Thermal management system and parameter control method for energy storage battery with air cooling and liquid cooling coupling

Abstract

The present invention discloses an energy storage battery thermal management system and parameter control method coupled with air cooling and liquid cooling, belonging to the technical field of battery thermal management; the system includes a battery pack, the battery pack is equipped with fins, a liquid cooling plate is arranged at the lower end of the battery pack, the liquid cooling plate is connected to a water pump and a heat exchanger, and an air conditioning unit and a compressor are arranged on one side of the heat exchanger; a battery housing is arranged at the upper end of the liquid cooling plate, a plurality of fans are arranged on one side of the battery pack housing, and an air intake grille is arranged on the other side of the battery pack housing. The fan can initially cool down the battery, and then the air cooling coupled with the liquid cooling system strengthens the heat dissipation; the PSA controller is used to optimize the speed of the fan, compressor and water pump in the coupling mode, and the PSA optimization algorithm is used to calculate the optimal fan output speed, compressor output speed and water pump output speed, thereby improving the heat dissipation efficiency while minimizing the energy consumption of the thermal management execution system, and providing an effective optimization means for the research and development and production of the actual battery thermal management system.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery thermal management, and in particular relates to an air-cooled and liquid-cooled coupled energy storage battery thermal management system and a parameter control method. Background Art

[0002] With the rapid development of power systems, the research and application of battery thermal management technology has received increasing attention. Batteries generate a lot of heat during operation. If the heat cannot be dissipated in a timely and effective manner, it will seriously affect the performance and life of the battery, and may even lead to safety accidents. Therefore, the development of an efficient and stable battery thermal management system is of great significance to improving battery performance and safety.

[0003] In the prior art, although air cooling and liquid cooling systems each have their own advantages, they both have obvious shortcomings. The air cooling system has a simple structure and low cost, but the heat dissipation effect is limited under high temperature or high load conditions; the liquid cooling system has high heat dissipation efficiency, but the system is complex, the cost is high, and there is a potential risk of liquid leakage. In addition, most of the existing battery thermal management systems lack intelligent control strategies and cannot be dynamically adjusted according to the actual working status of the battery, resulting in unstable heat dissipation effects, which may even affect the performance and life of the battery.

[0004] For example, the patent with application number CN202220696609.7 discloses a mobile energy storage battery thermal management device, in which the air conditioning system is used for heat dissipation and the phase change material is used for auxiliary heat dissipation, but the structure has a large space requirement; the patent with application number 202311343690.6 provides a cooling circuit design for the power battery and the motor or designs a battery cooling structure, but this technology optimizes the pipe connections of the existing equipment and improves the battery temperature control to a certain extent, but does not mention the battery energy consumption control; the patent with application number CN202410363315.6 is an efficient heat dissipation device for new energy vehicle batteries, which adopts liquid cooling and air cooling coupled heat dissipation, but the separate fan in the patent is installed at the bottom, which may increase the unevenness of the battery temperature. This cooling effect and performance have certain limitations. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an energy storage battery thermal management system coupled with air cooling and liquid cooling, namely a parameter control method, which solves the problems in the prior art.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] An energy storage battery thermal management system coupled with air cooling and liquid cooling includes a battery pack, a liquid cooling plate is arranged at the lower end of the battery pack, a plurality of parallel flow channels are arranged inside the liquid cooling plate, a water pump is connected to the flow channel inlet side of the liquid cooling plate through a water pipe, the water pump is connected to a heat exchanger through a water pipe, the heat exchanger is connected to the flow channel outlet of the liquid cooling plate through a water pipe, one side of the heat exchanger is connected to an air conditioning unit through a water pipe, and the air conditioning unit is connected to a compressor through a water pipe;

[0008] A battery housing is provided at the upper end of the liquid cooling plate to cover the battery pack. The battery housing is divided into chamber A, chamber B and chamber C by a partition to respectively accommodate the batteries in the battery pack. A plurality of air outlets are provided on one side of the battery housing, and a fan is installed at the air outlet. An air intake grille is provided on the other side of the battery housing.

[0009] The system also includes a PSA controller to detect the last battery cell temperature T in each chamber. ba or T bb or T bc , battery operating current I, coolant temperature T c and the air temperature T a As the input parameters, the PID search algorithm is used to optimize the output speed of the fan, the output speed of the compressor and the water pump.

[0010] Furthermore, the flow channel inlet of the liquid cooling plate is located at an upper portion of one side of the liquid cooling plate, and the flow channel outlet is located at a lower portion of another side of the liquid cooling plate.

[0011] Furthermore, a PTC heating module is provided on the water pipe between the heat exchanger and the flow channel outlet for preheating the battery pack, and the compressor and the PTC heating module do not work at the same time.

[0012] Furthermore, the air outlet is provided with an air outlet temperature sensor a, an air outlet temperature sensor b and an air outlet temperature sensor c, and the air intake grille is provided with an air inlet temperature sensor to respectively measure the air temperature at the air outlet and the air inlet of the battery housing; the flow channel outlet and the flow channel inlet of the liquid cooling plate are respectively provided with an outlet temperature sensor and an inlet temperature sensor to respectively measure the coolant temperature at the flow channel outlet and the flow channel inlet of the liquid cooling plate; the battery pack is provided with a battery temperature sensor a, a battery temperature sensor b and a battery temperature sensor c to measure the temperature T of the last battery ba , T bb and T bc .

[0013] Furthermore, in the thermal management system, the air cooling and liquid cooling startup strategies include:

[0014] The fan needs a battery temperature of T b >T1,T b T ba , Tbb and T bc the maximum value in, where T min < T b ≤ T1, T min the lower limit of the battery temperature, the fan runs at full speed, and the air-cooling start threshold is T1; when the battery temperature T b < T1, the fan is turned off;

[0015] The operation of the water pump and the compressor requires the battery temperature T b > T2, where T2 < T b ≤ T max , T max is the upper limit of the battery temperature, and at this time the PSA controller participates in the operation of the air-cooling system and the liquid-cooling system; when the battery temperature T b < T2, the water pump and the compressor are turned off.

[0016] In the thermal management system, the steps of the PID search algorithm include:

[0017] S1, set the number of decision variables, and set the upper and lower limits of the decision variables to H and L respectively, the maximum number of iterations T and the number size n;

[0018] S2, limit the search range of the variable X ij to: L j ~ H j ;

[0019] S3, calculate the objective function value and calculate the system deviation;

[0020] The objective function is:

[0021]

[0022] The objective function value f of the i-th individual i is:

[0023] f i = F(X ij )

[0024] The system deviation e of the number of iterations t k-1 (t) is:

[0025] e k-1 (t) = e k (t - 1) + x * (t) - x * (t - 1)

[0026] In the PSA algorithm, x * (t - 1) is the individual at the historical minimum value at the number of iterations t - 1; x(t) is the set value;

[0027] S4. Calculate the incremental PID output value Δu(t):

[0028] Δu(t) = K p ·r2·[e k (t) - e k-1 (t)] + K i ·r3·e k (t) + K d ·r4·[e k (t) - 2e k-1 (t) + e k-2 (t)]

[0029] where K p is the proportionality coefficient, K i is the integral coefficient, K d is the differential coefficient; r2, r3, and r4 are random numbers between 0 and 1; e k (t) is the process of approaching the solution;

[0030] S5. Calculate the condition factor o(t):

[0031]

[0032] where r5 is a random number between 0 and 1, λ is the adjustment coefficient, and L is the L'evy flight function;

[0033] S6. Update the population according to the incremental PID output value and the condition factor;

[0034] S7. Judge the termination condition. When the system operation conditions are met, output the rotational speeds of the fan, water pump, and compressor; otherwise, return to S3 for cycling.

[0035] Furthermore, in S7, the system operation termination conditions are: when the temperature T b of the last battery cell < T2, the water pump is turned off; when T min < T b < T1, the fan is turned off.

[0036] Furthermore, the update formula for updating the population in S6 is:

[0037] x(t + 1) = x(t) + η·Δu(t) + (1 - η)·o(t)

[0038] η = r6cos(t / T)

[0039] where r6 is an n - row and 1 - column matrix of random numbers between 0 and 1, and η is a coefficient matrix.

[0040] The parameter control method of the above - mentioned air - cooled and liquid - cooled coupled energy storage battery thermal management system includes the following steps:

[0041] S1, set the number of decision variables, and the upper and lower limits of the decision variables are set to H and L respectively, the maximum number of iterations T and the number size n;

[0042] S2, limited variable X ij Search range: L j ~H j ;

[0043] S3, find the objective function value and calculate the system deviation;

[0044] The objective function is:

[0045]

[0046] The objective function value f of the i-th individual i for:

[0047] f i =F(X ij )

[0048] System deviation e at iteration number t k (t) is:

[0049] e k (t) = x * (t-1)-x(t-1)

[0050] Among them, x * (t) is the individual with the historical minimum at iteration number t; x(t) is the set value;

[0051] S4, calculate the incremental PID output value Δu(t):

[0052] Δu(t)=K p ·r2·[e k (t)-e k-1 (t)]+K i ·r3·e k (t)+k d ·r4·[e k (t)-2e k-1 (t)+e k-2 (t)]

[0053] Among them, K p is the proportionality coefficient, K i is the integration coefficient, K d is the differential coefficient; r2, r3 and r4 are random numbers between 0 and 1; e k (t) is the process of approaching the solution;

[0054] S5, calculate the condition factor o(t):

[0055]

[0056] Among them, r5 is a random number from 0 to 1, λ is an adjustment coefficient, and L is the L'evy flight function;

[0057] S6. Update the population according to the incremental PID output value and the condition factor. The update formula is:

[0058] x(t + 1) = x(t) + η·Δu(t) + (1 - η)·o(t)

[0059] η = r6cos(t / T)

[0060] In the formula, r6 is an n-row and 1-column matrix of random numbers from 0 to 1, and η is a coefficient matrix;

[0061] S7. Judge the termination condition. When the system operation conditions are met, output the fan speed, water pump speed, and compressor speed; otherwise, return to S3 for cycling.

[0062] The system operation termination condition in S7 is: when the temperature T of the last battery cell b < T2, the water pump is closed; when T min < T b < T1, the fan is closed.

[0063] Advantages of the present invention:

[0064] The present invention can flexibly adjust the heat dissipation method according to the working state of the battery and the external environmental conditions. According to the battery temperature, coolant temperature, ambient temperature, and battery current, the required fan speed and water pump speed are calculated through the PSA algorithm, so as to maximize the heat dissipation efficiency. At the same time, fins are installed on the battery, which strengthens the air disturbance and enhances the heat dissipation effect, providing a convenient and effective optimization means for the research and development and production of the actual battery thermal management system. Description of the Drawings

[0065] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0066] Figure 1 is the general assembly drawing of the thermal management system of the present invention;

[0067] Figure 2 is the schematic diagram of the battery housing and the air intake grille of the present invention;

[0068] Figure 3 is the assembly drawing of the battery and the liquid cooling plate of the present invention;

[0069] Figure 4 This is a diagram of the internal flow path of the liquid cooling plate of the present invention;

[0070] Figure 5 is a chamber distribution diagram of the present invention;

[0071] Figure 6 It is a flow chart of the implementation of the PID search algorithm of the present invention;

[0072] Figure 7 is a schematic diagram of the thermal management control scheme of the present invention;

[0073] Figure 8 is the PSA of the present invention k-1 (t) is the updated trajectory.

[0074] In the figure: 1-air conditioning unit, 2-water pump, 3-battery housing, 4-fan, 5-heating module, 6-heat exchanger, 7-air outlet temperature sensor a, 8-battery pack, 9-liquid cooling plate, 10-battery temperature sensor a, 11-air intake grille, 12-air inlet temperature sensor, 13-outlet temperature sensor, 14-inlet second temperature sensor, 15-compressor, 16-PSA controller, 17-air outlet temperature sensor b, 18-air outlet temperature sensor c, 19-battery temperature sensor b, 20-battery temperature sensor c, 21-fin, 22-partition, 23-A chamber, 24-B chamber, 25-C chamber. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] Example 1

[0077] like Figures 1 to 5 As shown, the thermal management system of the energy storage battery coupled with air cooling and liquid cooling comprises: a battery pack 8 composed of a plurality of battery cells, a fin 21 is installed on the surface of the battery pack 8 to improve the heat dissipation effect, a liquid cooling plate 9 is arranged at the lower end, a plurality of parallel flow channels are arranged inside the liquid cooling plate 9, and a coolant is passed into the flow channels to realize liquid cooling of the battery pack 8;

[0078] A battery housing 3 is provided at the upper end of the liquid cooling plate 9, and can cover the battery pack 8. The battery housing 3 is divided into chamber A 23, chamber B 24 and chamber C 25 by a partition 22. The battery pack 8 is installed in chamber A 23, chamber B 24 and chamber C 25. A plurality of air outlets are provided on one side of the battery housing 3, and corresponding fans 4 are installed at the air outlets. An air intake grille 11 is provided on the other side of the battery housing 3. The fan 4 is operated to exhaust air, which can generate airflow through the air intake grille 11 to cool the battery pack 8.

[0079] In this embodiment, if Figure 4 As shown, the flow channel inlet of the liquid cooling plate 9 is located at the upper part of one side of the liquid cooling plate 9, and the flow channel outlet is located at the lower part of the other side of the liquid cooling plate 9, so as to ensure that the liquid cooling plate 9 can be filled with liquid;

[0080] The flow channel inlet side of the liquid cooling plate 9 is connected to a water pump 2 through a water pipe, the water pump 2 is connected to a heat exchanger 6 through a water pipe, the heat exchanger 6 is connected to the flow channel outlet of the liquid cooling plate 9 through the water pipe, an air conditioning unit 1 is arranged on one side of the heat exchanger 6, the air conditioning unit 1 is connected to a compressor 15, the compressor 15 is connected to the heat exchanger 6 through a water pipe, and a refrigeration cycle is formed; under the action of the water pump 2, the liquid enters the liquid cooling plate 9 from the flow channel inlet and flows out of the liquid cooling plate 9 from the flow channel outlet, and under the action of the air conditioning unit 1 and the heat exchanger 6, the liquid flowing out of the flow channel outlet is cooled and then recycled;

[0081] The PSA controller 16 is connected to the fan 4, the water pump 2 and the compressor 15 respectively; the PSA controller 16 is used to optimize the rotation speeds of the fan, the compressor and the water pump, and uses the temperature of the last battery cell in each chamber, the battery operating current, the temperature of the coolant and the air temperature as input parameters, and uses the PSA optimization algorithm to calculate the optimal output rotation speed of the fan, the output rotation speed of the compressor and the output rotation speed of the water pump, thereby improving the heat dissipation efficiency while minimizing the energy consumption of the thermal management execution system, and providing a convenient and effective optimization means for the research and development and production of the actual battery thermal management system;

[0082] In addition, a PTC heating module 5 is provided on the water pipe connecting the heat exchanger 6 and the flow channel outlet. The PTC heating module 5 is used for preheating the battery pack 8 when the temperature is low. The compressor 27 and the PTC heating module 5 do not work at the same time.

[0083] The air outlet is provided with an air outlet temperature sensor a 7, an air outlet temperature sensor b 17, and an air outlet temperature sensor c 18, and the air inlet temperature sensor 12 is provided on the air inlet grille 11 to measure the temperatures of the air outlet and the air inlet of the battery housing 3 respectively;

[0084] An outlet temperature sensor 13 and an inlet temperature sensor 14 are respectively arranged at the flow channel outlet and the flow channel inlet of the liquid cooling plate 9 to measure the coolant temperature at the flow channel outlet and the flow channel inlet of the liquid cooling plate 9;

[0085] A battery temperature sensor a 10, a battery temperature sensor b 19 and a battery temperature sensor c 20 are arranged on the battery pack 8 to measure the temperature T in the last battery of the three chambers ba 、T bb and T bc 。

[0086] Embodiment 2

[0087] As Figure 7 shown, in the battery thermal management system, the battery temperature T b (T ba 、T bb and T bc the maximum value among), the battery working current I, the temperature T c of the coolant, and the air temperature T a are used as the inputs of the PID search algorithm (PSA), so as to obtain the output speeds of the fan 4, the compressor 15 and the water pump 2, and control the operation of the fan, the compressor and the water pump; The PID search algorithm limits the variable range on the basis of the traditional PID, sets the target value as the optimal solution after each iteration, and obtains the best parameters through iterative optimization and applies them to the system;

[0088] In this embodiment, the highest temperature T b in the last three batteries of the battery packs 8 in the A chamber 23, the B chamber 24 and the C chamber 25 is obtained, and the highest temperature T bmax of the single battery, the lowest temperature T bmin of the single battery, the battery working current I, the coolant temperature T c and the air temperature T a in the battery packs 8 in the A chamber 23, the B chamber 24 and the C chamber 25 are obtained;

[0089] The fan 4 needs to operate when the battery temperature T b > T1, T b is the maximum value of T ba 、T bb and T bc , where T min < T b ≤ T1, T min the lower limit of the battery temperature, the fan runs at full speed, and the air-cooled start threshold is T1; When the battery temperature T b < T1, the fan 4 is turned off;

[0090] The water pump 2 and the compressor 15 need to operate when the battery temperature Tb >T2, where T2 < T b ≤T max , T max is the upper limit of the battery temperature. At this time, the PSA controller 16 participates in the operation of the air cooling system and the liquid cooling system; when the battery temperature T b < T2, the water pump 2 and the compressor 15 are turned off. Among them, there is a requirement for the uniformity of the battery pack temperature: ΔT ≤ q; when the highest battery temperature drops to the operation threshold of the water pump 2 and the compressor 15, the liquid cooling operation stops; when the highest battery temperature in the chamber drops to the fan operation threshold, the fan 4 corresponding to the chamber stops running;

[0091] In this embodiment, the heat dissipation of the battery mainly relies on thermal management, and the performance of thermal management mainly depends on the regulation of the rotation speeds of the fan 4, the compressor 15, and the water pump 2.

[0092] The optimization problem consists of a set of decision variables, constraints, and an objective function;

[0093] The heat dissipation of air cooling changes with the air temperature T a and the fan rotation speed n f The heat dissipation of the fan can be expressed as:

[0094] Q f = c a m a ΔT1 = c a Kn f ΔT1

[0095] Among them, Q f is the heat dissipation of air cooling; c a is the specific heat capacity of air; m a is the mass flow rate of air; K is a proportionality coefficient; m a and n f are linearly related by default, that is, m a = Kn f ; ΔT1 is the change in air temperature, which is obtained by measuring the temperature difference between the two using the inlet air temperature sensor 12 and the outlet air temperature sensors a7, b17, and c18 respectively.

[0096] The heat dissipation of liquid cooling changes with the coolant temperature T c and the water pump rotation speed n p The heat dissipation of the coolant can be expressed as:

[0097] Q c = c c m c ΔT2 = c c (V p ηn pρ / 60)ΔT2

[0098] Where Q c is the heat dissipation of liquid cooling; c c is the specific heat capacity of the coolant; m c is the mass of coolant flowing through the battery; m c With n p The relationship is expressed as m c =V p ηn p ρ / 60, where V p is the water pump displacement, η is the volumetric efficiency of the water pump, and ρ is the density of the coolant; ΔT2 is the temperature change of the coolant, which is obtained by measuring the difference between the coolant outlet temperature and the inlet temperature by the outlet temperature sensor 13 and the inlet temperature sensor 14.

[0099] Battery temperature change It can be expressed as:

[0100]

[0101] Among them, c b and m b are the specific heat capacity and mass of the battery, I is the operating current of the battery, R is the internal resistance of the battery, is the battery heat generation rate, is the total heat dissipation,

[0102] Coolant temperature T c , air temperature and battery operating current I are used as the input of the system, and the output is the mass flow rate of air and coolant. Due to the different capacities and efficiencies of different fans and water pumps, there will be different relationships between mass flow rate and speed.

[0103] This data can be used as the optimization objective function of the thermal management system:

[0104]

[0105] The constraints are:

[0106] T min ≤T b ≤T max

[0107] ΔT≤q

[0108] Where K1, K2, K3 and K4 are weight coefficients, P f is the power consumption of the fan; P pump is the power consumption of pump 2, P com is the power consumption of the compressor, T ris the set target temperature; ΔT is the maximum temperature difference of the batteries in the battery pack 8.

[0109] like Figure 6 and Figure 7 As shown, the steps of using the PID search algorithm (PSA) to calculate the output speed of the fan 4, the compressor 15 and the output speed of the water pump 2 include:

[0110] S1, initialization parameters;

[0111] Decision variables of thermal management system: the temperature T of the last battery in the battery pack in the chamber b , T b It is T ba , T bb , T bc The maximum value, the battery operating current I, the coolant temperature T c and air temperature T a , set the number of decision variables to m, and set the upper and lower limits of the decision variables to H and L respectively; the control parameters of PSA include the maximum number of iterations T and the number size n;

[0112] S2, creating groups;

[0113] In order to limit the search range, the initial population variable X ij It can be expressed as:

[0114] x ij =(H j -L j )·r1+L j ,i=1,2,…,n; j=1,2,…,m,

[0115] Among them, r1 is a random number between 0 and 1, i is the i-th variable, j is the j-th dimension of the variable, and H j is the upper limit of the j-th dimension, L j is the lower limit of the jth dimension; so X ij The search range is: L j ~H j ;

[0116] S3, find the objective function value and calculate the system deviation;

[0117] The objective function is:

[0118]

[0119] The objective function value f of the i-th individual i From the equation f i =F(X ij )calculate;

[0120] The systematic deviation e of the regular number of iterations t k (t) is:

[0121] e k (t) = x * (t-1)-x(t-1)

[0122] In the PSA algorithm, x * (t) is the individual with the historical minimum value at iteration number t; x(t) is the set value. When t = 1, e k-2 (t) = e k-1 (t) = e k (t); when t>1, e k-2 (t) = e k-1 (t);

[0123] e k-2 (t),e k-1 (t),e k (t) represents the deviation of the first two iterations, the deviation of the previous iteration, and the deviation of the current iteration, respectively;

[0124] Since the set value in the PSA algorithm is the optimal value, but the optimal value after each iteration is changing, in order to reduce the complexity of the algorithm, the system deviation in PSA It can be expressed as e k-1 (t) = e k (t-1)+x * (t)-x * (t-1), such as Figure 8 The e shown k (t) is shown in the trajectory diagram;

[0125] S4, calculate the incremental PID output value;

[0126] PSA uses incremental PID for regulation, and its output is calculated based on the difference between the control error at the current moment and the control error at the previous moment, rather than directly based on the control error at the current moment; the incremental type is:

[0127] Δu(t)=K p ·r2·[e k (t)-e k-1 (t)]+K i ·r3·e k (t)+K d ·r4·[e k (t)-2e k-1 (t)+e k-2 (t)]

[0128] Among them, Δu(t) is the incremental PID output value, K pis the proportionality coefficient, K i is the integration coefficient, K d is the differential coefficient; r2, r3 and r4 are random numbers between 0 and 1, which are used to increase the search area; e k (t) is the process of approaching the solution, e k (t)-2e k-1 (t)+e k-2 (t) and e k (t)-e k-1 The role of (t) is to produce fluctuations that make the population more diverse;

[0129] The proportional, integral and differential factors are adjusted according to different situations and problems. The specific steps for adjusting the proportional factor, integral factor and differential factor are as follows:

[0130] Proportional factor: controls the fluctuations in the process of approaching the solution, K p The larger the setting, the greater the fluctuation and the larger the search range;

[0131] Integral factor: controls the strength of the output solution, K i The larger the setting, the stronger the output result;

[0132] Differential factor: the degree of change of control deviation, K d The larger the setting, the greater the deviation;

[0133] The proportional factor, integral factor and differential factor are adjusted respectively so that the solution process can fully search within a certain range, thus making the objective function tend to be optimal.

[0134] S5, calculation of conditional factors;

[0135] Over time, if the controlled object is not adjusted, its true value may quickly deviate from the set value. To prevent this from happening, a constant is usually added to the original adjustment value. Therefore, a conditional factor called zero output is added to the original Δu(t) to prevent the algorithm from falling into a local optimum; zero output is defined in the equation:

[0136]

[0137] Where o(t) is the conditioning factor, given the initial adjustment value of the system, r5 is a random number between 0 and 1, λ is the adjustment coefficient, and L is the L'evy flight function:

[0138]

[0139] Where u and v are matrices of n-row and d-column random numbers that follow a standard normal distribution, respectively; β is a factor set to ω.

[0140] S6, update group;

[0141] The update of all individuals is related to Δu(t) and o(t); the update formula is expressed as:

[0142] x(t + 1) = x(t) + η·Δu(t) + (1 - η)·o(t)

[0143] η = r6cos(t / T)

[0144] Wherein, r6 is a matrix of random numbers from 0 to 1 in an n-row and 1-column, and η is a coefficient matrix.

[0145] S7. Judge the termination condition; when the system termination condition is satisfied, the fan, water pump and compressor terminate operation, otherwise return to step 3 for circulation;

[0146] The system termination condition is: when the battery temperature T b < T2, the water pump is closed and the compressor is closed; when T min < T b < T1, the fan is closed.

[0147] Apply this control strategy to the battery temperature of different chambers, adopt air cooling for preliminary heat dissipation, and then couple liquid cooling to strengthen heat dissipation to ensure the uniformity of the battery.

[0148] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0149] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. The thermal management system of energy storage battery with air cooling and liquid cooling coupling is characterized in that: The invention comprises a battery pack (8), a liquid cooling plate (9) is arranged at the lower end of the battery pack (8), a plurality of parallel flow channels are arranged inside the liquid cooling plate (9), a water pump (2) is connected to the flow channel inlet side of the liquid cooling plate (9) through a water pipe, the water pump (2) is connected to the heat exchanger (6) through the water pipe, the heat exchanger (6) is connected to the flow channel outlet of the liquid cooling plate (9) through the water pipe, one side of the heat exchanger (6) is connected to the air conditioning unit (1) through the water pipe, and the air conditioning unit (1) is connected to the compressor (15) through the water pipe; A battery housing (3) is provided at the upper end of the liquid cooling plate (9) to cover the battery pack (8); the battery housing (3) is divided into chamber A (23), chamber B (24) and chamber C (25) by a partition (22) to respectively accommodate the batteries in the battery pack (8); a plurality of air outlets are provided on one side of the battery housing (3), and a fan (4) is installed at the air outlet; an air intake grille (11) is provided on the other side of the battery housing (3); The system also includes a PSA controller (16) that uses the last battery cell temperature T in each chamber to b , battery operating current I, coolant temperature T c and the air temperature T a As input parameters, a PID search algorithm is used to optimize the output speed of the fan (4), the output speed of the compressor (15) and the output speed of the water pump (2); In the thermal management system, the steps of the PID search algorithm include: S1, set the number of decision variables, and the upper and lower limits of the decision variables are set to H and L respectively, the maximum number of iterations T and the number size n; S2, limit variable X ij Search range: L j ~H j ; S3, find the objective function value and calculate the system deviation; The objective function is: The constraints are: T min ≤T b ≤T max , ΔT≤q; Among them, K1, K2, K3 and K4 are weight coefficients, P f is the power consumption of the fan; P pump is the power consumption of the pump (2), P com is the power consumption of the compressor, T r is the set target temperature; ΔT is the maximum temperature difference of the batteries in the battery pack (8); T min is the lower limit of battery temperature, T max is the upper limit of battery temperature; The objective function value f of the i-th individual i for: f i =F(X ij ) System deviation e at iteration number t k-1 (t) is: e k-1 (t)=e k (t-1)+x * (t)-x * (t-1) In the PSA algorithm, x * (t-1) is the individual with the historical minimum value at iteration t-1; x(t) is the set value; S4, calculate the incremental PID output value Δu(t): Δu(t)=K p ·r2·[e k (t)-e k-1 (t)]+K i ·r3·e k (t)+K d ·r4·[e k (t)-2e k-1 (t)+e k-2 (t)] Among them, K p is the proportionality coefficient, K i is the integration coefficient, K d is the differential coefficient; r2, r3 and r4 are random numbers between 0 and 1; e k (t) is the process of approaching the solution; S5, calculate the condition factor o(t): Among them, r5 is a random number between 0 and 1, λ is the adjustment coefficient, and L is the L'evy flight function; S6, updating the group according to the incremental PID output value and the condition factor; S7, judging the termination conditions, if the system operation conditions are met, outputting the rotation speed of the fan (4), the rotation speed of the water pump (2) and the rotation speed of the compressor (15), otherwise returning to S3 loop.

2. The air-cooled and liquid-cooled coupled energy storage battery thermal management system according to claim 1 is characterized in that: The flow channel inlet of the liquid cooling plate (9) is located at the upper part of one side of the liquid cooling plate (9), and the flow channel outlet is located at the lower part of the other side of the liquid cooling plate (9).

3. The air-cooled and liquid-cooled coupled energy storage battery thermal management system according to claim 2 is characterized in that: A PTC heating module (5) is provided on the water pipe between the heat exchanger (6) and the flow channel outlet for preheating the battery pack (8); the compressor (15) and the PTC heating module (5) do not work at the same time.

4. The air-cooled and liquid-cooled coupled energy storage battery thermal management system according to claim 3 is characterized in that: The air outlet is provided with an air outlet temperature sensor a (7), an air outlet temperature sensor b (17) and an air outlet temperature sensor c (18), and the air inlet grille (11) is provided with an air inlet temperature sensor (12) to respectively measure the air temperature at the air outlet and air inlet of the battery housing (3); the flow channel outlet and flow channel inlet of the liquid cooling plate (9) are provided with an outlet temperature sensor (13) and an inlet temperature sensor (14) to respectively measure the coolant temperature at the flow channel outlet and flow channel inlet of the liquid cooling plate (9); the battery pack (8) is provided with a battery temperature sensor a (10), a battery temperature sensor b (19) and a battery temperature sensor c (20) to measure the temperature T of the last battery ba , T bb and T bc .

5. The air-cooled and liquid-cooled coupled energy storage battery thermal management system according to claim 4 is characterized in that: In the thermal management system, the air cooling and liquid cooling startup strategies include: The fan (4) needs the battery temperature T to run b > T1, T b is T ba , T bb and T bc is the maximum value among them, where T min < T b ≤ T1, T min is the lower limit of the battery temperature, the fan runs at full speed, and the air-cooling start threshold is T1; when the battery temperature T b < T1, the fan (4) is turned off; The operation of the water pump (2) and the compressor (15) requires the battery temperature T b > T2, where T2 < T b ≤ T max , T max is the upper limit of the battery temperature. At this time, the PSA controller (16) participates in the operation of the air-cooling system and the liquid-cooling system; when the battery temperature T b < T2, the water pump (2) and the compressor (15) are turned off.

6. The air-cooled and liquid-cooled coupled energy storage battery thermal management system according to claim 5, characterized in that: In S7, the system operation termination conditions are as follows: when the temperature T of the last battery b < T2, the water pump is turned off; when T min < T b < T1, the fan is turned off.

7. The air-cooled and liquid-cooled coupled energy storage battery thermal management system according to claim 6, characterized in that: The update formula for updating the population in S6 is: x(t+1)=x(t)+η·Δu(t)+(1-η)·o(t) η=r6cos(t / T) Where r6 is a matrix of n rows and 1 column containing random numbers from 0 to 1, and η is a coefficient matrix.

8. The parameter control method of the energy storage battery thermal management system coupled with air cooling and liquid cooling according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1, set the number of decision variables, and the upper and lower limits of the decision variables are set to H and L respectively, the maximum number of iterations T and the number size n; S2, limit variable X ij Search range: L j ~H j ; S3, find the objective function value and calculate the system deviation; The objective function is: The objective function value f of the i-th individual i for: f i =F(X ij ) System deviation e at iteration number t k (t) is: e k (t)=x * (t-1)-x(t-1) Among them, x * (t) is the individual with the historical minimum at iteration number t; x(t) is the set value; S4, calculate the incremental PID output value Δu(t): Δu(t)=K p ·r2·[e k (t)-e k-1 (t)]+K i ·r3·e k (t)+K d ·r4·[e k (t)-2e k-1 (t)+e k-2 (t)] Among them, K p is the proportionality coefficient, K i is the integration coefficient, K d is the differential coefficient; r2, r3 and r4 are random numbers between 0 and 1; e k (t) is the process of approaching the solution; S5, calculate the condition factor o(t): Among them, r5 is a random number between 0 and 1, λ is the adjustment coefficient, and L is the L'evy flight function; S6, updates the group according to the incremental PID output value and the condition factor, and the update formula is: x(t+1)=x(t)+η·Δu(t)+(1-η)·o(t) η=r6cos(t / T) Where r6 is a matrix of n rows and 1 column of random numbers from 0 to 1, and η is a coefficient matrix; S7, determine the termination conditions. If the system operating conditions are met, output the fan speed, water pump speed and compressor speed. Otherwise, return to S3 loop.

9. The parameter control method of the air-cooled and liquid-cooled coupled energy storage battery thermal management system according to claim 8, characterized in that: The system operation termination condition in S7 is: when the temperature T of the last battery b < T2, the water pump is turned off; when T min < T b < T1, the fan is turned off.

Images