Battery management system and method for agricultural electric vehicle

Abstract

The present invention relates to a battery management system and method for an agricultural electric vehicle. According to the present invention, when charging a high-voltage battery, it is possible to check the voltage of a low-voltage battery, and activate or deactivate a voltage converter on the basis of the checked voltage value, thereby increasing the charging speed of the high-voltage battery.

Description

Battery management system and management method for agricultural electric vehicles

[0001] The present invention relates to a battery management technology for an agricultural electric vehicle.

[0002] Agricultural work vehicles are being developed and evolved for agricultural work.

[0003] Agricultural work vehicles include tractors, combines, and rice transplanters.

[0004] Recently, advances in battery technology have led to the development of electric agricultural vehicles.

[0005] Typically, agricultural electric vehicles have high-voltage and low-voltage batteries. For example, high-voltage batteries provide 350 V of power, while low-voltage batteries provide 12 V.

[0006] High-voltage batteries replace the internal combustion engines of the past. Therefore, high-voltage batteries are primarily used to secure power for power-hungry driving and agricultural tasks. For example, the power from high-voltage batteries is discharged by high-voltage electrical loads such as drive motors and hydraulic pumps. The discharged high-voltage batteries are then recharged using external power.

[0007] On the other hand, the power of low-voltage batteries is discharged by low-voltage electrical loads such as lights and various control devices. Therefore, low-voltage batteries also require charging.

[0008] Low-voltage batteries are charged using power from the high-voltage battery, not external power. To achieve this, a voltage converter is installed between the low-voltage and high-voltage batteries.

[0009] The voltage converter is called a low voltage DC-DC converter (LDC).

[0010] Voltage converters are used not only to charge low-voltage batteries, but also to power low-voltage electrical loads. Thus, in agricultural electric vehicles, low-voltage electrical loads can receive 12 V power from two sources.

[0011] The first path is from the low-voltage battery to the low-voltage electrical loads.

[0012] The second path is from the voltage converter to the low-voltage electrical loads.

[0013] Meanwhile, lead-acid batteries were used as low-voltage batteries for 12V in the past.

[0014] Lead-acid batteries have the advantage of being rechargeable even after over-discharge. However, they are heavy and have a low charge density. Lead acid, in particular, is a pollutant. Consequently, lithium-ion batteries are increasingly used as low-voltage 12V batteries. However, lithium-ion batteries have a critical weakness: they cannot be recharged after over-discharge.

[0015] Therefore, the first path is mainly selected when the ignition is OFF, and the second path is selected when the ignition is ON.

[0016] For example, the controller operates to supply the power required to turn the ignition on and off, as well as the power consumed by low-voltage electrical loads when the ignition is off, from the low-voltage battery. Of course, because the power consumption of low-voltage electrical loads is minimal when the ignition is off, there is very little risk of compromising the stability of the low-voltage battery.

[0017] When the engine is on and running, the discharge caused by low-voltage electrical loads is significant. Therefore, the controller operates to supply the low-voltage power consumed by these loads from the voltage converter. Because the voltage converter operates, the low-voltage battery can be continuously charged. This battery management method prevents overdischarge of the low-voltage battery and maintains its stability.

[0018] Currently, research and development of agricultural electric vehicles (EVs) is accelerating, in line with the trend toward eco-friendliness. Despite this, widespread adoption of EVs for agricultural use remains elusive. One of the many reasons for this slow adoption is the excessive charging time of the high-voltage batteries used in these vehicles. Slow charging, rather than rapid charging, requires charging times exceeding six hours. For this reason, various research projects are actively underway to increase the charging speed of agricultural EVs.

[0019] [Prior Art Literature]

[0020] [Patent Document]

[0021] (Patent Document 1) Republic of Korea Publication No. 10-2022-0073891

[0022] (Patent Document 2) Republic of Korea Publication No. 10-2018-0063571

[0023] (Patent Document 3) Republic of Korea Publication No. 10-2022-0117033

[0024] The present invention was conceived from consideration of battery management technology that can improve the charging speed in agricultural electric vehicles.

[0025] A battery management system for an agricultural electric vehicle according to a first aspect of the present invention comprises: a high-voltage battery that provides high-voltage power and is configured to be charged with external power; a low-voltage battery that provides low-voltage power lower than that of the high-voltage battery and is configured to be charged with the power of the high-voltage battery; a voltage converter that converts the power of the high-voltage battery into low voltage and supplies the power to the low-voltage battery and low-voltage electrical loads; and a controller that can control the voltage converter to be activated or deactivated by checking the voltage of the low-voltage battery.

[0026] The above controller can control the voltage converter to be deactivated when the voltage of the low-voltage battery is higher than a first set value in a charging mode in which the high-voltage battery is charged.

[0027] The above controller can control the low-voltage electric loads to operate by power from the low-voltage battery when the voltage converter is disabled in the charging mode.

[0028] The controller can control the low-voltage battery to be charged by activating the voltage converter when the voltage of the low-voltage battery is lower than a second set value that is lower than the first set value after deactivating the voltage converter in the charging mode.

[0029] The above controller can control the voltage converter to be deactivated when the storage capacity of the low-voltage battery is greater than or equal to a third set value after activating the voltage converter in the charging mode.

[0030] The above controller can be controlled to switch to a sleep state in which control means related to the control of high-voltage electric loads operated by high-voltage power in the charging mode are deactivated.

[0031] A battery management system for an agricultural electric vehicle according to a second aspect of the present invention comprises: a high-voltage battery that provides high-voltage power and is configured to be charged with external power; a low-voltage battery that provides low-voltage power lower than that of the high-voltage battery and is configured to be charged with the power of the high-voltage battery; a voltage converter that converts the power of the high-voltage battery into low voltage and supplies the low-voltage power to the low-voltage battery and low-voltage electrical loads; and a controller that controls the voltage converter to be activated or deactivated in order to increase the charging speed of the high-voltage battery in a charging mode for the high-voltage battery.

[0032] A battery management method for an agricultural electric vehicle according to a first aspect of the present invention comprises: a first confirmation step of confirming whether the voltage of a low-voltage battery is higher than a first set value; a deactivation step of deactivating the voltage converter if the voltage of the low-voltage battery is confirmed to be higher than the first set value in the first confirmation step; and an activation step of activating the voltage converter if the voltage of the low-voltage battery is confirmed to be lower than the first set value in the first confirmation step; wherein the first confirmation step, the deactivation step, and the activation step are performed in a charging mode in which a high-voltage battery is charged.

[0033] After the deactivation step, a second confirmation step of confirming whether the voltage of the low-voltage battery is less than a second set value is further included; and if the voltage of the low-voltage battery is confirmed to be less than the second set value in the second confirmation step, the activation step is entered, and the second set value is a voltage value lower than the first set value.

[0034] After the above activation step, a third confirmation step is further included to confirm whether the storage capacity of the low-voltage battery is equal to or greater than a third set value; and if the storage capacity of the low-voltage battery is equal to or greater than the third set value in the third confirmation step, the system enters the deactivation step.

[0035] The present invention may further include a sleep stage in which, when charging of the high-voltage battery begins, control means related to the control of high-voltage electrical loads operated by high-voltage power are deactivated and switched to a sleep state.

[0036] The above dormant step may be performed before the first verification step.

[0037] According to the present invention, there is an effect of improving the charging speed of a high-voltage battery while maintaining the stability of a low-voltage battery.

[0038] FIG. 1 is a configuration diagram of a battery management system for an agricultural electric vehicle according to one embodiment of the present invention.

[0039] Figure 2 is a reference diagram for explaining a power distributor applied to the management system of Figure 1.

[0040] Figure 3 is a reference diagram for explaining the operating status of the management system of Figure 1.

[0041] Figure 4 is a flowchart for explaining a battery management method performed in the management system of Figure 1.

[0042] A preferred embodiment according to the present invention is described with reference to the attached drawings, but for the sake of brevity, descriptions of well-known components are omitted or compressed as much as possible.

[0043] FIG. 1 is a configuration diagram of a battery management system (100, hereinafter abbreviated as “management system”) for an agricultural electric vehicle according to one embodiment of the present invention.

[0044] The management system of Fig. 1 includes a high-voltage battery (110), a low-voltage battery (120), a voltage converter (130), a power relay (140), and a controller (150).

[0045] A high-voltage battery (110) is provided to provide high-voltage (DC 360 V) power used for driving agricultural electric vehicles or for driving agricultural work.

[0046] The low-voltage battery (120) is designed to provide power at a lower voltage (DC 12 V) than the high-voltage battery (110). For example, the operation of various lights, starting / stopping, and various control operations of an agricultural electric vehicle are performed using the power of the low-voltage battery (120).

[0047] According to the present invention, a lithium-ion battery is considered to be applied as a low-voltage battery (120). However, the present invention does not exclude the application of a lead-acid battery as a low-voltage battery (120).

[0048] A voltage converter (130) is provided to convert high voltage power of a high voltage battery (110) into low voltage power.

[0049] A voltage converter (130) is placed between a high-voltage battery (110) and a low-voltage battery (120). More specifically, the voltage converter (130) is placed between a power relay (140) and the low-voltage battery (120).

[0050] Additionally, a voltage converter (130) is placed between a high-voltage battery (110) and a low-voltage electrical load. More specifically, the voltage converter (130) is placed between a power relay (140) and a low-voltage electrical load.

[0051] Therefore, the low-voltage power output from the voltage converter (130) is provided to the low-voltage battery (120) or low-voltage electric loads.

[0052] According to the present invention, the voltage converter (130) can be activated or deactivated by the control of the controller (150). Therefore, the power required to activate and deactivate the voltage converter (130) is low voltage.

[0053] The power relay (140) relays the power provided from the high-voltage battery (110) to the voltage converter (130).

[0054] The power relay (140) may be a power distributor or may include a power distributor. Thus, the power relay (140) can distribute the power of the high-voltage battery (110) to high-voltage electrical loads.

[0055] Referring to Fig. 2, the power relay (140) distributes power to an electric motor (M), a hydraulic motor (P), a heater (H), a fan motor (F), a compressor (C), and a voltage converter (130).

[0056] However, if the power is implemented to be directly transmitted from the high-voltage battery (110) to the voltage converter (130), the power relay (140) may be omitted.

[0057] The controller (150) may be the highest-level control means among the many control means applied to agricultural electric vehicles. Therefore, the controller (150) may comprehensively manage all other control means applied to agricultural electric vehicles. Accordingly, the controller (150) may be referred to as an EVCU (Electric Vehicle Controller Unit). Furthermore, the controller (150) may ultimately control the operation of all controllable electrical loads by controlling the lower-level control means.

[0058] However, the controller (150) may not be a top-level control means, but may be a separate control means capable of commanding the charging process.

[0059] According to the present invention, the controller (150) can control to activate or deactivate the voltage converter (130).

[0060] According to a preferred example of the present invention, the controller (150) can control to activate or deactivate the voltage converter (130) by checking the voltage of the low voltage battery (120). For example, the controller (150) controls to activate the voltage converter (130) when the voltage of the low voltage battery (120) is higher than a first set value (e.g., '11 V'), and controls to deactivate the voltage converter (130) when the voltage of the low voltage battery (120) is lower than a second set value (e.g., '10.5 V').

[0061] If the voltage converter (130) is deactivated, the controller (150) controls the low-voltage electrical components to operate with power from the low-voltage battery (120).

[0062] According to a preferred example of the present invention, the controller (150) can check the storage capacity of the low-voltage battery (120). Here, the storage capacity can also be calculated as a percentage. Therefore, when the total storage capacity is 100%, the storage capacity checked by the controller (150) can theoretically have a value between 0 and 100%.

[0063] The controller (150) can control the voltage converter (130) to be deactivated according to the storage amount of the confirmed low-voltage battery (120). For example, if the storage amount of the low-voltage battery (120) is greater than or equal to a third set value (e.g., '90%'), the controller (150) controls the voltage converter (130) to be deactivated.

[0064] Of course, depending on the implementation, the controller (150) may be implemented to activate the voltage converter (130) according to the storage capacity of the low-voltage battery (120) for other operating examples of the management system (100).

[0065] The controller (150) can also control control means related to the control of high-voltage electrical loads to be switched to a dormant state. Here, the high-voltage electrical loads may be electric motors (M) or hydraulic motors (P), etc.

[0066] The power generated by the electric motor (M) is primarily used for driving agricultural electric vehicles and for agricultural work. The power generated by the hydraulic motor (P) can be primarily used for steering, agricultural work, or braking.

[0067] For reference, let's briefly look at the high-voltage and low-voltage loads mentioned in the descriptions above.

[0068] The term "electric loads" refers to electrical components that discharge a high-voltage battery (110) or a low-voltage battery (120) by consuming power.

[0069] In agricultural electric vehicles, electrical loads can be divided into high-voltage electrical loads and low-voltage electrical loads.

[0070] High-voltage electrical loads consume high-voltage power from the high-voltage battery (110). On the other hand, low-voltage electrical loads consume low-voltage power from the low-voltage battery (120).

[0071] High voltage electrical loads may include electric motors (M), hydraulic motors (P), and compressors (C).

[0072] Low-voltage electrical loads may include ignition on / off keys, various lights, an On Board Charge (OBC), and various control devices. Here, the OBC is a voltage conversion device. The OBC converts AC power from the electric vehicle supply equipment (EVSE) into DC power and supplies it to the high-voltage battery (110).

[0073] Meanwhile, various control means include a controller (150).

[0074] In addition, various control means may include a battery management system (BMS), an electric vehicle communication controller (EVCC), a transmission control unit (TCU), a hydraulic control means, etc. located at a lower level of the controller (150).

[0075] The battery management system (BMS) monitors battery voltage, temperature, current, and performs battery error diagnosis and protection functions. Specifically, the BMS monitors the charging process and manages it using an optimal charging algorithm to ensure safe and efficient charging.

[0076] The electric vehicle communication controller verifies whether the battery management system and OBC are ready for charging and communicates these confirmations to the electric vehicle charging device.

[0077] The TCU controls the electronically operated transmission.

[0078] The hydraulic control means controls the hydraulic pressure.

[0079] According to the management system (100) having the above configuration, the voltage converter (130) can be activated or deactivated.

[0080] Figure 1 illustrates a state in which the voltage converter (130) is currently activated. In the state of Figure 1, low-voltage power output from the voltage converter (130) is provided to the low-voltage battery (120) and low-voltage electrical loads. Therefore, the low-voltage electrical loads operate with the low-voltage power output from the voltage converter (130), and the low-voltage battery (120) is also charged. In addition, the power of the low-voltage battery (120) is not provided to the low-voltage electrical loads. Since charging is performed while the discharge of the low-voltage battery (120) is stopped in this manner, the stability of the low-voltage battery (120) can be improved.

[0081] On the other hand, when the controller (150) deactivates the voltage converter (130), it switches to the state of FIG. 3.

[0082] In the state of Fig. 3, no power is output from the voltage converter (130). Therefore, the controller (150) controls the low-voltage electric load to operate with the power of the low-voltage battery (120).

[0083] Of course, the state of Fig. 1 and the state of Fig. 3 can be appropriately switched according to the control of the controller (150). In this way, the controller (150) can efficiently manage the high-voltage battery (110) and the low-voltage battery (120) by selectively activating or deactivating the voltage converter (130).

[0084] The management system (100) according to the present invention as described above can also operate to increase the charging speed of the high-voltage battery (110), especially in the charging mode for the high-voltage battery (110). That is, in the charging mode, the controller (150) activates or deactivates the voltage converter (130) while checking the status of the low-voltage battery (120). In the state of FIG. 3 where the voltage converter (130) is deactivated, the power of the high-voltage battery (110) is not utilized for charging the low-voltage battery (120) or operating low-voltage electrical loads. Therefore, the charging speed of the high-voltage battery (110) can be increased accordingly.

[0085] Below, a preferred example of a battery management method performed in an agricultural electric vehicle equipped with the management system (100) of FIG. 1 is described with reference to the flow chart of FIG. 4.

[0086] Figure 4 illustrates a battery management method performed in charging mode. For convenience, the steps are numbered and explained.

[0087] 1. Some control measures are dormant. <s11>

[0088] When charging of the high-voltage battery (110) begins, the controller (150) deactivates the control means related to controlling high-voltage electric loads operated by high-voltage power, thereby switching to a dormant state.

[0089] This is to prevent unnecessary power loss in charging mode.

[0090] For example, in charging mode, an agricultural electric vehicle cannot be driven or used for agricultural work. Therefore, the functions of TCU or hydraulic control means are not required. Accordingly, the controller (150) controls the TCU or hydraulic control means to enter a dormant state.

[0091] Typically, in charging mode, charging is accomplished through the operation of the controller (150), electric vehicle communication controller, battery management system, and OBC. Therefore, when various control means not directly related to charging are switched to a dormant state, power is not wasted, thereby increasing the charging speed of the high-voltage battery (110).

[0092] Step S11 may be implemented to be performed at any point during the process of steps S12 to S15 described below. However, it is most preferable to implement step S11 to be performed first after switching to charging mode and charging begins.

[0093] 2. First confirmation <s12>

[0094] The controller (150) checks whether the voltage of the low-voltage battery (120) is higher than a first set value. Here, the first set value is a voltage value preset in the controller (150).

[0095] It is preferable that the first setting value be a voltage value that allows the operation of low-voltage electric loads operating in charging mode with the power of the low-voltage battery (120) to be performed appropriately.

[0096] In one example, the first set value in a low voltage battery (120) for 12 V may be 11 V.

[0097] 3. Disable the voltage converter <s13>

[0098] In step S12, if the voltage of the low-voltage battery (120) is higher than the first set value, the controller (150) deactivates the voltage converter (130). Accordingly, the controller (150) controls the low-voltage electrical loads to operate using the power of the low-voltage battery (120). That is, after step S13, the controller (150), the electric vehicle communication controller, the battery management system, and the OBC operate using the power of the low-voltage battery (120).

[0099] When step S13 is performed, naturally, there is no power leaking from the high-voltage battery (110) through the voltage converter (130). Therefore, the charging speed of the high-voltage battery (110) increases.

[0100] 4. Second confirmation <s14>

[0101] With the voltage converter (130) disabled by step S13, the controller (150) continuously checks whether the voltage of the low-voltage battery (120) is less than the second set value.

[0102] The second setting value is also a voltage value preset in the controller (150).

[0103] The second set value is preferably a voltage value that can initiate charging when the low-voltage battery (120) has been discharged to a level that does not cause damage. Naturally, the second set value is a lower voltage than the first set value.

[0104] In one example, the second setpoint in a low voltage battery (120) for 12 V may be 10.5 V.

[0105] 5. Activate the voltage converter <s15>

[0106] If the voltage of the low voltage battery (120) is lower than the first set value in step S12, the controller (150) activates the voltage converter (130).

[0107] Also, if the voltage of the low voltage battery (120) is lower than the second set value in step S14, the controller (150) activates the voltage converter (130).

[0108] Accordingly, the management system (100) is brought into the state of Fig. 1. Therefore, the voltage converter (130) operates and the low-voltage battery (120) is charged. In addition, the low-voltage electrical loads, such as the controller (150), the electric vehicle communication controller, the battery management system, and the OBC, operate with the power output from the voltage converter (130).

[0109] The meaning of activation in this step S15 also includes the meaning of maintaining the state of the voltage converter (130) that was previously activated.

[0110] For example, activation of the voltage converter (130) immediately after step S12 may mean maintaining the activated state of the voltage converter (130) that is already activated.

[0111] For example, the activation of the voltage converter (130) that is performed sequentially after going through steps S13 and S14 in step S12 means activating the voltage converter (130) that is deactivated.

[0112] 6. Third confirmation <s16>

[0113] The controller (150) checks whether the storage capacity of the low-voltage battery (120) is equal to or greater than a third set value after the voltage converter (130) is activated by step S15. Here, the third set value is a value preset in the controller (150).

[0114] As an example, the third setting value may be a percentage of the total storage capacity of the low voltage battery (120).

[0115] For example, the third setting value may be a ratio of 90% of the total storage capacity of the low-voltage battery (120).

[0116] If the storage capacity is greater than the third set value, the controller (150) determines that the low-voltage battery (120) is sufficiently stable. Accordingly, the controller (150) deactivates the voltage converter (130) by controlling the process to proceed to step S13. Accordingly, the management system (100) transitions to the state of FIG. 3, and the charging speed of the high-voltage battery (110) increases.

[0117] The flow of steps S13 to S16 as above can be performed as needed throughout the charging time.

[0118] Additional Information

[0119] 1. Regarding voltage check

[0120] According to the present invention, the activation and deactivation of the voltage converter (130) is determined by checking the voltage, not the storage capacity, of the low-voltage battery (120). This can be particularly well combined with the special situation of charging.

[0121] For example, charging can be started and stopped arbitrarily by the administrator. Therefore, in charging mode, it may be more desirable to determine whether to activate or deactivate the voltage converter (130) based on the voltage of the low-voltage battery (120) rather than determining whether to activate or deactivate the voltage converter (130) based on the storage capacity of the low-voltage battery (120).

[0122] However, when entering step S13 from step S16, it may be more desirable to set the storage amount as a condition. This is because, if the voltage value is set as a condition in the process of entering step S13 from step S16, excessive control may be required to stabilize the low-voltage battery (120). In addition, a lot of power is consumed accordingly, which may actually lower the charging speed of the high-voltage battery (110).

[0123] In other words, since step S16 is for stabilizing the low-voltage battery (120), it is necessary to charge the low-voltage battery (120) until it is sufficiently stable. Therefore, it may be desirable that the condition for entering step S13 from step S16 is the storage capacity of the low-voltage battery (120).

[0124] In addition, since the voltage of the low-voltage battery (120) is monitored in the charging mode, the stability of the low-voltage battery (120) can be maintained while utilizing the power of the low-voltage battery (120) during the charging process.

[0125] 2. Regarding the inactivity of the voltage converter

[0126] When the voltage converter (130) is deactivated, power consumed by the operation of the voltage converter (130) can be saved, and power wasted due to the power conversion efficiency of the voltage converter (130) (typically less than 90%) can also be saved. Accordingly, the charging speed of the high-voltage battery (120) can be increased by that amount.

[0127] The above-described embodiments merely illustrate preferred examples of the present invention, and it may have various applications. Therefore, the present invention should not be construed as limited to the above-described content. Instead, the scope of the present invention should be construed within the scope of the separately described claims and their equivalents.

Claims

1. A high-voltage battery (110) that provides high-voltage power and can be charged with external power; A low-voltage battery (120) that provides low-voltage power lower than that of the high-voltage battery (110) and can be charged with the power of the high-voltage battery (110); A voltage converter (130) that converts the power of the high-voltage battery (110) into low voltage and supplies it to the low-voltage battery (120) and low-voltage electrical loads; and A controller (150) capable of checking the voltage of the low-voltage battery (120) and controlling the voltage converter (130) to activate or deactivate it; Battery management system for agricultural electric vehicles (100).

2. In paragraph 1, The above controller (150) is a battery management system (100) for an agricultural electric vehicle capable of controlling the voltage converter (130) to be deactivated when the voltage of the low-voltage battery (120) is higher than the first set value in the charging mode in which the high-voltage battery (110) is charged.

3. In paragraph 2, The above controller (150) can control the low-voltage electric loads to operate by the power of the low-voltage battery (120) when the voltage converter (130) is deactivated in the charging mode. Battery management system for agricultural electric vehicles (100).

4. In paragraph 2, The above controller (150) can control the low voltage battery (120) to be charged by activating the voltage converter (130) when the voltage of the low voltage battery (120) is lower than the second set value, which is lower than the first set value, after deactivating the voltage converter (130) in the charging mode. Battery management system for agricultural electric vehicles (100) 5. In paragraph 4, The above controller (150) can control the voltage converter (130) to be deactivated when the storage amount of the low voltage battery (120) is greater than the third set value after activating the voltage converter (130) in the charging mode. Battery management system for agricultural electric vehicles (100).

6. In paragraph 1, The above controller (150) can control the control means related to the control of high-voltage electric loads operated by high-voltage power in the charging mode to be switched to a dormant state in which they are deactivated. Battery management system for agricultural electric vehicles (100).

7. A high-voltage battery (110) that provides high-voltage power and can be charged with external power; A low-voltage battery (120) that provides low-voltage power lower than that of the high-voltage battery (110) and can be charged with the power of the high-voltage battery (110); A voltage converter (130) that converts the power of the high-voltage battery (110) into low voltage and supplies it to the low-voltage battery (120) and low-voltage electrical loads; and A controller (150) that controls to activate or deactivate the voltage converter (130) to increase the charging speed of the high-voltage battery (110) in the charging mode for the high-voltage battery (110); Battery management system for agricultural electric vehicles (100).

8. First verification step to check whether the voltage of the low voltage battery (120) is higher than the first set value <s12> ;< / s12> The first verification step above <s12>When the voltage of the low voltage battery (120) is confirmed to be higher than the first set value, a deactivation step is performed to deactivate the voltage converter (130). <s13> ; and< / s13> The first verification step above <s12>When the voltage of the low voltage battery (120) is confirmed to be less than the first set value, an activation step for activating the voltage converter (130) <s15> ; including,< / s15> The first verification step above <s12>, the above deactivation step <s13>and the above activation step <s15> It is carried out in charging mode where a high-voltage battery (110) is charged.< / s15> Battery management method for agricultural electric vehicles.

9. In paragraph 8, The above deactivation step <s13>Afterwards, a second confirmation step is performed to check whether the voltage of the low-voltage battery (120) is less than the second set value. <s14> ; including more,< / s14> The second verification step above <s14>If the voltage of the low voltage battery (120) is confirmed to be less than the second set value, the activation step <s15> Entering into,< / s15> The above second setting value is a lower voltage value than the above first setting value. Battery management method for agricultural electric vehicles.

10. In paragraph 8, The above activation step <s15>Afterwards, a third confirmation step is performed to check whether the storage capacity of the low-voltage battery (120) is greater than or equal to the third set value. <s16> ; including more,< / s16> The third verification step above <s16>If the storage capacity of the low voltage battery (120) is greater than the third set value, the inactive stage <s13> Entering into< / s13> Battery management method for agricultural electric vehicles.

11. In paragraph 8, When the charging of the above high-voltage battery (110) starts, the control means related to the control of high-voltage electric loads operated by high-voltage power are deactivated and switched to a dormant state. <s11> ; including more< / s11> Battery management method for agricultural electric vehicles.

12. In paragraph 11, The above dormant stage <s11>is the first verification step above <s12> performed before< / s12> Battery management method for agricultural electric vehicles.

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