Pressure monitoring and condensation risk monitoring method and system for battery box

Abstract

The invention belongs to the field of battery box pressure monitoring, and particularly relates to a battery box pressure monitoring and condensation risk monitoring method and system. Comprising the steps that the difference between the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box obtained by the same battery box at the same moment is obtained, and the difference obtained through difference serves as the pressure in the battery box of the battery box; if the condition that the pressure in the battery box is larger than the set air pressure threshold value is met, it is judged that the pressure in the battery box is abnormal; the air pressure threshold is set to be greater than 0. The method can ensure that the mechanical structure of the battery box is complete (that is, solid and liquid impurities in the external environment can be prevented from invading and damaging the battery in the box), and the effect of accurately and reliably monitoring the internal pressure of the battery box is realized as much as possible under the conditions that the battery box is not perforated and the protection level of the battery box is not influenced.

Description

Technical Field

[0001] The present invention belongs to the field of battery box pressure monitoring, and particularly relates to a method and system for monitoring the pressure of a battery box and the risk of condensation. Background Art

[0002] The development of new energy vehicles has shifted from policy-driven to market-driven, and will evolve around the three directions of "safer, smarter, and more sustainable" in the future. With the technological iteration and the improvement of the ecological system, new energy vehicles will gradually replace fuel vehicles and become the core carrier of the global transportation energy revolution, and reshape the automotive industry pattern and energy consumption mode.

[0003] For the new energy power batteries used in new energy vehicles, the battery box is an important device required to protect the new energy power batteries. Lithium-ion batteries may undergo thermal runaway under overcharge, over-discharge, short circuit or high-temperature environments, resulting in the decomposition of the internal electrolyte and the generation of a large amount of gas (such as CO, H2, etc.), causing a sudden increase in the internal pressure of the battery box. If the pressure cannot be released in time, it may cause the battery to bulge, rupture or even explode. Since the gas changes that may occur during the operation of the new energy power battery will change the internal pressure of the battery box, seriously affecting the safety and performance of the new energy power battery, the battery safety problems caused by this factor have become a key concern in the industry.

[0004] In summary, the current demand is to monitor the internal pressure of the battery box, that is, to monitor the air pressure change in real time, so as to identify early signals of thermal runaway (such as abnormal air pressure fluctuations) in advance, trigger a safety protection mechanism (such as cutting off the circuit, starting a pressure relief valve or activating a cooling system), and avoid a chain reaction. The battery box pressure monitoring technologies proposed in the current industry often require opening holes in the battery box to directly measure the internal pressure of the battery box (that is, the pressure monitoring device is usually installed on the box wall, and holes need to be opened in the battery box to enable the device to pass through the battery box for monitoring). However, such a method of achieving pressure monitoring by opening holes in the battery box is very likely to cause the risk of failure of the protection level of the battery box. If the protection level of the battery box fails, it may cause solid and liquid impurities in the external environment to invade, thereby damaging the batteries in the box (that is, causing short circuits, performance degradation and shortening of battery life, etc.). Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for monitoring the pressure of a battery box and the risk of condensation, which are used to solve the problem that the method of opening holes in the battery box to achieve battery box pressure monitoring in the prior art causes the failure of the protection level of the battery box, thereby damaging the batteries in the box.

[0006] To achieve the above-mentioned object, the present invention provides a method for monitoring pressure of a battery box, the method comprising: subtracting the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box, respectively obtained at the same time for the same battery box, and using the difference obtained as the internal pressure of the battery box; If the condition that the pressure inside the battery box is greater than a set pressure threshold is met, it is determined that the pressure inside the battery box is abnormal; the set pressure threshold is greater than 0.

[0007] Beneficial Effects: The present invention provides a novel battery box pressure monitoring method. This method simultaneously monitors the air pressure inside and outside the same battery box to calculate the internal pressure (i.e., relative pressure, which typically fluctuates around 0) at that moment. The method then determines whether the internal pressure of the battery box is abnormal based on whether the pressure meets a pressure abnormality condition. This condition is that the internal pressure of the battery box exceeds a set pressure threshold (a value greater than 0) after a first set period of time. This method effectively monitors both the internal and external environments of the battery box simultaneously, obtaining the air pressures of each environment. By subtracting these two pressures, a relative pressure is calculated, which represents the internal pressure of the battery box, rather than directly using existing air pressure detection devices dedicated to relative pressure measurement. (Using such devices typically requires ensuring that the pressure detection device is exposed to both the internal and external pressure environments to be measured, which requires mechanical damage to the battery box, such as openings.) Furthermore, by setting a reasonable pressure threshold as a metric, this method can detect whether the internal pressure of the battery compartment under test has increased by a certain value compared to the external pressure due to the heating of the batteries inside the compartment. If this is detected, the pressure inside the battery compartment is considered abnormal. This reasonable pressure threshold can minimize false positives when the pressure inside the battery compartment fluctuates within the normal range, resulting in more accurate judgments.

[0008] In summary, this method can ensure the mechanical integrity of the battery box (that is, it can prevent solid and liquid impurities in the external environment from invading and causing damage to the batteries in the box), and can achieve the effect of accurately and reliably monitoring the internal pressure of the battery box without opening holes in the battery box and affecting the protection level of the battery box.

[0009] Furthermore, the method further includes: if the pressure in the battery box is greater than the set pressure threshold and the pressure in the battery box is greater than the set pressure threshold and less than the thermal runaway alarm threshold, determining that the abnormal pressure in the battery box is in the early warning stage; and in this case, determining the relationship between the pressure in the battery box and the set pressure threshold and the thermal runaway alarm threshold; If the condition that the pressure in the battery box is greater than the thermal runaway alarm threshold is met, it is determined that the abnormal situation of the pressure in the battery box is: thermal runaway of the battery in the battery box; the thermal runaway alarm threshold is greater than the set air pressure threshold.

[0010] Further, the methods for obtaining the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box include: measuring the air pressure value of the internal environment of the battery box through the built-in air pressure sensor of the battery box; measuring the air pressure value of the internal and external environments of the battery box through the external air pressure sensor of the battery box; the external air pressure sensor and the built-in air pressure sensor have the same model.

[0011] The present invention also provides a pressure monitoring system for a battery box, including a processor, and the processor is used to execute a computer program to implement the steps of the above-mentioned pressure monitoring method for the battery box.

[0012] The pressure monitoring system of the battery box can achieve the same beneficial effects as the above-mentioned pressure monitoring method for the battery box.

[0013] The present invention also provides a method for monitoring the condensation risk of a battery box, and the method includes: subtracting the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box respectively obtained at the same moment for the same battery box, and using the obtained difference as the pressure inside the battery box of the battery box. On the basis that the duration of the situation where the pressure inside the battery box is less than 0 is greater than the second set duration, if the condition that the humidity of the external environment of the battery box on the same day is greater than the set humidity threshold is simultaneously met, it is determined that there is a condensation risk inside the battery box.

[0014] Beneficial effects: The present invention provides a brand-new method for monitoring the condensation risk of a battery box. This method monitors the air pressure values of the internal and external environments of the same battery box at the same moment, and calculates the internal pressure of the battery box at this moment (i.e., the relative pressure, and the value of the internal pressure of this battery box usually fluctuates around 0); then specifically determines whether there is a condensation risk in this battery box according to whether the internal pressure of this battery box and the humidity of the external environment meet the condensation risk conditions. The conditions are as follows: The duration when the internal pressure of the battery box is less than 0 lasts longer than the second set duration; the humidity of the external environment of the battery box on the same day is greater than the set humidity threshold. This method actually monitors the internal and external environments of the battery box simultaneously, and respectively obtains the air pressures of these two environments. By taking the difference between these two air pressures, a relative pressure is finally obtained, and this relative pressure represents the internal pressure of the battery box, rather than directly using the existing air pressure detection device dedicated to measuring relative pressure (if a dedicated air pressure detection device for measuring relative pressure is used, it is usually necessary to ensure that such an air pressure detection device is in contact with the internal pressure environment and the external pressure environment to be measured at the same time, and it is necessary to use means such as opening holes in the battery box, which will damage the mechanical structure of the battery box). At the same time, this method uses the internal pressure of the battery box being less than 0 as one of the conditions for measuring the condensation risk, and can judge whether there is a possibility that water vapor condenses due to too low temperature outside the battery box to be measured (because too low temperature outside the box will cause the external air pressure to be greater than the internal air pressure, so the internal environment air pressure - external environment air pressure will be less than 0; but at this time, it cannot be completely determined that there will be a condensation risk). On this basis, if the condition that the humidity of the external environment is greater than the set humidity threshold is simultaneously met (i.e., the humidity reaches a certain value), it can be determined that the external temperature is low and the humidity is high at this time, and the conditions for generating condensation are met, so it is determined that there is a condensation risk inside this battery box.

[0015] In summary, this method can ensure the integrity of the mechanical structure of the battery box (that is, it can prevent solid and liquid impurities in the external environment from invading and damaging the batteries inside the box), and without opening holes in the battery box and without affecting the protection level of the battery box, it can try to achieve the effect of monitoring whether there is a condensation risk inside the battery box.

[0016] Furthermore, the methods for obtaining the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box include: measuring the air pressure value of the internal environment of the battery box through the built-in air pressure sensor of this battery box; measuring the air pressure value of the internal and external environments of the battery box through the external air pressure sensor of this battery box; the external air pressure sensor and the built-in air pressure sensor have the same model.

[0017] The present invention also provides a condensation risk monitoring system for a battery box, including a processor, and the processor is used to execute a computer program to implement the steps of the above-mentioned method for monitoring the condensation risk of the battery box.

[0018] The dew condensation risk monitoring system of the battery box can achieve the same beneficial effects as the above-mentioned dew condensation risk monitoring method of the battery box. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flowchart of the pressure monitoring method of the battery box in the embodiment of the pressure monitoring method of the battery box of the present invention; Figure 2 It is an application example diagram of the pressure monitoring method of the battery box in the embodiment of the pressure monitoring method of the battery box of the present invention; Among them, 1 represents a single battery box in the vehicle; 2 represents the air pressure sensors respectively built in two different battery boxes in the vehicle; 2a represents the air pressure sensor built in battery box 1; 2b represents the air pressure sensor built in another battery box; 3 represents the air pressure sensor outside the two different battery boxes; 4 represents the controller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0021] Embodiment of the pressure monitoring method of the battery box This embodiment provides a technical solution for a pressure monitoring method of a battery box. This method only needs to obtain the respective air pressures in the internal and external environments of the battery box, and obtain the internal pressure of the battery box through the relative pressure obtained by taking the difference between them (instead of directly obtaining the internal pressure of the battery box through an existing air pressure detection device dedicated to measuring relative pressure). According to whether the internal pressure of the battery box meets the set judgment conditions, it is determined whether the pressure in the battery box is abnormal. Therefore, there is no need to use the actual pressure obtained by opening holes in the battery box as the criterion. Through this method, the pressure monitoring of the battery box can be realized without affecting the protection level of the battery box.

[0022] In this embodiment, the method includes: taking the difference between the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box respectively obtained for the same battery box at the same time, and using the obtained difference value as the internal pressure of the battery box. The methods for obtaining the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box include: measuring the air pressure value of the internal environment of the battery box through the air pressure sensor built in the battery box; measuring the air pressure value of the internal and external environments of the battery box through the air pressure sensor outside the battery box; the models of the external air pressure sensor and the internal air pressure sensor are the same.

[0023] Specifically, referring to Figure 1 , the calculation method of the internal pressure P1 of the battery box is: the internal pressure P1 of the battery box = the internal air pressure value P2 (that is, the air pressure value of the internal environment of the battery box) - the external air pressure value P3 (that is, the air pressure value of the external environment of the battery box). TakingFigure 2 Taking the battery box 1 in [reference] as an example, the method for obtaining the pressure P1 inside the battery box 1 is as follows: The vehicle controller issues an instruction to the controller 4 corresponding to the battery box 1, so as to control the built-in air pressure sensor 2a of the battery box 1 (that is, the air pressure sensor corresponding to the battery box 1 among all the air pressure sensors represented by 2) through the controller 4 to measure the air pressure value P2 inside its box; similarly, control the external air pressure sensor 3 of the battery box 1 to measure the air pressure value P3 outside its box; the difference between P2 and P3 is equivalent to the pressure inside the battery box 1. When setting the air pressure sensor, it is necessary to ensure that the air pressure sensors 2 (including 2a and 2b) and the air pressure sensor 3 have the same model, so as to ensure that the air pressure values measured by the air pressure sensors 2 and 3 can be accurately calculated, so as to obtain the correct pressure P1 inside the battery box. Among them, P2, P3 participating in the calculation, and the calculated P1 are all sent to the vehicle controller through the controller 4. After obtaining the pressure P1 inside the battery box, the controller 4 determines whether the pressure inside the battery box is abnormal according to the magnitude relationship between the pressure P1 inside the battery box and the set air pressure threshold. The determination method is as follows: If the condition that the pressure inside the battery box is greater than the set air pressure threshold (the set air pressure threshold is greater than 0) is met, it is determined that the pressure inside the battery box is abnormal. If the condition that the pressure inside the battery box is greater than the set air pressure threshold and less than the thermal runaway alarm threshold is met, the situation where the pressure inside the battery box is abnormal is determined as: the battery box is in the early warning stage; in this case, judge the magnitude relationship between the pressure inside the battery box, the set air pressure threshold, and the thermal runaway alarm threshold.

[0024] Taking the pressure monitoring of the battery box 1 as an example, as Figure 1As shown in the figure, first, it is judged whether the pressure P1 inside the battery box 1 of the battery box is a positive value (i.e., P1 > 0); if P1 meets the condition that P1 is a positive value, then it is judged whether the pressure P1 inside the battery box is greater than the set air pressure threshold Xpa. If the condition that the pressure P1 inside the battery box is less than the set air pressure threshold Xpa is met, the battery box pressure is normal. If P1 is greater than the set air pressure threshold Xpa, it is determined that the pressure P1 inside the battery box 1 of the battery box enters the warning range (i.e., the battery box is in the warning stage). This situation may be due to an internal battery failure, a relatively large change in the vehicle's relative altitude, or other unknown working conditions. At this time, it is necessary to closely monitor whether the pressure inside the battery box further increases, and further judge in combination with whether the battery voltage and temperature information collection is normal. If the frequency of P1 exceeding Xpa is relatively high, but it has not exceeded Ypa, and other information collections are normal, it may be caused by special working conditions, and the cause cannot be attributed to an internal battery failure; however, if other information collections also show abnormalities, there may indeed be relatively serious problems inside the battery at this time, and maintenance and troubleshooting are required. The pressure monitoring methods of other battery boxes in the vehicle are the same as that of the battery box 1. It should be noted that in this embodiment, the air pressure sensor 3 is used as the air pressure sensor outside all the battery boxes (in total). To monitor the pressure of which battery box, the air pressure value of the external environment of which battery box is collected through the air pressure sensor 3. In other embodiments, corresponding air pressure sensors can also be separately set for each battery box to collect the air pressure values of the external environments of each battery box respectively; or several battery boxes can be divided into a group, and one air pressure sensor is set for each group to collect the air pressure values of the external environments of the battery boxes in that group, that is, to monitor the pressure of which battery box in the group, the air pressure value of the external environment of which battery box is collected through the corresponding air pressure sensor of that group.

[0025] If the condition that the pressure inside the battery box is greater than the thermal runaway alarm threshold Ypa (the thermal runaway alarm threshold Ypa is greater than the set air pressure threshold Xpa) is met, it is determined that the abnormal situation of the pressure inside the battery box is: the battery inside the battery box undergoes thermal runaway.

[0026] In this embodiment, the thermal runaway alarm threshold is set to Ypa, and Ypa > Xpa. Taking the pressure P1 inside the battery box monitored by the battery box 1 at a certain moment as an example, on the premise that it is known that P1 > Xpa, if the pressure P1 inside the battery box of the battery box 1 is also greater than the thermal runaway alarm threshold Ypa (i.e., P1 > Ypa), it can be determined that the abnormal situation of the current pressure inside the battery box is: the battery thermal runaway inside the battery box 1. Thermal runaway is a relatively serious abnormal situation of the battery box, which may cause accidents such as battery bulging, rupture, and even explosion. Therefore, if such a situation occurs, it is necessary to trigger a thermal runaway alarm. In this embodiment, after determining the thermal runaway of the battery inside the battery box 1, the specific way to trigger the thermal runaway alarm is: to remind the vehicle to pull over to the side of the road and push a post-sales inspection. In other embodiments, the thermal runaway alarm can also be implemented in other ways, such as alarming through a buzzer to attract the driver's attention, and the driver can choose the handling method by himself. Embodiment of the pressure monitoring system of the battery box This embodiment provides a technical solution for a pressure monitoring system of a battery box. In this embodiment, the pressure monitoring method of the battery box in the embodiment of the pressure monitoring method of the battery box is adopted, and the pressure monitoring of the battery box can be realized.

[0027] Since the specific working mode and working principle of the pressure monitoring system of the battery box in this embodiment have been described in detail in the above embodiment of the pressure monitoring method of the battery box, they will not be elaborated here.

[0028] Embodiment of the condensation risk monitoring method of the battery box This embodiment provides a technical solution for a condensation risk monitoring method of a battery box. This method only needs to obtain the respective air pressures inside and outside the battery box environment respectively, and obtain the pressure inside the battery box through the relative pressure obtained by taking the difference between them (instead of directly obtaining the pressure inside the battery box through an existing air pressure detection device dedicated to measuring relative pressure). According to whether the pressure inside the battery box meets the set judgment conditions, a judgment is made on whether there is a condensation risk inside the battery box, and there is no need to use the actual pressure obtained by opening holes in the battery box as a criterion. Through this method, the condensation risk monitoring of the battery box can be realized without affecting the protection level of the battery box.

[0029] In this embodiment, the method includes: taking the difference between the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box respectively obtained for the same battery box at the same time, and using the obtained difference value as the pressure inside the battery box of the battery box.

[0030] In this embodiment, the method for calculating the pressure P1 inside the battery box is the same as that in the embodiment of the pressure monitoring method for the battery box. After obtaining the pressure P1 inside the battery box, the controller 4 determines whether there is a risk of condensation inside the battery box according to the relationship between the duration of the pressure P1 inside the battery box being less than 0 and the second set duration, and the relationship between the humidity of the external environment of the battery box on the same day and the set humidity threshold. The determination method is as follows: on the basis that the duration of the pressure inside the battery box being less than 0 is greater than the second set duration, if the condition that the humidity of the external environment of the battery box on the same day is greater than the set humidity threshold is satisfied at the same time, it is determined that there is a risk of condensation inside the battery box.

[0031] Taking the condensation risk monitoring of the battery box 1 as an example, as Figure 1 shown, first, it is judged whether the pressure P1 inside the battery box 1 is negative (i.e., P1 < 0); if P1 satisfies the condition that P1 is negative, then it is determined whether there is a risk of condensation inside the battery box 1 according to the judgment results of the following two judgments.

[0032] 1) Determine whether the duration T of the pressure inside the battery box being less than 0 is greater than N hours (i.e., the second set duration) through big data; 2) Determine whether the humidity M of the external environment of the battery box on the same day is greater than the set humidity threshold M0 (i.e., M > M0).

[0033] If the judgment results of the above two judgments are both affirmative, it means that at this time, the battery box is not only in an external environment with a relatively low temperature, but also the humidity of this external environment is relatively high; in this embodiment, the above two judgments are set because when only one of the conditions is satisfied, condensation may not actually form inside the battery box (i.e., the basic conditions for forming condensation may not be available), resulting in misjudgment. For example, when the vehicle is driving in an arid desert area, although the external temperature at night is relatively low, the humidity is extremely low (i.e., the water vapor content is insufficient), and condensation will not occur inside the battery box. This embodiment believes that only when the judgment results of 1) and 2) are both affirmative can the basic conditions for generating condensation be provided, and thus the vehicle is determined to be a vehicle with a high risk of condensation.

[0034] Embodiment of the condensation risk monitoring system for the battery box This embodiment provides a technical solution for a condensation risk monitoring system for a battery box. In this embodiment, the condensation risk monitoring method for the battery box in the embodiment of the condensation risk monitoring method for the battery box is adopted, and the condensation risk monitoring method for the battery box can be realized.

[0035] Since the specific working mode and working principle of the condensation risk monitoring system for the battery box in this embodiment have been described in detail in the above embodiment of the condensation risk monitoring method for the battery box, they will not be elaborated here.

[0036] It should be understood that the above specific embodiments of the present invention are only for illustrative or explanatory purposes of the principles of the present invention and do not constitute a limitation on the present invention.

Claims

1. A pressure monitoring method for a battery box, characterized in that, Including: Subtracting the air pressure value of the internal environment of the battery box from the air pressure value of the external environment of the battery box obtained at the same moment for the same battery box, and using the obtained difference as the internal pressure of the battery box; If the condition that the internal pressure of the battery box is greater than the set air pressure threshold is satisfied, it is determined that the internal pressure of the battery box is abnormal; The set air pressure threshold is greater than 0.

2. The pressure monitoring method of the battery box according to claim 1, characterized in that, Also including: On the basis that the internal pressure of the battery box is greater than the set air pressure threshold, if the condition that the internal pressure of the battery box is greater than the set air pressure threshold and less than the thermal runaway alarm threshold is satisfied, it is determined that the situation of the abnormal internal pressure of the battery box is: the battery box is in the early warning stage; in this case, judge the magnitude relationship between the internal pressure of the battery box, the set air pressure threshold and the thermal runaway alarm threshold; If the condition that the internal pressure of the battery box is greater than the thermal runaway alarm threshold is satisfied, it is determined that the situation of the abnormal internal pressure of the battery box is: the battery in the battery box is in thermal runaway; the thermal runaway alarm threshold is greater than the set air pressure threshold.

3. The pressure monitoring method of the battery box according to claim 1 or 2, characterized in that, The methods for obtaining the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box include: measuring the air pressure value of the internal environment of the battery box through the built-in air pressure sensor of the battery box; measuring the air pressure value of the internal and external environments of the battery box through the external air pressure sensor of the battery box; the external air pressure sensor and the built-in air pressure sensor have the same model.

4. A pressure monitoring system for a battery box, characterized in that, Including a processor, characterized in that the processor is used to execute a computer program to implement the steps of the method for monitoring the pressure of the battery box according to any one of claims 1-3.

5. A method for monitoring the condensation risk of a battery box, characterized in that, Including: Subtracting the air pressure value of the internal environment of the battery box from the air pressure value of the external environment of the battery box obtained at the same moment for the same battery box, and using the obtained difference as the internal pressure of the battery box; On the basis that the duration of the situation where the internal pressure of the battery box is less than 0 is greater than the second set duration, if the condition that the humidity of the external environment of the battery box on the same day is greater than the set humidity threshold is simultaneously satisfied, it is determined that there is a risk of condensation in the battery box.

6. The method for monitoring the condensation risk of the battery box according to claim 5, wherein, The methods for obtaining the air pressure value of the internal environment of the battery box and the air pressure value of the external environment of the battery box include: measuring the air pressure value of the internal environment of the battery box through the built-in air pressure sensor of the battery box; measuring the air pressure value of the internal and external environments of the battery box through the external air pressure sensor of the battery box; the external air pressure sensor and the built-in air pressure sensor have the same model.

7. A condensation risk monitoring system for a battery box, characterized in that, Including a processor, characterized in that the processor is used to execute a computer program to implement the steps of the method for monitoring the condensation risk of the battery box according to claim 5 or 6.

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