Composite battery control method and system for multiple types of single batteries and storage medium

Abstract

The invention relates to the technical field of energy storage batteries, and discloses a composite battery control method and system for multi-type single batteries and a storage medium, and the method comprises the steps: obtaining the voltage of each single battery based on a first lithium battery single body, a second lithium battery single body and a first nickel-metal hydride battery single body, and calculating the voltage sum value of the lithium batteries; during charging, the two lithium batteries are connected in series for charging, and if the voltage sum value of the two lithium batteries is larger than a preset charging voltage value, any lithium battery and the nickel-metal hydride battery are connected in series for charging; during discharging, the two lithium batteries are connected in series for discharging, and if the voltage sum value is smaller than a preset discharging voltage value, any lithium battery and the nickel-metal hydride battery are connected in series for discharging. According to the method, different types of single batteries are flexibly connected in series and combined, so that the voltage application range of the battery pack is widened, the charging and discharging stability and flexibility are improved, the dependence on high-price hardware is reduced, and the overall cost is reduced.

Description

Technical Field

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

[0002] Lithium-ion battery fires stem from the coupling of internal electrochemical reactions and structural characteristics. Under abnormal operating conditions, such as overcharging and short-circuiting, the battery's positive electrode material releases oxygen, which reacts violently with lithium metal deposited from the negative electrode, releasing large amounts of heat. Furthermore, the electrolyte, often a flammable carbonate solvent, rapidly vaporizes and decomposes upon heating, producing flammable gases. When the internal temperature of the battery exceeds the critical boiling point of the electrolyte, the gas pressure surges, causing the battery shell to rupture. The flammable gases, when mixed with air and exposed to high temperatures or sparks, can ignite or even explode. This chain reaction can quickly spread to the battery pack, further exacerbating the incident.

[0003] Current temperature control and fire prevention measures for lithium-ion batteries are primarily categorized as active and passive. Active prevention involves using a battery management system to monitor the voltage and temperature of individual cells in real time, preventing overcharging through balanced charging, and employing air, liquid, or direct cooling systems to initiate heat dissipation when temperatures exceed thresholds. Passive protection relies on flame-retardant materials in the battery casing and fireproof insulation between the cells.

[0004] In active temperature control systems, components like heat exchangers and circulation pumps for liquid / direct cooling are 30%-50% more expensive than those for air cooling. They also require additional temperature sensors and control modules. High-precision chips for BMS balancing functions can cost 2-3 times more than standard chips. Passive protection features like flame-retardant materials and fireproof insulation pads cost over 40% more than conventional materials. The installation and regular replacement of fire extinguishing devices account for an average of 8%-12% of the total energy storage system cost annually. Existing temperature control and fire prevention measures present significant cost challenges. Summary of the Invention

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

[0006] In a first aspect, the present application provides a composite battery control method for multiple types of single cells, which adopts the following technical solution: A composite battery control method for multiple types of single cells comprises the following steps: Based on the set first lithium battery cell, second lithium battery cell and first nickel-metal hydride battery cell; Obtaining a first voltage of a first lithium battery cell, a second voltage of a second lithium battery cell, and a third voltage of a first nickel-metal hydride battery cell; Calculate the sum of the first voltage and the second voltage as the lithium battery voltage sum; Based on the obtained charging instruction, the first lithium battery cell and the second lithium battery cell are connected in series and then charged; if the sum of the lithium battery voltages is greater than the preset charging voltage value, the first lithium battery cell or the second lithium battery cell is connected in series with the first nickel-metal hydride battery cell and then charged; Based on the obtained discharge instruction, the first lithium battery cell and the second lithium battery cell are connected in series and then discharged; if the sum of the lithium battery voltages is less than the preset discharge voltage value, the first lithium battery cell or the second lithium battery cell is connected in series with the first nickel-metal hydride battery cell and then discharged.

[0007] By adopting the above technical solution, different types of single cells (lithium batteries and nickel-metal hydride batteries) are flexibly controlled in series combination. During the charging or discharging process, the series structure is dynamically adjusted based on the comparison result of the voltage sum value of the lithium battery cell and the preset voltage value. This can not only utilize the efficient charging and discharging characteristics of the lithium battery when the voltage meets the requirements, but also use the characteristics of the nickel-metal hydride battery for supplementary adjustment when the voltage is insufficient or too high, thereby realizing the coordinated operation of multiple types of single cells, effectively broadening the voltage adaptability range of the battery pack, and improving the charging and discharging stability and flexibility of the battery system under different working conditions. At the same time, there is no need to rely on high-precision chips or complex temperature control hardware, which helps to reduce overall costs.

[0008] Optionally, the first lithium battery cell, the second lithium battery cell and the first nickel-metal hydride battery cell are arranged in series, and the first nickel-metal hydride battery cell is located between the first lithium battery cell and the second lithium battery cell.

[0009] By adopting the above technical solution, the intermediate layout allows the nickel-metal hydride batteries to participate in voltage regulation more evenly during the charging and discharging process, avoiding the aggravated loss of a certain lithium battery cell due to excessive voltage, which is conducive to balancing the workload of each single cell and extending the service life of the entire battery pack.

[0010] Optionally, the method further comprises: In a set first cycle, the total capacity of the first lithium battery cell and the capacity of the second lithium battery cell is calculated to obtain the lithium battery capacity; The discharge voltage value is adjusted inversely according to the capacity of the lithium battery. The larger the capacity of the lithium battery, the smaller the discharge voltage value; the smaller the capacity of the lithium battery, the larger the discharge voltage value.

[0011] By adopting the above technical solution, the discharge voltage value is lowered when the lithium battery capacity is large, and the discharge voltage value is increased when the capacity is small. This can dynamically adapt to the actual capacity state of the battery, avoid unnecessary losses caused by excessively high discharge voltage when the capacity is sufficient, and ensure discharge efficiency and stability by increasing the discharge voltage when the capacity is insufficient.

[0012] Optionally, the method further comprises: Calculating the capacity of the first nickel-metal hydride battery cell according to the set second cycle as the nickel-metal hydride battery capacity; The preset charging voltage value is adjusted inversely according to the capacity of the nickel-hydrogen battery; the larger the capacity of the nickel-hydrogen battery, the smaller the preset charging voltage value; the smaller the capacity of the nickel-hydrogen battery, the larger the preset charging voltage value; Alternatively, the number of NiMH batteries connected in parallel with the first NiMH battery cell is adjusted according to the positive correlation with the NiMH battery capacity; the smaller the NiMH battery capacity, the more NiMH batteries connected in parallel; the larger the NiMH battery capacity, the fewer NiMH batteries connected in parallel.

[0013] By adopting the above technical solution, when the capacity of the nickel-hydrogen battery is large, the charging voltage is lowered and the number of parallel connections is reduced, and when the capacity is small, the charging voltage is increased or the number of parallel connections is increased. This can avoid the risk of overcharging or reduce unnecessary energy loss when the capacity is sufficient, and ensure charging efficiency and power supply capacity by increasing the voltage or increasing the number of parallel connections when the capacity is insufficient.

[0014] Optionally, the method further comprises: Obtaining energy usage speed and usage temperature of the first lithium battery cell and the second lithium battery cell; The operating condition evaluation value is calculated based on the energy usage rate and operating temperature. The operating condition evaluation value = ω1×(vt / v_max)+ω2×(Tt / T_max); where: vt is the current energy usage rate, v_max is the preset maximum energy usage rate; Tt is the current operating temperature, and T_max is the preset maximum allowable operating temperature; ω1 and ω2 are the weight coefficients of energy usage rate and operating temperature, respectively, and ω1+ω2=1; (vt / v_max) and (Tt / T_max) are normalization processing items, with a value range of 0~1; The first period is adjusted inversely according to the operating condition evaluation value; the larger the operating condition evaluation value is, the shorter the corresponding first period is; the smaller the operating condition evaluation value is, the longer the corresponding first period is.

[0015] By adopting the above technical solution, the cycle is shortened when the working conditions are severe (the evaluation value is large) to monitor and adjust the lithium battery status more frequently, and the cycle is extended when the working conditions are mild (the evaluation value is small) to reduce unnecessary calculations and adjustments. This can not only detect and respond to battery abnormalities in a timely manner through high-frequency monitoring under harsh working conditions to ensure system safety and stability, but also reduce unnecessary energy consumption and computing load under mild working conditions.

[0016] Optionally, recording the starting voltage values ​​of the plurality of first nickel-metal hydride battery cells after charging is completed; Recording the end-of-use voltage values ​​of the plurality of first nickel-metal hydride battery cells when charging begins; A comprehensive high voltage value is calculated based on multiple starting voltage values; A comprehensive low voltage value is calculated based on multiple end-of-use voltage values; The use depth range is obtained according to the combination of the comprehensive high voltage value and the comprehensive low voltage value; Calculate the degree of overlap between the use depth range and the preset standard use range; The second period is positively adjusted according to the range overlap value. The higher the range overlap value is, the longer the second period is; the lower the range overlap value is, the shorter the second period is.

[0017] By adopting the above technical solution, the cycle is extended to reduce unnecessary monitoring when the overlap is high, and the cycle is shortened to strengthen monitoring when the overlap is low. This can not only reduce the system operating load and energy consumption when the battery usage status is stable, but also detect abnormalities and make adjustments in time through high-frequency monitoring when the usage status deviates from the standard, thereby realizing dynamic adaptation of nickel-hydrogen battery status monitoring.

[0018] Optionally, the capacity of the first lithium battery cell is detected to be a first capacity and the capacity of the second lithium battery cell is detected to be a second capacity; calculating a capacity difference based on the first capacity and the second capacity; The capacity unevenness is calculated based on the capacity difference and the preset reference difference; If the capacity unevenness is less than the preset reference unevenness, the discharge voltage value is adjusted inversely according to the capacity unevenness; otherwise, the first nickel-hydrogen battery cell is cut out of the circuit and the first lithium battery cell and the second lithium battery cell are repaired by cell balancing.

[0019] By adopting the above technical solution, the discharge voltage value is adjusted in an anti-correlated manner to balance the performance when the unevenness is low. When the unevenness exceeds the limit, the nickel-metal hydride battery is cut out and balanced repair is performed. This can maintain stable system operation through voltage regulation when there is a slight capacity difference, avoiding the accumulation and aggravation of small differences. When the difference is significant, the repair mechanism can be activated in time to prevent the battery cells from suffering life degradation or safety risks due to long-term unbalanced operation.

[0020] Optionally, the first nickel-metal hydride battery cell adopts a liquid electrolyte structure, which is filled with 5% of a penetrant; the composite battery also includes a heat-conducting liquid for enhancing heat conduction between battery cells and an explosion-proof hole arranged on the battery shell to release pressure when the internal pressure exceeds the limit.

[0021] By adopting the above-mentioned technical solution and using a liquid electrolyte structure containing 5% penetrant for the first nickel-metal hydride battery cell, the ion conduction efficiency of the electrolyte can be improved, the charging and discharging performance and response speed of the nickel-metal hydride battery can be enhanced, and the collaborative working effect with the lithium battery can be optimized; at the same time, the added thermal conductive fluid can enhance heat conduction between battery cells, accelerate heat diffusion to avoid local high temperature, and cooperate with the explosion-proof holes on the battery shell to release pressure in time when the internal pressure exceeds the limit, effectively reducing the risk of fire or explosion.

[0022] In a second aspect, the present application provides a composite battery control system for multiple types of single cells, which adopts the following technical solution: A composite battery control system for multiple types of single cells includes a processor, wherein the processor executes the steps of any one of the above-mentioned composite battery control methods for multiple types of single cells.

[0023] In a third aspect, the present application provides a storage medium that adopts the following technical solution: A storage medium stores a program, wherein the program, when executed by a processor, implements the steps of any one of the above-mentioned methods for controlling a composite battery of multiple types of single cells.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: through flexible series combination control of multiple types of single cells, dynamic adjustment of charging and discharging voltage, monitoring cycle and battery combination mode in combination with parameters such as capacity and operating conditions, and combined with differentiated management strategies and safety protection designs, it not only broadens the voltage adaptation range of the battery pack, improves the charging and discharging stability and flexibility, realizes the coordinated and efficient operation of lithium batteries and nickel-hydrogen batteries, but also reduces dependence on high-priced hardware to reduce costs. At the same time, through balanced management, thermal conduction enhancement and other means, it extends battery life and reduces safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of a composite battery.

[0026] Figure 2 The present invention is a step diagram of a composite battery control method for multiple types of single cells.

[0027] Figure numerals: 1. battery housing; 2. heat transfer liquid; 3. first lithium battery cell; 4. second lithium battery cell; 5. first nickel-metal hydride battery cell; 6. explosion-proof hole; 7. positive electrode lead-out terminal; 8. negative electrode lead-out terminal. DETAILED DESCRIPTION

[0028] Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings.

[0029] Throughout this specification, reference to the terms "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0030] The present application embodiment discloses a composite battery control method for multiple types of single cells, referring to Figure 1 The composite battery, based on multiple types of single cells, includes a battery case 1, a thermal conductive fluid 2, a first lithium battery cell 3, a second lithium battery cell 4, a first nickel-metal hydride battery cell 5, an explosion-proof vent 6, a positive electrode terminal 7, and a negative electrode terminal 8. The battery case 1 serves as the overall packaging structure, with an explosion-proof vent 6 on top to release pressure when the internal pressure exceeds the limit and prevent the case from bursting. The thermal conductive fluid 2 inside the case enhances heat conduction efficiency between the single cells and prevents localized high temperature accumulation.

[0031] The first lithium battery cell 3, the second lithium battery cell 4, and the first nickel-metal hydride battery cell 5 all have a soft-pack structure, encapsulated with a hot-melt plastic with a melting temperature no higher than 90 degrees Celsius. This design allows the material to soften and release some pressure when the battery heats up slightly, while also preventing material failure at high temperatures. All three cells have identical length and width dimensions, and their positive and negative plates are also the same size. They are tightly arranged within the battery casing 1, in the order of the first lithium battery cell 3, the first nickel-metal hydride battery cell 5, and the second lithium battery cell 4, ensuring a compact structure and convenient heat conduction.

[0032] In terms of electrical connection, the negative electrode of the first lithium battery cell 3 serves as the negative electrode of the entire battery and is connected to the negative electrode lead-out terminal 8; its positive electrode is connected to 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 to the negative electrode of the second lithium battery cell 4; the positive electrode of the second lithium battery cell 4 serves as the positive electrode of the entire battery and is connected to the positive electrode lead-out terminal 7 to form a series circuit.

[0033] The capacity of the first lithium battery cell 3 and the second lithium battery cell 4 is the same, and is 1.2 times that of the first nickel-metal hydride battery cell 5. The first nickel-metal hydride battery cell 5 uses a liquid electrolyte structure with a 5% penetrant in the electrolyte, which can effectively improve ion conduction efficiency and enhance charge and discharge response speed.

[0034] This composite battery can achieve safe charge and discharge control without a protection board. The principle is to utilize the characteristic that the capacity of the first nickel-metal hydride battery cell 5 is smaller than that of the lithium battery cell: during discharge, the first nickel-metal hydride battery cell 5 is discharged first, and the voltage jump drops, causing the voltage of the entire battery pack to drop significantly, naturally stopping discharge and preventing over-discharge of the lithium battery cell; during charging, the first nickel-metal hydride battery cell 5 is fully charged first, and the voltage jump increases, which naturally eliminates the charging current and prevents overcharging of the lithium battery cell. This not only reduces costs but also overcomes the conduction loss of the power transistor of the protection board.

[0035] The battery also features self-extinguishing and flame-retardant features. When a lithium-ion battery cell heats up and swells, it ruptures the soft pack of the first nickel-metal hydride battery cell 5, causing it to enter a high-resistance mode due to electrolyte loss. This significantly reduces charge and discharge currents and prevents further thermal runaway of the lithium-ion battery. The strong alkaline electrolyte of the nickel-metal hydride battery enters the damaged lithium-ion battery cell, destroying and passivating its organic neutral electrolyte, halting the lithium metal reaction and essentially eliminating the fire hazard.

[0036] The present application embodiment discloses a composite battery control method for multiple types of single cells, referring to Figure 1 and Figure 2 The composite battery based on the above structure includes the following steps: The system obtains the voltage parameters of three single cells in real time, namely 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-metal hydride battery cell 5, and calculates the sum of the first voltage and the second voltage as the lithium battery voltage sum value.

[0037] During the charging process, upon receiving a charge command, the first and second lithium-ion battery cells 3 and 4 are prioritized for direct series charging. If the total voltage of the lithium-ion battery cells detected at this time exceeds the preset charging voltage, the system automatically adjusts the series connection, connecting either the first or second lithium-ion battery cell 3 and the first nickel-metal hydride battery cell 5 in series before reconnecting them to the charging circuit. By incorporating the voltage characteristics of nickel-metal hydride batteries, the actual charging voltage experienced by the lithium-ion battery cells can be effectively reduced, avoiding the risk of overcharging due to excessive voltage.

[0038] During the discharge process, upon receiving a discharge command, the system prioritizes the direct series connection of the first and second lithium-ion battery cells 3 and 4. If the total voltage of the monitored lithium-ion batteries is less than the preset discharge voltage, the system connects the first or second lithium-ion battery cell 3 or 4 in series with the first nickel-metal hydride battery cell 5 and connects them to the discharge circuit. The nickel-metal hydride battery's discharge voltage supplement ensures that the overall discharge voltage remains within the device's required range, preventing power outages or performance degradation due to low voltage.

[0039] This control method enables flexible series control of different types of battery cells. During the charge and discharge process, the series structure is dynamically adjusted based on the comparison of the sum of the lithium battery cell voltages with the preset voltage value. This method not only fully utilizes the efficient charge and discharge characteristics of lithium batteries when the voltage meets the requirements, but also leverages the characteristics of nickel-metal hydride batteries for supplementary adjustment when the voltage is insufficient or too high, thus achieving the coordinated operation of multiple types of battery cells.

[0040] In this embodiment, a structure in which the first lithium battery cell 3, the second lithium battery cell 4 and the first nickel-metal hydride battery cell 5 are arranged in series is adopted, and the first nickel-metal hydride battery cell 5 is located between the first lithium battery cell 3 and the second lithium battery cell 4, forming an intermediate layout of "lithium battery-nickel-metal hydride battery-lithium battery".

[0041] During charging or discharging operations, the middle-positioned first nickel-metal hydride battery cell 5 allows for more uniform voltage regulation. For example, if the sum of the lithium battery voltages is too high during charging, requiring a nickel-metal hydride voltage divider, the middle nickel-metal hydride battery can simultaneously provide a voltage buffer for the lithium battery cells on both sides, preventing one side of the lithium battery from over-sharing due to being connected in series with the nickel-metal hydride battery. If the nickel-metal hydride battery needs to provide voltage boost during discharge, the middle-positioned arrangement also ensures a more balanced voltage boost across both lithium battery cells, preventing over-discharge due to insufficient voltage on one side.

[0042] This uniformly participated regulation method can effectively avoid the electrochemical loss of a lithium battery cell caused by long-term excessive voltage, such as degradation of the positive electrode material structure and decomposition of the electrolyte, thereby balancing the workload of the three single cells and reducing the premature aging problem of local cells caused by uneven load. Ultimately, it helps to extend the cycle life of the entire battery pack and improve the long-term stability of the composite battery.

[0043] In the composite battery control method of the present application, an optimization strategy for dynamically adjusting the discharge voltage based on the capacity of the lithium battery is adopted. The specific method further includes the following steps: A pre-set first cycle, for example, one hour, can be flexibly adjusted based on battery usage scenarios. During each first cycle, the battery management module detects and calculates the combined capacity of the first and second lithium battery cells 3 and 4 in real time, using this as the current lithium battery capacity. Based on this, the preset discharge voltage is dynamically adjusted according to the "anti-correlation regulation" principle. When the calculated lithium battery capacity is high (e.g., the remaining charge exceeds 70%), the system automatically lowers the discharge voltage, for example, from the initial 3.7V to 3.5V. When the lithium battery capacity is low (e.g., the remaining charge is less than 30%), the discharge voltage is increased, for example, from 3.7V to 3.9V.

[0044] When the lithium battery has sufficient capacity, a lower discharge voltage can reduce the chemical reaction rate inside the battery, avoid unnecessary losses such as excessive delithiation of the positive electrode material and accelerated decomposition of the electrolyte due to high-voltage discharge, and delay battery aging. When the capacity is insufficient, appropriately increasing the discharge voltage can enhance the battery's output capacity, ensuring that a stable discharge current can be maintained even when the remaining power is limited, ensuring the normal operation of external devices, such as avoiding sudden shutdown of the device due to a sudden voltage drop.

[0045] In the composite battery control method of the present application, an optimization strategy based on dynamic capacity adjustment may be adopted for the management of the first nickel-metal hydride battery cell 5. The specific method further includes the following steps: A second cycle is pre-set, which can be set according to the characteristics of the nickel-metal hydride battery and the usage scenario, for example, 2 hours, and can be the same as or different from the first cycle. In each second cycle, the real-time capacity of the first nickel-metal hydride battery cell 5 is calculated by the corresponding detection module and used as the basis for judging the capacity of the nickel-metal hydride battery.

[0046] Based on this capacity data, adjustments can be made in two ways: The first is to adjust the preset charging voltage value inversely according to the capacity of the NiMH battery. When the NiMH battery capacity is detected to be large, such as the remaining power is above 80%, the system will automatically lower the preset charging voltage value, for example, 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 NiMH battery capacity is small, such as the remaining power is less than 20%, the preset charging voltage value is increased, for example to 1.7V. The higher voltage drives the charging process, ensuring charging efficiency and allowing the battery to be replenished quickly.

[0047] The second adjustment method is to adjust the number of NiMH batteries connected in parallel with the first NiMH battery cell 5 based on the positive correlation with the NiMH battery capacity. When the NiMH battery capacity is low, indicating insufficient power supply capacity, the number of NiMH batteries connected in parallel is increased, for example, from one to three, thereby increasing the total capacity and power supply capacity by connecting multiple batteries in parallel. When the NiMH battery capacity is high, indicating sufficient power supply capacity, the number of NiMH batteries connected in parallel is reduced, for example, from three to one, to avoid energy waste and circuit burden caused by too many batteries connected in parallel.

[0048] Through such periodic detection and dynamic adjustment, nickel-hydrogen batteries can be kept 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.

[0049] In the composite battery control method of the present application, the monitoring cycle can also be optimized by dynamically evaluating the operating conditions of the lithium battery. The specific method further includes the following steps: The energy usage rate and operating temperature of the first and second lithium battery cells 3 and 4 are acquired in real time. The energy usage rate reflects the current discharge or charge rate of the lithium battery, while the operating temperature reflects the heating state of the battery during operation. The operating condition assessment value is then calculated according to a preset formula: operating condition assessment value = ω1 × (vt / v_max) + ω2 × (Tt / T_max). Here, vt is the current energy usage rate, v_max is the maximum energy usage rate set based on the lithium battery's performance, Tt is the current operating temperature, and T_max is the preset maximum allowable operating temperature. Exceeding this temperature may expose the battery to safety risks. ω1 and ω2 are weighting coefficients for energy usage rate and operating temperature, respectively, with their sum being 1. The emphasis on these two parameters can be adjusted based on the actual application. For example, the value of ω2 can be appropriately increased when used in high-temperature environments. The two normalization terms (vt / v_max) and (Tt / T_max) convert parameters with different units into values ​​between 0 and 1, ensuring the rationality and comparability of the calculation results.

[0050] After obtaining the working condition evaluation value, the system will perform anti-correlation adjustment on the first cycle according to the value. When the working condition evaluation value is large, it means that the current lithium battery is in a relatively bad working condition, such as the energy usage speed is too fast and close to v_max, or the operating temperature is too high and close to T_max. At this time, the first cycle will be shortened accordingly, for example, from the original 1 hour to 30 minutes, so as to monitor the capacity and other conditions of the lithium battery more frequently, and adjust the discharge voltage value in time, so as to quickly discover and respond to possible abnormalities of the battery under 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 smooth working condition, the energy usage speed is moderate and the temperature is normal. At this time, the first cycle will be extended, for example, to 2 hours. This can reduce unnecessary calculations and adjustment operations, reduce the energy consumption and computing load of the system, and achieve rational use of resources.

[0051] In the composite battery control method of the present application, a dynamic adjustment strategy based on the usage depth range can be adopted for the status monitoring cycle of the first nickel-metal hydride battery cell 5. The specific method includes the following steps: Continuously record key voltage data of the first nickel-metal hydride battery cell 5 during multiple charge and discharge cycles: on the one hand, record the voltage value when the battery is put into use after each charge is completed, that is, the starting voltage value (for example, the voltage is 1.45V after a certain charge, and 1.43V the next time, etc.); on the other hand, record the ending voltage value before each charge is started, for example, the voltage is 1.05V after a certain discharge, and 1.03V the next time, etc.

[0052] After accumulating a certain amount of sample data, such as 10 charge-discharge cycles, the system processes this data by calculating the average of multiple start-of-use voltage values ​​to obtain a composite high voltage value, assuming the average of the 10 data values ​​is 1.44V. Similarly, the system calculates the average of multiple end-of-use voltage values ​​to obtain a composite low voltage value, assuming the average of the 10 data values ​​is 1.04V. The composite high voltage value and the composite low voltage value are combined to form the actual depth of use range of the first nickel-metal hydride battery cell 5, such as 1.04V to 1.44V.

[0053] The actual operating depth range is compared with the preset standard operating range (set according to the performance parameters of the NiMH battery, such as 1.0V-1.45V) to calculate the degree of overlap between the two ranges. 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, if the actual range of 1.04V-1.44V overlaps the standard range of 1.0V-1.45V, the overlap is 1.04V-1.44V, 0.4V in length, and the total length of the standard range is 0.45V, then the overlap value is 0.4 / 0.45≈0.89.

[0054] The second cycle is positively correlated with the range overlap value. When the overlap value is high (such as 0.89 above), it indicates that the usage status of the NiMH battery deviates slightly from the standard status. In this case, the second cycle is appropriately extended, for example, from the original 2 hours to 3 hours, to reduce unnecessary capacity monitoring frequency and reduce system operating load and energy consumption. When the overlap value is low, such as the actual usage range is 0.95V~1.3V, and the overlap value with the standard range is only 0.5, it indicates that the battery usage status deviates from the standard and there may be a risk of overcharge or over-discharge. In this case, the second cycle is shortened, for example, from 2 hours to 1 hour. Through high-frequency monitoring, capacity changes are captured in a timely manner, so that the charging voltage or the number of parallel connections can be quickly adjusted to ensure the stable operation of the NiMH battery.

[0055] In the composite battery control method of the present application, a hierarchical adjustment and repair strategy may be adopted for the capacity balancing management of the first lithium battery cell 3 and the second lithium battery cell 4. The specific method includes the following steps: Regularly measure the real-time capacity of the first lithium battery cell 3 (i.e., the first capacity; for example, a certain measurement indicates 2800mAh) and the real-time capacity of the second lithium battery cell 4 (i.e., the second capacity; for example, a certain measurement indicates 2600mAh), and calculate the capacity difference between the two (e.g., 2800mAh - 2600mAh = 200mAh). Subsequently, based on a preset reference difference and the nominal capacity variation range of the lithium battery cells (e.g., 300mAh), the capacity unevenness is calculated using the formula "capacity unevenness = capacity unevenness / reference unevenness" (e.g., 200mAh / 300mAh ≈ 0.67).

[0056] If the calculated capacity unevenness is less than a preset reference unevenness, such as a reference unevenness of 0.8, the discharge voltage is adjusted according to the inverse correlation principle: the greater the capacity unevenness, that is, the closer the capacity difference between the two batteries is to the reference difference, the greater the adjustment of the discharge voltage. For example, when the unevenness is 0.67, the discharge voltage of the first lithium battery cell 3 with a higher capacity can be appropriately reduced by 0.1V, while the discharge voltage of the second lithium battery cell 4 with a lower capacity can be appropriately increased by 0.1V. This voltage compensation balances the output performance of the two batteries, preventing over-discharge of the higher-capacity battery and under-discharge of the lower-capacity battery.

[0057] If the capacity unevenness exceeds a preset reference unevenness, for example, if the first capacity is 3000mAh and the second capacity is 2400mAh, with a capacity difference of 600mAh, and the unevenness = 600 / 300 = 2.0>0.8, an emergency repair mechanism is triggered: the system first disconnects the first nickel-metal hydride battery cell 5 from the working circuit through circuit switching to prevent it from participating in charging and discharging when the lithium battery capacity is severely unbalanced, thereby exacerbating losses; then the battery balancing repair program is initiated, and the two lithium battery cells are replenished or discharged through a dedicated balancing circuit, such as replenishing the second lithium battery cell 4 to 2800mAh or discharging the first lithium battery cell 3 to 2800mAh, until the capacity difference between the two falls within the reference difference range, such as ≤300mAh.

[0058] Through the grading strategy, the system can maintain stable operation through refined voltage regulation when the capacity difference is small, preventing small differences from gradually accumulating into big problems. When the difference exceeds the standard, the auxiliary battery can be cut off in time and repair can be started, avoiding the risks of accelerated plate aging and increased capacity decay caused by long-term unbalanced operation of the two lithium batteries, effectively extending the overall service life of the lithium battery pack.

[0059] In the composite battery structure design of the present application, a targeted optimization scheme is adopted for the first nickel-hydrogen battery cell 5 and the overall safety protection. The specific implementation is as follows: The first nickel-metal hydride battery cell 5 adopts a liquid electrolyte structure, and its electrolyte is proportionally filled with 5% of a penetrant, such as a specific type of surfactant. It can significantly improve the wettability and ion conductivity of the electrolyte; the penetrant can reduce the interfacial tension between the electrolyte and the electrode material, allowing the electrolyte to more evenly cover the electrode surface, while promoting the migration efficiency of ions between the electrode and the electrolyte. In practical applications, this structure can increase the charge and discharge response speed of the nickel-metal hydride battery by about 10%-15%. For example, in discharge scenarios that require rapid voltage replenishment, the voltage regulation response time can be shortened, ensuring smoother coordination with the lithium battery and avoiding voltage fluctuations caused by the delayed response of the nickel-metal hydride battery.

[0060] The composite battery's housing is filled with a thermally conductive fluid 2, such as silicone oil or specialized battery coolant, ideally sufficient to completely soak the surface of each cell. Through convection and conduction, the thermally conductive fluid 2 quickly transfers heat generated by the first lithium-ion battery cell 3, the second lithium-ion battery cell 4, and the first nickel-metal hydride battery cell 5 to the entire housing, preventing localized heat accumulation. For example, when a lithium-ion battery generates significant heat due to high-rate discharge, the thermally conductive fluid 2 diffuses the heat from the battery surface to the housing's heat dissipation surface, reducing the local temperature by 5-8°C and effectively mitigating the effects of high temperatures on battery performance.

[0061] The battery casing 1 also features an explosion-proof hole 6 at the top, located in the center of the battery's internal cell arrangement. The hole's diameter is designed based on the casing's volume and a preset safety pressure, such as 3-5mm in diameter. The hole is covered with a thin aluminum seal (0.1-0.2mm thick). When an abnormal reaction within the battery (such as the initial stages of thermal runaway in a lithium battery) causes the pressure to rise to a preset threshold (e.g., 0.3MPa), the seal is breached by the pressure, rapidly releasing internal gas through the explosion-proof hole 6. This reduces the casing's internal pressure to a safe level within 1-2 seconds, preventing the casing from rupturing due to excessive pressure and structurally preventing the risk of explosion.

[0062] Through the above design, the performance synergy of the nickel-hydrogen battery is improved through electrolyte optimization, and a dual safety protection system is constructed with the help of the thermal conductive fluid 2 and the explosion-proof hole 6. While ensuring the working efficiency of the composite battery, the safety and reliability of the system are greatly improved.

[0063] An embodiment of the present application further discloses a composite battery control system for multiple types of single cells, including a processor, wherein the processor executes the steps of any one of the above-mentioned composite battery control methods for multiple types of single cells.

[0064] The embodiment of the present application further discloses a storage medium, wherein a program is stored in the storage medium. When the program is executed by a processor, the steps of any one of the above-mentioned methods for controlling a composite battery of multiple types of single cells are implemented.

[0065] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A composite battery control method for multiple types of single cells, characterized in that: The steps include: Based on the arrangement of a first lithium battery cell (3), a second lithium battery cell (4) and a first nickel-hydrogen battery cell (5); Obtaining a first voltage of a first lithium battery cell (3), a second voltage of a second lithium battery cell (4), and a third voltage of a first nickel-metal hydride battery cell (5); Calculate the sum of the first voltage and the second voltage as the lithium battery voltage sum; Based on the acquired charging instruction, the first lithium battery cell (3) and the second lithium battery cell (4) are connected in series and then charged; if the sum of the lithium battery voltages is greater than a 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-metal hydride battery cell (5) and then charged; Based on the obtained discharge instruction, the first lithium battery cell (3) and the second lithium battery cell (4) are connected in series and then discharged; If the lithium battery voltage sum is less than a preset discharge 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) and then discharged.

2. The composite battery control method of multiple types of single cells according to claim 1, characterized in that: The first lithium battery cell (3), the second lithium battery cell (4) and the first nickel-hydrogen battery cell (5) are arranged 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).

3. The composite battery control method of multiple types of single cells according to claim 2, characterized in that: The method also includes: In a set first cycle, 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 to obtain the lithium battery capacity; The discharge voltage value is adjusted inversely according to the capacity of the lithium battery. The larger the capacity of the lithium battery, the smaller the discharge voltage value; the smaller the capacity of the lithium battery, the larger the discharge voltage value.

4. The composite battery control method of multiple types of single cells according to claim 2, characterized in that: The method also includes: Calculating the capacity of the first nickel-hydrogen battery cell (5) according to the set second cycle as the nickel-hydrogen battery capacity; The preset charging voltage value is adjusted inversely according to the capacity of the nickel-hydrogen battery; the larger the capacity of the nickel-hydrogen battery, the smaller the preset charging voltage value; the smaller the capacity of the nickel-hydrogen battery, the larger the preset charging voltage value; Alternatively, the number of nickel-hydrogen batteries connected in parallel with the first nickel-hydrogen battery cell (5) is adjusted according to the positive correlation of the nickel-hydrogen battery capacity; the smaller the nickel-hydrogen battery capacity, the more nickel-hydrogen batteries connected in parallel; the larger the nickel-hydrogen battery capacity, the fewer nickel-hydrogen batteries connected in parallel.

5. The composite battery control method of multiple types of single cells according to claim 3, characterized in that: The method also includes: Obtaining energy usage speed and usage temperature of the first lithium battery cell (3) and the second lithium battery cell (4); The operating condition evaluation value is calculated based on the energy usage rate and operating temperature. The operating condition evaluation value = ω1×(vt / v_max)+ω2×(Tt / T_max); where: vt is the current energy usage rate, v_max is the preset maximum energy usage rate; Tt is the current operating temperature, and T_max is the preset maximum allowable operating temperature; ω1 and ω2 are the weight coefficients of energy usage rate and operating temperature, respectively, and ω1+ω2=1; (vt / v_max) and (Tt / T_max) are normalization processing items, with a value range of 0~1; The first period is adjusted inversely according to the operating condition evaluation value; the larger the operating condition evaluation value is, the shorter the corresponding first period is; the smaller the operating condition evaluation value is, the longer the corresponding first period is.

6. The composite battery control method of multiple types of single cells according to claim 4, characterized in that: Recording the starting voltage values ​​of the plurality of first nickel-hydrogen battery cells (5) after charging is completed; Recording the end-of-use voltage values ​​of a plurality of first nickel-hydrogen battery cells (5) at the start of charging; A comprehensive high voltage value is calculated based on multiple starting voltage values; A comprehensive low voltage value is calculated based on multiple end-of-use voltage values; The use depth range is obtained according to the combination of the comprehensive high voltage value and the comprehensive low voltage value; Calculate the degree of overlap between the use depth range and the preset standard use range; The second period is positively adjusted according to the range overlap value. The higher the range overlap value is, the longer the second period is; the lower the range overlap value is, the shorter the second period is.

7. The composite battery control method of multiple types of single cells according to claim 3, characterized in that: detecting that the capacity of the first lithium battery cell (3) is a first capacity and detecting that the capacity of the second lithium battery cell (4) is a second capacity; calculating a capacity difference based on the first capacity and the second capacity; The capacity unevenness is calculated based on the capacity difference and the preset reference difference; If the capacity unevenness is less than a preset reference unevenness, the discharge voltage value is adjusted inversely according to the capacity unevenness; Otherwise, the first nickel-hydrogen battery cell (5) is cut out of the circuit and battery balancing repair is performed on the first lithium battery cell (3) and the second lithium battery cell (4).

8. The composite battery control method of multiple types of single cells according to claim 2, characterized in that: The first nickel-hydrogen battery cell (5) adopts a liquid electrolyte structure, and the liquid electrolyte structure is filled with 5% of a penetrant; the composite battery also includes a heat-conducting liquid (2) for enhancing heat conduction between battery cells and an explosion-proof hole (6) provided on the battery housing (1) and capable of releasing pressure when the internal pressure exceeds a limit.

9. A composite battery control system for multiple types of single cells, characterized in that: The method comprises a processor, wherein the processor executes the steps of the composite battery control method for multiple types of single cells according to any one of claims 1 to 8.

10. A storage medium, characterized in that: The storage medium stores a program, and when the program is executed by the processor, the steps of the composite battery control method of multiple types of single cells according to any one of claims 1 to 8 are implemented.

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