Multi-type single battery composite battery control method, system and storage medium

Abstract

The application relates to the technical field of energy storage batteries, and discloses a composite battery control method and system of multiple types of single batteries and a storage medium. The method is based on a first lithium battery single body, a second lithium battery single body and a first nickel-hydrogen battery single body, acquires single body voltages and calculates a lithium battery voltage sum; during charging, the two lithium batteries are first connected in series for charging, if the voltage sum is greater than a preset charging voltage value, any lithium battery is connected in series with the nickel-hydrogen battery for charging; during discharging, the two lithium batteries are first connected in series for discharging, if the voltage sum is less than a preset discharging voltage value, any lithium battery is connected in series with the nickel-hydrogen battery for discharging. The method flexibly combines different types of single batteries in series, widens the voltage adaptation range of the battery pack, improves the charging and discharging stability and flexibility, reduces the dependence on high-priced hardware, and lowers the overall cost.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of energy storage batteries, in particular to a composite battery control method for multiple types of single batteries, a system and a storage medium. BACKGROUND

[0002] The fire of an energy storage lithium battery is caused by the coupling of the internal electrochemical reaction and the structural characteristics. The positive electrode material of the battery is easy to release oxygen under abnormal working conditions such as overcharging and short circuit, and has a violent reaction with the lithium metal extracted from the negative electrode, releasing a large amount of heat; at the same time, the electrolyte is mainly a flammable solvent of carbonic acid ester, which rapidly vaporizes and decomposes to produce combustible gas after being heated, and when the internal temperature of the battery exceeds the critical value of the boiling point of the electrolyte, the gas pressure rises rapidly, causing the shell to break, and the combustible gas mixes with air and ignites at high temperature or electric spark, causing a fire or even an explosion, and the chain reaction quickly spreads to the battery pack, expanding the scale of the accident.

[0003] Current temperature control and fire prevention measures for energy storage lithium batteries mainly include active prevention and passive protection. In terms of active prevention, the battery management system is used to monitor the voltage and temperature of the single battery in real time, overcharging is avoided through equalization charging, and a forced air cooling, liquid cooling or direct cooling system is used to start cooling when the temperature exceeds the threshold; passive protection relies on the flame-retardant material of the battery shell and the fireproof and heat-insulating pad between the battery cells.

[0004] In the active temperature control system, the heat exchanger, circulating pump and other components of the liquid cooling / direct cooling system have a cost that is 30%-50% higher than that of the forced air cooling system, and temperature sensors and control modules need to be additionally configured, and the high-precision chip for the BMS equalization function has a unit price that is 2-3 times that of the ordinary chip; the flame-retardant material and the fireproof and heat-insulating pad have a material cost that is more than 40% higher than that of the conventional material, and the installation and regular replacement of the fire extinguishing device cost 8%-12% of the total cost of the energy storage system on average per year. The existing temperature control and fire prevention measures have a significant cost problem. SUMMARY

[0005] In order to reduce the cost of battery safety measures, the application provides a composite battery control method for multiple types of single batteries, a system and a storage medium.

[0006] In the first aspect, the application provides a composite battery control method for multiple types of single batteries, which adopts the following technical scheme:

[0007] A composite battery control method for multiple types of single batteries, comprising the following steps:

[0008] Based on the set first lithium battery single cell, second lithium battery single cell and first nickel-hydrogen battery single cell;

[0009] Obtain the first voltage of the first lithium battery single cell, the second voltage of the second lithium battery single cell and the third voltage of the first nickel-hydrogen battery single cell;

[0010] The sum of the first voltage and the second voltage is a lithium battery voltage sum;

[0011] Based on the obtained charging instruction, the first lithium battery monomer and the second lithium battery monomer are connected in series and then charged; if the lithium battery voltage sum is greater than a preset charging voltage value, the first lithium battery monomer or the second lithium battery monomer is connected in series with the first nickel-hydrogen battery monomer and then charged.

[0012] Based on the obtained discharging instruction, the first lithium battery monomer and the second lithium battery monomer are connected in series and then discharged; if the lithium battery voltage sum is less than a preset discharging voltage value, the first lithium battery monomer or the second lithium battery monomer is connected in series with the first nickel-hydrogen battery monomer and then discharged.

[0013] By adopting the above technical solution, different types of monomer batteries (lithium batteries and nickel-hydrogen batteries) are flexibly connected in series and controlled. In the charging or discharging process, the series structure is dynamically adjusted according to the comparison result of the voltage sum of the lithium battery monomer and the preset voltage value. The lithium battery can be used for efficient charging and discharging when the voltage meets the requirements, and the nickel-hydrogen battery can be used for supplementary adjustment when the voltage is insufficient or too high. Thus, the collaborative work of multiple types of monomer batteries is realized, the voltage adaptation range of the battery pack is effectively widened, the charging and discharging stability and flexibility of the battery system under different working conditions are improved, and the overall cost is reduced without relying on high-precision chips or complex temperature control hardware.

[0014] Optionally, the first lithium battery monomer, the second lithium battery monomer, and the first nickel-hydrogen battery monomer are connected in series, and the first nickel-hydrogen battery monomer is located between the first lithium battery monomer and the second lithium battery monomer.

[0015] By adopting the above technical solution, the intermediate layout allows the nickel-hydrogen battery to participate in voltage adjustment more evenly during the charging and discharging process, avoids exacerbating the loss of a lithium battery monomer due to excessive voltage bearing, and is beneficial to balancing the work load of each monomer battery and prolonging the service life of the overall battery pack.

[0016] Optionally, the method further comprises:

[0017] In a set first period, the total capacity of the capacity of the first lithium battery monomer and the capacity of the second lithium battery monomer is calculated to obtain a lithium battery capacity.

[0018] The discharging voltage value is inversely related to the lithium battery capacity. The greater the lithium battery capacity, the smaller the discharging voltage value. The smaller the lithium battery capacity, the greater the discharging voltage value.

[0019] By adopting the technical scheme, when the lithium battery capacity is large, the discharge voltage value is reduced, when the capacity is small, the discharge voltage value is increased, the actual capacity state of the battery can be dynamically adapted, unnecessary loss caused by excessively high discharge voltage can be avoided when the capacity is sufficient, and the discharge efficiency and stability can be ensured by increasing the discharge voltage when the capacity is insufficient.

[0020] Optionally, the method further comprises:

[0021] The capacity of the first nickel-hydrogen battery cell is calculated as the nickel-hydrogen battery capacity according to a set second period;

[0022] The preset charging voltage value is inversely related to the nickel-hydrogen battery capacity; the larger the nickel-hydrogen battery capacity, the smaller the preset charging voltage value; the smaller the nickel-hydrogen battery capacity, the greater the preset charging voltage value;

[0023] Alternatively, the number of nickel-hydrogen batteries connected in parallel with the first nickel-hydrogen battery cell is positively related to the nickel-hydrogen battery capacity; the smaller the nickel-hydrogen battery capacity, the greater the number of nickel-hydrogen batteries connected in parallel; the greater the nickel-hydrogen battery capacity, the smaller the number of nickel-hydrogen batteries connected in parallel.

[0024] By adopting the technical scheme, when the nickel-hydrogen battery capacity is large, the charging voltage is reduced and the number of parallel connections is reduced, when the capacity is small, the charging voltage is increased or the number of parallel connections is increased, which can not only avoid overcharging risk or reduce unnecessary energy loss when the capacity is sufficient, but also ensure charging efficiency and power supply capacity by increasing the voltage or the number of parallel connections when the capacity is insufficient.

[0025] Optionally, the method further comprises:

[0026] The energy use speed and use temperature of the first lithium battery cell and the second lithium battery cell are obtained;

[0027] A working condition evaluation value is calculated according to the energy use speed and use temperature, and the working condition evaluation value = ω1×(vt / v_max) + ω2×(Tt / T_max); wherein vt is the current energy use speed, v_max is the preset maximum energy use speed; Tt is the current use temperature, T_max is the preset maximum allowable use temperature; ω1 and ω2 are weight coefficients of the energy use speed and use temperature respectively, and ω1 + ω2 = 1; (vt / v_max) and (Tt / T_max) are normalization processing items, and the value range is 0~1;

[0028] The first period is inversely related to the working condition evaluation value; the greater the working condition evaluation value, the shorter the corresponding first period; the smaller the working condition evaluation value, the longer the corresponding first period.

[0029] By adopting the technical scheme, the period is shortened when the working condition is harsh (the evaluation value is large) to monitor and adjust the lithium battery state more frequently, and the period is prolonged when the working condition is gentle (the evaluation value is small) to reduce unnecessary calculation and adjustment, so that the battery abnormality can be found and responded to in time through high-frequency monitoring under harsh working conditions, the system safety and stability are ensured, and unnecessary energy consumption and calculation load are reduced under gentle working conditions.

[0030] Optionally, the starting use voltage values of the plurality of first nickel-hydrogen battery cells after ending charging are recorded;

[0031] The ending use voltage values of the plurality of first nickel-hydrogen battery cells starting charging are recorded;

[0032] The comprehensive high voltage value is calculated according to the plurality of starting use voltage values;

[0033] The comprehensive low voltage value is calculated according to the plurality of ending use voltage values;

[0034] The use depth range is combined according to the comprehensive high voltage value and the comprehensive low voltage value;

[0035] The range coincidence degree value of the use depth range and the preset standard use range is calculated;

[0036] The second period is adjusted according to the range coincidence degree value, the higher the range coincidence degree value, the longer the second period, and the lower the range coincidence degree value, the shorter the second period.

[0037] By adopting the technical scheme, the period is prolonged when the coincidence degree is high to reduce unnecessary monitoring, and the period is shortened when the coincidence degree is low to strengthen monitoring, so that the system running load and energy consumption are reduced when the battery use state is stable, and the abnormality can be found in time through high-frequency monitoring and adjusted when the use state deviates from the standard, and dynamic adaptation of the nickel-hydrogen battery state monitoring is realized.

[0038] Optionally, the capacity of the first lithium battery cell is detected as a first capacity, and the capacity of the second lithium battery cell is detected as a second capacity;

[0039] The capacity difference value is calculated according to the first capacity and the second capacity;

[0040] The capacity unevenness is calculated according to the capacity difference value and a preset reference difference value;

[0041] If the capacity unevenness is less than a preset reference unevenness, the discharge voltage value is inversely relatedly adjusted according to the capacity unevenness; otherwise, the first nickel-hydrogen battery cell is cut out of the loop, and the first lithium battery cell and the second lithium battery cell are subjected to battery equalization repair.

[0042] By adopting the above technical solutions, the discharge voltage value is adjusted inversely when the unevenness is low to balance the performance, and the nickel-hydrogen battery is cut off and repaired when the unevenness exceeds the limit, so that the system can be maintained in stable operation through voltage adjustment when the capacity difference is slight to avoid the accumulation of small differences, and the repair mechanism can be started in time when the difference is significant to prevent the service life of the battery monomer from being attenuated or the safety risk due to long-term uneven work.

[0043] Optionally, the first nickel-hydrogen battery monomer adopts a liquid electrolyte structure filled with 5% penetrant, and the composite battery further comprises heat-conducting liquid for enhancing the heat conduction between the battery monomers and an explosion-proof hole arranged on the battery shell and capable of releasing pressure when the internal pressure exceeds the limit.

[0044] By adopting the above technical solutions, the ion conduction efficiency of the electrolyte can be improved by adopting the liquid electrolyte structure containing 5% penetrant for the first nickel-hydrogen battery monomer, the charge and discharge performance and response speed of the nickel-hydrogen battery are enhanced, and the cooperative working effect of the nickel-hydrogen battery and the lithium battery is optimized. Meanwhile, the heat-conducting liquid can enhance the heat conduction between the battery monomers and accelerate the heat diffusion to avoid local high temperature. In combination with the explosion-proof hole on the battery shell, the pressure can be released in time when the internal pressure exceeds the limit, and the risk of fire or explosion can be effectively reduced.

[0045] In a second aspect, the application provides a composite battery control system of multiple types of battery monomers, which adopts the following technical solutions:

[0046] A composite battery control system of multiple types of battery monomers, comprising a processor, wherein the processor executes the steps of the composite battery control method of multiple types of battery monomers according to any one of the above.

[0047] In a third aspect, the application provides a storage medium, which adopts the following technical solutions:

[0048] A storage medium, wherein the storage medium stores a program, and the program is executed by a processor to implement the steps of the composite battery control method of multiple types of battery monomers according to any one of the above.

[0049] In summary, the application includes at least one of the following beneficial technical effects: through the flexible series combination control of multiple types of battery monomers, the capacity, working condition and other parameters are dynamically adjusted to adjust the charge and discharge voltage, monitoring period and battery combination mode, and the differential management strategy and safety protection design are matched, so that the voltage adaptation range of the battery pack is widened, the charge and discharge stability and flexibility are improved, the cooperative and efficient work of the lithium battery and the nickel-hydrogen battery is realized, the dependence on high-priced hardware is reduced to reduce the cost, and the battery life is prolonged and the safety risk is reduced through the equalization management and heat conduction enhancement. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 is a structural schematic diagram of a composite battery.

[0051] Figure 2 is a step diagram of a composite battery control method of multiple types of monomer batteries.

[0052] Reference signs: 1, battery shell; 2, heat-conducting liquid; 3, first lithium battery monomer; 4, second lithium battery monomer; 5, first nickel-hydrogen battery monomer; 6, explosion-proof hole; 7, positive electrode lead-out end; 8, negative electrode lead-out end. DETAILED DESCRIPTION

[0053] Embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings.

[0054] In the description of the present specification, the description of the terms "certain embodiments", "one embodiment", "some embodiments", "illustrative embodiments", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the described embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0055] The embodiments of the present application disclose a composite battery control method of multiple types of monomer batteries, referring to Figure 1 , based on a composite battery of multiple types of monomer batteries, the composite battery includes a battery shell 1, a heat-conducting liquid 2, a first lithium battery monomer 3, a second lithium battery monomer 4, a first nickel-hydrogen battery monomer 5, an explosion-proof hole 6, a positive electrode lead-out end 7 and a negative electrode lead-out end 8. Among them, the battery shell 1 is a whole packaging structure, the top is provided with an explosion-proof hole 6, which is used to release pressure when the internal pressure is over-limit, avoiding the shell from bursting; the heat-conducting liquid 2 filled in the shell can enhance the heat conduction efficiency between the monomer batteries, preventing local high temperature aggregation.

[0056] The first lithium battery monomer 3, the second lithium battery monomer 4 and the first nickel-hydrogen battery monomer 5 are all soft package structures, and the encapsulating material adopts a hot melt type plastic with a melting temperature not higher than 90 degrees Celsius, which makes the battery release part of the pressure through material softening when slightly heated, while avoiding material failure at high temperature. The length and width dimensions of the three are the same, and the positive and negative electrode plate sizes are consistent, which are arranged in the battery shell 1 in the order of the first lithium battery monomer 3, the first nickel-hydrogen battery monomer 5 and the second lithium battery monomer 4, ensuring the compactness of the structure and the convenience of heat conduction.

[0057] In terms of electrical connection, the negative electrode of the first lithium battery cell 3 is connected with the negative electrode lead-out end 8 as the negative electrode of the whole battery; the positive electrode is connected with the negative electrode of the first nickel-hydrogen battery cell 5, and the positive electrode of the first nickel-hydrogen battery cell 5 is connected with the negative electrode of the second lithium battery cell 4; the positive electrode of the second lithium battery cell 4 is connected with the positive electrode lead-out end 7 as the positive electrode of the whole battery, forming a series loop.

[0058] In terms of capacity, the first lithium battery cell 3 and the second lithium battery cell 4 have the same capacity, which is 1.2 times the capacity of the first nickel-hydrogen battery cell 5. The first nickel-hydrogen battery cell 5 adopts a liquid electrolyte structure, and 5% of a permeating agent is filled in the electrolyte, which can effectively improve the ion conduction efficiency and enhance the charge and discharge response speed.

[0059] The composite battery can realize safe charge and discharge control without a protection plate. The principle is that the first nickel-hydrogen battery cell 5 has a smaller capacity than the lithium battery cell: when discharging, the first nickel-hydrogen battery cell 5 is discharged first, the voltage jump drops, the voltage of the whole battery pack drops sharply, and the discharge is naturally stopped to avoid over-discharge of the lithium battery cell; when charging, the first nickel-hydrogen battery cell 5 is fully charged first, the voltage jump rises, and the charging current is naturally eliminated to prevent overcharge of the lithium battery cell, which reduces the cost and overcomes the conduction loss of the power transistor of the protection plate.

[0060] Meanwhile, the battery has a self-extinguishing and fire-retardant function. When the lithium battery cell heats up and swells, it will squeeze the soft package of the first nickel-hydrogen battery cell 5, causing it to enter a high internal resistance mode due to electrolyte loss, which greatly reduces the charge and discharge current to avoid further thermal runaway of the lithium battery; and the strong alkaline electrolyte of the nickel-hydrogen battery enters the damaged lithium battery cell, which will damage and passivate the organic neutral electrolyte, and stop the lithium metal reaction, thereby essentially eliminating the fire hazard.

[0061] The embodiment of the application discloses a composite battery control method of multiple types of single battery cells, referring to Figure 1 and Figure 2 , based on the composite battery with the above structure, comprising the following steps:

[0062] The system obtains the voltage parameters of the three single battery cells in real time, that is, the first voltage of the first lithium battery cell 3, the second voltage of the second lithium battery cell 4, and the third voltage of the first nickel-hydrogen battery cell 5, and calculates the sum of the first voltage and the second voltage as the lithium battery voltage sum.

[0063] In the charging process, when receiving the charging instruction, the first lithium battery cell 3 and the second lithium battery cell 4 are directly connected in series for charging. If the lithium battery voltage value is greater than the preset charging voltage value at this time, the system will automatically adjust the series structure, connect the first lithium battery cell 3 or the second lithium battery cell 4 with the first nickel-hydrogen battery cell 5 in series, and then connect them into the charging circuit. By introducing the voltage characteristics of the nickel-hydrogen battery, the actual charging voltage borne by the lithium battery cell can be effectively reduced, and the risk of overcharging caused by excessively high voltage can be avoided.

[0064] In the discharging process, after receiving the discharging instruction, the first lithium battery cell 3 and the second lithium battery cell 4 are also directly connected in series for discharging. If the lithium battery voltage value is less than the preset discharging voltage value, the system will connect the first lithium battery cell 3 or the second lithium battery cell 4 with the first nickel-hydrogen battery cell 5 in series, and then connect them into the discharging circuit. With the help of the discharging voltage supplement of the nickel-hydrogen battery, the overall discharging voltage can be ensured to be stable within the device requirement range, and the device power failure or performance degradation caused by excessively low voltage can be avoided.

[0065] The control method realizes flexible series combination control of different types of single battery cells. In the charging and discharging process, the series structure is dynamically adjusted according to the comparison result of the lithium battery cell voltage value and the preset voltage value, which can not only fully utilize the high-efficiency charging and discharging characteristics of the lithium battery when the voltage meets the requirements, but also supplement and adjust with the characteristics of the nickel-hydrogen battery when the voltage is insufficient or excessively high, thereby realizing the collaborative work of multiple types of single battery cells.

[0066] In the present embodiment, the structure of the first lithium battery cell 3, the second lithium battery cell 4 and the first nickel-hydrogen battery cell 5 in series is adopted, and the first nickel-hydrogen battery cell 5 is located between the first lithium battery cell 3 and the second lithium battery cell 4, forming a "lithium battery-nickel-hydrogen battery-lithium battery" intermediate layout form.

[0067] When charging or discharging, the first nickel-hydrogen battery cell 5 located in the middle can more evenly intervene in the voltage adjustment process. For example, when charging, if the lithium battery voltage value is too high, the nickel-hydrogen battery needs to be introduced for voltage division, and the nickel-hydrogen battery in the middle position can form voltage buffering for the lithium battery cells on both sides at the same time, avoiding that a lithium battery on one side excessively bears the voltage division function due to being connected with the nickel-hydrogen battery in series. When discharging, if the nickel-hydrogen battery needs to be supplemented, the intermediate layout can also make the supplementing effect more evenly act on the lithium batteries on both sides, preventing a lithium battery on one side from being excessively discharged due to insufficient voltage.

[0068] Through this uniform participation adjustment mode, the electrochemical loss of a certain lithium battery monomer caused by long-term excessive voltage burden, such as positive electrode material structure degradation and electrolyte decomposition, can be effectively avoided, thereby balancing the working load of the three monomers, reducing the premature aging problem caused by uneven load of local monomers, and ultimately helping to prolong the cycle service life of the entire battery pack and improve the long-term use stability of the composite battery.

[0069] In the composite battery control method of the present application, an optimization strategy based on dynamic adjustment of the discharge voltage of the lithium battery capacity is adopted, and the specific method further includes the following steps:

[0070] A first period, for example 1 hour, is pre-set, which can be flexibly adjusted according to the battery use scene, and in each first period, the sum of the capacities of the first lithium battery monomer 3 and the second lithium battery monomer 4 is detected and calculated in real time by the battery management module, which is taken as the current lithium battery capacity. On this basis, the preset discharge voltage value is dynamically adjusted according to the "anti-correlation adjustment" principle; when the calculated lithium battery capacity is large (such as the remaining capacity exceeding 70%), the system automatically reduces the discharge voltage value, for example from the initial 3.7V to 3.5V; and when the lithium battery capacity is small (such as the remaining capacity being less than 30%), the discharge voltage value is increased, for example from 3.7V to 3.9V.

[0071] When the lithium battery capacity is sufficient, a lower discharge voltage can reduce the chemical reaction rate inside the battery, avoid unnecessary losses such as excessive lithium stripping of the positive electrode material and accelerated decomposition of the electrolyte caused by high voltage and strong discharge, and delay battery aging; and when the capacity is insufficient, appropriately increasing the discharge voltage can enhance the output capacity of the battery, ensure that the discharge current can still be maintained stable under the condition of limited remaining capacity, and protect the normal operation of the external device, for example, to avoid sudden shutdown of the device caused by voltage drop.

[0072] In the composite battery control method of the present application, for the management of the first nickel-hydrogen battery monomer 5, an optimization strategy based on dynamic adjustment of the capacity can also be adopted, and the specific method further includes the following steps:

[0073] A second period is pre-set, which can be set according to the characteristics and use scene of the nickel-hydrogen battery, for example 2 hours, which can be the same as or different from the first period, and in each second period, the real-time capacity of the first nickel-hydrogen battery monomer 5 is calculated by the corresponding detection module, which is taken as the basis for judging the capacity of the nickel-hydrogen battery.

[0074] Based on the capacity data, adjustment can be made in two ways:

[0075] The first is to adjust the preset charging voltage value according to the capacity of the nickel-hydrogen battery in an inverse correlation manner. When the capacity of the nickel-hydrogen battery is detected to be large, such as when the remaining power is above 80%, the system will automatically reduce the preset charging voltage value, such as from the initial 1.5V to 1.3V, to avoid the risk of overcharging caused by high voltage charging and reduce unnecessary energy loss; when the capacity of the nickel-hydrogen battery is small, such as when the remaining power is less than 20%, the preset charging voltage value is increased, for example, to 1.7V, to drive the charging process through a higher voltage to ensure charging efficiency and allow the battery to quickly replenish power.

[0076] The second adjustment method is to adjust the number of nickel-hydrogen batteries connected in parallel with the first nickel-hydrogen battery cell 5 according to the capacity of the nickel-hydrogen battery in a positive correlation manner. When the capacity of the nickel-hydrogen battery is small, it indicates that the current power supply capacity is insufficient, at which time the number of parallel nickel-hydrogen batteries is increased, such as from 1 to 3, to improve the total capacity and power supply capacity by connecting multiple batteries in parallel; when the capacity of the nickel-hydrogen battery is large, the power supply capacity is sufficient, so the number of parallel nickel-hydrogen batteries is reduced, for example, from 3 to 1, to avoid energy waste and circuit burden caused by too many batteries connected in parallel.

[0077] Through such periodic detection and dynamic adjustment, the nickel-hydrogen battery can be in a reasonable working mode under different capacity states, focusing on safety and energy saving when the capacity is sufficient, and ensuring charging efficiency and power supply capacity when the capacity is insufficient, further improving the stability and adaptability of the composite battery system.

[0078] In the composite battery control method of the present application, the monitoring period can also be optimized through dynamic evaluation of the working conditions of the lithium battery, and the specific method further includes the following steps:

[0079] The energy usage speed and usage temperature of the first lithium battery cell 3 and the second lithium battery cell 4 are obtained in real time. The energy usage speed reflects the current discharge or charging rate of the lithium battery, and the usage temperature reflects the heating state of the battery during operation. Then, a working condition evaluation value is calculated according to a preset formula, i.e. working condition evaluation value = ω1 × (vt / v_max) + ω2 × (Tt / T_max). Here, vt is the current energy usage speed, v_max is the maximum energy usage speed set according to the performance of the lithium battery; Tt is the current usage temperature, and T_max is the preset maximum allowable usage temperature. Once this temperature is exceeded, the battery may face a safety risk. ω1 and ω2 are weight coefficients of the energy usage speed and usage temperature, respectively, and their sum is 1. The values of ω1 and ω2 can be adjusted according to the emphasis on these two parameters in actual application, such as increasing the value of ω2 appropriately when used in a high-temperature environment. The two normalized processing terms (vt / v_max) and (Tt / T_max) can convert parameters of different units into values between 0 and 1, ensuring the reasonableness and comparability of the calculation results.

[0080] After obtaining the working condition evaluation value, the system will adjust the first period in anti-correlation according to the value. When the working condition evaluation value is large, it means that the current lithium battery is in a relatively harsh working condition, for example, the energy use speed is too fast and close to v_max, or the use temperature is too high and close to T_max. At this time, the first period will be shortened accordingly, such as from the original 1 hour to 30 minutes, so as to more frequently monitor the capacity and other states of the lithium battery, and timely adjust the discharge voltage value, so as to quickly discover and respond to possible abnormalities of the battery in harsh working conditions, and ensure the safety and stability of the system. When the working condition evaluation value is small, it indicates that the lithium battery is in a gentle working condition, the energy use speed is moderate, and the temperature is normal. At this time, the first period will be extended, such as to 2 hours, so as to reduce unnecessary calculation and adjustment operations, reduce the energy consumption and calculation load of the system, and realize the rational use of resources.

[0081] In the composite battery control method of the present application, for the state monitoring period of the first nickel-hydrogen battery monomer 5, a dynamic adjustment strategy based on the use depth range can be used, and the specific method includes the following steps:

[0082] The key voltage data of the first nickel-hydrogen battery monomer 5 in multiple charge and discharge cycles are continuously recorded. On the one hand, the voltage value at the beginning of use after each charge is recorded, that is, the beginning use voltage value (for example, the voltage is 1.45V after a certain charge, and 1.43V next time, etc.); On the other hand, the end use voltage value before each charge is recorded, for example, the voltage is 1.05V after a certain discharge, and 1.03V next time, etc.

[0083] After accumulating a certain number of sample data, such as 10 charge and discharge cycles, the system will process these data: calculate the average value according to multiple beginning use voltage values to obtain a comprehensive high voltage value, assuming that the average value of 10 data is 1.44V; Similarly, calculate the average value according to multiple end use voltage values to obtain a comprehensive low voltage value, assuming that the average value of 10 data is 1.04V. The actual use depth range of the first nickel-hydrogen battery monomer 5 is formed by the comprehensive high voltage value and the comprehensive low voltage value, such as 1.04V~1.44V.

[0084] Compare the actual use depth range with the preset standard use range (set according to the performance parameters of nickel-hydrogen battery, for example, 1.0V~1.45V) to calculate the range overlap value. The calculation of the overlap value can be determined by the ratio of the length of the overlapping interval to the total length of the standard range; For example, the overlapping interval of the actual range 1.04V~1.44V and the standard range 1.0V~1.45V is 1.04V~1.44V, the length is 0.4V, and the total length of the standard range is 0.45V, so the overlap value is 0.4 / 0.45≈0.89.

[0085] The second period is positively correlated with the range coincidence degree value. When the coincidence degree value is high (0.89 as described above), it indicates that the use state of the nickel-hydrogen battery deviates little from the standard state, and the second period is appropriately extended, for example, from 2 hours to 3 hours, to reduce the unnecessary capacity monitoring frequency and reduce the system operation load and energy consumption; when the coincidence degree value is low, for example, the actual use range is 0.95V~1.3V, and the coincidence degree value with the standard range is only 0.5, indicating that the use state of the battery deviates from the standard, and there may be overcharge or overdischarge risk, and the second period is shortened, for example, from 2 hours to 1 hour, to capture the capacity change in time through high-frequency monitoring, so as to quickly adjust the charging voltage or the number of parallel connections, and ensure the stable work of the nickel-hydrogen battery.

[0086] In the composite battery control method of the present application, for the capacity equalization management of the first lithium battery monomer 3 and the second lithium battery monomer 4, a hierarchical regulation and repair strategy can be adopted, and the specific method includes the following steps:

[0087] The real-time capacity of the first lithium battery monomer 3 (i.e. the first capacity, such as 2800mAh in a certain detection) and the real-time capacity of the second lithium battery monomer 4 (i.e. the second capacity, such as 2600mAh in a certain detection) are detected regularly, and the capacity difference between the two is calculated, for example, 2800mAh-2600mAh=200mAh. Then, combined with the preset reference difference, the nominal capacity difference range of the lithium battery monomer is set, for example, 300mAh, and the capacity unevenness is calculated by the formula "capacity unevenness=capacity difference / reference difference", for example, 200mAh / 300mAh≈0.67.

[0088] If the calculated capacity unevenness is less than the preset reference unevenness, for example, the reference unevenness is set to 0.8, the discharge voltage value is adjusted according to the inverse correlation principle: the greater the capacity unevenness, that is, the closer the capacity difference between the two batteries to the reference difference, the greater the adjustment range of the discharge voltage value. For example, when the unevenness is 0.67, the discharge voltage of the first lithium battery monomer 3 with higher capacity can be appropriately reduced by 0.1V, and the discharge voltage of the second lithium battery monomer 4 with lower capacity can be appropriately increased by 0.1V, so as to balance the output performance of the two batteries through voltage compensation, and avoid overdischarge of the battery with higher capacity and insufficient discharge of the battery with lower capacity.

[0089] If the capacity unevenness exceeds the preset reference unevenness, such as detecting that the first capacity is 3000mAh, the second capacity is 2400mAh, the capacity difference is 600mAh, and the unevenness = 600 / 300 = 2.0 > 0.8, the emergency repair mechanism is triggered: the system first switches out the first nickel-hydrogen battery monomer 5 from the working circuit through the circuit switching to avoid its participation in charging and discharging when the lithium battery capacity is seriously unbalanced and aggravate the loss; then start the battery equalization repair program, through the special equalization circuit to charge or discharge the two lithium battery monomers, such as supplementing the second lithium battery monomer 4 to 2800mAh, or discharging the first lithium battery monomer 3 to 2800mAh, until the capacity difference of the two is reduced to the reference difference range, such as ≤300mAh.

[0090] Through the hierarchical strategy, when the capacity difference is small, the system can be maintained stable operation through fine voltage adjustment, preventing small differences from gradually accumulating into big problems, and when the difference exceeds the standard, the auxiliary battery can be cut off in time and repaired, avoiding the risk of accelerated plate aging and accelerated capacity decay of the two lithium batteries due to long-term unbalanced work, effectively prolonging the overall service life of the lithium battery pack.

[0091] In the composite battery structure design of the present application, specific optimization schemes are adopted for the first nickel-hydrogen battery monomer 5 and overall safety protection, and the specific implementation is as follows:

[0092] The first nickel-hydrogen battery monomer 5 adopts a liquid electrolyte structure, and 5% of a penetrant such as a specific type of surfactant is proportionally filled into the electrolyte. It can significantly improve the wettability and ion conduction ability of the electrolyte; the penetrant can reduce the interfacial tension between the electrolyte and the electrode material, so that the electrolyte covers the electrode surface more uniformly, and at the same time promotes the migration efficiency of ions between the electrode and the electrolyte. In practical application, this structure can improve the charge and discharge response speed of the nickel-hydrogen battery by about 10%-15%, for example, in the discharge scene requiring rapid pressure compensation, it can shorten the response time of voltage regulation, ensure smoother cooperation with lithium batteries, and avoid voltage fluctuations caused by nickel-hydrogen battery response lag.

[0093] The shell of the composite battery is filled with a heat-conducting liquid 2, such as silicon oil or a special battery cooling liquid, and the filling amount is preferably sufficient to completely wet the surface of each monomer battery. The heat-conducting liquid 2 can quickly transfer the heat generated by the first lithium battery monomer 3, the second lithium battery monomer 4 and the first nickel-hydrogen battery monomer 5 during operation to the entire shell through convection and conduction, avoiding local heat accumulation. For example, when the lithium battery generates a lot of heat due to high-rate discharge, the heat-conducting liquid 2 can diffuse the heat from the lithium battery surface to the shell heat dissipation surface, reducing the local temperature by 5-8℃, effectively alleviating the impact of high temperature on battery performance.

[0094] At the same time, the battery shell 1 top is provided with an explosion-proof hole 6, which is located at the center of the battery internal monomer arrangement, and the hole diameter is designed according to the shell volume and the preset safety pressure value, such as 3-5mm in diameter, and the hole is covered with a thin aluminum sealing sheet (0.1-0.2mm thick). When the pressure in the battery rises to the preset threshold (such as 0.3MPa) due to abnormal reaction (such as the initial stage of lithium battery thermal runaway), the sealing sheet will be broken by the pressure, and the internal gas will be quickly released through the explosion-proof hole 6, so that the internal pressure of the shell is reduced to the safety range within 1-2 seconds, avoiding the shell from being cracked due to excessive pressure, and blocking the escalation of the explosion risk from the structure.

[0095] Through the above design, the performance synergy of the nickel-hydrogen battery is improved by optimizing the electrolyte, and a double safety protection system is constructed by means of the heat-conducting liquid 2 and the explosion-proof hole 6, which greatly improves the safety and reliability of the system while ensuring the working efficiency of the composite battery.

[0096] The application also discloses a composite battery control system of multiple types of monomer batteries, which comprises a processor, and the processor executes the steps of the composite battery control method of the multiple types of monomer batteries according to any one of the above.

[0097] The application also discloses a storage medium, which stores a program, and the program is executed by a processor to realize the steps of the composite battery control method of the multiple types of monomer batteries according to any one of the above.

[0098] Although the embodiments of the application have been shown and described above, it should be understood that the above embodiments are exemplary and cannot be understood as limiting the application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the application.

Claims

1. A composite battery control method of a plurality of types of single batteries, characterized by, The method comprises the following steps: Based on the set first lithium battery cell (3), second lithium battery cell (4) and first nickel hydrogen battery cell (5); The first voltage of the first lithium battery cell (3), the second voltage of the second lithium battery cell (4) and the third voltage of the first nickel hydrogen battery cell (5) are obtained; The sum of the first voltage and the second voltage is calculated as the lithium battery voltage sum; Based on the obtained charging instruction, the first lithium battery cell (3) and the second lithium battery cell (4) are connected in series for charging; if the lithium battery voltage sum is greater than the preset charging voltage value, the first lithium battery cell (3) or the second lithium battery cell (4) is connected in series with the first nickel hydrogen battery cell (5) for charging; Based on the obtained discharging instruction, the first lithium battery cell (3) and the second lithium battery cell (4) are connected in series for discharging; If the lithium battery voltage sum is less than the preset discharging voltage value, the first lithium battery cell (3) or the second lithium battery cell (4) is connected in series with the first nickel hydrogen battery cell (5) for discharging; The first lithium battery cell (3), the second lithium battery cell (4) and the first nickel hydrogen battery cell (5) are connected in series, and the first nickel hydrogen battery cell (5) is located between the first lithium battery cell (3) and the second lithium battery cell (4); When the lithium battery cell heats and swells, it will squeeze and break the soft package of the first nickel hydrogen battery cell (5).

2. The composite battery control method of a plurality of types of single cells according to claim 1, characterized by, The method further comprises: In a set first period, the total capacity of the capacity of the first lithium battery cell (3) and the capacity of the second lithium battery cell (4) is calculated as the lithium battery capacity; According to the lithium battery capacity, the discharging voltage value is inversely related to the lithium battery capacity; the smaller the lithium battery capacity, the greater the discharging voltage value.

3. The composite battery control method of a plurality of types of single cells according to claim 1, characterized by, The method further comprises: According to a set second period, the capacity of the first nickel hydrogen battery cell (5) is calculated as the nickel hydrogen battery capacity; According to the nickel hydrogen battery capacity, the preset charging voltage value is inversely related to the nickel hydrogen battery capacity; the greater the nickel hydrogen battery capacity, the smaller the preset charging voltage value; the smaller the nickel hydrogen battery capacity, the greater the preset charging voltage value; Alternatively, according to the nickel hydrogen battery capacity, the number of nickel hydrogen batteries connected in parallel with the first nickel hydrogen battery cell (5) is positively related to the nickel hydrogen battery capacity; the smaller the nickel hydrogen battery capacity, the greater the number of nickel hydrogen batteries connected in parallel; the greater the nickel hydrogen battery capacity, the smaller the number of nickel hydrogen batteries connected in parallel.

4. The composite battery control method of a plurality of types of single cells according to claim 2, characterized by, The method further comprises: The energy use speed and use temperature of the first lithium battery cell (3) and the second lithium battery cell (4) are obtained; According to the energy use speed and use temperature, a working condition evaluation value is calculated, the working condition evaluation value = ω1 × (vt / v_max) + ω2 × (Tt / T_max); wherein: vt is the current energy use speed, v_max is the preset maximum energy use speed; Tt is the current use temperature, T_max is the preset maximum allowable use temperature; ω1 and ω2 are weight coefficients of the energy use speed and use temperature respectively, and ω1 + ω2 = 1; (vt / v_max) and (Tt / T_max) are normalization processing items, and the value range is 0~1; The first period is inversely adjusted according to the working condition evaluation value; the greater the working condition evaluation value, the shorter the corresponding first period; the smaller the working condition evaluation value, the longer the corresponding first period.

5. The composite battery control method of a plurality of types of single cells according to claim 3, characterized by, Record the starting use voltage value of the plurality of first nickel-hydrogen battery cells (5) after charging ends; Record the ending use voltage value of the plurality of first nickel-hydrogen battery cells (5) when charging starts; Calculate the comprehensive high voltage value according to the plurality of starting use voltage values; Calculate the comprehensive low voltage value according to the plurality of ending use voltage values; Combine the comprehensive high voltage value and the comprehensive low voltage value to obtain a use depth range; Calculate the range coincidence degree value of the use depth range and the preset standard use range; Positively adjust the second period according to the range coincidence degree value; the higher the range coincidence degree value, the longer the second period; the lower the range coincidence degree value, the shorter the second period.

6. The composite battery control method of claim 2, wherein Detect the capacity of the first lithium battery cell (3) as a first capacity and detect the capacity of the second lithium battery cell (4) as a second capacity; Calculate the capacity difference value according to the first capacity and the second capacity; Calculate the capacity unevenness according to the capacity difference value and the preset reference difference value; If the capacity unevenness is less than the preset reference unevenness, inversely adjust the discharge voltage value according to the capacity unevenness; Otherwise, cut the first nickel-hydrogen battery cell (5) out of the circuit and perform battery equalization repair on the first lithium battery cell (3) and the second lithium battery cell (4).

7. The composite battery control method of a plurality of types of single cells according to claim 1, characterized by, The first nickel-hydrogen battery cell (5) adopts a liquid electrolyte structure, which contains 5% of a penetrant; the composite battery further includes a heat-conducting liquid (2) for enhancing heat conduction between battery cells and an explosion-proof hole (6) provided on the battery shell (1) and capable of releasing pressure when the internal pressure exceeds a limit.

8. A hybrid battery control system for a plurality of types of single batteries, characterized by, The processor executes the steps of the composite battery control method of the multiple-type single-cell battery according to any one of claims 1-7.

9. A storage medium, characterized by The storage medium stores a program, which is executed by the processor to implement the steps of the composite battery control method of the multiple-type single-cell battery according to any one of claims 1-7.

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