Battery tray of a traction battery, in particular a lithium-ion traction battery, for a mobile work machine

Abstract

The invention relates to 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 provided with an additional weight (7) which is fastened to an outer wall of the battery tray (1). The additional weight (7) is formed as a composite material which comprises a ballast material (7a) and a composite compound (7b).

Description

[0001] 24327 / P24028-DEa / KBS= EM-KBS006 02 / 13 / 2025 - Geirhos

[0002] 1

[0003] Description

[0004] Battery tray for a traction battery, in particular a lithium-ion traction battery, for a mobile work machine

[0005] The invention relates to a battery tray for a traction battery, in particular a lithium-ion traction battery, for a mobile working machine, in particular a forklift truck, wherein the battery tray is provided with an additional weight which is attached to an outer wall of the battery tray.

[0006] 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.

[0007] 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.

[0008] Conventional traction batteries are relatively heavy lead-acid batteries that contribute significantly to the counter-torque against a load in the forklift. To prevent unstable conditions and the risk of the forklift tipping over, as well as during braking, the vehicle's weight and center of gravity are crucial. 24327 / P24028-DEa / KBS= EM-KBS006

[0009] February 13, 2025 - Geirhos

[0010] 2

[0011] 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.

[0012] 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.

[0013] 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.

[0014] Battery-electric industrial trucks that use lithium-ion traction batteries as high-performance batteries, with lithium-ion battery modules installed in the battery tray, have the disadvantage that the lower weight of the lithium-ion traction battery compared to a lead-acid traction battery (with lead-acid battery modules installed in the battery tray) alters the center of gravity of the entire industrial truck, thus affecting its stability and load-bearing capacity. 24327 / P24028-DEa / KBS= EM-KBS006

[0015] February 13, 2025 - Geirhos

[0016] 3

[0017] 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.

[0018] It is known from DE 102014 106644 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, if the plate-shaped additional weight is made of a steel plate, the additional weight incurs high manufacturing costs, which also results in high manufacturing costs for the battery tray with the additional weight.

[0019] The present invention is based on the objective of providing a battery tray of the type mentioned at the outset, which can be manufactured more cost-effectively.

[0020] This problem is solved according to the invention by the fact that the additional weight is designed as a composite material, in particular a dimensionally stable composite material, comprising a ballast material and a composite material.

[0021] An additional weight consisting of a dimensionally stable composite material, comprising a ballast material and a composite material, can be manufactured cost-effectively because inexpensive materials can be used as ballast materials, which harden together with the composite material to form a dimensionally stable composite. This results in a cost-effective additional weight, leading to reduced manufacturing costs for the battery tray equipped with the additional weight.

[0022] According to an advantageous embodiment of the invention, the composite material is designed as a resin, in particular a polymer resin. 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 form. 24327 / P24028-DEa / KBS= EM-KBS006

[0023] February 13, 2025 - Geirhos

[0024] 4

[0025] The condition is such that the resin can fill the cavities between the ballast material, thus achieving uniform wetting of the ballast material with the composite material, which ensures that the ballast material hardens into the solid composite material.

[0026] According to an advantageous embodiment of the invention, the ballast material is formed as metal parts, in particular metal scrap and / or steel scrap and / or iron scrap, and / or slag. Such metal parts and / or slag, formed as metal scrap and / or steel scrap and / or iron scrap, represent a cost-effective ballast material from which the additional weight can be produced in a cost-effective manner. 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 reduced to a desired size, in particular fine-grained granules.During the manufacturing process, the ballast material can be crushed to a desired size to achieve a high density, enabling the provision of a sufficiently heavy ballast with a small volume. After the ballast material and the composite material have hardened, the metal parts or the crushed slag material are bound within the hardened composite, resulting in a dimensionally stable composite material for ballast.

[0027] 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. Particularly preferably, the composite material comprises 98.5–97.5% by weight of ballast material and 1.5–2.5% by weight of composite material. It has been shown that with these percentages of composite material, sufficient wetting of the ballast material with the composite material is achieved during the production of the added weight, resulting in a solid composite material. 24327 / P24028-DEa / KBS= EM-KBS006

[0028] February 13, 2025 - Geirhos

[0029] 5

[0030] According to an advantageous embodiment of the invention, the battery tray has an outer shell with a base wall and a surrounding outer wall, wherein the additional weight is attached to the underside of the base wall. Attaching the additional weight to the outer wall of the battery tray, formed by the underside of the base wall, advantageously results in a low center of gravity for the battery tray and the traction battery manufactured with the battery tray. This leads to a favorable center of gravity position for a traction battery comprising the battery tray according to the invention when it is installed in a mobile work machine, for example, a forklift truck.

[0031] Alternatively, a corresponding additional weight made of the composite material can be arranged on one or more outer walls of the outer wall.

[0032] According to an advantageous embodiment of the invention, the additional weight is detachably attached to the outer wall, in particular by means of screw connections. The additional weight, which consists of the composite material, can be mechanically processed in the same way as a steel plate, so that, for example, mounting holes for screw connections can be easily produced in the composite material.

[0033] The invention further relates to a method for producing an additional weight for a battery trough according to the invention, comprising the following steps:

[0034] • Provide a pouring form;

[0035] • Providing the ballast material and the composite material;

[0036] • Filling the bulk mold with the ballast material and the composite material;

[0037] • Hardening of the ballast material and the composite material to form the composite material;

[0038] • Shaping the composite material.

[0039] The bulk form can be designed as a simple frame with a base into which the ballast material and the composite material are poured during the production of the added weight. 24327 / P24028-DEa / KBS= EM-KBS006

[0040] February 13, 2025 - Geirhos

[0041] 6

[0042] According to an advantageous embodiment of the invention, when filling the bulk form, the ballast material and the composite material are filled into the form as a mixture.

[0043] 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 bulk form.

[0044] According to an alternative and equally advantageous embodiment of the invention, the mixture is produced by spraying the ballast material with the composite. The ballast material is advantageously sprayed with the composite while being filled into the bulk mold. This allows a uniform coating of the ballast material with the composite to be achieved with a small amount of composite sprayed onto the ballast material falling into the bulk mold, ensuring that the ballast material hardens into the solid composite. The spraying of the ballast material can be carried out, for example, using a spray device.

[0045] According to an alternative and equally advantageous embodiment of the invention, the ballast material and the composite material are filled sequentially, i.e., one after the other, into the mold. With such a sequential filling of the mold with ballast material and composite material, the mold 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 mold. This allows a uniform wetting of the ballast material with the composite material to be achieved with a small quantity of composite material added to the ballast material in the mold, ensuring that the ballast material hardens into the solid composite material.

[0046] After the ballast material and the composite material have hardened to form the composite material, the metal parts forming the ballast material and / or the crushed slag material forming the ballast material are bound in the hardened composite material, so that the hardened composite material from 24327 / P24028-DEa / KBS= EM-KBS006

[0047] February 13, 2025 - Geirhos

[0048] 7

[0049] The material can be formed from the bulk form, and after forming from the bulk form, a dimensionally stable body is available as an additional weight that can be attached to the desired outer wall of the battery tray.

[0050] The invention further relates to a lithium-ion traction battery for a mobile work machine, in particular a forklift truck, with a battery tray according to the invention, wherein at least one lithium-ion battery module is installed in the battery tray provided with the additional weight. This allows the weight of the lithium-ion traction battery to be increased in a simple manner.

[0051] The mass of the additional weight made of composite material is preferably selected such that the weight of the battery tray according to the invention, equipped with the additional weight and in which lithium-ion battery modules are installed, and thus the weight of a lithium-ion traction battery having the battery tray according to the invention, is adapted and aligned with the weight of a lead-acid traction battery with the same external dimensions of the battery tray, so that in a forklift truck a replacement of a lead-acid traction battery by a lithium-ion traction battery equipped with the battery tray according to the invention is made possible without impairing the load-bearing capacity and stability of the forklift truck.

[0052] The invention offers a number of advantages.

[0053] The additional weight, made from ballast material such as scrap metal and composite material, can be used to create an external weight with minimal manufacturing effort, which can be attached to an outer wall of the battery trough to increase the weight.

[0054] The additional weight can be easily produced using a suitable bulk mold, as its production is independent of the battery tray's manufacture. The shape of the bulk mold, and therefore the shape of the additional weight produced from the ballast material and the composite material, is not bound to the shape of the battery tray, allowing the volume of the additional weight to be selected according to the required mass. 24327 / P24028-DEa / KBS= EM-KBS006 13.02.2025 - Geirhos

[0055] 8

[0056] The battery trough, to which the additional weight is attached from the outside, can have a simple structure and consist only of the bottom wall and the surrounding outer wall, thus enabling a simplified trough geometry of the battery trough, which leads to cost savings in terms of the manufacturing costs of the battery trough, especially if the battery trough is made from sheets welded together.

[0057] Furthermore, a short manufacturing time can be achieved with the battery trough according to the invention, since the manufacturing of the battery trough consisting of the base wall and the surrounding outer wall and the manufacturing of the additional weight are independent of each other and thus the manufacturing of the battery trough consisting of the base wall and the surrounding outer wall and the additional weight can take place in parallel.

[0058] Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiment shown in the schematic figures. Here,

[0059] Figure 1 shows a battery trough according to the invention with an additional weight formed of composite material in a sectional view and

[0060] Figure 2 shows a block diagram of the process for producing the additional weight of the battery tray of Figure 1.

[0061] Figure 1 shows a battery tray 1 according to the invention for a traction battery 2, for example a lithium-ion traction battery, for a mobile working machine, in particular a forklift truck.

[0062] The battery tray 1 is shown in a longitudinal section in Figure 1.

[0063] The battery trough 1 has an outer shell 4, which in the illustrated embodiment 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, and a [unclear text - likely a reference to a document or document number]

[0064] 9

[0065] The front wall, located in the front plane of the drawing, is not shown in detail in Figure 1, and the rear wall, located in the back plane of the drawing, is not shown in detail in Figure 1.

[0066] 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.

[0067] The battery tray 1 is equipped with an additional weight 7, which is attached to an outer wall of the battery tray 1.

[0068] In the illustrated embodiment, the outer wall is formed from the underside 5a of the base wall 5, to which the additional weight 7 is attached.

[0069] The additional weight 7 is detachably attached to the outer wall of the battery trough 1, for example by means of screw connections not shown in detail.

[0070] The additional weight 7 is formed from a composite material comprising a ballast material 7a and a composite material 7b.

[0071] In the battery trough 1 according to the invention, the space above the bottom wall 5 and within the outer wall 6 represents a cuboid receiving space 9 of the battery trough 1, into which at least one battery module 10, for example a lithium-ion battery module, can be installed for the production of the traction battery 2.

[0072] Figure 2 shows a block diagram of the process for producing the additional weight 7 consisting of the composite material.

[0073] In a first step S1, a bulk form is provided which determines the shape of the additional weight 7.

[0074] In a second step S2, the ballast material 7a and the composite material 7b are provided. 24327 / P24028-DEa / KBS= EM-KBS006

[0075] February 13, 2025 - Geirhos

[0076] 10

[0077] The ballast material 7a preferably consists of crushed metal parts. The metal parts are preferably scrap metal, steel scrap, or iron scrap, which can be crushed to a desired size before being filled into the bulk form. 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 7a. This slag material can be in the form of slag material crushed to a desired size, especially fine-grained granules.

[0078] Composite material 7b 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.

[0079] In a subsequent third step S3, the mold is filled with a desired quantity of ballast material 7a and composite material 7b. The ballast material 7a and the composite material 7b filled into the mold constitute a ballast filling.

[0080] In the third step S3, a mixture can be produced from the ballast material 7a and the composite material 7b, for example in a mixing device, which is then filled into the bulk form.

[0081] Alternatively, in the third step S3, the ballast material 7a can be filled into the bulk form and the ballast material 7a falling into the bulk form can be sprayed with the composite material 7b before impact in the bulk form, for example by means of a suitable spraying device, in order to create a mixture of ballast material 7a and composite material 7b filled into the bulk form.

[0082] Alternatively, in the third step S3, the ballast material 7a and the composite material 7b can be sequentially and thus successively filled into the bulk form, whereby first a desired quantity of ballast material 7a and then a desired quantity of composite material 7b are filled into the bulk form. 24327 / P24028-DEa / KBS= EM-KBS006

[0083] February 13, 2025 - Geirhos

[0084] 11

[0085] In a subsequent fourth step S4, the ballast material 7a and the composite material 7b are hardened to form a solid and dimensionally stable composite material.

[0086] In a subsequent fifth step S5, the composite material is shaped.

[0087] The hardened composite material can then be used for the production of the battery trough 1 or the production of the traction battery 2, where the additional weight 7 consisting of the hardened composite material can be attached and mounted to the corresponding outer wall of the battery trough 1.

[0088] The invention is not limited to the embodiment shown.

[0089] The ballast material 7a and composite material 7b that has been poured into the mold can be compacted after the third step S3 of filling the mold and before the fourth step S4 of curing.

[0090] For this purpose, the bulk form filled with ballast material 7a and binding agent 7a can be vibrated. A vibrating table can be provided for this purpose, on which the filled bulk form stands.

[0091] Compaction or vibration creates a bond between the ballast material 7a and the composite material 7b, resulting in uniform wetting of the ballast material 7a by the composite material 7b. Furthermore, compaction or vibration easily produces a flat surface for the ballast filling 3 in the bulk form.

Claims

24327 / P24028-DEa / KBS= EM-KBS006 02 / 13 / 2025 - Geirhos 12 Patent claims 1. 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 provided with an additional weight (7) which is attached to an outer wall of the battery tray (1), characterized in that the additional weight (7) is designed as a composite material comprising a ballast material (7a) and a composite material (7b).

2. Battery tray according to claim 1, characterized in that the composite material (7b) is designed as a resin, in particular a plastic resin.

3. Battery trough according to claim 1 or 2, characterized in that the ballast material (7a) is designed as metal parts, in particular metal scrap and / or steel scrap and / or iron scrap, and / or slag.

4. Battery trough according to one of claims 1 to 3, characterized in that the composite material comprises 99.5 - 95 wt percent ballast material (7a) and 0.5 - 5 wt percent composite material (7b).

5. Battery trough according to one of claims 1 to 4, characterized in that the battery trough (2) has an outer shell (4) with a bottom wall (5) and a circumferential outer wall (6), wherein the additional weight (7) is attached to the underside (5a) of the bottom wall (5).

6. Battery tray according to one of claims 1 to 5, characterized in that the additional weight (7) is detachably attached to the outer wall, in particular by means of screw connections.

7. Method for producing an additional weight (7) of a battery tray (1) according to one of claims 1 to 6, characterized by the following steps: • Provide a pouring form; • Providing the ballast material (7a) and the composite material (7b); 24327 / P24028-DEa / KBS= EM-KBS006 February 13, 2025 - Geirhos 13 • Filling the bulk form with the ballast material (7a) and the composite material (7b); • Curing of the ballast material (7a) and the composite material (7b) to form the composite material; • Shaping the composite material.

8. Method according to claim 7, characterized in that when filling the bulk form, the ballast material (7a) and the composite material (7b) are filled into the bulk form as a mixture.

9. Method according to claim 8, characterized in that the mixture is produced by spraying the ballast material (7a) with the composite material (7b).

10. Method according to claim 7, characterized in that when filling the bulk form, the ballast material (7a) and the composite material (7b) are sequentially filled into the bulk form.

11. Lithium-ion traction battery (2) for a mobile working machine, in particular a forklift truck, with a battery trough (1) according to one of claims 1 to 6, wherein at least one lithium-ion battery module (10) is installed in the battery trough (1) provided with the additional weight (7).

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