Cooling system for a battery electrically driven vehicle

Abstract

The invention relates to a cooling system (10), in particular a high-voltage battery cooling system for a utility vehicle, comprising a battery unit (5'), a vehicle charger (14) for charging the battery unit (5') using externally supplied electrical energy, and an electric drive unit (5) driven by the electrical energy of the battery unit (5'), wherein the cooling system has a main cooling circuit (2) for cooling the coolant of the electric drive unit (5) and the vehicle charger (14), and a secondary cooling circuit (4) for cooling the coolant of the battery unit (5'), wherein the main cooling circuit (2) comprises a first circuit pump device (7), a heat exchanger (17) and a fan (18), wherein the secondary cooling circuit (4) comprises a second circuit pump device (7'), at least one heat exchanger (16) and a refrigeration device (19). According to the invention, the cooling system comprises a plurality of switchable multi-way valves (21, 22, 23, 24) for regulating the flow of coolant in the cooling circuits (2, 4), wherein the cooling circuits (2, 4) can be connected to one another or separated from one another by the multi-way valves (21, 22, 23, 24) in such a way that, in order to cool the electric drive unit (5) and the battery unit (5'), they can be operated selectively independently of one another and isolated from one another, or combined together in a connected manner.

Description

[0001] The present invention relates to a cooling system according to claim 1, a method according to claim 22, and a commercial vehicle according to claim 23.

[0002] Such cooling systems, temperature control systems, or thermal management systems are known and are particularly important in the field of battery-powered motor vehicles, such as passenger cars or commercial vehicles.

[0003] The aforementioned cooling system is primarily used to cool the drivetrain components of electrified powertrains, such as electric motors, inverters, battery packs, and on-board chargers. In this process, the corresponding coolant is delivered via a heat pump or coolant pump through coolant channels and cooling circuits, cooling the drivetrain components as it flows through them. The absorbed heat is then directed towards the heat exchanger / radiator on the coolant discharge side for release into the external environment.

[0004] However, known designs and systems primarily serve vehicle types that differ in size, structure, and function from Category O vehicles, such as trailers and semi-trailers. Electrified semi-trailers or general commercial vehicles typically use high-voltage batteries with high energy capacity (e.g., up to 300 kWh) as energy storage to power electric drive motors. These batteries can have nominal operating voltages of 600–1000 volts.

[0005] Battery cells or high-voltage battery packs are typically limited by installation space and must be mounted directly on the underside of the semi-trailer frame. Therefore, existing cooling systems often fail to meet spatial, mechanical, thermodynamic, or dynamic requirements. In any case, regulating electrified semi-trailers using existing systems is inefficient and can be designed to be more efficient.

[0006] The cooling system is primarily regulated via electronically controlled valves, such as multi-way valves. In principle, the large size and complexity of the high-voltage battery packs in electrified trailers or semi-trailers necessitate a consistently reliable solution to ensure adequate cooling management of both the electric drive unit and the battery cells under all conditions. While the battery system itself typically does not generate significant self-heating, other critical components of the drivetrain, such as inverters, motors, converters (e.g., DC-DC converters), and onboard chargers, generate substantial amounts of heat. This heat is channeled into the cooling system and typically released into the environment via heat exchangers.

[0007] The downside is that excessive pressure resistance within the cooling circuits or coolant channels of each cooling circuit often leads to excessive pressure loss, negatively impacting the overall energy efficiency of the cooling system. In the logistics industry, the largest application area for commercial vehicles and semi-trailer trucks to date, dynamic and extreme weather conditions result in inefficient cooling with significant energy losses. At high ambient temperatures, the temperature difference between the cooling system and the environment can become critical, especially for battery cells. These cooling systems often fail to adequately accommodate the actual temperature windows of the battery cells and electric drive unit components.

[0008] Furthermore, the integrability of the valves and their connection to existing heat pump units are crucial to ensure adaptability to diverse vehicle configurations. Therefore, overall, there is a significant need for optimization in terms of efficiency and functionality for such cooling systems, particularly when intended for use in battery-electric commercial vehicles or trailers with high-voltage batteries.

[0009] The purpose of this invention is to overcome these and other shortcomings of the prior art and to provide an improved and reliable cooling system for commercial vehicles that ensures energy-efficient cooling of the electric drive unit and battery unit.

[0010] The main features of the invention are given in the characterizing portion of claim 1. Embodiments are the subject of claims 2 to 23.

[0011] For a cooling system, particularly a high-voltage battery cooling system for commercial vehicles, the system includes a battery cell, an on-board charger for charging the battery cell using externally supplied electrical energy, and an electric drive unit driven by the electrical energy of the battery cell. The cooling system has a main cooling circuit for cooling the coolant in the electric drive unit and the on-board charger, and a secondary cooling circuit for cooling the coolant in the battery cell. The main cooling circuit includes a first-loop pump assembly, a heat exchanger, and a fan. The secondary cooling circuit includes a second-loop pump assembly, at least one heat exchanger, and a refrigeration device. The invention specifies that the cooling system includes multiple switchable multi-way valves for regulating the coolant flow rate in the cooling circuits. The cooling circuits can be interconnected or separated by these multi-way valves, allowing them to operate selectively and isolated from each other for cooling the electric drive unit and the battery cell, or to operate in combination and interconnected.

[0012] The operation of electric commercial vehicles or electric semi-trailers involves special requirements for efficient temperature regulation, which stem from unique thermodynamic challenges.

[0013] The cooling system of the present invention, along with the arrangement and optional switching function of the multi-way valves for regulating the cooling system and the two cooling circuits, produces a series of advantageous technical effects that, overall, positively impact the functionality, efficiency, cost, quality, and service life of the cooling system and the electrified trailer.

[0014] This advantageously allows the coolant to either circulate independently in the primary and secondary cooling circuits to cool the electric drive unit and battery unit, or to combine them into a common cooling circuit to cool the electric drive unit and battery unit. This results in an intelligent, demand-based control strategy that can dynamically respond to different operating states and environmental conditions, thereby maximizing the efficiency of the entire cooling system while minimizing energy demand.

[0015] A standalone main cooling circuit can only effectively dissipate the heat of the battery cell to a certain ambient temperature. Since the battery cell has a lower operating temperature compared to the drive components of the electric drive unit, the present invention advantageously provides an additional, active secondary cooling circuit to ensure cooling at higher temperatures.

[0016] Preferably, the coolant can be delivered to the components to be cooled in the electric drive unit and battery unit along a first flow direction via first and second loop pump devices. More preferably, after flowing through the components to be cooled, the coolant can be guided back to the heat exchanger or refrigeration equipment along a second flow direction. This ensures that the heat energy absorbed during the cooling process is always dissipated to the external environment.

[0017] According to a preferred embodiment, the electric drive unit may have at least one inverter and / or at least one converter. More preferably, the electric drive unit may have a dual drive unit, wherein the dual drive unit may include two motors and two associated inverters, and the electric drive unit may have at least one DC-DC voltage converter.

[0018] Preferably, the heat exchanger of the main cooling circuit can be configured as a radiator, wherein the heat exchanger and fan can be configured as a common radiator-fan unit. This results in a compact component unit that is easy to manufacture and inexpensive, through which the main cooling circuit can be operated and heat dissipation to the environment can be ensured. More preferably, the first circuit pump device can be configured as a coolant pump, wherein the coolant pump can use the radiator-fan unit as an additional auxiliary for delivering coolant during operation. This represents a particularly efficient method, especially from a fluid dynamics and energy perspective. This further improves the overall energy efficiency of the cooling system.

[0019] According to another preferred embodiment, all individual components of the electric drive unit and the on-board charger can be arranged and connected in parallel with the heat exchanger and fan of the main cooling circuit. Thus, during the cooling process in the main cooling circuit, the coolant can selectively flow through parallel-formed coolant channels and their connected components, and then flow back to the radiator-fan unit or the heat exchanger and fan to release the absorbed heat energy into the environment.

[0020] Preferably, the battery cell may have at least one high-voltage battery string, wherein the at least one high-voltage battery string includes at least three drive battery packs. More preferably, the battery cell may have three high-voltage battery strings, wherein each of the three high-voltage battery strings includes three drive battery packs, through which a coolant from a cooling system flows and cools the battery packs. The drive battery packs of the battery cells or battery strings to be cooled are electrically connected together, and preferably have a total nominal voltage of 600 V to 800 V, more preferably about 650 V to 660 V, particularly 655 V. The drive battery packs of the battery cells or battery strings to be cooled may have a total nominal energy capacity of about 300 kWh. These battery strings or the battery strings may also have a smaller or larger total nominal energy capacity.

[0021] Preferably, a heat exchanger can be arranged for each of the three high-voltage battery strings in the secondary cooling circuit. Two distribution elements can be provided in the secondary cooling circuit, one of which is connected to the third and fourth multi-way valves through a coolant channel, and the other of which is connected to the three heat exchangers through three branch coolant channels.

[0022] Preferably, each battery string may have additional distribution elements on its coolant supply side and discharge side, wherein the distribution elements of the battery string may be connected to the second loop pump and the heat exchanger respectively through coolant channels, and may also have three branch coolant channels for connection to the battery string. The distribution elements advantageously divide the coolant flow into three channels leading to the heat exchanger in a low-cost, simple, and reliable manner.

[0023] According to another preferred embodiment, the heat exchangers of the primary and / or secondary cooling circuits can be constructed in a plate shape as plate heat exchangers. This has proven to be a particularly efficient and cost-effective method for cooling. Furthermore, the plate shape utilizes the relatively large longitudinal area of ​​the semi-trailer frame, which is particularly advantageous given the inherent space constraints in implementation. The plate shape also supports uniform and efficient heat transfer and is easy to manufacture and inexpensive.

[0024] Preferably, the second-loop pump unit of the secondary cooling circuit can be a heat pump unit, which is already installed in the commercial vehicle or semi-trailer. The second-loop pump unit or heat pump unit circulates the coolant in the coolant passages of the secondary cooling circuit and provides sufficient flow pressure. Since the cooling system can be adapted to the already equipped heat pump unit, energy consumption is further reduced and overall energy efficiency is improved. This allows for efficient operation of the secondary cooling circuit for the battery cells and selective connection to refrigeration equipment.

[0025] According to another preferred embodiment, the coolant may be a water-ethylene glycol mixture. The composition of the coolant or water-ethylene glycol mixture allows it to be used for cooling individual components in both the primary and secondary cooling circuits. This advantageously provides a single coolant that can be effectively used for cooling in both cooling circuits, and achieves a reliable connection between the cooling circuits.

[0026] Preferably, automatic and adaptive adjustment can be achieved through the cooling system and multi-way valves, with the cooling system automatically adapting by utilizing special algorithms and state parameters. This advantageously enables automatic adjustment to meet different cooling needs. More preferably, an adaptive control algorithm can be implemented that not only is based on fixed limit values ​​but also dynamically responds to changes in the semi-trailer's operating state and environment. This further improves the efficiency of the cooling system.

[0027] According to a preferred embodiment, at least four multi-way valves are provided, wherein the main cooling circuit includes first and second multi-way valves, and the secondary cooling circuit includes third and fourth multi-way valves. Since two switchable multi-way valves are provided in each cooling circuit, multiple channel connection and switching options are enabled to construct the desired circuit. Through intelligent control of these four multi-way valves—that is, by selectively opening or closing coolant channels within the cooling circuits—the energy-intensive secondary active cooling circuit is activated only when needed, particularly for cooling the battery cells. In other operating states, the passive main cooling circuit is sufficient. This on-demand activation and switching of the cooling circuits significantly reduces energy consumption and increases the driving range of the electrified semi-trailer. In addition to reduced operating costs, less wear and tear and longer maintenance intervals also result in lower maintenance costs. This also has a positive overall impact on the total cost of ownership of the electrified trailer.

[0028] According to another preferred embodiment, the second multi-way valve can selectively connect the on-board charger and the electric drive unit in parallel to the main cooling circuit, while the first multi-way valve can selectively connect the main cooling circuit to the secondary cooling circuit. The parallel connection and arrangement of the on-board charger is particularly suitable for its targeted integration into the main cooling circuit, or for its targeted isolation from the main cooling circuit, for example, via a bypass circuit. The ability of the first multi-way valve to selectively connect the two cooling circuits as needed advantageously decouples the cooling of the battery cell from other components of the electric drive unit, thereby enabling on-demand temperature control. This reduces the operation of the secondary cooling circuit, resulting in reduced wear and thus extending the maintenance intervals of the system, the multi-way valve, and other system components. This, in turn, increases the overall lifespan of the system.

[0029] Preferably, the multi-way valves can be configured as 3 / 2-way valves, wherein the multi-way valves can be controlled and switched through a common control unit. 3 / 2-way valves are particularly suitable for the required circuitry and operating modes because these valves contain three passages and two switching positions. This allows all preset loops or sub-loops and their combinations to be implemented during cooling. The configuration as a common control unit also simplifies control at the software level and provides a simple implementation interface for algorithms and functions. These four highly integrated 3 / 2-way valves form a multi-way valve group, additionally supporting flexible and intelligent control of the cooling loops. Through integration, cooling loops can be combined or isolated as needed, thereby achieving more efficient cooling and reducing the overall system's energy requirements.

[0030] According to an alternative embodiment of the invention, a separate control unit can be provided, wherein the two control units for the main cooling circuit and the secondary cooling circuit are signal-connected and can act and operate collaboratively within the framework of the cooling system. This improves the flexibility and efficiency of handling the temperature control of the electric drive unit and the battery cell.

[0031] According to another preferred embodiment, the multi-way valve can be constructed separately and arranged in different locations within the cooling system, wherein the multi-way valve is designed to be modularly integrated into various locations within the cooling system. This flexibility advantageously enables the multi-way valve assembly to be used more widely in different vehicle configurations and further facilitates adaptation to specific design requirements. Based on the resulting modular integrability, simpler system installation and maintenance are achieved, while the adaptability of the cooling system is improved.

[0032] According to an alternative embodiment, the multi-way valve assembly, or four multi-way valves, can be formed as a single, uniform material structure, wherein the individual passages of the four multi-way valves can be formed on a common substrate. This advantageously saves installation space. Preferably, these passages can be arranged on the substrate, allowing for seamless fluid-tight connections between piping or coolant passages and valves via clamps. More preferably, the common substrate comprising all four multi-way valves can be constructed as a hollow cylinder. This provides a particularly compact solution that is inexpensive, easy to manufacture, and saves installation space. In fact, a disadvantage of valve assembly assemblies can be the additional space required for installation. Compared to conventional cooling systems that do not require a valve assembly consisting of four multi-way valves, valve positions in a valve assembly require more space. This can be particularly challenging in vehicle structures where available space is already limited. The measures described above significantly offset this problem.

[0033] According to another preferred embodiment, the main cooling circuit may have at least two parallel coolant channels, through which the main cooling circuit can be connected to the secondary cooling circuit, and these two coolant channels may be arranged after the first loop pump assembly of the main cooling circuit. The coolant channels provide a simple connection possibility and are advantageously used for connecting and combining the operation of two cooling circuits. This allows for the optimal selective distribution of coolant based on the operating conditions and temperature requirements of different components. This significantly improves the efficiency of the entire cooling system by always concentrating cooling capacity where it is most needed, while minimizing the total energy consumption for cooling.

[0034] According to another preferred embodiment, the first of the two coolant passages can be connected to the main cooling circuit via a first multi-way valve, and the second of the two coolant passages can be connected to the main cooling circuit via a T-shaped element. In this way, the multi-way valve can selectively act on the connection position of the coolant passages in the cooling system according to needs and the required cooling system operating mode, opening or closing the passages.

[0035] According to another preferred embodiment, the two coolant passages can be connected to refrigeration equipment via third and fourth multi-way valves, and also to at least one heat exchanger in the secondary cooling circuit. This allows for the connection or isolation of refrigeration equipment within the secondary cooling circuit as needed. Overall, this results in an additional improvement in the energy efficiency of the cooling system or multi-way valves.

[0036] Preferably, the main cooling circuit may have a flow sensor at each coolant passage of a component of the electric drive unit. More preferably, both cooling circuits may have one or more pressure sensors for measuring pressure in their respective coolant passages. This advantageously allows for continuous monitoring of sufficient coolant flow in the coolant passages during cooling and enables the derivation of pressure values ​​for controlling the cooling circuits.

[0037] The first-loop pump unit of the main cooling circuit is preferably formed by a compressor on both the coolant supply side and the discharge side. The first-loop pump unit is preferably equipped with a pressure sensor on both the coolant supply side and the discharge side, wherein the first pressure sensor is located on the coolant supply side at the output side of the first compressor, and the second pressure sensor is located on the coolant discharge side at the input side of the second compressor of the first-loop pump unit. This ensures that the pressure ratio and the potential pressure difference between the input and output are always determined, so that any possible pressure loss can be promptly and locally offset.

[0038] Preferably, advanced, modern sensors for accurately measuring pressure, temperature, and flow rate can be provided. This further improves control accuracy. Furthermore, data analytics and machine learning can be employed to predict and adjust cooling requirements in real time, further enhancing system responsiveness and efficiency.

[0039] Preferably, the main cooling circuit may include at least one compensation tank or expansion tank, wherein the compensation tank may be connected in parallel with the heat exchanger and arranged between the first loop pump unit and the heat exchanger of the main cooling circuit. More preferably, the secondary cooling circuit may have an additional compensation tank for each of the three battery strings, wherein the compensation tank of the secondary cooling circuit may be arranged between the battery cells (i.e., the three battery strings and six distribution elements arranged on the input and output sides) and the second loop pump unit. The compensation tank (also called an expansion vessel) of the cooling system ensures that the pressure of the entire system remains constant. The compensation tank absorbs excess coolant and minimizes overpressure in the cooling system. The compensation tank advantageously helps to keep the pressure rise during the expansion of the heated coolant to a minimum. It helps to operate or regulate the electric drive unit and battery cells at exactly the correct temperature.

[0040] More preferably, each of the three battery strings in the secondary cooling circuit can form its own internal sub-circuit with its assigned heat exchanger, so that the compensation tank can be arranged simultaneously between the coolant supply channel and the coolant discharge channel of the sub-circuit of the battery string.

[0041] The following additional measures and embodiments are primarily designed not only to improve the direct function of the multi-way valve, but also to enhance the overall efficiency and reliability of the cooling system in electrified semi-trailers.

[0042] According to a preferred embodiment, the multi-way valve may have a highly energy-efficient, modern drive unit, wherein the multi-way valve may include additional energy recovery devices. Advantageously, this reduces the energy consumption of the valve control unit itself. Overall, this further improves the overall energy efficiency of the electrified semi-trailer and cooling system.

[0043] According to another preferred embodiment, the multi-way valve can be configured as a proportional control valve. This allows for more precise flow regulation, which can provide advantages under specific operating conditions.

[0044] More preferably, the adjustment of cooling for the electric drive unit and battery unit, as well as the switching of the multi-way valves for the main cooling circuit and secondary cooling circuit, can be performed according to the ambient temperature and the operating status of the battery unit. When the electric drive unit is in driving mode, the battery unit can operate in discharge mode; when the on-board charger is connected or the electric drive unit is in braking mode, the battery unit can operate in charging mode.

[0045] Preferably, the main cooling circuit can be configured as passive. This cooling circuit is preferably constructed using a conventional cooling water system, where the energy absorbed by the cooling water is discharged into the environment through a radiator-fan unit. The main cooling circuit is responsible for cooling the electric drive unit and the on-board charger. These components operate over a relatively high temperature range; therefore, passive cooling dependent on ambient temperature is sufficiently effective. This avoids over-design and further reduces energy consumption.

[0046] In contrast, the secondary cooling loop can be active. Here, the energy stored in the cooling water is released into the environment through a heat exchanger integrated into the refrigeration unit. This preferably occurs through a phase change of the coolant from a gaseous to a liquid state. This loop is specifically designed to cool the battery cells because the battery cells have a lower thermal operating range than other components and must be effectively cooled even at higher ambient temperatures.

[0047] By intelligently controlling the multi-way valve based on ambient temperature and the operating status of the battery cells, the more energy-intensive secondary active cooling circuit is activated only when needed, specifically for cooling the battery strings of the battery cells. In other operating states, the passive primary cooling circuit is sufficient, further reducing energy consumption and thus increasing the driving range of the electrified semi-trailer. Overall, this provides intelligent control capabilities that allow cooling demands to be dynamically adjusted to adapt to individual environmental conditions. This means the system can automatically adjust cooling capacity based on current ambient temperature and vehicle operating conditions. This significantly contributes to energy efficiency and maintains optimal operating temperatures for the battery cells and electric drive unit components.

[0048] Preferably, the battery cell or individual battery strings of the battery cell and the drive battery pack can have an operating temperature of 0°C to 60°C in charging mode. More preferably, the battery cell or individual battery strings of the battery cell and the drive battery pack can have an operating temperature of -30°C to 60°C in discharging mode.

[0049] According to another preferred embodiment of the invention, in a first operating mode, i.e., when the ambient temperature is at least 15°C and the battery cell is operating in discharge mode, the switching method of the multi-way valve allows the main cooling circuit and the secondary cooling circuit to operate independently and isolated from each other. The main cooling circuit flows through all individual components and heat exchangers of the electric drive unit during cooling, while the secondary cooling circuit flows through the refrigeration equipment, distribution elements, heat exchangers, and battery cell during cooling. This intelligent switching and utilization of the multi-way valve ensures optimal cooling of each component while maximizing the energy efficiency of the entire system. This differentiated and independent control of the cooling circuit plays a crucial role in improving the performance of the electrified semi-trailer and reducing energy consumption. This mode is particularly relevant to driving a semi-trailer with a cooling system at higher ambient temperatures, when the battery cell is discharging and the electric motor drives the semi-trailer.

[0050] According to another preferred embodiment of the invention, in a second operating mode, i.e., when the ambient temperature is below 15°C and the battery cell is operating in discharge mode, the switching method of the multi-way valve allows the main cooling circuit and the secondary cooling circuit to operate in combination. The combined cooling circuit, during cooling, flows through all individual components of the electric drive unit and the heat exchanger of the main cooling circuit, as well as through the distribution elements, heat exchangers, and battery cell of the secondary cooling circuit. This targeted switching of the multi-way valve advantageously achieves optimal utilization of cooling resources in the second operating mode. This allows for effective cooling of the drive battery pack of the battery cell and the drive components of the electric drive unit even at lower ambient temperatures, while simultaneously greatly improving the energy efficiency of the entire cooling system. This mode is particularly relevant for driving a semi-trailer with a cooling system at low ambient temperatures, where the battery cell is discharging and the electric motor drives the semi-trailer.

[0051] According to another preferred embodiment, in a third operating mode, i.e., when the ambient temperature is at least 20°C and the battery cell is in charging mode, the switching method of the multi-way valve allows the main cooling circuit and the secondary cooling circuit to operate independently and isolated from each other. The main cooling circuit flows through the on-board charger and heat exchanger during cooling, while the secondary cooling circuit flows through the refrigeration equipment, distribution elements, heat exchanger, and battery cell during cooling. This isolated operating strategy maximizes the efficiency of the cooling system by optimizing the coolant and energy consumption requirements according to the trailer's operating status. This mode specifically relates to the charging status (stationary state) of the electrified semi-trailer, where the matched charging plug is connected to the on-board charger and uses external energy to charge the battery cell.

[0052] According to another preferred embodiment, in the fourth operating mode, i.e., when the ambient temperature is below 20°C and the battery cell is in charging mode, the switching method of the multi-way valve allows the main cooling circuit and the secondary cooling circuit to operate in combination. During cooling, the combined cooling circuit flows through the heat exchangers of the on-board charger and the main cooling circuit, as well as through the distribution elements, heat exchangers, and battery cells of the secondary cooling circuit. Overall, this operating condition provides an optimized solution for efficiently cooling the battery cell during charging at low ambient temperatures, thereby contributing to the overall efficiency and cost-effectiveness of the electrified semi-trailer and cooling system.

[0053] According to another preferred embodiment, the cooling device may include a PTC heating element for pre-treating the battery cells, wherein when the ambient temperature of the cooling system is below 0°C before initiating a charging mode for the battery cells, the battery cells can be heated to an operating temperature above 0°C by the PTC heating element in the secondary cooling circuit. At high ambient temperatures, the temperature difference between the cooling system and the environment can become critical, especially for the battery cells. Excessive temperature differences can impair the thermal integrity of the battery cells, potentially leading to shortened battery cell lifespan, performance degradation, or even damage. Pre-treatment using the PTC heating element of the cooling device significantly mitigates this effect.

[0054] The switching and regulation of the cooling system in pretreatment mode can preferably be similar to the third operating mode. When the battery strings of the battery cells are pretreated to achieve the optimal thermodynamic operating window, these four multi-way valves ensure that the coolant heated by the PTC element is dedicated to heating the drive battery without affecting other less temperature-sensitive drive components. This further improves the overall energy efficiency of the cooling system, as well as the efficiency and lifespan of the electrified semi-trailer. On the other hand, in colder climates where temperatures below 10°C (especially below 0°C) can be very detrimental to the battery system, effective heating or pre-temperature regulation of the system may be required. Such low temperatures can significantly impair battery performance and lifespan; therefore, integrating PTC heating elements represents a particularly advantageous solution.

[0055] According to another preferred embodiment, the second multi-way valve in the main cooling circuit can be switched during the battery cell's discharge mode to form a bypass circuit for the on-board charger and prevent coolant from flowing into the on-board charger's coolant passage. This advantageously reduces the pressure resistance within the cooling circuit and the multi-way valve. This is crucial to ensuring that the efficiency gained by the improved cooling system is not offset by increased pressure loss in the coolant passage. Lower pressure resistance ensures efficient coolant flow, which in turn further improves the overall performance of the cooling system. The bypass circuit achievable through the multi-way valve actively enables the deliberate bypassing of various auxiliary devices in the system when flow is unnecessary and lossy. This allows coolant to be supplied only to components that require cooling based on the current state of the electric drive unit and battery cell. This adjustment minimizes back pressure generated in the cooling system, further improving the overall efficiency of thermal management. Since the on-board charger is not needed during driving (as it does not charge the drive battery pack), back pressure in the piping, particularly in the on-board charger's coolant passage, can be bypassed. This measure reduces the required pump power, thereby reducing the energy consumption of the cooling system.

[0056] According to another preferred embodiment, the second multi-way valve and additional one-way valve of the main cooling circuit can be switched during the battery cell's charging mode, isolating the electric drive unit from the main cooling circuit and preventing coolant flow. This further reduces energy consumption because the components of the electric drive unit are inactive during the battery cell's charging mode, generating very little or no heat. By specifically isolating the electric drive unit, the coolant can cool the on-board charger more effectively, and less heat must be dissipated to the environment during return flow through the heat exchanger. This further improves the efficiency of the cooling system.

[0057] According to another preferred embodiment, the cooling system may have an emergency loop for emergency operation, wherein the emergency loop may form a sub-loop of the main cooling loop. The emergency loop may have at least one compressor for pumping purposes and two one-way valves that open during emergency operation, or whose switching mechanism ensures that the required components or circulating coolant can still be safely cooled during emergency operation. This allows the components of the battery cell and electric drive unit to continue to be effectively and safely cooled even under emergency operation. This optimizes the availability and robustness of the cooling system.

[0058] According to another preferred embodiment, the commercial vehicle can be formed by a train consisting of a tractor and trailers connected thereto and having at least one (preferably three) trailer axles, wherein the trailers may have electric drive units and battery units, and wherein a cooling system may be provided on the electrified trailers.

[0059] More preferably, the commercial vehicle may be a semi-trailer train, and the train is formed by a semi-trailer tractor driven by a conventional diesel engine and a semi-trailer connected thereto and having three trailer axles, wherein the semi-trailer may have an electric drive unit and a battery unit, and wherein a cooling system may be provided on the electrified semi-trailer.

[0060] More preferably, the electric drive unit can be arranged on the axle in the middle of the three trailer axles of the semi-trailer, wherein the battery unit can be supported on the bottom side of the semi-trailer frame.

[0061] In summary, the multi-way valve and cooling system of this invention provide a more flexible and efficient solution to meet the different cooling needs of electrified commercial vehicles or semi-trailers, and substantially promote performance improvement.

[0062] Other features, details, and advantages of the invention will become apparent from the claims, the specification, and the hereinafter described with reference to the accompanying drawings. The drawings show:

[0063] Figure 1 A schematic diagram of the first operating mode of the cooling system of the present invention.

[0064] Figure 2 A schematic diagram of the second operating mode of the cooling system of the present invention.

[0065] Figure 3 A schematic diagram of the third operating mode of the cooling system of the present invention.

[0066] Figure 4 A schematic diagram of the fourth operating mode of the cooling system of the present invention.

[0067] exist Figures 1 to 4 The cooling system, generally designated 10, is a high-voltage battery cooling system and is implemented on an electrified semi-trailer (not shown) of a commercial vehicle. Specifically, the electrified semi-trailer here utilizes an electric drive unit to assist the internal combustion engine main drive unit of the tractor to which the semi-trailer is connected.

[0068] The cooling system 10 includes a battery cell 5', an on-board charger 14 for charging the battery cell 5' using externally supplied electrical energy, and an electric drive unit 5 driven or drivable by the electrical energy of the battery cell 5'. To charge the battery cell 5', a charging plug compatible with the on-board charger 14 can be inserted.

[0069] The electric drive unit 5 has a dual drive system, consisting of two electric motors 12 and two associated inverters 12'. Furthermore, the electric drive unit 5 has a DC-DC converter 13. The electric motors 12 drive one axle of the semi-trailer or, in generator mode, brake the electrified semi-trailer.

[0070] Battery cell 5' includes three high-voltage battery strings 15, each of which includes three drive battery packs. Coolant from the cooling system flows through these battery packs and cools them.

[0071] The cooling system 10 includes a main cooling circuit 2 for cooling the coolant in the electric drive unit 5 and the on-board charger 14. The cooling system 10 also includes a secondary cooling circuit 4 for cooling the battery unit 5'. The main cooling circuit 2 has a first-loop pump assembly 7 and a heat exchanger 17 and a fan 18 configured as a radiator-fan unit, through which the heat absorbed by the coolant during cooling is dissipated to the external environment. The main cooling circuit 2 can be configured as either indirect or passive, wherein the first-loop pump assembly 7 is a coolant pump assembly.

[0072] The secondary cooling circuit 4 includes a second-loop pump unit 7', three heat exchangers 16, and a refrigeration unit 19. The three heat exchangers 16 are plate-shaped. The refrigeration unit 19 integrates a PTC heating element for preheating or pre-treating the battery cell 5' in charging mode. When the ambient temperature of the cooling system is below 0°C before initiating the required charging mode for the battery cell 5', the battery cell 5' can be heated to an operating temperature above 0°C via the PTC heating element in the secondary cooling circuit 4.

[0073] The second circuit pump unit 7' of the secondary cooling circuit 4 is a heat pump unit that is pre-installed on commercial vehicles. This heat pump unit circulates the coolant in the coolant passage of the secondary cooling circuit 4.

[0074] In contrast to the primary cooling circuit 2, the secondary cooling circuit 4 is active. The refrigeration unit 19 is constructed as a compression refrigeration unit, and the energy stored in the coolant is released into the environment through a heat exchanger within the refrigeration unit. In the secondary cooling circuit 4, this occurs by the refrigeration unit 19 through the targeted induction of a phase change in the coolant from a gaseous to a liquid state.

[0075] In the secondary cooling circuit 4, a heat exchanger 16 is arranged for each of the three high-voltage battery strings 15 of the battery unit 5'. Two distribution elements 11 are provided in the secondary cooling circuit 4, which are connected to the third and fourth multi-way valves 23 and 24 through coolant channels on the one hand, and to the three heat exchangers 16 through three branch coolant channels on the other hand.

[0076] In addition, the cooling system 10 includes four switchable 3 / 2-way valves 21, 22, 23, and 24 for regulating the coolant flow in the two cooling circuits 2 and 4. The main cooling circuit 2 includes first and second 3 / 2-way valves 21 and 22, while the secondary cooling circuit 4 has third and fourth 3 / 2-way valves 23 and 24.

[0077] Cooling circuits 2 and 4 are interconnected or separated via four 3 / 2-way valves 21, 22, 23, and 24 in this manner: to cool the electric drive unit 5 and the battery unit 5', they can selectively operate independently and in isolation, or operate in combination, depending on different operating modes. Cooling circuits 2 and 4, as well as the 3 / 2-way valves 21, 22, 23, and 24, are controlled and switched via a common control unit.

[0078] It is evident that all individual components of the electric drive unit 5 and the on-board charger 14 are arranged and connected in parallel with the heat exchanger 17 and fan 18 of the main cooling circuit 2 or with the radiator-fan unit.

[0079] The second multi-way valve 22 of the main cooling circuit 2 can selectively connect the on-board charger 14 and the electric drive unit 5 in parallel to the main cooling circuit 2, while the first multi-way valve 21 can selectively connect the main cooling circuit 2 to the secondary cooling circuit 4.

[0080] For this purpose, the main cooling circuit 2 has at least two parallel coolant channels 8 that can be connected to the secondary cooling circuit 4, wherein these two coolant channels 8 are arranged after the first circuit pump unit 7 of the main cooling circuit 2.

[0081] The first of the two coolant channels 8 can be connected to the main cooling circuit 2 via the first multi-way valve 21, and can selectively guide coolant from the main cooling circuit 2 to the secondary cooling circuit 4.

[0082] The second channel of the two coolant channels 8 is connected to the main cooling circuit 2 via a T-shaped element, and can selectively allow coolant to flow back from the secondary cooling circuit 4 to the main cooling circuit 2.

[0083] The second coolant passage 8 also has a one-way valve 6, wherein the main cooling circuit 2 includes other one-way valves that can be activated as needed to achieve on-demand cooling of the electric drive unit 5 and the battery unit 5'. The coolant passage 8 is connected to the refrigeration equipment 19 on one hand and to the three heat exchangers 16 of the secondary cooling circuit 4 on the other hand via the third and fourth multi-way valves 23 and 24.

[0084] Each of the three battery strings 15 has an additional distribution element 11 on its coolant supply side and discharge side (input side and output side). The distribution element 11 of the battery string 15 is connected to the second loop pump device 7' and the heat exchanger 16 through a coolant channel, respectively, and has three branch coolant channels to connect to the battery string 15.

[0085] The main cooling circuit 2 has a flow sensor 3 at each coolant channel of a component of the electric drive unit 5. The first and second circuit pump units 7, 7' are symbolically represented here as compressors. Coolant is delivered through the circuit pump units 7, 7' along a first flow direction S to the components to be cooled in the electric drive unit 5 and battery unit 5', and is then guided back from these components along a second flow direction S' towards the heat exchanger 17 or refrigeration unit 19, where the heat absorbed during the cooling process is dissipated to the external environment. A second circuit pump unit 7' or a compressor of a heat pump unit is provided on the coolant supply side for each battery string 15, aligned and functioning along the first flow direction S.

[0086] The two cooling circuits 2 and 4 also have multiple pressure sensors 3' for measuring pressure in the coolant passages through which they flow. For this purpose, the main cooling circuit 2 is equipped with a pressure sensor 3' near the compressor of each of the two first circuit pump units 7 shown in the figure, wherein the first pressure sensor 3' is arranged on the coolant supply side at the output side of the first compressor, and the second pressure sensor 3' is arranged on the coolant discharge side at the input side of the second compressor of the first circuit pump unit 7.

[0087] In the secondary cooling circuit 4, the three compressors of the three battery strings 15 shown in the figure are equipped with pressure sensors 3' on both the input and output sides, and other pressure sensors 3' are arranged between the third and fourth 3 / 2-way valves 23 and 24 and the refrigeration unit 19.

[0088] The main cooling circuit 2 also includes a compensation tank 9 or expansion tank, wherein the compensation tank 9 is connected in parallel with the heat exchanger 17 and is arranged between the first loop pump unit 7 and the heat exchanger 17 of the main cooling circuit 2. The secondary cooling circuit 4 specifies an additional compensation tank 9 for each of the three battery strings 15, wherein the compensation tank 9 of the secondary cooling circuit 4 is arranged between the battery cells 5' (i.e., the three battery strings 15 and six distribution elements 11 arranged on the input and output sides) and the second loop pump unit 7'.

[0089] Each of the three battery strings 15 forms an internal sub-loop with its assigned heat exchanger 16 within the secondary cooling loop 4, thereby allowing the compensation tank 9 to be simultaneously arranged between the coolant supply channel and the coolant discharge channel of the sub-loop of the battery string 15.

[0090] The cooling system has an emergency circuit 20 for emergency operation, which forms a sub-circuit of the main cooling circuit. The emergency circuit 20 has at least one compressor and two one-way valves 6, which open during emergency operation, or are switched in a manner that ensures that the required components or circulating coolant can still be safely cooled during emergency operation.

[0091] The coolant used in the cooling system 10 and flowing through the main cooling circuit and the secondary cooling circuits 2 and 4 is a water-ethylene glycol mixture, wherein the composition of the coolant mixture enables it to be used to cool the various components in both the main cooling circuit and the secondary cooling circuits 2 and 4.

[0092] The cooling regulation of the electric drive unit 5 and battery unit 5', as well as the switching of the 3 / 2-way valves 21, 22, 23, and 24 of the main cooling circuit and secondary cooling circuits 2 and 4, are based on the ambient temperature and the operating status of battery unit 5'. When the electric drive unit 5 is running and driving through the motor, battery unit 5' operates in discharge mode. When the on-board charger 14 is connected or the electric drive unit 5 is braking in generator mode, battery unit 5' operates in charging mode.

[0093] Figure 1 The first operating mode of the cooling system 10 is schematically illustrated. In this first operating mode, the ambient temperature is at least 15°C and the battery cell 5' is operating in discharge mode. The semi-trailer equipped with the cooling system 10 is in motion and is driven by the electric motor 12 of the electric drive unit 5. During this process, the drive battery pack of the battery string 15 is discharged.

[0094] The switching mode of the 3 / 2-way valves 21, 22, 23, and 24 allows the main cooling circuit 2 and the secondary cooling circuit 4 to operate independently and in isolation from each other. The main cooling circuit 2 flows through all the individual components of the electric drive unit 5 and the heat exchanger 17 during cooling, while the secondary cooling circuit 4 flows through the refrigeration device 19, the distribution element 11, the heat exchanger 16, and the battery unit 5' during cooling.

[0095] The first 3 / 2-way valve 21 and the second 3 / 2-way valve 22 close the parallel coolant passages leading to the secondary cooling circuit 4 and the on-board charger 14, thereby allowing the coolant to flow through the main cooling circuit 2 in a closed loop or circulate within the main cooling circuit 2.

[0096] The third 3 / 2-way valve 23 and the fourth 3 / 2-way valve 24 also close the channel connection from the coolant passage 8 to the main cooling circuit 2 on the secondary cooling circuit 4 side, thereby making the coolant circulate only in the secondary cooling circuit 4 and isolating the two cooling circuits 2 and 4.

[0097] Figure 2 The second operating mode of the cooling system 10 is explained. In the second operating mode, the ambient temperature is below 15°C and the battery cell 5' operates in discharge mode. Similar to the first operating mode, the semi-trailer equipped with the cooling system 10 is driven by the motor 12 of the electric drive unit 5, and the drive battery pack of the battery string 15 is discharged.

[0098] The switching modes of the 3 / 2-way valves 21, 22, 23, and 24 enable the main cooling circuit 2 and the secondary cooling circuit 4 to operate in a combined and connected manner. During cooling, the combined and connected cooling circuits 2 and 4 flow through all individual components of the electric drive unit 5 and the heat exchanger 17 of the main cooling circuit 2, as well as through the distribution element 11, heat exchanger 16, and battery unit 5' of the secondary cooling circuit 4. In the second operating mode, refrigerant does not flow through the refrigeration unit 19.

[0099] The first 3 / 2-way valve 21 opens the first parallel coolant passage 8 leading to the secondary cooling circuit 4, and simultaneously closes the coolant passage in the first flow direction S. Coolant flows into and through the secondary cooling circuit 4, and is then guided back to the main cooling circuit 2 through the second coolant passage 8. The second 3 / 2-way valve 22 switches in a similar manner to the first operating mode, but switches out a bypass to bypass the parallel coolant passage of the on-board charger 14.

[0100] The third 3 / 2-way valve 23 and the fourth 3 / 2-way valve 24 close the channel connection to the refrigeration equipment 19 on the secondary cooling circuit 4 side, and at the same time open the coolant channel to the distributor 11 and the main cooling circuit 2 through the coolant channel 8, so that the coolant circulates in the first cooling circuit and the secondary cooling circuits 2 and 4 (i.e., the main cooling circuit and the secondary cooling circuit), and the two cooling circuits 2 and 4 operate in combination.

[0101] Figure 3 A third operating mode is involved for the cooling system 10. In this third operating mode, the ambient temperature is at least 20°C and the battery cell 5' operates in charging mode. Under these conditions, the semi-trailer equipped with the cooling system 10 is charged at a suitable charging station via the onboard charger 14.

[0102] Here, the switching mode of the 3 / 2-way valves 21, 22, 23, and 24 allows the main cooling circuit and the secondary cooling circuits 2 and 4 to operate independently and in isolation. When cooling, the main cooling circuit 2 flows only through the on-board charger 14 and the heat exchanger 17, while the secondary cooling circuit 4 flows through the refrigeration device 19, the distribution element 11, the heat exchanger 16, and the battery cell 5'.

[0103] The first 3 / 2-way valve 21, similar to the first operating mode, closes the parallel coolant passage 8 leading to the secondary cooling circuit 4. In contrast, the second 3 / 2-way valve 22 opens the parallel coolant passage leading to the on-board charger 14 and simultaneously closes the extending coolant passage in the first flow direction S, preventing coolant from reaching the electric drive unit 5. A one-way valve 6 is also provided for this purpose, allowing this sub-circuit of the on-board charger 14 to connect to and isolate the electric drive unit 5, as it performs a similar blocking function on the coolant discharge side as the second coolant supply side 3 / 2-way valve 22.

[0104] The third 3 / 2-way valve 23 and the fourth 3 / 2-way valve 24 also close the channel connection from the coolant passage 8 to the main cooling circuit 2 on the secondary cooling circuit 4 side, so that the coolant circulates only in the secondary cooling circuit 4, similar to the first operating mode, and the two cooling circuits 2 and 4 are isolated.

[0105] Figure 4 The fourth operating mode of the cooling system 10 is demonstrated. In this mode, the ambient temperature is below 20°C and the battery cell 5' operates in charging mode. Under these conditions, the semi-trailer equipped with the cooling system 10 is charged at a suitable charging station via the onboard charger 14.

[0106] The switching mode of the 3 / 2-way valves 21, 22, 23, and 24 allows the main cooling circuit and the secondary cooling circuits 2 and 4 to operate in a combined and connected manner. During cooling, the combined and connected cooling circuits 2 and 4 flow through the on-board charger 14 and the heat exchanger 17, while the secondary cooling circuit 4 flows through the distribution element 11, the heat exchanger 16, and the battery cell 5' during cooling. Similar to the second operating mode, in the fourth operating mode, the refrigerant does not flow through the refrigeration unit 19.

[0107] The first 3 / 2-way valve 21 opens the first parallel coolant passage 8 leading to the secondary cooling circuit 4, and similarly to the second operating mode, closes the coolant passage extending further along the pipeline in the first flow direction S. Coolant thus flows into and through the secondary cooling circuit 4, and is then guided back to the main cooling circuit 2 through the second coolant passage 8. The second 3 / 2-way valve 22 switches in a similar manner to the third operating mode, meaning it opens the parallel coolant passage leading to the on-board charger 14, and simultaneously closes the coolant passage extending further along the first flow direction S, thus preventing coolant from reaching the electric drive unit 5 even in the fourth operating mode.

[0108] Similar to the second operating mode, the third 3 / 2-way valve 23 and the fourth 3 / 2-way valve 24 close the channel connection to the refrigeration equipment 19 on the secondary cooling circuit 4 side, and at the same time open the coolant channel to the distributor 11 and the main cooling circuit 2 through the coolant channel 8, so that the coolant circulates in the first cooling circuit and the secondary cooling circuits 2 and 4 (i.e., the main cooling circuit and the secondary cooling circuit), and the two cooling circuits 2 and 4 operate in combination.

[0109] This invention is not limited to the above embodiments, but can be modified in various ways. Overall, this dynamic intelligent cooling system and the multi-way valve device of this invention are suitable for modern battery electric vehicles.

[0110] In particular, this cooling system can be used in electrified semi-trailers driven by high-performance motors and high-voltage batteries. Other trailer types and tractor combinations can also be temperature-controlled using the cooling system of this invention. Specific arrangements and dimensions can vary, provided that the described switching positions, flow loops, and functionality are followed.

[0111] All features and advantages derived from the claims, description and drawings, including structural details, spatial arrangement and method steps, whether viewed individually or in various combinations, constitute the essence of the invention.

[0112] List of reference numerals

[0113] S is the first flow direction (coolant supply).

[0114] S' Second flow direction (coolant recirculation)

[0115] 2. Main cooling circuit (passive)

[0116] 3 Flow Sensor

[0117] 3' Pressure sensor

[0118] 4. Secondary cooling circuit (active)

[0119] 5 Electric drive units

[0120] 5' battery cell

[0121] 6. Check valve

[0122] 7. First circuit pump unit (main cooling circuit)

[0123] 7' Secondary circuit pump unit (secondary cooling circuit)

[0124] 8. First and second coolant passages

[0125] 9. Expansion Tank (Compensation Tank)

[0126] 10. Cooling System (High-Voltage Battery Cooling System)

[0127] 11. Distribution element (shunt)

[0128] 12 Electric motors

[0129] 12' Inverter

[0130] 13 DC-DC voltage converter

[0131] 14. On-board charger (OBC)

[0132] 15 High-voltage battery strings (each containing three drive battery packs)

[0133] 16. Heat exchanger (secondary cooling circuit)

[0134] 17. Heat exchanger (main cooling circuit)

[0135] 18 Fans (Radiator - Fan Unit)

[0136] 19 Refrigeration equipment (compression refrigeration units)

[0137] 20 Emergency Circuit (Sub-circuit)

[0138] 21 First multi-way valve (3 / 2-way valve)

[0139] 22 Second multi-way valve (3 / 2-way valve)

[0140] 23. Third multi-way valve (3 / 2-way valve)

[0141] 24. Fourth multi-way valve (3 / 2-way valve)

Claims

1. A cooling system (10), particularly a high-voltage battery cooling system for commercial vehicles, the cooling system comprising a battery cell (5'), an on-board charger (14) for charging the battery cell (5') using externally supplied electrical energy, and an electric drive unit (5) driven by the electrical energy of the battery cell (5'), wherein, The cooling system has a main cooling circuit (2) for cooling the electric drive unit (5) and the on-board charger (14), and a secondary cooling circuit (4) for cooling the battery cell (5'). The main cooling circuit (2) includes a first-loop pump (7), a heat exchanger (17), and a fan (18). The secondary cooling circuit (4) includes a second-loop pump (7'), at least one heat exchanger (16), and a refrigeration device (19). The cooling system is characterized by including multiple switchable multi-way valves (21, 22, 23, 24) for regulating the coolant flow rate in the cooling circuits (2, 4). The cooling circuits (2, 4) can be interconnected or separated from each other via the multi-way valves (21, 22, 23, 24) to cool the electric drive unit (5) and the battery cell (5'). 4) They can operate independently and in isolation, or be combined and connected together.

2. The cooling system according to claim 1, characterized in that, At least four multi-way valves (21, 22, 23, 24) are provided, wherein the main cooling circuit (2) includes a first multi-way valve (21) and a second multi-way valve (22), and wherein the secondary cooling circuit (4) includes a third multi-way valve (23) and a fourth multi-way valve (24).

3. The cooling system according to claim 2, characterized in that, The second multi-way valve (22) selectively connects the on-board charger (14) and the electric drive unit (5) in parallel to the main cooling circuit (2), wherein the first multi-way valve (21) selectively connects the main cooling circuit (2) to the secondary cooling circuit (4).

4. The cooling system according to any one of the preceding claims, characterized in that, The multi-way valves (21, 22, 23, 24) are configured as 3 / 2-way valves, wherein the multi-way valves (21, 22, 23, 24) can be controlled and switched through a common control unit.

5. The cooling system according to any one of the preceding claims, characterized in that, The electric drive unit (5) has a dual drive device, which includes two motors (12) and an associated inverter (12'), wherein the electric drive unit (5) has at least one DC voltage converter (13).

6. The cooling system according to any one of the preceding claims, characterized in that, All individual components of the electric drive unit (5) and the on-board charger (14) are arranged and connected in parallel with the heat exchanger (17) and the fan (18) of the main cooling circuit (2).

7. The cooling system according to any one of the preceding claims, characterized in that, The main cooling circuit (2) can be connected to the secondary cooling circuit (4) through at least two parallel coolant channels (8), wherein the two coolant channels (8) are arranged after the first circuit pump device (7) of the main cooling circuit (2).

8. The cooling system according to claim 7, characterized in that, One of the two coolant channels (8) can be connected to the main cooling circuit (2) via the first multi-way valve (21), while the other of the two coolant channels (8) is connected to the main cooling circuit (2) via a T-shaped element.

9. The cooling system according to claim 7 or 8, characterized in that, The coolant channel (8) can be connected to the refrigeration equipment (19) through the third multi-way valve (23) and the fourth multi-way valve (24), and can also be connected to at least one heat exchanger (16) of the secondary cooling circuit (4).

10. The cooling system according to any one of the preceding claims, characterized in that, The battery cell (5') has three high-voltage battery strings (15), each of which includes three drive battery packs. The coolant of the cooling system flows through the drive battery packs and cools them.

11. The cooling system according to claim 10, characterized in that, In the secondary cooling circuit (4), a heat exchanger (16) is arranged for each of the three high-voltage battery strings (15). In the secondary cooling circuit (4), two distribution elements (11) are provided. The distribution elements (11) are connected to the third multi-way valve (23) and the fourth multi-way valve (24) through a coolant channel on the one hand, and to the three heat exchangers (16) through three branch coolant channels on the other hand.

12. The cooling system according to claim 10 or 11, characterized in that, Each battery string (15) has an additional distribution element (11) on its coolant supply side and discharge side, wherein the distribution element (11) of the battery string (15) is connected to the second loop pump device (7') and the heat exchanger (16) respectively through a coolant channel, and has three branch coolant channels to connect to the battery string (15).

13. The cooling system according to any one of the preceding claims, characterized in that, The coolant is a water-ethylene glycol mixture, wherein the composition of the coolant mixture is such that it can be used to cool the various components in both the main cooling circuit (2) and the secondary cooling circuit (4).

14. The cooling system according to any one of the preceding claims, characterized in that, The cooling regulation of the electric drive unit (5) and the battery unit (5') and the switching of the multi-way valves (21, 22, 23, 24) of the main cooling circuit (2) and the secondary cooling circuit (4) are performed according to the ambient temperature and the operating status of the battery unit (5'). When the electric drive unit (5) is in driving mode, the battery unit (5') operates in discharge mode, and when the on-board charger (14) is connected or the electric drive unit (5) is in braking mode, the battery unit (5') operates in charging mode.

15. The cooling system according to claim 14, characterized in that, In the first operating mode, i.e., when the ambient temperature is at least 15°C and the battery cell (5') is operating in the discharge mode, the switching mode of the multi-way valves (21, 22, 23, 24) enables the main cooling circuit (2) and the secondary cooling circuit (4) to operate independently and in isolation from each other. The main cooling circuit (2) flows through all individual components of the electric drive unit (5) and through the heat exchanger (17) during cooling, and the secondary cooling circuit (4) flows through the refrigeration device (19), the distribution element (11), the heat exchanger (16), and the battery cell (5') during cooling.

16. The cooling system according to claim 14, characterized in that, In the second operating mode, i.e., when the ambient temperature is below 15°C and the battery cell (5') is operating in the discharge mode, the switching mode of the multi-way valves (21, 22, 23, 24) causes the main cooling circuit (2) and the secondary cooling circuit (4) to operate in combination. The combined cooling circuits (2, 4) flow through all individual components of the electric drive unit (5) and the heat exchanger (17) of the main cooling circuit (2) during cooling, and also flow through the distribution element (11), the heat exchanger (16), and the battery cell (5') of the secondary cooling circuit (4).

17. The cooling system according to claim 14, characterized in that, In the third operating mode, i.e., when the ambient temperature is at least 20°C and the battery cell (5') is operating in the charging mode, the switching mode of the multi-way valves (21, 22, 23, 24) enables the main cooling circuit (2) and the secondary cooling circuit (4) to operate independently and in isolation from each other. The main cooling circuit (2) flows through the on-board charger (14) and the heat exchanger (17) when cooling, and the secondary cooling circuit (4) flows through the refrigeration device (19), the distribution element (11), the heat exchanger (16), and the battery cell (5') when cooling.

18. The cooling system according to claim 14, characterized in that, In the fourth operating mode, i.e., when the ambient temperature is below 20°C and the battery cell (5') is operating in the charging mode, the switching mode of the multi-way valves (21, 22, 23, 24) causes the main cooling circuit (2) and the secondary cooling circuit (4) to operate in combination. The combined cooling circuit (2, 4) flows through the on-board charger (14) and the heat exchanger (17) of the main cooling circuit (2) during cooling, and flows through the distribution element (11), the heat exchanger (16) and the battery cell (5') of the secondary cooling circuit (4).

19. The cooling system according to any one of claims 14 to 18, characterized in that, The second multi-way valve (22) of the main cooling circuit is switched in the discharge mode of the battery cell (5') to form a bypass circuit for the on-board charger (14) and to prevent the coolant from flowing to the coolant channel of the on-board charger (14).

20. The cooling system according to any one of claims 14 to 18, characterized in that, The second multi-way valve (22) and the additional one-way valve (6) of the main cooling circuit (2) are connected in the charging mode of the battery cell (5') such that the electric drive unit (5) is isolated from the main cooling circuit (2) and no coolant flows through it.

21. The cooling system according to any one of the preceding claims, characterized in that, The refrigeration device (19) includes a PTC heating element for pre-treating the battery cell (5'), wherein when the ambient temperature of the cooling system is below 0°C before the charging mode for the battery cell (5') is started, the battery cell (5') can be heated to an operating temperature above 0°C by the PTC heating element in the secondary cooling circuit (4).

22. A method for operating a cooling system (10) according to any one of the preceding claims.

23. A commercial vehicle having a cooling system (10) according to any one of claims 1 to 21, characterized in that, The commercial vehicle is composed of a tractor and a trailer connected to the tractor, the trailer having at least one, preferably three, trailer axles, wherein the trailer has the electric drive unit (5) and the battery unit (5'), and wherein the cooling system (10) is provided on the electrified trailer.

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