Battery detection device, battery module and battery system detection method

Abstract

The invention provides a battery detection device, a battery module and a battery system detection method. The battery detection device comprises a rigid part, a piezoelectric detection assembly and a control part, the rigid part is suitable for being arranged on the battery cell module in a sleeving mode and attached to the outer wall face of the battery cell module, the piezoelectric detection assembly is attached to the side, away from the battery cell module, of the rigid part, and the control part is electrically connected with the piezoelectric detection assembly. And the control part is configured to determine the state of the battery cell module based on the output voltage data of the piezoelectric detection assembly. According to the battery detection device, the detection of the battery cell module can be realized without a large number of detection sensors, and the detection complexity and the detection cost of the battery cell module are reduced. And a detection element does not need to be arranged in the battery cell module, so that the damage to the mechanical boundary condition of the module is avoided, and the test error caused by the damage to the mechanical boundary condition of the battery cell module can be effectively avoided.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery detection device, a battery module and a battery system detection method. Background Art

[0002] During the production and use of batteries, the battery cell modules need to be tested accordingly.

[0003] In the related art, detection is mainly achieved by disposing a large number of detection sensors in the battery cell module to obtain corresponding data, which is prone to measurement errors. Summary of the invention

[0004] The embodiments of the present application provide a battery detection device, a battery module and a battery system detection method, which can improve the technical problem that measurement errors are prone to occur in battery cell module detection.

[0005] In a first aspect, an embodiment of the present application provides a battery detection device, comprising:

[0006] A rigid member, suitable for being sleeved on the battery cell module and being fitted with the outer wall surface of the battery cell module;

[0007] A piezoelectric detection component is attached to a side of the rigid component away from the battery module;

[0008] A control component is electrically connected to the piezoelectric detection component, and the control component is configured to determine the state of the battery cell module based on output voltage data of the piezoelectric detection component.

[0009] In one embodiment, the piezoelectric detection component includes a piezoelectric detection component, the inner wall surface of the rigid component is suitable for fitting with the battery core module, the piezoelectric detection component is attached to the outer wall surface of the rigid component, and the piezoelectric detection component is used to detect the stress of the rigid component.

[0010] In one embodiment, the piezoelectric detection element includes a vibration excitation part and a signal pickup part, the vibration excitation part is used to generate vibration to drive the signal pickup part to generate vibration, and the signal pickup part is used to detect the vibration and convert it into a voltage signal output.

[0011] In one embodiment, the piezoelectric detection assembly includes at least two piezoelectric detection members, and the at least two piezoelectric detection members are respectively connected to different positions of the rigid member.

[0012] In one embodiment, the piezoelectric detection component includes at least two piezoelectric detection components both attached to the rigid component, and the at least two piezoelectric detection components include a first piezoelectric detection component and a second piezoelectric detection component, the first piezoelectric detection component is formed with a vibration excitation part, and the vibration excitation part is used to generate vibration, and the second piezoelectric detection component is formed with a signal pickup part, and the signal pickup part is used to detect vibration and convert it into a voltage signal output.

[0013] In one embodiment, the thickness of the rigid member is between 0.1 mm and 0.5 mm.

[0014] In a second aspect, an embodiment of the present application provides a battery module, including a battery cell module and the above-mentioned battery detection device, wherein the rigid member is sleeved on the battery cell module.

[0015] In one embodiment, the battery detection device includes at least two rigid members, and at least two rigid members are sleeved on the battery cell module, and the outer wall surface of each rigid member is connected to the piezoelectric detection component.

[0016] In a third aspect, an embodiment of the present application provides a battery system detection method, including:

[0017] Obtaining the current output voltage of the piezoelectric detection component;

[0018] Based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage, the state of the battery cell module and the pre-tightening force applied to the battery cell module are determined.

[0019] In one embodiment, the step of determining the state of the battery module based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage includes:

[0020] The health status of the battery cell module is determined based on the current voltage difference of the piezoelectric detection component and a health status database, wherein the health status database includes the health status of the battery cell module corresponding to different voltage differences of the piezoelectric detection component.

[0021] In one embodiment, the step of determining the state of the battery module based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage includes:

[0022] Based on the current voltage difference value and the reference value of the piezoelectric detection component, determining that the battery cell module is in a thermal runaway state;

[0023] The reference value is the voltage difference of the piezoelectric detection component when thermal runaway occurs in the battery cell module.

[0024] In one embodiment, the piezoelectric detection components are provided at different positions of the rigid member, and the step of determining the state of the battery module based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage includes:

[0025] Obtaining voltage differences of the piezoelectric detection component at different positions of the rigid member;

[0026] Based on the voltage difference of the piezoelectric detection component at different positions of the rigid member, the alignment state of the multiple battery cells of the battery cell module is determined.

[0027] In one embodiment, the step of determining the health status of the battery cell module based on the current voltage difference of the piezoelectric detection component and the health status database includes:

[0028] Obtaining the current temperature and current voltage of the battery cell module;

[0029] Determine the health status of the battery cell module based on the current temperature, the current voltage, the current voltage difference and the health status database;

[0030] The health status database includes the current voltage difference of the piezoelectric detection component when the battery module is at different temperatures, different voltages and different health states.

[0031] Beneficial effects of the embodiments of the present application:

[0032] In the embodiment of the present application, the rigid part is set on the outer wall surface of the battery module, and the piezoelectric detection component will output a reference voltage. When the state of the battery module changes, the piezoelectric coefficient of the piezoelectric detection component will change due to the adhesion of the rigid part and the outer wall surface of the battery module, and the piezoelectric detection component is attached to the rigid part, and the voltage output by the piezoelectric detection component will also change, that is, the state of the battery module is related to the voltage output of the piezoelectric detection component. The present application detects the change value of the output voltage of the piezoelectric detection component through the control component, and the state of the battery module can be determined according to the change value of the output voltage of the piezoelectric detection component, and then the detection of the battery module can be realized without a large number of detection sensors, which reduces the detection complexity and detection cost of the battery module. And there is no need to set the detection element inside the battery module to avoid damage to the mechanical boundary conditions of the module itself, which can effectively avoid the test error caused by the destruction of the mechanical boundary conditions of the battery module. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 is a schematic diagram of the structure of a battery detection device provided in an embodiment of the present application;

[0035] Figure 2 is a schematic diagram of the structure of a battery detection device provided in an embodiment of the present application, wherein a rigid member is sleeved on a battery cell module;

[0036] Figure 3 It is one of the top views of the battery detection device provided in the embodiment of the present application;

[0037] Figure 4 This is a second top view of the battery detection device provided in an embodiment of the present application;

[0038] Figure 5 is a schematic diagram of the structure of a battery detection device provided in an embodiment of the present application;

[0039] Figure 6 It is one of the structural schematic diagrams of the piezoelectric detection element provided in the embodiment of the present application;

[0040] Figure 7 This is the second structural schematic diagram of the piezoelectric detection element provided in the embodiment of the present application;

[0041] Figure 8 This is the third structural schematic diagram of the piezoelectric detection element provided in the embodiment of the present application;

[0042] Fig. 9 It is a flow chart of a battery system detection method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0044] Combine the following Figures 1 to 9 The present invention describes a battery detection device, a battery module and a battery system detection method.

[0045] According to the embodiment of the first aspect of the present application, Figure 1 , Figure 2 and Figure 3 The battery detection device includes a rigid part 1, a piezoelectric detection component 2 and a control component. The rigid part 1 is suitable for being sleeved on the battery cell module 3 and being attached to the outer wall surface of the battery cell module 3. The piezoelectric detection component 2 is attached to the side of the rigid part 1 away from the battery cell module 3. The control component is electrically connected to the piezoelectric detection component. The control component is configured to determine the state of the battery cell module based on the output voltage data of the piezoelectric detection component.

[0046] According to the battery detection device of the embodiment of the present application, the rigid part 1 is set on the outer wall surface of the battery module 3, and the piezoelectric detection component 2 will output a reference voltage. When the state of the battery module 3 changes, the piezoelectric detection component 2 is attached to the rigid part 1 because the rigid part 1 and the outer wall surface of the battery module 3 are attached, and the piezoelectric detection component 2 is attached to the rigid part 1, and the piezoelectric coefficient of the piezoelectric detection component 2 will change, and then the voltage output by the piezoelectric detection component 2 will also change, that is, the state of the battery module 3 is related to the voltage output of the piezoelectric detection component 2. The present application detects the change value of the output voltage of the piezoelectric detection component 2 through the control component, and the state of the battery module 3 can be determined according to the change value of the output voltage of the piezoelectric detection component 2, and then the detection of the battery module 3 can be realized without a large number of detection sensors, which reduces the detection complexity and detection cost of the battery module 3. And there is no need to set a detection element inside the battery module 3 to avoid damage to the mechanical boundary conditions of the module itself, which can effectively avoid the test error caused by the destruction of the mechanical boundary conditions of the battery module 3.

[0047] Exemplarily, a mapping relationship between the state of the battery cell module 3 and the change value of the output voltage of the piezoelectric detection component 2 can be established in advance. When the change value of the output voltage of the piezoelectric detection component 2 is obtained, the state of the battery cell module can be determined according to the mapping relationship.

[0048] It is also possible to first use the change in the output voltage of the piezoelectric detection component 2 to determine the change in the piezoelectric coefficient of the piezoelectric detection component 2. The stress of the rigid part 1 can be determined based on the change in the piezoelectric coefficient, and then the state of the battery module 3 can be determined, thereby realizing the detection of the state of the battery module 3. Specifically, since the piezoelectric detection component 2 is attached to the rigid part 1, the piezoelectric detection component 2 will be affected by the stress of the rigid part 1, and the piezoelectric coefficient of the piezoelectric detection component 2 will change, causing the voltage output by the piezoelectric detection component 2 to change. When the state of the battery module 3 changes, the stress of the rigid part 1 will change accordingly. In other words, the stress of the rigid part 1 is first determined by the change in the output voltage of the piezoelectric detection component, and then the state of the battery module 3 can be determined by the stress of the rigid part 1.

[0049] It is understandable that when the rigid part 1 is sleeved on the outer wall of the battery cell module 3, the rigid part 1 needs to apply a certain pre-tightening force to the battery cell module 3 to fix the battery cell module 3 and prevent the battery cell module 3 from being in a loose state. While the rigid part 1 applies the pre-tightening force to the battery cell module 3, the rigid part 1 will also generate corresponding stress, which will cause the piezoelectric coefficient of the piezoelectric detection component 2 to change. Then, the voltage output by the piezoelectric detection component 2 when it is attached to the rigid part 1 will be different from the voltage output by the piezoelectric detection component 2 when the rigid part 1 is sleeved on the battery cell module 3. The change in the output voltage of the piezoelectric detection component 2 can be used to determine the change in the piezoelectric coefficient, and the stress of the rigid part 1 can be determined based on the change in the piezoelectric coefficient. The pre-tightening force of the battery cell module 3 can be determined by the stress of the rigid part 1.

[0050] It is understandable that the control component can obtain the output voltage of the piezoelectric detection component 21 at different time points, that is, the control component can determine the change value of the output voltage of the piezoelectric detection component 21 according to the output voltage data of the piezoelectric detection component 21. The change value of the piezoelectric coefficient of the piezoelectric detection component 21 can be calculated according to the change value of the output voltage, and then the control component can determine the stress of the rigid component 1 according to the change value of the piezoelectric coefficient, thereby realizing the detection of the stress of the rigid component 1.

[0051] Exemplarily, when the piezoelectric detection component 21 is attached to the rigid component 1, the control component can obtain the output voltage of the piezoelectric detection component 21 at this time (described below as the first voltage). After the rigid component 1 is mounted on the battery module 3, the control component can obtain the output voltage of the piezoelectric detection component 21 at this time (described below as the second voltage). After the battery module 3 has been used for a certain period of time, the control component can obtain the output voltage of the piezoelectric detection component 21 at this time (described below as the third voltage). The control component can calculate the change in the piezoelectric coefficient of the piezoelectric detection component 21 after the rigid component 1 is mounted on the battery module 3 based on the first voltage and the second voltage. Based on the change in the piezoelectric coefficient, the stress of the rigid component 1 can be determined, and the preload force of the battery module 3 can also be determined. The control component can calculate the change in the piezoelectric coefficient of the piezoelectric detection component 21 based on the second voltage and the third voltage after the battery module 3 has been used for a certain period of time. The stress of the rigid component 1 can be determined based on the change in the piezoelectric coefficient, and the expansion force of the battery module 3 can be determined, thereby determining the health status of the battery module 3.

[0052] In some examples, the piezoelectric detection element 21 is, for example, piezoelectric ceramics.

[0053] It is understandable that when the length of the rigid part 1 changes, the piezoelectric coefficient of the piezoelectric detection component 2 will change due to the influence of the rigid part 1. The change in the piezoelectric coefficient can be determined by the change in the output voltage of the piezoelectric detection component 2, and the change in the length of the rigid part 1 can be inferred based on the change in the piezoelectric coefficient. Since the strain of the rigid part 1 and the stress of the rigid part 1 are related, the stress of the rigid part 1 can be determined based on the change in the length of the rigid part 1. In other words, the stress of the rigid part 1 can be calculated based on the detection data of the piezoelectric detection component 2, and then the state of the battery module 3 can be detected using the stress of the rigid part 1.

[0054] It is understandable that applying an AC excitation signal along the polarization direction of the piezoelectric detection component 2 causes the entire piezoelectric detection component 2 to be in a vibrating state, and the signal pickup area of ​​the piezoelectric detection component 2 will output a corresponding voltage.

[0055] Exemplarily, the applied AC excitation signal is ensured to remain unchanged so that the vibration state of the piezoelectric detection component 2 remains unchanged, that is, the output voltage of the piezoelectric detection component 2 is only affected by the piezoelectric coefficient of the piezoelectric detection component 2, and then the change data of the piezoelectric coefficient of the piezoelectric detection component 2 can be determined through the output voltage data of the piezoelectric detection component 2.

[0056] In some examples, the rigid member 1 is, for example, a steel strip or an aluminum strip. It should be noted that the rigid member 1 is merely illustrated here and is not specifically limited to the rigid member 1.

[0057] In one embodiment of the present application, Figure 1 , Figure 2 and Figure 4 The piezoelectric detection component 2 includes a piezoelectric detection component 21. The inner wall surface of the rigid component 1 is suitable for fitting with the battery core module 3. The piezoelectric detection component 21 is attached to the outer wall surface of the rigid component 1. The piezoelectric detection component 21 is used to detect the stress of the rigid component 1.

[0058] It is understandable that the stress of the rigid part 1 can be detected by the piezoelectric detection part 21 to determine the stress change of the rigid part 1. The state of the battery cell module 3 can be judged according to the stress change of the rigid part 1, thereby realizing the detection of the battery cell module 3.

[0059] Combine the following Figure 6 , Figure 7 and Figure 8 The piezoelectric detection element 21 is described. Figure 6 , Figure 7 and Figure 8 The arrow in represents the polarization direction of the piezoelectric detection element 21. Figure 6 The vibration excitation part 211 and the signal pickup part 212 are both thickness polarized; Figure 7 In the embodiment, the vibration excitation part 211 is polarized along the length direction of the piezoelectric detection element 21, and the signal pickup part 212 is polarized along the thickness direction of the piezoelectric detection element 21; Figure 8 The vibration excitation portion 211 is interdigitally polarized along the piezoelectric detection element 21 , and the signal pickup portion 212 is polarized along the thickness direction of the piezoelectric detection element 21 .

[0060] like Figure 6 , Figure 7 and Figure 8 The piezoelectric detection element 21 includes a vibration excitation part 211 and a signal pickup part 212. The vibration excitation part 211 is used to generate vibration to drive the signal pickup part 212 to generate vibration. The signal pickup part 212 is used to detect the vibration and convert it into a voltage signal for output.

[0061] It is understandable that the vibration excitation part 211 is stimulated by an electrical signal, so that the entire piezoelectric detection part 21 is in a vibrating state, that is, the vibration is transmitted to the signal pickup part 212, so that the corresponding voltage can be output at the signal pickup part 212. In this embodiment, the vibration excitation part 211 and the signal pickup part 212 are integrated into the same piezoelectric detection part 21, and the stress detection of the rigid part 1 can be realized by using one piezoelectric detection part 21, which simplifies the structure of the battery detection device.

[0062] In some embodiments, the piezoelectric detection assembly 2 includes at least two piezoelectric detection components 21 , and the at least two piezoelectric detection components 21 are respectively connected to different positions of the rigid component 1 .

[0063] It is understandable that by sleeve-mounting the rigid part 1 on the outer wall surface of the battery cell module 3 , the rigid part 1 can fasten the multiple battery cells of the battery cell module 3 . Meanwhile, under the action of the battery cell module 3 , the rigid part 1 will also generate corresponding stress.

[0064] When the multiple cells of the cell module 3 are neatly arranged, that is, the multiple cells are aligned, the force exerted by the cell module 3 on the rigid part 1 will be uniform. Then the stresses at at least two different positions of the rigid part 1 are detected by the piezoelectric detection component 2. When the stresses at different positions of the rigid part 1 are the same or the difference is within the preset value, it means that the multiple cells of the cell module 3 are aligned with each other at this time. When the stresses at different positions of the rigid part 1 are different or the difference is greater than the preset value, it means that the multiple cells of the cell module 3 are not aligned with each other at this time. In other words, the present application sets piezoelectric detection components 21 at different positions of the rigid part 1, and according to the change value of the output voltage of the signal pickup part 212 of the piezoelectric detection component 21 at different positions, the stress at different positions of the rigid part 1 can be determined. By comparing the stress values ​​at different positions, the force uniformity of the cell module 3 can be obtained, and it can be determined whether the multiple cells of the cell module 3 are aligned with each other, thereby realizing the detection of the alignment state of the cell module 3.

[0065] In some embodiments, Figure 2 The piezoelectric detection component 2 includes at least two piezoelectric detection components 21 both attached to the rigid component 1. The at least two piezoelectric detection components 21 include a first piezoelectric detection component and a second piezoelectric detection component. The first piezoelectric detection component is formed with a vibration excitation portion 211, and the vibration excitation portion 211 is used to generate vibration. The second piezoelectric detection component is formed with a signal pickup portion 212, and the signal pickup portion 212 is used to detect vibration and convert it into a voltage signal output.

[0066] It can be understood that the vibration excitation part 211 of the first piezoelectric detection element is stimulated by an electrical signal, so that the first piezoelectric detection element is in a vibrating state. Since the first piezoelectric detection element and the second piezoelectric detection element are both attached to the rigid part 1, the vibration of the first piezoelectric detection element can be transmitted to the second piezoelectric detection element, so that the signal pickup part 212 of the second piezoelectric detection element can detect the vibration and output a corresponding voltage.

[0067] The vibration excitation part 211 and the signal pickup part 212 are respectively arranged at different piezoelectric detection parts 21. The vibration excitation part 211 and the signal pickup part 212 can be arranged separately. The vibration excitation part 211 and the signal pickup part 212 can be arranged at appropriate positions according to actual conditions. For example, the signal pickup part 212 can be arranged in the middle position of the rigid part 1. Under the condition of equal stress, the deformation amount in the middle position of the rigid part 1 is the largest, which can improve the detection accuracy.

[0068] In one embodiment of the present application, Figure 4The rigid part 1 includes a first rigid part 11, a second rigid part 12, a third rigid part 13 and a fourth rigid part 14 which are connected in sequence. The first rigid part 11 and the third rigid part 13 are arranged opposite to each other and have the same length. The second rigid part 12 and the fourth rigid part 14 are arranged opposite to each other and have the same length. The length of the first rigid part 11 is smaller than that of the second rigid part 12. The piezoelectric detection component 2 is connected to the middle position of the second rigid part 12 and / or the fourth rigid part 14.

[0069] It can be understood that the first rigid part 11, the second rigid part 12, the third rigid part 13 and the fourth rigid part 14 are connected end to end to form the rigid part 1, and the first rigid part 11, the second rigid part 12, the third rigid part 13 and the fourth rigid part 14 are all in contact with the outer wall surface of the battery module 3. If the length of the second rigid part 12 and the fourth rigid part 14 is relatively long, the stress on the second rigid part 12 and the fourth rigid part 14 will be greater than the stress on the first rigid part 11 and the third rigid part 13, and at the second rigid part 12 and the fourth rigid part 14, the deformation degree at the middle position of the second rigid part 12 and the fourth rigid part 14 is the largest, and then the piezoelectric detection component 2 is arranged at the middle position of the second rigid part 12 and / or the fourth rigid part 14, which increases the influence of the piezoelectric coefficient of the piezoelectric detection component 2 on the rigid part 1, and ensures the detection accuracy of the piezoelectric detection component 2.

[0070] It can be understood that the piezoelectric detection component 2 can be set at the middle position of the second rigid part 12 and the fourth rigid part 14 at the same time, so that two detection data can be obtained. The two detection data can be used to verify each other. When the two detection data differ too much, it means that one of the piezoelectric detection components 2 may have a problem and needs to be checked in time. The two detection data can also be combined to obtain a more accurate stress of the rigid part 1, thereby improving the detection accuracy.

[0071] In some embodiments, the thickness of the rigid member 1 is between 0.1 mm and 0.5 mm.

[0072] It is understandable that if the thickness of the rigid part 1 is less than 0.1 mm, the structural strength of the rigid part 1 is low and it is easy to be damaged. If the thickness of the rigid part 1 is greater than 0.5 mm, the deformation degree of the rigid part 1 is less affected by the battery module, which reduces the detection accuracy of the piezoelectric detection component 2 and is not conducive to using the piezoelectric detection component to determine the state of the battery module 3. Therefore, the thickness of the rigid part 1 is set between 0.1 mm and 0.5 mm in this application.

[0073] According to an embodiment of the second aspect of the present application, the battery module includes a battery cell module 3 and the battery detection device of the above embodiment, and the rigid member 1 is sleeved on the battery cell module 3.

[0074] According to the battery of the embodiment of the present application, the piezoelectric detection component 2 is used to detect the state and preload of the battery module 3, and there is no need to set up a large number of detection sensors, which reduces the detection complexity and detection cost of the battery module 3. There is no need to set up detection elements inside the battery module 3 to avoid damage to the mechanical boundary conditions of the module itself, which can effectively avoid test errors caused by the destruction of the mechanical boundary conditions of the battery module 3.

[0075] In one embodiment of the present application, Figure 5 The battery detection device includes at least two rigid parts 1, and the at least two rigid parts 1 are sleeved on the battery module 3. The outer wall surface of each rigid part 1 is connected to a piezoelectric detection component 2.

[0076] It can be understood that each rigid part 1 is sleeved on the battery cell module 3, and the outer wall surface of each rigid part 1 is connected to the piezoelectric detection component 2, that is, the stress of each rigid part 1 can be detected, and then the state of the battery cell module 3 can be judged by the stress of each rigid part 1.

[0077] It is understandable that the rigid member 1 is attached to the outer wall surface of the cell module 3, that is, the rigid member 1 can play a role in fastening the cell module 3. By providing at least two rigid members 1 and both being sleeved on the cell module 3, the fastening effect on the cell module 3 is improved.

[0078] By providing a piezoelectric detection component 2 at each rigid part 1, the stress of each rigid part 1 can be detected. When the stress of each rigid part 1 is obtained, the state of different positions of the battery cell module 3 can be judged according to the position of the piezoelectric detection component 2 of different rigid parts 1. The detection data of each piezoelectric detection component 2 can also be combined to obtain more accurate stress data that can represent the overall state of the battery cell module 3, thereby improving the detection accuracy of the battery cell module 3.

[0079] In some examples, when the state of the battery cell module 3 is normal, the stresses of different rigid parts 1 should be the same or the difference should be within the threshold. The stresses of different rigid parts 1 are then compared and calculated to determine whether some stress data are abnormal. If so, the abnormal stress data can be eliminated to ensure the accuracy of the detection.

[0080] In one embodiment of the present application, Figure 5 The piezoelectric detection components 2 at two adjacent rigid parts 1 are symmetrically distributed about the symmetry plane of the two adjacent rigid parts 1.

[0081] It is understandable that after the rigid part 1 is sleeved on the battery module 3, the battery module 3 will be subjected to a certain preload force, and the rigid part 1 will have a certain stress. At this time, if the multiple batteries of the battery module 3 are neatly arranged, because the piezoelectric detection components 2 at two adjacent rigid parts 1 are symmetrical to each other, the stress at the position where the two adjacent rigid parts 1 are connected to the piezoelectric detection components 2 should be the same, that is, the detection data of the piezoelectric detection components 2 at two adjacent rigid parts 1 should be the same, and then by determining whether the detection data of the piezoelectric detection components 2 at two adjacent rigid parts 1 are the same, it can be determined whether the multiple batteries of the battery module 3 are neatly arranged.

[0082] According to an embodiment of the third aspect of the present application, Fig. 9 The battery system detection method of the battery detection device based on the above embodiment includes:

[0083] Step 101 : Obtain the current output voltage of the piezoelectric detection component 2 .

[0084] It can be understood that the current output voltage of the piezoelectric detection component 2 is obtained by monitoring the piezoelectric detection component 2 .

[0085] Step 102 : determining the state of the battery cell module 3 and the preload force applied to the battery cell module 3 based on the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage.

[0086] It is understandable that when the rigid part 1 is sleeved on the battery module 3, the piezoelectric detection component 2 will output a reference voltage, and as the state of the battery module 3 changes, the stress of the rigid part 1 will change accordingly. Since the piezoelectric detection component 2 is attached to the rigid part 1 and is affected by the rigid part 1, the piezoelectric coefficient of the piezoelectric detection component 2 will change, causing the voltage output by the piezoelectric detection component 2 to change. The current voltage and reference voltage output by the piezoelectric detection component 2 can be used to determine the state of the battery module 3 according to the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage. The change in the piezoelectric coefficient of the piezoelectric detection component 2 can be determined according to the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage, the stress of the rigid part 1 can be determined according to the change in the piezoelectric coefficient, and the preload force on the battery module 3 can be determined according to the stress of the rigid part 1.

[0087] For example, the battery cell module 3 can be placed in different states by controlling the number of charge and discharge times or the temperature, and then the current output voltage of the piezoelectric detection component 2 when the battery cell module 3 is in different states can be obtained to determine the mapping relationship between the voltage difference and the state of the battery cell module 3. Subsequently, the state of the battery cell module 3 can be directly determined based on the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage.

[0088] It can be understood that by setting up the first battery cell module and the second battery cell module which are completely identical, setting up the piezoelectric detection component 2 at the rigid part 1 at the first battery cell module, and setting up the stress sensor at the rigid part 1 at the second battery cell module, the first battery cell module 3 and the second battery cell module 3 are completely identical, and then the voltage difference of the output voltage of the piezoelectric detection component 2 can be matched with the stress detected by the stress sensor, and the corresponding relationship can be stored in the control component, so that when the control component determines the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage, the stress of the rigid part 1 can be determined. After the rigid part 1 is sleeved on the battery cell module 3, the battery cell module 3 will be subjected to the preload force applied by the rigid part 1, and the rigid part 1 will also generate corresponding stress, and then according to the stress of the rigid part 1, the preload force of the battery cell module 3 can be calculated.

[0089] Exemplarily, the state of the battery cell module 3 and the preload force applied to the battery cell module 3 can be directly determined based on the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage. Specifically, there is a mapping relationship between the state of the battery cell module 3 and the voltage difference, and there is also a mapping relationship between the preload force applied to the battery cell module 3 and the voltage difference. When the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage is determined, the state of the battery cell module 3 and the preload force applied can be directly determined based on the mapping relationship.

[0090] The stress of the rigid part 1 can also be calculated by first using the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage, completing the conversion between the voltage difference and the stress, and then determining the state of the battery cell module 3 and the preload force it is subjected to based on the stress of the rigid part 1.

[0091] In some examples, the stress of the rigid component 1 and the preload force of the battery cell module 3 may be in a linear relationship or a nonlinear relationship.

[0092] It can be understood that the rigid part 1 fits the battery cell module 3 , and the stress of the rigid part 1 is associated with the state of the battery cell module 3 , that is, the state of the battery cell module 3 can be determined by analyzing the stress of the rigid part 1 .

[0093] According to the battery system detection method of the embodiment of the present application, the stress of the rigid part 1 can be determined by the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage to judge the state and / or preload of the battery cell module 3, and the battery cell module 3 can be detected without a large number of detection sensors, thereby reducing the detection complexity and detection cost of the battery cell module 3. There is no need to place sensors between the battery cells of the battery cell module 3, and the detection process will not destroy the mechanical boundary conditions of the battery cell module 3 itself, thereby ensuring the detection accuracy.

[0094] It is understandable that the rigid part 1 is sleeved on the outer wall surface of the battery cell module 3, and the rigid part 1 applies a certain pre-tightening force to the battery cell module 3 to fix the battery cell module 3 and prevent the battery cell module 3 from being in a loose state. While the rigid part 1 applies the pre-tightening force to the battery cell module 3, the rigid part 1 will also generate corresponding stress, and the piezoelectric detection component 2 can detect the stress of the rigid part 1, and the pre-tightening force of the battery cell module 3 can be determined by the stress of the rigid part 1. In other words, the present application detects the stress of the rigid part 1 through the piezoelectric detection component 2, and the pre-tightening force of the battery cell module 3 can be determined according to the stress, and the piezoelectric detection component 2 can be connected to the side of the rigid part 1 away from the battery cell module 3, and the pre-tightening force of the battery cell module 3 can be detected without placing a sensor between the batteries of the battery cell module 3. The detection process will not destroy the mechanical boundary conditions of the battery cell module 3 itself, and the measurement accuracy of the pre-tightening force of the battery cell module 3 is guaranteed.

[0095] In the related art, a method of placing a thin film or other types of pressure sensors between battery cells is usually adopted to test the preload force of the battery cell module 3. In addition to changing the mechanical boundary conditions of the module itself and causing certain test errors, the above method also requires the use of a large number of sensors, resulting in high detection costs. The piezoelectric detection component 2 of the present application detects the stress of the rigid part 1 and determines the preload force of the battery cell module 3 based on the stress. In addition to avoiding changes in the mechanical boundary conditions of the battery cell module 3 and ensuring measurement accuracy, it can also effectively reduce the number of detection elements used and reduce detection costs.

[0096] In one embodiment of the present application, the step of determining the state of the battery module 3 based on the voltage difference between the reference voltage of the piezoelectric detection component 2 and the current output voltage includes:

[0097] The health status of the battery cell module is determined based on the current voltage difference of the piezoelectric detection component and a health status database, wherein the health status database includes the health status of the battery cell module corresponding to different voltage differences of the piezoelectric detection component.

[0098] It is understandable that by comparing the current voltage difference of the piezoelectric detection component with the health status database, the health status of the battery cell module 3 corresponding to the current voltage difference can be obtained, thereby realizing the detection of the health status of the battery cell module 3.

[0099] Exemplarily, a battery cell module 3 is set as a calibration battery cell module 3, and a long cycle test is performed on the calibration battery cell module 3, that is, the battery cell module 3 is subjected to multiple charge and discharge cycles, and the SOH state (that is, health state) of the calibration battery cell module 3 and the corresponding voltage difference of the piezoelectric detection component after each cycle are recorded, and the health state and the corresponding voltage difference are stored in a health state database, so that the current health state of the battery cell module 3 can be determined based on the current voltage difference later.

[0100] In one embodiment of the present application, based on the current voltage difference of the piezoelectric detection component and the health status database, the step of determining the health status of the battery cell module includes:

[0101] Get the current temperature and current voltage of the battery module 3;

[0102] Determine the health status of the battery cell module 3 based on the current temperature, the current voltage, the current voltage difference and the health status database;

[0103] The health status database includes the current voltage difference of the piezoelectric detection component when the battery module 3 is at different temperatures, different voltages and different health states.

[0104] It is understandable that when the battery module 3 is at different temperatures and different voltages, the expansion force of the battery module 3 in the same state may be different, that is, the temperature and voltage will affect the current voltage difference of the piezoelectric detection component. Therefore, when determining the health status of the battery module 3, the current temperature and current voltage of the battery module 3 are also obtained, and the current temperature, current voltage, and current voltage difference are compared with the health status database to obtain the health status of the battery module 3, so as to realize the detection of the health status of the battery module 3, and at the same time avoid the influence of temperature and voltage on the health status detection.

[0105] In one embodiment of the present application, the step of determining the state of the battery cell module based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage includes:

[0106] Based on the current voltage difference value and the reference value of the piezoelectric detection component, it is determined that the battery cell module 3 is in a thermal runaway state;

[0107] The reference value is the voltage difference of the piezoelectric detection component when thermal runaway occurs in the battery cell module 3 .

[0108] It can be understood that when determining the state of the battery cell module 3, the current voltage difference value of the piezoelectric detection component and the voltage difference value of the piezoelectric detection component when the battery cell module 3 is in a thermal runaway state are compared. When the current voltage difference value and the voltage difference value of the piezoelectric detection component when the battery cell module 3 is in a thermal runaway state are the same, it means that the battery cell module 3 is in a thermal runaway state.

[0109] In an embodiment of the present application, based on the current voltage difference value and the reference value of the piezoelectric detection component, the step of determining that the battery cell module 3 is in a thermal runaway state includes:

[0110] Get the current temperature and current voltage of the battery module 3;

[0111] Determine a reference value based on the current temperature, the current voltage and a thermal runaway database, wherein the thermal runaway database includes a voltage difference of the piezoelectric detection component when thermal runaway occurs in the battery cell module 3 under different temperatures and different voltages;

[0112] Based on the current voltage difference of the piezoelectric detection component and the reference value, it is determined that the battery cell module 3 is in a thermal runaway state.

[0113] It is understandable that when the battery cell module 3 is at different temperatures and different voltages, the expansion force of the battery cell module 3 in the same state may be different, that is, the voltage will affect the voltage difference of the piezoelectric detection component of the rigid part 1. Therefore, when determining whether the battery cell module 3 is in a thermal runaway state, the current temperature and current voltage of the battery cell module 3 will be obtained first, and the current temperature, current voltage and thermal runaway database will be compared. When the battery cell module 3 has thermal runaway under the current temperature and current voltage conditions, the reference value of the voltage difference of the piezoelectric detection component can be obtained, and then the current voltage difference of the piezoelectric detection component and the reference value are compared. When the current voltage difference of the piezoelectric detection component and the reference value are the same, it means that the battery cell module 3 is in a thermal runaway state, and the thermal runaway state of the battery cell module 3 is detected, and the influence of temperature and voltage on the detection can be effectively reduced.

[0114] In one embodiment of the present application, piezoelectric detection components are provided at different positions of the rigid member, and the step of determining the state of the battery cell module based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage includes:

[0115] Obtaining voltage differences of the piezoelectric detection component at different positions of the rigid member;

[0116] Based on the voltage difference of the piezoelectric detection component at different positions of the rigid part, the alignment status of multiple battery cells of the battery cell module is determined.

[0117] It can be understood that when the rigid part 1 fits the battery module 3 and the multiple batteries of the battery module 3 are neatly arranged, that is, when the multiple batteries are aligned, the force of the battery module 3 acting on the rigid part 1 will be uniform, that is, the voltage difference of the piezoelectric detection components at different positions of the rigid part 1 should be the same or the difference is less than the preset value. Then, by analyzing the voltage difference of the piezoelectric detection components at different positions of the rigid part 1, the alignment state of the multiple batteries of the battery module 3 can be determined.

[0118] According to the battery alignment detection method of the embodiment of the present application, by obtaining the voltage difference of the piezoelectric detection components at different positions of the rigid part 1, the voltage difference of the piezoelectric detection components at different positions of the rigid part 1 is compared. When the voltage difference of the piezoelectric detection components at different positions of the rigid part 1 is the same or the difference is less than a preset value, it means that the force on the rigid part 1 is uniform and the multiple battery cells of the battery cell module 3 are aligned. When the difference of the voltage difference of the piezoelectric detection components at different positions of the rigid part 1 is greater than the preset value, it means that the force on the rigid part 1 is uneven and the multiple battery cells of the battery cell module 3 are not aligned, thereby realizing the detection of the alignment status of the multiple battery cells of the battery cell module 3.

[0119] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A battery detection device, characterized in that: include: A rigid member, suitable for being sleeved on the battery cell module and being fitted with the outer wall surface of the battery cell module; A piezoelectric detection component is attached to a side of the rigid component away from the battery module; A control component is electrically connected to the piezoelectric detection component, and the control component is configured to determine the state of the battery cell module based on output voltage data of the piezoelectric detection component.

2. The battery detection device according to claim 1, characterized in that: The piezoelectric detection assembly includes a piezoelectric detection component. The inner wall surface of the rigid component is suitable for fitting with the battery core module. The piezoelectric detection component is attached to the outer wall surface of the rigid component. The piezoelectric detection component is used to detect the stress of the rigid component.

3. The battery detection device according to claim 2, characterized in that: The piezoelectric detection element includes a vibration excitation part and a signal pickup part. The vibration excitation part is used to generate vibration to drive the signal pickup part to generate vibration. The signal pickup part is used to detect the vibration and convert it into a voltage signal for output.

4. The battery detection device according to claim 3, characterized in that: The piezoelectric detection assembly includes at least two piezoelectric detection members, and the at least two piezoelectric detection members are respectively connected to different positions of the rigid member.

5. The battery detection device according to claim 2, characterized in that: The piezoelectric detection component includes at least two piezoelectric detection components both attached to the rigid component, and the at least two piezoelectric detection components include a first piezoelectric detection component and a second piezoelectric detection component. The first piezoelectric detection component is formed with a vibration excitation part, and the vibration excitation part is used to generate vibration. The second piezoelectric detection component is formed with a signal pickup part, and the signal pickup part is used to detect vibration and convert it into a voltage signal output.

6. The battery testing device according to any one of claims 1 to 5, characterized in that: The thickness of the rigid part is between 0.1 mm and 0.5 mm.

7. A battery module, characterized in that: It comprises a battery cell module and a battery detection device as claimed in any one of claims 1 to 6, wherein the rigid member is sleeved on the battery cell module.

8. The battery module according to claim 7, characterized in that: The battery detection device comprises at least two rigid parts, and at least two rigid parts are sleeved on the battery core module. The outer wall surface of each rigid part is connected to the piezoelectric detection component.

9. A battery system detection method based on the battery detection device according to any one of claims 1 to 6, characterized in that: include: Obtaining the current output voltage of the piezoelectric detection component; Based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage, the state of the battery cell module and the pre-tightening force applied to the battery cell module are determined.

10. The battery system detection method according to claim 9, characterized in that: The step of determining the state of the battery module based on the voltage difference between the reference voltage of the piezoelectric detection component and the current output voltage includes: The health status of the battery cell module is determined based on the current voltage difference of the piezoelectric detection component and a health status database, wherein the health status database includes the health status of the battery cell module corresponding to different voltage differences of the piezoelectric detection component.

11. The battery system detection method according to claim 10, characterized in that: The step of determining the health status of the battery cell module based on the current voltage difference of the piezoelectric detection component and the health status database includes: Obtaining the current temperature and current voltage of the battery cell module; Determine the health status of the battery cell module based on the current temperature, the current voltage, the current voltage difference and the health status database; The health status database includes the current voltage difference of the piezoelectric detection component when the battery module is at different temperatures, different voltages and different health states.

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