Electric construction machine battery protection method, thermal management system, and electric construction machine

Abstract

Disclosed are an electric construction machine battery protection method, a thermal management system, and an electric construction machine, for use in protecting a battery when the electric construction machine performs energy recovery. On the basis of the relationship between an allowable recharging power of the battery and a required braking power of the electric construction machine, when the required braking power is low, part of recovered electric energy is inputted into the battery at the allowable recharging power, and the other part of the recovered electric energy is inputted into an energy consumption component for consumption, so that electric energy obtained from energy recovery is prevented from being inputted into the battery without limitation, thereby protecting the battery during energy recovery.

Description

Battery protection methods, thermal management systems, and electric construction machinery for electric construction machinery

[0001] This application claims priority to Chinese Patent Application No. 202410692417.2, filed on May 30, 2024, entitled "Battery Protection Method, Thermal Management System and Electric Engineering Machinery", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of engineering machinery technology, specifically to a battery protection method for electric engineering machinery, a thermal management system, and electric engineering machinery. Background Technology

[0003] Electric construction machinery can achieve braking through energy recovery mechanisms during operation. Energy recovery refers to the process of converting the kinetic energy of an electric vehicle into electrical energy for storage or utilization when the vehicle decelerates.

[0004] The electrical energy recovered by the energy recovery system can flow to the battery of electric engineering machinery. However, given the limited capacity of the battery to receive electrical energy, unlimited input of recovered electrical energy into the battery may damage it.

[0005] Therefore, how to protect the battery when electric construction machinery performs energy recovery is an urgent problem to be solved. Summary of the Invention

[0006] In view of this, this application aims to provide a battery protection method, thermal management system and electric construction machinery for electric construction machinery, so as to protect the battery when the electric construction machinery is performing energy recovery.

[0007] In a first aspect, embodiments of this application provide a method for protecting the battery of electric engineering machinery, including:

[0008] Based on the battery state parameters of the electric construction machinery battery, the allowable recharge power of the electric construction machinery battery is determined, and the battery state parameters include battery capacity and cell temperature.

[0009] The required braking power of the electric construction machinery is obtained. When the required braking power is greater than the allowable recharge power, a portion of the electrical energy obtained through energy recovery is input into the battery of the electric construction machinery at the allowable recharge power, and the remaining portion of the electrical energy obtained through energy recovery is input into the energy consumption component of the electric construction machinery.

[0010] Optionally, it also includes:

[0011] When the required braking power is less than or equal to the allowable recharge power, all the electrical energy obtained from energy recovery will be input into the electric engineering machinery battery.

[0012] or,

[0013] When the required braking power is less than or equal to the allowable recharge power, a portion of the recovered electrical energy is input into the energy consumption component of the electric construction machinery, and the remaining portion of the recovered electrical energy is input into the battery of the electric construction machinery.

[0014] Optionally, obtaining the required braking power of the electric construction machinery includes:

[0015] The required braking power of the electric construction machinery is obtained based on its kinetic energy, gravitational potential energy component, required braking time, rolling resistance, and required braking distance.

[0016] The method further includes:

[0017] The sum of the maximum power of the energy-consuming component and the allowable recharge power is calculated as the maximum braking power for energy recovery;

[0018] When the required braking power is greater than the maximum energy recovery braking power, the braking system of the electric engineering machinery is controlled to output braking torque to meet the braking requirements.

[0019] Optionally, it also includes:

[0020] When the battery cell temperature is within the preset limit temperature range, the electric engineering machinery is controlled to park.

[0021] or,

[0022] When the cell temperature is within the preset speed-limiting temperature range and the electric construction machinery battery is not heated or cooled, the electric construction machinery is controlled to park.

[0023] or,

[0024] When the cell temperature is within the speed-limiting temperature range and the battery of the electric construction machinery is being heated or cooled, the output power of the electric construction machinery is limited.

[0025] Optionally, the method is also used to send control commands to control the operation of the battery thermal management system of electric construction machinery;

[0026] The electric construction machinery battery thermal management system is used to heat or cool the electric construction machinery battery.

[0027] The electric engineering machinery battery thermal management system includes: a PTC heater;

[0028] The PTC heater is used as the energy-consuming component to receive electrical energy obtained from energy recovery and convert the electrical energy into heat energy.

[0029] Optionally, the method further includes:

[0030] Send control commands to control the electric construction machinery battery thermal management system to determine the working mode of the electric construction machinery battery thermal management system based on the cell temperature. The working mode of the electric construction machinery battery thermal management system includes a heating mode and a cooling mode.

[0031] The heating modes include a driving heating mode and a charging heating mode, and the cooling modes include a driving cooling mode and a charging cooling mode.

[0032] The electric construction machinery battery thermal management system determines its operating mode based on the cell temperature, including:

[0033] The electric construction machinery battery thermal management system determines its operating mode based on the cell temperature and the operating status of the electric construction machinery.

[0034] Optionally, the electric construction machinery battery thermal management system further includes a water-cooled unit;

[0035] The method further includes:

[0036] Send control commands to control the electric engineering machinery battery thermal management system to determine the working mode of the water-cooled unit and the PTC heater according to the working mode and the inlet temperature of the water-cooled unit. The working modes of the water-cooled unit include cooling mode, self-circulation mode, heating mode and shutdown mode.

[0037] The electric engineering machinery battery thermal management system determines the operating mode of the water-cooled unit and the PTC heater based on the operating mode and the inlet temperature of the water-cooled unit, including:

[0038] The electric engineering machinery battery thermal management system determines the operating mode of the water-cooled unit and the PTC heater in the next operating stage based on the operating mode, the inlet temperature of the water-cooled unit, and the operating mode of the water-cooled unit and the PTC heater in the previous operating stage.

[0039] Secondly, embodiments of this application provide a thermal management system for an electric engineering machinery battery, including a vehicle controller and a PTC heater;

[0040] The vehicle controller is used to determine the allowable recharge power of the electric construction machinery battery based on the battery state parameters, including battery charge and cell temperature; obtain the required braking power of the electric construction machinery; when the required braking power is greater than the allowable recharge power, input a portion of the energy recovered through energy recovery into the electric construction machinery battery at the allowable recharge power, and input the remaining portion of the energy recovered through energy recovery into the energy consumption components of the electric construction machinery.

[0041] The PTC heater is used as the energy-consuming component to receive electrical energy obtained from energy recovery and convert the electrical energy into heat energy.

[0042] Optionally, the electric construction machinery battery thermal management system further includes: a thermal management controller and a water-cooled unit;

[0043] The thermal management controller is used to determine the working mode of the electric construction machinery battery thermal management system according to the cell temperature. The working mode of the electric construction machinery battery thermal management system includes a heating mode and a cooling mode.

[0044] The thermal management controller is also used to control the electric engineering machinery battery thermal management system to determine the working mode of the water-cooled unit and the PTC heater according to the working mode and the inlet temperature of the water-cooled unit. The working modes of the water-cooled unit and the PTC heater include cooling mode, self-circulation mode, heating mode and shutdown mode.

[0045] Thirdly, embodiments of this application provide an electric construction machinery, including an electric construction machinery battery thermal management system as described in the second aspect.

[0046] This application provides a battery protection method for electric construction machinery. Based on the relationship between the battery's permissible recharge power and the electric construction machinery's required braking power, when the required braking power is low, a portion of the recovered electrical energy is input into the battery to meet the permissible recharge power, while the other portion is input into energy-consuming components for consumption. This avoids the unlimited input of recovered electrical energy into the battery, thus achieving battery protection during energy recovery. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0048] Figure 1 is a flowchart illustrating a battery protection method for electric engineering machinery provided in an embodiment of this application.

[0049] Figure 2 is an implementation logic diagram of an example of a battery protection method for electric engineering machinery provided in an embodiment of this application.

[0050] Figure 3 is a schematic diagram of the structure of a battery thermal management system for electric engineering machinery provided in an embodiment of this application. Detailed Implementation

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] The first embodiment of this application provides a battery protection method for electric engineering machinery, as shown in FIG1. ​​The method may include the following steps:

[0053] Step 101: Determine the allowable recharge power of the electric construction machinery battery based on the battery status parameters, which include battery capacity and cell temperature.

[0054] When energy is recovered through an energy recovery mechanism, the movement of the electric machinery drives the electric motor of the electric engineering machinery, generating electrical energy through electromagnetic induction, thus converting mechanical energy into electrical energy. One way to use the recovered electrical energy is to store it in batteries.

[0055] Because the physical characteristics of a battery dictate that electrical energy cannot be input into the battery without any restriction, this embodiment proposes determining the allowable recharge power of the battery based on battery state parameters. Battery state parameters reflect the current state of the battery, such as its current charge level and the temperature of the battery cells.

[0056] For example, Table 1 provides an example of determining the permissible charging current based on battery charge and cell temperature. The unit of current in Table 1 is amperes (A). It is stipulated that the current is positive when the battery is discharging and negative when it is charging. Taking a battery with 50% charge and a cell temperature of 10°C as an example, Table 1 shows that the maximum permissible input current for this charge and temperature is 181.8A. At 50% charge and a cell temperature of 10°C, a recharge current exceeding 181.8A will damage the battery.

[0057] Table 1. Comparison of Battery Capacity, Cell Temperature, and Permissible Recharge Current

[0058] After obtaining the allowable charging current, the allowable recharge power of the battery, also known as the maximum allowable recharge power, can be calculated based on the allowable charging current.

[0059] When calculating the maximum permissible recharge power of a battery, it is necessary to select an appropriate method for calculating the permissible recharge power based on the battery type. For example, one battery recharge method is pulse charging, which is performed in 30-second cycles. After each pulse charge, the battery enters a charging sleep period, which is generally slightly longer than the pulse charge time. During the charging sleep period, the battery can be in a discharging state or a zero-output state, but the battery is not allowed to undergo pulse charging again during the charging sleep period. For batteries that receive and recover energy using the above-mentioned pulse charging, the battery is charged with the maximum battery recharge current during the pulse charge time. However, when calculating the maximum permissible recharge power, it is necessary to calculate the average power including the pulse charge time and the charging sleep time as the maximum permissible recharge power.

[0060] Step 102: Obtain the required braking power of the electric construction machinery. When the required braking power is greater than the allowable recharge power, input a portion of the electrical energy obtained from energy recovery into the battery of the electric construction machinery at the allowable recharge power, and input the remaining portion of the electrical energy obtained from energy recovery into the energy consumption components of the electric construction machinery.

[0061] To protect the battery during energy recovery, the battery can only be charged at its maximum allowable recharge power. By comparing the required braking power and the allowable recharge power, it can be determined whether all the electrical energy generated by the energy recovery mechanism can be input into the battery. When the required braking power exceeds the battery's allowable recharge power, the battery cannot accept all the electrical energy generated by energy recovery, and the excess recovered electrical energy needs to be consumed through other channels. Since there are many energy-consuming components in electric construction machinery that use electrical energy, such as DC-DC systems (DC-DC systems: power steering systems, air conditioning, and other electronic devices), the remaining electrical energy can be input into these energy-consuming components to consume the excess recovered electrical energy.

[0062] Demand braking power is a quantitative description of the braking capacity required by engineering machinery. One way to obtain demand braking power is to preset a set of data corresponding to the demand braking power and the braking demand. For example, taking the pressing of the brake pedal as the braking demand, a data correspondence is established between the depth of the driver pressing the brake pedal and the demand braking power. When the brake pedal is detected to be pressed to a certain depth, the data corresponding to the depth of pressing is taken as the demand braking power for that braking action.

[0063] The second embodiment of this application further specifies the electric construction machinery battery protection method in more detail and with greater specificity than the first embodiment. Some or all of the technical features in the second embodiment can be combined with or replaced by the first embodiment, either individually or in combination, to obtain more feasible electric construction machinery battery protection methods.

[0064] The battery protection method for electric engineering machinery in the second embodiment of this application is described in detail below:

[0065] Optionally, the battery protection method for electric construction machinery further includes: when the required braking power is less than or equal to the allowable recharge power, inputting all the electrical energy recovered into the electric construction machinery battery; or, when the required braking power is less than or equal to the allowable recharge power, inputting a portion of the electrical energy recovered into the energy-consuming components of the electric construction machinery, and inputting the remaining portion of the electrical energy recovered into the electric construction machinery battery.

[0066] This embodiment proposes that, based on the relationship between the required braking power and the allowed recharge power, several other methods for determining the flow of electrical energy obtained through energy recovery can also be used.

[0067] For example, if the battery can accept all the electrical energy generated by energy recovery, then all the electrical energy can be recharged back to the battery; or, even if the battery can accept all the electrical energy generated by energy recovery, the electrical energy generated by energy recovery can still be divided into two parts: one part of the electrical energy generated by energy recovery is input into energy-consuming components, such as DC-DC systems, and the other part is input into the battery. Since energy-consuming components such as DC-DC systems require electrical energy to operate, directly inputting the electrical energy generated by energy recovery into the energy-consuming components can avoid the energy waste of first inputting electrical energy into the battery and then drawing power from the battery to power the energy-consuming components.

[0068] Optionally, obtaining the required braking power of the electric construction machinery includes: calculating the required braking power of the electric construction machinery based on its kinetic energy, gravitational potential energy component, required braking time, rolling resistance, and required braking distance; the battery protection method for the electric construction machinery further includes: calculating the sum of the maximum power of the energy-consuming components and the allowable recharge power as the maximum energy recovery braking power; when the required braking power is greater than the maximum energy recovery braking power, controlling the braking system of the electric construction machinery to output braking torque to meet the braking demand.

[0069] This embodiment proposes another method for obtaining the required braking power of electric construction machinery. The required braking power is calculated using parameters such as the kinetic energy of the electric construction machinery, the component of gravitational potential energy in the braking direction, the required braking time, rolling resistance, and the required braking distance. Specifically, the required braking power can be calculated using the following formula:

[0070] Required braking power = (kinetic energy of electric construction machinery + gravitational potential energy component) / required braking time - ((rolling resistance) × required braking distance) / required braking time - other power of electric construction machinery.

[0071] Other power of electric construction machinery includes the power of the oil pump motor and the power of the DC-DC converter. It is particularly important to note that, because this data is specifically used for comparison with the battery's allowable recharge power in this method, the "demanded braking power" in this embodiment differs from the conventional understanding of demanded braking power. It means "the braking power required by the battery during this braking action," therefore, the parameter "other power of electric construction machinery" needs to be subtracted during calculation. If conventionally understood as the demanded braking power for the entire vehicle, the parameter "other power of electric construction machinery" should not be included in the calculation.

[0072] The sum of the maximum power of the energy-consuming component and the allowable recharge power is taken as the maximum braking power for energy recovery. When the required braking power exceeds the maximum braking power for energy recovery, it indicates that relying solely on energy recovery cannot fully meet the braking requirements, and the braking system of the electric engineering machinery needs to be controlled to assist in physical braking to meet the braking needs.

[0073] Optionally, the battery protection method for electric construction machinery further includes: controlling the electric construction machinery to park when the cell temperature is within a preset speed-limiting temperature range; or, controlling the electric construction machinery to park when the cell temperature is within a preset speed-limiting temperature range and the battery of the electric construction machinery is not being heated or cooled; or, limiting the output power of the electric construction machinery when the cell temperature is within the speed-limiting temperature range and the battery of the electric construction machinery is being heated or cooled.

[0074] As explained above, a battery's performance is affected by its state parameters, and the permissible recharge current that ensures battery safety varies at different cell temperatures. In fact, not only is the recharge current affected by cell temperature, but the battery's discharge capacity is also influenced by cell temperature. Therefore, when the battery's permissible recharge current decreases, the braking power that the battery can provide will also decrease, reducing the braking capability of the electric construction machinery and affecting its braking safety.

[0075] Therefore, this embodiment proposes to intervene and control the operation of the electric construction machinery when the cell temperature has a significant impact on the battery's performance. For example, when the cell temperature is -30°C, the battery's performance is greatly affected, and continued operation at this temperature may cause significant damage to the battery. In this case, the driver's control commands should be stopped, and the electric construction machinery should be forcibly controlled to gradually stop operating to ensure battery safety. The electric construction machinery can also be inspected to determine if there is a malfunction in its thermal management system.

[0076] This embodiment specifically defines the control logic for the operation of electric construction machinery. The battery cell temperature is divided into several temperature ranges, and corresponding control methods are adopted according to the temperature range in which the battery cell temperature falls.

[0077] This embodiment specifically defines two temperature ranges: a restricted operating temperature range and a speed-limited temperature range. When the cell temperature is within the restricted operating temperature range, it is considered that operation at this temperature may cause significant damage to the battery, requiring forced control to gradually bring the electric construction machinery to a stop. When the cell temperature is within the speed-limited temperature range, it is considered that the battery's braking capacity is low at this temperature. If the battery temperature is not adjusted at this time, continued operation at this temperature is considered to cause significant damage to the battery, requiring forced control to gradually bring the electric construction machinery to a stop. If battery temperature adjustment is already underway, the output power of the construction machinery needs to be limited to restrict its speed and ensure braking safety. When the cell temperature is within the normal temperature range outside the restricted operating temperature range and the speed-limited temperature range, it is considered that the battery's working capacity is strong at this temperature, and no intervention in the control of the construction machinery is required.

[0078] The endpoint values ​​of each temperature range can be set according to specific needs. For example, the following temperature range can be set, where Tmin is the lowest cell temperature, Tmax is the highest cell temperature, and Tmean is the average cell temperature:

[0079] Traffic restrictions apply to the following temperature ranges: low temperature (Tmin < -10℃, Tmean < -7℃), high temperature (Tmax > 55℃, Tmean > 51℃).

[0080] Speed-limited temperature ranges: Low temperature (-10℃ <= Tmin < 0℃, -7℃ <= Tmean < 3℃), High temperature (50℃) <Tmax<=55℃,46℃<=Tmean<51℃)。

[0081] Optionally, the method is also used to send control commands to control the operation of the electric construction machinery battery thermal management system; the electric construction machinery battery thermal management system is used to heat or cool the electric construction machinery battery; the electric construction machinery battery thermal management system includes: a PTC heater; the PTC heater is used as an energy-consuming component to receive the electrical energy obtained from energy recovery and convert the electrical energy into heat energy.

[0082] This embodiment proposes that the method can send control commands to control the operation of the electric construction machinery battery thermal management system. The electric construction machinery battery thermal management system includes a PTC heater, which, as an energy-consuming component, consumes electrical energy and converts the consumed electrical energy into heat energy.

[0083] The thermal management system for electric construction machinery batteries can be considered the battery's air conditioner, adjusting the battery temperature by managing heat. For example, when the battery cell temperature is low, the operation of a PTC heater can generate heat to warm the battery, ensuring that it operates at a more suitable temperature.

[0084] Optionally, the battery protection method for electric construction machinery further includes: sending control commands to control the electric construction machinery battery thermal management system to determine its operating mode based on the cell temperature. The operating modes of the electric construction machinery battery thermal management system include a heating mode and a cooling mode. The heating mode includes a driving heating mode and a charging heating mode, and the cooling mode includes a driving cooling mode and a charging cooling mode. The method of determining the operating mode of the electric construction machinery battery thermal management system based on the cell temperature includes: the electric construction machinery battery thermal management system determining its operating mode based on the cell temperature and the operating status of the electric construction machinery.

[0085] The electric construction machinery battery thermal management system can operate in different modes based on different cell temperatures according to preset control logic to achieve thermal management of the battery. The operating modes include heating and cooling; when the battery temperature is too low, the battery is heated, and when the battery temperature is too high, the battery is cooled.

[0086] As proposed in the first embodiment, the physical characteristics of the battery determine that electrical energy cannot be input into the battery without any restrictions. The current charge level of the battery and the temperature of the battery cells affect the magnitude of the recharge current that the battery can safely accept. For example, regarding cell temperature, excessively high or low cell temperatures will significantly reduce the recharge current that the battery can safely accept.

[0087] This embodiment proposes inputting excess electrical energy that the battery cannot accept into the PTC heater to adjust the cell temperature. For example, when the battery temperature is too low, the battery can only accept a small recharge current, resulting in a large amount of residual electrical energy that cannot be input. Inputting this residual electrical energy into the PTC heater generates heat to heat the battery, causing the cell temperature to gradually increase until it returns to normal. As the cell temperature increases to normal, the battery's acceptable recharge current gradually increases, and the amount of residual electrical energy that cannot be input decreases. Therefore, the electrical energy received by the PTC heater gradually decreases, reducing the heat generated for battery heating and effectively preventing overheating.

[0088] In summary, this embodiment proposes a thermal energy management method for electric engineering machinery. It cleverly combines the electrical energy management method in the first embodiment and realizes the control logic of "abnormal cell temperature → a large amount of excess electrical energy is input into the PTC heater → a large amount of heat is generated to regulate the cell temperature → the cell temperature is normal → excess electrical energy is reduced, the electrical energy input into the PTC heater is reduced, and no more large amount of heat is generated. At this time, the cell temperature is also normal, and no more large amount of heat is needed for heating." This makes the control logic of electrical energy and thermal energy in electric engineering machinery in a positive cycle, and their interaction promotes the change of battery cell temperature towards normal temperature.

[0089] Based on the different operating states of electric construction machinery, the working modes of the electric construction machinery battery thermal management system can be further subdivided. In this embodiment, the working modes are further subdivided into driving heating mode, charging heating mode, driving cooling mode, and charging cooling mode.

[0090] Clearly, some of the above operating modes are used when the electric construction machinery is running (driving), such as the driving heating and cooling modes; others are used when the electric construction machinery is parked and charging, such as the charging heating and cooling modes. Therefore, the operating mode of the electric construction machinery battery thermal management system needs to be determined not only based on the cell temperature but also in conjunction with the operating status of the electric construction machinery.

[0091] Optionally, the electric construction machinery battery thermal management system further includes a water-cooled unit; the electric construction machinery battery protection method further includes: sending control commands to control the electric construction machinery battery thermal management system to determine the operating mode of the water-cooled unit and the PTC heater according to the operating mode and the inlet temperature of the water-cooled unit, wherein the operating mode of the water-cooled unit includes a cooling mode, a self-circulation mode, a heating mode, and a shutdown mode; optionally, the electric construction machinery battery thermal management system determines the operating mode of the water-cooled unit and the PTC heater according to the operating mode and the inlet temperature of the water-cooled unit, including: the electric construction machinery battery thermal management system determines the operating mode of the water-cooled unit and the PTC heater in the next operating stage according to the operating mode, the inlet temperature of the water-cooled unit, and the operating mode of the water-cooled unit and the PTC heater in the previous operating stage.

[0092] In practice, the operation of the coolant in the electric construction machinery battery thermal management system varies depending on the inlet temperature and the operating mode of the system. Specifically, this includes three methods: heating the coolant via a PTC heater or water-cooled unit; cooling the coolant via a water-cooled unit; or not controlling the coolant temperature but simply ensuring continuous circulation throughout the system. For example, when the system is in heating mode, the construction machinery needs to heat up, but the coolant temperature also needs to be controlled within a certain range to ensure that the coolant provides heat to the battery without causing the battery to rapidly overheat into a dangerously high temperature range. Therefore, when the coolant temperature is sufficient, even if the electric construction machinery battery thermal management system is in heating mode, the water-cooled unit and PTC heater may not be in heating mode. The water-cooled unit may be in self-circulation mode circulating the coolant, while the PTC heater may be off and not heating.

[0093] Water-cooled chillers mainly have several operating modes, including cooling mode, self-circulation mode, heating mode, and shutdown mode. PTC heaters mainly have heating mode and shutdown mode. The heating mode of the PTC heater can be used in conjunction with the heating mode of the water-cooled chiller to consume electrical energy and heat the coolant. The shutdown mode of the PTC heater is when heating the coolant is not required, and the PTC heater is turned off.

[0094] Furthermore, this embodiment proposes that the operating modes of the water-cooled unit and PTC heater should not only be considered based on the inlet temperature of the water-cooled unit according to the operating mode of the electric construction machinery battery thermal management system, but also in conjunction with the previous operating modes of the water-cooled unit and PTC heater to determine the subsequent operating modes. Specifically, when the cooling water temperature is at a moderate temperature, there are two scenarios. Taking the electric construction machinery battery thermal management system operating mode as heating mode as an example, one scenario is that heating has just begun, and the coolant is being heated to a higher temperature to raise the battery temperature. In this case, the operating mode of the water-cooled unit and PTC heater in the previous operating stage was heating mode, and the heating mode should continue. The other scenario is that heating has been going on for a period of time, and the battery temperature has reached normal and no longer requires a large amount of heat. Only a small amount of heat from the coolant is needed to maintain the battery temperature at a moderate temperature. In this case, the operating mode of the water-cooled unit and PTC heater in the previous operating stage may be cooling (to cool the excessively high-temperature coolant to a moderate temperature), self-circulation, or off. In this case, the self-circulation function should be executed to maintain the coolant at a moderate temperature to continue providing a small amount of heat to the battery.

[0095] For a more detailed explanation, this embodiment provides Table 2, which specifically provides a set of examples for determining the operating mode of the system according to the operating mode and the inlet temperature, and further determining the operating mode of the water-cooled unit in the system.

[0096] Table 2 Comparison Table of Operating Mode, Inlet Temperature and Operating Mode of Water-Cooled Unit

[0097] As shown in Figure 2, the third embodiment of the present application provides an example of the operation logic of an electric construction machinery equipped with the above-mentioned electric construction machinery battery thermal management system and operating the electric construction machinery battery protection method described in the first and / or second embodiments.

[0098] When condition 201 is satisfied, Tmax≥55°C or Tmin≤-10°C, which means the battery cells are in a super-high temperature or super-low temperature state, and the operation of the construction machinery needs to be stopped. This embodiment proposes that the operation of the construction machinery can be stopped through the following steps: 1. Decelerate and apply hydraulic parking; 2. Prohibit driving and work (such as vibration work); 3. Display an over-temperature fault prompt.

[0099] When condition 201 is not satisfied and condition 202 is satisfied, -10°C < Tmin < 0°C. If condition 205 is not satisfied and heating is not turned on, it means the battery is still in a low-temperature state and cannot charge back current, and the operation of the construction machinery needs to be stopped. If condition 205 is satisfied and heating has been turned on, the power of the construction machinery needs to be limited. This embodiment proposes that the power of the construction machinery can be limited through the following steps: 1. Decelerate; 2. Limit the maximum driving speed; 3. Display an over-temperature speed limit prompt. Then, calculate the required braking power based on the vehicle speed, and calculate the allowable charge-back power of the battery based on the feedback and calculation of the battery management system BMS.

[0100] When condition 201 is not satisfied, condition 202 is not satisfied, and condition 203 is satisfied, 50°C < Tmax < 55°C. If condition 206 is not satisfied and cooling is not turned on, it means the battery is still in a super-high temperature state and cannot charge back current, and the operation of the construction machinery needs to be stopped. If condition 206 is satisfied, the power of the construction machinery is limited. Then, calculate the required braking power based on the vehicle speed, and calculate the allowable charge-back power of the battery based on the feedback and calculation of the BMS.

[0101] If conditions 201, 202, and 203 are not met, but condition 204 is met, then Tmax ≤ 50℃ or Tmin > 0℃. If condition 207 is not met, the battery's allowable recharge power ≤ PTC power. This indicates that the battery cannot recharge the entire braking regenerative current, and the power of the construction machinery needs to be limited. Then, the required braking power is calculated based on the vehicle speed, and the allowable battery recharge power is obtained from the BMS feedback. If condition 207 is met, the required braking power can be directly calculated based on the vehicle speed, and the allowable battery recharge power can be obtained from the BMS feedback.

[0102] Condition 208 is not met, meaning no braking signal was received. This indicates that braking is not required through energy recovery, the battery does not need to recharge current, and the PTC heater does not need to consume recovered energy to provide braking capability.

[0103] If conditions 208 and 209 are met, it indicates that a braking signal has been received, and the battery's allowable recharge power is less than the required braking power. This means the battery cannot receive all the recovered energy. The PTC heater is activated, and when the required braking power is less than the maximum energy recovery power, energy recovery is used for braking. Maximum energy recovery power = PTC power + other vehicle energy consumption power + battery allowable recharge power. If condition 208 is met but condition 209 is not, it indicates that a braking signal has been received, and the battery's allowable recharge power meets the braking power requirement. Braking can then be performed according to the required braking power.

[0104] The fourth embodiment of this application provides a thermal management system for an electric construction machinery battery, including a vehicle controller and a PTC heater. The vehicle controller is used to determine the allowable recharge power of the electric construction machinery battery based on the battery state parameters, including battery charge and cell temperature; to obtain the required braking power of the electric construction machinery; when the required braking power is greater than the allowable recharge power, to input a portion of the recovered electrical energy into the electric construction machinery battery at the allowable recharge power, and to input the remaining portion of the recovered electrical energy into the energy consumption components of the electric construction machinery; and the PTC heater is used as an energy consumption component to receive the recovered electrical energy and convert it into heat energy.

[0105] The Vehicle Control Unit (VCU) plays a crucial role in automobiles. Its functions include collecting driver input such as signals from the accelerator, gear, and brake pedals to determine the driver's intentions; monitoring various vehicle status information in real time and issuing precise vehicle driving control commands to the powertrain and battery systems based on this information; and providing fault diagnosis, protection, and data storage functions.

[0106] In this embodiment, the VCU, as part of the electric construction machinery battery thermal management system, is used to implement the electric construction machinery battery protection method as described in the first embodiment of this application. The PTC heater, as an energy-consuming component, receives the electrical energy obtained through energy recovery and converts the electrical energy into heat energy.

[0107] The electric construction machinery battery thermal management system in this embodiment is used to implement the electric construction machinery battery protection method as described in the first and second embodiments, specifically including:

[0108] Based on the battery state parameters of the electric construction machinery battery, the allowable recharge power of the electric construction machinery battery is determined, and the battery state parameters include battery capacity and cell temperature.

[0109] The required braking power of the electric construction machinery is obtained. When the required braking power is greater than the allowable recharge power, a portion of the electrical energy obtained through energy recovery is input into the battery of the electric construction machinery at the allowable recharge power, and the remaining portion of the electrical energy obtained through energy recovery is input into the energy consumption component of the electric construction machinery.

[0110] Optionally, it also includes:

[0111] When the required braking power is less than or equal to the allowable recharge power, all the electrical energy obtained from energy recovery will be input into the battery of the electric engineering machinery.

[0112] or,

[0113] When the required braking power is less than or equal to the allowable recharge power, a portion of the electrical energy recovered is input into the energy-consuming components of the electric engineering machinery, and the remaining portion of the electrical energy recovered is input into the battery of the electric engineering machinery.

[0114] Optionally, the required braking power of the electric construction machinery is obtained, including:

[0115] The required braking power of the electric construction machinery is obtained based on its kinetic energy, gravitational potential energy component, required braking time, rolling resistance, and required braking distance.

[0116] The method also includes:

[0117] The maximum power of the energy-consuming component is calculated as the sum of the allowable recharge power, which is the maximum braking power for energy recovery.

[0118] When the required braking power exceeds the maximum energy recovery braking power, the braking system of the electric construction machinery is controlled to output braking torque to meet the braking demand.

[0119] Optionally, it also includes:

[0120] When the battery cell temperature is within the preset operating temperature range, the electric construction machinery is controlled to park.

[0121] or,

[0122] When the cell temperature is within the preset speed limit temperature range and the electric construction machinery battery is not heated or cooled, control the electric construction machinery to park.

[0123] or,

[0124] When the cell temperature is within the speed-limiting temperature range and the battery of the electric construction machinery is being heated or cooled, the output power of the electric construction machinery is limited.

[0125] Optionally, the method is also used to send control commands to control the operation of the battery thermal management system of electric construction machinery;

[0126] Electric construction machinery battery thermal management system, used for heating or cooling the battery of electric construction machinery;

[0127] Electric engineering machinery battery thermal management system, including: PTC heater;

[0128] PTC heaters are used as energy-consuming components to receive electrical energy recovered through energy recovery and convert it into heat energy.

[0129] Optionally, the electric construction machinery battery thermal management system further includes: a thermal management controller and a water-cooled unit; the thermal management controller is used to determine the operating mode of the electric construction machinery battery thermal management system based on the cell temperature, and the operating modes of the electric construction machinery battery thermal management system include a heating mode and a cooling mode; the thermal management controller is also used to control the electric construction machinery battery thermal management system to determine the operating modes of the water-cooled unit and the PTC heater based on the operating mode and the inlet temperature of the water-cooled unit, and the operating modes of the water-cooled unit and the PTC heater include a cooling mode, a self-circulation mode, a heating mode, and a shutdown mode.

[0130] The electric construction machinery battery thermal management system in this embodiment is used to implement the electric construction machinery battery protection method as described in the second embodiment, specifically including:

[0131] Send control commands to control the electric construction machinery battery thermal management system to determine the working mode of the electric construction machinery battery thermal management system based on the cell temperature. The working modes of the electric construction machinery battery thermal management system include heating mode and cooling mode.

[0132] Optionally, the operating modes of the electric construction machinery battery thermal management system include driving heating mode, charging heating mode, driving cooling mode and charging cooling mode;

[0133] The battery thermal management system for electric construction machinery determines its operating mode based on the cell temperature, including:

[0134] The battery thermal management system for electric construction machinery determines its operating mode based on the cell temperature and the operating status of the electric construction machinery.

[0135] Optionally, the battery thermal management system for electric construction machinery also includes a water-cooled unit;

[0136] The method also includes:

[0137] Send control commands to control the electric engineering machinery battery thermal management system to determine the working mode of the water-cooled unit and PTC heater based on the working mode and the inlet temperature of the water-cooled unit. The working modes of the water-cooled unit include cooling mode, self-circulation mode, heating mode and shutdown mode.

[0138] Optionally, the electric construction machinery battery thermal management system determines the operating mode of the water-cooled unit and the PTC heater based on the operating mode and the inlet temperature of the water-cooled unit, including:

[0139] The electric construction machinery battery thermal management system determines the operating mode of the water-cooled unit and PTC heater in the next operating stage based on the operating mode, the inlet temperature of the water-cooled unit, and the operating mode of the water-cooled unit and PTC heater in the previous operating stage.

[0140] This embodiment provides a specific structure for a battery thermal management system for electric construction machinery, as shown in Figure 3. It includes a battery, a vehicle controller, a thermal management controller, a water-cooled unit, and a PTC heater. The operating logic of the battery thermal management system in this embodiment can be referenced to the battery protection method for electric construction machinery described in the second embodiment.

[0141] The fifth embodiment of the present invention also proposes an electric engineering machinery, including the electric engineering machinery battery thermal management system described in the fourth embodiment.

[0142] The electric engineering machinery provided in this embodiment can be an electric road roller or an electric milling machine.

[0143] The electric construction machinery provided in this embodiment belongs to the same inventive concept as the electric construction machinery battery protection method or electric construction machinery battery thermal management system provided in the above embodiments of the present invention. It can execute the electric construction machinery battery protection method or electric construction machinery battery thermal management system provided in any of the above embodiments of the present invention, and possesses the corresponding functional modules and beneficial effects. Technical details not described in detail in this embodiment can be found in the specific processing content of the electric construction machinery battery protection method or electric construction machinery battery thermal management system provided in the above embodiments of the present invention, and will not be repeated here.

[0144] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0145] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For apparatus embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0146] The steps in the methods of the various embodiments of this application can be adjusted, merged, or deleted in order according to actual needs, and the technical features described in each embodiment can be replaced or combined.

[0147] The modules and sub-modules in the various embodiments of the present application's devices and terminals can be merged, divided, and deleted according to actual needs.

[0148] It should be understood that the disclosed terminals, devices, and methods can be implemented in other ways, given the several embodiments provided in this application. For example, the terminal embodiments described above are merely illustrative. For instance, the division of modules or sub-modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple sub-modules or modules may be combined or integrated into another module, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or modules, and may be electrical, mechanical, or other forms.

[0149] The modules or submodules described as separate components may or may not be physically separate. The components that constitute a module or submodule may or may not be physical modules or submodules; that is, they may be located in one place or distributed across multiple network modules or submodules. Some or all of the modules or submodules can be selected to achieve the purpose of this embodiment's solution, depending on actual needs.

[0150] Furthermore, the functional modules or sub-modules in the various embodiments of this application can be integrated into one processing module, or each module or sub-module can exist physically separately, or two or more modules or sub-modules can be integrated into one module. The integrated modules or sub-modules described above can be implemented in hardware or in the form of software functional modules or sub-modules.

[0151] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0152] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software unit executed by a processor, or a combination of both. The software unit can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0153] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0154] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of electrically protecting a battery of a construction machine, characterized by, The method comprises: determining the allowable regenerative power of the electric construction machinery battery according to the battery state parameters of the electric construction machinery battery, the battery state parameters including the battery capacity and the cell temperature; obtaining the demand braking power of the electric construction machinery, and when the demand braking power is greater than the allowable regenerative power, inputting part of the electric energy obtained by energy recovery into the electric construction machinery battery at the allowable regenerative power, and inputting the remaining part of the electric energy obtained by energy recovery into the energy consumption components of the electric construction machinery.

2. The method of claim 1, wherein, Further comprising: when the demand braking power is less than or equal to the allowable regenerative power, inputting all the electric energy obtained by energy recovery into the electric construction machinery battery; or, when the demand braking power is less than or equal to the allowable regenerative power, inputting part of the electric energy obtained by energy recovery into the energy consumption components of the electric construction machinery, and inputting the remaining part of the electric energy obtained by energy recovery into the electric construction machinery battery.

3. The method of claim 1, wherein, The method further comprises: determining the demand braking power of the electric construction machinery according to the kinetic energy, the gravitational potential energy component, the demand braking time, the rolling resistance and the demand braking distance of the electric construction machinery; The method further comprises: calculating the sum of the maximum power of the energy consumption components and the allowable regenerative power as the maximum regenerative braking power; when the demand braking power is greater than the maximum regenerative braking power, controlling the braking system of the electric construction machinery to output a braking torque to meet the braking demand.

4. The method of claim 1, wherein, Further comprising: when the cell temperature is in a preset limited driving temperature range, controlling the electric construction machinery to be parked; or, when the cell temperature is in a preset limited speed temperature range and the electric construction machinery battery is not being heated or cooled, controlling the electric construction machinery to be parked; or, when the cell temperature is in the limited speed temperature range and the electric construction machinery battery is being heated or cooled, limiting the output power of the electric construction machinery.

5. The method of claim 1, wherein, The method is also used to send control instructions to control the operation of the electric construction machinery battery thermal management system; The electric construction machinery battery thermal management system is used to heat or cool the electric construction machinery battery; The electric construction machinery battery thermal management system comprises a PTC heater; The PTC heater is used as the energy consumption component to receive the electric energy obtained by energy recovery and convert the electric energy into heat energy.

6. The method of claim 5, wherein, Further comprising: sending control instructions to control the electric construction machinery battery thermal management system to determine the working mode of the electric construction machinery battery thermal management system according to the cell temperature, the working mode of the electric construction machinery battery thermal management system including a heating mode and a cooling mode; The heating mode includes a driving heating mode and a charging heating mode, and the cooling mode includes a driving cooling mode and a charging cooling mode; The electric construction machinery battery thermal management system determines the working mode of the electric construction machinery battery thermal management system according to the cell temperature, which comprises: The electric engineering machinery battery thermal management system determines a working mode of the electric engineering machinery battery thermal management system according to the cell temperature and an operating state of the electric engineering machinery.

7. The method of claim 6, wherein, The electric engineering machinery battery thermal management system further comprises a water cooling unit. The method further comprises: sending a control instruction to control the electric engineering machinery battery thermal management system to determine a working mode of the water cooling unit and the PTC heater according to the working mode and an inlet water temperature of the water cooling unit, the working mode of the water cooling unit comprising a refrigeration mode, a self-circulation mode, a heating mode and a shutdown mode; The electric engineering machinery battery thermal management system determines a working mode of the water cooling unit and the PTC heater according to the working mode and an inlet water temperature of the water cooling unit, comprising: The electric engineering machinery battery thermal management system determines a working mode of the water cooling unit and the PTC heater in a next working stage according to the working mode, the inlet water temperature of the water cooling unit and the working mode of the water cooling unit and the PTC heater in a previous working stage.

8. An electrically powered construction machine battery thermal management system characterized by, comprising a vehicle controller and a PTC heater; The vehicle controller is configured to determine an allowable regenerative power of the electric engineering machinery battery according to a battery state parameter of the electric engineering machinery battery, the battery state parameter comprising a battery capacity and a cell temperature; acquire a required braking power of the electric engineering machinery, and when the required braking power is greater than the allowable regenerative power, input a part of electric energy acquired by energy recovery to the electric engineering machinery battery at the allowable regenerative power, and input a remaining part of the electric energy acquired by energy recovery to an energy consumption component of the electric engineering machinery. The PTC heater is configured to receive the electric energy acquired by energy recovery and convert the electric energy into heat energy as the energy consumption component.

9. The electrically powered construction machine battery thermal management system of claim 8, wherein, The electric engineering machinery battery thermal management system further comprises a thermal management controller and a water cooling unit. The thermal management controller is configured to determine a working mode of the electric engineering machinery battery thermal management system according to the cell temperature, the working mode of the electric engineering machinery battery thermal management system comprising a heating mode and a cooling mode. The thermal management controller is further configured to control the electric engineering machinery battery thermal management system to determine a working mode of the water cooling unit and the PTC heater according to the working mode and an inlet water temperature of the water cooling unit, the working mode of the water cooling unit and the PTC heater comprising a refrigeration mode, a self-circulation mode, a heating mode and a shutdown mode.

10. An electrically powered working machine, characterized in that comprising the electric engineering machinery battery thermal management system according to claim 8 or 9.

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