM-KBS005 02 / 13 / 2025 - Geirhos 14 6. Method according to one of claims 1 to 5, characterized in that a resin, in particular a plastic resin, is used as the composite material (3b).

7. Method according to one of claims 1 to 6, characterized in that metal parts and / or slag are used as ballast material (3a).

8. Method according to one of claims 1 to 7, characterized in that the ballast material (3a) and the composite material (3b) are filled into the battery trough (1) as a mixture.

9. Method according to claim 8, characterized in that the mixture is produced in a mixing device.

10. Method according to claim 8, characterized in that the mixture is produced by spraying the ballast material (3a) with the composite material (3b).

11. Method according to one of claims 1 to 7, characterized in that the ballast material (3a) and the composite material (3b) are sequentially filled into the battery trough (1).

12. Lithium-ion traction battery (2) for a mobile working machine, in particular a forklift truck, using a battery tray (1) manufactured according to one of claims 1 to 11, wherein at least one lithium-ion battery module (10) is installed in the battery tray (1) provided with the hardened ballast filling (3), wherein there is no intermediate floor, in particular intermediate sheet, in the battery tray (1) between the flat surface (8) of the hardened ballast filling (3) and the at least one lithium-ion battery module (10).

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