Forklift truck with traction battery

Abstract

A counterbalance forklift (1) which is battery-electrically powered and has a battery compartment (8) for a traction battery (16) into which both a lead-acid battery (9) and a high-performance battery (13) can be inserted, and has a counterweight (11) above or behind a rear axle (6), characterized in that a receiving position (10) for a counterweight (12) is provided, wherein the counterweight (12) is dimensioned such that its counter-moment with respect to a load moment on a front axle (2) corresponds to the counter-moment of the weight difference between the lead-acid battery (9) and the high-performance battery (13) in the position of the battery compartment (8), wherein the receiving position (10) is provided on or in the counterweight (11).

Description

[0001] The invention relates to a counterbalance forklift truck that is battery-electrically powered and has a battery compartment for a traction battery, into which both a lead-acid battery and a high-performance battery can be inserted. The invention further relates to a system comprising such a counterbalance forklift truck, a lead-acid battery, and a high-performance battery.

[0002] Traction batteries are used to operate battery-electric mobile machinery, particularly industrial trucks such as forklifts. These batteries are typically interchangeable and can be inserted into a battery compartment. Once discharged, they can be replaced with a fully charged traction battery. Currently, these traction batteries are generally lead-acid accumulators, where a chemical reaction between sulfuric acid and lead stores electrical energy. The individual lead cells of such a traction battery are housed in a container or battery tray, which can be transported and handled using appropriate equipment, such as another forklift or industrial truck. Due to the lead content, the traction battery is quite heavy.

[0003] Counterbalance forklifts, which are used both with combustion engines and, in large numbers, as battery-electric vehicles with a traction battery, have a lifting mast with load-handling devices, in particular a load fork, on the front axle. The center of gravity of a lifted load lies in front of the front axle, and the resulting load moment, which rotates the counterbalance forklift forward around the front axle and generates a forward tipping moment, is counterbalanced by a counterweight above or behind the rear axle. When determining the required counter-moment to counteract the load moment of the counterbalance forklift's maximum permissible load, the moment of the traction battery, with its considerable weight, is also taken into account in the case of battery-electric forklifts.

[0004] 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. 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 exceed, the corresponding values ​​for lead-acid batteries for at least one of these two parameters.

[0005] While nickel-cadmium batteries do not offer a significant weight advantage, they have up to three times the energy density per unit volume. Other well-known technologies for accumulators or rechargeable batteries using nickel include nickel-metal hydride, nickel-iron, nickel-hydrogen, nickel-zinc, and silver-zinc. Sodium-nickel chloride and sodium-sulfur accumulators are also known.

[0006] However, lithium-ion batteries are increasingly being used on a larger scale. These batteries have achieved a level of reliability suitable for mass production, are characterized by high energy density, exhibit only a minimal memory effect, and allow for high-power discharge and charging. Various lithium-ion battery technologies are also known, such as lithium polymer, lithium cobalt dioxide, lithium air, lithium titanate, lithium iron phosphate, lithium manganese, and tin-sulfur lithium ions.

[0007] The use of such high-performance batteries is particularly advantageous in vehicles and, for example, industrial trucks, 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 battery, thus increasing the range of a vehicle or the operating time of the industrial truck.

[0008] However, battery-electric counterbalance forklifts, especially those using high-performance lithium-ion batteries, suffer from the disadvantage that the lower weight of the traction battery means that sufficient counter-torque to the load weight is no longer guaranteed. For example, replacing an existing lead-acid battery with a lithium-ion battery can result in a significant weight difference, given that a lead-acid battery typically has a density of 2700 kg / m³. 3 exhibits a density of approximately 2100 kg / m³ for a lithium-ion battery. 3The counterbalance forklift would then need to be equipped with a correspondingly larger counterweight. However, this is either not possible or involves disadvantages if the forklift is to be operated interchangeably with both lead-acid and lithium-ion batteries. To achieve the most compact counterbalance forklift possible and to make battery changes as simple and easy as possible, the traction battery is typically located between the axles, below the driver's seat. The effective lever arm of the traction battery's weight in relation to the counter-torque is therefore shorter than that of the counterweight. A comparable internal combustion engine-powered counterbalance forklift can thus achieve the same maximum permissible load capacity with a lower overall weight.

[0009] The present invention is therefore based on the objective of providing a counterbalance forklift truck and a system consisting of a counterbalance forklift truck and a traction battery as a high-performance battery, which avoids the aforementioned disadvantages, is inexpensive to manufacture and enables interchangeable operation between high-performance batteries and lead-acid batteries.

[0010] This problem is solved by a counterbalance forklift truck with the features of independent claim 1 and a system with the features of claim 6. Advantageous embodiments of the invention are specified in the dependent claims.

[0011] The object is achieved according to the invention by providing a receiving position for a counterbalance forklift truck which is battery-electrically driven and has a battery compartment for a traction battery, into which both a lead-acid battery and a high-performance battery can be inserted, wherein the counterbalance is dimensioned such that its counter-moment with respect to a load moment on a front axle corresponds to the counter-moment of the weight difference between the lead-acid battery and the high-performance battery in the position of the battery compartment.

[0012] This design allows for the use of both conventional lead-acid batteries and high-performance batteries, such as lithium-ion batteries, as traction batteries without altering the maximum load capacity or stability of the counterbalance forklift. The counterweight, for which a fixed mounting position is provided on the forklift, compensates for the reduced counter-torque when using a high-performance battery due to its lighter weight. This mounting position can be located as far away from the front axle as possible, for example, above or behind a rear axle in the area of ​​a counterweight. This means that a significantly lighter counterweight is sufficient compared to the weight difference between a lead-acid battery and a high-performance battery.In the receiving position, the counterweight can be secured by fasteners, particularly tool-free fasteners such as locking elements. It is also conceivable that the shape of the receiving position allows the counterweight to be held in place solely by gravity. Other possible solutions include hook elements for attaching the counterweight. In particular, the advantages of the high-performance battery's lighter weight are retained with regard to handling outside the counterbalance forklift.

[0013] The recording position is advantageously provided on or in a counterweight.

[0014] Due to the longer lever arm, a significantly lower weight is required than the weight difference between a lead-acid battery and a high-performance battery. For example, in a counterbalance forklift with a wheelbase of 1300 mm between the front and rear axles and a center of gravity of the traction battery 780 mm from the front axle, every kilogram saved only needs to be compensated for by 600 g in the distance to the rear axle. This corresponds to a weight reduction of 40%, which directly benefits a lower overall vehicle weight. The lower overall vehicle weight results in lower energy consumption and thus a greater range or longer operating time for the battery-electric counterbalance forklift.

[0015] The mounting position can be provided in the battery compartment. Advantageously, there is usually enough space left in the battery compartment to accommodate a flat, disc-shaped counterweight.

[0016] In one embodiment, the counterweight is removable and fixed in the receiving position.

[0017] The counterweight can be conveniently removed or attached without tools.

[0018] This allows an operator to switch between a lead-acid battery and a high-performance battery, or vice versa, at any time.

[0019] The task is also solved by a system consisting of a counterbalance forklift as previously described, a traction battery as a high-performance battery, a traction battery as a lead-acid battery and a counterweight.

[0020] In addition to the advantages already described, the system offers in particular the possibility of freely switching between a lead-acid battery and a high-performance battery as a traction battery.

[0021] Advantageously, the counterweight is attached to the high-performance battery and inserted into the battery compartment along with it.

[0022] If the counterweight uses the battery compartment as its mounting position, it can be advantageously designed so that it can be attached to the high-performance battery, for example, by hanging it on an external side wall.

[0023] Advantageously, the high-performance battery is a lithium-ion battery. Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiment shown in the schematic figure. The figure shows a counterbalance forklift truck according to the invention. 1, which is designed as a battery-electric vehicle. On one front axle 2 a lifting frame supports 3 with a lifting device 4 in the form of a load fork 5 off. Behind the front axle 2 and in front of a rear axle designed as a single wheel in the present example 6 It is located below a driver's seat. 7 a battery compartment 8 , into which, for example, a lead-acid battery 9 as a traction battery 16 is deployed. Into a recording position 10 , which are above the rear axle 6 as a subject in a counterweight 11 Once executed, a counterweight can be used. 12 are used and secured by locking devices that can be operated without tools and are not shown in detail.

[0024] The counterbalance forklift 1 , the lead-acid battery 9, the counterweight 12 and a high-performance battery 13 in the form of a lithium-ion battery 14 as an additional traction battery 16 together they form a system according to the invention. 15 If, as shown by the arrows, the lead-acid battery 9 against the high-performance battery 13 When the counterweight is replaced, the balance weight is also replaced. 12 into the recording position 10 This ensures that the full counter-moment to a load on the fork remains. 5 The load is maintained and there is no loss in the stability or maximum load capacity of the counterbalance forklift. 1 The advantages of the lighter weight of the high-performance battery 13 regarding handling when removing the battery from the battery compartment 8 remain intact and the overall vehicle weight is reduced when using the high-performance battery.13 This extends the operating time on a single battery charge. A distinction can be made between lead-acid batteries. 9 and the high-performance battery 13 They can be freely exchanged.

Claims

[1] Counterbalance forklift truck powered by battery electricity and featuring a battery compartment ( 8 ) for a traction battery ( 16 ) has a lead-acid battery ( 9 ) as well as a high-performance battery ( 13 ) can be used, characterized by that a recording position ( 10 ) for a counterweight ( 12 ) is provided, wherein the counterweight ( 12 ) is dimensioned such that its counter-moment with respect to a load moment on a front axle ( 2 ) the counter-moment of the weight difference between the lead-acid battery ( 9 ) and the high-performance battery ( 13 ) in the position of the battery compartment ( 8 ) corresponds. [2] Counterbalance forklift truck according to claim 1, characterized by that the recording position ( 10 ) on or in a counterweight ( 11 ) is planned. [3] Counterbalance forklift truck according to claim 1 or 2, characterized by that the recording position ( 10 ) in the battery compartment ( 8 ) is planned. [4] Counterbalance forklift truck according to any one of claims 1 to 3, characterized by that the counterweight ( 12 ) removable in the mounting position ( 10 ) is attached. [5] Counterbalance forklift truck according to claim 4, characterized by that the counterweight ( 12 ) can be disassembled or attached without tools. [6] System consisting of a counterbalance forklift truck ( 1 ) according to one of the preceding claims, a traction battery ( 16 ) as a high-performance battery ( 13 ), a traction battery ( 16 ) as a lead-acid battery ( 9 ) and a counterweight ( 12 ). [7] System according to claim 6, characterized by that the counterweight ( 12 ) on the high-performance battery ( 13 ) attached and inserted into the battery compartment ( 8) can be used. [8] System according to claim 6 or 7 characterized by that the high-performance battery ( 13 ) a lithium-ion battery ( 14 ) is.

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