Battery unit pressure detection device, safety early warning device and management system

Abstract

The utility model provides a battery unit pressure detection device, a battery safety early warning device and a battery management system. The battery unit pressure detection device is used for detecting the internal pressure change of a battery unit and comprises a capacitance detection electrode, the capacitance detection electrode and the explosion-proof valve are arranged at an interval, so that a coupling capacitor is formed between the capacitance detection electrode and the explosion-proof valve, and the capacitance detection electrode is used for detecting the internal pressure change of the battery unit. When the internal pressure of the battery unit changes, the distance between the anti-explosion valve and the capacitance detection electrode changes, the capacitance value of the coupling capacitor changes, and the change of the capacitance value is in negative correlation with the change of the internal pressure of the battery unit.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the safe detection technical field of new energy battery, especially relate to battery unit pressure detection device, battery safety early warning device and battery management system. BACKGROUND

[0002] Thermal runaway is the most serious safety accident of new energy battery, can cause the electric energy and chemical energy stored in the new energy battery inside to release in a short time in a large amount, make the temperature inside new energy battery can even reach above 900 DEG C, simultaneously thermal runaway electrolyte, active material decomposition produces a large amount of gas can cause the pressure inside the battery to rise sharply, even cause the explosion of new energy battery. SUMMARY

[0003] In order to solve one of the above technical problems, the present disclosure provides a battery unit pressure detection device, a battery safety early warning device and a battery management system.

[0004] According to one aspect of the present disclosure, a battery unit pressure detection device is provided for detecting internal pressure changes of a battery unit, the battery unit pressure detection device comprising: a capacitance detection electrode, the capacitance detection electrode being disposed in spaced relation to the explosion-proof valve, whereby a coupling capacitance is formed between the capacitance detection electrode and the explosion-proof valve, when the internal pressure of the battery unit changes, the spacing between the explosion-proof valve and the capacitance detection electrode changes, the capacitance value of the coupling capacitance changes, wherein the change in the capacitance value is negatively correlated with the change in the internal pressure of the battery unit.

[0005] According to the battery unit pressure detection device of at least one embodiment of the present disclosure, the capacitance detection electrode is attached to the battery unit in electrical insulation, or to the edge of the explosion-proof valve in electrical insulation.

[0006] According to the battery unit pressure detection device of at least one embodiment of the present disclosure, further comprising a detection circuit for detecting the capacitance value of the coupling capacitance.

[0007] According to the battery unit pressure detection device of at least one embodiment of the present disclosure, the detection circuit comprises an analog-to-digital converter for detecting the capacitance value of the coupling capacitance.

[0008] According to the battery unit pressure detection device of at least one embodiment of the present disclosure, the change in the capacitance value of the coupling capacitance is converted into a change in current, voltage or signal frequency, and the change in the capacitance value of the coupling capacitance is obtained by detecting the change in current, voltage or signal frequency.

[0009] According to the battery cell pressure detection device of at least one embodiment of the present disclosure, the explosion-proof valve is concave with respect to the battery cell, and the capacitance detection electrode is flush with the battery cell.

[0010] According to the battery cell pressure detection device of at least one embodiment of the present disclosure, the explosion-proof valve is concave with respect to the battery cell, and the capacitance detection electrode is flush with the battery cell.

[0011] According to the battery cell pressure detection device of at least one embodiment of the present disclosure, the explosion-proof valve is concave with respect to the battery cell, and the capacitance detection electrode is flush with the battery cell.

[0012] According to another aspect of the present disclosure, there is provided a battery safety warning device including the battery cell pressure detection device as described above, and a warning signal generation unit generating a warning signal according to a change in the capacitance value of the coupling capacitance.

[0013] According to still another aspect of the present disclosure, there is provided a battery management system including the battery cell pressure detection device as described above, or including the battery safety warning device as described above. BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure.

[0015] Figure 1 A schematic view of a battery according to one embodiment of the present disclosure is shown.

[0016] Figure 2 A fixing method of a capacitance detection electrode and a battery cell according to one embodiment of the present disclosure is shown.

[0017] Figure 3 A fixing method of a capacitance detection electrode and a battery cell according to another embodiment of the present disclosure is shown.

[0018] Figure 4 A disposition method of a capacitance detection chip according to one embodiment of the present disclosure is shown.

[0019] Figure 5 An example of detecting a coupling capacitance using an analog-to-digital converter circuit according to one embodiment of the present disclosure is shown.

[0020] Figure 6 A schematic view of a battery safety warning device according to one embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0021] The present disclosure will be described in further detail below with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the present disclosure and are not intended to limit the present disclosure. In addition, it should be noted that, for the purpose of clarity, only parts of the present disclosure that are related to the present disclosure are shown in the drawings.

[0022] It should be noted that the embodiments and features of the embodiments in the present disclosure can be combined with each other without conflict. The technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] Unless otherwise specified, the exemplary embodiments / instances shown will be understood as providing exemplary features of various details that can implement the technical concepts of the present disclosure in practice. Therefore, unless otherwise specified, the features of various embodiments / instances can be additionally combined, separated, interchanged and / or rearranged without departing from the technical concepts of the present disclosure.

[0024] In the drawings, cross-hatching and / or shading are generally used to indicate that a portion of one component is positioned above another component. As such, unless otherwise specified, the presence of cross-hatching or shading is not a requirement of the present disclosure. In addition, for clarity and / or descriptive purposes, the sizes of the components shown in the drawings can be exaggerated relative to other components. When the exemplary embodiments can be carried out in different ways, a specific process sequence can be performed in a different order from the described order. For example, two consecutively described processes can be performed substantially simultaneously or in the reverse order from the described order. In addition, the same reference numerals represent the same components.

[0025] When a component is referred to as being "on" or "above" another component, "connected to" or "coupled to" another component, it can be directly on, directly connected to, or directly coupled to the other component, or there can be intervening components. However, when a component is referred to as being "directly on", "directly connected to", or "directly coupled to" another component, there are no intervening components. For this reason, the term "connected" can refer to a physical connection, an electrical connection, etc., with or without intervening components.

[0026] For descriptive purposes, the disclosure can use spatially relative terms, such as "below," "beneath," "lower," "under," "above," "upper," "over," and the like, to describe the relative position of one component to another in the drawings as placed in the figures. The spatially relative terms are intended to encompass different positions of the devices in use, operation, and / or manufacture in the different orientations of the devices in the figures. For example, if a device in the figures is turned over, then a component described as "below" or "beneath" another component or feature would then be oriented "above" the other component or feature. Thus, the exemplary term "below" can encompass both an orientation of above and below. Moreover, the devices can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0027] A battery cell of a new energy battery such as a lithium battery is provided with a burst valve. If the internal pressure of the battery pack reaches a limit value, the burst valve will automatically open to release the internal pressure and ensure the safety of the battery. In the related art, all battery pressure detection technologies are to monitor the pressure of the battery pack (for example, a pressure detection device is arranged outside the battery pack). The root cause of the change of the internal pressure of the battery pack is that the battery cell in the battery pack bursts the burst valve due to excessive internal pressure, thereby causing gas leakage, at this time, the battery cell is in a thermal runaway state. That is, in the related art, the pressure change of the battery pack is only monitored after the gas leakage occurs, and therefore the thermal runaway monitoring of the battery does not have sufficient advance.

[0028] Unlike the prior art, in the present disclosure, the pressure change in the interior of a single battery cell is monitored by detecting the deformation of the shell of the single battery cell (the burst valve is also part of the shell or mounted to the shell), and through high-precision capacitive detection means, the pressure change in the interior of the battery cell can be predicted in advance before the burst valve breaks, thereby providing a greater advance for the thermal runaway warning of the battery. Specifically, in the present application, the internal pressure of the battery cell is monitored by monitoring the deformation of the burst valve, and the safety warning of the battery is given in advance before the gas leakage occurs in the interior of the battery cell.

[0029] Before the specific embodiments of the present application are described, the following terms are first explained in order to better understand the content of the present application.

[0030] Explosion-proof valve: also known as safety valve or pressure relief valve, is an important safety device designed to prevent the battery from exploding or rupturing due to excessive internal pressure under abnormal conditions. When excessive gas is generated inside the battery cell, these gases will increase the internal pressure of the battery cell. If the pressure exceeds the safety range, the explosion-proof valve will automatically open to release excess pressure, thereby protecting the battery and the user's safety. Its application scenarios can include power batteries of electric vehicles, batteries of portable electronic devices, battery modules of energy storage systems, etc.

[0031] According to one embodiment of the present disclosure, a battery cell pressure detection device is provided. Figure 1 A schematic diagram of a battery cell according to one embodiment of the present disclosure is shown.

[0032] As shown in Figure 1 , an explosion-proof valve 300 is installed on the battery cell 100. By detecting the deformation of the explosion-proof valve, the internal pressure of the battery cell can be detected, so that faults and the like can be detected before gas leakage occurs inside the battery cell. In order to detect the deformation of the explosion-proof valve, a capacitive detection electrode 400 (shown in dashed lines) can be provided. The explosion-proof valve 300 and the capacitive detection electrode 400 constitute a battery cell pressure detection device.

[0033] As shown in Figure 1 , the capacitive detection electrode 400 is arranged spaced apart from the explosion-proof valve 300. A coupling capacitor is formed between the capacitive detection electrode 400 and the explosion-proof valve 300. The explosion-proof valve 300 is arranged in a concave form with respect to the battery cell 100. The explosion-proof valve 300 can generally be a thin sheet of metal with notches. The capacitive detection electrode 400 can be in the form of an electrode sheet and is provided with an overlapping portion with the explosion-proof valve 300, and a coupling capacitor can be formed between the overlapping portions. Here, overlapping means that the projections between the two have overlapping portions.

[0034] In this application, the capacitive detection electrode 400 can be in the form of a sheet, and the explosion-proof valve 300 can be in the form of a concave. The capacitive detection electrode 400 in the form of a sheet can be arranged outside the explosion-proof valve 300. The explosion-proof valve 300 and the capacitive detection electrode 400 are electrically insulated. In addition, since the shell of the battery cell 100 is usually made of metal material, the capacitive detection electrode 400 and the battery cell 100 are also electrically insulated.

[0035] As shown in Figure 2 , the capacitive detection electrode 400 (shown in dashed lines) can be fixed to the battery cell 100. For example, it is fixed to the battery cell 100 at a fixed position 410. An insulating layer can be provided between the battery cell 100 and the capacitive detection electrode 400, thereby ensuring electrical insulation between the capacitive detection electrode 400 and the battery cell 100 and the explosion-proof valve 300.

[0036] As shown in Figure 3 , the capacitance detection electrode 400 (shown in dashed line) can be fixed to the explosion-proof valve 300. For example, the capacitance detection electrode 400 (shown in dashed line) can be fixed to the edge 310 of the explosion-proof valve 300. An insulating layer can be arranged between the edge 310 of the explosion-proof valve 300 and the capacitance detection electrode 400, and the capacitance detection electrode 400 is electrically insulated from both the battery cell 100 and the explosion-proof valve 300.

[0037] As mentioned above, a coupling capacitance can be formed between the capacitance detection electrode 400 and the explosion-proof valve 300. When the internal pressure of the battery cell 100 changes, for example, due to temperature rise, the explosion-proof valve 300 will deform, but will not be broken, because at this time there is no internal gas leakage in the battery cell. The change of the internal pressure will press the explosion-proof valve 300 towards the capacitance detection electrode 400, so that the distance between the explosion-proof valve 300 and the capacitance detection electrode 400 will change, and the capacitance value of the coupling capacitance between the explosion-proof valve 300 and the capacitance detection electrode 400 will change due to the change of the distance. For example, the capacitance value will increase due to the decrease of the distance. Therefore, in this application, the change of the capacitance value of the coupling capacitance is negatively related to the change of the internal pressure of the battery cell.

[0038] By detecting the capacitance value of the coupling capacitance, the distance between the explosion-proof valve 300 and the capacitance detection electrode 400 can be obtained, and then the deformation of the explosion-proof valve 300 can be obtained, and finally the internal pressure of the battery cell 100 can be obtained.

[0039] As an example, the mutual relationship between the capacitance value of the coupling capacitance and the distance between the explosion-proof valve 300 and the capacitance detection electrode 400, i.e. the corresponding relationship between the capacitance value of the coupling capacitance and the distance, can be established in advance. After the capacitance value is detected, the distance can be determined by using the obtained capacitance value through table lookup method or the like. In addition, the corresponding relationship between the internal pressure of the battery cell and the distance can also be established in advance, so that after the distance is obtained, the internal pressure of the battery cell can be obtained according to the distance. For these technical contents, they can be known by prior experimental measurement, and will not be described in detail herein.

[0040] In order to measure the coupling capacitance between the explosion-proof valve 300 and the capacitance detection electrode 400, a capacitance detection chip or a capacitance detection module can be used. As shown in Figure 4 , the capacitance detection chip 500 is used for detection.

[0041] As an example, an analog-to-digital converter circuit can be used to detect the coupling capacitance. In Figure 5 , the way of measuring the coupling capacitance by using the analog-to-digital converter circuit is shown. As shown in Figure 5The two inputs of the analog-to-digital converter circuit receive signals from the capacitance detection electrode 400 and the explosion-proof valve 300 respectively, and the analog-to-digital converter circuit obtains a digital signal according to the two signals. Alternatively, the capacitance value can be converted into a voltage signal, a current signal or a frequency signal, and the capacitance value can be obtained by measuring the voltage signal, the current signal or the frequency signal. For the specific conversion mode, refer to the related content of the prior art.

[0042] According to another embodiment of the present application, a battery safety warning device is provided, as shown in Figure 6 The battery safety warning device can include the battery cell pressure detection device as described above. The battery safety warning device can further include a warning signal generation unit 600. The warning signal generation unit 600 can receive a signal from the capacitance detection chip 500. The warning signal generation unit 600 judges the safety of the battery according to the received signal.

[0043] As an example, the warning signal generation unit can generate an alarm signal according to the rate of change of the measured capacitance value of the coupling capacitance. For example, the change amount of the capacitance value within a predetermined time interval can be obtained to obtain the rate of change. If the rate of change exceeds the rate of change threshold value within a certain predetermined time interval, an alarm signal can be generated to alarm the safety of the battery.

[0044] As another example, the warning signal generation unit can generate an alarm signal according to the measured capacitance value of the coupling capacitance. For example, when the measured capacitance value is less than the capacitance threshold value, an alarm signal can be generated to alarm the safety of the battery.

[0045] As a further example, the warning signal generation unit can generate an alarm signal according to the difference between the measured capacitance values of different time periods. For example, when the capacitance difference measured in two time periods is greater than the capacitance difference threshold value, an alarm signal can be generated to alarm the safety of the battery.

[0046] According to a further embodiment of the present disclosure, a battery management system is also provided, which can include the battery safety warning device or the battery cell pressure detection device.

[0047] In the description of the specification, the description of the terms "one embodiment / way", "some embodiments / ways", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment / way or example. Also, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments / ways or examples. In addition, the person skilled in the art can combine and combine the different embodiments / ways or examples described in the specification and the features of the different embodiments / ways or examples, without contradiction.

[0048] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0049] The person skilled in the art should understand that the above-mentioned embodiments are only for clearly illustrating the present disclosure, and are not intended to limit the scope of the present disclosure. Based on the above disclosure, other changes or modifications can also be made by those skilled in the art, and these changes or modifications are still within the scope of the present disclosure.

Claims

1. A battery cell pressure detection apparatus characterized by comprising: The battery cell pressure detection device is used for detecting the internal pressure change of a battery cell, the battery cell is installed with a burst valve, and the battery cell pressure detection device comprises: a capacitance detection electrode, which is arranged in a spaced manner with the burst valve, so that a coupling capacitance is formed between the capacitance detection electrode and the burst valve, when the internal pressure of the battery cell changes, the distance between the burst valve and the capacitance detection electrode changes, the capacitance value of the coupling capacitance changes, and the change of the capacitance value is negatively correlated with the change of the internal pressure of the battery cell.

2. The battery cell pressure detection apparatus according to claim 1, wherein The capacitance detection electrode is attached to the battery cell in an electrically insulated manner, or is attached to the edge of the burst valve in an electrically insulated manner.

3. The battery cell pressure detection apparatus according to claim 1, wherein Further comprising a detection circuit, which is used for detecting the capacitance value of the coupling capacitance.

4. The battery cell pressure detection apparatus according to claim 3, wherein The detection circuit comprises an analog-to-digital converter, which detects the capacitance value of the coupling capacitance.

5. The battery cell pressure detection apparatus of claim 4, wherein The change of the capacitance value of the coupling capacitance is converted into the change of current, voltage or signal frequency, and the change of the capacitance value of the coupling capacitance is obtained by detecting the change of the current, voltage or signal frequency.

6. The battery cell pressure detection apparatus according to any one of claims 1 to 5, wherein The burst valve is in a concave form relative to the battery cell, and the capacitance detection electrode is in a flush form relative to the battery cell.

7. The battery cell pressure detection apparatus of claim 6, wherein The burst valve is integrally formed with the capacitance detection electrode and is installed to the battery cell.

8. The battery cell pressure detection apparatus according to any one of claims 1 to 5, wherein The capacitance detection electrode is in a sheet shape, and the sheet-shaped capacitance detection electrode has a projection overlap part with the burst valve.

9. A battery safety warning device, characterized by, Comprise: The battery cell pressure detection device according to any one of claims 1 to 8; A pre-warning signal generation unit, which generates a pre-warning signal according to the change of the capacitance value of the coupling capacitance.

10. A battery management system, characterized by, Comprise the battery cell pressure detection device according to any one of claims 1 to 8, or comprise the battery safety pre-warning device according to claim 9.

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