Maintenance charging method, system and device for alternating current charging pile

Abstract

The invention discloses a maintenance charging method of an alternating current charging pile, which comprises the following steps: receiving battery information and charging mode information, the battery information comprises battery capacity, and the charging mode information comprises conventional charging mode information and maintenance charging mode information; when the maintenance charging mode information is received, selecting a conventional charging mode to execute charging, and when the maintenance charging mode information is received, selecting a maintenance charging mode to execute charging; after the maintenance charging mode is selected to execute charging, corresponding maintenance charging strategies are selected according to the battery capacity, and the number of the maintenance charging strategies is at least three, and the maintenance charging strategies correspond to different battery capacities respectively. Compared with the prior art, the maintenance function of the alternating current charging pile can be achieved.

Description

Technical Field

[0001] This invention relates to the field of charging technology, and in particular to a maintenance and charging method, system and device for AC charging piles. Background Technology

[0002] AC charging piles, as a core energy replenishment device in home scenarios, have gradually replaced traditional emergency energy replenishment methods and become the main choice for home charging due to their advantages such as convenient installation, low operating costs, and wide compatibility. However, as the service life of new energy vehicles increases, the voltage balance of individual cells in the power battery, as the core energy storage component of the vehicle, gradually becomes unbalanced due to factors such as the number of charge-discharge cycles, fluctuations in the operating environment temperature, and differences in aging rates. This imbalance directly leads to a significant decrease in the overall charging and discharging efficiency of the battery pack, resulting in a significant reduction in the vehicle's driving range. This not only seriously affects the user's daily driving experience but also shortens the overall lifespan of the power battery, increasing the user's later operating costs.

[0003] Currently, the industry's solutions to battery voltage equalization issues still primarily rely on battery management systems (BMS) developed by automakers themselves. However, existing BMS systems generally lack effective active equalization control methods, and due to the market's priority on rapid charging, most manufacturers focus on improving charging speed to meet users' immediate charging needs when formulating battery management strategies, while neglecting sufficient attention to the long-term maintenance of individual cell voltage equalization. This makes it difficult to fundamentally improve the equalization problem.

[0004] In view of this, a maintenance and charging method, system and device for AC charging piles are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a maintenance and charging method, system, and device for AC charging piles, so as to realize the maintenance function of AC charging piles.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A maintenance and charging method for an AC charging station, comprising the following steps: Receive battery information and charging mode information, wherein the battery information includes battery capacity, and the charging mode information includes regular charging mode information and maintenance charging mode information. When a normal charging mode message is received, select the normal charging mode to perform charging; when a maintenance charging mode message is received, select the maintenance charging mode to perform charging. After selecting the maintenance charging mode to perform charging, a corresponding maintenance charging strategy is selected according to the battery capacity. The maintenance charging strategy includes at least three strategies, each corresponding to a different battery capacity.

[0007] In a preferred embodiment, the maintenance charging strategy includes a low-capacity charging strategy, a medium-capacity charging strategy, and a high-capacity charging strategy. The power curve function under the low-capacity charging strategy is denoted as f1(x), the power curve function under the medium-capacity charging strategy is denoted as f2(x), and the power curve function under the high-capacity charging strategy is denoted as f3(x). The battery capacity is parameter a, and the first capacity node is denoted as j, the second capacity node as h, and the third capacity node as k. The following function is available:

[0008] Where a is a positive number, u is the input voltage, and t is the charging time.

[0009] In a preferred embodiment, the first capacity node j is 40, the second capacity node h is 60, and the third capacity node k is 100.

[0010] In a preferred embodiment, the charging time t ≤ 24.

[0011] In a preferred embodiment, the battery capacity is the full capacity of the battery.

[0012] In a preferred embodiment, the maintenance charging mode is selected to perform charging only when the battery level is between 15% and 25%.

[0013] In a preferred embodiment, the battery capacity is calculated as follows: Get the battery's full capacity and currently used capacity; Calculate remaining capacity: Total capacity - Used capacity; Calculate battery capacity = remaining capacity / (100% - preset remaining charge during maintenance).

[0014] In a preferred embodiment, the maintenance preset remaining battery power is set to 15%-25%.

[0015] A maintenance charging system for an AC charging station, comprising: An information receiving unit is used to receive battery information and charging mode information. The battery information includes battery capacity, and the charging mode information includes regular charging mode information and maintenance charging mode information. The mode selection unit is used to select the normal charging mode to perform charging when receiving normal charging mode information, and to select the maintenance charging mode to perform charging when receiving maintenance charging mode information. The maintenance charging unit is used to select a corresponding maintenance charging strategy based on the battery capacity after selecting the maintenance charging mode to perform charging. The maintenance charging strategy includes at least three strategies, each corresponding to a different battery capacity.

[0016] The maintenance charging strategy includes a low-capacity charging strategy, a medium-capacity charging strategy, and a high-capacity charging strategy. The power curve function under the low-capacity charging strategy is denoted as f1(x), the power curve function under the medium-capacity charging strategy is denoted as f2(x), and the power curve function under the high-capacity charging strategy is denoted as f3(x). The battery capacity is parameter a, and the first capacity node is j, the second capacity node is h, and the third capacity node is k. The following function is given:

[0017] Where a is a positive number, u is the input voltage, and t is the charging time.

[0018] A maintenance and charging device for an AC charging pile, which applies the maintenance and charging method for the AC charging pile, or applies the maintenance and charging system for the AC charging pile.

[0019] Compared with the prior art, the present invention has the following beneficial effects: Within the technical framework of its defined AC charging pile maintenance charging method, this method first achieves a core functional upgrade of AC charging piles from traditional "passive response" to "active control," completely eliminating the complete dependence of existing charging technologies on the vehicle's Battery Management System (BMS). This effectively solves the key flaw in existing technologies where the vehicle's BMS prioritizes rapid energy replenishment while neglecting battery cell voltage balancing. Specifically, this method receives user-input battery information (core information includes battery capacity) and charging mode information (distinguishing between regular charging and maintenance charging). It can then activate dedicated control logic in maintenance charging mode, rather than passively executing vehicle BMS commands as a mere energy transmission channel, as is the case with conventional charging piles. This gives the charging pile the ability to independently formulate battery maintenance strategies. Even if the vehicle's BMS's own balancing logic is imperfect or has a low priority, the charging pile can still actively intervene to achieve efficient battery balancing management.

[0020] Furthermore, the solution explicitly states that "a corresponding maintenance and charging strategy is selected based on the battery capacity, and at least three maintenance and charging strategies are required." This design can accurately adapt to new energy vehicle batteries of different capacity specifications on the market (covering more than 95% of common models), avoiding the problem of poor balancing effect caused by the inability of existing general-purpose charging strategies to match the characteristics of batteries with different capacities. For example, for small-capacity batteries, the corresponding maintenance and charging strategy can be adjusted to a relatively low-power mode to avoid charging too quickly and affecting balancing; for large-capacity batteries, an optimized power curve can ensure that the charging process from 20% to 100% SOC is completed within 24 hours, while providing sufficient time for battery cell balancing. This differentiated strategy design based on battery capacity allows each type of battery to obtain an appropriate charging current (precise control within the range of 8-32A) and power output, ensuring that the battery management system has sufficient time to execute the cell voltage balancing algorithm during the charging process, gradually reducing the voltage difference between individual cells and avoiding battery capacity degradation caused by the accumulation of voltage differences.

[0021] Ultimately, this method, through proactively developing maintenance strategies and differentiated capacity adaptation, directly promotes the uniformity of individual cell voltages in battery cells, effectively improving battery capacity saturation. Compared to traditional charging methods that rely on the vehicle's BMS, this method allows the battery to store more energy at the same SOC state, resulting in a significant improvement in vehicle range. Furthermore, consistent maintenance charging over the long term can slow down battery capacity degradation, indirectly extending the overall battery lifespan. This provides users with the dual benefits of "improved range + battery durability," and also gives AC charging stations added-value battery maintenance functions beyond basic charging. Attached Figure Description

[0022] Figure 1 This invention relates to a flowchart of a maintenance and charging method for an AC charging pile.

[0023] Figure 2 This invention relates to a power curve diagram of a low-capacity charging strategy for the maintenance charging method of an AC charging pile.

[0024] Figure 3 This invention relates to a power curve diagram of a medium-capacity charging strategy for the maintenance and charging method of an AC charging pile.

[0025] Figure 4 This invention relates to a power curve diagram of a high-capacity charging strategy for the maintenance and charging method of an AC charging pile. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings.

[0027] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention. Example 1:

[0028] like Figure 1 As shown, a maintenance and charging method for an AC charging station includes the following steps: Receive battery information and charging mode information, wherein the battery information includes battery capacity, and the charging mode information includes regular charging mode information and maintenance charging mode information: When a normal charging mode message is received, select the normal charging mode to perform charging; when a maintenance charging mode message is received, select the maintenance charging mode to perform charging. After selecting the maintenance charging mode to perform charging, a corresponding maintenance charging strategy is selected according to the battery capacity. The maintenance charging strategy includes at least three strategies, each corresponding to a different battery capacity.

[0029] In the technical architecture of AC charging pile maintenance and charging methods, the primary achievement is a fundamental transformation of the AC charging pile's function—from a single role of "passively receiving vehicle commands and only undertaking power transmission" in traditional charging scenarios, to a core control role of "actively leading the charging process and independently formulating maintenance plans." This transformation completely breaks through the technical limitations of existing charging technologies that rely entirely on the vehicle's Battery Management System (BMS), effectively solving the key problem in existing solutions where the vehicle's BMS prioritizes "rapid energy replenishment," thus weakening battery cell voltage balancing. Even if some vehicles' BMS balancing logic has design flaws or low priority settings, this method allows the AC charging pile to still provide efficient battery balancing management through its own strategy formulation capabilities, without being constrained by the vehicle's control logic.

[0030] Meanwhile, the design, which selects corresponding maintenance and charging strategies based on battery capacity, with at least three maintenance and charging strategies, boasts strong adaptability. It can accurately cover the vast majority of new energy vehicle batteries on the market (covering over 95% of common models), avoiding the problems of existing universal charging strategies failing to match the charging and discharging characteristics of batteries with different capacities. This results in small-capacity batteries charging too quickly and having insufficient balancing time, or large-capacity batteries taking too long and being inefficient. For example, for small-capacity batteries, the corresponding maintenance and charging strategy uses a relatively gentle power output and appropriate current (precisely controlled within the range of 8-32A) to ensure sufficient balancing. For large-capacity batteries, an optimized power curve design efficiently completes a 20%-100% SOC charging cycle within 24 hours, while reserving sufficient time for battery cell balancing. This differentiated strategy based on battery capacity allows each type of battery to operate under suitable charging conditions, ensuring the battery management system has sufficient time to execute the cell voltage balancing algorithm, gradually reducing the voltage difference between individual cells and preventing battery capacity degradation caused by long-term accumulation of voltage differences.

[0031] The above methods, through the dual effects of active control and differentiated adaptation, promote the stable and consistent voltage of individual battery cells, significantly improving battery capacity. Compared to traditional charging methods that rely on the vehicle's BMS, this method allows the battery to store more energy at the same SOC state, directly resulting in an increased vehicle range. Long-term use also slows down battery capacity degradation, extending the overall battery lifespan. This not only brings users the practical benefits of "enhanced range and more durable batteries," but also allows AC charging piles to transcend the basic charging function boundaries, adding value-added attributes such as battery maintenance. Furthermore, the maintenance charging strategy includes low-capacity charging, medium-capacity charging, and high-capacity charging strategies. The power curve function under the low-capacity charging strategy is denoted as f1(x), the power curve function under the medium-capacity charging strategy is denoted as f2(x), and the power curve function under the high-capacity charging strategy is denoted as f3(x). The battery capacity is parameter a, and the first capacity node is j, the second capacity node is h, and the third capacity node is k, with the following function:

[0032] Where a is a positive number, u is the input voltage, and t is the charging time. In this embodiment, u is 220V.

[0033] The battery charging strategies are divided into three categories—low, medium, and high—based on capacity, and differentiated power curves are designed accordingly. This perfectly matches the charging and discharging characteristics and maintenance needs of batteries with different capacities, solving the problems of poor adaptability and unstable balancing effects caused by the "one-size-fits-all" approach of traditional general strategies. The low-capacity charging strategy adopts a horizontal power curve corresponding to the minimum current. Its core advantage lies in adapting to the characteristics of low-capacity batteries, such as weak charging acceptance and relatively limited heat dissipation performance. The minimum current output can always maintain a stable charging state, avoiding uneven local heating or increased cell voltage differences caused by current fluctuations. At the same time, the continuous and constant low-power environment allows the battery management system (BMS) to fully execute the cell voltage balancing algorithm in a stable scenario unaffected by power changes, ensuring a smooth and thorough balancing process without being interrupted by sudden increases or decreases in current, thus maximizing the balancing effect.

[0034] The medium-capacity charging strategy, designed with a curve of "charging at maximum power first, then gradually reducing power, and finally ending at the lowest power," precisely balances maintenance efficiency and equalization depth. Initially, maximum power is used to quickly increase the battery's SOC from 20% to the mid-to-high range, effectively shortening the overall maintenance cycle and preventing users from being discouraged from using the battery due to excessive charging time. As the SOC increases, the battery's charging acceptance gradually decreases. Gradually reducing power at this point reduces battery heat generation, prevents cell damage due to overcurrent, and allows more time to address voltage differences between cells. Finally, switching to the lowest power, through slow charging at extremely low power, finely balances the remaining voltage differences, further reducing the voltage gap between cells.

[0035] The high-capacity charging strategy, designed to be "similar to the medium-capacity strategy but with a slower power decay rate," fully considers the characteristics of high-capacity batteries—large energy reserves and the need for more energy replenishment. The slower power decay rate maintains a relatively high charging power for a longer period, ensuring smooth energy replenishment of high-capacity batteries within the maintenance cycle and preventing charging timeouts due to rapid power decay. Simultaneously, the slowly decreasing power curve avoids significant fluctuations, providing a continuous and stable balancing environment while simultaneously promoting cell voltage balancing during the replenishment of large amounts of energy. This prevents situations where "replenishment is completed but balancing is insufficient," achieving the dual goals of "efficient replenishment" and "deep balancing." Overall, the three types of curves are precisely designed for the characteristics of batteries with different capacities, allowing each type of battery to complete maintenance under suitable charging conditions. This ensures charging safety and efficiency while maximizing cell voltage balancing.

[0036] Furthermore, the first capacity node j is 40, the second capacity node h is 60, and the third capacity node k is 100. These three nodes accurately cover the battery capacities of most new energy vehicles on the market, allowing charging piles to quickly and mismatch-freely match strategies without manual intervention. This avoids overheating caused by using high-power strategies for low-capacity batteries or charging timeouts caused by using low-power strategies for high-capacity batteries due to ambiguous capacity ranges, and also allows each type of battery to achieve deep balance under the most suitable curve.

[0037] In this embodiment, the charging time t≤24, so that the maintenance time is controlled within 24 hours.

[0038] In this embodiment, for medium and high capacity states, the decrease in charging power in the middle section is beneficial for the battery to be charged more fully. This rate of decrease is adopted to meet the requirement of completing charging within 24 hours, so as not to be too slow.

[0039] In this embodiment, the battery capacity refers to the total capacity of the battery, that is, the actual total capacity of the battery. For example, if the vehicle battery is 100 kWh, then its battery capacity is 100 kWh.

[0040] Furthermore, the maintenance charging mode is only selected when the battery level is between 15% and 25%, with 20% being the preferred setting. Limiting the starting charge level for the maintenance charging mode to 15%-25% (preferably 20%) ensures that maintenance conditions are met. Compared to non-low-level starting, the cell balancing effect is more significant, further guaranteeing the fullness of battery capacity.

[0041] In this embodiment, the power curves for the low-capacity charging strategy, the medium-capacity charging strategy, and the high-capacity charging strategy are shown in the figure below. Figures 2 to 4 As shown, Figures 2 to 4 In the graph, the vertical axis represents power in kilowatts, and the horizontal axis represents time in hours. Example 2:

[0042] like Figure 1 As shown, a maintenance and charging method for an AC charging station includes the following steps: Receive battery information and charging mode information, wherein the battery information includes battery capacity, and the charging mode information includes regular charging mode information and maintenance charging mode information. When a normal charging mode message is received, select the normal charging mode to perform charging; when a maintenance charging mode message is received, select the maintenance charging mode to perform charging. After selecting the maintenance charging mode to perform charging, a corresponding maintenance charging strategy is selected according to the battery capacity. The maintenance charging strategy includes at least three strategies, each corresponding to a different battery capacity.

[0043] In the technical architecture of AC charging pile maintenance and charging methods, the primary achievement is a fundamental transformation of the AC charging pile's function—from a single role of "passively receiving vehicle commands and only undertaking power transmission" in traditional charging scenarios, to a core control role of "actively leading the charging process and independently formulating maintenance plans." This transformation completely breaks through the technical limitations of existing charging technologies that rely entirely on the vehicle's Battery Management System (BMS), effectively solving the key problem in existing solutions where the vehicle's BMS prioritizes "rapid energy replenishment," thus weakening battery cell voltage balancing. Even if some vehicles' BMS balancing logic has design flaws or low priority settings, this method allows the AC charging pile to still provide efficient battery balancing management through its own strategy formulation capabilities, without being constrained by the vehicle's control logic.

[0044] Meanwhile, the design, which selects corresponding maintenance and charging strategies based on battery capacity, with at least three maintenance and charging strategies, boasts strong adaptability. It can accurately cover the vast majority of new energy vehicle batteries on the market (covering over 95% of common models), avoiding the problems of existing universal charging strategies failing to match the charging and discharging characteristics of batteries with different capacities. This results in small-capacity batteries charging too quickly and having insufficient balancing time, or large-capacity batteries taking too long and being inefficient. For example, for small-capacity batteries, the corresponding maintenance and charging strategy uses a relatively gentle power output and appropriate current (precisely controlled within the range of 8-32A) to ensure sufficient balancing. For large-capacity batteries, an optimized power curve design efficiently completes a 20%-100% SOC charging cycle within 24 hours, while reserving sufficient time for battery cell balancing. This differentiated strategy based on battery capacity allows each type of battery to operate under suitable charging conditions, ensuring the battery management system has sufficient time to execute the cell voltage balancing algorithm, gradually reducing the voltage difference between individual cells and preventing battery capacity degradation caused by long-term accumulation of voltage differences.

[0045] The above methods, through the dual effects of active control and differentiated adaptation, promote a more stable and consistent voltage across individual battery cells, significantly improving battery capacity. Compared to traditional charging methods that rely on the vehicle's BMS, this method allows the battery to store more energy at the same SOC, directly resulting in increased vehicle range. Long-term use also slows down battery capacity degradation, extending the overall battery lifespan. This not only brings users tangible benefits of enhanced range and longer battery life but also allows AC charging stations to transcend the basic charging function, adding value through battery maintenance.

[0046] In a preferred embodiment, the maintenance charging strategy includes a low-capacity charging strategy, a medium-capacity charging strategy, and a high-capacity charging strategy. The power curve function under the low-capacity charging strategy is denoted as f1(x), the power curve function under the medium-capacity charging strategy is denoted as f2(x), and the power curve function under the high-capacity charging strategy is denoted as f3(x). The battery capacity is parameter a, and the first capacity node is denoted as j, the second capacity node as h, and the third capacity node as k. The following function is available: Where a is a positive number, u is the input voltage, and t is the charging time.

[0047] In the technical architecture of AC charging pile maintenance and charging methods, the primary achievement is a fundamental transformation of the AC charging pile's function—from a single role of "passively receiving vehicle commands and only undertaking power transmission" in traditional charging scenarios, to a core control role of "actively leading the charging process and independently formulating maintenance plans." This transformation completely breaks through the technical limitations of existing charging technologies that rely entirely on the vehicle's Battery Management System (BMS), effectively solving the key problem in existing solutions where the vehicle's BMS prioritizes "rapid energy replenishment," thus weakening battery cell voltage balancing. Even if some vehicles' BMS balancing logic has design flaws or low priority settings, this method allows the AC charging pile to still provide efficient battery balancing management through its own strategy formulation capabilities, without being constrained by the vehicle's control logic.

[0048] Meanwhile, the design, which selects corresponding maintenance and charging strategies based on battery capacity, with at least three maintenance and charging strategies, boasts strong adaptability. It can accurately cover the vast majority of new energy vehicle batteries on the market (covering over 95% of common models), avoiding the problems of existing universal charging strategies failing to match the charging and discharging characteristics of batteries with different capacities. This results in small-capacity batteries charging too quickly and having insufficient balancing time, or large-capacity batteries taking too long and being inefficient. For example, for small-capacity batteries, the corresponding maintenance and charging strategy uses a relatively gentle power output and appropriate current (precisely controlled within the range of 8-32A) to ensure sufficient balancing. For large-capacity batteries, an optimized power curve design efficiently completes a 20%-100% SOC charging cycle within 24 hours, while reserving sufficient time for battery cell balancing. This differentiated strategy based on battery capacity allows each type of battery to operate under suitable charging conditions, ensuring the battery management system has sufficient time to execute the cell voltage balancing algorithm, gradually reducing the voltage difference between individual cells and preventing battery capacity degradation caused by long-term accumulation of voltage differences.

[0049] The above methods, through the dual effects of active control and differentiated adaptation, promote a more stable and consistent voltage across individual battery cells, significantly improving battery capacity. Compared to traditional charging methods that rely on the vehicle's BMS, this method allows the battery to store more energy at the same SOC, directly resulting in increased vehicle range. Long-term use also slows down battery capacity degradation, extending the overall battery lifespan. This not only brings users tangible benefits of enhanced range and longer battery life but also allows AC charging stations to transcend the basic charging function, adding value through battery maintenance.

[0050] Furthermore, the first capacity node j is 40, the second capacity node h is 60, and the third capacity node k is 100. These three nodes accurately cover the battery capacities of most new energy vehicles on the market, allowing charging piles to quickly and mismatch-freely match strategies without manual intervention. This avoids overheating caused by using high-power strategies for low-capacity batteries or charging timeouts caused by using low-power strategies for high-capacity batteries due to ambiguous capacity ranges, and also allows each type of battery to achieve deep balance under the most suitable curve.

[0051] In this embodiment, the charging time t≤24, so that the maintenance time is controlled within 24 hours.

[0052] In this embodiment, the battery capacity is not the actual size of the battery; the battery capacity is calculated as follows: Get the battery's full capacity and currently used capacity; Calculate remaining capacity: Total capacity - Used capacity; Calculate battery capacity = remaining capacity / (100% - preset remaining charge during maintenance).

[0053] The core technical principle of the above battery capacity calculation method is based on the "effective charging range" of maintenance charging (i.e., from the preset remaining charge (e.g., 20%) to 100% SOC). By using the actual remaining capacity of the current battery, the "equivalent calculated capacity" that fits this range is derived. In the formula "Battery capacity = Remaining capacity ÷ (100% - Preset remaining charge for maintenance)", "100% - Preset remaining charge for maintenance" is essentially the percentage of the SOC range that the maintenance needs to cover (e.g., 80%). Through this percentage, the "actual remaining capacity" (corresponding to the charge from the current SOC to 100%) is converted into the "equivalent calculated capacity" (corresponding to the complete ideal range of charge from 20% to 100%), so that the charging pile can match the corresponding maintenance strategy based on the equivalent capacity.

[0054] Its design aims to address the core pain point of users struggling to precisely control the battery level at the ideal 20% maintenance starting point in actual operation. Users often activate maintenance mode with a battery level higher than 20% (such as 35% or 55%) due to factors such as travel arrangements and charging habits. If the strategy is directly matched according to the actual battery capacity, the "effective charging range is compressed" (e.g., from 35% to 100% only covers 65% SOC instead of the ideal 80%), leading to strategy mismatch (e.g., using a large capacity strategy but only needing to add a small amount of power, resulting in insufficient balancing time). However, this calculation method can transform the "remaining capacity at a non-ideal starting point" into the "equivalent capacity at an ideal starting point," ensuring that the core basis for strategy matching changes from the "actual physical capacity of the battery" to the "scale of power required for maintenance." This eliminates the need for users to adjust the battery level while guaranteeing maintenance effectiveness and efficiency.

[0055] A concrete example further illustrates its value: Assume the battery's actual capacity is 100 kWh, and the preset remaining charge for maintenance is 20%. When the user initiates maintenance at 35% charge, the remaining capacity is "100 kWh - (100 kWh × 35%) = 65 kWh" (meaning 65 kWh needs to be added to charge from 35% to 100%). Substituting this into the formula, we get "Battery capacity = 65 kWh ÷ (100% - 20%) = 81.25 kWh"—this 81.25 kWh equivalent capacity corresponds to the ideal scenario of "81.25 kWh × 80% = 65 kWh needing to be added to charge from 20% to 100%". Therefore, the charging station is equipped with a "large-capacity maintenance strategy" (adapted to the scale requiring 65 kWh of additional charge). Its "slow power decline rate" characteristic allows it to complete the 65 kWh charge replenishment within 21-24 hours, while simultaneously improving the battery management system (BMS). Sufficient time is provided to balance the cell voltage. When the user starts maintenance at 55% charge, the remaining capacity is "100 kWh - (100 kWh × 55%) = 45 kWh" (45 kWh needs to be added from 55% to 100%). The calculated "battery capacity = 45 kWh ÷ 80% = 56.25 kWh" corresponds to the ideal scenario of "56.25 kWh × 80% = 45 kWh needs to be added from 20% to 100%". At this time, the charging pile automatically switches to the "medium capacity maintenance strategy". Its design of "first charging at maximum power and then gradually reducing power" can efficiently add 45 kWh of power in 18-21 hours, which avoids the interruption of balancing due to excessive power and prevents the charging time from being extended due to excessively low power.

[0056] As can be seen, this design, through "equivalent capacity conversion," ensures that the matching of maintenance strategies always revolves around the "scale of electricity to be replenished." No matter how much the user's actual electricity deviates from 20%, it can accurately match the appropriate power curve, which not only completely reduces the user's operating threshold (no need to deliberately discharge to 20%), but also ensures that each maintenance can achieve cell voltage balance based on reasonable power output.

[0057] Specifically, in this embodiment, the preset remaining battery power for maintenance is set to 15%-25%, preferably 20%.

[0058] In this embodiment, the power curves for the low-capacity charging strategy, the medium-capacity charging strategy, and the high-capacity charging strategy are shown in the figure below. Figures 2 to 4 As shown, Figures 2 to 4 In the graph, the vertical axis represents power in kilowatts, and the horizontal axis represents time in hours. Example 3:

[0059] A maintenance charging system for an AC charging station, comprising: An information receiving unit is used to receive battery information and charging mode information. The battery information includes battery capacity, and the charging mode information includes regular charging mode information and maintenance charging mode information. The mode selection unit is used to select the normal charging mode to perform charging when receiving normal charging mode information, and to select the maintenance charging mode to perform charging when receiving maintenance charging mode information. The maintenance charging unit is used to select a corresponding maintenance charging strategy based on the battery capacity after selecting the maintenance charging mode to perform charging. The maintenance charging strategy includes at least three strategies, each corresponding to a different battery capacity.

[0060] The maintenance charging strategy includes a low-capacity charging strategy, a medium-capacity charging strategy, and a high-capacity charging strategy. The power curve function under the low-capacity charging strategy is denoted as f1(x), the power curve function under the medium-capacity charging strategy is denoted as f2(x), and the power curve function under the high-capacity charging strategy is denoted as f3(x). The battery capacity is parameter a, and the first capacity node is j, the second capacity node is h, and the third capacity node is k. The following function is given:

[0061] Where a is a positive number, u is the input voltage, and t is the charging time. Example 4:

[0062] A maintenance and charging device for an AC charging pile, which applies the maintenance and charging method for the AC charging pile or the maintenance and charging system for the AC charging pile.

[0063] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Unless otherwise specified, an element defined by the phrase "comprising..." or "including..." does not exclude the presence of additional elements in the process, method, article, or terminal device that includes said element. Additionally, in this document, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number.

[0064] In all the above embodiments, the unit of battery capacity is degrees.

[0065] The above description of the embodiments is provided to facilitate understanding and use of the present invention by those skilled in the art. It is obvious to those skilled in the art that various modifications can be easily made to the embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A maintenance and charging method for an AC charging pile, characterized in that, Including the following steps: Receive battery information and charging mode information, wherein the battery information includes battery capacity, and the charging mode information includes regular charging mode information and maintenance charging mode information. When a normal charging mode message is received, select the normal charging mode to perform charging; when a maintenance charging mode message is received, select the maintenance charging mode to perform charging. After selecting the maintenance charging mode to start charging, select the corresponding maintenance charging strategy according to the battery capacity. The maintenance charging strategy includes a low-capacity charging strategy, a medium-capacity charging strategy, and a high-capacity charging strategy. The power curve function under the low-capacity charging strategy is denoted as f1(x), the power curve function under the medium-capacity charging strategy is denoted as f2(x), and the power curve function under the high-capacity charging strategy is denoted as f3(x). The battery capacity is parameter a, and the first capacity node is j, the second capacity node is h, and the third capacity node is k. The following function is given: ； Where a is a positive number, u is the input voltage, and t is the charging time.

2. The maintenance and charging method for an AC charging pile according to claim 1, characterized in that, The first capacity node j is 40, the second capacity node h is 60, and the third capacity node k is 100.

3. The maintenance and charging method for an AC charging pile according to claim 1, characterized in that, The charging time t≤24.

4. The maintenance and charging method for an AC charging pile according to any one of claims 1 to 3, characterized in that, The battery capacity refers to the total capacity of the battery.

5. The maintenance and charging method for an AC charging pile according to claim 4, characterized in that, Only select the maintenance charging mode to start charging when the battery level is between 15% and 25%.

6. A maintenance and charging method for an AC charging pile according to any one of claims 1 to 3, characterized in that, The battery capacity is calculated as follows: Get the battery's full capacity and currently used capacity; Calculate remaining capacity: Total capacity - Used capacity; Calculate battery capacity = remaining capacity / (100% - preset remaining charge during maintenance).

7. The maintenance and charging method for an AC charging pile according to claim 6, characterized in that, The preset remaining battery level for maintenance is 15%-25%.

8. A maintenance charging system for an AC charging pile, characterized in that, include: An information receiving unit is used to receive battery information and charging mode information. The battery information includes battery capacity, and the charging mode information includes regular charging mode information and maintenance charging mode information. The mode selection unit is used to select the normal charging mode to perform charging when receiving normal charging mode information, and to select the maintenance charging mode to perform charging when receiving maintenance charging mode information. The maintenance charging unit is used to select the corresponding maintenance charging strategy based on the battery capacity after selecting the maintenance charging mode to perform charging. The maintenance charging strategy includes a low-capacity charging strategy, a medium-capacity charging strategy, and a high-capacity charging strategy. The power curve function under the low-capacity charging strategy is denoted as f1(x), the power curve function under the medium-capacity charging strategy is denoted as f2(x), and the power curve function under the high-capacity charging strategy is denoted as f3(x). The battery capacity is parameter a, and the first capacity node is j, the second capacity node is h, and the third capacity node is k. The following function is given: ； Where a is a positive number, u is the input voltage, and t is the charging time.

9. A maintenance charging device for an AC charging pile, characterized in that, The maintenance and charging method of the AC charging pile according to any one of claims 1 to 7, or the maintenance and charging system of the AC charging pile according to claim 8.

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