Battery polarization distribution characteristic detection method and device

Abstract

The embodiment of the application provides a battery polarization distribution characteristic detection method and device, the battery polarization distribution characteristic detection method comprises the following steps, S10: the first pole piece of the battery is divided into N sub-pole pieces; wherein, N is greater than or equal to 2; S20: the N sub-pole pieces are connected in parallel, then are connected in parallel connection on the first electrode of the charge-discharge equipment, the second pole piece of the battery is connected on the second electrode of the charge-discharge equipment; and S30: the polarization current of each sub-pole piece corresponding area of the N sub-pole pieces is acquired, for analyzing the battery polarization distribution characteristic. The complete first pole piece is divided into a plurality of mutually electrically isolated sub-pole pieces, and the polarization current of the area corresponding to each sub-pole piece is independently measured, the homogenization effect of the communication current collector in the battery on the electrode current distribution can be reduced, and the local polarization difference of the different areas of the pole piece surface can be more truly reflected, providing data support for analyzing the battery polarization distribution characteristic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery polarization distribution characteristic detection method and device. BACKGROUND

[0002] In some related technologies, during the working process of a battery, the non-uniformity of battery polarization exists, which affects the output performance and service life of the battery as a whole. SUMMARY

[0003] Some embodiments of the present application provide a battery polarization distribution characteristic detection method and device for optimizing battery performance.

[0004] Some embodiments of the present application provide a battery polarization distribution characteristic detection method, comprising 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 and then connecting them in parallel to a first electrode of a charge and discharge device, and connecting a second pole piece of the battery to a second electrode of the charge and discharge device; and S30: obtaining the polarization current of each sub-pole piece corresponding area of the N sub-pole pieces for analyzing the battery polarization distribution characteristic.

[0005] In the above-mentioned embodiments, the complete first pole piece is divided into a plurality of mutually electrically isolated sub-pole pieces, and the polarization current of each sub-pole piece corresponding area is independently measured. Compared with the way of uniformly measuring the whole pole piece, the homogenization effect of the connected current collector on the electrode current distribution in the battery can be reduced, the local polarization difference of different areas on the pole piece surface can be more truly reflected, and the quantitative detection of the local polarization current of different areas on the pole piece surface can obtain the difference information of each area on the pole piece surface in terms of electrochemical reaction rate, electrolyte distribution, material activity, etc., providing data support for analyzing the battery polarization distribution characteristic.

[0006] In some embodiments, the step S10 further comprises: sequentially spacing N first pole lugs along the length direction of the first pole piece, and each sub-pole piece after division has one first pole lug.

[0007] In the above-mentioned embodiments, by configuring an independent first pole lug for each sub-pole piece, the current of each sub-pole piece corresponding area can be respectively led out, reducing the current distribution homogenization effect of the connected current collector, so as to realize accurate detection of local electrochemical reaction; in the parallel connection mode, each sub-pole piece is connected to the circuit through an independent first pole lug, which helps to reduce the influence of local resistance difference and the influence of the uniformity of the overall current distribution, and through the obtained current distribution information of different areas inside the battery, it is helpful to analyze the battery polarization distribution characteristic and other phenomena.

[0008] In some embodiments, the step S10 further comprises: sequentially laying the N sub-poles on the second pole along the length direction of the second pole.

[0009] In the above embodiments, by sequentially laying the N sub-poles on the second pole along the length direction of the second pole, and setting a diaphragm between the N sub-poles and the second pole to achieve electrical insulation, a laminated electrode assembly structure is formed, which can increase the arrangement area of active materials in a limited battery shell space, thereby improving the energy density per unit volume and per unit mass.

[0010] In some embodiments, the step S10 further comprises: having a gap between the two adjacent sub-poles.

[0011] In the above embodiments, the complete first pole is divided into multiple sub-poles, which is conducive to independent measurement of the polarization current of the corresponding area of each sub-pole, and the gap between the two adjacent sub-poles can form electrical isolation between the two adjacent sub-poles, reducing the risk of internal short circuit caused by contact between the two adjacent sub-poles due to external impact, vibration or thermal expansion, etc.

[0012] In some embodiments, the step S10 further comprises: completely accommodating the N sub-poles in the geometric range of the second pole.

[0013] In the above embodiments, completely accommodating the N sub-poles in the geometric range of the second pole can help to accurately control the effective reaction area between different polarity poles and reduce the occurrence of local overcharge or overdischarge.

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

[0015] In the above embodiments, the auxiliary tool is used to apply pressure to the battery, so that each layer of the battery, such as the first pole and the second pole, is in a state of being under pressure, thereby simulating the contact pressure environment between the poles inside the battery; and the auxiliary tool has an adjustable pressure applying function, which can adjust the applied pressure value according to different test requirements, so as to simulate different contact pressure distribution caused by differences in assembly process, stacking structure or packaging method of the actual battery, thereby more comprehensively analyzing the battery polarization distribution characteristics caused by different reasons.

[0016] In some embodiments, the step S21 further comprises: corresponding to each sub-pole of the N sub-poles, configuring a pressure plate of the auxiliary tool, and applying pressure to the corresponding sub-pole and the second pole through the pressure plate.

[0017] In the above embodiment, by configuring one pressing plate in the auxiliary tool for each sub-pole piece, and using the pressing plate to apply an independently controllable pressure on the corresponding sub-pole piece and the second pole piece, the local stress of the battery can be adjusted, so that the contact pressure distribution between the pole pieces in different regions inside the battery can be more accurately simulated.

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

[0019] In the above embodiment, the pressure detection element is pre-installed in the pressing plate, the contact pressure between each sub-pole piece and the second pole piece can be monitored in real time through the pressure detection element, and the force of the pressing plate can be adjusted according to the pressure feedback by the pressure detection element, so as to realize accurate control and feedback adjustment of the pressure, so that the pressure applied by each sub-pole piece in the corresponding region meets the preset requirements, the controllability and repeatability of the experiment or test process are improved, and the accuracy of simulating the internal pressure environment of the real battery is improved.

[0020] In some embodiments, the step S20 further includes that N first electrode lines are respectively connected to the N sub-pole pieces in one-to-one correspondence, and each first electrode line is provided with a current detection element, and the polarization current of the corresponding region of the sub-pole piece in the battery charging and discharging process is detected through 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 piece, the current distribution in the corresponding region of different sub-pole pieces inside the battery can be monitored in real time and independently, so that more detailed electrochemical behavior data can be obtained, and the local polarization phenomenon caused by factors such as contact pressure difference, uneven distribution of electrolyte, or interface side reaction can be analyzed according to the polarization current information of the corresponding region of each sub-pole piece obtained by the current detection element, so as to provide a basis for optimizing the electrode structure design.

[0022] In some embodiments, the step S30 further includes that a control module is arranged in the charging and discharging device, the control module is electrically connected with the current detection element, and the polarization current signal sent by the current detection element is acquired through the control module.

[0023] In the above embodiment, the data of the current detection element is collected and processed by the control module, improving the real-time and accuracy of data collection; and the control module can analyze the received polarization current signal to obtain the battery polarization distribution characteristics such as the reaction activity of each region of the battery, the interface impedance change, and the local polarization degree, which is helpful to study the complex electrochemical behaviors such as uneven current distribution and pressure difference in the battery.

[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 disturbance to the battery through the impedance module, and obtaining the amplitude and phase of the polarization current of each sub-tab corresponding region and the total voltage of the battery through the impedance module, and calculating the impedance of each sub-tab corresponding region.

[0025] In the above embodiment, the alternating voltage or alternating current disturbance is applied to the battery by the impedance module to simulate the alternating disturbance signal received by the battery during operation, and the polarization current of each sub-tab corresponding region and the amplitude and phase of the total voltage of the battery are obtained by the impedance module, so as to calculate the impedance of each sub-tab corresponding region according to the polarization current of each sub-tab corresponding region and the amplitude and phase of the total voltage of the battery, and further obtain the AC impedance spectrum of each local region in the battery, so as to analyze the difference behaviors of different regions in terms of electrochemical reaction kinetics and interface stability, and obtain the battery polarization distribution characteristics.

[0026] Some embodiments of the present application also provide a battery polarization distribution characteristic detection device for implementing the above-mentioned battery polarization distribution characteristic detection method, which comprises: a charge and discharge device comprising a first electrode and a second electrode; and a battery comprising a first tab and a second tab, the first tab being divided into N sub-tabs, the N sub-tabs being connected in parallel and connected in parallel to the first electrode, and the second tab being connected to the second electrode.

[0027] In the above embodiment, the complete first tab is divided into a plurality of mutually electrically isolated sub-tabs, and the polarization current of each sub-tab corresponding region is independently measured. Compared with the unified measurement of the whole tab, the uniformization effect of the connected current collector in the battery on the electrode current distribution can be reduced, the local polarization difference of different regions on the tab surface can be more truly reflected, and the quantitative detection of the local polarization current of different regions on the tab surface can obtain the difference information of the electrochemical reaction rate, electrolyte distribution, and material activity of each region on the tab surface, providing data support for analyzing the battery polarization distribution characteristics.

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

[0029] In the above embodiments, by configuring an independent first tab for each sub-tab, the current in the corresponding area of each sub-tab can be separately led out, reducing the current distribution uniformization effect of the connected current collector, thereby realizing accurate detection of local electrochemical reaction; in the parallel connection mode, each sub-tab is connected to the circuit through an independent first tab, which helps to reduce the influence of local resistance difference and the influence of overall current distribution uniformity, and by obtaining the current distribution information of different areas inside the battery, it is helpful to analyze the battery polarization distribution characteristics and other phenomena.

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

[0031] In the above embodiments, by sequentially laying and stacking N sub-tabs along the length direction of the second tab on the second tab, and setting a separator between each sub-tab and the second tab to achieve electrical insulation and isolation, a kind of stacked electrode assembly structure is formed, which can increase the arrangement area of active material in the limited battery shell space, thereby improving the energy density per unit volume and per unit mass.

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

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

[0034] In some embodiments, the auxiliary tool comprises N pressure plates, and the N pressure plates are respectively and one-to-one corresponding to the N sub-tabs.

[0035] In the above embodiments, by separately configuring one pressure plate in the auxiliary tool for each sub-tab, and using the pressure plate to apply an independently controllable pressure to the corresponding sub-tab and the second tab, the local stress of the battery can be adjusted, thereby accurately simulating the contact pressure distribution between the tabs in different areas inside the battery, with high parameter control freedom, which can be used to simulate the uneven contact pressure between the planar electrodes caused by structural differences or assembly process in different positions inside the battery, improving the accuracy and adaptability of the simulation experiment.

[0036] In some embodiments, the auxiliary tool comprises: a base configured to carry the battery; and a pressing plate movably provided 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 pole pieces under different assembly conditions in actual use of the battery can be effectively simulated, providing an experimental basis for studying the pole piece interface behavior and contact impedance changes. The auxiliary tool can reproduce the stress state in 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 is movable relative to the base, facilitating stable pressing of the battery and thus improving the accuracy and repeatability of the test results. By changing the displacement or loading force of the pressing plate, 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 auxiliary tool has a compact, simple and convenient-to-operate overall structure.

[0038] In some embodiments, the auxiliary tool further comprises: a top plate, a guide column connecting the top plate and the base, the pressing plate being provided between the top plate and the base and penetrating the guide column; and a thrust member provided on the top plate and connected to the pressing plate through the top plate.

[0039] In the above embodiments, by providing the guide column, a stable movement guide path is provided for the pressing plate, so that the parallelism and perpendicularity of the pressing plate are maintained during lifting, the top plate and the base are firmly connected through the guide column to form a stable frame structure, and the overall mechanical strength and service life of the auxiliary tool are improved; the thrust member is directly connected to the pressing plate and can be driven by manual, electric, pneumatic or hydraulic means, and combined with a control system to realize precise adjustment and dynamic control of the applied pressure, meet the needs of contact pressure simulation under different experimental conditions, and improve the intelligent level and operation convenience of the equipment.

[0040] In some embodiments, the battery polarization distribution characteristic detection device further comprises: N first electrode wires respectively connected one-to-one with the N sub-pole pieces; and N current detection elements respectively provided one-to-one on the N first electrode wires.

[0041] In the above embodiments, by configuring the first electrode line 50 and the current detection element independently for each sub-pole piece, the current distribution of different sub-pole piece corresponding regions in the battery can be monitored in real time and independently, so as to obtain more detailed electrochemical behavior data. In addition, according to the polarization current information of each sub-pole piece corresponding region obtained by the current detection element, the local polarization phenomenon caused by factors such as contact pressure difference, uneven distribution of electrolyte or interface side reaction can be analyzed, which can provide a basis for optimizing the electrode structure design, and can more accurately judge the aging trend, capacity attenuation mechanism and failure position of the battery in the cycle process.

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

[0043] In the above embodiments, the data of the current detection element is collected and processed by the control module, which improves the real-time and accuracy of data collection. In addition, based on the received polarization current signals, the control module can analyze the reaction activity, interface impedance change and local polarization degree of each region of the battery, which is helpful to study the complex electrochemical behavior such as uneven current distribution and pressure difference in the battery.

[0044] In some embodiments, the charge and discharge equipment further comprises an impedance module configured to apply an alternating voltage or alternating current disturbance to the battery, and configured to calculate the impedance of each sub-pole piece corresponding region according to the polarization current of each sub-pole piece corresponding region and the amplitude and phase of the total voltage of the battery.

[0045] In the above embodiments, the impedance module applies an alternating voltage disturbance or an alternating current disturbance to the battery to simulate the alternating disturbance signal received by the battery during operation. In addition, the impedance module obtains the polarization current of each sub-pole piece corresponding region and the amplitude and phase of the total voltage of the battery. The impedance module further calculates the impedance of each sub-pole piece corresponding region according to the polarization current of each sub-pole piece corresponding region and the amplitude and phase of the total voltage of the battery, and obtains the AC impedance spectrum of each local region in the battery, so as to analyze the difference in electrochemical reaction kinetics and interface stability of different regions, and obtain the polarization distribution characteristics of the battery.

[0046] Based on the above technical solutions, the present application has at least the following beneficial effects:

[0047] In some embodiments, the complete first pole piece is divided into a plurality of mutually electrically isolated sub-pole pieces, and the polarization current of the corresponding region of each sub-pole piece is independently measured. Compared with the unified measurement of the whole pole piece, the uniformization effect of the connected current collector on the electrode current distribution in the battery can be reduced, the local polarization difference of the different regions on the pole piece surface can be more truly reflected, and the quantitative detection of the local polarization current of the different regions on the pole piece surface can obtain the difference information of the different regions on the pole piece surface in terms of electrochemical reaction rate, electrolyte distribution, material activity, etc., thereby providing data support for analyzing the polarization distribution characteristics of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments of the present application will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by the drawings without creative labor.

[0049] Figure 1 is a structural schematic diagram of a vehicle disclosed by some embodiments of the present application;

[0050] Figure 2 is an exploded structural schematic diagram of a battery device disclosed by some embodiments of the present application;

[0051] Figure 3 is an exploded structural schematic diagram of a battery disclosed by some embodiments of the present application;

[0052] Figure 4 is a structural schematic diagram of the first pole piece divided into a plurality of sub-pole pieces and the second pole piece stacked disclosed by some embodiments of the present application;

[0053] Figure 5 is a schematic diagram of a battery polarization distribution characteristic detection device disclosed by some embodiments of the present application.

[0054] In the drawings, the drawings are not drawn according to the actual proportion.

[0055] Label description: 1-first pole piece; 11-sub pole piece; 12-first pole lug; 2-second pole piece; 21-second pole lug; 3-separator; 10-battery; 20-aid tool; 201-base; 202-pressing plate; 203-top plate; 204-guide column; 205-thrust piece; 207-pressure detection element; 30-charging and discharging equipment; 31-first electrode; 32-second electrode; 40-current detection element; 50-first electrode line; 60-bus line; 70-second electrode line; 100-battery device; 101-box body; 101a-first box body; 101b-second box body; 10a-housing; 10b-end cover; 10c-electrode assembly; 10d-pole column; 10e-explosion-proof valve; 200-vehicle; 210-axle; 220-wheel; 230-motor; 240-controller. DETAILED DESCRIPTION

[0056] The embodiments of the present application will be further described below in conjunction with the drawings and examples. The detailed description and drawings of the following examples are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0057] In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is more than two; the orientation or position relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer" and the like only serves to facilitate the description of the present application and simplify the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable range of error. "Parallel" is not strictly parallel, but within the allowable range of error.

[0058] The orientation words appearing in the following description are the directions shown in the drawings, and are not a limitation on the specific structure of the present application. In the description of the present application, it should also be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connection" should be interpreted broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0059] With the development of market situation, the application of battery device is increasingly wide. At present, the battery device is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely applied to electric motorcycles, electric vehicles and other electric vehicles, and other fields. As can be seen, the battery device can not only be used as a power supply for an electric device, but also be used as an energy storage element for various energy storage systems.

[0060] Reference Figure 1 In some embodiments, the battery device is used as a power supply for an electric device, and the electric device is a vehicle 200. The vehicle 200 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric vehicle, a hybrid electric vehicle or a range extended vehicle.

[0061] The vehicle 200 is internally provided with the 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 be used as an operating power supply of the vehicle 200. The vehicle 200 can also include an axle 210, a wheel 220 connected to the axle 210, 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 motor 230 to work. The battery device 100 can be used to provide electric energy for the work of the motor 230 and other components in the vehicle.

[0062] Therefore, the battery device 100 can not only be used as an operating power supply of the vehicle 200, but also be used as a driving power supply of the vehicle 200, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle 200.

[0063] Reference Figure 2 In some embodiments, the battery device 100 includes a box body 101 and a battery 10, and the battery 10 is contained 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 are overlapped with each other, and the first box body 101a and the second box body 101b jointly define a containing space for containing the battery 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-shaped structure, which is overlapped with 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 containing space. The first box body 101a and the second box body 101b can also be hollow structures with one side open, and the open side of the first box body 101a is overlapped with 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 have various shapes, such as a cylinder or a cuboid.

[0064] The battery 10 can be multiple, and the multiple batteries 10 can be connected in series or in parallel or in a mixed connection. The mixed connection means that the multiple batteries 10 are connected in series and in parallel. The multiple batteries 10 can be connected in series or in parallel or in a mixed connection, and the whole of the multiple batteries 10 is accommodated in the case 101. Of course, the battery device 100 can also be that the multiple batteries 10 are connected in series or in parallel or in a mixed connection to form a battery module, and the multiple battery modules are connected in series or in parallel or in a mixed connection to form a whole, and are accommodated in the case 101. The battery device 100 can also include other components, for example, the battery device 100 can also include a busbar assembly for realizing the electrical connection between the multiple batteries 10.

[0065] 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.

[0066] Reference Figure 3 In some embodiments, the battery 10 includes a shell 10a, an end cover 10b, and an electrode assembly 10c. The shell 10a is determined according to the shape of the combined one or more electrode assemblies 10c, for example, the shell 10a can be a hollow cuboid or a square or a cylinder, and one of the faces of the shell 10a has an opening so as to place the one or more electrode assemblies 10c in the shell 10a. For example, when the shell 10a is a hollow cuboid or a square, one of the flat faces of the shell 10a is an open face, i.e., the flat face does not have a shell wall so that the inside and outside of the shell 10a are communicated; when the shell 10a is a hollow cylinder, the circular side face of the shell 10a is an open face, i.e., the circular side face does not have a shell wall so that the inside and outside of the shell 10a are communicated. The end cover 10b is connected to the shell 10a at the opening of the shell 10a to form a closed shell for placing the electrode assembly 10c.

[0067] The end cover 10b is basically a flat plate, and two pole posts 10d are provided on the end cover 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 cover 10b. When the gas generated by the battery 10 is too much, the gas expands to increase the gas pressure in the shell 10a to exceed a preset value, the explosion-proof valve 10e can be cracked to cause the inside and outside of the shell 10a to be communicated, and the gas is released outward through the cracked explosion-proof valve 10e, thereby avoiding explosion.

[0068] In some embodiments, the electrode assembly 10c mainly includes two structural forms of winding type and stacking type. Among them, the winding type structure is to cut the positive electrode sheet, the negative electrode sheet and the separator into a strip, and then stack and wind them into a compact core. The stacking type structure is to stack the positive electrode sheet, the negative electrode sheet and the separator one by one. Whether it is a winding type structure or a stacking type structure, the positive electrode sheet and the negative electrode sheet are separated by the separator to prevent direct contact between the positive electrode sheet and the negative electrode sheet and to avoid short circuit.

[0069] As the size of the electrode assembly 10c of the commercial lithium ion battery gradually increases, the problem of uneven distribution of internal physical field is 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 rate at different positions will be different. This difference in 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, thereby affecting the overall output performance and service life of the battery.

[0070] Therefore, the detection and analysis of the polarization distribution characteristics of the battery are crucial for the optimal design of the structure and materials of the battery. In some related technologies, the test method adopted can only represent 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 sheet area, local polarization phenomena and their causes can be more accurately identified, which can be used to improve battery design and improve battery performance and prolong service life.

[0071] Based on this, with reference to Figure 4 and Figure 5 some embodiments of the present application provide a battery polarization distribution characteristic detection method and device, which can more accurately detect the current distribution on the surface of the electrode sheet and realize quantitative detection of the local polarization current in different regions of the electrode surface, so as to more accurately analyze the polarization distribution characteristics of the battery.

[0072] In some embodiments, the battery polarization distribution characteristic detection method includes the following steps,

[0073] S10: dividing the first electrode sheet 1 of the battery 10 into N sub-electrode sheets 11; wherein N is greater than or equal to 2, with reference to Figure 4 ;

[0074] S20: connecting the N sub-electrode sheets 11 in parallel and then connecting them in parallel to the first electrode 31 of the charge and discharge device 30, and connecting the second electrode sheet 2 of the battery 10 to the second electrode 32 of the charge and discharge device 30, with reference to Figure 5 ; and

[0075] S30: Obtain the polarization current of each sub-pole piece 11 corresponding to the area of each sub-pole piece 11 of the N sub-pole pieces 11 for analyzing the battery polarization distribution characteristics.

[0076] In the above embodiment, the inside of the battery 10 is to divide the first pole piece 1 into N sub-pole pieces 11, and the N sub-pole pieces 11 are isolated from the second pole piece 2 of the battery 10 by the separator 3.

[0077] In the above embodiment, the outside of the battery 10 is to connect the N sub-pole pieces 11 in parallel first, and then connect them in parallel to the first electrode 31 of the charging and discharging device 30, and the second pole piece 2 is connected to the second electrode 32 of the charging and discharging device 30. The polarity of the first electrode 31 is consistent with the polarity of the first pole piece 1, and the polarity of the second electrode 32 is consistent with the polarity of the second pole piece 2.

[0078] In some embodiments, the first pole piece 1 is a positive pole piece, and the second pole piece 2 is a negative pole piece. Alternatively, the first pole piece 1 is a negative pole piece, and the second pole piece 2 is a positive pole piece.

[0079] In the above embodiment, by arranging the separator 3 between the first pole piece 1 and the second pole piece 2 of different polarities, the electrical insulation performance between the first pole piece 1 and the second pole piece 2 can be realized, the internal short circuit caused by direct contact can be avoided, and the safety and reliability of the battery can be improved.

[0080] In the above embodiment, the charging and discharging device 30 is configured to perform charging or discharging operation on the battery 10 to simulate the working state of the battery 10 in actual application. During charging, the charging and discharging device 30 inputs the energy of external power source (such as power grid or direct current power source) to the battery 10 in the form of set current or voltage, so that the battery 10 stores electrical energy. During discharging, the charging and discharging device 30 absorbs the energy released by the battery, and can be used for load.

[0081] In the above embodiment, the complete first pole piece 1 is divided into a plurality of mutually electrically isolated sub-pole pieces 11, and the polarization current of each sub-pole piece 11 corresponding area is measured independently. Compared with the unified measurement of the whole pole piece, the homogenization effect of the connected current collector in the battery on the electrode current distribution can be reduced, the local polarization difference of different areas on the surface of the pole piece can be more truly reflected, and the quantitative detection of the local polarization current of different areas on the surface of the pole piece can obtain the difference information of the electrochemical reaction rate, electrolyte distribution, material activity, etc. of each area on the surface of the pole piece, providing data support for analyzing the battery polarization distribution characteristics; and based on the polarization characteristics of each sub-pole piece 11, the performance weak area can be identified to guide the improvement of electrode structure, material distribution and manufacturing process, and improve the consistency and cycle life of the whole battery 10.

[0082] In the above embodiment, N is greater than or equal to 2, and optionally, N is equal to 3, 4 or 5, etc.

[0083] In some embodiments, step S10 further comprises: sequentially and spacedly making N first tabs 12 along the length direction of the first tab 1, and each of the divided sub-tab 11 has one first tab 12.

[0084] In the above embodiments, by configuring each sub-tab 11 with an independent first tab 12, the current in the corresponding area of each sub-tab 11 can be separately led out, reducing the current distribution equalization effect of the connected current collector, thereby realizing accurate detection of local electrochemical reaction; in the parallel connection mode, each sub-tab 11 is connected to the circuit through an independent first tab 12, which helps to reduce the impact of local resistance difference and the impact of overall current distribution uniformity, and through the obtained current distribution information of different areas inside the battery, it is helpful to analyze the battery polarization distribution characteristics and other phenomena, to provide data support for battery health state evaluation, dynamic balancing control and intelligent management strategy, and to improve the safety and service life of the battery system.

[0085] In some embodiments, in step S10, N sub-tabs 11 are sequentially laid on the second tab 2 along the length direction of the second tab 2.

[0086] In the above embodiments, by sequentially laying and stacking N sub-tabs 11 on the second tab 2 along the length direction of the second tab 2, and setting a separator 3 between the N sub-tabs 11 and the second tab 2 to achieve electrical insulation, a laminated electrode assembly structure is formed, which can increase the arrangement area of active materials in a limited battery shell space, thereby improving the energy density per unit volume and per unit mass.

[0087] In some embodiments, step S10 further comprises: having a gap between the adjacent two sub-tabs 11.

[0088] In the above embodiments, the complete first tab 1 is divided into multiple sub-tabs 11, which is conducive to independent measurement of the polarization current in the corresponding area of each sub-tab 11, and the gap between the adjacent two sub-tabs 11 can form electrical isolation between the adjacent two sub-tabs 11, reducing the risk of internal short circuit caused by contact between the adjacent two sub-tabs 11 due to external impact, vibration or thermal expansion, etc.

[0089] In some embodiments, step S10 further comprises: completely accommodating the N sub-tabs 11 within the geometric range of the second tab 2.

[0090] In the above embodiment, the sum of the sizes of the N sub-poles 11 in the length direction of the second pole 2 is less than the length of the second pole 2; the width of the sub-pole 11 is less than the width of the second pole 2; and the total area of the N sub-poles 11 is less than the total area of the second pole 2. The N sub-poles 11 do not exceed the contour boundary of the second pole 2 in the length direction of the second pole 2; and the sub-pole 11 does not exceed the contour boundary of the second pole 2 in the width direction of the second pole 2.

[0091] In the above embodiment, the first pole 1 and the second pole 2 are both long strip-shaped poles, the length of the first pole 1 is less than the length of the second pole 2, and the width of the first pole 1 is less than the width of the second pole 2. The first pole 1 is sequentially divided into N sub-poles 11 along the length direction, and the N sub-poles 11 are laid on the second pole 2 along the length direction of the second pole 2, and one sub-pole 11 is laid in the width direction of the second pole 2.

[0092] In the above embodiment, the N sub-poles 11 are completely accommodated in the geometric range of the second pole 2, which can help to accurately control the effective reaction area between different polarity poles and reduce the occurrence of local overcharge or overdischarge.

[0093] In some embodiments, between step S20 and step S30, there is also step S21: using the auxiliary tool 20 to apply a controllable pressure to the battery 10 to simulate the contact pressure between the first pole 1 and the second pole 2.

[0094] In the above embodiment, the auxiliary tool 20 is used to apply pressure to the battery 10, so that each layer of the battery 10, such as the first pole 1 and the second pole 2, is in a state of being under pressure, thereby simulating the contact pressure environment between the poles inside the battery 10; and the auxiliary tool 20 has an adjustable pressure applying function, which can adjust the applied pressure value according to different test requirements, so as to simulate different contact pressure distribution situations caused by differences in assembly process, stacking structure or packaging method of the actual battery, thereby more comprehensively analyzing the battery polarization distribution characteristics caused by different reasons.

[0095] In some embodiments, step S21 further comprises: configuring a pressure plate 202 of the auxiliary tool 20 for each sub-pole 11 of the N sub-poles 11, and applying pressure to the corresponding sub-pole 11 and the second pole 2 through the pressure plate 202.

[0096] In the above embodiment, by separately configuring one pressing plate 202 in the auxiliary tool 20 for each sub-pole piece 11, and using the pressing plate 202 to apply an independently controllable pressure on the corresponding sub-pole piece 11 and the second pole piece 2, the local stress of the battery 10 can be adjusted, so that the contact pressure distribution between the pole pieces in different regions inside the battery 10 can be more accurately simulated, the degree of freedom of parameter control is higher, and the simulation experiment can be used to simulate the uneven contact pressure between the planar electrodes caused by structural differences or assembly process at different positions inside the battery, and the accuracy and adaptability of the simulation experiment are improved.

[0097] In some embodiments, step S21 further includes that the pressing plate 202 is provided with a pressure detection element 207, and the pressure applied by the pressing plate 202 on the corresponding sub-pole piece 11 and the second pole piece 2 is detected through the pressure detection element 207.

[0098] In the above embodiment, the pressure detection element 207 is pre-installed in the pressing plate 202, the pressure applied by the pressing plate 202 on the corresponding sub-pole piece 11 and the second pole piece 2 is detected through the pressure detection element 207, the contact pressure between each sub-pole piece 11 and the second pole piece 2 can be monitored in real time, and the force of the pressing plate 202 can be adjusted according to the pressure feedback by the pressure detection element 207, so as to realize accurate control and feedback adjustment of the pressure, so that the pressure applied by each sub-pole piece 11 to the corresponding region meets the preset requirements, the controllability and repeatability of the experiment or test process are improved, and the accuracy of simulating the internal pressure environment of the real battery is improved; and by applying different pressure values to different sub-pole pieces 11, the influence of pressure change on the electrochemical performance such as interface impedance, lithium ion transmission rate and polarization behavior can be systematically studied, and a theoretical basis for optimizing battery design and assembly process is provided.

[0099] In some embodiments, the pressure detection element 207 includes a pressure sensor or the like.

[0100] In some embodiments, step S20 further includes that the N first electrode lines 50 are respectively connected to the N sub-pole pieces 11 in one-to-one correspondence, and each first electrode line 50 is provided with a current detection element 40, and the polarization current of the corresponding region of the sub-pole piece 11 in the charging and discharging process of the battery 10 is detected through the current detection element 40.

[0101] In the above embodiments, by configuring the independent first electrode line 50 and the current detection element 40 for each sub-pole piece 11, the current distribution of different sub-pole piece 11 corresponding regions in the battery can be monitored in real time and independently, so as to obtain more detailed electrochemical behavior data. According to the polarization current information of each sub-pole piece 11 corresponding region obtained by the current detection element 40, the local polarization phenomenon caused by factors such as contact pressure difference, uneven distribution of electrolyte or interface side reaction can be analyzed, which can provide basis for optimizing the electrode structure design, and can more accurately judge the aging trend, capacity attenuation mechanism and failure position of the battery in the cycle process.

[0102] In the above embodiments, by integrating the current detection element 40 in the plurality of parallelly connected first electrode lines 50 arranged outside the battery 10, quantitative monitoring of the current distribution of different sub-pole piece 11 corresponding regions can be realized; and without implanting any sensing components inside the battery 10, the influence on the intrinsic characteristics of the battery caused by the introduction of sensors inside the battery can be avoided.

[0103] In some embodiments, the current detection element 40 includes a current sensor or the like.

[0104] In some embodiments, the step S30 further includes: a control module is arranged in the charge and discharge equipment 30, the control module is electrically connected with the current detection element 40, and the polarization current signal sent by the current detection element 40 is acquired through the control module.

[0105] In the above embodiments, the data of the current detection element 40 is collected and processed through the control module, which improves the real-time performance and accuracy of data collection; and the control module can analyze the received polarization current signal to obtain the reaction activity, interface impedance change and local polarization degree of each region of the battery, and other polarization distribution characteristics of the battery, which is helpful to study the complex electrochemical behavior such as uneven current distribution and pressure difference in the battery.

[0106] In some embodiments, the step S30 further includes: an impedance module is arranged in the charge and discharge equipment 30, an alternating voltage disturbance or an alternating current disturbance is applied to the battery 10 through the impedance module, the polarization current of each sub-pole piece 11 corresponding region and the amplitude and phase of the total voltage of the battery 10 are acquired through the impedance module, and the impedance of each sub-pole piece 11 corresponding region is calculated.

[0107] In the above embodiment, the alternating voltage or alternating current perturbation is applied to the battery 10 by the impedance module to simulate the alternating perturbation signal received by the battery 10 during operation, and the polarization current of each sub-pole piece 11 corresponding region and the amplitude and phase of the total voltage of the battery 10 are obtained by the impedance module, so as to calculate the impedance of each sub-pole piece 11 corresponding region according to the polarization current of each sub-pole piece 11 corresponding region and the amplitude and phase of the total voltage of the battery 10, and then obtain the alternating current impedance spectrum of each local region in the battery, so as to analyze the difference behavior of different regions in the aspects of electrochemical reaction kinetics, interface stability and the like, and obtain the battery polarization distribution characteristics.

[0108] Compared with the evaluation method relying only on the overall battery voltage and current, the embodiment of the application can obtain more fine regional impedance data, which is helpful to improve the evaluation accuracy of the key parameters such as the battery health state and the capacity attenuation degree.

[0109] Reference Figure 4 and Figure 5 Some embodiments of the application also provide a battery polarization distribution characteristic detection device for implementing the above-mentioned battery polarization distribution characteristic detection method.

[0110] In some embodiments, the battery polarization distribution characteristic detection device comprises:

[0111] The charge and discharge device 30 comprises a first electrode 31 and a second electrode 32; and

[0112] The battery 10 comprises a first pole piece 1 and a second pole piece 2, the first pole piece 1 is divided into N sub-pole pieces 11, the N sub-pole pieces 11 are connected in parallel and are connected in parallel to the first electrode 31, and the second pole piece 2 is connected to the second electrode 32.

[0113] In the above embodiment, the charge and discharge device 30 is configured to perform charging or discharging operation on the battery 10 to simulate the working state of the battery 10 in actual application. During charging, the charge and discharge device 30 inputs the energy (such as power grid or direct current power supply) of external power supply to the battery 10 in the form of set current or voltage, so that the battery 10 stores electric energy. During discharging, the charge and discharge device 30 absorbs the energy released by the battery 10, and can be used on the load.

[0114] In the above embodiment, the complete first electrode sheet 1 is divided into a plurality of mutually electrically isolated sub-electrode sheets 11, which can independently measure the polarization current of the corresponding area of each sub-electrode sheet 11. Compared with the uniform measurement of the entire electrode sheet, the homogenization effect of the connected current collector on the electrode current distribution can be reduced, the local polarization differences of different areas on the electrode sheet surface can be more truly reflected, and the quantitative detection of the local polarization current of different areas on the electrode sheet surface can obtain the difference information of the electrochemical reaction rate, electrolyte distribution, material activity, etc. of each area on the electrode sheet surface, providing data support for analyzing the polarization distribution characteristics of the battery, etc. Based on the polarization characteristics of each sub-electrode sheet 11, the performance weak area 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.

[0115] In some embodiments, the first tab 12 is arranged on each of the N sub-electrode sheets 11.

[0116] In the above embodiment, by configuring an independent first tab 12 for each sub-electrode sheet 11, the current of the corresponding area of each sub-electrode sheet 11 can be respectively led out, reducing the current distribution homogenization effect of the connected current collector, thereby realizing accurate detection of local electrochemical reaction. In the parallel connection mode, each sub-electrode sheet 11 is connected to the circuit through an independent first tab 12, which helps to reduce the influence of local resistance difference and the influence of overall current distribution uniformity, and can obtain the current distribution information of different areas inside the battery, which helps to analyze polarization unevenness, material aging, etc. and provides data support for battery health state evaluation, dynamic balancing control and intelligent management strategy, improving the safety and service life of the battery system.

[0117] In some embodiments, the battery 10 further comprises a separator 3 arranged between the first electrode sheet 1 and the second electrode sheet 2, and the N sub-electrode sheets 11 are arranged in sequence along the length direction of the second electrode sheet 2.

[0118] In the above embodiment, the N sub-electrode sheets 11 are sequentially laid and stacked on the second electrode sheet 2 along the length direction of the second electrode sheet 2, and a separator 3 is arranged between each sub-electrode sheet 11 and the second electrode sheet 2 to achieve electrical insulation and isolation, thereby forming a kind of electrode assembly structure similar to the laminated sheet. This structure can increase the arrangement area of active materials in the limited battery shell space, thereby improving the energy density per unit volume and per unit mass.

[0119] In the above embodiment, the complete first pole piece 1 is divided into multiple sub-pole pieces 11, which is conducive to independent measurement of the polarization current of the corresponding area of each sub-pole piece 11, and the gap between the adjacent two sub-pole pieces 11 can form electrical isolation between the adjacent two sub-pole pieces 11, reducing the risk of internal short circuit caused by contact between adjacent two sub-pole pieces 11 due to external impact, vibration or thermal expansion, etc.

[0120] In some embodiments, the N sub-pole pieces 11 are completely accommodated within the geometric range of the second pole piece 2.

[0121] In the above embodiment, the N sub-pole pieces 11 are completely accommodated within the geometric range of the second pole piece 2, which can help to accurately control the effective reaction area between different polarity pole pieces and reduce the occurrence of local overcharge or overdischarge.

[0122] In some embodiments, the second pole piece 2 and the separator 3 are not divided, and the second pole piece 2 and the separator 3 are integrated structures.

[0123] In some embodiments, the battery polarization distribution characteristic detection device further comprises an auxiliary tool 20 configured to apply a controllable pressure to the battery 10 to press the N sub-pole pieces 11 and the second pole piece 2.

[0124] In the above embodiment, the auxiliary tool 20 is used to apply pressure to the battery 10, so that each layer of the battery 10 is in a state of being pressed, thereby simulating the contact pressure environment between the internal pole pieces of the battery 10; and the auxiliary tool 20 has an adjustable pressure applying function, which can adjust the pressure value applied according to different test requirements, so as to simulate different contact pressure distribution conditions caused by differences in assembly process, stacking structure or packaging method of the actual battery, thereby more comprehensively analyzing the battery polarization distribution characteristics caused by different reasons.

[0125] The auxiliary tool 20 comprises N pressure plates 202, and the N pressure plates 202 are respectively and correspondingly arranged with the N sub-pole pieces 11.

[0126] In the above embodiment, by configuring one pressure plate 202 in the auxiliary tool 20 for each sub-pole piece 11, and using the pressure plate 202 to apply an independently controllable pressure to the corresponding sub-pole piece 11 and the second pole piece 2, the local stress of the battery 10 can be adjusted, thereby accurately simulating the contact pressure distribution between the pole pieces in different regions inside the battery 10, with high parameter control freedom, which can be used to simulate the uneven contact pressure between the planar electrodes caused by structural differences or assembly process at different positions inside the battery, and improve the accuracy and adaptability of the simulation experiment.

[0127] In some embodiments, the auxiliary tool 20 comprises:

[0128] a base 201 configured to carry the battery 10; and

[0129] a pressing plate 202 movably provided on the base 201, the pressing plate 202 being configured to move towards the base 201 to apply a controllable pressure to the battery 10.

[0130] In the above embodiment, by adjusting the pressure applied by the pressing plate 202 to the battery 10, the contact state between the electrode tabs of the battery under different assembly conditions in actual use can be effectively simulated, providing an experimental basis for studying the electrode tab interface behavior and contact impedance changes. The auxiliary tool 20 can reproduce the stress state in the battery packaging or module assembly process in a laboratory environment, making the measured electrochemical performance data more close to the real application scenario and improving the engineering reference value of the experimental results. The pressing plate 202 is movable relative to the base 201, facilitating stable pressure application to the battery 10 and thus improving the accuracy and repeatability of the test results. By changing the displacement or loading force of the pressing plate 202, performance evaluation of the battery 10 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 auxiliary tool 20 has a compact, simple and convenient-to-operate overall structure.

[0131] In some embodiments, the auxiliary tool 20 further comprises:

[0132] a top plate 203,

[0133] a guide column 204 connecting the top plate 203 and the base 201, the pressing plate 202 being provided between the top plate 203 and the base 201 and passing through the guide column 204; and

[0134] a thrust member 205 provided on the top plate 203 and connected to the pressing plate 202 through the top plate 203.

[0135] In the above embodiment, a plurality of guide columns 204 are provided between the top plate 203 and the base 201, the top plate 203 and the base 201 are connected through the guide columns 204, the pressing plate 202 is provided between the top plate 203 and the base 201 and can slide along the guide columns 204, and the thrust member 205 is provided on the top plate 203 and connected to the pressing plate 202 through the top plate 203, for driving the pressing plate 202 to move towards the base 201 to apply pressure to the battery 10.

[0136] In the above embodiment, the guide column 204 is arranged to provide a stable movement guide path for the pressing plate 202, so that the pressing plate 202 can maintain parallelism and perpendicularity during lifting, thereby avoiding uneven pressure distribution caused by deviation or inclination, and improving the repeatability and reliability of test data. The top plate 203 and the base 201 are firmly connected through the guide column 204 to form a stable frame structure, which can effectively withstand the load applied by the thrust member 205, prevent the test results from being affected by structural deformation, and 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, it can realize precise adjustment and dynamic control of the applied pressure, meet the needs of contact pressure simulation under different experimental conditions, and improve the intelligent level and operation convenience of the equipment.

[0137] In some embodiments, the pressing plate 202 is a square plate, and a guide column 204 is arranged at each corner of the pressing plate 202. The pressing plate 202 moves towards or away from the base 201 under the guidance of the four guide columns 204.

[0138] In some embodiments, a pressure detection element 207 is arranged on the pressing plate 202. The pressure detection element 207 is used to detect the force applied by the pressing plate 202 to the battery 10, so as to adjust the force applied by the pressing plate 202 to the battery 10 according to the detection requirements, improve the accuracy of the simulation of the contact state of the electrode sheet, and be suitable for studying the influence of different pressures on the electrochemical performance of the battery.

[0139] In some embodiments, the battery polarization distribution characteristic detection device further comprises:

[0140] N first electrode lines 50, each corresponding to one of the N sub-electrode sheets 11; and

[0141] N current detection elements 40, each corresponding to one of the N first electrode lines 50.

[0142] In the above embodiment, by configuring an independent first electrode line 50 and a current detection element 40 for each sub-electrode sheet 11, the current distribution of the corresponding area of each sub-electrode sheet 11 in the battery can be monitored in real time and independently, so as to obtain more detailed electrochemical behavior data. Based on the polarization current information of the corresponding area of each sub-electrode sheet 11 obtained by the current detection element 40, the local polarization phenomenon caused by factors such as contact pressure difference, uneven distribution of electrolyte or interface side reaction can be analyzed, which can provide a basis for optimizing the electrode structure design, and can more accurately judge the aging trend, capacity attenuation mechanism and failure position of the battery during the cycle process.

[0143] In the above embodiments, by integrating the current detection elements 40 in the plurality of first electrode lines 50 arranged outside the battery 10, quantitative monitoring of the current distribution in different regions corresponding to the sub-poles 11 can be achieved, without the need to implant any sensing components inside the battery 10, and without causing any influence on the intrinsic characteristics of the battery due to the introduction of internal sensors.

[0144] In the above embodiments, the first electrode lines 50 are connected to the first tabs 12 of the sub-poles 11.

[0145] In some embodiments, the battery polarization distribution characteristic detection device further comprises a bus bar 60, the N first electrode lines 50 are connected to a first end of the bus bar 60, and a second end of the bus bar 60 is connected to the first electrode 31 of the charge-discharge device 30.

[0146] In some embodiments, the battery polarization distribution characteristic detection device further comprises a second electrode line 70, the second electrode line 70 is connected to the second pole 2 and the second electrode 32 of the charge-discharge device 30. Specifically, the second electrode line 70 is connected to the second tab 21 of the second pole 2 and the second electrode 32 of the charge-discharge device 30.

[0147] In some embodiments, the charge-discharge device 30 comprises a control module, which is electrically connected to the N current detection elements 40 to obtain the polarization current signals sent by the N current detection elements 40.

[0148] In the above embodiments, by collecting and processing the data of the current detection elements 40 through the control module, the real-time performance and accuracy of data collection are improved; and based on the received polarization current signals, the control module can analyze the reaction activity, interface impedance change, and local polarization degree of each region of the battery, and other battery polarization distribution characteristics, which is helpful for studying the complex electrochemical behaviors such as uneven current distribution and pressure difference inside the battery.

[0149] In some embodiments, the charge-discharge device 30 further comprises an impedance module, which is configured to apply an alternating voltage disturbance or an alternating current disturbance to the battery 10, and is further configured to calculate the impedance of each region corresponding to the sub-pole 11 according to the polarization current of each region corresponding to the sub-pole 11 and the amplitude and phase of the total voltage of the battery 10.

[0150] In the above embodiment, the alternating voltage perturbation or the alternating current perturbation is applied to the battery 10 by the impedance module to simulate the alternating perturbation signal received by the battery 10 during operation, and the polarization current of each sub-tab 11 corresponding region and the amplitude and phase of the total voltage of the battery 10 are obtained by the impedance module. The impedance module also calculates the impedance of each sub-tab 11 corresponding region according to the polarization current of each sub-tab 11 corresponding region and the amplitude and phase of the total voltage of the battery 10, and further obtains the alternating current impedance spectrum of each local region inside the battery, so as to analyze the difference in behavior of different regions in terms of electrochemical reaction kinetics, interface stability, etc., and obtain the battery polarization distribution characteristics.

[0151] Compared with the evaluation method relying only on the overall battery voltage and current, the embodiment of the application can obtain more detailed regional impedance data, which helps to improve the evaluation accuracy of key parameters such as battery health state and capacity decay degree.

[0152] In some embodiments, the battery 10 includes a stacked battery. Optionally, the battery 10 includes a stacked lithium battery.

[0153] Some specific embodiments of the battery polarization distribution characteristic detection device are described in detail below with reference to the accompanying drawings. Figure 4 and the accompanying drawings Figure 5 In this specific embodiment, the first tab 1 is a positive tab, and the second tab 2 is a negative tab.

[0154] Before measuring the current distribution characteristics of the stacked battery, in order to avoid the high-conductivity connecting current collector homogenizing the reaction current distribution on the electrode surface, the first tab 1 of the battery 10 is segmented in advance. Specifically, a plurality of first tabs 12 are processed on the long side of the first tab 1, and the first tab 1 is segmented into N sub-tabs 11 along the length direction, wherein each sub-tab 11 corresponds to a current detection partition, each sub-tab 11 contains at least one first tab 12, and the number N of sub-tabs 11 is greater than or equal to 2.

[0155] During the stacking process of the battery 10, each sub-tab 11 is placed in turn along the length direction of the second tab 2, and the sub-tabs 11 are not in contact with each other with a gap therebetween. The first tab 1 and the second tab 2 are separated by the separator 3. Among them, the second tab 2 and the separator 3 are not segmented, and the total length and total area of the first tab 1 are less than the total length and total area of the second tab 2.

[0156] The above-mentioned laminated battery is pressed by using a whole auxiliary tool or a distributed auxiliary tool. The pressing plate area and the base area of the whole auxiliary tool are both greater than the total area of the first electrode sheet 1. The distributed auxiliary tool includes a plurality of parallel movable pressing plates 202, the area of each movable pressing plate 202 is greater than the area of the sub-electrode sheet 11, the inside of the pressing plate 202 is provided with a pressure detection element 207, the stroke of each movable pressing plate 202 can be independently adjusted, and each movable pressing plate 202 covers a sub-electrode sheet 11 when the battery 10 is clamped. The distributed auxiliary tool can be used to simulate the polarization unevenness caused by the uneven contact pressure between the electrodes of the battery 10.

[0157] The battery polarization distribution characteristic detection device further includes a plurality of parallel first electrode lines 50 and at least one second electrode line 70. The second electrode tab 21 led out by the second electrode sheet 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-discharge device 30. Each first electrode tab 12 led out by each sub-electrode sheet 11 is 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-discharge device 30. Each first electrode line 50 is provided with a current detection element 40, which is used to detect the polarization current of the corresponding area of each sub-electrode sheet 11 during the charging and discharging of the battery 10.

[0158] The charge-discharge device 30 is used to charge and discharge the laminated battery 10, and simultaneously obtain the current distribution of the battery 10.

[0159] The charge-discharge device 30 is also used to apply an alternating voltage disturbance or an alternating current disturbance to the battery 10, and can obtain the branch current of each first electrode line 50, the amplitude and phase of the total voltage of the battery 10 in real time. 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 sheet 11. The impedance module of the charge-discharge device 30 can calculate the impedance of each parallel branch according to the obtained voltage data and current data, that is, the partitioned alternating current impedance of the laminated battery 10.

[0160] The segmentation of the electrode sheet of the battery 10 in the embodiment of the application can avoid the uniformization of the electrode current distribution caused by the communication collector inside the battery, thereby effectively extracting the polarization current distribution information of the electrode surface. The battery polarization distribution characteristic detection method and device provided by the embodiment of the application have the beneficial effects of low cost, simple operation, reliable test results, strong scalability and the like.

[0161] Based on the above-mentioned embodiments of the application, the technical features of one embodiment can be beneficially combined with one or more other embodiments without explicit negation or conflict.

[0162] Although the present application has been described with reference to preferred embodiments, various modifications can be made to the application without departing from the scope of the application. In particular, the technical features mentioned in the various embodiments can be combined in any way, provided that there is no structural conflict. 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 of detecting a polarization distribution characteristic of a battery, characterized by, The method comprises the following steps, S10: dividing a first pole piece (1) of a battery (10) into N sub-pole pieces (11), laying the N sub-pole pieces (11) on a second pole piece (2) in sequence along the length direction of the second pole piece (2), and isolating the N sub-pole pieces (11) from the second pole piece (2) by a diaphragm (3); wherein N is greater than or equal to 2; S20: connecting the N sub-pole pieces (11) in parallel, then connecting in parallel to a first electrode (31) of a charging and discharging device (30), and connecting the second pole piece (2) of the battery (10) to a second electrode (32) of the charging and discharging device (30); and S21: applying a controllable pressure to the battery (10) using an auxiliary tool (20), corresponding to each sub-pole piece (11) of the N sub-pole pieces (11), configuring a pressing plate (202) of the auxiliary tool (20), and applying pressure to the corresponding sub-pole piece (11) and the second pole piece (2) through the pressing plate (202) to simulate the contact pressure between the first pole piece (1) and the second pole piece (2); S30: obtaining the polarization current of the corresponding region of each sub-pole piece (11) of the N sub-pole pieces (11) for analyzing the polarization distribution characteristics of the battery.

2. The battery polarization distribution characteristic detection method according to claim 1, characterized by, The step S10 further comprises: spacing N first pole tabs (12) in sequence along the length direction of the first pole piece (1), and making each sub-pole piece (11) after division have one first pole tab (12).

3. The method of claim 1, wherein The step S10 further comprises: having a gap between the adjacent two sub-pole pieces (11).

4. The method of claim 1, wherein The step S10 further comprises: completely accommodating the N sub-pole pieces (11) in the geometric range of the second pole piece (2).

5. The method of claim 1, wherein The step S21 further comprises: 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-pole piece (11) and the second pole piece (2) is detected through the pressure detection element (207).

6. The method of claim 1, wherein The step S20 further comprises: connecting each of the N sub-pole pieces (11) through N first electrode lines (50) one by one, and each first electrode line (50) is provided with a current detection element (40), and the polarization current of the corresponding region of the sub-pole piece (11) in the charging and discharging process of the battery (10) is detected through the current detection element (40).

7. The method of claim 6, wherein The step S30 further comprises: setting a control module in the charging and discharging device (30), the control module is electrically connected with the current detection element (40), and the polarization current signal sent by the current detection element (40) is obtained through the control module.

8. The method of claim 1, wherein The step S30 further comprises: setting an impedance module in the charging and discharging device (30), applying an alternating voltage or alternating current disturbance to the battery (10) through the impedance module, and obtaining the amplitude and phase of the polarization current of the corresponding region of each sub-pole piece (11) and the total voltage of the battery (10) through the impedance module, and calculating the impedance of the corresponding region of each sub-pole piece (11).

9. A battery polarization distribution characteristic detection device characterized by comprising: The detection device comprises: The charging and discharging device (30) comprises a first electrode (31) and a second electrode (32); and The battery (10) comprises 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 parallel to the first electrode (31), and the second electrode plate (2) is connected to the second electrode (32).

10. The battery polarization distribution characteristic detection device according to claim 9, characterized by, A first tab (12) is arranged on each of the N sub-electrode plates (11).

11. The battery polarization distribution characteristic detection device according to claim 9, characterized by The battery (10) further comprises a separator (3) arranged between the first electrode plate (1) and the second electrode plate (2), and the N sub-electrode plates (11) are arranged in sequence along the length direction of the second electrode plate (2).

12. The battery polarization distribution characteristic detection device according to claim 9, characterized by The auxiliary tool (20) is configured to apply a controllable pressure to the battery (10) to press the N sub-electrode plates (11) and the second electrode plate (2) tightly.

13. The battery polarization distribution characteristic detection device according to claim 12, characterized by The auxiliary tool (20) comprises N pressing plates (202), and the N pressing plates (202) are arranged one-to-one corresponding to the N sub-electrode plates (11) respectively.

14. The battery polarization distribution characteristic detection device according to claim 12, characterized by, The auxiliary tool (20) comprises: 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 a controllable pressure to the battery (10).

15. The battery polarization distribution characteristic detection device according to claim 14, characterized by, The auxiliary tool (20) further comprises: A top plate (203), A guide column (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 column (204); and A thrust member (205) arranged on the top plate (203) and connected to the pressing plate (202) through the top plate (203).

16. The battery polarization distribution characteristic detection device according to claim 9, characterized by Further comprising: N first electrode wires (50) connected one-to-one corresponding to the N sub-electrode plates (11) respectively; And N current detection elements (40) arranged one-to-one corresponding to the N first electrode wires (50) respectively.

17. The battery polarization distribution characteristic detection device according to claim 16, characterized by The charging and discharging device (30) comprises a control module electrically connected with the N current detection elements (40) to acquire the polarization current signals sent by the N current detection elements (40).

18. The battery polarization distribution characteristic detection device according to claim 9, characterized by, The charging and discharging device (30) further comprises an impedance module configured to apply an alternating voltage or alternating current disturbance to the battery (10) and configured to calculate the impedance of each sub-electrode plate (11) corresponding area according to the polarization current of each sub-electrode plate (11) corresponding area and the amplitude and phase of the total voltage of the battery (10).

Images