CN115128459A - A battery state monitoring system and monitoring method - Google Patents

Abstract

The present application provides a battery state monitoring system and monitoring method. The system includes a working strain gauge and a thermistor arranged between the contact surface of the lithium battery and the battery compartment, and a working strain gauge and a thermistor respectively connected to the lithium battery, the working strain gauge, and the thermistor. Electrically connected controller; the working strain gauge is set between the contact surface of the lithium battery and the battery compartment, which can accurately measure the deformation data of the lithium battery when the battery compartment is stressed due to battery bulging; the thermistor can collect the temperature data in the battery compartment , the analog-to-digital converter that comes with the controller can collect the voltage data of the lithium battery. When the controller receives the deformation data, temperature data and voltage data, it can preliminarily judge whether the current lithium battery is in a bulging state through the deformation data, and combine with The temperature data and the voltage data of the lithium battery can further determine whether the lithium battery is in a normal bulging state caused by high temperature or full power or an abnormal bulging state caused by overcharge and overdischarge, thereby effectively improving the user experience.

Description

A battery state monitoring system and monitoring method

technical field

The present application relates to the technical field of lithium batteries, and in particular, to a battery state monitoring system and a monitoring method.

Background technique

Lithium batteries have the advantages of light weight and high energy density, and have been widely used in many fields. However, during the use of lithium batteries, abnormal conditions such as high temperature and battery bulging will inevitably occur. If they cannot be found in time, there may even be serious consequences such as spontaneous combustion and explosion of the battery. For example, overcharging of a lithium battery will cause all the lithium atoms in the positive electrode material to be transferred to the negative electrode material, causing the original 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 the occurrence of lithium batteries. Bulging phenomenon.

At present, the protection measures for lithium batteries on the market mainly intervene by integrating PPTC (recoverable insurance device) inside the battery cell or adding a temperature sensing device on the surface of the battery. When the temperature of the battery cell is too high or the current is too large, the PPTC will It becomes 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 are mainly to protect the battery from the current and temperature of charging and discharging. However, because the lithium battery will bulge slightly during normal use, it may also bulge in the case of overcharge and overdischarge. Only by protecting the lithium battery by charging and discharging current and temperature, it is impossible to effectively detect whether the expansion state of the lithium battery is abnormal.

SUMMARY OF THE INVENTION

The purpose of this application is to solve at least one of the above technical defects, especially the technical defect in the prior art that it is impossible to effectively detect whether the expansion state of the lithium battery is abnormal.

The present application provides a battery state monitoring system, the system includes: a working strain gauge and a thermistor arranged between the contact surface of the lithium battery and the battery compartment, and a working strain gauge and a thermistor respectively connected to the lithium battery, the working strain gauge, a controller to which the thermistor is electrically connected;

The controller is configured 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 data collected by the built-in analog-to-digital converter. voltage data of the lithium battery, and determine the battery state of the lithium battery according to the deformation data, the temperature data and the voltage data.

Optionally, a rubber block is potted between the lithium battery and the contact surface of the battery compartment;

Both the working strain gauge and the thermistor are sealed within the rubber block.

Optionally, the system further includes: a compensation strain gauge disposed on the non-contact surface of the lithium battery and the battery compartment;

The compensation strain gauge is used for temperature compensation when the working strain gauge is in operation.

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

After receiving the deformation data, the controller samples the deformation data by using a built-in analog-to-digital converter.

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

Obtain the deformation data, voltage data and temperature data in the battery compartment of the lithium battery collected within a preset period;

When 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 of times threshold, the lithium battery is determined according to the voltage data of the lithium battery collected within the preset time period Whether it is in charge and discharge state;

If so, judge 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 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 a preset high temperature threshold, and the battery state of the lithium battery is determined according to the second judgment result.

Optionally, judging 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 includes:

determining the 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 discharge state;

If the change trend is an upward trend, it is determined 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.

Optionally, the 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 exceeds the second preset deformation threshold, then it is determined that the battery state of the lithium battery is an abnormally bulging state;

If the first determination 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 bulging state.

Optionally, the 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 lithium battery is determined according to the third judgment result. The battery state of the battery; 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, obtain initial deformation data of the lithium battery after installation, and determine the battery state of the lithium battery according to the initial deformation data.

Optionally, the 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 exceeds the third preset deformation threshold, it is determined that the battery state of the lithium battery is an abnormally bulging 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 bulging state.

Optionally, the 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 the second deformation difference;

determining whether the 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 an abnormally swollen state;

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

As can be seen from the above technical solutions, the embodiments of the present application have the following advantages:

The present application provides a battery state monitoring system and monitoring method. The system includes a working strain gauge and a thermistor arranged between the contact surface of the lithium battery and the battery compartment, and a working strain gauge and a thermistor respectively connected to the lithium battery, the working strain gauge, and the thermistor. Electrically connected controller; the working strain gauge is set between the contact surface of the lithium battery and the battery compartment, which can accurately measure the deformation data of the lithium battery when the battery compartment is stressed due to battery bulging, which is more effective than indirect measurement of current and other methods; The thermistor can collect the temperature data in the battery compartment, and the analog-to-digital converter that comes with the controller can collect the voltage data of the lithium battery. Determine whether the current lithium battery is in a bulging state, and combine the temperature data and the voltage data of the lithium battery to further determine whether the lithium battery is in a normal bulging state caused by high temperature or full power, or an abnormal bulging state caused by overcharge and overdischarge, etc. So as to effectively improve the user experience.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a battery state monitoring system provided by an embodiment of the present application;

FIG. 2 is a working principle diagram of the resistance strain gauge provided by the embodiment of the present application;

3 is a schematic structural diagram of another battery state monitoring system provided by an embodiment of the present application;

FIG. 4 is a schematic diagram of the connection structure of the working strain gauge and the compensation strain gauge provided by the embodiment of the application;

5 is a schematic structural diagram of a Wheatstone bridge according to an embodiment of the present application;

FIG. 6 is a schematic flowchart of a battery state monitoring method provided by an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

At present, the protection measures for lithium batteries on the market mainly intervene by integrating PPTC (recoverable insurance device) inside the battery cell or adding a temperature sensing device on the surface of the battery. When the temperature of the battery cell is too high or the current is too large, the PPTC will It becomes 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 are mainly to protect the battery from the current and temperature of charging and discharging. However, because the lithium battery will bulge slightly during normal use, it may also bulge in the case of overcharge and overdischarge. Only by protecting the lithium battery by charging and discharging current and temperature, it is impossible to effectively detect whether the expansion state of the lithium battery is abnormal.

Based on this, the application proposes the following technical solutions, see below for details:

In one embodiment, as shown in FIG. 1, FIG. 1 is a schematic structural diagram of a battery state monitoring system provided by an embodiment of the present application; the present application provides a battery state monitoring system, the system includes: A working strain gauge and a thermistor between the contact surface of the 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 configured 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 data collected by the built-in analog-to-digital converter. voltage data of the lithium battery, and determine the battery state of the lithium battery according to the deformation data, the temperature data and the voltage data.

In this embodiment, as shown in FIG. 1 , a working strain gauge and a thermistor are arranged between the contact surface of the lithium battery and the battery compartment, and the working strain gauge is used to collect the lithium battery when the battery compartment is stressed due to the bulging of the battery. The deformation data of the battery is sent to the controller; the thermistor can change its resistance value according to the temperature change in the battery compartment, and the controller can measure the battery compartment through the change of its resistance value. temperature data.

In addition, the controller in this application is also connected to the lithium battery, and collects the voltage data of the lithium battery through the built-in analog-to-digital converter, so that the controller can preliminarily judge whether the lithium battery is in a bulging state through the deformation data. , and then use the temperature data and voltage data to further determine whether the current bulging state of the lithium battery is a normal bulging state or an abnormal bulging state, thereby effectively improving the detection accuracy.

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 bulging, and then the controller can determine whether the current lithium battery is in a high temperature or fully charged state according to the temperature data and voltage data. , Due to the normal operation of the lithium battery, the lithium battery will also swell slightly due to high temperature or full power. Therefore, when the controller judges that the lithium battery is currently in a high temperature or fully charged state according to the temperature data and voltage data, it can compare the current deformation data with the deformation data in the high temperature or fully charged state. Or the deformation data in the fully charged state does not match, indicating that the bulging state of the lithium battery is abnormally bulging. At this time, the abnormally bulging battery can be cut off and the operation of alarming can be performed, as well as a prompt to replace the faulty battery to ensure the safe use of the battery by the user; If it matches, it means that the bulging state of the lithium battery is a normal bulging state, and there is no need for an alarm prompt, just continuous observation.

Among them, the working strain gauge of the present application can be a resistive strain gauge, and the working strain gauge can be pasted on the surface of a material or component to achieve the purpose of measurement. When the measured structural object is deformed by the action of stress, the working strain gauge can be synchronized. Feel the deformation. 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 of the measured object can be measured.

Schematically, as shown in FIG. 2, FIG. 2 is a working principle diagram of the resistance strain gauge provided by the embodiment of the application; in FIG. 2, the power supply voltage is 2V, and the resistance values of the resistance strain gauge and the fixed resistance are both 120Ω, Ideally, the voltage value of Vo is: Vo=supply voltage/2, Vo=1V; when a micro-strain occurs on the measured object, the resistive strain gauge also undergoes a corresponding micro-strain, and the resistance value also changes by millions 1/1, the resistance value of the change is ΔR=0.000001*120=0.00012Ω, at this time Vo=0.9999995V (assuming a positive change), when the sensitivity coefficient of the resistive strain gauge is 2, the output of Vo is at Change about 1uV before and after deformation. It can be seen that the resistance strain gauge can measure the deformation of the object with high precision.

In this application, since the lithium battery is installed in the battery compartment, and there is contact between the lithium battery and the battery compartment, if the lithium battery swells, the battery compartment is bound to be squeezed. Therefore, in this application, one or more working strain gauges can be pasted between the maximum contact surface of the lithium battery and the battery compartment, the force change of the battery compartment can be measured by the working strain gauge, and the force change of the lithium battery can be determined according to the force change. Deformation data.

Further, the controller selected in this application has its own analog-to-digital converter (ADC), and collects the voltage data of the lithium battery through the ADC. When collecting the voltage data, the voltage data within a certain period of time can be continuously collected, and then a certain period of time can be collected. The average value of the voltage data collected in the system is used as an effective value, and the effective value is used as the voltage data used by the final controller.

It can be understood that in this application, when the controller collects the voltage data through the built-in ADC, the battery voltage of the lithium battery can be reduced to the voltage range of the ADC after being divided by the resistor, and then the collected voltage can be changed into the voltage range of the ADC through the follower amplifier. The low-impedance output is output to the ADC interface, and finally the ADC is sampled to obtain voltage data. The controller can continuously collect and cache the voltage data for a period of time through the ADC, and judge the current battery status of the lithium battery by judging the trend of the voltage data, such as charging, discharging or standby.

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, working strain gauge and thermistor respectively; the working strain gauge Set between the contact surface of the lithium battery and the battery compartment, it can accurately measure the deformation data of the lithium battery when the battery compartment is stressed due to battery bulging, which is more effective than indirect measurement of current. Temperature data, the analog-to-digital converter of the controller can collect the voltage data of the lithium battery. When the controller receives the deformation data, temperature data and voltage data, it can preliminarily judge whether the current lithium battery is in a bulging state through the deformation data. Combined with the temperature data and the voltage data of the lithium battery, it is further judged whether the lithium battery is in a normal bulging state caused by high temperature or full power or an abnormal bulging state caused by overcharge and overdischarge, so as to effectively improve the user experience.

In one embodiment, as shown in FIG. 3 , which is a schematic structural diagram of another battery state monitoring system provided by an embodiment of the present application; a rubber block is potted between the lithium battery and the contact surface of the battery compartment ; Both the working strain gauge and the thermistor are sealed in the rubber block.

In this embodiment, in the process of 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 pasting the working strain gauge and the lead wire of the working strain gauge, and , the swelling of the lithium battery may also squeeze the working strain gauge, causing it to be damaged. Therefore, in the present application, a rubber block can be potted between the contact surface of the lithium battery and the battery compartment, and the working strain gauge can be sealed in the rubber block, thereby forming an effective protection.

Specifically, this application can use sealed silicone rubber to cooperate with a curing mold, and potting the contact area between the battery compartment and the lithium battery into a rectangular rubber block with a height of about 3mm. It is completely sealed, which can not only prevent the battery from being damaged by bulging and squeezing, but also will not affect the working strain gauge to sense the extrusion stress of the lithium battery.

Further, in order to measure the ambient temperature in the battery compartment, a thermistor can be cured and sealed at the same time when sealing the working strain gauge. The thermistor senses temperature changes inside the battery compartment.

Schematically, as shown in Figure 3, the working strain gage and thermistor in this application are fixed in the middle of the contact area between the lithium battery and the battery compartment, and the working strain gage and the thermistor are attached to the battery compartment. , which not only plays a fixed role, but also does not prevent the two from being measured.

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

In this embodiment, since the lithium battery is used in a wide range and complex environment, and the temperature changes greatly, the deformation detection is easily affected by the temperature, resulting in deviation of the detection result. Therefore, in the present application, a compensating strain gauge is pasted on the non-contact surface of the lithium battery and the battery compartment, and at the same time away from the possible force point position, and the compensating strain gauge is used for temperature compensation of deformation measurement.

It should be noted that the compensation strain gauge and the working strain gauge in this application are a set of strain gauges obtained after screening and matching by specific means. The temperature coefficients of the two strain gauges are highly consistent, and the error is controlled within a certain range, so that Deformation data can be measured more accurately.

Schematically, as shown in FIG. 4, FIG. 4 is a schematic diagram of the connection structure of the working strain gauge and the compensation strain gauge provided by the embodiment of the application; In the case of stress, only the temperature changes, and the resistance value of the working strain gage and the compensation strain gage will change under the influence of temperature. As shown in Figure 4, the upper and lower strain gauges can be considered as two resistors, the power supply voltage is a constant voltage source, and the power supply voltage is 2V. Assume that the resistance values of the two resistors are both 350Ω, 0 error, Vo=1V, due to the temperature drift Influence, the two resistors become 351Ω, and Vo is still 1V; but if the resistance of the two resistors changes greatly due to the influence of temperature drift, for example, when one is 349Ω and the other is 351Ω, then Vo will be There is an error of about 3mV from the initial value. Therefore, when the temperature coefficients of the two strain gauges are set to be highly consistent in the present application, the output of Vo will not change significantly, so that the resistance change of the strain gauge caused by the temperature change can be suppressed, and more accurate The actual deformation of the measured object is measured.

In one embodiment, as shown in FIG. 5 , FIG. 5 is a schematic structural diagram of a Wheatstone bridge provided by an embodiment of the application; a Wheatstone bridge pair is used between the working strain gauge and the compensation strain gauge The collected data is amplified, and the deformation data is output; after receiving the deformation data, the controller samples the deformation data by using the built-in analog-to-digital converter.

In this embodiment, when the application uses a compensation strain gage to perform temperature compensation when working on the working strain gage, due to the circuit composed of two strain gages, the output voltage is a single-ended voltage, and a microvolt-level voltage is extracted from the single-ended voltage. Amplification and sampling are difficult to achieve. Therefore, in the present application, a Wheatstone bridge can be used between the working strain gage and the compensation strain gage to amplify the collected data and output the deformation data. After the controller receives the deformation data, it can use the built-in analog-to-digital converter. Sample the deformation data.

Schematically, as shown in Figure 5, the circuit in Figure 5 uses a Wheatstone bridge to form a differential voltage output between the voltage output by the working strain gage and the compensation strain gage and the voltage output by the other two fixed resistors. The fixed resistors are also obtained through matching and screening, and the temperature coefficient error is guaranteed to be controlled within a certain range. In this application, the single-ended voltage is converted into a differential signal through a Wheatstone bridge, which can improve the signal-to-noise ratio, suppress common-mode signals, facilitate subsequent amplification and acquisition, and improve data acquisition accuracy.

The battery state monitoring method provided by the embodiments of the present application will be described below, and the battery state monitoring method described below and the battery state monitoring system described above may refer to each other correspondingly.

In one embodiment, as shown in FIG. 6 , FIG. 6 is a schematic flowchart of a battery state monitoring method provided by an embodiment of the present application; the present application also provides a battery state monitoring method, which is applied to any of the foregoing embodiments. A controller in the battery state monitoring system, the method may include:

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

In this step, when monitoring the battery state of the lithium battery, the controller may acquire deformation data, voltage data and temperature data in the battery compartment 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 arranged between the contact surface of the lithium battery and the battery compartment, and the voltage data of the lithium battery can be collected by the analog-to-digital converter built in the controller. The temperature data of the battery can be collected by the thermistor arranged between the contact surface of the lithium battery and the battery compartment. For the specific circuit design, please refer to the circuit structure shown in Figure 1 to Figure 5 and the description of the battery state monitoring system above. I won't go into details here.

S120: When 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 of times threshold, determine whether the lithium battery is in charge and discharge state according to the voltage data of the lithium battery collected within the preset time period status; if yes, execute S130, if not, execute S140.

In this step, after obtaining the deformation data, voltage data and temperature data in the battery compartment of the lithium battery collected within the preset time period through S110, the application can determine that the deformation data of the lithium battery collected within the preset time period continuously exceeds the first Whether the number of preset deformation thresholds reaches the preset number of times threshold, and if so, further determines whether the lithium battery is in a state of charge and discharge according to the voltage data of the lithium battery collected within the preset time period, and performs other actions according to the judgment result.

It can be understood that, after the application obtains the deformation data, the voltage data and the temperature data, the deformation data can be used to preliminarily determine whether the current lithium battery is swollen. And in the preliminary judgment process, in order to prevent misjudgment, the present application can collect the deformation data of the lithium battery multiple times within a preset period of time, and determine that the deformation data of the lithium battery collected within the preset period of time continuously exceeds the first preset deformation threshold value. Whether the number of times reached the preset number of times threshold, if so, it indicates that the current state of the lithium battery bulging is a continuous state, not accidental, and then it can be determined that the current state of the lithium battery is a bulging state.

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 difference in battery type, packaging method and battery compartment material, the first preset deformation threshold will also be different; this The preset number of application thresholds can also be set according to the empirical data obtained in the preliminary test phase. For example, it can be set to 600 times, 800 times, etc., depending on the actual situation, which is not limited here.

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 judgment result.

In this step, when the controller determines that the lithium battery is in a charging and discharging state according to the voltage data of the lithium battery collected within a preset period, the controller may continue to determine whether the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation The threshold value is determined, and the battery state of the lithium battery is determined according to the first judgment result.

It is understandable that the lithium battery will also have a slight bulging phenomenon during the normal charging and discharging process, and when the application detects that the lithium battery is in the charging and discharging state, in order to avoid misjudgment, the application may The deformation data of a preset deformation threshold is compared with the second preset deformation threshold to obtain a first judgment result, and the battery state of the lithium battery is determined according to the first judgment result.

Wherein, in this application, the second preset deformation threshold is set to be higher than the first preset deformation threshold, and 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, and 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 abnormally bulging state; otherwise, it indicates that the lithium battery is in a normal bulging state, and thus the battery state of the lithium battery can be determined. .

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.

In this step, when the controller judges that the lithium battery is not in the charging and discharging state according to the voltage data of the lithium battery collected within the preset time period, in order to eliminate the influence of the bulging state of the lithium battery caused by the high temperature, the controller can continue the charging and discharging of the lithium battery in the battery compartment. Whether the temperature data exceeds the preset high temperature threshold, and obtain a second judgment result, then the controller can determine the battery state of the lithium battery according to the second judgment result.

In one embodiment, in S120, determining 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 may include:

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

S122: If the change trend is a downward trend, determine that the lithium battery is in a discharge state.

S123: If the change trend is an upward trend, determine that the lithium battery is in a charging state.

S124: If the change trend is no change, determine that the lithium battery is in a standby state.

In this embodiment, when judging whether the lithium battery is in the state of charge and discharge according to the voltage data of the lithium battery collected within the preset time period, the controller may first determine the change trend of the voltage data of the lithium battery within the preset time period, and then according to the Change trend to judge whether the lithium battery is in the state of charge and discharge.

For example, when the change 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 discharge state; when the change trend of the voltage data of the lithium battery is an upward trend, it indicates that the lithium battery is in a charged state, and when the lithium battery When the change trend of the voltage data of the battery is no change, it indicates that the lithium battery is in a standby state.

It can be understood that, in general, when a lithium battery is in a charged state, its battery voltage will gradually increase and reach the set voltage value, while when a lithium battery is in a discharged 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 almost unchanged.

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

S131: If the first determination result is that the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, determine that the battery state of the lithium battery is an abnormally bulging state.

S132: If the first determination result is that the deformation data exceeding the first preset deformation threshold does not exceed the second preset deformation threshold, determine that the battery state of the lithium battery is a normal bulging state.

In this embodiment, the first judgment result may include that the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, and the deformation data exceeding the first preset deformation threshold does not exceed the second preset deformation threshold, and 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 abnormally bulging state; otherwise, it indicates that the lithium battery is in a normal bulging state, and thus the battery state of the lithium battery can be determined .

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

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 a third preset deformation threshold, and determine the the battery state of the lithium battery; wherein, the third preset deformation threshold is higher than the first preset deformation threshold.

S142: If the temperature data in the battery compartment does not exceed the preset high temperature threshold, obtain initial deformation data of the lithium battery after installation, and determine the battery state of the lithium battery according to the initial deformation data.

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 When the high temperature threshold is set, it indicates that the current temperature in the battery compartment is too high, and the lithium battery will bulge slightly under normal working conditions. Therefore, in response to this situation, the application can continue to determine the deformation exceeding the first preset deformation threshold. Whether the data exceeds the third preset deformation threshold, and obtain a 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.

It can be understood that the lithium battery will also have a slight swelling phenomenon under high temperature, and when the application detects that the temperature data in the battery compartment exceeds the preset high temperature threshold, in order to avoid misjudgment, the application can The deformation data exceeding the first preset deformation threshold is compared with the third preset deformation threshold to obtain a third judgment result, and the battery state of the lithium battery is determined according to the third judgment result.

Wherein, in this 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, and When the deformation data of the lithium battery in a high temperature state exceeds the third preset deformation threshold, it indicates that the lithium battery is in an abnormally bulging state; otherwise, it indicates that the lithium battery is in a normal bulging state, and thus the battery state of the lithium battery can be determined.

Further, 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 there is contact between the lithium battery and the battery compartment after installation, there must be a strong force between the two. Therefore, this application can record the initial deformation data, and use this to compare the data collected later, and then based on the relationship between the two The comparison results are used to judge the battery status of the lithium battery.

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

S1411: If the third determination result is that the deformation data exceeding the first preset deformation threshold exceeds the third preset deformation threshold, determine that the battery state of the lithium battery is an abnormally bulging state.

S1412: If the third determination result is that the deformation data exceeding the first preset deformation threshold does not exceed the third preset deformation threshold, determine that the battery state of the lithium battery is a normal bulging state.

In this embodiment, the third judgment result may include that 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. In this case, 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 abnormally bulging. For this state, the controller can issue an alarm and cut off the power supply of the lithium battery , so as 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 bulging state.

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

S1421: Determine the acquisition temperature when acquiring the initial deformation data.

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

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

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

S1425: If it exceeds, determine that the battery state of the lithium battery is an abnormally swollen state.

S1426: If it does not exceed, determine that the battery state of the lithium battery is a normal swelling state.

In this embodiment, when determining the battery state of the lithium battery according to the initial deformation data, the present application can first determine the acquisition temperature when the initial deformation data is acquired, and then compare the acquisition temperature with the current temperature data in the battery compartment, 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 according to the first deformation difference and the first deformation difference. Whether the difference between the two deformation differences exceeds a preset deformation difference threshold is used to determine the battery state of the lithium battery.

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 determine the current battery state of the lithium battery.

For example, the temperature when collecting the initial deformation data is 25°C. In the non-high temperature state, assuming that the current working temperature is 10°C, the temperature drift of the monitoring system is 2ppm/°C, and the temperature difference is 15°C, the first deformation difference is about 30°C. , if the calculated second deformation difference data greatly exceeds the deviation caused by temperature, it is abnormal. As described in this application, when the difference between the first deformation difference and the second deformation difference exceeds a preset deformation difference threshold, it is determined that the battery state of the lithium battery is an abnormally bulging state, and when the first deformation difference and the second deformation difference are in a state of abnormal swelling When the difference between the deformation differences does not exceed the preset deformation difference threshold, it is determined that the battery state of the lithium battery is a normal bulging state.

Finally, it should also be noted that in this document, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply these entities or that there is any such actual relationship or sequence between operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

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 required, and the same and similar parts can be referred to each other. .

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, this application is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A battery state 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 working strain gauge and a thermistor arranged between the lithium battery and the working strain a controller to which the meter and the thermistor are electrically connected; The controller is configured 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 data collected by the built-in analog-to-digital converter. voltage data of the lithium battery, and determine the battery state of the lithium battery according to the deformation data, the temperature data and the voltage data. 2. The battery state monitoring system according to claim 1, wherein a rubber block is potted between the lithium battery and the contact surface of the battery compartment; Both the working strain gauge and the thermistor are sealed within the rubber block. 3 . The battery state monitoring system according to claim 1 , wherein the system further comprises: a compensation strain gauge disposed on the non-contact surface of the lithium battery and the battery compartment; 3 . The compensation strain gauge is used for temperature compensation when the working strain gauge is in operation. 4. The battery state monitoring system according to claim 3, wherein a Wheatstone bridge is used between the working strain gauge and the compensation strain gauge to amplify the collected data, and output deformation data; After receiving the deformation data, the controller samples the deformation data by using a built-in analog-to-digital converter. 5. A battery state monitoring method, applied to the controller in the battery state monitoring system according to any one of the preceding claims 1-4, wherein the method comprises: Obtain the deformation data, voltage data and temperature data in the battery compartment of the lithium battery collected within a preset period; When 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 of times threshold, the lithium battery is determined according to the voltage data of the lithium battery collected within the preset time period Whether it is in charge and discharge state; If so, judge 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 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 a preset high temperature threshold, and the battery state of the lithium battery is determined according to the second judgment result. 6 . The battery state monitoring method according to claim 5 , wherein the judging 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 comprises: 6 . determining the 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 discharge state; If the change trend is an upward trend, it is determined 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 state monitoring method according to claim 5, wherein the determining the battery state of the lithium battery according to the first judgment result comprises: If the first judgment result is that the deformation data exceeding the first preset deformation threshold exceeds the second preset deformation threshold, then it is determined that the battery state of the lithium battery is an abnormally bulging state; If the first determination 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 bulging state. 8. The battery state monitoring method according to claim 5, wherein the determining the battery state of the lithium battery according to the second judgment result comprises: 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 lithium battery is determined according to the third judgment result. The battery state of the battery; 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, obtain initial deformation data of the lithium battery after installation, and determine the battery state of the lithium battery according to the initial deformation data. 9 . The battery state monitoring method according to claim 8 , wherein the determining the battery state of the lithium battery according to the third judgment result comprises: 10 . 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 abnormally bulging 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 bulging state. 10 . The battery state monitoring method according to claim 8 , wherein the determining the battery state of the lithium battery according to the initial deformation data comprises: 10 . 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 the second deformation difference; determining whether the 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 an abnormally swollen 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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