Charging of electric vehicles and construction machines

Abstract

A method for managing a state of charge of a battery of an electrically powered work vehicle, the battery being ready to return to work at a return to work time coinciding with an end of a fixed duration. A charging mode is selected through a user interface. An initial state of charge of the battery and a target operating state of charge of the battery are used to calculate a target charge increment. A charging cycle comprising a charging rate is selected based on the charging mode and the target charge increment. A charging start time is calculated such that at the return to work time, an actual state of charge of the battery corresponds to the target operating state of charge. At the charging start time, a temperature of the battery is adjusted to a target temperature. The charging cycle is started at the charging start time.

Description

Technical Field

[0001] This invention relates to the field of charging electric vehicles or construction machinery. Background Technology

[0002] Electric vehicles or construction machinery may include a battery inside the electric vehicle that is charged using electricity from an external vehicle charging device. Traditionally, many electric vehicles are configured for fast charging by default, assuming the operator wants the vehicle ready for use as soon as possible. The battery is then kept at a high charge until it is used.

[0003] Battery health depends on several factors, including the rate of charge, the state of charge during storage, and the temperature during charging. Fast charging can increase battery aging, for example, due to thermal shock. Many batteries only experience a limited number of fast-charge cycles before performance degradation occurs to the point of limiting battery capacity below acceptable levels. Storing batteries in a high-charge state also increases battery aging.

[0004] It is known to provide users with the ability to select a charging mode based on information about electricity costs (US8,716,978B2). The lowest electricity cost can be determined based on a predetermined period of time for charging, and users can choose whether to continue with fast charging or wait to charge the vehicle during the charging period with the lowest cost.

[0005] A known charging management system stores the battery in a low-charge state and charges it just before the electric vehicle is needed, rather than charging it immediately and storing it in a high-charge state (EP2398670A1). The charging is planned using a fixed duration for the vehicle and the time required to fully charge the battery from its initial state, such that the battery remains in a low-charge state in storage for as long as possible and reaches its maximum charge level just before the vehicle is used.

[0006] Storing batteries in a low state of charge is important for long-term battery health; however, using a lower charging rate is also preferred. This may be particularly useful in the case of electric vehicles with long, known fixed cycles, where managing charging to maintain a low state of charge and a low charging rate can be beneficial. The charging rate can be determined by the length of the fixed cycle.

[0007] Small, off-road electrified construction machinery can typically operate within a predictable timeframe. For example, such electric work vehicles might be expected to work in shifts, five days a week, and not be used overnight or on weekends. They can also be stored for extended periods. Summary of the Invention

[0008] In view of this background, a method is provided for managing the state of charge of a battery in an electric work vehicle, the battery being prepared to return to work at a return-to-work time coinciding with the end of a fixed duration, the method comprising:

[0009] a. Select the charging mode via input from the user interface and obtain data indicating the charging mode from the output of the user interface;

[0010] b. Calculate the target charge increment using the initial state of charge value of the battery and the target operating state of charge value of the battery;

[0011] c. Selecting a charging cycle based on the charging mode and the target charging increment, wherein the charging cycle includes a charging rate;

[0012] d. Calculate the charging start time based on the charging rate and the target charging increment, such that at the return working time, the actual charging state of the battery corresponds to the target operating charging state value;

[0013] e. Calculate the target temperature change using the initial temperature of the battery and the target temperature of the battery;

[0014] f. Use the target temperature change to calculate the heat exchange start time, such that the battery is at the target temperature before the charging start time;

[0015] g. Adjusting the temperature of the battery at the start time of heat exchange so that the battery is at the target temperature at the start time of charging; and

[0016] h. Start the charging cycle at the charging start time, so that the battery is in the target operating charging state when returning to the working time.

[0017] In this way, it's possible to manage the charging of electric work vehicles by combining long-term battery health considerations with return-to-work requirements. Scheduling charging in this manner allows the battery to be preheated before charging begins to prevent thermal shock and extend battery life. The battery can be stored in a low-charge state, and the charging rate can be selected to be slower when the vehicle is not needed, which slows battery degradation. Other return-to-work preparations can also be made. For example, work vehicles typically have hydraulic circuits for operating work tools. Cold, viscous hydraulic fluid can lead to parasitic losses, which can reduce charging efficiency. It may be advantageous to preheat the hydraulic fluid before the vehicle is ready to return to work, which can be scheduled based on a charging plan.

[0018] In a second aspect, a battery charging controller is provided that manages the state of charge of the battery of an electric work vehicle preparing to return to work at a return-to-work time that coincides with the end of a fixed duration, the battery charging controller being configured to:

[0019] a. Receive first data including the initial state of charge value of the battery;

[0020] b. Receive second data from the user interface, wherein the second data indicates the charging mode;

[0021] c. Receive third data including the initial temperature of the battery;

[0022] d. Calculate the target charge increment using the first data and the target operating state of the battery;

[0023] e. Select a charging cycle based on the second data and the target charging increment, wherein the charging cycle includes a charging rate;

[0024] f. Calculate the charging start time based on the charging rate and the target charging increment, such that at the return working time, the actual charging state of the battery is the target operating charging state value;

[0025] g. Calculate the target temperature change using the third data and the target temperature of the battery;

[0026] h. Use the target temperature change to calculate the heat exchange start time, such that the battery is at the target temperature before the charging start time;

[0027] i. Adjust the temperature of the battery at the start time of heat exchange so that the battery is at the target temperature at the start time of charging; and

[0028] j. Start the charging cycle at the charging start time so that the battery is in the target operating charging state when it returns to the working time. Attached Figure Description

[0029] Specific embodiments of the invention will now be described by way of example only with reference to the accompanying drawings, in which:

[0030] Figure 1 A process for selecting a charging cycle and managing the state of charge of a battery according to an embodiment of the present invention is shown.

[0031] Figure 2 The present invention illustrates a process for selecting a charging cycle, managing the state of charge of a battery, and heating the hydraulic fluid according to an embodiment of the invention.

[0032] Figure 3A process for selecting a charging cycle and managing the state of charge of a battery according to an embodiment of the present invention is shown, wherein the battery may be stored in a storage state of charge.

[0033] Figure 4 A process for selecting a charging cycle and managing the state of charge of a battery according to an embodiment of the present invention is shown, wherein the battery can be charged when a target charge increment is higher than a threshold.

[0034] Figure 5 A process for selecting a charging cycle and managing the state of charge of a battery according to an embodiment of the present invention is shown, wherein the battery can be stored in a stored charging state and can be charged if the target charging increment is higher than a threshold. Detailed Implementation

[0035] According to an embodiment of the present invention, a method is provided for managing the state of charge of a battery in an electric work vehicle in preparation for returning to work at a return-to-work time that coincides with the end of a fixed duration. The battery of the electric work vehicle may be connected to an external charging device. A controller may be used to manage the state of charge of the battery.

[0036] refer to Figure 1 Various data inputs can be used to determine charging cycles and calculate charging plans. Users can select charging mode 121 via input from the user interface. If the selected charging mode is not a long-term storage mode, charging mode 121 can correspond to a predetermined fixed duration. The steps that may be involved in determining the charging cycle and plan are shown within dashed lines 100. In step 110, the initial state-of-charge value 111 and the target state-of-charge value 112 of the battery are used to calculate the target charging increment. In step 120, the charging cycle is selected using charging mode 121 and the calculated target charging increment, where the charging cycle includes a charging rate. A charging rate can be selected such that the time spent charging the battery is less than the vehicle's fixed expected duration. The charging rate can be constant or can vary over time. At step 130, the charging rate and the target charging increment are used to calculate how long it will take to charge the battery from the initial state-of-charge value to the target state-of-charge value. Then, the charging start time t is calculated using the desired braking duration. C This ensures that the battery's state of charge (SOC) value is equal to or higher than the target SOC value at the time of return to operating time. In step 140, the initial temperature of battery 141 and the target temperature 142 of the battery can be used to calculate the target temperature change. The target temperature change can be used to calculate the time required to cool or heat the battery from the initial temperature to the target temperature 142. Then, the start time t of the heat exchange process can be calculated in step 150. T This allows the battery to start charging at time t. CThe target temperature of 142°C is reached at or before the start of heat exchange. T The heat exchange process begins (step 160). At the start of charging time t... C The battery is at the target temperature, and charging begins at the charging rate associated with the selected charging cycle (step 170). In step 180, the vehicle is then ready to return to operation at the end of the expected fixed duration with a state of charge value equal to the target state of charge value 112.

[0037] The user interface provides at least one selectable charging mode 121, wherein the charging mode 121 may correspond to a fixed duration of the work vehicle. In one embodiment, the user can select from a predetermined list of selectable charging modes 121, such as fast charging, periodic charging, overnight, weekend, or long-term storage. In a particular embodiment, the overnight mode may correspond to a fixed duration of, for example, 12 hours, and the weekend mode may correspond to a fixed duration of, for example, 60 hours.

[0038] In step 120, a charging cycle is selected based on the target charging increment and the desired fixed duration. The charging cycle can be selected from a pre-programmed list of charging cycles. In one embodiment, the pre-programmed list of charging cycles may include one or more charging cycles for each optional charging mode 121. Each optional charging mode 121 may include different charging rates. In one embodiment, a charging rate slower than that used for fast charging may be selected. In a particular embodiment, a charging cycle may be selected with the slowest charging rate, for which the battery can still be charged to a state of charge value equal to the target state of charge value at the end of the fixed duration at the return-to-work time.

[0039] refer to Figure 2 The embodiments described herein may include an additional step 220 of heating the hydraulic fluid. The work vehicle may include a hydraulic circuit for moving machine tools. Viscous hydraulic fluid causes additional power loss, therefore heating the hydraulic fluid to reduce its viscosity before the vehicle returns to work increases charging efficiency. Heating the hydraulic fluid may be performed such that the hydraulic fluid is at a target operating temperature when the vehicle returns to work. In embodiments of the invention, heating the hydraulic fluid may occur during battery charging using power from an external charging device. In one embodiment, heating the hydraulic fluid may occur if certain charging modes 121 suitable for heating the hydraulic fluid are selected. The charging mode 121 suitable for heating the hydraulic fluid will correspond to a fixed duration and will therefore indicate the return to work time, such as a quick, overnight, or weekend mode. In step 210, if charging mode 121 is suitable for heating the hydraulic fluid, then heating the hydraulic fluid occurs in step 220.

[0040] See Figure 3 In the embodiment shown, if the selected charging mode 121 is a long-term storage mode, there may be an additional arrangement to store the electric vehicle in a low-charge state. Storing the battery in a low-charge state may be preferred for long-term battery health; however, it may require additional charging cycles to charge or discharge to the storage state and then recharge it, which could be detrimental to long-term battery health. Therefore, there may be a minimum storage time for which the benefits of storing in a low-charge state outweigh the adverse effects of the additional charging cycles. In one embodiment, the battery is stored in a low-charge state only if the selected charging mode 121 is a long-term storage mode. If the selected charging mode 121 in step 310 is not a long-term storage mode, the charging process is similar to... Figure 1 or Figure 2 The process shown (refer to the same numbers and steps, such as...) Figure 1 (As shown). The initial state-of-charge value of the battery can be used to calculate the target charge increment, and the battery may be charged or not discharged until the start time t of charging. C If the charging mode 121 selected in step 310 is a long-term storage mode, the target charge increment can be calculated using the stored state of charge value 311 in step 110. After the charging cycle has been selected and the parameters have been calculated, in step 330, the battery can be discharged (or charged) to the stored state of charge value and held there. At step 340, the battery's state of charge value can be maintained at the stored state of charge value until the charging device is instructed to proceed in another manner. In a particular embodiment, the stored state of charge value can be between 40% and 50% of full capacity.

[0041] refer to Figure 4 If the initial state of charge is close to the target state of charge, charging the battery can be waived. In step 410, the calculated target charge increment can be compared with a charging threshold. If the target charge increment is lower than the charging threshold, charging is not performed. The battery or hydraulic fluid can be heated before the return-to-work time. In step 440, the initial temperature 441 and the target temperature 442 of the battery can be used to calculate the target temperature increment of the battery. The heat exchange start time t can then be calculated in step 450. T And it can be done at the start time t of heat exchange. T Adjust the temperature (step 460) so that the battery is at the target temperature when or before returning to operating time. If the target charge increment is higher than the charging threshold, it can be similar to... Figure 1 The charging process is performed as shown. In the steps and Figure 1 Where the steps are the same, use the same reference numerals.

[0042] Figure 3 and Figure 4 The processes shown can be combined such that if the target charge increment is below the charging threshold but the expected fixed duration is longer than the storage threshold, the battery can be discharged to the stored state of charge value, and this process follows... Figure 3 Continue. The process is as follows: Figure 5 As shown. When the selected charging mode 121 is long-term storage, in step 110, the target charge increment can be calculated using the stored state of charge value 311. When the selected charging mode 121 is not long-term storage, in step 110, the target charge increment is calculated using the battery's initial state of charge value 111. Then, in step 410, the target charge increment can be compared with a charging threshold.

[0043] When the target charging increment is greater than the charging threshold, the process can be similar to Figure 3 Proceed. Regarding... Figure 3 The same steps are followed, with the same reference numerals in the accompanying drawings. A charging cycle can be selected in step 120, and the charging start time can be calculated in step 130. The target temperature change can be calculated in step 140, and the heat exchange start time can be calculated in step 150. If the charging mode is not a long-term storage mode in step 320, the next step 160 can be at the heat exchange start time t. T Heat or cool the battery to the target temperature of 142°C. At the start of charging time t... C The battery can be at the target temperature 142 and begin charging at the charging rate until the state of charge value equals the target state of charge 112. Then, in step 180, the vehicle can prepare to return to work at the return-to-work time. If the charging mode 121 selected in step 320 is long-term storage, in step 330, the actual state of charge of the battery can be adjusted to equal the storage state of charge 311. In step 340, the battery can remain in the storage state of charge until the charging device receives further instructions.

[0044] If the target charge increment is less than the charging threshold in step 410, and the selected charging mode 121 in step 520 is for long-term storage, the battery can be stored in a charging state equal to the storage charging state. Therefore, by selecting a charging cycle in step 120, the process continues in the same manner as when the target charge increment is found to be greater than the charging threshold in step 410. If the selected charging mode 121 in step 520 is not for long-term storage, neither discharging nor charging can be performed, and only the temperature can be adjusted. The target temperature change can be calculated in step 540 using the initial temperature 541 and the target temperature 542, and the heat exchange start time t can be calculated in step 550. T At the start time t of heat exchange TThe temperature can be adjusted (step 560), and the vehicle is ready to return to work at the scheduled return time (step 180).

[0045] In some implementations, Figure 1 The methods shown in -5 can be combined in various ways.

[0046] In embodiments of the present invention, the battery temperature can be obtained by measuring the temperature of the battery fluid. The heat exchange process can utilize a liquid heat exchanger to heat or cool the battery fluid.

Claims

1. A method for managing the state of charge of a battery in an electric work vehicle in preparation for returning to work at a return-to-work time that coincides with the end of a fixed duration, wherein, The electric work vehicle includes a hydraulic circuit for moving the machine tool, and the method includes: a. Select a charging mode via input from the user interface and obtain data indicating the charging mode from the output of the user interface; b. Calculate the target charge increment using the initial state of charge value of the battery and the target operating state of charge value of the battery; c. Select a charging cycle based on the charging mode and the target charging increment, wherein the charging cycle includes a charging rate, the charging rate being the slowest charging rate that charges the battery to the target operating state of charge value at the end of a fixed duration. d. Calculate the charging start time based on the charging rate and the target charging increment, such that at the return working time, the actual charging state of the battery corresponds to the target operating charging state value; e. Calculate the target temperature change using the initial temperature of the battery and the target temperature of the battery; f. Use the target temperature change to calculate the heat exchange start time, such that the battery is at the target temperature before the charging start time; g. Adjusting the temperature of the battery at the start time of heat exchange so that the battery is at the target temperature at the start time of charging; h. Start the charging cycle at the charging start time, such that the battery is at the target operating state of charge value at the return working time; and i. During battery charging using power from an external charging device, the hydraulic fluid in the hydraulic circuit is heated such that the hydraulic fluid is at the target hydraulic fluid temperature at the return working time.

2. The method according to claim 1, wherein, When the selected charging mode is a long-term storage mode, the method includes using the stored charging state value as the initial charging state in step (b).

3. The method according to claim 2, wherein, The method includes adjusting the state of charge of the battery to the stored state of charge value after step (f).

4. The method according to claim 2 or 3, wherein, The storage charge state value is between 40% and 50%.

5. The method according to any one of claims 1-3, further comprising comparing the target charging increment with a charging threshold, wherein, If the target charging increment is less than the charging threshold, the target charging increment is zero.

6. The method according to claim 1, wherein, The method includes performing a service procedure before the return-to-work time.

7. The method according to claim 1, wherein, The method includes obtaining data indicating battery health.

8. The method according to claim 1, wherein, The charging start time may be based on external factors that vary over a predetermined fixed duration, wherein the external factors include one or more of the following: a. Electricity costs; and b. Ambient temperature.

9. A battery charging controller for managing the state of charge of a battery in an electric work vehicle, in preparation for returning to work at a return-to-work time that coincides with the end of a fixed duration, wherein, The electric work vehicle includes a hydraulic circuit for moving the machine's working tools, and wherein the battery charging controller is configured to: a. Receive first data including the initial state of charge value of the battery; b. Receive second data from the user interface, wherein the second data indicates the charging mode; c. Receive third data including the initial temperature of the battery; d. Calculate the target charge increment using the first data and the target operating state of charge value of the battery; e. Select a charging cycle based on the second data and the target charging increment, wherein the charging cycle includes a charging rate, the charging rate being the slowest charging rate that charges the battery to the target operating state of charge value at the end of a fixed duration. f. Calculate the charging start time based on the charging rate and the target charging increment, such that at the return working time, the actual charging state of the battery is the target operating charging state value; g. Calculate the target temperature change using the third data and the target temperature of the battery; h. Use the target temperature change to calculate the heat exchange start time, such that the battery is at the target temperature before the charging start time; i. Adjust the temperature of the battery at the start time of heat exchange so that the battery is at the target temperature at the start time of charging; j. Start the charging cycle at the charging start time, such that the battery is at the target operating state of charge value at the return working time; and k. During battery charging using power from an external charging device, the hydraulic fluid in the hydraulic circuit is heated so that the hydraulic fluid is at the target hydraulic fluid temperature at the return working time.

10. The battery charging controller of claim 9, configured to receive fourth data, wherein, The fourth data includes a stored state of charge value, and wherein, when the selected charging mode is a long-term storage mode, the battery charging controller is configured to use the stored state of charge value as the first data including the initial state of charge value.

11. The battery charging controller according to claim 10, wherein, The controller is configured to adjust the state of charge of the battery to the stored state of charge value after step (h).

12. The battery charging controller according to claim 10 or 11, wherein, The storage charge state value is between 40% and 50%.

13. The battery charging controller according to any one of claims 9-11, wherein, The controller is configured to compare the target charging increment with a charging threshold, and if the target charging increment is less than the charging threshold, the target charging increment is zero.

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