Multi-battery charging method and electronic product

Abstract

This invention discloses a multi-battery charging method and electronic product, comprising: formulating a battery charging curve based on the characteristics of the batteries, wherein the battery charging curve includes at least a high-current constant-current charging stage, an adjustment charging stage, a low-current constant-current charging stage, and a constant-voltage charging stage; controlling multiple batteries to sequentially enter and complete the high-current constant-current charging stage, then sequentially enter and complete the adjustment charging stage, then sequentially enter and complete the low-current constant-current charging stage, and finally sequentially enter the constant-voltage charging stage until charging is completed. This invention, by controlling multiple batteries to alternately enter the high-current fast charging stage, enables multiple batteries to rapidly increase their battery capacity in a very short time. Applying this method to electronic products equipped with multiple batteries allows the electronic product to obtain the maximum charging capacity within a limited time, achieving long battery life with short charging time, thus improving the user experience.

Description

Technical Field

[0001] This invention belongs to the field of battery charging technology, specifically, it relates to a charging control method based on multiple batteries. Background Technology

[0002] Head-mounted displays (HUDs) are video playback devices that magnify images on a micro-display screen using an optical system and project the images onto the user's retina, thus presenting a large-screen image to the user's eyes. They can achieve different display effects such as virtual reality (VR), augmented reality (AR), and mixed reality (MR). HUDs are popular among consumers due to their unique immersive experience and diverse application software. However, running these large applications consumes a significant amount of power, thus placing higher demands on battery life. Therefore, some HUDs are equipped with two batteries to increase battery capacity and improve overall battery life.

[0003] For batteries used in portable electronic products, it often takes a long time to fully charge from a low level, ranging from approximately 2 to 4 hours or even longer, depending on the battery capacity. A dual-battery design undoubtedly places higher demands on charging efficiency.

[0004] Current dual-battery charging technology still uses a conventional sequential charging method, that is, fully charging the main battery first, and then charging the secondary battery. Both the main and secondary batteries undergo multiple stages during the charging process, including constant current charging, constant voltage charging, and trickle charging. The constant current charging stage can increase the battery capacity to about 90% of its full capacity, and it only takes about half or less of the total charging time; the majority of the time is spent in the constant voltage charging and trickle charging stages. If the conventional charging sequence is followed, waiting until the main battery is fully charged before charging the secondary battery, the maximum amount of charge cannot be obtained within a limited time, resulting in lower charging efficiency and affecting the product's battery life. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-battery charging method to solve the problem that the conventional strategy of charging multiple batteries sequentially cannot obtain the maximum charging amount within a limited time.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: In one aspect, the present invention provides a multi-battery charging method, comprising: A battery charging curve is formulated based on the battery's own characteristics, and the battery charging curve includes at least a high current constant current charging stage, an adjustment charging stage, a low current constant current charging stage, and a constant voltage charging stage; wherein, the adjustment charging stage is a transition stage from the high current constant current charging stage to the low current constant current charging stage, and in the adjustment charging stage, the battery charging current decreases from the charging current of the high current constant current charging stage to the charging current of the low current constant current charging stage. Control multiple batteries to enter and complete the high-current constant-current charging stage in sequence; Control the multiple batteries to sequentially enter and complete the adjustment charging stage; Control the multiple batteries to sequentially enter and complete the low-current constant-current charging stage; The multiple batteries are controlled to enter the constant voltage charging stage sequentially until charging is completed.

[0007] In some embodiments of this application, in order to monitor whether the charging process of each battery in the high-current constant current charging stage has ended, the battery voltage value V1(i) to be reached by each battery in the high-current constant current charging stage can be determined first according to the battery charging curve of each battery, i=1,2,……,n, where n is the number of batteries; then, the first battery is controlled to enter the high-current constant current charging stage, and charging is paused when the battery voltage of the first battery reaches V1(1), and the second battery is switched to enter the high-current constant current charging stage until the battery voltage of the second battery reaches V1(2), and so on, until all batteries have completed the high-current constant current charging stage, and then the adjustment charging stage is entered.

[0008] In some embodiments of this application, in order to achieve fast charging, the charging current I1(i) of the high-current constant current charging stage can be configured to take a value between [0.9C, 1C); where C is the current value corresponding to the rated capacity of the battery; after the i-th battery enters the high-current constant current charging stage, the i-th battery is charged with constant current using the charging current I1(i) to quickly replenish the battery power in a high-current charging manner, thereby shortening the battery charging time.

[0009] In some embodiments of the present application, in order to solve the safety problems brought by the large charging current and long duration during the constant current charging stage of a large-capacity battery, the constant current charging stage of the present application is subdivided into a large current constant current charging stage and a small current constant current charging stage. In order to smoothly transition the charging current of the battery from the large current constant current charging stage to the small current constant current charging stage, during the adjustment charging stage, first, according to the battery charging curve of each battery, the charging current I2(i) of each battery during the small current constant current charging stage can be determined, where i = 1, 2, ……, n, and n is the number of batteries; then, after the ith battery enters the adjustment charging stage, when it is monitored that the difference between the charging current of the ith battery and I2(i) is less than the set threshold STEP_I, that is, when the charging current of the battery is very close to the charging current value during the small current constant current charging stage, the charging is paused, and the next battery is switched to enter the adjustment charging stage.

[0010] In some embodiments of the present application, in order to monitor whether the charging process of the battery during the adjustment charging stage is completed, after the ith battery enters the adjustment charging stage, the instantaneous charging current I of the ith battery can be read every T1 time; when the instantaneous charging current I < I2(i) + STEP_I, the instantaneous charging current of the ith battery is continuously read three times, and the interval time is T2, where T2 < T1, and thus three instantaneous charging current values I1, I2, and I3 can be obtained; then, the differences between the three instantaneous charging current values I1, I2, and I3 and I2(i) are calculated and the absolute values are taken, which are respectively denoted as △I1, △I2, and △I3; if at least one of △I1, △I2, and △I3 is greater than the set threshold STEP_I, it means that the charging current of the ith battery is not very close to the charging current value during the small current constant current charging stage. At this time, the instantaneous charging current of the ith battery can be continuously read three times again, and △I1, △I2, and △I3 are calculated until △I1, △I2, and △I3 are all less than the set threshold STEP_I, indicating that the charging current of the ith battery is already very close to the charging current value during the small current constant current charging stage. At this time, the charging process of the ith battery can be paused, and the next battery is switched to enter the adjustment charging stage.

[0011] In some embodiments of the present application, it is preferably configured that T1 = 5 s; T2 = 10 ms; the set threshold STEP_I can be taken between 10% and 20% of I2(i) to achieve an ideal monitoring effect.

[0012] In some embodiments of the present application, in order to achieve a smooth transition of the charging current, during the adjustment charging stage, the change curve of the charging current of the ith battery can be an oblique line starting from the charging current I1(i) during the large current constant current charging stage and ending at the charging current I2(i) during the small current constant current charging stage, realizing an equal decrease in the charging current.

[0013] In some embodiments of this application, in order to monitor whether the charging process of each battery in the low current constant current charging stage has ended, the battery voltage value V2(i) to be reached by each battery in the low current constant current charging stage can be determined first according to the battery charging curve of each battery, i=1,2,……,n, where n is the number of batteries; then, the first battery is controlled to enter the low current constant current charging stage, and charging is paused when the battery voltage of the first battery reaches V2(1), and the second battery is switched to enter the low current constant current charging stage until the battery voltage of the second battery reaches V2(2), and so on, until all batteries have completed the low current constant current charging stage, and then the constant voltage charging stage is entered.

[0014] In some embodiments of this application, the charging current I2(i) during the low-current constant-current charging stage can be configured to take a value between [0.3C, 0.4C]. After the i-th battery enters the low-current constant-current charging stage, the i-th battery is charged with a constant current using the charging current I2(i). The charging current in this stage is generally small, and supplementing the battery power with a low-current charging method can overcome the battery safety problems that are easily caused by long-term high-current fast charging.

[0015] In some embodiments of this application, when the battery is nearly fully charged, in order to allow the battery voltage to rise smoothly to the battery's charging cutoff voltage, the i-th battery can be charged at a constant voltage using the charging cutoff voltage corresponding to the i-th battery during the constant voltage charging phase, until the i-th battery finishes charging, at which point charging stops and the process switches to the next battery to enter the constant voltage charging phase.

[0016] In another aspect, the present invention also proposes an electronic product comprising multiple batteries and a charging module; the charging module controls the charging of the multiple batteries according to the following process: Control multiple batteries to enter and complete the high-current constant-current charging stage in sequence; Control the multiple batteries to sequentially enter and complete the adjustment charging stage; Control the multiple batteries to sequentially enter and complete the low-current constant-current charging stage; Control the multiple batteries to sequentially enter the constant voltage charging stage until charging is completed; The high-current constant-current charging stage, the adjustment charging stage, the low-current constant-current charging stage, and the constant-voltage charging stage are defined in the battery charging curve, which is formulated based on the battery's own characteristics. The adjustment charging stage is a transition stage from the high-current constant-current charging stage to the low-current constant-current charging stage. In the adjustment charging stage, the battery charging current decreases from the charging current of the high-current constant-current charging stage to the charging current of the low-current constant-current charging stage.

[0017] Compared with the prior art, the advantages and positive effects of the present invention are mainly reflected in: This invention subdivides the constant current charging stage of the battery into two parts: a high-current constant current charging stage and a low-current constant current charging stage. An adjustment charging stage is designed between the two constant current charging stages to achieve a smooth transition of the charging current. This can solve the impact of long-term high-current fast charging on battery charging safety and ensure battery charging safety.

[0018] This invention controls multiple batteries to alternately enter a high-current fast charging phase, enabling multiple batteries to rapidly increase their battery capacity in a very short time. Subsequently, by controlling the multiple batteries to sequentially enter an adjustment charging phase, a low-current constant-current charging phase, and a constant-voltage charging phase, the multiple batteries can successively reach full charge at short time intervals.

[0019] Applying the multi-battery charging method of the present invention to electronic products equipped with multiple batteries enables the electronic products to obtain the maximum charging capacity within a limited time, achieving long battery life with short charging time and improving the user experience.

[0020] Other features and advantages of the present invention will become clearer after reading the detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a waveform diagram of one embodiment of a battery charging curve; Figure 2 This is a flowchart of an embodiment of the multi-battery charging method proposed in this invention; Figure 3 This is a flowchart of the charging control process after the battery enters the adjustment charging stage. Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] Considering the battery safety issues arising from large battery capacity, high charging current during the constant current phase, and long charging duration, this embodiment first adjusts the traditional constant current charging phase by employing a step-charge strategy to subdivide the constant current charging phase. For example, it can be subdivided into two constant current charging phases: a first phase with high current and a second phase with low current. The transition between the two phases is achieved by adjusting the charging phase. That is, the first constant current phase transitions to the second constant current phase through this adjustment. During the adjustment phase, the charging current is primarily adjusted to achieve a smooth decrease, thereby reducing the impact on the battery. This segmentation technique ensures battery charging safety, but the charging time is slightly longer compared to the traditional technique of maintaining a high current constant current for an extended period, which slightly affects charging efficiency.

[0026] By applying the Step Charge technology to the charging process of multiple batteries, the charging order of multiple batteries is adjusted to control the multiple batteries to alternately enter the high-current fast charging stage. As a result, the capacity of all batteries can be greatly increased in the early stage of charging, and then the maximum charging capacity can be obtained within a limited charging time.

[0027] The following is a combination of... Figure 1 The battery charging curve illustrates the various stages the battery goes through during the charging process.

[0028] This embodiment divides the entire battery charging process into a high-current constant current charging stage FCC1, an adjustment charging stage SC, a low-current constant current charging stage FCC2, and a constant voltage charging stage FCV. Alternatively, a trickle charging stage can be added after the constant voltage charging stage FCV, which can be selected according to actual needs.

[0029] The high-current constant-current charging stage (FCC1) is the high-current fast charging stage. During this stage, a larger charging current can be used to quickly charge the battery, rapidly increasing its charge capacity.

[0030] In this embodiment, the charging current of FCC1 during the high-current constant-current charging stage can be configured to be between [0.9C, 1C), where C is the current value corresponding to the battery's rated capacity. For example, for a battery with a rated capacity of 3600mAh, its C = 3600mA. When charging this battery with a high current, the charging current can be increased to between 3240mA and 3600mA to quickly increase the battery capacity. For example, the battery capacity can be quickly increased from near 0 to over 60%.

[0031] In other words, most of the battery's capacity is replenished during the high-current constant-current charging phase (FCC1). Therefore, for electronic products with multiple batteries, it is essential to make full use of the high-current constant-current charging phase (FCC1) to significantly improve the product's battery life within a limited time.

[0032] The adjustment charging stage SC is the transition stage from the high current constant current charging stage FCC1 to the low current constant current charging stage FCC2. In this stage, the main adjustment is to adjust the magnitude of the charging current to achieve a smooth transition from high current to low current.

[0033] In some embodiments, the change curve of the charging current in the charging phase SC can be configured as a sloping line starting from the charging current of the high-current constant current charging phase FCC1 and ending with the charging current of the low-current constant current charging phase FCC2, so as to achieve a steady decrease in the charging current.

[0034] During the SC (Sustainable Charging) phase, the battery level can be increased from 60% to around 80%, which is also a crucial period for the battery to rapidly increase its capacity.

[0035] The low-current constant-current charging stage of FCC2 also involves constant-current charging of the battery. However, compared to the high-current constant-current charging stage of FCC1, its charging current is smaller, typically configured between 0.3C and 0.4C. Replenishing battery power using low-current charging can overcome the battery safety issues that can easily arise from prolonged high-current fast charging.

[0036] During the low-current constant-current charging phase of FCC2, the battery capacity can be increased from about 80% to about 95%, which is also a critical period for the battery to rapidly increase its capacity.

[0037] The constant voltage charging (FCV) stage charges the battery with a constant voltage. During this stage, the charging voltage can be configured to match the battery's charging cutoff voltage to control the battery charge to slowly reach 100%.

[0038] For a battery charging curve with a trickle charging stage, the battery enters the trickle charging stage after the constant voltage charging stage (FCV) to compensate for the capacity loss caused by self-discharge after the battery is fully charged.

[0039] The following is combined with Figure 1 The battery charging curve shown illustrates the multi-battery charging method of this embodiment in detail.

[0040] Suppose that an electronic product contains n batteries, where n is a positive integer greater than 1. Each battery has a customized charging curve based on its own characteristics, and each battery charging curve includes a high-current constant-current charging stage, an adjustment charging stage, a low-current constant-current charging stage, and a constant-voltage charging stage.

[0041] Select the first battery from n batteries as the primary battery, and the rest as secondary batteries. If there are multiple secondary batteries, their charging order needs to be preset with a priority. During normal use, the primary battery powers the system as long as it has power. Only when the primary battery's charge drops to a lower limit will the system automatically switch to a secondary battery to continue powering it.

[0042] A charging module is configured in the electronic product, connected to an external power source. This module controls the charging of all batteries within the product. The control method can be found in [reference needed]. Figure 2 Specifically, it includes the following processes: S201, Control multiple batteries to sequentially enter and complete the high-current constant-current charging stage FCC1.

[0043] When multiple batteries in an electronic product need to be charged, according to the preset priority, the battery with the higher priority is controlled to enter the high current constant current charging stage FCC1 first, and after the high current constant current charging process of the battery is completed, the low priority battery is switched to enter the high current constant current charging stage FCC1.

[0044] For example, if an electronic product is equipped with two batteries, a main battery and a secondary battery, and both batteries need to be charged, the main battery is first controlled to enter the high-current constant-current charging stage FCC1. After the main battery completes the high-current constant-current charging process, the charging of the main battery is paused, and the secondary battery is switched to enter the high-current constant-current charging stage FCC1. The process continues until the secondary battery completes the high-current constant-current charging process, at which point process S202 is executed.

[0045] If an electronic product is equipped with a main battery and multiple auxiliary batteries, after the product has been used for a period of time, the main battery may be depleted, some auxiliary batteries may be depleted or partially depleted, while the remaining auxiliary batteries may be fully charged. In this case, to charge the electronic product, only the main battery and the depleted / partially depleted auxiliary batteries need to be charged. Specifically, the main battery is first controlled to enter the high-current constant-current charging stage FCC1. After completing the high-current fast charging, the system switches to the auxiliary batteries. According to priority, higher-priority auxiliary batteries enter the high-current constant-current charging stage FCC1 first, and after completing the high-current fast charging in this stage, the system switches to lower-priority auxiliary batteries for the high-current constant-current charging process. This continues until all partially depleted auxiliary batteries have completed the high-current constant-current charging process, at which point process S202 is executed. Fully charged auxiliary batteries do not participate in this round of charging.

[0046] To determine whether the battery has completed the high-current constant charging process, this embodiment proposes the following method: First, based on the battery charging curve of each battery, determine the battery voltage value that FCC1 needs to reach during the high-current constant-current charging stage of each battery, denoted as V1(i).

[0047] For example, for a lithium battery with a charging cutoff voltage of 4.4V, V1(i) is generally set to 4.2V.

[0048] Then, the battery is charged with the charging current I1(i) configured by FCC1 during the high-current constant-current charging stage.

[0049] Here, I1(i) represents the charging current value corresponding to FCC1 during the high-current constant-current charging phase of the i-th battery. Preferably, I1(i) = 0.9C, where C is the current value corresponding to the rated capacity of the i-th battery.

[0050] For example, if the rated capacity of the i-th battery is 3600mAh, then the charging current of FCC1 during the high-current constant-current charging stage is I1(i) = 0.9 * 3600mA = 3240mA.

[0051] During high-current constant charging, the battery voltage continuously increases. For a 4.4V lithium battery, its voltage can typically rise from 3V to 4.2V.

[0052] The battery voltage of the i-th battery is monitored in real time. When the battery voltage reaches V1(i), it indicates that the i-th battery has completed the high-current constant charging process. At this time, charging of the i-th battery can be paused, and the process can be switched to the high-current constant charging stage FCC1 for the (i+1)-th battery.

[0053] After all batteries that need charging have completed the high-current constant-current charging process, the subsequent process is executed.

[0054] S202, Control multiple batteries to enter and complete the adjustment charging stage SC in sequence.

[0055] According to the priority order, the battery with the highest priority is first controlled to enter the adjustment charging stage SC. After the charging of this stage is completed, the battery with the lowest priority is switched to enter the adjustment charging stage SC. This process is repeated until all batteries that need to be charged have completed the charging of this stage, and then process S203 is executed.

[0056] During the SC (Sequencing and Charging) adjustment phase, the change in charging current over time for each battery can be determined based on its charging curve. The batteries are then charged according to the specified charging current. In this phase, the charging current gradually decreases, the battery voltage slowly increases, and the battery capacity rapidly increases.

[0057] How to control the battery to end the adjustment charging process at the right time, combined with Figure 3 As shown, this embodiment proposes the following method: S301. Obtain the charging current I2(i) configured for each battery during the low-current constant-current charging stage, i=1,2,……,n.

[0058] S302. Configure the setting threshold STEP_I.

[0059] In this embodiment, the setting threshold STEP_I can take values between 10% and 20% of I2(i).

[0060] For example, for a 3600 mAh battery, the charging current I2(i) in the small current constant current charging stage FCC2 is generally configured to be about 0.3C, that is, I2(i) = 0.3 * 3600 mA = 1080 mA. In this case, the setting threshold STEP_I = 100 mA or STEP_I = 200 mA can be configured so that the charging current at the end of the adjustment charging stage SC can be as close as possible to the charging current I2(i) after the battery enters the small current constant current charging stage FCC2.

[0061] S303. Read the instantaneous charging current I of the battery every T1 time.

[0062] In this embodiment, T1 can be set to 5 seconds, that is, read the instantaneous charging current value of the battery every 5 seconds.

[0063] S304. Compare the instantaneous charging current I with I2(i) + STEP_I. If I ≥ I2(i) + STEP_I, return to step S303; if I < I2(i) + STEP_I, execute the subsequent steps.

[0064] S305. Continuously read the instantaneous charging current of the battery three times at an interval of T2, and obtain three instantaneous charging current values I1, I2, and I3 respectively; In this embodiment, T2 should be set to be less than T1, and preferably T2 = 10 ms, that is, read the instantaneous charging current of the battery every 10 ms, and read it three times continuously to obtain three instantaneous charging current values I1, I2, and I3.

[0065] S306. Calculate the differences between the three instantaneous charging current values I1, I2, and I3 and I2(i) respectively, and take the absolute values, denoted as △I1, △I2, and △I3.

[0066] In this embodiment, △I1, △I2, and △I3 of the i-th battery can be calculated according to the following formula: |I1 - I2(i)| = △I1; |I2 - I2(i)| = △I2; |I3 - I2(i)| = △I3.

[0067] S307. If at least one of △I1, △I2, and △I3 is greater than the set threshold STEP_I, then return to step S305; otherwise, execute the subsequent steps.

[0068] S308. When △I1, △I2, and △I3 are all less than the set threshold STEP_I, pause the charging process for the i-th battery and switch to the next battery to enter the adjustment charging stage SC.

[0069] The subsequent process will continue only after all batteries that need charging have completed the adjustment charging phase SC.

[0070] S203, control multiple batteries to enter and complete the low-current constant-current charging stage FCC2 in sequence.

[0071] According to the priority order, the battery with the highest priority is first controlled to enter the low current constant current charging stage FCC2. After the low current constant current charging is completed, the battery with the lowest priority is switched to enter the low current constant current charging stage FCC2. This process continues until all batteries that need to be charged have completed the low current constant current charging, and then process S204 is executed.

[0072] To determine whether the battery has completed the low-current constant charging process, this embodiment proposes the following method: First, based on the battery charging curve of each battery, determine the battery voltage value that FCC2 needs to reach during the low current constant current charging stage of each battery, denoted as V2(i).

[0073] For example, for a lithium battery with a charging cutoff voltage of 4.4V, V2(i) can be set as the charging cutoff voltage of the battery, that is, V2(i) = 4.4V.

[0074] Then, the battery is charged with the charging current I2(i) configured by FCC2 during the low-current constant-current charging stage.

[0075] Here, I2(i) represents the charging current value corresponding to FCC2 for the i-th battery during the low-current constant-current charging stage. The preferred configuration is I2(i) = 0.3C, where C is the current value corresponding to the rated capacity of the i-th battery.

[0076] For example, if the rated capacity of the i-th battery is 3600mAh, then the charging current of FCC2 during the low-current constant-current charging stage is I2(i) = 0.3 * 3600mA = 1080mA.

[0077] During constant charging with a small current, the battery voltage increases slowly.

[0078] The battery voltage of the i-th battery is monitored in real time. When the battery voltage reaches V2(i), it indicates that the i-th battery has completed the low-current constant charging process. At this time, charging of the i-th battery can be paused, and the process can be switched to the (i+1)-th battery to enter the low-current constant charging stage FCC2.

[0079] After all batteries that need charging have completed the low-current constant-current charging process, the subsequent process is executed.

[0080] S204. Control multiple batteries to enter the constant voltage charging stage FCV in sequence until charging is completed.

[0081] According to the priority order, the battery with the highest priority is first controlled to enter the constant voltage charging stage FCV. After the constant voltage charging is completed, the battery with the lowest priority is switched to enter the constant voltage charging stage FCV. This process is repeated until all batteries that need to be charged have completed constant voltage charging, and then the charging process ends.

[0082] During this stage, each battery is charged at a constant voltage using the charging cutoff voltage corresponding to that battery until the battery reaches 100% charge. Then, charging stops, and the process switches to the next battery to enter the constant voltage charging stage (FCV).

[0083] For example, for a lithium battery with a charging cutoff voltage of 4.4V, after it enters the constant voltage charging stage (FCV), the battery is charged using a charging voltage of 4.4V until the battery is fully charged, at which point the charging process ends.

[0084] It should be noted that, for cases with a trickle charging stage, the trickle charging stage can be entered sequentially after all batteries have completed constant voltage charging, in order to compensate for the capacity loss caused by self-discharge after the battery is fully charged.

[0085] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A multi-battery charging method, characterized by, Including: Formulating a battery charging curve according to the characteristics of the battery itself, and the battery charging curve at least includes a large current constant current charging stage, an adjustment charging stage, a small current constant current charging stage, and a constant voltage charging stage; wherein, the adjustment charging stage is a transition stage from the large current constant current charging stage to the small current constant current charging stage. In the adjustment charging stage, the charging current curve of the battery is an oblique line starting from the charging current in the large current constant current charging stage and ending at the charging current in the small current constant current charging stage. Controlling multiple batteries to sequentially enter and complete the large current constant current charging stage. Controlling the multiple batteries to sequentially enter and complete the adjustment charging stage. Controlling the multiple batteries to sequentially enter and complete the small current constant current charging stage. Controlling the multiple batteries to sequentially enter the constant voltage charging stage until the charging ends.

2. The multi-battery charging method according to claim 1, characterized in that, In the large current constant current charging stage, According to the battery charging curve of each battery, determining the battery voltage value V1(i) that each battery needs to reach in the large current constant current charging stage, i = 1, 2, ……, n, where n is the number of batteries. Controlling the first battery to enter the large current constant current charging stage, and pausing the charging when the battery voltage of the first battery reaches V1(1), switching to the second battery to enter the large current constant current charging stage until the battery voltage of the second battery reaches V1(2), and so on. Until all batteries complete the large current constant current charging stage, then enter the adjustment charging stage.

3. The multi-battery charging method according to claim 2, wherein Configuring the charging current I1(i) in the large current constant current charging stage to take values between [0.9C, 1C); where C is the current value corresponding to the rated capacity of the battery. After the i-th battery enters the large current constant current charging stage, charging the i-th battery with a constant current of charging current I1(i).

4. The multi-battery charging method according to any one of claims 1 to 3, characterized in that, In the adjustment charging stage, Monitoring the charging current of the i-th battery. When the difference between the charging current and I2(i) is less than the set threshold STEP_I, pausing the charging and switching to the next battery to enter the adjustment charging stage; where I2(i) is the charging current value configured for the i-th battery in the small current constant current charging stage.

5. The multi-battery charging method according to claim 4, characterized in that, After the i-th battery enters the adjustment charging stage, Reading the instantaneous charging current I of the i-th battery every T1 time. When the instantaneous charging current I < I2(i) + STEP_I, continuously reading the instantaneous charging current of the i-th battery three times, and the interval time is T2, T2 < T1, and three instantaneous charging current values I1, I2, and I3 are obtained respectively. Calculating the differences between the three instantaneous charging current values I1, I2, and I3 and I2(i) respectively and taking the absolute values, which are denoted as △I1, △I2, and △I3 respectively. If at least one of △I1, △I2, and △I3 is greater than the set threshold STEP_I, then continuously reading the instantaneous charging current of the i-th battery three times again, and calculating △I1, △I2, and △I3 until △I1, △I2, and △I3 are all less than the set threshold STEP_I, then the i-th battery pauses charging and switches to the next battery to enter the adjustment charging stage.

6. The multi-battery charging method according to claim 5, characterized in that, T1 = 5 seconds; T2 = 10 ms; the set threshold STEP_I is between 10% and 20% of I2(i).

7. The multi-battery charging method according to any one of claims 1 to 3, characterized in that, During the low-current constant-current charging phase Based on the battery charging curve of each battery, determine the battery voltage value V2(i) to be reached by each battery in the low current constant current charging stage, i=1,2,……,n, where n is the number of batteries; The first battery is controlled to enter the low-current constant current charging stage, and charging is paused when the battery voltage of the first battery reaches V2(1). The charging is then switched to the second battery to enter the low-current constant current charging stage until the battery voltage of the second battery reaches V2(2). This process is repeated until all batteries have completed the low-current constant current charging stage, and then the constant voltage charging stage is entered.

8. The multi-battery charging method according to claim 7, characterized in that, The charging current I2(i) during the low-current constant-current charging stage is configured to take a value between [0.3C, 0.4C]; where C is the current value corresponding to the rated capacity of the battery; After the i-th battery enters the low-current constant-current charging stage, the i-th battery is charged with constant current using charging current I2(i).

9. The multi-battery charging method according to any one of claims 1 to 3, characterized in that, During the constant voltage charging phase, each battery is charged at a constant voltage using the charging cutoff voltage corresponding to that battery until the charging of that battery is finished. Then, the charging stops and the process switches to the next battery to enter the constant voltage charging phase.

10. An electronic product comprising multiple batteries and a charging module; characterized in that, The charging module controls the charging of the multiple batteries according to the multi-battery charging method as described in any one of claims 1 to 9.

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