Electric vehicle battery cooling waterway cooling system and control method thereof

Abstract

The invention discloses an electric vehicle battery cooling waterway cooling system and a control method thereof, and belongs to the technical field of electric vehicle battery cooling. A water cooling machine in the system is connected with an input header pipe and an output header pipe, the input header pipe is provided with a speed regulation water pump, and the input header pipe and the output header pipe are communicated through a two-position four-way reversing valve; the input header pipe and the output header pipe are connected to the two ends of a water way of the battery pack system, temperature probes are arranged in batteries of the battery pack system, a three-way valve a and a three-way valve b are arranged between every two adjacent batteries, and proportional valves are arranged between water outlets of the batteries and the water inlet end of the three-way valve a. The temperature probe is electrically connected with the signal input end of the water path controller, and the signal output end of the water path controller is electrically connected with control switches of the water cooling machine, the speed regulating water pump, the two-position four-way reversing valve, the proportional valve, the three-way valve a and the three-way valve b. Various temperature difference working conditions of the battery cooling system can be effectively controlled and adjusted, and the market application limitation of the electric vehicle is overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of electric vehicle battery cooling waterway cooling system and control method thereof, belong to electric vehicle battery cooling technical field. BACKGROUND

[0002] The consistency of the capacity, internal resistance, voltage and working temperature of the battery cell in the electric vehicle battery is closely related to the life and performance of the battery system. Currently, the capacity and internal resistance detection monitoring and management are unified by BMS, and the control strategy and management means have been relatively perfect. Although the battery cell temperature difference management is also managed by BMS, the management means is relatively less, and only through centralized heating or centralized cooling, if heating is carried out by PTC heating film, it is difficult to control, only water cooling and water heating can control the heat exchange effect by increasing or decreasing water flow and water cooling unit and water heating PTC start-stop control, the means is relatively single, but it is difficult to accurately control the temperature difference consistency between the package and the package.

[0003] In the prior art, the electric vehicle factory can only select the initial design of water route series-parallel form and the shielding and heat preservation treatment of battery system and pipeline to achieve the ideal heat management theoretical value. The existing electric vehicle cooling system technology often focuses on the threshold value comparison and judgment of battery inlet and outlet water temperature difference and theoretical heat exchange temperature difference, multi-mode combination of heat exchange form, liquid cooling circuit pressure detection control, refrigerant pipeline or cold air cooling function integration of driving cab air conditioning refrigeration system, multi-branch parameter measurement, multi-branch cooling manifold quick release structure, multi-branch flow regulating valve and simple branch regulating function as the main innovation points. However, the problems such as how to balance the cooling effect of battery cooling system water cooling pipeline series-parallel, cooling liquid flow control, temperature increment problem of series-parallel battery package in branch, pipeline layout and length difference and flow resistance difference of different branches, temperature increment problem of different regions of battery cell in package, parallel branch flow difference and cooling effect difference problem, water pump energy saving and consumption control problem, temperature difference problem in different seasons or a day and temperature difference problem of different regions in battery system affected by light preservation and ventilation, and the influence of cell temperature difference and battery performance and life caused by cooling effect difference are not involved, which will cause certain performance and regional environment limitation in electric vehicle market application, and the use flexibility is limited. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the defects of the prior art, and to provide an electric vehicle battery cooling waterway cooling system and control method thereof, which can effectively control and adjust various temperature difference conditions of the battery cooling system, and overcome the application limitation of electric vehicle market.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is:

[0006] In a first aspect, the present application provides a cooling system for an electric vehicle battery cooling water circuit, comprising a water chiller, an input main pipe and an output main pipe connected to the water chiller, a speed regulating water pump arranged on the input main pipe, a two-position four-way reversing valve arranged between the input main pipe and the output main pipe to realize reversing, the input main pipe and the output main pipe connected to both ends of a water circuit of a battery pack system, the battery pack system comprising a plurality of batteries, a temperature probe arranged in each battery, a three-way valve a and a three-way valve b arranged between two adjacent batteries, a water outlet of a first battery connected to a water inlet end of the three-way valve a, two water outlet ends of the three-way valve a connected to the output main pipe and a water inlet end of the three-way valve b respectively, the input main pipe connected to a water inlet end of a second battery and another water inlet end of the three-way valve b respectively, a water outlet end of the three-way valve b connected to a water inlet of a third battery, and a proportional valve arranged between the water outlet of the battery and the water inlet end of the three-way valve a; the temperature probe electrically connected to a signal input end of a water circuit controller, and a signal output end of the water circuit controller electrically connected to control switches of the water chiller, the speed regulating water pump, the two-position four-way reversing valve, the proportional valve, the three-way valve a and the three-way valve b.

[0007] The proportional valve comprises a ball valve or a two-position single-way valve.

[0008] The valve body of the reversing valve and the two-position four-way reversing valve is switched or driven by an electromagnetic coil or a motor.

[0009] A BMS slave control is arranged in the battery, the BMS slave control sends a temperature signal of the temperature probe to a BMS master control through a sub-network CAN, and the BMS master control sends the temperature signal to the water circuit controller through a CAN line.

[0010] A flow meter is arranged at a water inlet or a water outlet of the battery, and the flow meter is electrically connected to a signal input end of the water circuit controller.

[0011] The water circuit controller is electrically connected to a Tbox and a data recorder.

[0012] In a second aspect, the present application provides a control method of an electric vehicle battery cooling water circuit cooling system, comprising the following steps: a temperature probe sends the real-time collected battery cell temperatures of all batteries in a battery pack to a water circuit controller, the water circuit controller generates a control instruction according to the received battery cell temperatures for temperature strategy determination, and sends the control instruction to a water cooler to control its working mode; in the initial stage of system operation, the pipe layout state meeting the demand at this time can be selected according to the temperature parameters and set parameters for preliminary operation, and it is not necessary to start from the highest end or the bottom end mode and step by step across every time, so that the efficiency of mode switching adjustment is improved. At the same time, the water circuit controller sends the control instruction to a speed regulating water pump to control the water circuit flow, to a two-position four-way reversing valve to realize water circuit reversing, and to a proportional valve, a three-way valve a and a three-way valve b to realize the switching of water circuit parallel, mixed connection and series connection states.

[0013] The temperature strategy determination adopts battery overall temperature determination, specifically comprising:

[0014] a. When the overall temperature is low according to the comprehensive determination of the battery cell temperatures, the water circuit controller adopts a one-level lower water circuit cooling mode, controls the proportional valve, the three-way valve a and the three-way valve b to adjust the water circuit connection state according to the trend switching from parallel to mixed connection and then to series connection, and simultaneously reduces the speed regulating water pump flow power. If the overall temperature is still low after the operation effect is always reduced to the series connection mode, the water cooler adopts an intermittent working mode, only water circulation and fan heat dissipation of the water cooler are performed without compressor refrigeration. If the overall temperature is still low after the operation effect, the water cooler is temporarily stopped to wait for the battery temperature to gradually rise, and the water pump is also temporarily stopped to assist the battery temperature rise;

[0015] b. When the overall temperature is high according to the comprehensive determination of the battery cell temperatures, the water circuit controller adopts a one-level higher water circuit cooling mode, controls the proportional valve, the three-way valve a and the three-way valve b to adjust the water circuit connection state according to the trend switching from series connection to mixed connection and then to parallel connection, and simultaneously increases the speed regulating water pump flow power. If the overall temperature is still high after the operation effect is always increased to the parallel connection mode, the water cooler adopts a high-efficiency refrigeration mode, the refrigeration compressor of the water cooler improves the operation speed for continuous work, and the water cooler heat dissipation fan synchronously improves the operation speed. If the overall temperature is still high after the operation effect, the speed regulating water pump is further strengthened to improve the water flow by increasing the speed.

[0016] The temperature strategy determination adopts battery temperature difference range determination, specifically comprising:

[0017] c. When the local temperature is low according to the comprehensive determination of the battery cell temperatures, that is, the input end temperature of the water circuit system is low, and the output end temperature is arranged in ascending order, resulting in a large temperature difference, the water circuit controller adjusts the two-position four-way reversing valve to make the water circuit flow in the opposite direction, so that the low-temperature input end becomes the output end, and the temperature of the original input end is raised by step-by-step temperature rise between the battery packs.

[0018] d. When the local temperature is determined to be too high according to the temperature of the battery cell, the output temperature of the waterway system is too high, and the temperature of the input end is arranged in a descending order, resulting in a large temperature difference, the waterway controller adjusts the two-position four-way reversing valve to reverse the flow of the waterway, changes the output end with high temperature into the input end, and effectively cools the original output end temperature by using the principle that the cooling effect of the inflow end coolant is better due to its lower temperature;

[0019] e. When the local temperature is determined to be too high according to the temperature of the battery cell, the output temperature of the waterway system is too high, and the temperature of the input end is arranged in a descending order, resulting in a large temperature difference, the waterway controller adjusts the two-position four-way reversing valve to reverse the flow of the waterway, changes the output end with high temperature into the input end, and effectively cools the original output end temperature by using the principle that the cooling effect of the inflow end coolant is better due to its lower temperature;

[0020] When the local temperature is determined to be too high according to the temperature of the battery cell, the output temperature of the waterway system is too high, and the temperature of the input end is arranged in a descending order, resulting in a large temperature difference, the waterway controller adjusts the two-position four-way reversing valve to reverse the flow of the waterway, changes the output end with high temperature into the input end, and effectively cools the original output end temperature by using the principle that the cooling effect of the inflow end coolant is better due to its lower temperature;

[0021] When the local temperature is determined to be too high according to the temperature of the battery cell, the output temperature of the waterway system is too high, and the temperature of the input end is arranged in a descending order, resulting in a large temperature difference, the waterway controller adjusts the two-position four-way reversing valve to reverse the flow of the waterway, changes the output end with high temperature into the input end, and effectively cools the original output end temperature by using the principle that the cooling effect of the inflow end coolant is better due to its lower temperature;

[0022] When the local temperature is determined to be too high according to the temperature of the battery cell, the output temperature of the waterway system is too high, and the temperature of the input end is arranged in a descending order, resulting in a large temperature difference, the waterway controller adjusts the two-position four-way reversing valve to reverse the flow of the waterway, changes the output end with high temperature into the input end, and effectively cools the original output end temperature by using the principle that the cooling effect of the inflow end coolant is better due to its lower temperature;

[0023] When the irregular temperature difference between the packages is eliminated, and the irregular temperature difference exists in the package or the internal temperature difference of the partial package exists, and the temperature difference in the package meets the rule of low inlet temperature and high outlet temperature, the proportional valve can be used to concentrate the water flow to the battery package with large temperature difference, and the program-controlled reversing valve can be used to change the water flow direction to the battery package with large internal temperature difference.

[0024] The application provides an electric vehicle battery cooling water circuit cooling system and a control method thereof.

[0025] The water inlet or the water outlet of the battery is provided with a flow meter, and the flow meter is electrically connected with a signal input end of a water circuit controller, so that accurate control of the flow of the cooling liquid in different branches can be realized.

[0026] The water circuit controller is electrically connected with a Tbox and a data recorder, and has the functions of collecting and analyzing the working conditions and the environmental temperature, the battery system and the vehicle running parameters, saving and uploading, and continuously analyzing, optimizing and reversely iterating and improving. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a schematic diagram of a battery system cooling circuit in series and parallel form of the prior art.

[0028] Figure 2 It is a schematic diagram of a cooling circuit connection adjustable scheme in the electric vehicle battery cooling water circuit cooling system.

[0029] Figure 3 It is a control principle diagram of the water circuit controller in the application.

[0030] Figure 4 is the battery system temperature abnormal position determination logic diagram of the present application;

[0031] Figure 5 is the waterway control logic flow chart of the present application. DETAILED DESCRIPTION

[0032] The present application will be further described below in conjunction with the accompanying drawings, and the following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0033] Example 1

[0034] The existing battery waterway connection state: taking a four-pack battery system as an example, it is divided into three ways of series connection, parallel connection and mixed connection, the water cooling ports of each battery pack are A and B without distinction of input and output, but in order to facilitate description, A is always the initial state input, B is always the initial state output, X is the initial state input total water pipe, Y is the initial state output total water pipe, X1-X4 are the initial state input total water pipe connecting the corresponding battery pack A port, and Y1-Y4 are the initial state output total water pipe connecting the corresponding battery pack B port, the pipe connecting the B port of the corresponding battery with the A port of the next battery is the inter-pack series connection pipe, and details are shown in Figure 1 .

[0035] 1. Series connection: the waterway defaults to flow into the 1A input port of the battery 1 from the X input total pipe, after the battery 1 internal water cooling heat exchange plate cools the battery cell, the heat is taken away from the 1B port, and then the water flows into the 2A input port of the battery 2 through the inter-pack series connection pipe from 1B to 2A, and then cools the internal battery cell, and then flows out from the 2B port into the 3A input port of the battery 3, and then flows out from the 4B output port of the battery 4, and then flows back to the battery water cooler through the output total pipe Y, to complete a complete 4-battery inter-pack series connection loop, and details are shown in Figure 1 A diagram.

[0036] The advantage of the series connection loop is that the loop structure is simple, and the water pump only needs to overcome the flow resistance of four packs, and the flow is greater than the heat dissipation flow demand of a single battery pack, so the flow and power requirements of the water pump are the smallest. But the disadvantage of the series connection loop is that the water temperature is increased after passing through each battery pack, and the cooling effect of the next pack is decreased, because the temperature difference between the cooling liquid and the battery cell is reduced when the internal battery cell of the rear pack exchanges heat, and the heat exchange effect is poor, and the battery temperature is easily higher than that of the previous pack, and the cooling effect of the last pack is the worst.

[0037] 2, Parallel: the water path defaults from the X input main pipe through the respective X output branch pipe, flows into the respective A port of the battery 1 to the battery pack 4, and flows out from the respective B port through the respective Y branch pipe into the output Y main pipe, and flows back to the battery water cooler, completing a complete 4-battery-pack interconnection loop, the X and Y main pipes need to be about 4 times the sectional area of the branch pipe, see the C diagram of Figure 1 .

[0038] The advantage of the interconnection loop is that there is no problem of temperature increment between packs, and the inflow water temperature of each battery pack is consistent with the initial water temperature. However, the disadvantage of the interconnection loop is that each pack requires a nominal flow, and the total flow demand is large, so the flow and power of the pump need to be increased, the low-voltage power consumption will increase, and because the loop is not serial, the flow of each branch is different due to the flow resistance difference caused by the layout and length of the pipeline, resulting in actual flow inequality and different cooling effects and actual cell temperature.

[0039] 3, Mixed connection: the water path defaults from the X input main pipe through the X1 output branch pipe into the 1A input port of the battery 1, from the 1B output port into the 2A input port of the battery 2, and from the 2B output port through the Y2 output branch pipe into the Y output main pipe, forming a serial connection loop, while the battery 3 and the battery 4 form another serial connection loop, and the two loops are connected in parallel to form a mixed connection loop with series and parallel connection, wherein the sectional area of the X and Y main pipes is not less than 2 times the sectional area of the branch pipe, see the B diagram of Figure 1 .

[0040] The advantage of the mixed connection is that the water pump flow is relatively controllable, which is half of the flow demand in the pure parallel connection case, and the temperature increment between the battery packs is about half of the last pack in the serial connection mode, and the overall performance is relatively balanced. However, the disadvantage of the mixed connection is that there is still a temperature increment between the packs, and there is a temperature difference caused by the flow resistance difference between the branches due to the layout and length, and the flow demand is also about twice that of the serial connection.

[0041] In summary, each connection method has its own advantages and disadvantages, and each cooling system is difficult to have universality under different working conditions and environmental temperature conditions, and vehicles often use one of several schemes, which cannot be adjusted flexibly according to different environments and working conditions, and the advantages of several connection methods are taken to make up for the shortcomings.

[0042] The application discloses a battery cooling water path cooling system for an electric vehicle, which comprises a cooling pipeline part and a program control part. Figure 2 and Figure 3As shown, still taking the four-battery pack system as an example, the initial state is also default X as the input header, Y as the output header, and further includes a water cooler, the water cooler is connected with the input header and the output header, and a speed regulating water pump is arranged on the input header. A is an initial state input port of the battery water cooling plate, B is an output port, X1-X4 are initial state input branch pipes, and Y1-Y4 are initial state output branch pipes. The cross-sectional area of the X and Y headers is more than 4 times the cross-sectional area of a single branch pipe. The input header and the output header are communicated through a two-position four-way reversing valve to realize reversing, and the flow direction of water can be changed to change the input and output initial states under control. The control mode of the reversing valve can be electric control or pneumatic control, which is not limited. The input header and the output header are connected at both ends of the water path of the battery pack system, and the battery pack system includes a plurality of batteries.

[0043] A three-way valve a and a three-way valve b are arranged between two adjacent batteries, and the three-way valve a and the three-way valve b are program-controlled flow limiting three-way valves with opening degree signal feedback. The water outlet of the previous battery is connected with the water inlet end of the three-way valve a, the two water outlet ends of the three-way valve a are respectively connected with the output header and one water inlet end of the three-way valve b, the input header is connected with the water inlet end of the first battery and the other water inlet end of the three-way valve b through the input branch pipe, and the water outlet end of the three-way valve b is connected with the water inlet of the next battery. In the present application, a flow meter can be selectively installed on each branch, and the type of the flow meter is not limited. The flow meter can be installed at the interface position near the A or B port, and the specific installation point is not limited by the arrangement space. However, the flow direction needs to be programmed and calibrated. In the present example, the flow meter is arranged at the A port of each battery for the convenience of drawing display. A proportional valve is arranged near the water cooling port of each battery for flow limiting and adjusting. The proportional valve can be a ball valve or a two-position single-way valve, and the form is not limited. The control mode of the proportional valve is electric control with execution feedback, which can collect the opening value of the valve and realize closed-loop positive feedback control according to the program control parameter opening requirement. The position of the proportional valve is determined according to the specific arrangement space. In the present example, the proportional valve is arranged at the B port near each battery pack according to the drawing requirement.

[0044] The temperature acquisition in the application is realized by arranging temperature probes in the battery, the water path controller needs to be previously placed in the battery system, the number of battery packs in the system and the number in the system, the number of probes contained in each pack, and the number, so as to know which temperature probe belongs to which pack, to determine whether the temperature difference in each pack is out of the standard, and whether there is a significant temperature difference between the packs. At the same time, the arrangement position of each probe in the pack and the corresponding probe number and the sequence relationship of the cooling liquid flow channel of the battery pack are placed, so as to know which pack, which part in the battery, which area in the flow direction, close to or far from the input or output port according to a certain probe number. The temperature high limit value range allowed by the battery system and the maximum and minimum temperature difference allowed range of the battery cell are placed, so as to determine whether the collected temperature value is too high or too low, or whether the maximum and minimum temperature values in all battery cells are out of the standard. The water path connection mode supported by the system and the series-parallel relationship and the relative position of each battery pack in different modes are placed, so as to define the series-parallel relationship and the upstream and downstream relationship of the packs in different modes, see Figure 4 .

[0045] In addition, the application adds parameter matching calibration and big data analysis fine functions on the basis of the above. The flow rate monitoring and regulation of each branch, the opening value monitoring and regulation of the proportional valve, the monitoring and regulation of high and low temperature and temperature difference, the setting and optimization adjustment of the proportional valve opening limit value range, the requirement of battery cell at different temperatures on the cooling liquid flow, the control requirement of the temperature difference of the battery pack in and out of the water on the cooling effect, the working temperature range of the battery system, the setting and calibration of the PID parameters used for temperature regulation, the charging and discharging heat statistical analysis and estimation, the cooling effect and power consumption performance of different regions and different seasons, the adaptability of the cooling performance of different water path modes to different environments and working conditions, the flow resistance difference analysis and compensation strategy regulation of different pipe arrangements on different batteries and cooling branches, etc. are all the contents that need to be matched and calibrated and continuously tracked, collected, analyzed and optimized.

[0046] The application records and saves the CAN of the real-time battery system temperature parameters, working conditions and cooling system working parameters and mode states of the vehicle through the Tbox+data recorder+big data platform analysis mode, and transmits and uploads them remotely, and uses the big data analysis advantage to perform parameter optimization calculation, continuously optimizes and iterates the required calibration quantity, and reversely recalibrates the related vehicle, so as to achieve better cooling effect and energy saving effect.

[0047] At the same time, the water path mode switching is monitored by the water path controller in real time, accurately judges the moment when the vehicle is in a low speed and low power output state, such as deceleration braking or low speed running and parking, and performs timely switching when the real-time heat of the battery system is not large, which is more beneficial to the smoothness of the vehicle.

[0048] For example, Figure 2 As shown, the application can realize flexible adjustment of the pipeline series-parallel hybrid structure through the three-way valve of the cooling pipeline, realize forward and reverse flow direction control of the water pipeline through the two-position four-way reversing valve, and the valve body of the reversing valve or two-position four-way valve can be switched by an electromagnetic coil or a driving motor such as a stepper motor. Without considering the change of water pump power consumption, from the refrigeration performance (heat transfer) effect, considering the influence of water flow size and inter-pack temperature rise increment and the improvement effect of temperature difference suppression of reverse flow, under the premise of the same equipment condition and ensuring the consistency of the flow of each branch, the refrigeration effect of the three connection states is in the order of series < hybrid < parallel, that is, the series effect is the weakest, and the parallel effect is the strongest. From series to hybrid to parallel is defined as the upgrade of the refrigeration mode in turn, and vice versa. The specific control mode of each mode is as follows:

[0049] 1. Series: The water pipeline defaults from the X input main pipe to flow into the X1 branch pipe, and then flows into the 1A input port of the battery 1 through the flowmeter. After the battery 1 is cooled by the internal water-cooled heat exchange plate, the heat is taken away from the 1B port. After passing through the proportional valve with flow limiting effect, the three-way valve is guided to enter the 2A input port of the battery 2 along the arrow direction from 1B to 2A. At this time, the three-way valve flow direction Y1 branch pipe outlet is closed by process control. The cutoff line in the three-way valve schematic diagram is used as a cutoff schematic, and the direction of the three-way valve connected to the 1B port is the common end of the valve in this three-way position. The common end of the three-way valve is indicated by a dot.

[0050] Similarly, the three-way valve at the 2A port position is turned to enter the 2A inlet, but the three-way valve from the X2 branch pipe to the 2A port is cut off so that the X main pipe water flow cannot directly enter the 2A port through the three-way valve. It must first enter 2A from 1B. After the battery 2 is cooled, it enters the 3A input port of the battery 3 from the 2B outlet, and continues to the 4B output port of the battery 4. After flowing out through the output main pipe Y, it returns to the battery water cooler, completing a complete 4-battery inter-pack series loop. During the process, all three-way valve controls remain the same as between battery 1 and battery 2. The two-position four-way reversing valve at the X and Y main pipes is in the initial state of default X into Y. See Figure 2 A diagram.

[0051] 2, Parallel: the waterway defaults from X input main pipe through each X branch pipe, flows into each A port of battery 1 to battery pack 4, wherein X1 branch pipe can directly flow into 1A after passing through the flowmeter, and X2 to X4 branch pipes all need to pass through the process control three-way valve first, pass through each flowmeter in the arrow direction and then enter the A port of the corresponding battery pack, and from each B port, pass through the process control flow limiting proportional valve, flow out and be guided by the process control three-way valve at each Y branch pipe to each Y branch pipe and then be collected to Y main pipe, and from each B port, like the Y branch pipe three-way valve at the A port of the next battery pack, is cut off in the direction of the next battery pack, can only be diverted to flow to each Y branch pipe and then flow into the output Y main pipe, flow back to the battery water cooler, complete a complete 4-battery pack parallel loop, X and Y main pipes need to be about 4 times the sectional area of the branch pipe, and X and Y main pipes pass through the process control two-position four-way valve. See the C diagram of Figure 2 .

[0052] 3, Mixed connection: the waterway defaults from X input main pipe through X1 branch pipe and passes through the flowmeter to enter the 1A input port of battery 1, flows through the process control flow limiting proportional valve from the 1B output port, passes through the process control three-way valve at the intersection of the overpipe and Y1 output branch pipe between 1B and 2A ports, the valve cuts off the direction of 1B flowing through Y1 branch pipe, so that the water flow from 1B can only flow through 2A direction, and the process control three-way valve at the intersection of the overpipe and X2 branch pipe keeps cutting off the water flow from X2 to 2A direction, only the water flow from 1B to 2A direction is needed, flows through the flowmeter of battery 2 to cool battery 2, and after passing through the process control flow limiting proportional valve of battery 2 from the 2B output port, at the process control three-way valve at the intersection of 2B and 3A overpipe and Y2 output branch pipe, the water flow is controlled to pass through Y2 branch pipe and then enter Y output main pipe, forming a series loop.

[0053] And similarly, battery 3 and battery 4 form another series loop, and the two series loops are connected in parallel to form a mixed loop with series and parallel. Meanwhile, the process control three-way valve at the intersection of 2B to 3A overpipe and X3 branch pipe keeps the water flow from X3 branch pipe to 3A direction and cuts off the water flow from 2B direction. X and Y main pipes pass through the process control two-way valve, see the B diagram of Figure 2 .

[0054] The program control part is shown in Figure 3 , the BMS slave control is arranged in the battery, the BMS slave control sends the temperature signal of the temperature probe to the BMS master control through the sub-network CAN, and then the BMS master control sends the temperature signal to the road controller through the CAN line. The flowmeter is electrically connected with the signal input end of the waterway controller, and the signal output end of the waterway controller is electrically connected with the water cooler, the speed regulating water pump, the two-position four-way valve, the proportional valve, the three-way valve a and the three-way valve b. According to the resource condition of the vehicle controller, the software and hardware functions of the waterway controller of the application can be selectively integrated into the existing controller, such as the BMS or water cooler group controller to realize the functions of the waterway controller.

[0055] The control principle of the application is that the water path controller collects the flow sensor parameters of each battery water path branch (as needed, if there is no flow sensor, the positive feedback regulation is performed by relying on the temperature regulation effect, which is not conducive to the optimization of parameters using historical data, resulting in large regulation hysteresis) to obtain accurate flow of each branch. The water path controller adjusts the cooling liquid flow of the corresponding branch through hard-wired control of the proportional valve, controls the flow direction of the cooling liquid in the three-way pipeline through hard-wired control of three-way valve a and three-way valve b, controls the direction of the water flow in the main pipeline through hard-wired control of the two-position four-way reversing valve, can realize the function that the pump water flow direction does not change, but the liquid flow direction in the pipeline is reversed, controls the speed of the speed-regulating water pump through the hard-wired PWM signal, collects the temperature values of the cells in each battery pack through CAN line, the temperature values are collected by the cell temperature sensors in the pack and collected by the BMS slave control and sent to the BMS master through the sub-network CAN, sent to the water path controller by the BMS master through CAN, connected to the CAN data recorder through CAN and all CAN message information is saved in real time, connected to the water cooling unit through CAN to control the water cooling machine to work and stop, and details are shown in Figure 3 .

[0056] Embodiment 2

[0057] This embodiment discloses a control method based on the battery cooling water path cooling system of the electric vehicle of embodiment 1, as shown in Figure 5 The BMS master sends all the cell temperatures in the battery pack collected by the BMS slave control through CAN message, the water path controller receives and performs temperature strategy determination, and controls the corresponding valves, water pumps and battery water cooling machines to change the water path and adjust the flow rate and refrigeration power. When performing temperature determination, mainly according to the comparison between the received temperature information and the set parameters, the determination of whether the temperature range exceeds the upper and lower limits, and the determination of whether the temperature difference extreme value in the system, the temperature difference extreme value in the pack, the temperature difference extreme value between packs and the temperature interval exceed the standard and confirm the temperature high-low comparison relationship. This embodiment is mainly applied to temperature range determination: mainly divided into two aspects of overall low temperature and overall high temperature.

[0058] A. When the overall temperature is low: the water path controller adopts a one-level water path refrigeration mode to execute, controls the corresponding three-way valve a and three-way valve b to adjust the water path connection state, realizes the weakening of the refrigeration effect, and synchronously reduces the water pump flow power to realize the effect of energy saving and consumption reduction. If it is always reduced to a series mode, the overall temperature is still low, the water cooling machine adopts an intermittent working mode, only performs water circulation and fan heat dissipation of the water cooling machine without performing compressor refrigeration, if the temperature still does not obviously rise, the water cooling machine is temporarily stopped to wait for the battery temperature to gradually rise, and the speed-regulating water pump is also temporarily stopped to assist the battery temperature rise.

[0059] B. When the overall temperature is too high: the water circuit controller adopts the cooling mode of upgrading the water circuit one level, controls the corresponding three-way valve a and three-way valve b to adjust the water circuit connection status to achieve an enhanced cooling effect, and simultaneously increases the water pump flow power to increase the coolant flow effect. If the overall temperature is still too high when it is upgraded to the parallel mode, the water cooler will adopt the high-efficiency cooling mode through CAN communication, that is, the refrigeration compressor of the water cooler will increase the operating speed and continue to work, and the cooling fan of the water cooler will increase the operating speed simultaneously. If it still cannot effectively cool down and quickly control it within a reasonable temperature range, the water pump will further increase the speed to increase the water flow, and adopt intermittent peak speed power operation.

[0060] In addition, the present invention focuses on explaining the cooling strategy control, and can also be applied to battery water heating in extremely low temperature environments. The battery water heating strategy in extremely low temperature environments is implemented according to the opposite control strategy, that is, when the temperature is low, the heating is started or the heating power and duration are increased and the water mode is upgraded to one level; when the temperature is high, the heating power and duration are reduced and the water mode is downgraded to one level.

[0061] Example 3

[0062] This embodiment discloses a control method based on the electric vehicle battery cooling water circuit cooling system of embodiment 1, such as Figure 5 As shown, the BMS master sends the cell temperatures of all battery packs collected by the BMS slaves via CAN messages. After receiving the messages, the water circuit controller determines the temperature strategy and controls the corresponding valves, water pumps, and battery water coolers to change the water circuits and adjust the flow rate and cooling power. When making temperature judgments, it is mainly based on comparing the received temperature information with the set parameters to determine whether the temperature range exceeds the upper and lower limits, and to determine whether the temperature difference extremes in the system, the temperature difference extremes within the pack, the temperature difference extremes between packs, and the temperature range exceed the standards and confirm the temperature comparison relationship. This embodiment is mainly used for temperature difference range judgment: it is mainly divided into two aspects: local low temperature and local high temperature.

[0063] A. When the local temperature is low: the temperature of the input end of the water system is low, and the temperature tends to increase in order toward the output end, resulting in a large temperature difference. The water controller adjusts the two-position four-way reversal valve to reverse the flow of water, turning the low-temperature input end into the output end, and using the step-by-step temperature rise between the compartments to raise the temperature of the original input end.

[0064] B. When the local temperature is too high: When the temperature of the output end of the water system is too high, and the temperature tends to descend in descending order toward the input end, resulting in a large temperature difference, the water controller adjusts the programmable two-position four-way reversing valve to reverse the flow of water, turning the high-temperature output end into the input end, and effectively cooling the original output end temperature by using the principle that the coolant temperature at the inflow end is lower and the cooling effect is better.

[0065] C. Irregular inter-package temperature difference: When the local temperature is too low or too high, it is an irregular temperature difference between packages, such as local poor air circulation leading to high temperature, or cold wind blowing leading to too low temperature in some packages, or unilateral sun exposure leading to local temperature deviation, etc. It may not meet the ascending or descending order rule according to the water flow direction, and simply relying on reversing valve to change the water flow direction may not effectively solve the problem of irregular temperature difference between packages. Therefore, the method of adjusting the water connection structure is adopted.

[0066] C1. Mixed connection selection: When several temperature deviation packages can be completely put into one or several branches in mixed connection form, and there is no normal temperature range package in the branch to affect the independent cooling of the temperature deviation package, the mixed connection method can be adopted by program control, and the water proportioning valve of the package with temperature difference in the normal range is controlled by program control. The pipe opening of the proportional valve is reduced to limit the flow of the cooling liquid, so that more cooling liquid passes through the branch with high temperature to form a difference in refrigeration effect for temperature difference reverse adjustment, and the opening feedback value of the proportional valve is collected. The opening value is adjusted according to the temperature cooling control effect until the system temperature difference is effectively controlled and restored to the normal temperature difference range.

[0067] C2. Parallel selection: Similarly, when several temperature deviation packages cannot be completely put into one or several branches in mixed connection form, and there are normal temperature range packages in the branch to affect the independent cooling of the temperature deviation package, the parallel method is needed for program control. All packages are independently cooled by water control, and the water proportioning valve of the package with temperature difference in the normal range is controlled by program control. The pipe opening of the proportional valve is reduced to limit the flow of the cooling liquid, so that more cooling liquid passes through the branch with high temperature to form a difference in refrigeration effect for temperature difference reverse adjustment, and the opening feedback value of the proportional valve is collected. The opening value is adjusted according to the temperature cooling control effect until the system temperature difference is effectively controlled and restored to the normal temperature difference range.

[0068] C3. Reversing selection: When the irregular temperature difference between the packages is eliminated, and there is an irregular temperature difference in the package or some packages have internal temperature difference, and the internal temperature difference meets the rule of low inlet temperature and high outlet temperature, the proportional valve can be used to concentrate the water flow to cool the battery package with large temperature difference, and the reversing valve can be used to change the water flow direction to balance the internal temperature of the battery package with large internal temperature difference.

[0069] By the control method, the temperature increment problem between the series battery packs in the branch, the cooling effect difference problem caused by the pipeline layout, length difference and flow resistance difference of different branches, the temperature increment problem between the battery cells in different areas in the pack, the flow difference and cooling effect difference problem of the parallel branches, and the temperature difference problem caused by the large temperature difference in different seasons or in a day and the temperature difference caused by the light insulation and ventilation difference in different areas in the battery system can be solved.

[0070] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make some improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. An electric vehicle battery cooling water circuit cooling system, characterized by: The water cooler comprises a water cooler, an input manifold and an output manifold are connected to the water cooler, a speed regulating water pump is provided on the input manifold, the input manifold and the output manifold are connected to each other through a two-position four-way reversing valve to achieve reversal, the input manifold and the output manifold are connected to both ends of the water path of the battery pack system, the battery pack system comprises a plurality of batteries, a temperature probe is provided in the battery, a three-way valve a and a three-way valve b are provided between two adjacent batteries, the water outlet of the preceding battery is connected to the water inlet end of the three-way valve a, and the two water outlet ends of the three-way valve a are connected to the water inlet end of the input The outlet main pipe is connected to one water inlet end of the three-way valve b, the input main pipe is respectively connected to the water inlet end of the first battery and the other water inlet end of the three-way valve b, the water outlet end of the three-way valve b is connected to the water inlet of the next battery, and a proportional valve is provided between the water outlet of the battery and the water inlet end of the three-way valve a; the temperature probe is electrically connected to the signal input end of the water circuit controller, and the signal output end of the water circuit controller is respectively electrically connected to the control switches of the water cooler, speed regulating water pump, two-position four-way reversing valve, proportional valve, three-way valve a, and three-way valve b.

2. The electric vehicle battery cooling water circuit temperature reduction system according to claim 1, characterized in that: The proportional valve includes a ball valve or a two-position one-way valve.

3. The electric vehicle battery cooling water circuit temperature reduction system according to claim 1, characterized in that: The valve bodies of the reversing valve and the two-position four-way reversing valve are switched by electromagnetic coil control or by a driving motor control.

4. The electric vehicle battery cooling water circuit temperature reduction system according to claim 1, characterized in that: The battery is provided with a BMS slave controller, which collects the temperature signal of the temperature probe and sends it to the BMS master controller via the subnet CAN, and then the BMS master controller sends it to the water circuit controller via the CAN line.

5. The electric vehicle battery cooling water circuit temperature reduction system according to claim 1, characterized in that: The water inlet or outlet of the battery is provided with a flow meter, and the flow meter is electrically connected to the signal input end of the water circuit controller.

6. The electric vehicle battery cooling water circuit temperature reduction system according to claim 1, characterized in that: The waterway controller is electrically connected to a Tbox and a data recorder.

7. A control method for the electric vehicle battery cooling water circuit temperature reduction system according to any one of claims 1 to 6, characterized in that: The following steps are involved: The temperature probe collects the real-time cell temperatures of all batteries in the battery pack and sends them to the water circuit controller. The water circuit controller determines the temperature strategy based on the received cell temperatures and generates control instructions. The control instructions are sent to the water chiller to control its working mode, to the speed-regulating water pump to control the water flow, to the two-position four-way reversing valve to realize water circuit reversal, and to the proportional valve, three-way valve a, and three-way valve b to realize the switching of the water circuit parallel, mixed and series connection states.

8. The control method of the electric vehicle battery cooling water circuit temperature reduction system according to claim 7, characterized in that: The temperature strategy is determined by the overall battery temperature, including: a. When the overall temperature of the battery cell is judged to be low, the water circuit controller adopts the cooling mode of the water circuit that is lowered by one level. The proportional valve, three-way valve a and three-way valve b are controlled to adjust the water circuit connection state according to the trend of parallel to mixed connection and then to series connection, and the flow rate and power of the speed regulating water pump are simultaneously reduced. If the overall temperature is still low after the operation is reduced to the series mode, the water cooler is controlled to adopt intermittent working mode, which only performs water circulation and fan heat dissipation of the water cooler without compressor cooling. If the overall temperature is still low, the water cooler is controlled to be temporarily shut down to wait for the battery temperature to gradually recover, until the water pump is also temporarily shut down to assist in raising the battery temperature. b. When the overall temperature of the battery cell is judged to be too high, the water circuit controller adopts the cooling mode of upgrading the water circuit by one level, controls the proportional valve, three-way valve a and three-way valve b to adjust the water circuit connection status and switch it from series to mixed connection and then to parallel connection, and simultaneously increases the flow power of the speed-regulating water pump. If the overall temperature of the operation is still too high when it is increased to the parallel mode, the water cooler is controlled to adopt the high-efficiency cooling mode, the refrigeration compressor of the water cooler increases the operating speed to continue working, and the cooling fan of the water cooler increases the operating speed simultaneously. If the overall temperature of the operation is still too high, the speed-regulating water pump is controlled to further increase the speed to increase the water flow, and adopt intermittent peak speed power operation.

9. The control method of the electric vehicle battery cooling water circuit temperature reduction system according to claim 7, characterized in that: The temperature strategy is determined by the battery temperature difference range, including: c. When the local temperature is judged to be low based on the comprehensive judgment of the battery cell temperature, that is, the temperature of the input end of the water system is low, and the temperature increases in ascending order toward the output end, resulting in a large temperature difference, the water controller adjusts the two-position four-way reversing valve to reverse the water flow, turning the low-temperature input end into the output end, and using the step-by-step temperature rise between the compartments to raise the temperature of the original input end. d. When the local temperature is too high based on the comprehensive judgment of the battery cell temperature, that is, the temperature of the output end of the water system is too high, and the temperature is in descending order toward the input end, resulting in a large temperature difference, the water controller adjusts the two-position four-way reversing valve to reverse the water flow, so that the high-temperature output end becomes the input end, and the original output end temperature is effectively cooled by using the principle that the coolant temperature at the inflow end is lower and the cooling effect is better; e. The irregular temperature difference between the compartments is determined comprehensively based on the battery cell temperature. That is, when the temperature is locally low or high, the irregular temperature difference between the compartments occurs. The water circuit controller controls the proportional valve, three-way valve a and three-way valve b to adjust the water circuit connection status.

10. The control method of the electric vehicle battery cooling water circuit temperature reduction system according to claim 9, characterized in that: The local low or high temperature is the irregular temperature difference between the private rooms. The water circuit controller controls the proportional valve, three-way valve a and three-way valve b to adjust the water circuit connection status, including: When several battery packs with temperature deviations are placed completely in one or several branches in a parallel connection manner, and there are no packs in the normal temperature range in the branches that affect the independent cooling of the packs with large temperature differences, the parallel connection manner is adopted through program control, and the proportional valves of the water circuits of the packs with temperature differences within the normal range are program controlled, and the pipe opening of the proportional valve is reduced to limit the coolant flow, allowing more coolant to pass through the branches with higher temperatures for more sufficient cooling to form a difference in cooling effect to reversely adjust the temperature difference, and collect the opening feedback value of the proportional valve, and adjust the opening value according to the temperature cooling control effect until the system temperature difference is effectively controlled and restored to the normal temperature difference range; If several packages with temperature deviations cannot be completely placed in one or several branches through hybrid connection, and there are packages in the normal temperature range in the branch that affect the independent cooling of packages with large temperature differences, it is necessary to use program control in parallel to perform completely independent water cooling control on all packages, and program control adjustment on the water proportional valves of packages with temperature differences within the normal range, reduce the pipe opening of the proportional valve to limit the flow of coolant, and allow more coolant to pass through the branch with higher temperature to more fully cool the battery packs with high temperature and excessive temperature difference, so as to form a difference in cooling effect to reversely adjust the temperature difference, and collect the feedback value of the proportional valve opening, and adjust the opening value according to the temperature cooling control effect until the system temperature difference is effectively controlled and restored to the normal temperature difference range; When the irregular temperature difference between packs is eliminated, but there is an irregular temperature difference within the pack or some packs already have internal temperature differences, and the temperature difference within the pack conforms to the rule of low inlet temperature and high outlet temperature, the proportional valve can be used to limit the flow and concentrate the water flow to cool the battery packs with large temperature differences. At the same time, a programmable reversing valve can be used to change the water flow direction to reversely balance the internal temperature of some battery packs with large internal temperature differences.

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