Battery failure judgment method based on trigger signal and cross-time-domain internal resistance

Abstract

The invention discloses a battery failure judgment method based on a trigger signal and cross-time-domain internal resistance, and the method comprises the steps: arranging a metal detection sheet on the surface of a battery, keeping the metal detection sheet at a high level, and monitoring the level change of the metal detection sheet through a detection circuit; a battery bump contact event is determined upon detection of a steady transition from a high level to a low level. And on the basis, controlling the charging module to apply constant current to the battery, acquiring steady-state charging voltage, acquiring second voltage after stopping charging and delaying for Tdelay, and calculating the cross-time-domain internal resistance R of the battery through a formula. And judging whether the battery is in a failure state or not according to a comparison result of the obtained internal resistance and a preset threshold Rth, and executing system-level protection measures such as charging interruption, power limitation, event log recording or abnormality reporting and the like when the battery is in failure. According to the invention, physical bump contact detection and electrochemical cross-time-domain internal resistance measurement are combined, and accurate determination of bumps and internal degradation can be realized on the premise of not disassembling a machine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery safety management, and particularly relates to a battery failure judgment method based on a trigger signal and a cross-time domain internal resistance. BACKGROUND

[0002] With the increasing trend of high integration of consumer electronic devices, power tools and portable terminals, a large number of products use lithium battery packages with non-detachable structure. Once the shell is formed, the user and the maintenance personnel cannot directly observe the actual state of the battery, especially cannot judge in real time whether the battery has risks such as bulging, internal gas accumulation or electrochemical performance degradation. The common monitoring method in the industry mostly relies on temperature sensors, voltage fluctuations, SOC algorithm and other software estimation methods, but these methods are essentially "indirect judgment" and can only be identified when the battery cell has obvious abnormalities or signs of thermal runaway, which is a delayed reaction and has a high misjudgment rate.

[0003] Existing bulging detection schemes are also not ideal. Some devices try to use shell micro-deformation, pressure sensors or shell stress distribution to judge bulging, but these schemes are difficult to be compatible with the current lightweight design in structure, and have high cost, poor durability, large signal noise, and are easily affected by environmental temperature, external pressure or structural tolerance. More importantly, these methods can only "see the bulging", but cannot judge whether the internal electrochemical system has degraded, and cannot provide any quantitative indicators. Therefore, relying solely on mechanical deformation detection cannot support the device to make effective protection strategies.

[0004] On the other hand, as an important parameter for evaluating the health status, the battery internal resistance can be measured by professional instruments in an experimental environment, but it is difficult to obtain in real time, stably and at low cost in actual products. Existing devices generally use transient sampling, curve fitting or temperature correction to estimate the internal resistance, which is extremely sensitive to load changes and is easily affected by voltage polarization and other transient effects, resulting in large measurement result drift and poor reproducibility. The same problem leads to the fact that internal resistance cannot be used as the main safety indicator in actual products.

[0005] Therefore, the existing technology generally has three common deficiencies: First, there is a lack of a low-cost, long-term working structure that can reliably detect bulging events in a closed device. Second, there is a lack of an engineering solution that can stably and repeatedly measure the battery internal resistance in the product operating environment. Third, there is a lack of a mechanism for combining "physical bulging" and "internal degradation" for comprehensive risk judgment.

[0006] In this context, the industry has been in a "dilemma" for a long time: visible bulge, but not sure whether to protect; can estimate the internal resistance, but cannot determine whether it is related to the bulge. The existing technology cannot solve these two problems at the same time, so it is difficult to truly achieve effective safety management. Based on this, it is necessary to provide a method that can accurately determine the battery failure under the condition of not disassembling by combining the repeatable physical trigger signal with the cross-time domain voltage decay characteristic, so as to improve the reliability and safety of the equipment.

[0007] Therefore, the prior art still needs to be improved. SUMMARY

[0008] In view of the obvious short board of the prior art in the aspects of bulge identification reliability, battery internal resistance measurement stability and lack of linkage determination mechanism between the two, it is difficult to support the equipment to make accurate risk judgment in the early stage, therefore it is necessary to put forward a comprehensive determination method that can simultaneously use the bulge contact signal and the change of electrochemical characteristics. The present application is based on this demand, through the combination of physical contact trigger and cross-time domain voltage decay analysis, the equipment can obtain more reliable failure evidence under the premise of not disassembling, so as to realize the accurate identification of the battery health state.

[0009] The technical scheme of the present application is as follows: The present application provides a battery failure determination method based on trigger signal and cross-time domain internal resistance, comprising: S1, arranging a metal detection sheet on the surface of the battery, and maintaining the metal detection sheet at a stable high level through a detection circuit; S2, monitoring the level change of the metal detection sheet, when the transition from high level to low level is detected and continues for more than a first set time in a preset anti-jitter window , it is determined that the battery has a bulge contact event; S3, after determining the bulge contact event, controlling the charging module to apply a constant charging current to the battery , and measuring a first voltage after reaching a steady state ; S4, stopping charging, and measuring a second voltage after a set delay Tdelay ; S5, calculating the battery cross-time domain internal resistance R according to the formula ; S6, comparing the internal resistance R with a preset internal resistance threshold R_th, when R >= R_th, determining that the battery is in a failure state, and performing at least one system-level battery protection measure.

[0010] In one embodiment, the metal detection sheet maintains an initial gap with the internal metal interface of the device through the flexible support, and the local shell bulge caused by the battery bump breaks through the initial gap and forms a conduction, causing the level to jump.

[0011] In one embodiment, the detection circuit includes a comparator input, a pull-up resistor and an MCU analog sampling terminal, and the anti-interference determination of the level change is realized by the combination of hardware RC filtering and MCU software window filtering.

[0012] In one embodiment, the Tdelay is 0.5-5 seconds, which is used to eliminate the polarization effect of the battery after stopping the constant current charging and obtain an approximately stable open circuit voltage.

[0013] In one embodiment, the method further includes setting a pre-warning threshold R_warn, and when R_warn≤R<R_th, determining that the battery is in a degraded state and limiting the maximum allowed discharge power of the battery.

[0014] In one embodiment, the R_th is determined by the reference internal resistance curve of the battery under factory calibration conditions, the device use environment temperature and the number of battery cycles, and can be dynamically self-calibrated according to historical operation data.

[0015] In one embodiment, the constant current The value of the constant current is 0.1C-0.5C of the battery capacity C.

[0016] In one embodiment, the second voltage The second voltage is an approximately open circuit voltage obtained after stopping the constant current charging for Tdelay, which is used to represent the slow time domain voltage recovery characteristics of the battery.

[0017] In one embodiment, the system-level battery protection measures include at least one of the following: Disconnecting the charging path, limiting the maximum power output of the system, recording an unalterable event log, pushing an abnormal prompt to the user or uploading abnormal data to a remote server.

[0018] In one embodiment, the method is executed in firmware through a state machine, and the state machine includes at least: The level monitoring state, the bulge confirmation state, the constant current charging measurement state, the delay sampling state, the internal resistance determination state, the pre-warning state and the failure protection state.

[0019] In summary, this invention is not simply a stacking of existing bulge detection or internal resistance measurement methods. Instead, it combines physical trigger signals with cross-time domain voltage recovery characteristics into a closed-loop judgment system based on the degradation patterns of batteries in real-world usage scenarios. The metal detection chip provides a deformation trigger point that is virtually unaffected by software strategies and can operate for extended periods. Meanwhile, the voltage decay after constant current charging accurately reflects the internal state of the electrochemical system. Together, these two elements form a dual chain of evidence that supports the device in making informed decisions. Through this structure and method, the device can promptly detect risks when bulges first appear and internal degradation has not yet reached the failure boundary. It can also quickly enter a protection state when bulges and internal resistance anomalies occur simultaneously, significantly improving overall reliability and safety management.

[0020] From an engineering feasibility perspective, the solution of this invention has extremely low hardware requirements. A detection chip and a simple comparison circuit are sufficient to trigger the bulge, and the cross-time domain measurement step can be implemented using existing charging links and MCUs, without the need for additional complex sensors or expensive components. This makes it more suitable for deployment in mass-produced products. Overall, this invention possesses strong practical operability and provides a more direct and reliable basis for judging the battery degradation process, effectively filling the gaps in existing technologies for battery health management.

[0021] Compared to existing methods that rely on temperature, voltage fluctuations, or software models to estimate battery health, this invention offers significant, even unconventional, improvements. Firstly, the bulging contact signal generated by the metal detection plate has a very clear trigger point, unaffected by temperature drift, SOC deviation, or load fluctuations. In actual testing, it exhibits a characteristic of "stable triggering whenever bulging occurs," a feature far beyond what traditional casing stress detection or noise curve-based judgment methods can achieve. In other words, this invention transforms bulging—a phenomenon often considered "visible but unquantifiable"—into a reliably detectable hard-triggered event.

[0022] Secondly, and more unexpectedly, the battery's internal polarization and electrochemical recovery characteristics reflected by the voltage decay across the time domain after constant current charging show a highly consistent degradation trend with the physical deformation of bulging. Traditionally, it was believed that there was no direct correlation between cell deformation and changes in internal resistance, and that the relationship was more of a coincidental overlap; however, actual verification revealed that the accuracy of determining the superposition of these two factors was significantly improved. The voltage difference measured across the time domain... When combined with the bulge contact signal, the overall misjudgment rate decreased significantly. This combination of "physical event + electrochemical indicator" has not been systematically proposed in existing technologies, nor has it been widely recognized by the industry.

[0023] Furthermore, the cross-time domain internal resistance calculation method used in this invention has extremely low dependence on the device's operating state. Even under different temperature and load conditions, it can maintain high consistency, and is actually much more stable than traditional transient internal resistance estimation. Its engineering repeatability far exceeds expectations. This stability comes from the voltage range that the battery naturally recovers after the Tdelay, which is precisely the area that traditional technologies rarely utilize or even consider unnecessary to focus on.

[0024] Finally, the overall technical approach of this invention is almost negligible in cost, has a simple structure, yet obtains a complete and reliable chain of evidence for battery failure, enabling the device to identify potential risks at an early stage. From an engineering perspective, this is a technical approach that "seems simple, but its actual effect far exceeds that of conventional solutions." This effect of achieving high confidence levels with extremely low hardware investment is something that is difficult to foresee in existing technologies. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Fig. 1 The present invention provides a flowchart of the steps of a battery failure determination method based on trigger signal and cross-time domain internal resistance. Fig. 2 A schematic diagram of the charging process structure of a battery failure judgment method based on trigger signal and cross-time domain internal resistance provided by the present invention; Fig. 3 This is a schematic diagram showing the comparison of the battery failure structure before and after failure, which is provided by the present invention for a battery failure judgment method based on trigger signal and cross-time domain internal resistance. Detailed Implementation

[0026] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The embodiments of the invention are described below in conjunction with the accompanying drawings.

[0027] This invention provides a battery failure determination method based on trigger signals and cross-time domain internal resistance. Please refer to [link to relevant documentation]. Figs. 1-3 This includes the following steps: S1. A metal detection strip is placed on the surface of the battery, and the metal detection strip is maintained at a stable high level by a detection circuit; In practical implementation, a metal detection patch can be mounted on the battery surface near the center. This location is generally less affected by structural interference, and deformation during bulging is more noticeable. The detection patch can be a 10–30 μm thick tin-plated copper foil, fixed to the battery casing label surface with high-temperature resistant double-sided adhesive. To prevent peeling or oxidation during use, a PET film can be added to the outside of the detection patch for protection. The detection circuit maintains the node where the detection patch is located at a stable high level through a pull-up resistor (such as 10kΩ or 47kΩ). The MCU reads this node at 1–5ms intervals to capture level changes caused by bulging as early as possible. This arrangement does not change the original battery structure and adds virtually no cost.

[0028] In a further embodiment, the method further includes: S2. Monitor the level change of the metal detection strip. When a transition from high level to low level is detected and continues for more than a first set time within a preset anti-jitter window, At that time, it was determined that a battery bulging contact event had occurred; During long-term operation, a safety gap of approximately 0.15–0.25 mm is maintained between the detection pad and the internal reference metal surface. When the battery bulges, a slight bulge forms in the casing. This minute displacement will first press the detection pad, causing it to contact the metal surface and resulting in a momentary change in the node voltage from high to low. To ensure that the judgment is not affected by momentary jitter or accidental contact, the MCU will perform at least [further processing / processing] on this low level. For example, a continuous confirmation period of 20-30ms is required. Only after confirming that the voltage level remains low throughout this period will the event be considered a genuine bulge trigger. Actual testing shows that this determination method is stable in long-term use and multi-scenario stress testing, with no false alarms.

[0029] In a further embodiment, the method further includes: S3. After determining the bulge contact event, control the charging module to apply a constant charging current to the battery. And the first voltage was measured after reaching steady state. ; After confirming the bulging event, the system does not immediately perform complex judgments, but directly switches the charging management chip to constant current mode to obtain a set of sufficiently stable measurement data. Constant current. The current is typically set between 0.1C and 0.5C based on the battery capacity, with the specific value chosen depending on the device model and heat dissipation requirements. For example, a 3000mAh battery could be set to 600mA. Once the current enters a stable range (usually within 50-200ms), the MCU directly samples the steady-state voltage from the charging port as the first voltage. The steady-state value is chosen because the battery terminal voltage at this point better reflects the internal equivalent series impedance and is not affected by transient disturbances.

[0030] In a further embodiment, the method further includes: S4. Stop charging and measure the second voltage after the set delay Tdelay. ; After collection Then, charging is immediately stopped by turning off the charging switch. In the first few tens of milliseconds after stopping, the battery voltage drops rapidly, a typical behavior caused by polarization release. To avoid misinterpreting these rapid changes as the battery's true internal resistance characteristics, the system waits for Tdelay (e.g., 1-3 seconds) to allow the voltage to enter a smoother recovery phase. Subsequently, the MCU again samples the voltage at the battery port as the second voltage. . The closer the voltage is to the stable open-circuit voltage, the more accurately the subsequent calculations will reflect the changes in the battery's internal impedance.

[0031] In a further embodiment, the method further includes: S5. According to the formula Calculate the battery's internal resistance R across the time domain; The system uses formulas Calculate the battery's internal resistance across the time domain. This formula essentially uses the voltage difference between the constant-current charging transient and the short-time recovery process to estimate the equivalent impedance. Unlike traditional transient methods, this cross-time domain approach is less affected by noise, load fluctuations, and sampling jitter, reflecting the battery's internal impedance level more closely resembles its true chemical state. Engineering tests have shown that, in cases of slight bulging but with normal temperature, this internal resistance change typically reveals abnormal trends earlier than through transient sampling alone.

[0032] In a further embodiment, the method further includes: S6. Compare the internal resistance R with the preset internal resistance threshold R_th. When R ≥ R_th, determine that the battery is in a failure state and execute at least one system-level battery protection measure.

[0033] After calculating the internal resistance, the system compares the obtained R with the preset failure threshold R_th. If R ≥ R_th, it indicates that the battery has undergone significant internal degradation or poses a potential risk. In this state, the device immediately implements protective measures, including shutting down the charging path, limiting system power output to reduce the battery's workload, writing an immutable log for subsequent analysis, and pushing notifications to the user. If the device has remote connectivity, it will also report relevant data to the cloud, enabling the maintenance system to track the battery's status and initiate recall or repair procedures when necessary. The entire action chain is executed with safety as the top priority, ensuring that the bulging battery does not continue to operate in a high-risk state.

[0034] In a further embodiment, the metal detection plate maintains an initial gap with the internal metal mating surface of the device through a flexible support. The local bulge of the outer shell caused by the battery swelling breaks through the initial gap and forms a conduction, causing the voltage level to transition.

[0035] In one feasible embodiment, the metal detection strip is not directly attached to the metal mating surface inside the device, but is maintained at an initial gap with the metal mating surface by a flexible support member with resilience.

[0036] The flexible support can be made of 0.1–0.25 mm foamed buffer material or low-hardness silicone pad. Its function is not to provide structural strength, but to ensure that the detection pad does not prematurely contact the metal surface due to slight bending of the casing before bulging occurs. The size of the support is generally controlled within a small range (e.g., 4 mm × 8 mm) to maintain the clearance without affecting the battery assembly space.

[0037] During installation, one side of the detection plate is fixed to the battery surface, while the other side maintains a fine distance from the position corresponding to the flexible support. When the battery bulges, a local bulge appears in the casing, pushing the detection plate and compressing the support, which in turn pushes the detection plate into contact with the metal surface, ultimately causing the voltage level to jump from high to low.

[0038] This "micro-distance + elastic holding" method can effectively reduce false triggering caused by noise contact, and can ensure a single causal relationship between the triggering action and the bulging behavior, which is more in line with the requirements of safety monitoring in engineering.

[0039] In a further embodiment, the detection circuit includes a comparator input, a pull-up resistor, and an MCU analog sampling terminal, and uses a combination of hardware RC filtering and MCU software window filtering to achieve anti-interference determination of level changes.

[0040] In a typical implementation, the detection circuit consists of the following structure: A pull-up resistor (Rpull-up, value 10kΩ~47kΩ) pulls the detection node to a high level; A low-power comparator with its positive terminal connected to the detection node and its negative terminal connected to a reference level (e.g., a 0.6V / 1.0V reference). An RC filter network, with R typically 1kΩ to 4.7kΩ and C typically 10 to 47nF, is used to eliminate spike interference; The MCU samples the comparator output via GPIO or ADC.

[0041] In terms of operational logic, the comparator is used for fast hardware-level determination, the RC circuit is used for physical interference suppression, and the MCU software further performs window filtering and duration determination on the sampling results. For example, the MCU will detect whether the comparator output remains at a low level for more than [a certain period of time]. (e.g., 20ms), and determine whether a secondary confirmation process is needed by combining the continuity of sampling of several frames before and after.

[0042] This combined structure has stronger anti-jitter capability compared to simple GPIO sampling, and can maintain high accuracy even in environments with a lot of electromagnetic interference or when the battery casing is slightly deformed.

[0043] Therefore, this structure can meet the dual requirements of real-time performance and reliability in triggering bulges.

[0044] In a further embodiment, the Tdelay is 0.5–5 seconds, which is used to eliminate the polarization effect and obtain an approximately stable open-circuit voltage after the constant current charging stops.

[0045] In practice, the system does not immediately sample the second voltage after stopping constant current charging. Instead, it waits for the set delay Tdelay.

[0046] The selection of Tdelay is based on the battery's voltage recovery curve after charging is stopped: 0–300 ms: The rapid dissipation phase of polarization is not suitable for measurement; 300ms~2s: The curve enters the slow recovery zone, which is the core area for acquiring stable data; If it takes more than 3 to 5 seconds, the voltage change will slow down, but the user's waiting time is too long, which is not conducive to the detection experience.

[0047] Therefore, in this embodiment, Tdelay is set to 1-3 seconds, and sampling is performed at this time point. This ensures that it is close to a short-term open-circuit state, which helps to pass through The trans-time domain internal resistance is calculated to be closer to the true chemical impedance.

[0048] In terms of the sampling method, the MCU directly reads the battery port voltage and takes multiple quick samples (e.g., 3 to 5 times) and then takes the median or average value to avoid any transient noise. If the temperature or load of the device fluctuates significantly at this time, the firmware will mark it as an abnormal measurement and delay the retest to ensure the validity.

[0049] In a further embodiment, the method further includes setting a warning threshold R_warn. When R_warn ≤ R < R_th, it is determined that the battery is in a degraded state and the maximum allowable discharge power of the battery is limited.

[0050] In this embodiment, in addition to R_th, the system also sets a warning threshold R_warn for making a protection action in advance in the state of "not completely failed but already significantly exceeded the standard".

[0051] R_warn is obtained from the battery factory calibration data or the impedance statistical data of long-term operation, and is generally set to 60% - 85% of R_th.

[0052] After the system calculates the cross-time-domain internal resistance R and performs temperature compensation, it will judge in turn: If R < R_warn: It is considered that the battery is normal; If R_warn ≤ R < R_th: It is determined as the "degraded state"; [[ID=The ID=19]]If R ≥ R_th: It is determined as the "failed state".

[0053] When the battery enters the degraded state, the system does not immediately cut off the charging, but performs lightweight protection actions, such as: 1. Limit the maximum discharge current (e.g., reduce the peak output by 10% - 30%); 2. Reduce the transient load of high-power modules such as the CPU or motor; 3. Reduce the maximum charging current Icharge_max; 4. Record this state in the device's health monitoring log for subsequent traceability.

[0054] This "two-level protection" strategy can enable the device to reduce risks in advance when the battery enters the decline stage, and at the same time will not prematurely affect the user experience, and is more in line with the safety strategy design habits of mass-produced devices.

[0055] In a further embodiment, R_th is jointly determined by the reference internal resistance curve of the battery under the factory calibration conditions, the device usage environment temperature, and the battery cycle count, and can be dynamically self-calibrated according to historical operation data.

[0056] In a practically workable implementation, the failure threshold R_th is not a fixed value, but is determined based on the impedance curve calibrated at the battery's factory, the impedance drift under different temperature conditions, and the cycle count data accumulated over long-term operation of the equipment.

[0057] During the production phase, the battery module's reference impedance R0 is measured once in a standard environment at 25°C. The system writes this value into the device's health storage area, which serves as a baseline for subsequent failure assessment. As the device is used, the system reads the cycle count (e.g., through the internal charge / discharge statistics module) and adjusts R_th appropriately based on historical statistical models. For example, when the cycle count exceeds 300, the system can increase R_th by 10–15 mΩ to reflect a reasonable increase in the "natural aging" component.

[0058] Temperature also affects impedance determination. At low temperatures, the cell impedance itself will increase significantly. Therefore, the system will appropriately increase R_th (e.g., increase by 5–10%) when the temperature is below 15℃, while keeping the baseline value unchanged in high-temperature scenarios (>40℃) to avoid ignoring potential abnormal risks.

[0059] Overall, R_th is dynamically updated through methods such as table lookup, linear correction, or moving average, ensuring that the system maintains high reliability in different usage stages.

[0060] In a further embodiment, the constant current The value is between 0.1C and 0.5C of the battery capacity C.

[0061] In a typical implementation, to ensure the stability of the cross-time domain internal resistance calculation, a constant current is used. Set to a range of 0.1C to 0.5C based on the battery capacity C. For example, for a 3000mAh battery cell... You can choose between 300mA and 1500mA.

[0062] In engineering practice, the range of 0.2C–0.3C (e.g., 600–900mA) is generally preferred because: 1. Faster voltage response, making it easier to reach steady state; 2. The battery cell will not experience excessive temperature rise due to short-term charging; 3. Lower coupling noise is beneficial for improving... The sampling accuracy; 4. It has minimal impact on users and will not significantly change the charging experience.

[0063] Before initiating constant current charging, the device checks the current temperature and SOC range (to avoid measurements at full or extremely low charge levels), and then allows the charging management chip to enter constant current mode. If the charging link does not reach a steady state within a short time, the system will automatically reduce the current. Alternatively, the steady-state waiting time can be extended to ensure the reliability of the measurement data.

[0064] In a further embodiment, the second voltage This is the approximate open-circuit voltage obtained via Tdelay after the constant current charging stops, used to characterize the slow time-domain voltage recovery characteristics of the battery.

[0065] In this embodiment, the second voltage The key focus of the data collection is to obtain the voltage information of the battery during the "slow time-domain recovery" phase after the constant current charging stops, which is used to reflect the degree of internal polarization release and electrochemical recovery.

[0066] Specifically, when the constant current stops, the cell port voltage drops rapidly, which is caused by the dissipation of interface charge. After Tdelay (e.g., 1–3 seconds), the voltage tends to stabilize. The voltage change in this range is more controlled by the internal chemical reaction rate, which is relatively mild and better reflects the true internal state of the cell.

[0067] The system will immediately perform a high-precision ADC sampling as soon as Tdelay arrives. Then, two or three more samples are taken in the following tens of milliseconds, and the results are simply averaged or the median is taken to avoid noise interference.

[0068] In engineering verification, this "approximate open-circuit voltage" can reflect the impedance change trend more stably than the traditional transient method, especially in the stage where a bulging event has occurred but internal degradation has not yet fully deteriorated. The deviation can more intuitively present the health status of the battery cell.

[0069] In a further embodiment, the system-level battery protection measures include at least one of the following: Disconnect the charging path, limit the system's maximum power output, record tamper-proof event logs, push abnormal prompts to users, or upload abnormal data to a remote server.

[0070] In a preferred embodiment, when the system determines that the battery's cross-time domain internal resistance R ≥ R_th, thus entering a "failure state," it immediately executes a series of system-level safety actions. These typically include: 1. Turn off charging path By turning off the charging switch or disabling the charging IC, the charging current is instantly reduced to 0A, thus preventing further current input to the high-resistivity battery.

[0071] 2. Limiting discharge capacity Firmware can lower the system power limit, such as by limiting the CPU peak frequency, disabling high-load algorithms in cameras, or limiting torque output in motor devices, thereby reducing risks.

[0072] 3. Record unalterable logs. The equipment will record the status of the test pieces for the day. Key data such as R, measurement time, and temperature are written to the append-only log area for use in after-sales service or quality analysis.

[0073] 4. User Prompt If the device has a screen, a message such as "Battery malfunction, please stop using and send for inspection" will pop up; if the device does not have a display, a buzzer or indicator light will be used to indicate this.

[0074] 5. Upload to the cloud (if applicable) For devices connected to the cloud platform, logs and device serial numbers are automatically uploaded so that the operations and maintenance center can monitor batch issues.

[0075] This design ensures that failed batteries will not continue to operate under high-risk conditions, while providing data support for subsequent maintenance and quality traceability.

[0076] In a further embodiment, the method is executed in firmware via a state machine, the state machine comprising at least: Level monitoring status, bulge confirmation status, constant current charging measurement status, delayed sampling status, internal resistance determination status, early warning status, and failure protection status.

[0077] In a typical firmware implementation, the entire method operates through a state machine, with explicit transition conditions between each state: 1. Normal monitoring status The system only collects the voltage level of the detection chip and does not intervene in charging. If the abnormal voltage level persists for more than [time period missing], [further action will be taken]. Then it will switch to the "bulge trigger state".

[0078] 2. Drum trigger state Perform a second confirmation (high-resistance resampling); after successful confirmation, proceed to "internal resistance measurement state".

[0079] 3. Internal resistance measurement status Constant current charging and sampling are completed sequentially. Stop charging, wait for Tdelay, collect Calculate R.

[0080] After the measurement is completed, the next state is determined based on the relationship between R, R_warn, and R_th.

[0081] 4. Warning State If R_warn ≤ R < R_th, the downgrading strategy (such as reducing the maximum discharge power and limiting the charging current) is executed, and the status and internal resistance value of the detection piece are continuously monitored periodically.

[0082] 5. Failure Protection State If R ≥ R_th, a complete protection action chain is triggered, including charging interruption, power reduction, log recording, alarm, and remote reporting.

[0083] This state is generally a locked state and can only be解除 after manual intervention by the maintenance point.

[0084] By managing the behaviors of each stage through a state machine, the response logic of the system is clearer and more controllable, facilitating stable operation in actual products and meeting the requirements of the safety certification process.

[0085] In summary, the battery failure judgment scheme proposed in this invention does not simply add a few detection logics to the original protection mechanism, but combines "physical deformation triggering" with "cross-time-domain electrochemical state variables" to form a judgment method that is closer to the true degradation path of the battery. From the layout method of the detection piece, to the signal confirmation strategy after the bulge is triggered, to the calculation of constant current charging, voltage attenuation, and cross-time-domain internal resistance, each step is designed around one goal: to enable the device to detect potential battery risks as early as possible without relying on complex sensors and without increasing additional costs.

[0086] In actual engineering practice, this combination method of double evidence chains shows a more reliable effect than the traditional method that solely relies on bulge monitoring or internal resistance estimation. The bulge trigger provides an early signal at the physical level, while the cross-time-domain internal resistance complements the quantitative judgment of the degradation intensity. After the two are superimposed, the misjudgment rate significantly decreases and the overall stability is stronger. Especially in the stage where the bulge is not obvious but the internal reaction system has already degraded, this method can capture the risk in advance and intervene in protection in the first time, reducing the failure probability of the device.

[0087] From the perspective of implementation, the hardware requirements of this invention are extremely low. The detection piece, circuit structure, and charge and discharge management all use the original components; the software logic will not bring an obvious burden to the system and is suitable for integration into the existing mass production platform. In this way, terminal manufacturers can upgrade the battery safety management level without changing the supply chain and production process.

[0088] Generally speaking, this invention provides a more feasible and robust judgment method for battery health management through a technical route with simple structure, clear logic, and predictable behaviors, and also provides a technical basis for improving the safety and reliability of subsequent products.

[0089] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A battery failure determination method based on trigger signal and cross-time domain internal resistance, characterized in that, include: S1. A metal detection strip is placed on the surface of the battery, and the metal detection strip is maintained at a stable high level by a detection circuit; S2. Monitor the level change of the metal detection strip. When a transition from high level to low level is detected and continues for more than a first set time within a preset anti-jitter window, At that time, it was determined that a battery bulging contact event had occurred; S3. After determining the bulge contact event, control the charging module to apply a constant charging current to the battery. And the first voltage was measured after reaching steady state. ; S4. Stop charging and measure the second voltage after the set delay Tdelay. ; S5. According to the formula Calculate the battery's internal resistance R across the time domain; S6. Compare the internal resistance R with the preset internal resistance threshold R_th. When R ≥ R_th, determine that the battery is in a failure state and execute at least one system-level battery protection measure.

2. The battery failure judgment method according to claim 1, characterized in that, The metal detection plate maintains an initial gap with the internal metal interface of the device through a flexible support. The local bulge of the outer shell caused by the battery swelling breaks through the initial gap and forms a conduction, causing the voltage level to transition.

3. The battery failure judgment method according to claim 1 or 2, characterized in that, The detection circuit includes a comparator input, a pull-up resistor, and an MCU analog sampling terminal. It achieves anti-interference determination of level changes through a combination of hardware RC filtering and MCU software window filtering.

4. The battery failure judgment method according to claim 1, characterized in that, The Tdelay is 0.5–5 seconds, used to eliminate polarization effects and obtain a nearly stable open-circuit voltage after the constant current charging stops.

5. The battery failure judgment method according to claim 1, characterized in that, The method further includes setting a warning threshold R_warn. When R_warn ≤ R < R_th, the battery is determined to be in a degraded state and the maximum allowable discharge power of the battery is limited.

6. The battery failure judgment method according to claim 1, characterized in that, The R_th is determined by the reference internal resistance curve of the battery under factory calibration conditions, the ambient temperature of the equipment, and the number of battery cycles, and can be dynamically self-calibrated based on historical operating data.

7. The battery failure judgment method according to claim 1, characterized in that, The constant current The value is between 0.1C and 0.5C of the battery capacity C.

8. The battery failure judgment method according to claim 1, characterized in that, The second voltage This is the approximate open-circuit voltage obtained via Tdelay after the constant current charging stops, used to characterize the slow time-domain voltage recovery characteristics of the battery.

9. The battery failure judgment method according to claim 1, characterized in that, The system-level battery protection measures include at least one of the following: Disconnect the charging path, limit the system's maximum power output, record tamper-proof event logs, push abnormal prompts to users, or upload abnormal data to a remote server.

10. The battery failure judgment method according to claim 1, characterized in that, The method is executed in firmware via a state machine, the state machine comprising at least: Level monitoring status, bulge confirmation status, constant current charging measurement status, delayed sampling status, internal resistance determination status, early warning status, and failure protection status.

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