Battery polarization distribution characteristic detection method and device

Abstract

The embodiment of the invention provides a battery polarization distribution characteristic detection method and device, and the method comprises the following steps: S10, dividing a first pole piece of a battery into N sub-pole pieces; wherein N is greater than or equal to 2; s20, connecting the N sub-pole pieces in parallel, then converging and connecting the N sub-pole pieces to a first electrode of charging and discharging equipment, and connecting a second pole piece of the battery to a second electrode of the charging and discharging equipment; and S30, obtaining the polarization current of the region corresponding to each sub-pole piece of the N sub-pole pieces, so as to analyze the polarization distribution characteristics of the battery. According to the invention, the complete first pole piece is divided into a plurality of sub pole pieces which are electrically isolated from one another, and the polarization current of the corresponding area of each sub pole piece is independently measured, so that the homogenization effect of a communicated current collector in the battery on the current distribution of the electrode can be reduced, and the local polarization difference of different areas on the surface of the pole piece can be reflected more truly; and data support is provided for analyzing battery polarization distribution characteristics and the like.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and in particular, to a method and device for detecting the polarization distribution characteristics of a battery. Background Art

[0002] In some related technologies, during the operation of a battery, there is non-uniformity in battery polarization, which affects the overall output performance and service life of the battery. Summary of the Invention

[0003] Some embodiments of this application propose a method and device for detecting the polarization distribution characteristics of a battery to optimize battery performance.

[0004] Some embodiments of this application provide a method for detecting the polarization distribution characteristics of a battery, including the following steps: S10: Divide the first pole piece of the battery into N sub-pole pieces; where N is greater than or equal to 2; S20: Connect the N sub-pole pieces in parallel, and then connect them in a current collecting manner to the first electrode of the charge and discharge device, and connect the second pole piece of the battery to the second electrode of the charge and discharge device; and S30: Obtain the polarization current of each corresponding area of the N sub-pole pieces for analyzing the polarization distribution characteristics of the battery.

[0005] In the above embodiment, the complete first pole piece is separated into multiple electrically isolated sub-pole pieces, and the polarization current of each corresponding area of each sub-pole piece is measured independently. Compared with the method of uniformly measuring the whole pole piece, it can reduce the homogenization effect of the connected current collector inside the battery on the electrode current distribution, can more truly reflect the local polarization differences in different areas of the pole piece surface, and the quantitative detection of the local polarization current in different areas of the pole piece surface can obtain the difference information in aspects such as the electrochemical reaction rate, electrolyte distribution, and material activity of each area on the pole piece surface, providing data support for analyzing the polarization distribution characteristics of the battery, etc.

[0006] In some embodiments, the step S10 further includes: sequentially and at intervals make N first pole tabs along the length direction of the first pole piece, and each divided sub-pole piece has a first pole tab.

[0007] In the above embodiment, by configuring an independent first pole tab for each sub-pole piece, the current of each corresponding area of each sub-pole piece can be led out separately, reducing the current equalizing effect of the connected current collector on the current distribution, so as to achieve accurate detection of local electrochemical reactions; in the parallel connection mode, each sub-pole piece is connected to the circuit through an independent first pole tab, which helps to reduce the influence brought by local resistance differences and the influence on the overall current distribution uniformity, and by obtaining the current distribution information in different areas inside the battery, it helps to analyze phenomena such as the polarization distribution characteristics of the battery.

[0008] In some embodiments, step S10 further includes: arranging the N sub-pole pieces flat on the second pole piece in sequence along the length direction of the second pole piece.

[0009] In the above embodiments, by arranging the N sub-pole pieces flat and stacked on the second pole piece in sequence along the length direction of the second pole piece, and arranging a separator between the N sub-pole pieces and the second pole piece to achieve electrical insulation and isolation, a stacked electrode assembly structure is formed. This structure can increase the layout area of the active material within the limited space of the battery housing, thereby improving the energy density per unit volume and per unit mass.

[0010] In some embodiments, step S10 further includes: providing a gap between adjacent two sub-pole pieces.

[0011] In the above embodiments, dividing the complete first pole piece into multiple sub-pole pieces is beneficial for independently measuring the polarization current in the corresponding regions of each sub-pole piece, and having a gap between adjacent two sub-pole pieces can form electrical isolation between adjacent two sub-pole pieces, reducing the risk of internal short circuit caused by contact between adjacent two sub-pole pieces due to external impacts, vibrations or thermal expansions, etc.

[0012] In some embodiments, step S10 further includes: completely accommodating the N sub-pole pieces within the geometric range of the second pole piece.

[0013] In the above embodiments, completely accommodating the N sub-pole pieces within the geometric range of the second pole piece can help accurately control the effective reaction region between pole pieces of different polarities, reducing the occurrence of local overcharge or over-discharge phenomena.

[0014] In some embodiments, between step S20 and step S30, there is further step S21: applying a controllable pressure to the battery using an auxiliary tool to simulate the contact pressure between the first pole piece and the second pole piece.

[0015] In the above embodiments, applying pressure to the battery using an auxiliary tool makes the first pole piece, the second pole piece and other layers of the battery in a compressed state, thereby simulating the contact pressure environment between the pole pieces inside the battery; and this auxiliary tool has an adjustable pressure application function, which can adjust the applied pressure value according to different test requirements to simulate different contact pressure distribution situations caused by differences in the assembly process, stacking structure or packaging method of the actual battery, so as to more comprehensively analyze the battery polarization distribution characteristics caused by different reasons.

[0016] In some embodiments, step S21 further includes: correspondingly configuring a pressing plate of the auxiliary tool for each of the N sub-pole pieces, and applying pressure to the corresponding sub-pole piece and the second pole piece through the pressing plate.

[0017] In the above embodiment, by separately configuring a pressure plate in the auxiliary tool for each sub-pole sheet, and using the pressure plate to apply independently controllable pressure to the corresponding sub-pole sheet and the second pole sheet, the local force of the battery can be adjusted, thereby more accurately simulating the contact pressure distribution between the pole sheets in different areas inside the battery.

[0018] In some embodiments, the step S21 further includes: the pressure plate is provided with a pressure detection element, and the pressure applied by the pressure plate to the corresponding sub-pole piece and the second pole piece is detected by the pressure detection element.

[0019] In the above embodiment, a pressure detection element is preset in the pressure plate, and the pressure applied by the pressure plate to the corresponding sub-pole piece and the second pole piece is detected by the pressure detection element. The contact pressure between each sub-pole piece and the second pole piece can be monitored in real time, and the force of the pressure plate can be adjusted according to the pressure feedback from the pressure detection element to achieve precise control and feedback adjustment of the pressure, so that the pressure applied to the corresponding area of each sub-pole piece meets the preset requirements, thereby improving the controllability and repeatability of the experiment or test process and improving the accuracy of simulating the real internal pressure environment of the battery.

[0020] In some embodiments, the step S20 also includes: connecting the N sub-electrode sheets one-to-one through N first electrode lines, and each of the first electrode lines is provided with a current detection element, and the polarization current of the corresponding area of the sub-electrode sheet during the charging and discharging process of the battery is detected by the current detection element.

[0021] In the above embodiment, by configuring an independent first electrode line and a current detection element for each sub-pole sheet, the current distribution in the corresponding areas of different sub-pole sheets inside the battery can be monitored in real time and independently, thereby obtaining more detailed electrochemical behavior data. In addition, the polarization current information of the corresponding areas of each sub-pole sheet obtained by the current detection element can be used to analyze the local polarization phenomenon caused by factors such as contact pressure differences, uneven electrolyte distribution or interface side reactions, thereby providing a basis for optimizing the electrode structure design.

[0022] In some embodiments, the step S30 further includes: providing a control module in the charging and discharging device, the control module being electrically connected to the current detection element, and obtaining the polarization current signal sent by the current detection element through the control module.

[0023] In the above embodiments, the control module collects and processes the data of the current detection element, improving the real-time performance and accuracy of data collection; and the control module can analyze based on the received polarization current signal to obtain the polarization distribution characteristics of the battery, such as the reaction activity of each area of the battery, the change of interface impedance, and the degree of local polarization, which is helpful for studying complex electrochemical behaviors such as uneven current distribution and pressure difference inside the battery, etc.

[0024] In some embodiments, the step S30 further includes: setting an impedance module in the charge and discharge device, applying an alternating voltage or alternating current perturbation to the battery through the impedance module, and obtaining the polarization current corresponding to each area of each sub-electrode plate and the amplitude and phase of the total battery voltage through the impedance module, and calculating the impedance corresponding to each area of each sub-electrode plate.

[0025] In the above embodiments, an alternating voltage or alternating current perturbation is applied to the battery through the impedance module to simulate the alternating perturbation signal received during the operation of the battery, and the polarization current corresponding to each area of each sub-electrode plate and the amplitude and phase of the total battery voltage are obtained through the impedance module, so as to calculate the impedance corresponding to each area of each sub-electrode plate according to the polarization current corresponding to each area of each sub-electrode plate and the amplitude and phase of the total battery voltage, and further obtain the AC impedance spectrum of each local area inside the battery, thereby analyzing the differential behaviors of different areas in terms of electrochemical reaction kinetics, interface stability, etc., and obtaining the polarization distribution characteristics of the battery.

[0026] Some embodiments of the present application further provide a device for detecting the polarization distribution characteristics of a battery, which is used to implement the above method for detecting the polarization distribution characteristics of a battery. The detection device includes: a charge and discharge device, including a first electrode and a second electrode; and a battery, including a first electrode plate and a second electrode plate, the first electrode plate is divided into N sub-electrode plates, the N sub-electrode plates are connected in parallel and are connected to the first electrode through a busbar, and the second electrode plate is connected to the second electrode.

[0027] In the above embodiments, the complete first electrode plate is separated into a plurality of mutually electrically isolated sub-electrode plates, and the polarization current corresponding to each area of each sub-electrode plate is independently measured. Compared with the method of uniformly measuring the whole electrode plate, it can reduce the homogenization effect of the connected current collector inside the battery on the electrode current distribution, can more truly reflect the local polarization difference of different areas on the surface of the electrode plate, and the quantitative detection of the local polarization current of different areas on the surface of the electrode plate can obtain the difference information of each area on the surface of the electrode plate in terms of electrochemical reaction rate, electrolyte distribution, material activity, etc., providing data support for analyzing the polarization distribution characteristics of the battery, etc.

[0028] In some embodiments, a first tab is provided on each of the N sub-electrode plates.

[0029] In the above embodiments, by configuring an independent first tab for each sub - electrode tab, the current in the corresponding areas of each sub - electrode tab can be led out separately, reducing the current - sharing effect of the connected current collector on the current distribution, so as to accurately detect the local electrochemical reaction; in the parallel connection mode, each sub - electrode tab is connected to the circuit through an independent first tab, which helps to reduce the influence brought by the local resistance difference and the influence on the overall current distribution uniformity. Moreover, by obtaining the current distribution information in different areas inside the battery, it helps to analyze phenomena such as the polarization distribution characteristics of the battery.

[0030] In some embodiments, the battery further includes a separator disposed between the first electrode tab and the second electrode tab, and the N sub - electrode tabs are arranged at intervals in sequence along the length direction of the second electrode tab.

[0031] In the above embodiments, by sequentially laying and stacking the N sub - electrode tabs on the second electrode tab along the length direction of the second electrode tab, and arranging a separator between each sub - electrode tab and the second electrode tab to achieve electrical insulation isolation, a laminated - like electrode assembly structure is formed. This structure can increase the layout area of the active material within the limited space of the battery case, thereby improving the energy density per unit volume and per unit mass.

[0032] In some embodiments, the battery polarization distribution characteristic detection device further includes an auxiliary tool configured to apply a controllable pressure to the battery so as to press the N sub - electrode tabs against the second electrode tab.

[0033] In the above embodiments, an auxiliary tool is used to apply pressure to the battery, so that each layer such as the first electrode tab and the second electrode tab of the battery is in a compressed state, thereby simulating the contact pressure environment between the electrode tabs inside the battery; and this auxiliary tool has an adjustable pressure - applying function, which can adjust the applied pressure value according to different test requirements to simulate the different contact pressure distributions caused by differences in the assembly process, stacking structure or packaging method of the actual battery, so as to more comprehensively analyze the battery polarization distribution characteristics caused by different reasons.

[0034] In some embodiments, the auxiliary tool includes N pressing plates, and the N pressing plates are respectively arranged in one - to - one correspondence with the N sub - electrode tabs.

[0035] In the above embodiments, by separately configuring one pressing plate in the auxiliary tool for each sub - electrode tab, and using this pressing plate to apply an independent and controllable pressure to the corresponding sub - electrode tab and the second electrode tab, the local force of the battery can be adjusted, so as to accurately simulate the contact pressure distribution between the electrode tabs in different areas inside the battery. The degree of freedom of parameter regulation is relatively high, and it can be used to simulate the uneven contact pressure between planar electrodes caused by structural differences or assembly processes at different positions inside the battery, improving the accuracy and adaptability of the simulation experiment.

[0036] In some embodiments, the auxiliary tool includes: a base configured to carry the battery; and a pressing plate movably disposed on the base, the pressing plate being configured to move towards the base to apply a controllable pressure to the battery.

[0037] In the above embodiments, by adjusting the pressure applied by the pressing plate to the battery, the contact state between the electrode sheets under different assembly conditions during the actual use of the battery can be effectively simulated, providing an experimental basis for studying the electrode interface behavior, contact impedance change, etc. This auxiliary tool can reproduce the stress state during the battery packaging or module assembly process in a laboratory environment, making the measured electrochemical performance data closer to the real application scenario and improving the engineering reference value of the experimental results. The pressing plate can move relative to the base, facilitating the stable pressurization of the battery, thereby improving the accuracy and repeatability of the test results. By changing the displacement or loading force magnitude of the pressing plate, the performance evaluation of the battery under different pressure environments can be achieved, which helps to reveal the influence mechanism of pressure on the internal resistance, polarization behavior, and cycle life of the battery. The overall structure of this auxiliary tool is compact, simple, and easy to operate.

[0038] In some embodiments, the auxiliary tool further includes: a top plate, guide columns connecting the top plate and the base, the pressing plate being disposed between the top plate and the base and passing through the guide columns; and a thrust member disposed on the top plate and connected to the pressing plate through the top plate.

[0039] In the above embodiments, by providing the guide columns, a stable movement guiding path can be provided for the pressing plate, enabling the pressing plate to maintain parallelism and perpendicularity during the lifting process. The top plate and the base are firmly connected through the guide columns, forming a stable frame structure, which improves the overall mechanical strength and service life of the auxiliary tool; the thrust member is directly connected to the pressing plate and can be driven manually, electrically, pneumatically, or hydraulically. Combined with a control system, precise adjustment and dynamic control of the applied pressure can be achieved, meeting the requirements for simulating the contact pressure under different experimental conditions and improving the intelligent level and operation convenience of the equipment.

[0040] In some embodiments, the battery polarization distribution characteristic detection device further includes: N first electrode wires respectively connected to the N sub-electrode sheets in a one-to-one correspondence; and N current detection elements respectively disposed on the N first electrode wires in a one-to-one correspondence.

[0041] In the above embodiments, by configuring independent first electrode lines 50 and current detection elements for each sub-electrode plate, the current distribution in the corresponding areas of different sub-electrode plates inside the battery can be monitored in real time and independently, so as to obtain more refined electrochemical behavior data. Moreover, based on the polarization current information of the corresponding areas of each sub-electrode plate obtained by the current detection elements, the local polarization phenomenon caused by factors such as contact pressure difference, uneven electrolyte distribution or interfacial side reactions can be analyzed, providing a basis for optimizing the electrode structure design, and enabling more accurate judgment of the aging trend, capacity attenuation mechanism and failure position of the battery during the cycling process, etc.

[0042] In some embodiments, the charge and discharge device includes a control module, and the control module is electrically connected to the N current detection elements to obtain the polarization current signals sent by the N current detection elements.

[0043] In the above embodiments, by collecting and processing the data of the current detection elements through the control module, the real-time performance and accuracy of data collection are improved; and the control module can analyze the battery polarization distribution characteristics such as the reaction activity of each area of the battery, the change of interfacial impedance and the degree of local polarization based on the received polarization current signals, which helps to study complex electrochemical behaviors such as uneven current distribution and pressure difference inside the battery.

[0044] In some embodiments, the charge and discharge device further includes an impedance module, which is configured to apply an alternating voltage or alternating current perturbation to the battery, and is configured to calculate the impedance of the corresponding area of each sub-electrode plate according to the polarization current of the corresponding area of each sub-electrode plate and the amplitude and phase of the total voltage of the battery.

[0045] In the above embodiments, an alternating voltage perturbation or an alternating current perturbation is applied to the battery through the impedance module to simulate the alternating perturbation signal received by the battery during operation, and the polarization current of the corresponding area of each sub-electrode plate and the amplitude and phase of the total voltage of the battery are obtained through the impedance module. The impedance module also calculates the impedance of the corresponding area of each sub-electrode plate according to the polarization current of the corresponding area of each sub-electrode plate and the amplitude and phase of the total voltage of the battery, and then obtains the alternating current impedance spectrum of each local area inside the battery, so as to be used to analyze the differential behaviors of different areas in terms of electrochemical reaction kinetics, interfacial stability, etc., and obtain the battery polarization distribution characteristics.

[0046] Based on the above technical solutions, the present application has at least the following beneficial effects: In some embodiments, a complete first electrode tab is separated into a plurality of mutually electrically isolated sub - electrode tabs, and the polarization currents in the corresponding regions of each sub - electrode tab are measured independently. Compared with the method of uniformly measuring the overall electrode tab, it can reduce the homogenizing effect of the connected current collector inside the battery on the electrode current distribution, can more truly reflect the local polarization differences in different regions of the electrode tab surface, and through the quantitative detection of the local polarization currents in different regions of the electrode tab surface, the difference information in aspects such as the electrochemical reaction rate, electrolyte distribution, and material activity of each region on the electrode tab surface can be obtained, providing data support for analyzing the polarization distribution characteristics of the battery, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0048] Figure 1 is a schematic structural diagram of a vehicle disclosed in some embodiments of the present application; Figure 2 is an exploded structural diagram of a battery device disclosed in some embodiments of the present application; Figure 3 is an exploded structural diagram of a battery disclosed in some embodiments of the present application; Figure 4 is a schematic structural diagram of the stacking of a plurality of sub - electrode tabs obtained by dividing a first electrode tab and a second electrode tab disclosed in some embodiments of the present application; Figure 5 is a schematic diagram of a device for detecting the polarization distribution characteristics of a battery disclosed in some embodiments of the present application.

[0049] In the drawings, the drawings are not drawn to actual scale.

[0050] MARKING DESCRIPTION: 1 - First electrode tab; 11 - Sub - electrode tab; 12 - First tab; 2 - Second electrode tab; 21 - Second tab; 3 - Separator; 10 - Battery; 20 - Auxiliary tool; 201 - Base; 202 - Pressing plate; 203 - Top plate; 204 - Guide post; 205 - Thrust member; 207 - Pressure detection element; 30 - Charging and discharging device; 31 - First electrode; 32 - Second electrode; 40 - Current detection element; 50 - First electrode wire; 60 - Bus bar; 70 - Second electrode wire; 100 - Battery device; 101 - Box body; 101a - First box body; 101b - Second box body; 10a - Shell; 10b - End cover; 10c - Electrode assembly; 10d - Terminal; 10e - Explosion - proof valve; 200 - Vehicle; 210 - Axle; 220 - Wheel; 230 - Motor; 240 - Controller. Detailed implementation manners

[0051] The following further describes the implementation manners of the present application in detail with reference to the drawings and embodiments. The detailed descriptions and drawings of the following embodiments are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0052] In the description of the present application, it should be noted that unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0053] The orientation terms appearing in the following description are all the directions shown in the drawings, and do not limit the specific structure of the present application. In the description of the present application, it should also be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0054] With the development of the market situation, the application of battery devices is becoming increasingly widespread. At present, battery devices are not only applied to energy storage power systems such as hydraulic, thermal, wind, and solar power stations, but also widely applied to electric vehicles such as electric motorcycles and electric vehicles, as well as many other fields. Thus, it can be seen that battery devices can not only be used as the power supply for electrical devices, but also as the energy storage elements of various energy storage systems.

[0055] Refer to Figure 1 , in some embodiments, the battery device serves as the power supply for an electrical device, and the electrical device is a vehicle 200. The vehicle 200 can be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, a range-extended electric vehicle, etc.

[0056] The interior of the vehicle 200 is provided with a battery device 100, and the battery device 100 can be arranged at the bottom, head or tail of the vehicle 200. The battery device 100 can be used for power supply of the vehicle 200. For example, the battery device 100 can serve as the operating power source of the vehicle 200. The vehicle 200 may further include an axle 210, wheels 220 connected to the axle 210, as well as a motor 230 and a controller 240. The motor 230 is used to drive the axle 210 to rotate, and the controller 240 is used to control the operation of the motor 230. The battery device 100 can be used to provide electrical energy for the operation of the motor 230 and other components in the vehicle.

[0057] Therefore, the battery device 100 can not only serve as the operating power source of the vehicle 200, but also serve as the driving power source of the vehicle 200, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 200.

[0058] Reference Figure 2 , in some embodiments, the battery device 100 includes a box body 101 and batteries 10, and the batteries 10 are accommodated in the box body 101. The box body 101 includes a first box body 101a and a second box body 101b. The first box body 101a and the second box body 101b cover each other, and the first box body 101a and the second box body 101b jointly define an accommodation space for accommodating the batteries 10. The second box body 101b can be a hollow structure with one end open, and the first box body 101a can be a plate-like structure. The first box body 101a covers the open side of the second box body 101b so that the first box body 101a and the second box body 101b jointly define the accommodation space; the first box body 101a and the second box body 101b can also both be hollow structures with one side open, and the open side of the first box body 101a covers the open side of the second box body 101b. Of course, the box body 101 formed by the first box body 101a and the second box body 101b can be in various shapes, such as a cylinder or a cuboid, etc.

[0059] There can be multiple batteries 10, and the multiple batteries 10 can be connected in series, parallel or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple batteries 10. The multiple batteries 10 can be connected in series, parallel or in a mixed connection together, and then the whole formed by the multiple batteries 10 is accommodated in the box body 101. Of course, the battery device 100 can also be in the form that multiple batteries 10 are first connected in series, parallel or in a mixed connection to form battery modules, and then the multiple battery modules are connected in series, parallel or in a mixed connection to form a whole and are accommodated in the box body 101. The battery device 100 may further include other components. For example, the battery device 100 may further include a busbar assembly for realizing the electrical connection among the multiple batteries 10.

[0060] The battery 10 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery 10 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc.

[0061] Reference Figure 3 , in some embodiments, the battery 10 includes a housing 10a, an end cap 10b, and an electrode assembly 10c. The housing 10a is determined according to the shape after combining one or more electrode assemblies 10c. For example, the housing 10a can be a hollow cuboid, cube, or cylinder, and one of the faces of the housing 10a has an opening for placing one or more electrode assemblies 10c inside the housing 10a. For example, when the housing 10a is a hollow cuboid or cube, one of the flat surfaces of the housing 10a is the opening surface, that is, this plane does not have a housing wall and allows the inside and outside of the housing 10a to communicate. When the housing 10a is a hollow cylinder, the circular side surface of the housing 10a is the opening surface, that is, this circular side surface does not have a housing wall and allows the inside and outside of the housing 10a to communicate. The end cap 10b is connected to the housing 10a at the opening of the housing 10a to form a closed outer shell for placing the electrode assembly 10c.

[0062] The end cap 10b is basically in the shape of a flat plate, and two pole posts 10d are provided on the end cap 10b. The two pole posts 10d include a positive pole post and a negative pole post. An explosion-proof valve 10e can also be provided on the end cap 10b. When too much gas is generated in the battery 10 and the gas expands to increase the air pressure inside the housing 10a to exceed the preset value, the explosion-proof valve 10e can crack, causing the inside and outside of the housing 10a to communicate, and the gas is released outward through the crack of the explosion-proof valve 10e, thereby avoiding explosion.

[0063] In some embodiments, the electrode assembly 10c mainly includes two structural forms: a wound type and a stacked type. Among them, the wound type structure is formed by cutting the positive electrode sheet, negative electrode sheet, and separator into strips, and then laminating and winding them into a tight core in sequence. The stacked type structure is to stack the positive electrode sheet, negative electrode sheet, and separator layer by layer in sequence. Whether it is the wound type structure or the stacked type structure, the positive electrode sheet and the negative electrode sheet are isolated by the separator to prevent the positive electrode sheet and the negative electrode sheet from directly contacting and avoiding short circuit.

[0064] As the size of the electrode assembly 10c of commercial lithium-ion batteries gradually increases, the problem of uneven internal physical field distribution becomes increasingly prominent. During the operation of the battery, due to the unevenness of the surface temperature, stress, and electrolyte distribution of the electrode sheet, the electrochemical reaction rates at different positions will show differences. This difference in the electrochemical reaction rate leads to uneven polarization of the battery, which in turn causes loss of battery charge and discharge capacity and accelerated aging failure of local active materials, thus affecting the overall output performance and service life of the battery.

[0065] Therefore, the detection and analysis of the polarization distribution characteristics of the battery are crucial for the optimal design of the battery structure and materials. In some related technologies, the testing methods adopted can only characterize the overall electrochemical performance of the battery and cannot accurately measure the current distribution characteristics inside the battery. However, detecting the electrode current is a key technical means for evaluating the polarization distribution characteristics of the battery. By monitoring the actual current flow in the electrode area, local polarization phenomena and their causes can be more accurately identified, and then it can be used to improve the battery design, enhance the battery performance, and extend the service life.

[0066] Based on this, referring to Figure 4 and Figure 5 , some embodiments of the present application provide a method and device for detecting the polarization distribution characteristics of a battery, which can more accurately detect the current distribution on the surface of the electrode, realize the quantitative detection of the local polarization current in different regions on the electrode surface, and be used to more accurately analyze the polarization distribution characteristics of the battery.

[0067] In some embodiments, the method for detecting the polarization distribution characteristics of a battery includes the following steps. S10: Divide the first electrode 1 of the battery 10 into N sub-electrodes 11; where N is greater than or equal to 2, referring to Figure 4 ; S20: Connect the N sub-electrodes 11 in parallel, and then connect them in a current-collecting manner to the first electrode 31 of the charging and discharging device 30, and connect the second electrode 2 of the battery 10 to the second electrode 32 of the charging and discharging device 30, referring to Figure 5 ; and S30: Obtain the polarization current in the corresponding area of each of the N sub-electrodes 11 for analyzing the polarization distribution characteristics of the battery.

[0068] In the above embodiments, inside the battery 10, the first electrode 1 is separated into N sub-electrodes 11, and the N sub-electrodes 11 and the second electrode 2 of the battery 10 are isolated by a separator 3.

[0069] In the above embodiments, outside the battery 10, the N sub-electrodes 11 are first connected in parallel, and then connected in a current-collecting manner to the first electrode 31 of the charging and discharging device 30, and the second electrode 2 is connected to the second electrode 32 of the charging and discharging device 30. The polarity of the first electrode 31 is the same as that of the first electrode 1, and the polarity of the second electrode 32 is the same as that of the second electrode 2.

[0070] In some embodiments, the first electrode 1 is a positive electrode, and the second electrode 2 is a negative electrode. Or, the first electrode 1 is a negative electrode, and the second electrode 2 is a positive electrode.

[0071] In the above embodiments, by disposing a separator 3 between the first electrode tab 1 and the second electrode tab 2 with different polarities, the electrical insulation performance between the first electrode tab 1 and the second electrode tab 2 can be achieved, avoiding internal short circuits caused by direct contact and improving the safety and reliability of the battery.

[0072] In the above embodiments, the charge and discharge device 30 is configured to perform a charge or discharge operation on the battery 10 to simulate the working state of the battery 10 in actual applications. During the charging process, the charge and discharge device 30 inputs the energy of an external power source (such as a power grid or a DC power source) into the battery 10 in the form of a set current or voltage, so that the battery 10 stores electrical energy. During the discharging process, the charge and discharge device 30 absorbs the energy released by the battery and can use it for a load.

[0073] In the above embodiments, the complete first electrode tab 1 is separated into a plurality of electrically isolated sub-electrode tabs 11, and the polarization currents in the corresponding regions of the respective sub-electrode tabs 11 are independently measured. Compared with the method of uniformly measuring the entire electrode tab, the homogenizing effect of the connected current collector inside the battery on the electrode current distribution can be reduced, and the local polarization differences in different regions on the surface of the electrode tab can be more truly reflected. Moreover, through the quantitative detection of the local polarization currents in different regions on the surface of the electrode tab, difference information on aspects such as the electrochemical reaction rate, electrolyte distribution, and material activity in each region on the surface of the electrode tab can be obtained, providing data support for analyzing the polarization distribution characteristics of the battery, etc.; and based on the polarization characteristics of the respective sub-electrode tabs 11, performance weak regions can be identified to guide the improvement of the electrode structure, material distribution, and manufacturing process, and to improve the consistency and cycle life of the overall battery 10.

[0074] In the above embodiments, N is greater than or equal to 2. Optionally, N is equal to 3, 4, or 5, etc.

[0075] In some embodiments, step S10 further includes: sequentially and at intervals making N first electrode ears 12 along the length direction of the first electrode tab 1, and each of the divided sub-electrode tabs 11 has a first electrode ear 12.

[0076] In the above embodiments, by configuring an independent first electrode ear 12 for each sub-electrode tab 11, the currents in the corresponding regions of the respective sub-electrode tabs 11 can be separately led out, reducing the current equalizing effect of the connected current collector on the current distribution, thereby achieving accurate detection of local electrochemical reactions; in the parallel connection mode, the respective sub-electrode tabs 11 are connected to the circuit through independent first electrode ears 12, which helps to reduce the influence brought by local resistance differences and the influence on the overall current distribution uniformity. Moreover, through the obtained current distribution information in different regions inside the battery, it helps to analyze phenomena such as the polarization distribution characteristics of the battery, providing data support for battery health state assessment, dynamic equalization control, and intelligent management strategies, and improving the safety and service life of the battery system.

[0077] In some embodiments, in step S10, N sub-pole pieces 11 are tiled on the second pole piece 2 in sequence along the length direction of the second pole piece 2.

[0078] In the above embodiments, by sequentially tiling and stacking N sub-pole pieces 11 on the second pole piece 2 along the length direction of the second pole piece 2, and arranging a separator 3 between the N sub-pole pieces 11 and the second pole piece 2 to achieve electrical insulation isolation, a laminated electrode assembly structure is formed. This structure can increase the layout area of the active material within the limited space of the battery housing, thereby improving the energy density per unit volume and per unit mass.

[0079] In some embodiments, step S10 further includes: providing a gap between two adjacent sub-pole pieces 11.

[0080] In the above embodiments, dividing the complete first pole piece 1 into multiple sub-pole pieces 11 is conducive to independently measuring the polarization current in the corresponding regions of each sub-pole piece 11. And there is a gap between two adjacent sub-pole pieces 11, which can form electrical isolation between the two adjacent sub-pole pieces 11, reducing the risk of internal short circuit caused by contact between two adjacent sub-pole pieces 11 due to external impact, vibration or thermal expansion, etc.

[0081] In some embodiments, step S10 further includes: completely accommodating the N sub-pole pieces 11 within the geometric range of the second pole piece 2.

[0082] In the above embodiments, the sum of the dimensions of the N sub-pole pieces 11 in the length direction of the second pole piece 2 is less than the length of the second pole piece 2; the width of the sub-pole piece 11 is less than the width of the second pole piece 2; the total area of the N sub-pole pieces 11 is less than the total area of the second pole piece 2. The N sub-pole pieces 11 do not exceed the contour boundary of the second pole piece 2 in the length direction; the sub-pole piece 11 does not exceed the contour boundary of the second pole piece 2 in the width direction.

[0083] In the above embodiments, both the first pole piece 1 and the second pole piece 2 are long strip-shaped pole pieces. The length of the first pole piece 1 is less than the length of the second pole piece 2, and the width of the first pole piece 1 is less than the width of the second pole piece 2. The first pole piece 1 is sequentially divided into N sub-pole pieces 11 along the length direction, and the N sub-pole pieces 11 are laid on the second pole piece 2 at intervals along the length direction of the second pole piece 2, and one sub-pole piece 11 is laid in the width direction of the second pole piece 2.

[0084] In the above embodiments, completely accommodating the N sub-pole pieces 11 within the geometric range of the second pole piece 2 can help accurately control the effective reaction area between different polarity pole pieces and reduce the occurrence of local overcharge or over-discharge phenomena.

[0085] In some embodiments, between step S20 and step S30, there is also step S21: applying a controllable pressure to the battery 10 using the auxiliary tool 20 to simulate the contact pressure between the first electrode 1 and the second electrode 2.

[0086] In the above embodiment, applying a pressure to the battery 10 using the auxiliary tool 20 places each layer such as the first electrode 1 and the second electrode 2 of the battery 10 in a pressurized state, thereby simulating the contact pressure environment between the electrodes inside the battery 10; and the auxiliary tool 20 has an adjustable pressure application function and can adjust the applied pressure value according to different test requirements to simulate the different contact pressure distribution situations caused by differences in the assembly process, stacking structure, or packaging method of the actual battery, so as to more comprehensively analyze the battery polarization distribution characteristics caused by different reasons.

[0087] In some embodiments, step S21 further includes: configuring a pressing plate 202 of the auxiliary tool 20 corresponding to each of the N sub-electrodes 11 of the sub-electrodes 11, and applying a pressure to the corresponding sub-electrode 11 and the second electrode 2 through the pressing plate 202.

[0088] In the above embodiment, by separately configuring a pressing plate 202 in the auxiliary tool 20 for each sub-electrode 11 and using the pressing plate 202 to apply an independently controllable pressure to the corresponding sub-electrode 11 and the second electrode 2, the local force on the battery 10 can be adjusted, so as to more accurately simulate the contact pressure distribution situation between the electrodes in different regions inside the battery 10. The parameter control freedom is relatively high, and it can be used to simulate the uneven contact pressure between the planar electrodes caused by structural differences or assembly processes at different positions inside the battery, improving the accuracy and adaptability of the simulation experiment.

[0089] In some embodiments, step S21 further includes: the pressing plate 202 is provided with a pressure detection element 207, and the pressure applied by the pressing plate 202 to the corresponding sub-electrode 11 and the second electrode 2 is detected through the pressure detection element 207.

[0090] In the above embodiments, a pressure detection element 207 is pre - installed in the pressing plate 202. By detecting the pressure applied by the pressing plate 202 to the corresponding sub - electrode plate 11 and the second electrode plate 2 through the pressure detection element 207, the contact pressure between each sub - electrode plate 11 and the second electrode plate 2 can be monitored in real time, and the acting force of the pressing plate 202 can be adjusted according to the pressure feedback by the pressure detection element 207 to achieve precise control and feedback regulation of the pressure, so that the pressure applied to the corresponding area of each sub - electrode plate 11 meets the preset requirements, improving the controllability and repeatability of the experiment or test process, and enhancing the accuracy of simulating the internal pressure environment of a real battery; and by applying different pressure values to the corresponding areas of different sub - electrode plates 11, the effects of pressure changes on electrochemical properties such as interfacial impedance, lithium - ion transport rate, and polarization behavior can be systematically studied, providing a theoretical basis for optimizing battery design and assembly processes.

[0091] In some embodiments, the pressure detection element 207 includes a pressure sensor, etc.

[0092] In some embodiments, step S20 further includes: connecting N first electrode lines 50 to N sub - electrode plates 11 in one - to - one correspondence respectively, and a current detection element 40 is provided on each first electrode line 50. During the charge - discharge process of the battery 10, the polarization current of the corresponding area of the sub - electrode plate 11 is detected through the current detection element 40.

[0093] In the above embodiments, by configuring an independent first electrode line 50 and a current detection element 40 for each sub - electrode plate 11, the current distribution of the corresponding areas of different sub - electrode plates 11 inside the battery can be monitored in real time and independently, so as to obtain more refined electrochemical behavior data, and the local polarization phenomenon caused by factors such as contact pressure difference, uneven electrolyte distribution, or interfacial side reactions can be analyzed according to the polarization current information of the corresponding areas of each sub - electrode plate 11 obtained by the current detection element 40, providing a basis for optimizing the electrode structure design, and being able to more accurately judge the aging trend, capacity attenuation mechanism, and failure position of the battery during the cycling process, etc.

[0094] In the above embodiments, by integrating the current detection element 40 in multiple first electrode lines 50 connected in parallel outside the battery 10, quantitative monitoring of the current distribution of the corresponding areas of different sub - electrode plates 11 can be achieved; and there is no need to implant any sensing components inside the battery 10, and the intrinsic characteristics of the battery will not be affected by introducing sensors inside the battery.

[0095] In some embodiments, the current detection element 40 includes a current sensor, etc.

[0096] In some embodiments, step S30 further includes: a control module is provided in the charge and discharge device 30, the control module is electrically connected to the current detection element 40, and the control module obtains the polarization current signal sent by the current detection element 40.

[0097] In the above embodiments, the control module collects and processes the data of the current detection element 40, improving the real-time performance and accuracy of data collection; and the control module can analyze based on the received polarization current signal to obtain battery polarization distribution characteristics such as the reaction activity of each region of the battery, the change of interface impedance, and the degree of local polarization, which helps to study complex electrochemical behaviors such as uneven current distribution and pressure difference inside the battery.

[0098] In some embodiments, step S30 further includes: an impedance module is provided in the charge and discharge device 30, an alternating voltage perturbation or an alternating current perturbation is applied to the battery 10 through the impedance module, and the polarization current corresponding to each region of each sub-electrode plate 11 and the amplitude and phase of the total voltage of the battery 10 are obtained through the impedance module, and the impedance corresponding to each region of each sub-electrode plate 11 is calculated.

[0099] In the above embodiments, an alternating voltage or an alternating current perturbation is applied to the battery 10 through the impedance module to simulate the alternating perturbation signal received during the operation of the battery 10, and the polarization current corresponding to each region of each sub-electrode plate 11 and the amplitude and phase of the total voltage of the battery 10 are obtained through the impedance module, so as to calculate the impedance corresponding to each region of each sub-electrode plate 11 according to the polarization current corresponding to each region of each sub-electrode plate 11 and the amplitude and phase of the total voltage of the battery 10, and further obtain the AC impedance spectrum of each local region inside the battery, thereby analyzing the differential behaviors of different regions in terms of electrochemical reaction kinetics, interface stability, etc., and obtaining the battery polarization distribution characteristics.

[0100] Compared with the evaluation method that only relies on the overall battery voltage and current, the embodiments of the present application can obtain more refined regional impedance data, which helps to improve the evaluation accuracy of key parameters such as the battery health state and the degree of capacity attenuation.

[0101] Reference Figure 4 and Figure 5 In some embodiments of the present application, a device for detecting battery polarization distribution characteristics is further provided to implement the above-mentioned method for detecting battery polarization distribution characteristics.

[0102] In some embodiments, the device for detecting battery polarization distribution characteristics includes: A charge and discharge device 30, including a first electrode 31 and a second electrode 32; and The battery 10 includes a first electrode plate 1 and a second electrode plate 2. The first electrode plate 1 is divided into N sub-electrode plates 11, and the N sub-electrode plates 11 are connected in parallel and are connected in a current collecting manner to the first electrode 31. The second electrode plate 2 is connected to the second electrode 32.

[0103] In the above embodiment, the charge and discharge device 30 is configured to perform a charge or discharge operation on the battery 10 to simulate the working state of the battery 10 in actual application. During the charging process, the charge and discharge device 30 inputs the energy of an external power source (such as a power grid or a DC power source) into the battery 10 in the form of a set current or voltage, so that the battery 10 stores electrical energy. During the discharging process, the charge and discharge device 30 absorbs the energy released by the battery 10 and can use it for a load.

[0104] In the above embodiment, the complete first electrode plate 1 is separated into a plurality of mutually electrically isolated sub-electrode plates 11, which can independently measure the polarization current in the corresponding regions of each sub-electrode plate 11. Compared with the method of uniformly measuring the overall electrode plate, it can reduce the homogenization effect of the connected current collector inside the battery on the electrode current distribution, can more truly reflect the local polarization differences in different regions of the electrode plate surface, and the quantitative detection of the local polarization current in different regions of the electrode plate surface can obtain the difference information in aspects such as the electrochemical reaction rate, electrolyte distribution, and material activity of each region on the electrode plate surface, providing data support for analyzing the polarization distribution characteristics of the battery, etc.; and based on the polarization characteristics of each sub-electrode plate 11, weak performance regions can be identified to guide the improvement of the electrode structure, material distribution, and manufacturing process, and improve the consistency and cycle life of the overall battery 10.

[0105] In some embodiments, a first tab 12 is provided on each of the N sub-electrode plates 11.

[0106] In the above embodiment, by configuring an independent first tab 12 for each sub-electrode plate 11, the currents in the corresponding regions of each sub-electrode plate 11 can be separately led out, reducing the current equalizing effect of the connected current collector on the current distribution, thereby realizing the accurate detection of local electrochemical reactions; in the parallel connection mode, each sub-electrode plate 11 is connected to the circuit through an independent first tab 12, which helps to reduce the influence brought by local resistance differences and the influence caused by the overall current distribution uniformity, and can obtain the current distribution information in different regions inside the battery, which helps to analyze phenomena such as polarization non-uniformity and material aging, providing data support for battery health state assessment, dynamic balancing control, and intelligent management strategies, and improving the safety and service life of the battery system.

[0107] In some embodiments, the battery 10 further includes a separator 3. The separator 3 is disposed between the first electrode plate 1 and the second electrode plate 2, and the N sub-electrode plates 11 are arranged at intervals in the length direction of the second electrode plate 2.

[0108] In the above embodiments, by sequentially laying and stacking N sub-pole pieces 11 along the length direction of the second pole piece 2 and arranging a separator 3 between each sub-pole piece 11 and the second pole piece 2 to achieve electrical insulation isolation, a laminated electrode assembly structure is formed. This structure can increase the layout area of the active material within the limited space of the battery case, thereby improving the energy density per unit volume and per unit mass.

[0109] In the above embodiments, dividing the complete first pole piece 1 into multiple sub-pole pieces 11 is beneficial for independently measuring the polarization current in the corresponding regions of each sub-pole piece 11. Moreover, there is a gap between two adjacent sub-pole pieces 11, which can form electrical isolation between the two adjacent sub-pole pieces 11, reducing the risk of internal short circuit caused by contact between two adjacent sub-pole pieces 11 due to external impacts, vibrations, or thermal expansion.

[0110] In some embodiments, the N sub-pole pieces 11 are completely accommodated within the geometric range of the second pole piece 2.

[0111] In the above embodiments, having the N sub-pole pieces 11 completely accommodated within the geometric range of the second pole piece 2 can help accurately control the effective reaction area between different polarity pole pieces and reduce the occurrence of local overcharging or over-discharging phenomena.

[0112] In some embodiments, the second pole piece 2 and the separator 3 are not divided, and both the second pole piece 2 and the separator 3 are of an integral structure.

[0113] In some embodiments, the battery polarization distribution characteristic detection device further includes an auxiliary tool 20, which is configured to apply a controllable pressure to the battery 10 to press the N sub-pole pieces 11 against the second pole piece 2.

[0114] In the above embodiments, using the auxiliary tool 20 to apply pressure to the battery 10 makes the layers such as the first pole piece 1 and the second pole piece 2 of the battery 10 in a compressed state, thereby simulating the contact pressure environment between the pole pieces inside the battery 10. And the auxiliary tool 20 has an adjustable pressure application function, which can adjust the applied pressure value according to different test requirements to simulate the different contact pressure distributions caused by differences in the assembly process, stacking structure, or packaging method of the actual battery, so as to more comprehensively analyze the battery polarization distribution characteristics caused by different reasons.

[0115] The auxiliary tool 20 includes N pressing plates 202, and the N pressing plates 202 are respectively arranged in one-to-one correspondence with the N sub-pole pieces 11.

[0116] In the above embodiments, by separately configuring one pressing plate 202 in the auxiliary tool 20 for each sub - electrode plate 11, and using the pressing plate 202 to apply independently controllable pressure to the corresponding sub - electrode plate 11 and the second electrode plate 2, the local force on the battery 10 can be adjusted, so as to accurately simulate the contact pressure distribution between the electrode plates in different regions inside the battery 10. The degree of freedom of parameter regulation is relatively high, and it can be used to simulate the uneven contact pressure between planar electrode plates caused by structural differences or assembly processes at different positions inside the battery, improving the accuracy and adaptability of the simulation experiment.

[0117] In some embodiments, the auxiliary tool 20 includes: A base 201 configured to carry the battery 10; and A pressing plate 202 movably arranged on the base 201, and the pressing plate 202 is configured to move towards the base 201 to apply controllable pressure to the battery 10.

[0118] In the above embodiments, by adjusting the pressure applied by the pressing plate 202 to the battery 10, the contact state between the electrode plates under different assembly conditions during the actual use of the battery can be effectively simulated, providing an experimental basis for studying the electrode - interface behavior, contact - impedance change, etc. The auxiliary tool 20 can reproduce the stress state during the battery packaging or module assembly process in a laboratory environment, making the measured electrochemical performance data closer to the real application scenario and improving the engineering reference value of the experimental results. The pressing plate 202 can move relative to the base 201, facilitating the realization of stable pressurization of the battery 10, thereby improving the accuracy and repeatability of the test results. By changing the displacement or the magnitude of the loading force of the pressing plate 202, the performance evaluation of the battery 10 under different pressure environments can be realized, which helps to reveal the influence mechanism of pressure on the internal resistance, polarization behavior and cycle life of the battery. The overall structure of the auxiliary tool 20 is compact, simple and easy to operate.

[0119] In some embodiments, the auxiliary tool 20 further includes: A top plate 203, A guide post 204 connecting the top plate 203 and the base 201, the pressing plate 202 is arranged between the top plate 203 and the base 201 and passes through the guide post 204; and A thrust member 205 arranged on the top plate 203 and passing through the top plate 203 to be connected to the pressing plate 202.

[0120] In the above embodiments, a plurality of guide posts 204 are provided between the top plate 203 and the base 201. The top plate 203 and the base 201 are connected by the guide posts 204. The pressing plate 202 is disposed between the top plate 203 and the base 201 and can slide along the guide posts 204. The thrust member 205 is disposed on the top plate 203 and passes through the top plate 203 to be connected to the pressing plate 202, and is used to drive the pressing plate 202 to move towards the base 201 so as to apply pressure to the battery 10.

[0121] In the above embodiments, by providing the guide posts 204, a stable movement guiding path can be provided for the pressing plate 202, so that the pressing plate 202 maintains parallelism and perpendicularity during the lifting process, avoiding uneven pressure distribution caused by offset or tilt, thereby improving the repeatability and reliability of the test data. The top plate 203 and the base 201 are firmly connected by the guide posts 204 to form a stable frame structure, which can effectively withstand the loading force applied by the thrust member 205, prevent the test results from being affected by structural deformation, and at the same time improve the overall mechanical strength and service life of the auxiliary tool 20. The thrust member 205 is directly connected to the pressing plate 202 and can be driven manually, electrically, pneumatically or hydraulically. Combined with the control system, precise adjustment and dynamic control of the applied pressure can be realized, meeting the requirements for simulating the contact pressure under different experimental conditions, and improving the intelligent level and operation convenience of the equipment.

[0122] In some embodiments, the pressing plate 202 is a square plate, and guide posts 204 are respectively passed through the four corners of the pressing plate 202. The pressing plate 202 moves towards or away from the base 201 under the guiding action of the four guide posts 204.

[0123] In some embodiments, a pressure detection element 207 is provided on the pressing plate 202. The pressure detection element 207 is used to detect the acting force applied by the pressing plate 202 to the battery 10, so as to adjust the acting force applied by the pressing plate 202 to the battery 10 according to the detection requirements, improve the accuracy of simulating the contact state of the electrode sheet, and is applicable to studying the influence of different pressures on the electrochemical performance of the battery.

[0124] In some embodiments, the battery polarization distribution characteristic detection device further includes: N first electrode lines 50, which are respectively and correspondingly connected to N sub-electrode sheets 11; and N current detection elements 40, which are respectively and correspondingly disposed on the N first electrode lines 50.

[0125] In the above embodiments, by configuring independent first electrode lines 50 and current detection elements 40 for each sub-electrode tab 11, the current distribution in the corresponding regions of different sub-electrode tabs 11 inside the battery can be monitored in real time and independently, so as to obtain more refined electrochemical behavior data. Moreover, based on the polarization current information of the corresponding regions of each sub-electrode tab 11 obtained by the current detection element 40, the local polarization phenomenon caused by factors such as contact pressure difference, uneven electrolyte distribution or interfacial side reactions can be analyzed, providing a basis for optimizing the electrode structure design, and enabling a more accurate judgment of the aging trend, capacity attenuation mechanism and failure position of the battery during the cycling process, etc.

[0126] In the above embodiments, by integrating the current detection element 40 in multiple first electrode lines 50 connected in parallel outside the battery 10, quantitative monitoring of the current distribution in the corresponding regions of different sub-electrode tabs 11 can be achieved; and there is no need to implant any sensing components inside the battery 10, and the introduction of internal sensors will not affect the intrinsic characteristics of the battery.

[0127] In the above embodiments, the first electrode line 50 is connected to the first tab 12 of the sub-electrode tab 11.

[0128] In some embodiments, the battery polarization distribution characteristic detection device further includes a bus bar 60. N first electrode lines 50 are connected to the first end of the bus bar 60, and the second end of the bus bar 60 is connected to the first electrode 31 of the charge and discharge device 30.

[0129] In some embodiments, the battery polarization distribution characteristic detection device further includes a second electrode line 70. The second electrode line 70 is connected to the second electrode tab 2 and the second electrode 32 of the charge and discharge device 30. Specifically, the second electrode line 70 is connected to the second tab 21 of the second electrode tab 2 and the second electrode 32 of the charge and discharge device 30.

[0130] In some embodiments, the charge and discharge device 30 includes a control module. The control module is electrically connected to N current detection elements 40 to obtain the polarization current signals sent by the N current detection elements 40.

[0131] In the above embodiments, by collecting and processing the data of the current detection element 40 through the control module, the real-time performance and accuracy of data collection are improved; and the control module can analyze the battery polarization distribution characteristics such as the reaction activity, interfacial impedance change and local polarization degree of each region of the battery based on the received polarization current signals, which helps to study complex electrochemical behaviors such as uneven current distribution and pressure difference inside the battery, etc.

[0132] In some embodiments, the charge and discharge device 30 further includes an impedance module configured to apply an alternating voltage perturbation or an alternating current perturbation to the battery 10, and the impedance module is further configured to calculate the impedance of the corresponding region of each sub-electrode tab 11 according to the polarization current of the corresponding region of each sub-electrode tab 11 and the amplitude and phase of the total voltage of the battery 10.

[0133] In the above embodiments, an alternating voltage perturbation or an alternating current perturbation is applied to the battery 10 through the impedance module to simulate the alternating perturbation signal received during the operation of the battery 10, and the polarization current of the corresponding region of each sub-electrode tab 11 and the amplitude and phase of the total voltage of the battery 10 are obtained through the impedance module. The impedance module also calculates the impedance of the corresponding region of each sub-electrode tab 11 according to the polarization current of the corresponding region of each sub-electrode tab 11 and the amplitude and phase of the total voltage of the battery 10, and then obtains the AC impedance spectra of each local region inside the battery, so as to analyze the differential behaviors of different regions in aspects such as electrochemistry reaction kinetics and interface stability, and obtain the battery polarization distribution characteristics.

[0134] Compared with the evaluation method that only relies on the overall battery voltage and current, the embodiments of the present application can obtain more refined regional impedance data, which helps to improve the evaluation accuracy of key parameters such as the battery health state and the degree of capacity attenuation.

[0135] In some embodiments, the battery 10 includes a stacked battery. Optionally, the battery 10 includes a stacked lithium battery.

[0136] The following Figure 4 and Figure 5 will be used to describe in detail some specific embodiments of the battery polarization distribution characteristic detection device. In this specific embodiment, the first electrode tab 1 is a positive electrode tab, and the second electrode tab 2 is a negative electrode tab.

[0137] Before measuring the current distribution characteristics of the stacked battery, in order to prevent the highly conductive connected current collector from equalizing the reaction current distribution on the electrode surface, the first electrode tab 1 of the battery 10 is pre-divided. The specific method is to process a plurality of first electrode tabs 12 on the long side of the first electrode tab 1, and divide the first electrode tab 1 into N sub-electrode tabs 11 along the length direction, where each sub-electrode tab 11 corresponds to a current detection partition, each sub-electrode tab 11 contains at least one first electrode tab 12, and the number N of sub-electrode tabs 11 is greater than or equal to 2.

[0138] During the stacking process of the battery 10, the sub-electrode tabs 11 are laid flat in sequence along the length direction of the second electrode tab 2, with gaps between the sub-electrode tabs 11 and no contact with each other. The first electrode tab 1 and the second electrode tab 2 are separated by a separator 3; wherein, neither the second electrode tab 2 nor the separator 3 is divided, and the total length and total area of the first electrode tab 1 are both smaller than the total length and total area of the second electrode tab 2.

[0139] The above laminated battery is pressed using an integral auxiliary tool or a distributed auxiliary tool. Among them, the pressing plate area and the base area of the integral auxiliary tool are both larger than the total area of the first electrode plate 1. The distributed auxiliary tool includes a plurality of parallel movable pressing plates 202, the area of each movable pressing plate 202 is larger than the area of the sub-electrode plate 11, a pressure detection element 207 is arranged inside the pressing plate 202, the strokes of the respective movable pressing plates 202 can be independently adjusted, and each movable pressing plate 202 covers a sub-electrode plate 11 when clamping the battery 10. The distributed auxiliary tool can be used to simulate the situation of uneven polarization caused by uneven contact pressure between the electrodes of the battery 10.

[0140] The battery polarization distribution characteristic detection device further includes a plurality of first electrode lines 50 connected in parallel and at least one second electrode line 70. The second electrode tab 21 led out from the second electrode plate 2 is connected to the second electrode line 70, and the second electrode line 70 is connected to the second electrode 32 of the charge and discharge device 30. Each first electrode tab 12 led out from each sub-electrode plate 11 is respectively connected to a first electrode line 50; all the first electrode lines 50 are connected in parallel to the bus line 60, and the bus line 60 is connected to the first electrode 31 of the charge and discharge device 30. Among them, each first electrode line 50 is provided with a current detection element 40, and the current detection element 40 is used to detect the polarization current of the corresponding area of each sub-electrode plate 11 during the charge and discharge process of the battery 10.

[0141] The charge and discharge device 30 is used to charge and discharge the laminated battery 10 and simultaneously obtain the current distribution of the battery 10.

[0142] The charge and discharge device 30 is further used to apply an alternating voltage disturbance or an alternating current disturbance to the battery 10, and can simultaneously obtain the branch current of each first electrode line 50 and the amplitude and phase of the total voltage of the battery 10. Among them, the total voltage of the battery 10 is the voltage between the second electrode tab 21 of the battery 10 and the first electrode tab 12 of any sub-electrode plate 11. The impedance module of the charge and discharge device 30 can calculate the impedance of each parallel branch according to the obtained voltage data and current data, that is, the partition AC impedance of the laminated battery 10.

[0143] In the embodiment of the present application, the segmentation of the electrode plates of the battery 10 can avoid the uniformization of the electrode current distribution by the connected current collector inside the battery, so as to effectively extract the polarization current distribution information on the electrode surface; the battery polarization distribution characteristic detection method and device provided by the embodiment of the present application have beneficial effects such as low cost, simple operation, reliable test results, and strong scalability.

[0144] Based on the above embodiments of the present application, without explicit negation or conflict, the technical features of one embodiment can be beneficially combined with one or more other embodiments.

[0145] Although the present application has been described with reference to preferred embodiments, various modifications can be made thereto and components thereof can be replaced with equivalents without departing from the scope of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for detecting the polarization distribution characteristics of a battery, characterized in that, including the following steps, S10: Divide the first electrode sheet (1) of the battery (10) into N sub-electrode sheets (11); where N is greater than or equal to 2; S20: Connect the N sub-electrode sheets (11) in parallel, and then connect them in parallel to the first electrode (31) of the charge and discharge device (30), and connect the second electrode sheet (2) of the battery (10) to the second electrode (32) of the charge and discharge device (30); and S30: Obtain the polarization current of each corresponding area of the N sub-electrode sheets (11) for analyzing the polarization distribution characteristics of the battery.

2. The method for detecting the battery polarization distribution characteristics according to claim 1, wherein The step S10 further includes: successively and at intervals make N first electrode tabs (12) along the length direction of the first electrode sheet (1), and each divided sub-electrode sheet (11) has a first electrode tab (12).

3. The battery polarization distribution characteristic detection method according to claim 1, wherein The step S10 further includes: lay the N sub-electrode sheets (11) successively along the length direction of the second electrode sheet (2) on the second electrode sheet (2).

4. The method for detecting the battery polarization distribution characteristics according to claim 3, wherein The step S10 further includes: having a gap between two adjacent sub-electrode sheets (11).

5. The method for detecting the battery polarization distribution characteristics according to claim 3, characterized in that The step S10 further includes: completely accommodating the N sub-electrode sheets (11) within the geometric range of the second electrode sheet (2).

6. The method for detecting the battery polarization distribution characteristics according to claim 3, wherein, Between the step S20 and the step S30, there is also a step S21: Use an auxiliary tool (20) to apply a controllable pressure to the battery (10) to simulate the contact pressure between the first electrode sheet (1) and the second electrode sheet (2).

7. The method for detecting the battery polarization distribution characteristics according to claim 6, wherein The step S21 further includes: correspondingly configure a pressing plate (202) of the auxiliary tool (20) for each of the N sub-electrode sheets (11), and apply pressure to the corresponding sub-electrode sheet (11) and the second electrode sheet (2) through the pressing plate (202).

8. The method for detecting the battery polarization distribution characteristics according to claim 7, wherein The step S21 further includes: the pressing plate (202) is provided with a pressure detection element (207), and the pressure applied by the pressing plate (202) to the corresponding sub-electrode sheet (11) and the second electrode sheet (2) is detected through the pressure detection element (207).

9. The battery polarization distribution characteristic detection method according to claim 1, wherein The step S20 further includes: respectively connect the N sub-electrode sheets (11) one by one through N first electrode wires (50), and a current detection element (40) is provided on each of the first electrode wires (50), and the polarization current of the corresponding area of the sub-electrode sheet (11) during the charge and discharge process of the battery (10) is detected through the current detection element (40).

10. The method for detecting the battery polarization distribution characteristics according to claim 9, wherein The step S30 further includes: setting a control module in the charge and discharge device (30), the control module is electrically connected to the current detection element (40), and the polarization current signal sent by the current detection element (40) is obtained through the control module.

11. The method for detecting the battery polarization distribution characteristics according to claim 1, characterized in that The step S30 further includes: setting an impedance module in the charge and discharge device (30), applying an alternating voltage or alternating current perturbation to the battery (10) through the impedance module, and obtaining the polarization current of each corresponding area of each sub-electrode sheet (11) and the amplitude and phase of the total voltage of the battery (10) through the impedance module, and calculating the impedance of each corresponding area of each sub-electrode sheet (11).

12. A device for detecting the polarization distribution characteristics of a battery, characterized in that, For implementing the battery polarization distribution characteristic detection method according to any one of claims 1 to 11, the detection device includes: A charge and discharge device (30), including a first electrode (31) and a second electrode (32); and A battery (10), including a first electrode plate (1) and a second electrode plate (2), the first electrode plate (1) is divided into N sub-electrode plates (11), the N sub-electrode plates (11) are connected in parallel and are connected in a current collecting manner to the first electrode (31), and the second electrode plate (2) is connected to the second electrode (32).

13. The battery polarization distribution characteristic detection device according to claim 12, wherein, A first tab (12) is provided on each of the N sub-electrode plates (11).

14. The battery polarization distribution characteristic detection device according to claim 12, characterized in that, The battery (10) further includes a separator (3), the separator (3) is disposed between the first electrode plate (1) and the second electrode plate (2), and the N sub-electrode plates (11) are arranged at intervals in sequence along the length direction of the second electrode plate (2).

15. The battery polarization distribution characteristic detection device according to claim 12, wherein It further includes an auxiliary tool (20), and the auxiliary tool (20) is configured to apply a controllable pressure to the battery (10) so that the N sub-electrode plates (11) are pressed against the second electrode plate (2).

16. The battery polarization distribution characteristic detection device according to claim 15, wherein The auxiliary tool (20) includes N pressing plates (202), and the N pressing plates (202) are respectively arranged in one-to-one correspondence with the N sub-electrode plates (11).

17. The battery polarization distribution characteristic detection device according to claim 15, characterized in that, The auxiliary tool (20) includes: A base (201), configured to carry the battery (10); and A pressing plate (202), movably disposed on the base (201), and the pressing plate (202) is configured to move towards the base (201) to apply a controllable pressure to the battery (10).

18. The battery polarization distribution characteristic detection device according to claim 17, wherein The auxiliary tool (20) further includes: A top plate (203), A guide post (204), connecting the top plate (203) and the base (201), the pressing plate (202) is disposed between the top plate (203) and the base (201) and passes through the guide post (204); and A thrust member (205), disposed on the top plate (203) and connected to the pressing plate (202) through the top plate (203).

19. The battery polarization distribution characteristic detection device according to claim 12, characterized in that, It further includes: N first electrode wires (50), respectively connected to the N sub-electrode plates (11) in one-to-one correspondence; And N current detection elements (40), respectively disposed on the N first electrode wires (50) in one-to-one correspondence.

20. The battery polarization distribution characteristic detection device according to claim 19, characterized in that, The charge and discharge device (30) includes a control module, and the control module is electrically connected to the N current detection elements (40) to obtain the polarization current signals sent by the N current detection elements (40).

21. The battery polarization distribution characteristic detection device according to claim 12, characterized in that The charge and discharge device (30) further includes an impedance module, and the impedance module is configured to apply an alternating voltage or alternating current perturbation to the battery (10), and is configured to calculate the impedance of the corresponding region of each sub-electrode plate (11) according to the polarization current of the corresponding region of each sub-electrode plate (11) and the amplitude and phase of the total voltage of the battery (10).

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