Battery cell testing methods, packaging structure, battery cells, batteries, and electrical equipment.

Abstract

This application provides a cell testing method, a packaging structure, a cell, a battery, and an electrical device, relating to the field of battery technology. The cell testing method is applied to a cell and includes: setting an electroluminescent film on the cell's packaging film, and electrically connecting the electroluminescent film to a first tab led out from the cell via a conductive element; detecting whether the electroluminescent film emits light to determine the electrical connection state between the second tab led out from the cell and the packaging film, thereby determining whether the cell is short-circuited. This cell testing method can solve the problem of inaccurately identifying whether a cell has a short circuit when it comes off the production line, leading to defective products being released.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a cell testing method, packaging structure, cell, battery, and electrical equipment. Background Technology

[0002] The tabs are metallic conductors that lead the positive and negative terminals out of the battery cell, serving as contact points during charging and discharging. When the tabs come into contact with the outer casing, electrical continuity occurs between the tabs and the cell's outer shell, causing a short circuit. This results in a large current flowing inside the cell, leading to overheating and potentially even an explosion risk.

[0003] Therefore, it is necessary to detect whether the battery cell has a short circuit. For example, this can be done by testing the resistance of the contacts. In related technologies, a wire is typically used to connect one of the tabs to the aluminum-plastic film, and a voltage is applied by an external power source to test the cell's resistance. However, when the contact area of ​​the tab is small, its impact on the cell's resistance is minimal, making it easy to miss and posing a risk of leakage. Summary of the Invention

[0004] This application provides a cell testing method, packaging structure, cell, battery, and electrical device, which can solve the problem of not being able to accurately identify whether a cell has a short circuit when it comes off the production line, resulting in defective products being released.

[0005] In a first aspect, this application provides a battery cell testing method, applied to battery cells, the method comprising:

[0006] An electroluminescent film is disposed on the encapsulation film of the battery cell, and the electroluminescent film is electrically connected to the first electrode led out from the battery cell through a conductive component;

[0007] Detecting whether the electroluminescent film emits light is used to determine the electrical connection status between the second tab led out from the battery cell and the encapsulation film, thereby determining whether the battery cell is short-circuited.

[0008] The battery cell testing method provided in this application includes an electroluminescent film on the battery cell's encapsulation film. The electroluminescent film is electrically connected to the encapsulation film. The encapsulation film is electrically connected to the first tab via a conductive element. Therefore, when the second tab contacts the casing, i.e., when the second tab is electrically connected to the encapsulation film, a connected circuit can be formed between the electroluminescent film, the encapsulation film, the first tab, the second tab, and the battery cell. It is easy to understand that at this time, the battery cell is in a short-circuit state. The battery cell can provide voltage to the electroluminescent film. Therefore, workers or users can determine whether a short circuit exists in the battery cell based on whether the electroluminescent film emits light.

[0009] Therefore, as long as the second tab contacts the casing, the resulting closed loop can be used to provide an electric field for the electroluminescent film to emit light, regardless of the size of the contact area between the second tab and the encapsulation film. In other words, even when the contact area between the second tab and the encapsulation film is small, accurate identification of a short circuit in the battery cell is still possible. Workers or users can accurately determine whether the second tab has contacted the casing based on whether the electroluminescent film emits light, thus confirming whether the battery cell is short-circuited and reducing the possibility of short-circuited cells leaking out.

[0010] According to one embodiment of this application, detecting whether the electroluminescent film emits light to determine the electrical connection state between the second electrode led out from the battery cell and the encapsulation film, thereby determining that the battery cell is short-circuited, includes:

[0011] If the electroluminescent film emits light, it is determined that the second tab and the encapsulation film are electrically connected, and the battery cell is determined to be short-circuited.

[0012] If the electroluminescent film is detected to be non-luminescent, it is determined that the second tab and the encapsulation film are in a non-electrically connected state.

[0013] According to one embodiment of this application, after detecting whether the electroluminescent film emits light to determine the electrical connection state between the second electrode led out from the battery cell and the encapsulation film, the method further includes:

[0014] If it is determined that the battery cell is short-circuited, then the luminescence intensity of the electroluminescent film is detected;

[0015] The contact area between the second tab and the encapsulation film is determined based on the luminescence intensity of the electroluminescent film, wherein the luminescence intensity is proportional to the contact area.

[0016] According to one embodiment of this application, the number of electroluminescent films is multiple, and the multiple electroluminescent films have the same voltage threshold and different current thresholds;

[0017] Determining the contact area between the second electrode and the encapsulation film based on the luminescence intensity of the electroluminescent film includes:

[0018] The contact area between the second tab and the encapsulation film is determined based on the electroluminescent film with the highest luminescence intensity among the plurality of electroluminescent films.

[0019] Secondly, this application provides a packaging structure for packaging a positive electrode, a separator, and a negative electrode, wherein one of the positive and negative electrode sheets has a first tab, and the other of the positive and negative electrode sheets has a second tab. The packaging structure includes:

[0020] An encapsulation film, wherein the encapsulation film is electrically connected to the first electrode tab via a conductive element;

[0021] An electroluminescent film is disposed on the encapsulation film, and the electroluminescent film is used to determine the electrical connection state between the second electrode and the encapsulation film based on its own luminescence state.

[0022] According to one embodiment of this application, the encapsulation film includes a barrier layer, the barrier layer being electrically connected to the first tab via the conductive element, and the electroluminescent film being disposed on the outer surface of the barrier layer.

[0023] According to one embodiment of this application, the encapsulation film further includes an adhesive layer, and the electroluminescent film is fixed to the barrier layer through the adhesive layer.

[0024] According to one embodiment of this application, the electroluminescent film comprises silicates, oxides, rare earth organics, inorganic powders, and conductive oil films.

[0025] According to one embodiment of this application, the number of electroluminescent films is multiple; the voltage thresholds of the multiple electroluminescent films are the same, and the current thresholds of the multiple electroluminescent films are different.

[0026] According to one embodiment of this application, a plurality of the electroluminescent films are spaced apart along the long side of the encapsulation structure.

[0027] Thirdly, this application provides a battery cell, which includes:

[0028] First pole ear;

[0029] The second electrode has the opposite polarity to the first electrode.

[0030] In any of the above embodiments, a portion of the first tab and a portion of the second tab are exposed outside the packaging structure.

[0031] A conductive element, one end of which is electrically connected to the first electrode tab, and the other end of which is electrically connected to the encapsulation film.

[0032] Fourthly, this application provides a battery, including the cell found in any of the above embodiments.

[0033] Fifthly, the present application provides an electrical device comprising at least one battery cell or battery.

[0034] In addition to the technical problems solved by the embodiments of the present invention described above, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions, other technical problems that can be solved by the cell testing method, packaging structure, cell, battery, and electrical equipment provided by the embodiments of the present invention, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific embodiments. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] Figure 1 This is a flowchart of a cell testing method according to an embodiment of this application;

[0037] Figure 2 This is a flowchart of a cell testing method according to another embodiment of this application;

[0038] Figure 3 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application;

[0039] Figure 4 This is a schematic diagram of the structure of a battery cell according to another embodiment of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 100-cell;

[0042] 110 - Encapsulation structure; 111 - Encapsulation film; 112 - Electroluminescent film;

[0043] 120 - First pole ear;

[0044] 130 - Second pole ear;

[0045] 140 - Conductive component;

[0046] 10-External power supply.

[0047] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0048] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. Clearly, the described embodiments are only a portion, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0049] The battery cell provided in this application embodiment can be a lithium-ion battery cell. For example, a lithium-ion secondary battery cell, a lithium-sulfur battery cell, or a sodium-lithium-ion battery cell, etc. This application does not limit the specific type of battery cell.

[0050] The battery cells provided in this application embodiment can be used in electrical devices. These electrical devices can be conventional electrical devices in the art, such as power equipment (e.g., electric vehicles), electronic devices (e.g., mobile phones, tablets, laptops, digital cameras), and wearable devices (e.g., watches, bracelets, VR glasses), and are not limited thereto.

[0051] For small electronic devices and wearable devices, a single battery cell may suffice. However, for vehicles such as electric vehicles, multiple cells can be used to form a battery module. This battery module can serve as a driving power source for the vehicle, replacing or partially replacing fuel, thus providing propulsion. For example, the battery module can provide electrical energy to the drive motor. The drive motor is connected to the wheels of the vehicle via a transmission mechanism, thereby propelling the vehicle.

[0052] The battery cell includes two electrodes with opposite polarities and a separator. The electrodes with opposite polarities are the positive and negative electrodes. The separator is located between the positive and negative electrodes to insulate them. The positive electrode, separator, and negative electrode can be formed into a wound battery cell using a winding process. Alternatively, the positive electrode, separator, and negative electrode can be stacked in a specific order to form a laminated battery cell, which is not limited in the embodiments of this application.

[0053] A battery cell includes two tabs with opposite polarities: a positive tab and a negative tab. The positive tab can be led out from a positive electrode plate, and the negative tab can be led out from a negative electrode plate. The positive and negative tabs can be used to connect to external circuits.

[0054] During charging, lithium atoms in the positive electrode lose electrons and transform into lithium ions. These lithium ions migrate through the electrolyte to the negative electrode under the influence of an electric field. In the negative electrode, the lithium ions are captured by the micropores of the graphite layered structure and combine with electrons flowing in from the external circuit to form lithium intercalation compounds. In this process, the electrical energy provided by the external power source can be converted into chemical energy and stored in the battery cell.

[0055] In some examples, the battery cell in this application embodiment can be a pouch cell. The pouch cell is externally encapsulated with an aluminum-plastic film or similar film. Part of the positive tab and part of the negative tab can be led out to the outside of the cell. The positive and negative tabs are insulated from the encapsulation film by tab adhesive.

[0056] The tabs, as metallic conductors leading the positive and negative electrodes out of the battery cell, are the contact points during charging and discharging. When the tab (positive or negative) becomes electrically connected to the encapsulation film, i.e., when the tab contacts the casing, it causes electrical continuity between the positive and negative electrodes, resulting in a short circuit in the battery cell. This generates a large current inside the cell, causing it to heat up and even posing a risk of explosion.

[0057] Therefore, it is necessary to check for short circuits in battery cells just before they are produced. This can be done, for example, by testing the resistance of the contacts. In related technologies, a wire is typically used to connect one of the tabs to an aluminum-plastic film, and an external power supply is applied to test the cell's resistance. However, when the contact area of ​​the tab is small, its impact on the cell's resistance is minimal, making it easy to miss and posing a risk of leakage.

[0058] Based on the aforementioned technical problems, the applicant has improved the existing battery cell testing method. In this embodiment, an electroluminescent film may be provided on the battery cell's encapsulation film. The electroluminescent film is electrically connected to the encapsulation film. The encapsulation film is electrically connected to the first tab via a conductive element. Therefore, when the second tab contacts the casing, i.e., when the second tab is electrically connected to the encapsulation film, a connected circuit can be formed between the electroluminescent film, the encapsulation film, the first tab, the second tab, and the battery cell. It is easy to understand that at this time, the battery cell is in a short-circuit state. The battery cell can provide voltage to the electroluminescent film. Therefore, workers or users can determine whether there is a short circuit in the battery cell based on whether the electroluminescent film emits light.

[0059] The following description, with reference to the accompanying drawings and specific embodiments, describes the cell testing method, packaging structure, cell, battery, and electrical equipment provided in this application.

[0060] See Figures 1 to 4As shown, the cell testing method is applied to a battery cell. The battery cell 100 may include an encapsulation structure 110, a first tab 120, and a second tab 130. The encapsulation structure 110 may include an encapsulation film 111 and an electroluminescent film 112. The encapsulation film 111 encapsulates the battery cell 100. The electroluminescent film 112 is disposed on and electrically connected to the encapsulation film 111. The electroluminescent film 112 is electrically connected to the first tab 120 via a conductive element 140. The conductive element 140 may be a wire or other metallic conductive material.

[0061] See Figure 1 As shown, the cell testing method of this application embodiment includes:

[0062] S100. An electroluminescent film 112 is disposed on the encapsulation film 111 of the battery cell 100, and the electroluminescent film 112 is electrically connected to the first tab 120 led out from the battery cell 100 through a conductive element 140.

[0063] S200: Detect whether the electroluminescent film 112 emits light to determine the electrical connection status between the second tab 130 led out from the battery cell 100 and the encapsulation film 111, thereby determining whether the battery cell 100 is short-circuited.

[0064] The electroluminescent film 112 is a material that can emit light under the influence of an electric field. When a power source is configured to provide an electric field for the electroluminescent film 112, the electroluminescent film 112 can produce light emission. That is, under the stimulation of the electric field, when electrons and holes inside the electroluminescent film 112 material recombine, they release energy and can be emitted in the form of light.

[0065] In this embodiment of the application, the power source used to provide an electric field for the electroluminescent film 112 can be a battery cell 100 or an external power source 10. See also Figure 3 As shown, one end of the external power supply 10 can be electrically connected to the first tab 120 through the conductive element 140, and the other end of the external power supply 10 can be electrically connected to the second tab 130 through another conductive element 140, so as to provide an electric field for the electroluminescent film 112.

[0066] This application describes the use of the battery cell 100 as an example to provide an electric field for the electroluminescent film 112.

[0067] In some examples, the electroluminescent film 112 may include semiconductor materials such as silicates, oxides, rare earth organics, and inorganic powders, as well as a conductive oil film.

[0068] In some examples, the electroluminescent film 112 may include electroluminescent powder and a conductive oil film.

[0069] In some examples, the color of the light emitted by the electroluminescent film 112 can be set according to the material of the electroluminescent film 112. In this embodiment, the color of the emitted light from the electroluminescent film 112 is not limited. For example, the color of the electroluminescent film 112 can be red, blue, green, etc.

[0070] It should be noted that one of the first tab 120 and the second tab 130 is a positive tab, and the other is a negative tab; this is not limited in the embodiments of this application. When the first tab 120 is used as a positive tab and electrically connected to the electroluminescent film 112 through the conductive element 140, whether the electroluminescent film 112 emits light can be used to detect the contact phenomenon of the negative tab (second tab 130), that is, the electrical connection state between the negative tab (second tab 130) and the encapsulation film 111. Similarly, when the first tab 120 is used as a negative tab and electrically connected to the electroluminescent film 112 through the conductive element 140, whether the electroluminescent film 112 emits light can be used to detect the contact phenomenon of the positive tab (second tab 130), that is, the electrical connection state between the positive tab (second tab 130) and the encapsulation film 111.

[0071] In some examples, the emission of light from the electroluminescent film 112 can be used to determine that the second tab 130 is electrically connected to the encapsulation film 111.

[0072] Specifically, since the electroluminescent film 112 is electrically connected to the first tab 120 and the encapsulation film 111, when the second tab 130 is also electrically connected to the encapsulation film 111, a closed circuit is formed between the electroluminescent film 112, the first tab 120, the encapsulation film 111, the second tab 130, and the battery cell 100. At this time, the battery cell 100 can provide an electric field to the electroluminescent film 112, causing the electroluminescent film 112 to emit light. It is easy to understand that because a closed circuit is formed between the electroluminescent film 112, the first tab 120, the encapsulation film 111, the second tab 130, and the battery cell 100, the first tab 120 and the second tab 130, with opposite polarities, are electrically connected, causing a short circuit in the battery cell 100.

[0073] Correspondingly, when there is no electrical connection between the second tab 130 and the encapsulation film 111, there is no connection between the first tab 120 and the second tab 130, the battery cell 100 cannot provide an electric field to the encapsulation film 111, and the electroluminescent film 112 will not emit light. At this time, there is no electrical conduction between the first tab 120 and the second tab 130, and the battery cell 100 is not short-circuited.

[0074] It is easy to understand that since the electrical connection between the second tab 130 and the encapsulation film 111 allows the battery cell 100 to provide the necessary electric field for the electroluminescent film 112 to emit light, the closed circuit formed when the second tab 130 contacts the casing can be used to provide the electric field for the electroluminescent film 112 to emit light, regardless of the size of the contact area between the second tab 130 and the encapsulation film 111. In other words, even when the contact area between the second tab 130 and the encapsulation film 111 is small, accurate identification of a short circuit in the battery cell 100 is still possible. Workers or users can accurately determine whether the second tab 130 has contacted the casing based on whether the electroluminescent film 112 is emitting light, thereby determining whether the battery cell 100 is short-circuited, which helps reduce the possibility of the short-circuited battery cell 100 leaking out.

[0075] In some examples, S200 may specifically include:

[0076] If the electroluminescent film 112 emits light, it is determined that the second tab 130 and the encapsulation film 111 are in an electrically connected state, and the battery cell 100 is determined to be short-circuited.

[0077] If the electroluminescent film 112 is not detected to emit light, it is determined that the second tab 130 and the encapsulation film 111 are in a non-electrically connected state.

[0078] When a short circuit occurs in the battery cell 100, the battery cell 100 can provide the electric field required for the electroluminescent film 112 to emit light, and the electroluminescent film 112 emits light. When the battery cell 100 is not short-circuited, the battery cell 100 cannot provide the electric field required for the electroluminescent film 112 to emit light, and the electroluminescent film 112 does not emit light. Therefore, the method by which users or staff determine whether the battery cell 100 is short-circuited based on whether the electroluminescent film 112 emits light is intuitive, convenient, and accurate.

[0079] In some examples, the battery cell 100 can continuously monitor whether the electroluminescent film 112 emits light during application. When the electroluminescent film 112 emits light, an alert can be issued to prompt the user to take timely action and avoid potential safety hazards.

[0080] In particular, when applied to vehicles, the battery module includes multiple cells 100. When the battery module malfunctions, the luminescence of the electroluminescent film 112 on each cell 100 can be determined to check whether a short circuit has occurred among the multiple cells 100. This allows for quick and accurate identification of the faulty cell 100, enabling maintenance and replacement of the cell 100, which improves maintenance efficiency and reduces safety hazards.

[0081] In some examples, during the process of detecting whether the electroluminescent film 112 emits light on the production line, the staff can observe the luminescence of the electroluminescent film 112 with the naked eye, or the luminescence of the electroluminescent film 112 can be detected by a light sensor. No specific limitation is made in this application.

[0082] For example, the light sensor can be a photosensitive probe. Each battery cell 100 can correspond to one photosensitive probe. The photosensitive probe can monitor the luminescence status of the electroluminescent film 112. When the electroluminescent film 112 emits light, the photosensitive probe can identify the light and send a signal to the battery management system. The user can use the signal indication to troubleshoot the battery cell 100 that has a short circuit.

[0083] Therefore, by setting a light sensor at the battery cell 100 to monitor the electroluminescent film 112, online tracking and detection of the short-circuit condition of the battery cell 100 can be achieved, enabling in-situ monitoring of the short-circuit condition. The battery cell 100 can be directly detected in the application scenario to obtain its current state in real time, thus accurately reflecting the true situation of the battery cell 100's current state. Furthermore, the detection process does not require disassembly of the battery cell 100, making the process simple and convenient.

[0084] In some examples, the applicant tested 1,000 offline cells using the above method and found that 6 batteries had the phenomenon of second tabs 130 contacting the casing. This effectively avoided the risk of defective products being released, which helped to reduce safety hazards and improve user experience.

[0085] See Figure 2 As shown, after S200, it may also include:

[0086] S400 If it is determined that the battery cell 100 is short-circuited, the luminous intensity of the electroluminescent film 112 is detected.

[0087] S500. Based on the luminous intensity of the electroluminescent film 112, determine the contact area between the second tab 130 and the encapsulation film 111. The luminous intensity can be directly proportional to the contact area.

[0088] According to Ohm's law, V = I * R, where V represents voltage, I represents current, and R represents resistance. With a constant voltage, the greater the current, the smaller the resistance. Therefore, when the luminous intensity of the electroluminescent film 112 is strong, the greater the current I passing through it, the smaller the resistance R. The luminous intensity of the electroluminescent film 112 is inversely proportional to its resistance R.

[0089] According to the basic formula for resistance R: R = ρ * (L / S), where R represents resistance, ρ represents the resistivity of the material (an inherent material property, a constant), L represents the length through which the current flows through the material, and S represents the cross-sectional area through which the current flows through the material. Under constant conditions, when the contact area between the second tab 130 and the encapsulation film 111 is large, the cross-sectional area S through which the current flows through the electroluminescent film 112 is larger, and the resistance R is smaller. Therefore, resistance R is inversely proportional to the contact area between the second tab 130 and the encapsulation film 111.

[0090] Since the luminous intensity of the electroluminescent film 112 is inversely proportional to the resistance R, and the resistance R is inversely proportional to the contact area between the second tab 130 and the encapsulation film 111, under constant other conditions, the luminous intensity of the electroluminescent film 112 is directly proportional to the contact area between the second tab 130 and the encapsulation film 111.

[0091] It is easy to understand that when the luminous intensity of the electroluminescent film 112 is high, the current flowing through the electroluminescent film 112 is high, and the resistance value is low. Therefore, there is a relatively large contact area between the second tab 130 and the encapsulation film 111. Workers need to promptly maintain the currently short-circuited cell 100.

[0092] In this embodiment, when the battery cell 100 is short-circuited, the electroluminescent film 112 emits light. At this time, the luminescence state of the electroluminescent film 112 can be used to determine whether there is a large contact area between the second tab 130 and the encapsulation film 111. This helps to collect the probability of the second tab 130 contacting the casing during the manufacturing and use of the battery cell 100, providing guidance for subsequent improvements.

[0093] In some examples, the luminous intensity of the electroluminescent film 112 can be detected by a light sensor. Since the luminous intensity is proportional to the contact area, a luminous intensity threshold can be set. When the light sensor detects that the luminous intensity exceeds the threshold, it can be determined that there is a large contact area between the second tab 130 and the encapsulation film 111, and a maintenance response needs to be issued immediately for the short-circuited cell 100.

[0094] In some examples, the electroluminescent film 112 may have a threshold voltage. When the cell 100 is short-circuited, and the voltage through the electroluminescent film 112 reaches the threshold voltage of the electroluminescent film 112, the electroluminescent film 112 emits light.

[0095] For example, when the number of electroluminescent films 112 is one, electroluminescent films 112 with different threshold voltages can be used.

[0096] Example 1

[0097] Electroluminescent powder emitting red light is mixed with conductive ink to form an electroluminescent film 112, which is then coated onto the surface of the barrier layer (conductive layer) of the encapsulation film 111. The voltage is adjusted so that the threshold voltage of the electroluminescent film 112 is exactly reached at 132V. The electroluminescent film 112 begins to emit light, and the light intensity is measured to be 0.5 lux using a light sensor (e.g., a lux meter). When the voltage is adjusted to 200V, the light intensity is 27 lux.

[0098] Example 2

[0099] An electroluminescent film 112 is formed by mixing red-emitting electroluminescent powder with conductive ink and coated onto the surface of the barrier layer (conductive layer) of the encapsulation film 111. The voltage is adjusted so that the threshold voltage of the electroluminescent film 112 is exactly reached at 184V. The electroluminescent film 112 begins to emit light, and the light intensity is measured to be 0.5 lux using a light sensor (e.g., a lux meter). When the voltage is adjusted to 200V, the light intensity is 4 lux.

[0100] Example 3

[0101] An electroluminescent film 112 is formed by mixing red-emitting electroluminescent powder with conductive ink and coated onto the surface of the barrier layer (conductive layer) of the encapsulation film 111. The voltage is adjusted so that the threshold voltage of the electroluminescent film 112 is exactly reached at 163V. The electroluminescent film 112 begins to emit light, and the light intensity is measured to be 0.5 lux using a light sensor (e.g., a lux meter). When the voltage is adjusted to 200V, the light intensity is 13 lux.

[0102] Comparative Example 1

[0103] When the surface of the untreated cell 100 with the barrier layer (conductive layer) of the encapsulation film 111 is adjusted to 200V, it does not emit light.

[0104]

[0105] Table 1 shows the light intensity at 200V for Examples 1, 2, 3, and Comparative Example 1. The specific testing process involved measuring the light intensity emitted by the electroluminescent film 112 using a light sensor (e.g., a lux meter). It can be seen that the greater the voltage across the electroluminescent film 112 exceeds its threshold voltage, the greater the light intensity emitted by the electroluminescent film 112. Therefore, operators can select electroluminescent films 112 with different threshold voltages based on the specifications of the battery cells 100.

[0106] In some feasible ways, there can be multiple electroluminescent films 112. In other words, multiple electroluminescent films 112 can be provided on the battery cell 100. Among them, the multiple electroluminescent films 112 can have the same voltage threshold and different current thresholds.

[0107] Therefore, when it is determined that the battery cell 100 is short-circuited and all electroluminescent films 112 are in the luminescent state, S600 can determine the size of the contact area between the second tab 130 and the encapsulation film 111 based on the one with the largest luminous intensity among the multiple electroluminescent films 112.

[0108] Since multiple electroluminescent films 112 correspond to the same voltage threshold, all of them can be in an luminous state when the cell 100 is short-circuited. Because the luminous intensity of the electroluminescent film 112 is proportional to its contact area, the greater the current flowing through the electroluminescent film 112, the stronger the light emitted by it. By setting different current thresholds for the multiple electroluminescent films 112, different luminous intensities can be achieved, allowing the contact area between the second tab 130 and the encapsulation film 111 to be determined based on the luminous intensity.

[0109] Specifically, when multiple electroluminescent films 112 emit light, the corresponding resistance can be obtained based on the current threshold corresponding to the electroluminescent film 112 with the highest luminous intensity. Thus, based on the current threshold and the resistance, the contact area between the second tab 130 and the encapsulation film 111 can be divided into different intervals to maintain different response schemes.

[0110] In some examples, during the process of detecting short-circuit conditions in the battery cell 100, photosensitive sensors can be placed at different nodes on the production line. The photosensitive sensors at different nodes can be used to detect the luminescence state of the electroluminescent film 112 at different locations on the battery cell 100, thereby improving detection efficiency.

[0111] It is easy to understand that when detecting the luminescence state of multiple electroluminescent films 112 using different light sensors, a barrier plate can be set to prevent the brightness of other electroluminescent films 112 from affecting the brightness intensity of the currently detected electroluminescent film 112.

[0112] In some examples, the threshold voltage of the electroluminescent film 112 is related to the conductivity of the light-emitting layer. The clamping electric field strength decreases as the conductivity of the light-emitting layer increases. Furthermore, the material properties of the light-emitting layer of the electroluminescent film 112 can also effectively modulate the threshold voltage of the electroluminescent film 112. Therefore, the threshold voltage of the electroluminescent film 112 can be adjusted by regulating one or more of the conductivity of the light-emitting layer, the preparation method, and the growth conditions.

[0113] For example, in this embodiment, the threshold voltage of the electroluminescent film 112 can be greater than or equal to 2V. When the voltage of the battery cell 100 is greater than the threshold voltage, there is current in the barrier layer within the encapsulation film 111, which is used to make the electroluminescent film 112 emit light.

[0114] See Figure 4 As shown in the embodiment of this application, a packaging structure 110 is also provided, which can be used to package a positive electrode, a separator, and a negative electrode. A first tab 120 can be led out from one of the positive and negative electrode sheets, and a second tab 130 can be led out from the other of the positive and negative electrode sheets.

[0115] The encapsulation structure 110 includes an encapsulation film 111 and an electroluminescent film 112. The encapsulation film 111 is electrically connected to the first tab 120 via a conductive element 140. The electroluminescent film 112 is disposed on the encapsulation film 111. The electroluminescent film 112 is used to determine the electrical connection state between the second tab 130 and the encapsulation film 111 based on its own luminescence state.

[0116] In this embodiment, the encapsulation film 111 can be used to encapsulate the positive electrode, the separator, and the negative electrode. The electroluminescent film 112 is electrically connected to the encapsulation film 111, and the encapsulation film 111 is electrically connected to the first tab 120 via a conductive element 140. Therefore, the first tab 120, the encapsulation film 111, and the electroluminescent film 112 can be electrically connected. When the second tab 130 is electrically connected to the encapsulation film 111, the first tab 120, the encapsulation film 111, the electroluminescent film 112, and the second tab 130 are electrically connected, causing a short circuit in the battery. Furthermore, because the first tab 120, the encapsulation film 111, the electroluminescent film 112, and the second tab 130 are electrically connected, an electric field required for the electroluminescent film 112 to emit light can be provided, enabling the electroluminescent film 112 to emit light.

[0117] In summary, the luminescence state of the electroluminescent film 112 can be used to effectively identify whether the second tab 130 is electrically connected to the encapsulation film 111, thereby identifying whether the battery cell 100 is short-circuited. This detection method has high identification efficiency and high accuracy.

[0118] In some possible implementations, the encapsulation film 111 may include a barrier layer. The barrier layer is electrically connected to the first tab 120 via a conductive element 140. The electroluminescent film 112 may be disposed on the outer surface of the barrier layer.

[0119] In this embodiment, the barrier layer can block the permeation of water vapor and oxygen. Furthermore, the barrier layer can be stamped to provide good support.

[0120] In some examples, the encapsulation film 111 may be, but is not limited to, an aluminum-plastic film. The barrier layer of the encapsulation film 111 may be an aluminum foil layer. The barrier layer is conductive. Therefore, the electroluminescent film 112 may be disposed on the barrier layer to conduct current through the barrier layer.

[0121] It should be noted that the electroluminescent film 112 being disposed on the outer surface of the barrier layer means that the electroluminescent film 112 is located on the exposed surface of the battery cell 100, so as to facilitate staff and users to confirm the luminescence status of the electroluminescent film 112.

[0122] In some feasible embodiments, the encapsulation film 111 of this application embodiment may further include an adhesive layer. The electroluminescent film 112 is fixed to the barrier layer by the adhesive layer.

[0123] The encapsulation film 111 includes an outer resist layer.

[0124] The outer resist layer can reduce the likelihood of oxidation of the barrier layer and also reduce the possibility of damage to the outer surface of the cell 100 due to scratches. The outer resist layer can be, but is not limited to, insulating materials such as nylon. The adhesive layer can be used to bond the barrier layer and the outer resist layer.

[0125] During the fabrication of the encapsulation structure 110, an electroluminescent film 112 can be first coated onto a barrier layer, and then the barrier layer and the outer barrier layer can be bonded together using an adhesive layer, thereby allowing the electroluminescent film 112 to be located between the barrier layer and the outer barrier layer. Alternatively, the powder of the electroluminescent film 112 can be mixed into the adhesive layer. When the barrier layer and the outer barrier layer are bonded together using an adhesive layer, the electroluminescent film 112 can be fixed between the barrier layer and the outer barrier layer.

[0126] See also some of the possible implementation methods. Figure 4 As shown, there can be multiple electroluminescent films 112. The multiple electroluminescent films 112 have the same voltage threshold and different current thresholds.

[0127] When the voltage thresholds of the multiple electroluminescent films 112 are the same, all of them can emit light when a short circuit occurs in the battery cell 100. When the current thresholds of the multiple electroluminescent films 112 are different, the light intensity exhibited by the electroluminescent films 112 can vary when different currents pass through them. The greater the current passing through the electroluminescent films 112, the greater the light intensity of the electroluminescent films 112.

[0128] The larger the electrical connection contact area between the second tab 130 and the encapsulation film 111, the larger the current flowing through the encapsulation film 111 and the electroluminescent film 112, resulting in a smaller resistance and stronger light from the electroluminescent film 112. Therefore, the brightness of multiple electroluminescent films 112 can be used to determine whether the electrical connection contact area between the second tab 130 and the encapsulation film 111 in the currently short-circuited cell 100 is large, allowing for timely maintenance responses.

[0129] In some examples, embodiments of this application do not limit the size or shape of the electroluminescent film 112. For example, Figure 4As shown, the electroluminescent film 112 can be rectangular. There can be gaps between multiple electroluminescent films 112.

[0130] In some feasible ways, multiple electroluminescent films 112 can be spaced apart along the long side of the encapsulation structure.

[0131] In this embodiment, by arranging multiple electroluminescent films 112 at intervals, during the monitoring of the battery cell 100, the light emission state of two adjacent electroluminescent films 112 can be conveniently blocked by an opaque partition to avoid mutual interference between the light emission states of two adjacent electroluminescent films 112, thereby affecting the accuracy of the light sensor detection.

[0132] This application embodiment also provides a battery cell 100. The battery cell 100 may include a first tab 120, a second tab 130, and a packaging structure 110. The first tab 120 and the second tab 130 have opposite polarities.

[0133] Part of the first tab 120 and part of the second tab 130 may be exposed outside the packaging structure 110. One end of the conductive element 140 may be electrically connected to the first tab 120, and the other end of the conductive element 140 may be electrically connected to the encapsulating film 111.

[0134] The battery cell 100 in this embodiment can detect whether it has experienced a short circuit. Therefore, during application, the battery cell 100 can be monitored in real time by a light sensor, so that when a short circuit occurs, the user can be promptly alerted, which helps to improve the safety performance of the battery cell 100 and reduce safety hazards.

[0135] This application also provides a battery. The battery may include the cell 100 from any of the above embodiments.

[0136] This application also provides an electrical device. The electrical device may include at least one battery cell 100 or battery as described in any of the above embodiments. The electrical device may be a new energy vehicle, such as an electric vehicle or a hybrid electric vehicle, or it may be an energy storage device.

[0137] It should be noted that the numerical values ​​and ranges involved in this application are approximate values. Due to the influence of the manufacturing process, there may be a certain range of errors, which can be considered negligible by those skilled in the art.

[0138] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0139] In the description of this application, it should be understood that the terms “center,” “length,” “width,” “thickness,” “top,” “bottom,” “upper,” “lower,” “left,” “right,” “front,” “rear,” “vertical,” “horizontal,” “inner,” “outer,” “axial,” and “circumferential,” etc., used to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the indicated position or component must have a specific orientation, or a specific structure and operation, and therefore should not be construed as a limitation of the present invention.

[0140] The devices or elements referred to in the embodiments of this application or implied herein must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of this application. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0141] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those illustrated or described herein.

[0142] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0143] The term "multiple" in this article refers to two or more. The term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects; in formulas, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0144] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application.

[0145] It is understood that, in the embodiments of this application, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

Claims

1. A method for testing battery cells, applied to battery cells, characterized in that, The method includes: An electroluminescent film is disposed on the encapsulation film of the battery cell, and the electroluminescent film is electrically connected to a first electrode led out from the battery cell through a conductive element; the conductive element is a wire; the encapsulation film includes a barrier layer and an adhesive layer, and the electroluminescent film is fixed to the outer surface of the barrier layer through the adhesive layer; Detecting whether the electroluminescent film emits light is used to determine the electrical connection status between the second electrode led out from the battery cell and the encapsulation film, thereby determining whether the battery cell is short-circuited; If the electroluminescent film emits light, it is determined that the second tab and the encapsulation film are electrically connected, and the battery cell is determined to be short-circuited. And the luminescence intensity of the electroluminescent film is detected; The contact area between the second tab and the encapsulation film is determined based on the luminescence intensity of the electroluminescent film, wherein the luminescence intensity is proportional to the contact area. If the electroluminescent film is detected to be non-luminescent, it is determined that the second tab and the encapsulation film are in a non-electrically connected state.

2. The method according to claim 1, characterized in that, The number of electroluminescent films is multiple, and the multiple electroluminescent films have the same voltage threshold and different current thresholds; Determining the contact area between the second electrode and the encapsulation film based on the luminescence intensity of the electroluminescent film includes: The contact area between the second tab and the encapsulation film is determined based on the electroluminescent film with the highest luminescence intensity among the plurality of electroluminescent films.

3. A packaging structure (110) for packaging a positive electrode, a separator, and a negative electrode, wherein one of the positive electrode and the negative electrode has a first tab (120) leading out, and the other of the positive electrode and the negative electrode has a second tab (130) leading out, characterized in that, include: An encapsulation film (111) is electrically connected to the first tab (120) via a conductive element (140); An electroluminescent film (112) is disposed on the encapsulation film (111). The electroluminescent film (112) is used to determine the electrical connection state between the second tab (130) and the encapsulation film (111) based on its own light emission state.

4. The packaging structure (110) according to claim 3, characterized in that, The encapsulation film (111) includes a barrier layer, which is electrically connected to the first tab (120) through the conductive element (140), and the electroluminescent film (112) is disposed on the outer surface of the barrier layer.

5. The packaging structure (110) according to claim 4, characterized in that, The encapsulation film (111) further includes an adhesive layer, and the electroluminescent film (112) is fixed to the barrier layer through the adhesive layer.

6. The packaging structure (110) according to claim 4, characterized in that, The electroluminescent film (112) comprises silicates, oxides, rare earth organics, inorganic powders, and conductive oil films.

7. The packaging structure (110) according to claim 3, characterized in that, The number of electroluminescent films (112) is multiple; the voltage threshold of the multiple electroluminescent films (112) is the same, and the current threshold of the multiple electroluminescent films (112) is different.

8. The packaging structure (110) according to claim 7, characterized in that, Multiple electroluminescent films (112) are spaced apart along the long side of the encapsulation structure (110).

9. A battery cell, characterized in that, include: First pole ear (120); The second electrode (130) has the opposite polarity to the first electrode (120); In the packaging structure (110) as described in any one of claims 4-8, a portion of the first tab (120) and a portion of the second tab (130) are exposed outside the packaging structure (110); A conductive element (140) is provided, one end of which is electrically connected to the first tab (120), and the other end of which is electrically connected to the encapsulation film (111) of the encapsulation structure.

10. A battery, characterized in that, include: The battery cell according to claim 9.

11. An electrical appliance, characterized in that, include: At least one cell as described in claim 9 or a battery as described in claim 10.

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