A battery status monitoring system and monitoring method

Abstract

The present application provides a battery status monitoring system and a monitoring method, the system comprising a working strain gauge and a thermistor arranged between the contact surface of a lithium battery and a battery compartment, and a controller electrically connected to the lithium battery, the working strain gauge and the thermistor respectively; the working strain gauge is arranged between the contact surface of the lithium battery and the battery compartment, and can accurately measure the deformation data of the lithium battery when the battery compartment is subjected to force due to battery swelling; the thermistor can collect temperature data in the battery compartment, and the analog-to-digital converter of the controller can collect voltage data of the lithium battery. When the controller receives the deformation data, temperature data and voltage data, it can preliminarily determine whether the current lithium battery is in a swelling state through the deformation data, and combine the temperature data and the voltage data of the lithium battery to further determine whether the lithium battery is in a normal swelling state caused by high temperature or full charge or an abnormal swelling state caused by overcharging or over-discharging, thereby effectively improving the user experience.

Description

Technical Field

[0001] The present application relates to the technical field of lithium batteries, and in particular to a battery status monitoring system and a monitoring method. Background Art

[0002] Lithium batteries have advantages such as light weight and high energy density, and are now widely used in many fields. However, during the use of lithium batteries, abnormal conditions such as high temperature and battery bulging are inevitable. If they are not discovered in time, serious consequences such as battery spontaneous combustion and explosion may even occur. For example, overcharging of lithium batteries will cause all lithium atoms in the positive electrode material to transfer to the negative electrode material, causing the originally full grid of the positive electrode to deform and collapse, and the excessive accumulation of lithium ions in the negative electrode causes the lithium atoms to grow stump crystals, resulting in lithium battery bulging.

[0003] At present, the protection measures for lithium batteries in the market are mainly to integrate PPTC (recoverable fuse) inside the battery core or add temperature sensing devices on the surface of the battery to intervene. When the temperature of the battery core is too high or the current is too large, the PPTC will become a high-resistance state, thereby blocking the charging and discharging current of the lithium battery. The temperature sensing device can also notify the device to reduce the charging or discharging current when it detects that the temperature of the lithium battery is too high, so as to achieve the purpose of protecting the lithium battery. The above protection measures mainly protect the battery from the aspects of charging and discharging current and temperature. However, since lithium batteries will swell slightly during normal use, they may also swell in the case of overcharging and over-discharging. If the lithium battery is only protected by the charging and discharging current and temperature, it is impossible to effectively detect whether the swelling state of the lithium battery is abnormal. Summary of the invention

[0004] The purpose of the present application is to solve at least one of the above-mentioned technical defects, especially the technical defect that the prior art cannot effectively detect whether the expansion state of the lithium battery is abnormal.

[0005] The present application provides a battery status monitoring system, the system comprising: a working strain gauge and a thermistor arranged between a lithium battery and a contact surface of a battery compartment, and a controller electrically connected to the lithium battery, the working strain gauge, and the thermistor respectively;

[0006] The controller is used to receive the deformation data of the lithium battery collected by the working strain gauge, the temperature data in the battery compartment collected by the thermistor, and the voltage data of the lithium battery collected by its own analog-to-digital converter, and judge the battery status of the lithium battery based on the deformation data, the temperature data and the voltage data.

[0007] Optionally, a rubber block is encapsulated between the lithium battery and the contact surface of the battery compartment;

[0008] The working strain gauge and the thermistor are both sealed in the rubber block.

[0009] Optionally, the system further comprises: a compensating strain gauge disposed on a non-contact surface between the lithium battery and the battery compartment;

[0010] The compensating strain gauge is used for performing temperature compensation when the working strain gauge is working.

[0011] Optionally, a Wheatstone bridge is used between the working strain gauge and the compensating strain gauge to amplify the collected data and output the deformation data;

[0012] After receiving the deformation data, the controller samples the deformation data using its own analog-to-digital converter.

[0013] The present application also provides a battery status monitoring method, which is applied to a controller in a battery status monitoring system in any one of the above embodiments, and the method includes:

[0014] Obtaining deformation data, voltage data of the lithium battery and temperature data in the battery compartment collected within a preset period of time;

[0015] When the deformation data of the lithium battery collected within the preset time period continuously exceeds the first preset deformation threshold for a number of times reaching a preset number threshold, judging whether the lithium battery is in a charge and discharge state according to the voltage data of the lithium battery collected within the preset time period;

[0016] If so, determine whether the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, and determine the battery state of the lithium battery according to the first determination result; wherein the second preset deformation threshold is higher than the first preset deformation threshold;

[0017] If not, it is determined whether the temperature data in the battery compartment exceeds a preset high temperature threshold, and the battery state of the lithium battery is determined according to the second judgment result.

[0018] Optionally, judging whether the lithium battery is in a charging or discharging state according to the voltage data of the lithium battery collected within the preset time period includes:

[0019] Determining a change trend of the voltage data of the lithium battery collected within the preset time period;

[0020] If the change trend is a downward trend, it is determined that the lithium battery is in a discharging state;

[0021] If the change trend is an upward trend, it is judged that the lithium battery is in a charging state;

[0022] If the change trend is no change, it is determined that the lithium battery is in a standby state.

[0023] Optionally, determining the battery state of the lithium battery according to the first judgment result includes:

[0024] If the first judgment result is that the deformation data exceeding the first preset deformation threshold value exceeds the second preset deformation threshold value, it is determined that the battery state of the lithium battery is an abnormal swelling state;

[0025] If the first judgment result is that the deformation data exceeding the first preset deformation threshold does not exceed the second preset deformation threshold, it is determined that the battery state of the lithium battery is a normal swelling state.

[0026] Optionally, determining the battery state of the lithium battery according to the second judgment result includes:

[0027] If the temperature data in the battery compartment exceeds the preset high temperature threshold, it is determined whether the deformation data exceeding the first preset deformation threshold exceeds a third preset deformation threshold, and the battery state of the lithium battery is determined according to the third determination result; wherein the third preset deformation threshold is higher than the first preset deformation threshold;

[0028] If the temperature data in the battery compartment does not exceed the preset high temperature threshold, initial deformation data of the lithium battery after installation is obtained, and the battery state of the lithium battery is determined based on the initial deformation data.

[0029] Optionally, determining the battery state of the lithium battery according to the third judgment result includes:

[0030] If the third judgment result is that the deformation data exceeding the first preset deformation threshold value exceeds the third preset deformation threshold value, it is determined that the battery state of the lithium battery is an abnormal swelling state;

[0031] If the third judgment result is that the deformation data exceeding the first preset deformation threshold does not exceed the third preset deformation threshold, it is determined that the battery state of the lithium battery is a normal swelling state.

[0032] Optionally, determining the battery state of the lithium battery according to the initial deformation data includes:

[0033] Determining a collection temperature when collecting the initial deformation data;

[0034] Comparing the collected temperature with the temperature data in the battery compartment to determine a temperature difference and a first deformation difference corresponding to the temperature difference;

[0035] Comparing the deformation data of the lithium battery with the initial deformation data to determine a second deformation difference;

[0036] Determining whether a difference between the first deformation difference and the second deformation difference exceeds a preset deformation difference threshold;

[0037] If it exceeds, it is determined that the battery state of the lithium battery is in an abnormal swelling state;

[0038] If it does not exceed, it is determined that the battery state of the lithium battery is a normal swelling state.

[0039] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0040] The present application provides a battery status monitoring system and a monitoring method, the system comprising a working strain gauge and a thermistor arranged between the contact surface of a lithium battery and a battery compartment, and a controller electrically connected to the lithium battery, the working strain gauge and the thermistor respectively; the working strain gauge is arranged between the contact surface of the lithium battery and the battery compartment, and can accurately measure the deformation data of the lithium battery when the battery compartment is subjected to force due to battery swelling, which is more effective than indirect measurement of current and other means; the thermistor can collect temperature data in the battery compartment, and the analog-to-digital converter of the controller can collect voltage data of the lithium battery. When the controller receives the deformation data, temperature data and voltage data, it can preliminarily determine whether the current lithium battery is in a swollen state through the deformation data, and combine the temperature data and the voltage data of the lithium battery to further determine whether the lithium battery is in a normal swelling state caused by high temperature or full charge or an abnormal swelling state caused by overcharge or over-discharge, thereby effectively improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0042] Figure 1 A schematic diagram of the structure of a battery status monitoring system provided in an embodiment of the present application;

[0043] Figure 2 A working principle diagram of a resistive strain gauge provided in an embodiment of the present application;

[0044] Figure 3 A schematic diagram of the structure of another battery status monitoring system provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of the connection structure of the working strain gauge and the compensation strain gauge provided in the embodiment of the present application;

[0046] Figure 5 A schematic diagram of the structure of a Wheatstone bridge provided in an embodiment of the present application;

[0047] Figure 6 A flowchart of a battery status monitoring method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] At present, the protection measures for lithium batteries in the market are mainly to integrate PPTC (recoverable fuse) inside the battery core or add temperature sensing devices on the surface of the battery to intervene. When the temperature of the battery core is too high or the current is too large, the PPTC will become a high-resistance state, thereby blocking the charging and discharging current of the lithium battery. The temperature sensing device can also notify the device to reduce the charging or discharging current when it detects that the temperature of the lithium battery is too high, so as to achieve the purpose of protecting the lithium battery. The above protection measures mainly protect the battery from the aspects of charging and discharging current and temperature. However, since lithium batteries will swell slightly during normal use, they may also swell in the case of overcharging and over-discharging. If the lithium battery is only protected by the charging and discharging current and temperature, it is impossible to effectively detect whether the swelling state of the lithium battery is abnormal.

[0050] Based on this, the present application proposes the following technical solutions, see below for details:

[0051] In one embodiment, Figure 1 As shown, Figure 1 A structural schematic diagram of a battery status monitoring system provided for an embodiment of the present application; the present application provides a battery status monitoring system, the system comprising: a working strain gauge and a thermistor arranged between the contact surface of a lithium battery and a battery compartment, and a controller electrically connected to the lithium battery, the working strain gauge, and the thermistor, respectively.

[0052] The controller is used to receive the deformation data of the lithium battery collected by the working strain gauge, the temperature data in the battery compartment collected by the thermistor, and the voltage data of the lithium battery collected by its own analog-to-digital converter, and judge the battery status of the lithium battery based on the deformation data, the temperature data and the voltage data.

[0053] In this embodiment, Figure 1As shown, the present application provides a working strain gauge and a thermistor between the contact surface of the lithium battery and the battery compartment. The working strain gauge is used to collect deformation data of the lithium battery when the battery compartment is subjected to force due to battery swelling, and send the deformation data to the controller; while the thermistor can change its resistance value according to the change of temperature in the battery compartment, and the controller can measure the temperature data in the battery compartment through the change of its resistance value.

[0054] In addition, the controller in the present application is also connected to the lithium battery and collects the voltage data of the lithium battery through its own analog-to-digital converter. In this way, the controller can preliminarily determine whether the lithium battery is in a swollen state through the deformation data, and then further determine whether the current swelling state of the lithium battery is a normal swelling state or an abnormal swelling state through the temperature data and voltage data, thereby effectively improving the detection accuracy.

[0055] For example, when the controller determines that the currently collected deformation data is higher than the normal deformation data, it can preliminarily determine that the lithium battery is swollen. Then, the controller can determine whether the current lithium battery is in a high temperature or fully charged state based on the temperature data and voltage data. Since the lithium battery may swell slightly due to high temperature or full charge during normal operation, the lithium battery can swell slightly due to high temperature or full charge. Therefore, when the controller determines that the lithium battery is currently in a high temperature or fully charged state based on the temperature data and voltage data, the current deformation data can be compared with the deformation data in the high temperature or fully charged state. If the current deformation data does not match the deformation data in the high temperature or fully charged state, it indicates that the swelling state of the lithium battery is abnormal. At this time, the power supply of the abnormally swollen battery can be cut off and an alarm can be issued, and the faulty battery can be replaced to ensure the user's safe use of the battery. If they match, it indicates that the swelling state of the lithium battery is normal, and no alarm is required, and only continuous observation is required.

[0056] Among them, the working strain gauge of the present application can be a resistive strain gauge. The working strain gauge can achieve the purpose of measurement by being pasted on the surface of a material or component. When the measured structural object is deformed due to stress, the working strain gauge can sense the deformation synchronously. When the working strain gauge is deformed, its resistance value will also change accordingly. By measuring the change in the resistance value of the working strain gauge, the deformation size of the measured object can be measured.

[0057] Indicatively, Figure 2 As shown, Figure 2 A working principle diagram of a resistive strain gauge provided in an embodiment of the present application; Figure 2In the figure, the power supply voltage is 2V, the resistance value of the resistance strain gauge and the fixed resistor are both 120Ω. Under ideal conditions, the voltage value of Vo is: Vo = power supply voltage / 2, Vo = 1V; when the object under test undergoes a microstrain, the resistance strain gauge also undergoes a microstrain accordingly, and the resistance value also changes by one millionth, and the resistance value changes by ΔR = 0.000001*120 = 0.00012Ω. At this time, Vo = 0.9999995V (assuming a positive change). When the sensitivity coefficient of the resistance strain gauge is 2, the output of Vo changes by about 1uV before and after the deformation. It can be seen that the resistance strain gauge can measure the deformation of the object with high precision.

[0058] In this application, since the lithium battery is installed in the battery compartment, there is contact between the lithium battery and the battery compartment. If the lithium battery swells, it will inevitably squeeze the battery compartment. Therefore, in this application, one or more working strain gauges can be attached between the maximum contact surface of the lithium battery and the battery compartment, and the force change of the battery compartment can be measured by the working strain gauge, and the deformation data of the lithium battery can be determined based on the force change.

[0059] Furthermore, the controller selected for use in the present application is equipped with an analog-to-digital converter (ADC), and the ADC is used to collect voltage data of the lithium battery. When collecting voltage data, the voltage data can be continuously collected within a certain period of time, and then the average value of the voltage data collected within a certain period of time is taken as a valid value, and the valid value is used as the voltage data adopted by the final controller.

[0060] It is understandable that when the controller in this application collects voltage data through its own ADC, the battery voltage of the lithium battery can be reduced to the voltage range of the ADC after resistor voltage division, and then the collected voltage can be converted into a low impedance output to the ADC interface through a follower amplifier, and finally sampled through the ADC to obtain voltage data. The controller can continuously collect voltage data for a period of time through the ADC and cache it, and judge the current battery status of the lithium battery, such as charging, discharging or standby, by judging the change trend of the voltage data.

[0061] In the above embodiment, the system may include a working strain gauge and a thermistor arranged between the contact surface of the lithium battery and the battery compartment, and a controller electrically connected to the lithium battery, the working strain gauge, and the thermistor respectively; the working strain gauge is arranged between the contact surface of the lithium battery and the battery compartment, and can accurately measure the deformation data of the lithium battery when the battery compartment is subjected to force due to battery swelling, which is more effective than indirect measurement of current and other means; the thermistor can collect temperature data in the battery compartment, and the analog-to-digital converter of the controller can collect voltage data of the lithium battery. When the controller receives the deformation data, temperature data and voltage data, it can preliminarily determine whether the current lithium battery is in a swollen state through the deformation data, and combine the temperature data and the voltage data of the lithium battery to further determine whether the lithium battery is in a normal swelling state caused by high temperature or full charge or an abnormal swelling state caused by overcharging and over-discharging, thereby effectively improving the user experience.

[0062] In one embodiment, Figure 3 As shown, Figure 3 A schematic structural diagram of another battery status monitoring system provided in an embodiment of the present application; a rubber block is encapsulated between the contact surface between the lithium battery and the battery compartment; the working strain gauge and the thermistor are both sealed in the rubber block.

[0063] In this embodiment, when using the working strain gauge to collect the deformation data of the lithium battery, the contact surface between the lithium battery and the battery compartment will be uneven due to the pasting of the working strain gauge and the lead of the working strain gauge, and the swelling of the lithium battery may also squeeze the working strain gauge, causing damage to it. Therefore, the present application can pot a rubber block between the contact surface of the lithium battery and the battery compartment, and seal the working strain gauge in the rubber block, thereby forming effective protection.

[0064] Specifically, the present application can use sealing silicone rubber in conjunction with a curing mold to seal the contact area between the battery compartment and the lithium battery into a rectangular rubber block with a height of about 3 mm. The cured rubber block can completely seal the working strain gauge and leads, thereby preventing damage to the battery due to swelling and extrusion, and will not affect the working strain gauge's sensing of the extrusion stress of the lithium battery.

[0065] Furthermore, in order to measure the ambient temperature inside the battery compartment, the present application can simultaneously cure and seal a thermistor when sealing the working strain gauge. This can prevent the thermistor from being damaged by battery swelling and squeezing, and will not affect the thermistor's sensing of temperature changes in the battery compartment.

[0066] Indicatively, Figure 3As shown, the working strain gauge and thermistor in the present application are fixed in the middle position of the contact area between the lithium battery and the battery compartment, and the working strain gauge and thermistor are attached to the battery compartment, which not only plays a fixing role but also does not hinder the measurement of the two.

[0067] In one embodiment, the system may further include: a compensating strain gauge disposed on a non-contact surface between the lithium battery and the battery compartment; the compensating strain gauge is used to perform temperature compensation when the working strain gauge is working.

[0068] In this embodiment, since the use environment of lithium batteries is wide and complex, and the temperature changes greatly, deformation detection is easily affected by temperature, resulting in deviation in the detection results. Therefore, the present application pastes a compensating strain gauge on the non-contact surface of the lithium battery and the battery compartment, away from possible stress points, and the compensating strain gauge is used for temperature compensation of deformation measurement.

[0069] It should be noted that the compensating strain gauge and the working strain gauge in the present application are a group of strain gauges obtained by screening and matching through specific means. The temperature coefficients of the two strain gauges are highly consistent, and the error is controlled within a certain range, so that the deformation data can be measured more accurately.

[0070] Indicatively, Figure 4 As shown, Figure 4 This is a schematic diagram of the connection structure of the working strain gauge and the compensating strain gauge provided in the embodiment of the present application; it can be understood that since the two matched strain gauges only change in temperature under ideal conditions without stress, the working strain gauge and the compensating strain gauge will change in resistance under the influence of temperature. Figure 4 In the figure, the upper and lower strain gauges can be considered as two resistors, the power supply voltage is a constant voltage source, the power supply voltage is 2V, and the resistance values ​​of the two resistors are both 350Ω, 0 error, Vo = 1V. Due to the influence of temperature drift, both resistors become 351Ω, and Vo is still 1V; but if the resistance values ​​of the two resistors change greatly due to the influence of temperature drift, such as one is 349Ω and the other is 351Ω, then Vo will have an error of about 3mV with the initial value. Therefore, when the temperature coefficients of the two strain gauges are set to be highly consistent in this application, the output of Vo will not change significantly, thereby achieving the suppression of the change in the resistance value of the strain gauge due to temperature change, and then being able to more accurately measure the actual deformation of the object being measured.

[0071] In one embodiment, Figure 5 As shown, Figure 5A structural schematic diagram of a Wheatstone bridge provided in an embodiment of the present application; a Wheatstone bridge is used between the working strain gauge and the compensating strain gauge to amplify the collected data and output deformation data; after the controller receives the deformation data, it uses its own analog-to-digital converter to sample the deformation data.

[0072] In this embodiment, when the present application uses a compensating strain gauge to perform temperature compensation on the working strain gauge, since the circuit composed of two strain gauges has a single-ended voltage output voltage, it is difficult to extract a microvolt voltage from the single-ended voltage for amplification and sampling. Therefore, the present application can use a Wheatstone bridge between the working strain gauge and the compensating strain gauge to amplify the collected data and output deformation data. After the controller receives the deformation data, it can use its own analog-to-digital converter to sample the deformation data.

[0073] Indicatively, Figure 5 As shown, Figure 5 The circuit in the embodiment uses a Wheatstone bridge to convert the voltage output by the working strain gauge and the compensation strain gauge into a differential voltage output by the voltage output by the other two fixed resistors, wherein the other two fixed resistors are also obtained through matching screening, and the temperature coefficient error is controlled within a certain range. The present application converts the single-ended voltage into a differential signal through a Wheatstone bridge, which can improve the signal-to-noise ratio, suppress the common-mode signal, facilitate the subsequent amplification and collection, and improve the data collection accuracy.

[0074] The battery status monitoring method provided in an embodiment of the present application is described below. The battery status monitoring method described below and the battery status monitoring system described above can be referenced to each other.

[0075] In one embodiment, Figure 6 As shown, Figure 6 A flowchart of a battery status monitoring method provided in an embodiment of the present application; the present application also provides a battery status monitoring method, which is applied to a controller in a battery status monitoring system in any one of the above embodiments, and the method may include:

[0076] S110: Obtaining deformation data, voltage data of the lithium battery and temperature data in the battery compartment collected within a preset period of time.

[0077] In this step, when the controller monitors the battery status of the lithium battery, it can obtain the deformation data, voltage data and temperature data of the lithium battery collected within a preset period of time. Among them, the deformation data of the lithium battery can be collected by the working strain gauge set between the contact surface of the lithium battery and the battery compartment, the voltage data of the lithium battery can be collected by the analog-to-digital converter provided by the controller, and the temperature data of the battery compartment can be collected by the thermistor set between the contact surface of the lithium battery and the battery compartment. For specific circuit design, please refer to Figure 1 to Figure 5 The circuit structure shown in and the above description of the battery status monitoring system will not be repeated here.

[0078] S120: When the deformation data of the lithium battery collected within the preset time period continuously exceeds the first preset deformation threshold number of times reaching the preset number threshold, determine whether the lithium battery is in a charging and discharging state according to the voltage data of the lithium battery collected within the preset time period; if so, execute S130, if not, execute S140.

[0079] In this step, after acquiring the deformation data, voltage data of the lithium battery collected within the preset time period and the temperature data in the battery compartment through S110, the present application can determine whether the number of times that the deformation data of the lithium battery collected within the preset time period continuously exceeds the first preset deformation threshold reaches the preset number threshold. If reached, it is further determined whether the lithium battery is in a charging and discharging state based on the voltage data of the lithium battery collected within the preset time period, and other actions are taken based on the judgment result.

[0080] It is understandable that after the present application obtains deformation data, voltage data and temperature data, it can first preliminarily determine whether the current lithium battery is swollen by the deformation data. And in the preliminary judgment process, in order to prevent misjudgment, the present application can collect deformation data of the lithium battery multiple times within a preset time period, and determine whether the number of times the deformation data of the lithium battery collected within the preset time period continuously exceeds the first preset deformation threshold reaches the preset number threshold. If it reaches, it indicates that the current lithium battery swelling state is a continuous state, not an occasional state, and then it can be determined that the battery state of the current lithium battery is a swelling state.

[0081] Among them, the first preset deformation threshold of the present application can be set according to the empirical data obtained in the preliminary test stage. In addition, due to the differences in battery types, packaging methods and battery compartment materials, the first preset deformation threshold will also be different; the preset number threshold of the present application can also be set according to the empirical data obtained in the preliminary test stage. For example, it can be set to 600 times, 800 times, etc., depending on the actual situation, and there is no limitation here.

[0082] S130: Determine whether the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, and determine the battery state of the lithium battery according to the first determination result.

[0083] In this step, when the controller determines that the lithium battery is in a charging and discharging state based on the voltage data of the lithium battery collected within a preset time period, the controller can continue to determine whether the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, and determine the battery state of the lithium battery based on the first judgment result.

[0084] It is understandable that lithium batteries will also have slight swelling during normal charging and discharging processes. When the present application monitors that the lithium battery is in a charging and discharging state, in order to avoid misjudgment, the present application can compare the deformation data exceeding the first preset deformation threshold with the second preset deformation threshold to obtain a first judgment result, and determine the battery status of the lithium battery based on the first judgment result.

[0085] Among them, in the present application, the second preset deformation threshold is set to be higher than the first preset deformation threshold. When the deformation data of the lithium battery exceeds the first preset deformation threshold, it indicates that the current deformation data of the lithium battery exceeds the minimum standard. When the deformation data of the lithium battery in the charging and discharging state exceeds the second preset deformation threshold, it indicates that the lithium battery is in an abnormal swelling state. Otherwise, it indicates that the lithium battery is in a normal swelling state, thereby determining the battery state of the lithium battery.

[0086] S140: Determine whether the temperature data in the battery compartment exceeds a preset high temperature threshold, and determine the battery state of the lithium battery according to the second determination result.

[0087] In this step, when the controller determines that the lithium battery is not in a charging or discharging state based on the voltage data of the lithium battery collected within a preset time period, in order to eliminate the impact of the lithium battery being in a swollen state due to high temperature, the controller can continue to check whether the temperature data in the battery compartment exceeds a preset high temperature threshold and obtain a second judgment result. Then the controller can determine the battery status of the lithium battery based on the second judgment result.

[0088] In one embodiment, judging whether the lithium battery is in a charging or discharging state according to the voltage data of the lithium battery collected within the preset time period in S120 may include:

[0089] S121: Determine a change trend of the voltage data of the lithium battery collected within the preset time period.

[0090] S122: If the change trend is a downward trend, it is determined that the lithium battery is in a discharging state.

[0091] S123: If the change trend is an upward trend, it is determined that the lithium battery is in a charging state.

[0092] S124: If the change trend is no change, it is determined that the lithium battery is in a standby state.

[0093] In this embodiment, when the controller determines whether the lithium battery is in a charging and discharging state based on the voltage data of the lithium battery collected within a preset time period, it can first determine the change trend of the voltage data of the lithium battery within the preset time period, and then determine whether the lithium battery is in a charging and discharging state based on the change trend.

[0094] For example, when the changing trend of the voltage data of the lithium battery in this application is a downward trend, it indicates that the lithium battery is in a discharging state; when the changing trend of the voltage data of the lithium battery is an upward trend, it indicates that the lithium battery is in a charging state; and when the changing trend of the voltage data of the lithium battery is no change, it indicates that the lithium battery is in a standby state.

[0095] It is understandable that, generally speaking, when a lithium battery is in a charging state, its battery voltage will gradually rise and reach a set voltage value, while when a lithium battery is in a discharging state, its battery voltage will gradually decrease and reach a certain value. When a lithium battery is in a normal standby state, its battery voltage can be considered to be almost unchanged.

[0096] In one embodiment, determining the battery state of the lithium battery according to the first judgment result in S130 may include:

[0097] S131: If the first judgment result is that the deformation data exceeding the first preset deformation threshold value exceeds the second preset deformation threshold value, it is determined that the battery state of the lithium battery is an abnormal swelling state.

[0098] S132: If the first judgment result is that the deformation data exceeding the first preset deformation threshold does not exceed the second preset deformation threshold, it is determined that the battery state of the lithium battery is a normal swelling state.

[0099] In this embodiment, the first judgment result may include deformation data exceeding the first preset deformation threshold exceeding the second preset deformation threshold, and deformation data exceeding the first preset deformation threshold not exceeding the second preset deformation threshold. When the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, it indicates that the lithium battery is in an abnormal swelling state; otherwise, it indicates that the lithium battery is in a normal swelling state, thereby determining the battery state of the lithium battery.

[0100] In one embodiment, determining the battery state of the lithium battery according to the second judgment result in S140 may include:

[0101] S141: If the temperature data in the battery compartment exceeds the preset high temperature threshold, determine whether the deformation data exceeding the first preset deformation threshold exceeds the third preset deformation threshold, and determine the battery state of the lithium battery according to the third judgment result; wherein the third preset deformation threshold is higher than the first preset deformation threshold.

[0102] S142: If the temperature data in the battery compartment does not exceed the preset high temperature threshold, initial deformation data of the lithium battery after installation is obtained, and the battery state of the lithium battery is determined based on the initial deformation data.

[0103] In this embodiment, the second judgment result may include two results: the temperature data in the battery compartment exceeds the preset high temperature threshold, and the temperature data in the battery compartment does not exceed the preset high temperature threshold. When the temperature data in the battery compartment exceeds the preset high temperature threshold, it indicates that the temperature in the current battery compartment is too high, and the lithium battery will also swell slightly under normal working conditions. Therefore, for this situation, the present application can continue to judge whether the deformation data exceeding the first preset deformation threshold exceeds the third preset deformation threshold, and obtain the third judgment result. Then, the present application can determine the battery state of the lithium battery according to the third judgment result. When the temperature data in the battery compartment does not exceed the preset high temperature threshold, the initial deformation data of the lithium battery after installation can be obtained, and the battery state of the lithium battery can be judged according to the initial deformation data.

[0104] It is understandable that lithium batteries will also have slight swelling phenomenon under high temperature conditions. When the present application monitors that the temperature data in the battery compartment exceeds the preset high temperature threshold, in order to avoid misjudgment, the present application can compare the deformation data exceeding the first preset deformation threshold with the third preset deformation threshold to obtain a third judgment result, and determine the battery status of the lithium battery based on the third judgment result.

[0105] Among them, in the present application, the third preset deformation threshold is set to be higher than the first preset deformation threshold. When the deformation data of the lithium battery exceeds the first preset deformation threshold, it indicates that the current deformation data of the lithium battery exceeds the minimum standard. When the deformation data of the lithium battery under high temperature exceeds the third preset deformation threshold, it indicates that the lithium battery is in an abnormally swollen state. Otherwise, it indicates that the lithium battery is in a normal swollen state, thereby determining the battery state of the lithium battery.

[0106] Furthermore, the initial deformation data after the lithium battery is installed in this application refers to the zero-point data collected after the lithium battery is installed. Since the lithium battery is in contact with the battery compartment after installation, there must be force between the two. Therefore, this application can record the initial deformation data and use it to compare with the data collected later, and then judge the battery status of the lithium battery based on the comparison results between the two.

[0107] In one embodiment, determining the battery state of the lithium battery according to the third judgment result in S141 may include:

[0108] S1411: If the third judgment result is that the deformation data exceeding the first preset deformation threshold exceeds the third preset deformation threshold, it is determined that the battery state of the lithium battery is an abnormal swelling state.

[0109] S1412: If the third judgment result is that the deformation data exceeding the first preset deformation threshold does not exceed the third preset deformation threshold, it is determined that the battery state of the lithium battery is a normal swelling state.

[0110] In this embodiment, the third judgment result may include two situations: the deformation data exceeding the first preset deformation threshold exceeds the third preset deformation threshold, and the deformation data exceeding the first preset deformation threshold does not exceed the third preset deformation threshold. When the deformation data exceeding the first preset deformation threshold exceeds the third preset deformation threshold, it indicates that the battery state of the lithium battery is an abnormal swelling state. For this state, the controller can issue an alarm and cut off the power supply of the lithium battery to ensure safety; and when the deformation data exceeding the first preset deformation threshold does not exceed the third preset deformation threshold, it indicates that the battery state of the lithium battery is a normal swelling state.

[0111] In one embodiment, determining the battery state of the lithium battery according to the initial deformation data in S142 may include:

[0112] S1421: Determine the collection temperature when collecting the initial deformation data.

[0113] S1422: Compare the collected temperature with the temperature data in the battery compartment to determine a temperature difference and a first deformation difference corresponding to the temperature difference.

[0114] S1423: Compare the deformation data of the lithium battery with the initial deformation data to determine a second deformation difference.

[0115] S1424: Determine whether the difference between the first deformation difference and the second deformation difference exceeds a preset deformation difference threshold.

[0116] S1425: If exceeded, it is determined that the battery state of the lithium battery is an abnormal swelling state.

[0117] S1426: If not, determining that the battery state of the lithium battery is a normal swelling state.

[0118] In this embodiment, when determining the battery state of the lithium battery based on the initial deformation data, the present application can first determine the collection temperature when the initial deformation data is collected, and then compare the collection temperature with the current temperature data in the battery compartment, and then determine the temperature difference between the two and the first deformation difference under the temperature difference, and then compare the deformation data of the lithium battery with the initial deformation data to determine the second deformation difference, and finally judge the battery state of the lithium battery based on whether the difference between the first deformation difference and the second deformation difference exceeds the preset deformation difference threshold.

[0119] It can be understood that the first deformation difference here refers to the difference between the initial deformation data and the standard deformation data corresponding to the temperature difference, and the second deformation difference refers to the difference between the initial deformation data and the current deformation data. The difference between the first deformation difference and the second deformation difference can be used to judge the current battery state of the lithium battery.

[0120] For example, the temperature when the initial deformation data is collected is 25°C. In a non-high temperature state, assuming that the current operating temperature is 10°C, the temperature drift of the monitoring system is 2ppm / °C, and the temperature difference is 15°C. At this time, the first deformation difference is about 30. If the calculated second deformation difference data greatly exceeds the deviation caused by temperature, it is abnormal. As described in the present application, when the difference between the first deformation difference and the second deformation difference exceeds the preset deformation difference threshold, the battery state of the lithium battery is determined to be an abnormal bulging state, and when the difference between the first deformation difference and the second deformation difference does not exceed the preset deformation difference threshold, the battery state of the lithium battery is determined to be a normal bulging state.

[0121] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0122] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can refer to each other.

[0123] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery status monitoring system, characterized in that: The system comprises: a working strain gauge and a thermistor arranged between the contact surface of the lithium battery and the battery compartment, and a controller electrically connected to the lithium battery, the working strain gauge and the thermistor respectively; The controller is used to receive the deformation data of the lithium battery collected within a preset time period by the working strain gauge, the temperature data in the battery compartment collected by the thermistor, and the voltage data of the lithium battery collected by the built-in analog-to-digital converter. When the deformation data of the lithium battery collected within the preset time period continuously exceeds the first preset deformation threshold and reaches a preset number threshold, it is judged whether the lithium battery is in a charging and discharging state according to the voltage data of the lithium battery collected within the preset time period; if so, it is judged whether the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, and the battery state of the lithium battery is determined according to the first judgment result; wherein the second preset deformation threshold is higher than the first preset deformation threshold; if not, it is judged whether the temperature data in the battery compartment exceeds the preset high temperature threshold, and the battery state of the lithium battery is determined according to the second judgment result.

2. The battery status monitoring system according to claim 1, characterized in that: A rubber block is encapsulated between the contact surface of the lithium battery and the battery compartment; The working strain gauge and the thermistor are both sealed in the rubber block.

3. The battery status monitoring system according to claim 1, characterized in that: The system further comprises: a compensating strain gauge disposed on a non-contact surface between the lithium battery and the battery compartment; The compensating strain gauge is used for performing temperature compensation when the working strain gauge is working.

4. The battery status monitoring system according to claim 3, characterized in that: A Wheatstone bridge is used between the working strain gauge and the compensating strain gauge to amplify the collected data and output deformation data; After receiving the deformation data, the controller samples the deformation data using its own analog-to-digital converter.

5. A battery status monitoring method, applied to a controller in a battery status monitoring system according to any one of claims 1 to 4, characterized in that: The method comprises: Obtaining deformation data, voltage data of the lithium battery and temperature data in the battery compartment collected within a preset period of time; When the deformation data of the lithium battery collected within the preset time period continuously exceeds the first preset deformation threshold for a number of times reaching a preset number threshold, judging whether the lithium battery is in a charge and discharge state according to the voltage data of the lithium battery collected within the preset time period; If so, determine whether the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, and determine the battery state of the lithium battery according to the first determination result; wherein the second preset deformation threshold is higher than the first preset deformation threshold; If not, it is determined whether the temperature data in the battery compartment exceeds a preset high temperature threshold, and the battery state of the lithium battery is determined according to the second judgment result.

6. The battery status monitoring method according to claim 5, characterized in that: The determining whether the lithium battery is in a charging or discharging state according to the voltage data of the lithium battery collected within the preset time period includes: Determining a change trend of the voltage data of the lithium battery collected within the preset time period; If the change trend is a downward trend, it is determined that the lithium battery is in a discharging state; If the change trend is an upward trend, it is judged that the lithium battery is in a charging state; If the change trend is no change, it is determined that the lithium battery is in a standby state.

7. The battery status monitoring method according to claim 5, characterized in that: Determining the battery state of the lithium battery according to the first judgment result includes: If the first judgment result is that the deformation data exceeding the first preset deformation threshold value exceeds the second preset deformation threshold value, it is determined that the battery state of the lithium battery is an abnormal swelling state; If the first judgment result is that the deformation data exceeding the first preset deformation threshold does not exceed the second preset deformation threshold, it is determined that the battery state of the lithium battery is a normal swelling state.

8. The battery status monitoring method according to claim 5, characterized in that: Determining the battery state of the lithium battery according to the second judgment result includes: If the temperature data in the battery compartment exceeds the preset high temperature threshold, it is determined whether the deformation data exceeding the first preset deformation threshold exceeds a third preset deformation threshold, and the battery state of the lithium battery is determined according to the third determination result; wherein the third preset deformation threshold is higher than the first preset deformation threshold; If the temperature data in the battery compartment does not exceed the preset high temperature threshold, initial deformation data of the lithium battery after installation is obtained, and the battery state of the lithium battery is determined based on the initial deformation data.

9. The battery status monitoring method according to claim 8, characterized in that: Determining the battery state of the lithium battery according to the third judgment result includes: If the third judgment result is that the deformation data exceeding the first preset deformation threshold value exceeds the third preset deformation threshold value, it is determined that the battery state of the lithium battery is an abnormal swelling state; If the third judgment result is that the deformation data exceeding the first preset deformation threshold does not exceed the third preset deformation threshold, it is determined that the battery state of the lithium battery is a normal swelling state.

10. The battery status monitoring method according to claim 8, characterized in that: Determining the battery state of the lithium battery according to the initial deformation data includes: Determining a collection temperature when collecting the initial deformation data; Comparing the collected temperature with the temperature data in the battery compartment to determine a temperature difference and a first deformation difference corresponding to the temperature difference; Comparing the deformation data of the lithium battery with the initial deformation data to determine a second deformation difference; Determining whether a difference between the first deformation difference and the second deformation difference exceeds a preset deformation difference threshold; If it exceeds, it is determined that the battery state of the lithium battery is in an abnormal swelling state; If it does not exceed, it is determined that the battery state of the lithium battery is a normal swelling state.

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