Battery cell and battery pack

Abstract

The application provides a battery monomer and a battery pack. The battery monomer comprises a shell, a cover plate, a connecting piece, and an electrode assembly. The shell comprises an open end and a closed end, and the closed end is internally provided with a signal collection part. The cover plate covers the open end and is combined with the shell to form a containing space. The pole is insulatedly connected to the cover plate. The connecting piece is located in the shell and comprises a first connecting part and a second connecting part. The electrode assembly is arranged in the containing space and comprises at least one main body. The opposite ends of the main body are respectively provided with a collection tab and a power tab. The power tab is electrically connected to the first connecting part, the first connecting part is electrically connected to the pole, the collection tab is electrically connected to the second connecting part, the second connecting part is electrically connected to the signal collection part, and the signal collection part is used for collecting the electrical signal of the electrode assembly and sending the electrical signal to a battery management unit. The charging and discharging path of the battery monomer and the signal collection path are completely physically isolated, and the accuracy of the collected signal is improved.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a battery cell and a battery pack. Background Technology

[0002] With the rapid development of new energy vehicles and the energy storage industry, lithium-ion battery systems are evolving towards higher energy density, higher safety, and higher intelligence. Existing battery signal detection methods suffer from low signal accuracy and the acquisition wiring harnesses occupy a significant amount of internal battery space. Summary of the Invention

[0003] In view of this, the purpose of this application is to propose a battery cell and a battery pack to solve the problems of low accuracy of existing signal acquisition and the occupation of internal battery space by the acquisition harness.

[0004] To achieve the above objectives, the first aspect of this application provides a battery cell, comprising:

[0005] The housing includes an open end and a closed end, and a signal acquisition unit is provided inside the closed end; A cover plate covers the opening end and, together with the housing, forms an accommodating space. The pole is insulated and connected to the cover plate; A connector is located inside the housing, and the connector includes a first connecting portion and a second connecting portion; An electrode assembly is disposed within the receiving space. The electrode assembly includes at least one main body, with a collection tab and a power tab respectively extending from opposite ends of the main body. The power tab is electrically connected to the first connecting part, the first connecting part is electrically connected to the electrode post, the collection tab is electrically connected to the second connecting part, and the second connecting part is electrically connected to the signal acquisition part. The signal acquisition part is used to collect the electrical signal of the electrode assembly and send the electrical signal to the battery management unit.

[0006] In some embodiments, the main body includes two oppositely arranged sides, the battery cell includes two oppositely arranged connectors, each connector is in contact with one of the sides, the second connection portion of each connector is located on the same side of the main body, the signal acquisition unit is connected to the second connection portions of both connectors, and the signal acquisition unit is used to acquire the electrical signal between the two second connection portions.

[0007] In some embodiments, the device further includes a data acquisition circuit board and a sealing terminal. The data acquisition circuit board is located on the side of the sealed end away from the main body. The signal acquisition unit includes a first connection area and a second connection area. The first connection area is connected to the second connection area, and the second connection area is electrically connected to the data acquisition circuit board through the sealing terminal.

[0008] In some embodiments, the system further includes a data acquisition circuit board disposed on the side of the closed end near the main body. The signal acquisition unit includes a first connection area and a second connection area, wherein the first connection area is connected to the second connection area and the second connection area is electrically connected to the data acquisition circuit board.

[0009] In some embodiments, the battery cell further includes at least one temperature sensor, which is located at one end of the main body near the signal acquisition unit and electrically connected to the acquisition circuit board.

[0010] In some embodiments, the signal acquisition unit further includes a signal bending region located between the first connection region and the second connection region, and the battery cell further includes an acquisition bracket located within the housing and covering the signal bending region.

[0011] In some embodiments, the surface of the acquisition bracket near the closed end is the acquisition surface, the surface of the second connection area near the closed end is the connection surface, the acquisition surface is flush with the connection surface, or the acquisition surface is located on the side of the connection surface away from the closed end.

[0012] In some embodiments, the connector further includes a busbar connection portion, and the connector further includes a first bend portion and a second bend portion. The busbar connection portion is bendably connected to the first connection portion through the first bend portion, and is bendably connected to the second connection portion through the second bend portion. The battery cell also includes a bending bracket, which is disposed on the surface of the cover plate facing the main body or the surface of the closed end facing the main body. The bending bracket covers the first bending portion and the second bending portion, and the bending bracket abuts against the end face of the main body.

[0013] In some embodiments, the bent support located between the main body and the closed end is a base support, the surface of the base support near the closed end is the base frame surface, the collecting surface and the connecting surface are flush with the base frame surface, or the collecting surface and the connecting surface are located on the side of the base frame surface away from the closed end; And / or, the orthographic projection of the acquisition circuit board on the first plane does not coincide with the orthographic projection of the base surface on the first plane, where the first plane is the plane containing the end face of the main body near the closed end.

[0014] Based on the same inventive concept, this application also provides a battery pack, including the battery cells described in any of the first aspects above.

[0015] As can be seen from the above description, the battery cell and battery pack provided in this application include a battery cell comprising a housing, the housing comprising an open end and a closed end, a signal acquisition unit being provided inside the closed end, a cover plate covering the open end and forming an accommodating space with the housing; an electrode post being insulatedly connected to the cover plate; a connector being located inside the housing, the connector comprising a first connecting part and a second connecting part; an electrode assembly being disposed within the accommodating space, the electrode assembly comprising at least one main body, with a collection tab and a power tab respectively extending from opposite ends of the main body, the power tab being electrically connected to the first connecting part, the first connecting part being electrically connected to the electrode post, the collection tab being electrically connected to the second connecting part, the second connecting part being electrically connected to the signal acquisition unit, the signal acquisition unit being used to collect electrical signals from the electrode assembly and send the electrical signals to the battery management unit. In this way, by setting up a "single-sided pole + dual-sided tabs with different functions + built-in signal acquisition unit", the charging and discharging path of the battery cell is completely physically isolated from the signal acquisition path. This ensures that the strong electromagnetic field generated during charging and discharging will not couple to the acquisition path, thus completely avoiding electromagnetic interference of high-power current on the acquired signal from the root, improving the accuracy of the acquired signal, providing reliable data support for the battery management system, and eliminating the need for additional wiring harnesses and connectors, without increasing the size of the battery cell. In this way, the accuracy of the acquired signal can be improved without increasing the size of the battery cell. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1A This is a schematic diagram of the exploded structure of a single battery cell according to an embodiment of this application; Figure 1B This is a schematic diagram of a battery cell in an embodiment of this application with the casing removed but the sealed end retained. Figure 1C This is an exemplary structural diagram of a battery cell after removing the casing and body according to an embodiment of this application. Figure 1D This is another exemplary structural diagram of a battery cell after removing the casing and body according to an embodiment of this application. Figure 1E Included with instruction manual Figure 1D A magnified view of part M in the diagram; Figure 1F This is another exemplary structural diagram of a battery cell after removing the casing and body according to an embodiment of this application. Figure 1GThis is another exemplary structural diagram of a battery cell after removing the casing and body according to an embodiment of this application. Figure 1H Included with instruction manual Figure 1G A magnified view of N in the diagram; Figure 1I This is a schematic diagram of the connector in an embodiment of this application when it is not assembled; Figure 1J This is a schematic diagram of the assembled connector according to an embodiment of this application; Figure 1K This is a schematic diagram of the structure of two main bodies connected to the connector but not in the core according to an embodiment of this application; Figure 2 This is a flowchart illustrating the battery cycle life prediction method according to an embodiment of this application. Figure 3 This is a schematic diagram illustrating the principle of the battery cycle life prediction method according to an embodiment of this application; Figure 4 This is a test graph showing the change in internal resistance of a square aluminum-cased battery during cycling.

[0018] In the diagram: 100, housing; 110, open end; 120, closed end; 200, cover plate; 300, pole; 400, connector; 410, busbar connection; 411, busbar sub-section; 420, first connection; 421, first sub-section; 430, second connection; 431, second sub-section; 500, electrode assembly; 510, main body; 520, power tab; 530, acquisition tab; 600, bending bracket; 610, base surface; 700, signal acquisition section; 710, first connection area; 720, second connection area; 721, connection surface; 730, signal bending area; 800, acquisition circuit board; 900, acquisition bracket; 910, acquisition surface. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0020] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] It should be noted that, unless otherwise defined, the terms "parallel" and "perpendicular" as used in the embodiments of this application include the described situation and situations similar to the described situation, where the range of similar situations is within an acceptable deviation range, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, where the acceptable deviation range for approximate parallelism can be, for example, within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, where the acceptable deviation range for approximate perpendicularity can also be, for example, within 5°.

[0022] With the rapid development of new energy vehicles and the energy storage industry, lithium-ion battery systems are evolving towards higher energy density, higher safety, and higher intelligence. Blade batteries, with their high space utilization, have become the mainstream technology for power batteries and energy storage batteries.

[0023] Existing blade battery modules and battery pack systems generally adopt an architecture of "single-sided terminal post + single-sided tab + battery pack-level battery management system data acquisition": the battery cell has a tab and terminal post at only one end, and all charging and discharging current and signal acquisition are achieved through the terminal post. Multiple battery cells are connected in series / parallel through a busbar within the module, and acquisition lines are welded to the busbar. After acquiring electrical signals, the acquisition lines transmit the electrical signals to the battery management system at the battery pack level. Temperature sensors are attached to the outer surface of the battery casing or the outer surface of the busbar.

[0024] However, this approach has some obvious drawbacks: Severe signal interference: The signal acquisition line is arranged in parallel with the high-power bus. The strong electromagnetic field generated during charging and discharging will couple to the acquisition line, causing large fluctuations and distortions in the acquired signal. Severe signal interference leads to signal distortion and low monitoring accuracy (voltage acquisition error is usually ≥50mV), which makes it impossible to provide reliable data support for the battery management system.

[0025] Low detection accuracy: The voltage signal must pass through multiple components such as busbars, acquisition lines, and connectors before reaching the battery management system, resulting in contact resistance and transmission loss, leading to large measurement errors. Furthermore, the external temperature sensor results in a 2-5°C temperature difference between the externally acquired temperature and the internal temperature of the battery cell, and it cannot monitor the temperature distribution differences across the battery cell's terminals. It also cannot directly acquire the battery cell's voltage signal, creating a monitoring blind zone. This means that thermal runaway warnings can only be issued a few minutes in advance, failing to allow sufficient time for safe intervention.

[0026] Complex wiring harnesses: Each battery cell requires at least one voltage acquisition line, and every 2-3 battery cells require one temperature acquisition line. Therefore, a 16-cell blade battery module typically requires more than 30 wiring harnesses and more than 20 connectors. The complex wiring harnesses occupy a lot of space, resulting in an increase in the size and weight of the module, as well as low assembly efficiency and a high failure rate of poor contact and short circuits.

[0027] Upgrading is difficult: To improve detection accuracy or add detection functions, it is necessary to redesign the battery cell structure, module wiring harness and battery management system, which involves a lot of changes, high costs and long cycles.

[0028] Performance bottleneck: The single-sided tab design results in a long current transmission path inside the battery cell, uneven current distribution in large-size battery cells, large ohmic heat loss, low charge and discharge efficiency, and heat concentrated at the tab end, which can easily lead to thermal runaway.

[0029] Therefore, how to provide a battery structure with high detection accuracy without increasing battery size is an urgent problem to be solved.

[0030] Based on this, see Figure 1A and Figure 1B As shown, this application provides a single battery cell, comprising: The housing 100 includes an open end 110 and a closed end 120, and a signal acquisition unit 700 is provided inside the closed end 120. A cover plate 200 covers the opening end 110 and, together with the housing 100, forms an accommodating space. The pole post 300 is insulatedly connected to the cover plate 200; A connector 400 is located inside the housing 100, and the connector 400 includes a first connecting portion 420 and a second connecting portion 430; An electrode assembly 500 is disposed within the receiving space. The electrode assembly 500 includes at least one main body 510. A data acquisition tab 530 and a power tab 520 are respectively led out from opposite ends of the main body 510. The power tab 520 is electrically connected to the first connecting portion 420, and the first connecting portion 420 is electrically connected to the electrode post 300. The data acquisition tab 530 is electrically connected to the second connecting portion 430, and the second connecting portion 430 is electrically connected to the signal acquisition unit 700. The signal acquisition unit 700 is used to acquire the electrical signal of the electrode assembly 500 and send the electrical signal to the battery management unit.

[0031] Specifically, the housing 100 includes an open end 110 and a closed end 120. A signal acquisition unit 700 is provided inside the closed end 120, that is, on the end face of the closed end 120 near the open end 110. The signal acquisition unit 700 is communicatively connected to the battery management system corresponding to the battery cell, and can then send the acquired electrical signals of the electrode assembly 500 to the battery management unit.

[0032] For example, the signal acquisition unit 700 and the battery management system can be electrically connected via a wiring harness or a dedicated interface, or they can be wirelessly connected. For instance, the signal acquisition unit 700 can be connected wirelessly via Bluetooth, Wi-Fi, ultra-wideband, cellular network, or near-field communication.

[0033] The specific connection method between the signal acquisition unit 700 and the battery management system is not limited and can be selected based on actual needs. In this embodiment, the signal acquisition unit 700 and the battery management system communicate wirelessly. In this way, the signal acquisition unit 700 can send the acquired electrical signals to the battery management unit, and the wireless connection does not occupy the internal space of the battery cell, does not increase the size of the battery cell, and avoids faults such as poor contact and short circuits caused by the presence of wiring harnesses.

[0034] The electrical signals acquired by the signal acquisition unit 700 can be voltage data, current data, temperature data, and / or resistance change data, etc. Accordingly, the signal acquisition unit 700 can be a voltage acquisition device, a current acquisition device, a temperature acquisition device, a resistance acquisition device, etc.

[0035] The cover plate 200 covers the opening end 110 and, together with the housing 100, forms an accommodating space. An insulated terminal post 300 is insulatedly connected to the cover plate 200. The terminal post 300 includes a positive terminal post and a negative terminal post.

[0036] An electrode assembly 500 is disposed within the receiving space. The electrode assembly 500 includes at least one body 510, which includes a plurality of insulatingly disposed positive electrode plates, separators, and negative electrode plates. Exemplarily, the positive electrode plates, separators, and negative electrode plates are stacked sequentially to form the body 510.

[0037] The main body 510 has a sampling tab 530 and a power tab 520 extending from its opposite ends. The sampling tab 530 includes a positive tab and a negative tab. Correspondingly, the power tab 520 also includes a positive tab and a negative tab. Two positive tabs are extended from each end of the positive electrode, one serving as the sampling tab 530 and the other as the power tab 520. Two negative tabs are extended from each end of the negative electrode, one serving as the sampling tab 530 and the other as the power tab 520. All sampling tabs 530 are located on the same side of the main body 510, and all power tabs 520 are located on the opposite side of the main body 510.

[0038] Thus, the main body 510 of the single cell described in this application has tabs at both ends, namely the acquisition tab 530 and the power tab 520. Through the structure of tabs leading out from both ends, the current is evenly distributed inside the single cell, the transmission path is shorter, the internal resistance is lower, the heat generation is less, and the safety performance of the battery is improved.

[0039] In addition, during the charging and discharging process, the heat generated by a single battery cell is concentrated near the tabs. Compared to a battery cell where the tabs of the same polarity are only led out from one end of the main body 510, in the battery cell of this embodiment, the tabs of the same polarity are led out from opposite ends of the main body 510, so the heat generation of the battery cell is more dispersed, which is beneficial to the heat dissipation of the battery.

[0040] The power tab 520 is electrically connected to the first connecting part 420, and the first connecting part 420 is electrically connected to the terminal post 300. Thus, the power tab 520 is electrically connected to the terminal post 300 through the first connecting part 420, and the power tab 520 undertakes the transmission of all charging and discharging power of the battery cell.

[0041] The acquisition tab 530 is electrically connected to the second connection part 430, and the second connection part 430 is electrically connected to the signal acquisition part 700. Thus, the acquisition tab 530 is electrically connected to the signal acquisition part 700 through the second connection part 430. Thus, the acquisition tab 530 is only used for outputting electrical signals, and the acquisition tab 530 is not connected to the terminal post 300. Therefore, the acquisition tab 530 does not need to bear the charging and discharging power transmission of the battery cell.

[0042] In this application, although tabs are provided at both opposite ends of the main body 510, the acquisition tab 530 at one end is only used for electrical signal output and does not undertake charging and discharging power transmission, while the power tab 520 at the other end only undertakes the full charging and discharging power transmission of the battery cell and is not used for electrical signal output. In this way, the acquisition tab 530 and the power tab 520 independently undertake different functions. Based on the two different paths of the acquisition tab 530 and the power tab 520, the charging and discharging path of the battery cell is completely physically isolated from the signal acquisition path, ensuring that the strong electromagnetic field generated during charging and discharging will not couple to the acquisition path, thereby completely avoiding electromagnetic interference of high-power current on the acquisition signal, improving the accuracy of the acquisition signal, and providing reliable battery cell-level data support for the battery management system.

[0043] Furthermore, the signal acquisition unit 700 is directly housed inside the closed end 120, and it directly transmits the electrical signals from the electrode assembly 500 acquired by the signal acquisition unit 700 to the battery management system. This eliminates the need for additional signal acquisition lines and connectors within the battery cell, and the signal acquisition unit 700 occupies virtually no internal space within the battery cell, thus not increasing its overall size. Moreover, compared to external signal acquisition devices, the signals acquired by the built-in signal acquisition unit 700 are more accurate.

[0044] Therefore, in this application, by setting up a "single-sided electrode post 300 + dual-sided tabs with different functions + built-in signal acquisition unit 700", the charging and discharging path of the battery cell is completely physically isolated from the signal acquisition path. This ensures that the strong electromagnetic field generated during charging and discharging will not couple to the acquisition path, fundamentally avoiding electromagnetic interference from high-power current on the acquired signal, improving the accuracy of the acquired signal, and providing reliable data support for the battery management system. Furthermore, there is no need to set up extra wiring harnesses and connectors, and the size of the battery cell is not increased. Thus, the accuracy of the acquired signal can be improved without increasing the size of the battery cell.

[0045] In some embodiments, see continue to see Figure 1B and Figure 1C As shown, the main body 510 includes two oppositely arranged sides, and the battery cell includes two oppositely arranged connectors 400. Each connector 400 contacts one of the sides, and the second connection portion 430 of each connector 400 is located on the same side of the main body 510. The signal acquisition unit 700 is connected to the second connection portions 430 of both connectors 400, and the signal acquisition unit 700 is used to acquire the electrical signal between the two second connection portions 430.

[0046] Specifically, the battery cell includes two connectors 400 arranged opposite to each other. Each connector 400 is in contact with a side surface. The second connecting portion 430 of each connector 400 is located on the same side of the main body 510, and the first connecting portion 420 of each connector 400 is also located on the same side of the main body 510.

[0047] Thus, by using the two connectors 400, electrodes of the same polarity located on different sides can be made conductive. For example, as Figure 1B As shown, assuming Figure 1B The left-hand tab is the positive tab (including the positive power tab 520 located on the cover plate 200 side and the positive acquisition tab 530 located on the closed end 120 side), and the right-hand tab is the negative tab (including the negative power tab 520 located on the cover plate 200 side and the negative acquisition tab 530 located on the closed end 120 side). Therefore, the tab located on... Figure 1B The connector 400 on the left side can connect the positive power tab 520 and the positive acquisition tab 530 to form a complete bus circuit. Located in Figure 1B The connector 400 on the right can connect the negative power tab 520 and the negative acquisition tab 530 to form a complete bus circuit.

[0048] In this application, by setting the connector 400 to form a connected current-collecting tab 530 and power tab 520 of the same polarity into a connected current-collecting circuit, the first and last conduction of the battery cell is realized, thereby making the current evenly distributed inside the battery cell, with a shorter transmission path, lower internal resistance, less heat generation, and improved battery safety performance.

[0049] The signal acquisition unit 700 is connected to the second connection portion 430 of both connectors 400. The signal acquisition unit 700 is used to acquire the electrical signal between the two second connection portions 430. In this way, the signal acquisition unit 700 can accurately acquire the electrical signal between the two second connection portions 430, that is, accurately acquire the electrical signal between the positive acquisition tab 530 and the negative acquisition tab 530. Then, based on the electrical signal, the changes of related parameters such as voltage, current and / or resistance between the positive acquisition tab 530 and the negative acquisition tab 530 can be accurately monitored, so as to provide accurate cell-level data support for the battery management system.

[0050] For example, see Figure 1C As shown, the signal acquisition unit 700 can be connected to both of the second connection units 430 via acquisition lines to acquire the electrical signal between the two second connection units 430.

[0051] In this application, in order to further reduce the use of acquisition lines and to further improve the detection accuracy and detection stability of the signal acquisition unit 700, a signal acquisition unit 700 with a novel structure is provided.

[0052] In some embodiments, see Figure 1D , Figure 1E and Figure 1F As shown, the battery cell also includes a data acquisition circuit board 800, which is located on the side of the closed end 120 near the main body 510. The signal acquisition unit 700 includes a first connection area 710 and a second connection area 720. The first connection area 710 is connected to the second connection part 430, and the second connection area 720 is electrically connected to the data acquisition circuit board 800.

[0053] Specifically, the first connection area 710 can be directly and simultaneously connected to both second connection parts 430 without a data acquisition cable. This results in a larger connection area between the first connection area 710 and the two second connection parts 430, improving the detection accuracy and stability of the signal acquisition unit 700. Furthermore, the direct connection of the first connection area 710 to the second connection parts 430 without a data acquisition cable further reduces the use of data acquisition cables, preventing acquisition failures due to wiring harness malfunctions.

[0054] The second connection area 720 is electrically connected to the acquisition circuit board 800, and the acquisition circuit board 800 is communicatively connected to the battery management system. Thus, the electrical signal acquired by the signal acquisition unit 700 can be directly sent to the acquisition circuit board 800, and the acquisition circuit board 800 can directly send the electrical signal to the battery management system. Alternatively, the acquisition circuit board 800 can perform basic filtering, amplification, and / or analog-to-digital conversion on the electrical signal and then send the processed data to the battery management system.

[0055] In addition, the second connection area 720 is directly electrically connected to the acquisition circuit board 800 without passing through a wiring harness, which can reduce the transmission loss of the wiring harness and ensure the accuracy of the transmitted electrical signal.

[0056] The acquisition circuit board 800 can be located on the side of the closed end 120 close to the main body 510. In this way, both the acquisition circuit board 800 and the signal acquisition unit 700 are located inside the housing 100, which can avoid interference from external factors on the signals acquired by the acquisition circuit board 800 and the signal acquisition unit 700, and improve the accuracy of the acquired and transmitted signals.

[0057] In some embodiments, the battery cell further includes a data acquisition circuit board 800 and a sealing terminal (not shown in the figure). The data acquisition circuit board 800 is disposed on the side of the closed end 120 away from the main body 510. The signal acquisition unit 700 includes a first connection area 710 and a second connection area 720. The first connection area 710 is connected to the second connection part 430, and the second connection area 720 is electrically connected to the data acquisition circuit board 800 through the sealing terminal.

[0058] Specifically, the acquisition circuit board 800 can also be located on the side of the closed end 120 away from the main body 510, that is, on the outside of the housing 100. This makes it convenient to replace or repair the acquisition circuit board 800 during actual use, and the replacement or repair of the acquisition circuit board 800 will not affect the internal structure of the battery cell, which is convenient for actual use.

[0059] By housing the signal acquisition unit 700 inside the housing 100, the accuracy of the acquired electrical signals can be improved. The second connection area 720 of the signal acquisition unit 700 is electrically connected to the acquisition circuit board 800 through a sealed terminal. In this way, the signal acquisition unit 700 can transmit the acquired electrical signals to the acquisition circuit board 800 without the need for transmission through the acquisition wiring harness, thus avoiding signal transmission failure due to acquisition wiring harness failure.

[0060] In some embodiments, when the acquisition circuit board 800 is located on the side of the closed end 120 near the main body 510, the battery cell further includes at least one temperature sensor (not shown in the figure), which is located on the end of the main body 510 near the signal acquisition unit 700 and electrically connected to the acquisition circuit board 800.

[0061] Specifically, multiple temperature sensors can be provided, and the multiple temperature sensors are evenly arranged at one end of the main body 510 near the signal acquisition unit 700. In this way, multiple temperature sensors can collect the temperature at various positions at the end of the main body 510, providing accuracy and uniformity of temperature acquisition.

[0062] Furthermore, since the heat of a single battery cell tends to concentrate at the tab end, multiple temperature sensors can also be partially disposed on the side of the acquisition tab 530 near the main body 510. In this way, the temperature sensors can also accurately acquire the temperature of the acquisition tab 530, thereby more accurately acquiring the temperature of the heat concentration area of ​​the single battery cell, providing key and accurate temperature data for the thermal runaway early warning of the battery management system.

[0063] The temperature sensor is also electrically connected to the acquisition circuit board 800. In this way, the temperature sensor can directly transmit the acquired temperature data to the acquisition circuit board 800. The acquisition circuit board 800 can directly send the received temperature data to the battery management system, or the acquisition circuit board 800 can perform basic filtering, amplification and / or analog-to-digital conversion on the received temperature data and then send the processed data to the battery management system, providing key and accurate temperature data for the thermal runaway early warning of the battery management system.

[0064] Furthermore, a gas sensor (not shown in the figure) can also be installed on the acquisition circuit board 800 to monitor the gas concentration inside the battery cell, so as to monitor whether there is gas leakage inside the battery cell in real time, and further improve the accuracy and timeliness of fault warning.

[0065] Furthermore, a strain sensor (not shown in the figure) can also be installed on the acquisition circuit board 800 to monitor the expansion and deformation inside the battery cell in real time, thereby improving the early warning of battery cell failure.

[0066] In some embodiments, see Figure 1G and Figure 1H As shown, the signal acquisition unit 700 further includes a signal bending region 730, which is located between the first connection region 710 and the second connection region 720. The battery cell also includes an acquisition bracket 900, which is located inside the housing 100 and covers the signal bending region 730.

[0067] Specifically, the signal bending region 730 is located between the first connection region 710 and the second connection region 720, and the signal bending region 730 is a transition region between the first connection region 710 and the second connection region 720. The existence of the signal bending region 730 facilitates the bending of the signal acquisition unit 700, allowing the signal acquisition unit 700 to be connected to both the second connection part 430 and the acquisition circuit board 800 simultaneously, which facilitates signal acquisition and transmission while reducing the space occupied by the signal acquisition unit 700.

[0068] For example, the signal bending region 730 may be made of a flexible conductive material to facilitate the bending and installation of the signal acquisition unit 700.

[0069] The battery cell also includes a data acquisition bracket 900, which is located within the housing 100 and covers the signal bending area 730. Further, the data acquisition bracket 900 covers the signal bending area 730 and extends to the side of the second connecting portion 430 near the main body 510. The data acquisition bracket 900 can abut or connect with the side of the second connecting portion 430 near the main body 510, or it can abut or connect with the side of the main body 510 near the second connecting portion 430, to fix the data acquisition bracket 900.

[0070] It is worth noting that the acquisition bracket 900 should be positioned to avoid the acquisition tab 530 to prevent adverse effects on the acquisition tab 530. The acquisition bracket 900 can only be connected to the position on the second connecting part 430 where the acquisition tab 530 is not connected, and the acquisition bracket 900 can only be connected to the area on the main body 510 where the acquisition tab 530 is not provided.

[0071] Furthermore, the collection bracket 900 is made of insulating material.

[0072] The acquisition bracket 900 covers the signal bending area 730. The presence of the acquisition bracket 900 can protect the end face and the tab of the main body 510, and prevent the signal bending area 730 from damaging the end face and the tab of the main body 510.

[0073] In some embodiments, the surface of the acquisition bracket 900 near the closed end 120 is the acquisition surface 910, and the surface of the second connection area 720 near the closed end 120 is the connection surface 721. The acquisition surface 910 is flush with the connection surface 721, or the acquisition surface 910 is located on the side of the connection surface 721 away from the closed end 120.

[0074] Specifically, the acquisition surface 910 is flush with the connection surface 721, or the acquisition surface 910 is located on the side of the connection surface 721 away from the closed end 120. This ensures that the acquisition surface 910 does not protrude from the connection surface 721, and thus the acquisition bracket 900 does not occupy more space than the signal acquisition unit 700. This reduces the space occupied by the main body 510 and ensures that the volume of the battery cell is not increased.

[0075] In some embodiments, see continue to see Figure 1C , Figure 1I and Figure 1JAs shown, the connector 400 further includes a busbar connection portion 410, and the connector 400 also includes a first bending portion and a second bending portion. The busbar connection portion 410 is bendably connected to the first connection portion 420 through the first bending portion, and is bendably connected to the second connection portion 430 through the second bending portion. The battery cell also includes a bending bracket 600, which is disposed on the surface of the cover plate 200 facing the main body 510 or the surface of the closed end 120 facing the main body 510. The bending bracket 600 covers the first bending portion and the second bending portion, and the bending bracket 600 abuts against the end face of the main body 510.

[0076] Specifically, the connector 400 further includes a busbar connection 410, a first bending portion, and a second bending portion. The busbar connection 410 is bendably connected to the first connection portion 420 via the first bending portion and to the second connection portion 430 via the second bending portion. In this way, the first connection portion 420, the busbar connection 410, and the second connection portion 430 connect the acquisition tab 530 and the power tab 520 to form a connected busbar circuit, realizing the end-to-end conduction of the battery cell. This results in a uniform current distribution within the battery cell, a shorter transmission path, lower internal resistance, less heat generation, and improved battery safety performance.

[0077] The first connecting part 420, the busbar connecting part 410, the second connecting part 430, the first bending part and the second bending part can be integrally formed, which makes the structural stability of the connecting part 400 good. On the basis of forming a busbar circuit, it can also limit the main body 510, suppress the deformation or expansion of the main body 510 caused by gas generation during charging and discharging, and improve the structural stability and safety of the battery cell.

[0078] Meanwhile, the first and second bending portions enable the first connecting portion 420 and the second connecting portion to be bent into the busbar connecting portion 410, which facilitates the bending of the first connecting portion 420 and the second connecting portion 430 to a plane parallel to the end face of the main body 510 during actual battery cell assembly, thus facilitating the connection of the first connecting portion 420 and the second connecting portion 430 with the corresponding acquisition tab 530 or power tab 520.

[0079] See Figure 1I , Figure 1J and Figure 1KAs shown, the first connecting part 420 includes a first sub-part 421, the second connecting part 430 includes two spaced-apart second sub-parts 431, and the busbar connecting part 410 includes two busbar sub-parts 411. One of the first sub-parts 421 is connected to one of the second connecting parts 430 through one of the busbar sub-parts 411, and the other first sub-part 421 is connected to another of the second connecting parts 430 through the other busbar sub-part 411.

[0080] The battery cell includes two main bodies 510, two first sub-parts 421 for connecting the power tabs 520 led out from the two main bodies 510 respectively, and two second sub-parts 431 for connecting the acquisition tabs 530 led out from the two main bodies 510 respectively.

[0081] In the actual assembly of battery cells, each connector 400 is as follows: Figure 1I As shown. At this time, the two second sub-parts 431 are located on both sides of the first connecting part 420. Then, as... Figure 1K As shown, the first connecting part 420 is connected to the power tab 520. After the connection is fixed, the two bus sub-parts 411 are rotated towards the first connecting part 420, causing the two first bending parts to bend and thus bringing the two main bodies 510 together. At this time, the two first sub-parts 421 are close to each other. Then, the second bending part is bent so that both first sub-parts 421 are parallel to the end face of the main body 510. Figure 1J As shown. Finally, the connection between the first sub-unit 421 and the acquisition tab 530 is completed.

[0082] The battery cell using the connector 400 of this embodiment can have its internal current flow to the first connector 420 and the second connector 430 located on opposite sides of the electrode assembly 500, and then be transmitted to the terminal post 300 after being combined through the current-combining connector 410 with low internal resistance. This helps to shorten the charge transmission path inside the battery cell, reduce DC internal resistance, improve charging and discharging efficiency, and make the battery cell perform better in high-current charging and discharging scenarios.

[0083] Meanwhile, the connector 400 in this embodiment includes a first connecting part 420, a second connecting part 430 and a busbar connecting part 410, which has a large effective heat dissipation area, so that the heat generated by the electrode assembly 500 can be quickly transferred from its interior to the external module structure, which can effectively suppress local overheating of the battery cell, improve thermal stability and reduce the risk of thermal runaway.

[0084] See also Figure 1CAs shown, the battery cell also includes a bending bracket 600. The bending bracket 600 is disposed on the surface of the cover plate 200 facing the main body 510 or the surface of the closed end 120 facing the main body 510. The bending bracket 600 covers the first bent portion and the second bent portion, and the bending bracket 600 abuts against the end face of the main body 510. Thus, the bending bracket 600 can, on the one hand, support the gap between the cover plate 200 and the main body 510, and the gap between the closed end 120 and the limb, preventing the cover plate 200 or the closed end 120 from collapsing due to its own weight or external pressure, and damaging the terminal post 300 or the connector 400. On the other hand, the bending bracket 600 can limit the longitudinal displacement of the first connecting portion 420 and the second connecting portion 430, preventing the first connecting portion 420 and the second connecting portion 430 from bending, warping or even breaking due to external pressure, welding stress or thermal expansion and contraction deformation, and ensuring the stability of the bus connection.

[0085] Specifically, the bending bracket 600 has a through hole inside. The first connecting part 420 and the second connecting part 430 extend out of the bending bracket 600 after passing through the through hole. The parts extending out of the bending bracket 600 are then connected to the acquisition tab 530 or the power tab 520. In this way, the bending bracket 600 can more effectively restrict the longitudinal displacement of the first connecting part 420 and the second connecting part 430.

[0086] In addition, the bending bracket 600 covers the first bending portion and the second bending portion, so that when the first bending portion and the second bending portion are bent, the bending bracket 600 can protect the main body 510 and prevent the first bending portion and the second bending portion from causing damage to the main body 510 when bending.

[0087] In some embodiments, see continue to see Figure 1G and Figure 1H As shown, the bent bracket 600 located between the main body 510 and the closed end 120 is the base bracket, the surface of the base bracket near the closed end 120 is the base frame surface 610, the collection surface 910 and the connecting surface 721 are flush with the base frame surface 610, or the collection surface 910 and the connecting surface 721 are located on the side of the base frame surface 610 away from the closed end 120; And / or, the orthographic projection of the acquisition circuit board 800 on the first plane does not coincide with the orthographic projection of the base surface 610 on the first plane, the first plane being the plane containing the end face of the main body 510 near the closed end 120.

[0088] Specifically, the sampling surface 910 is flush with the base frame surface 610, or the sampling surface 910 is located on the side of the base frame surface 610 away from the closed end 120, that is, the sampling surface 910 does not protrude from the base frame surface 610. In this way, the space for setting the base frame is sufficient to set the sampling bracket 900. The setting of the sampling bracket 900 will not occupy additional internal space of the battery cell and will not increase the volume of the battery cell.

[0089] The connecting surface 721 is flush with the base frame surface 610, or the connecting surface 721 is located on the side of the base frame surface 610 away from the closed end 120, that is, the connecting surface 721 will not protrude from the base frame surface 610. In this way, the space for setting the base bracket is sufficient to set the signal acquisition unit 700. The setting of the signal acquisition unit 700 will not occupy additional internal space of the battery cell and will not increase the volume of the battery cell.

[0090] Furthermore, when the acquisition circuit board 800 is installed, the connecting surface 721 is located on the side of the base surface 610 away from the closed end 120, and the orthographic projection of the acquisition circuit board 800 on the first plane does not coincide with the orthographic projection of the base surface 610 on the first plane. Thus, the base bracket protrudes from the signal acquisition part 700, meaning there is still a certain space between the signal acquisition part 700 and the closed end 120 of the housing 100. This space is just enough to accommodate the installation of the acquisition circuit board 800. In this way, the installation of the acquisition circuit board 800 will not occupy additional internal space of the battery cell and will not increase the volume of the battery cell.

[0091] In this application, the charging and discharging path and the signal acquisition path are completely physically isolated, thus completely avoiding electromagnetic interference from high-power current. Tests have shown that the voltage acquisition accuracy is improved to within ±10mV and the internal resistance detection accuracy is improved to ±0.5%, providing the most reliable cell-level data support for the battery management system.

[0092] Based on the signal acquisition unit 700, the voltage of the battery cell body can be directly acquired, as well as the temperature monitoring of multiple points at both ends and sides of the battery cell, eliminating all detection blind spots and improving detection accuracy.

[0093] Experimental tests show that, through the dual-sided tab full-area current-guiding design, the DC internal resistance of the battery cell is reduced by more than 25%, the temperature rise during 2CP constant power charging is reduced by about 25%, and the temperature rise during 2CP constant power discharging is reduced by more than 35%, significantly reducing the risk of thermal runaway.

[0094] The signal acquisition unit 700 is directly soldered onto the acquisition circuit board 800, without intermediate wiring harnesses or connectors, resulting in zero signal transmission loss.

[0095] This application also provides a battery pack, including the battery cells described in any of the above embodiments.

[0096] Specifically, the battery pack includes at least one battery cell as described in any of the above embodiments and a housing, the housing being used to house at least one of the battery cells.

[0097] The housing may include an upper housing and a lower housing, with the upper housing covering the lower housing to form a closed space for accommodating individual battery cells. The housing may contain one, two, or more individual battery cells, which may be arranged in any manner within the housing.

[0098] The battery cell or the battery pack can be a power source for an electrical device or an energy storage unit for an electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0099] The battery pack has the technical effects described in any of the above embodiments, and is not limited thereto.

[0100] In this application, since a signal acquisition unit 700 is provided inside the battery cell, the signal acquisition unit 700 can acquire the cell-level electrical signals in real time and send the electrical signals to the battery management system. The battery management system can perform thermal runaway early warning or cycle life prediction for the battery cell based on the received data and signals.

[0101] Currently, battery life prediction is mainly divided into two categories: physical modeling methods and data-driven methods. Physical modeling methods are based on equivalent circuit models or electrochemical models, which predict capacity decay by simulating the electrochemical reaction process inside the battery. Data-driven methods, on the other hand, extract measurable features such as voltage, current, and temperature, and combine them with machine learning models (such as support vector machines and long short-term memory networks) to establish a mapping relationship between health indicators and remaining life.

[0102] Internal resistance, as a key parameter highly correlated with capacity decay, has been widely used in lifetime prediction models. Studies have shown that direct current internal resistance (DCIR) can be measured in real time during charge and discharge, and its increase is directly related to battery aging mechanisms such as solid electrolyte interfacial film thickening, lithium deposition, and capacity decay. Therefore, DCIR, as a key parameter highly correlated with capacity decay, has been widely used in lifetime prediction models.

[0103] However, in practical applications, it has been found that the existing methods for predicting battery life based on DC internal resistance are not accurate enough. The battery often fails when the predicted remaining number of usable cycles is still relatively high, which is detrimental to the operational safety of the battery.

[0104] Based on this, the inventors of this application have discovered that existing methods for predicting battery life based on DC internal resistance, whether based on capacity decay or overall internal resistance growth, treat the battery as a homogeneous body and estimate its life from the perspective of the battery as a whole.

[0105] However, in reality, the failure process of a battery follows the evolutionary pattern of "point → local → whole". However, point failure and local failure of a battery cannot be reflected in the overall internal resistance of the battery in a timely manner. Therefore, there may be cases where the battery has partially failed, but the overall internal resistance of the battery still remains within a relatively stable range. Thus, the prediction of battery life based on the overall internal resistance of the battery is very inaccurate.

[0106] Based on this, this application proposes a battery cycle life prediction method from a local perspective, which realizes early failure warning and accurate prediction of remaining life by monitoring the internal resistance of different regions inside the battery.

[0107] For ease of description, the side of the battery cell closest to the cover plate 200 is referred to as the "cover plate side", the side closest to the closed end 120 is referred to as the "bottom plate side", the tab on the side closest to the cover plate 200, i.e. the power tab 520, is referred to as the "cover plate side tab", which includes the cover plate side positive tab and the cover plate side negative tab, and the tab on the side closest to the closed end 120, i.e. the collection tab 530, is referred to as the "bottom plate side tab", which includes the bottom plate side positive tab and the bottom plate side negative tab. The electrode assembly 500 is referred to as the "electrode group", and the battery cell is referred to as the "battery".

[0108] In the connector 400, the first connecting part 420 connected to the positive terminal is called the "cover plate side positive terminal connecting part", the first connecting part 420 connected to the negative terminal is called the "cover plate side negative terminal connecting part", the second connecting part 430 connected to the positive terminal is called the "bottom plate side positive terminal connecting part", the second connecting part 430 connected to the negative terminal is called the "bottom plate side negative terminal connecting part", the current collector connecting part 410 connected to the "cover plate side positive terminal connecting part" and the "bottom plate side positive terminal connecting part" is called the "positive current collector", and the current collector connecting part 410 connected to the "cover plate side negative terminal connecting part" and the "bottom plate side negative terminal connecting part" is called the "negative current collector".

[0109] Specifically, see Figure 2 and Figure 3 As shown, the battery cycle life prediction method provided in this application is executed by the battery management system, and the method specifically includes: Step S100: Obtain the first battery information at the current time of the battery, and obtain the second battery information after a preset time period; wherein, the first battery information includes a first connection voltage, the second battery information includes a second connection voltage, the first connection voltage and the second connection voltage are both voltages between the positive electrode connection part and the negative electrode connection part on the bottom plate side of the battery, the positive electrode connection part on the bottom plate side is connected to the positive electrode tab on the bottom plate side, and the negative electrode connection part on the bottom plate side is connected to the negative electrode tab on the bottom plate side; Step S200: Based on the first battery information and the second battery information, determine the first internal resistance and / or the second internal resistance, wherein the first internal resistance is the internal resistance of the cover plate side electrode group of the battery, and the second internal resistance is the internal resistance of the bottom plate side electrode group of the battery. Step S300: Determine the remaining usable number of cycles of the battery based on the first internal resistance and / or the second internal resistance.

[0110] Specifically, the battery in this application refers to a single battery in a battery pack and / or battery module, which may also be called a cell or battery unit.

[0111] In practical use, the system can acquire the first battery information at the current moment during each battery charge, and then acquire the second battery information after a preset time period. The preset time period is a pre-defined data acquisition period, which can be 10s, 20s, 30s, 40s, etc. The specific duration of the preset time period is not limited and is set based on actual testing requirements.

[0112] The first battery information is the battery information at the current moment, and the second battery information is the battery information after a preset time period.

[0113] The first battery information includes a first connection voltage, and the second battery information includes a second connection voltage. Both the first connection voltage and the second connection voltage are the voltages between the positive electrode connection portion and the negative electrode connection portion on the bottom plate side of the battery.

[0114] Specifically, the first connection voltage and the second connection voltage can be acquired by a signal acquisition unit 700 disposed between the positive terminal connection portion and the negative terminal connection portion on the bottom plate side of the battery. The signal acquisition unit 700 is disposed within the battery casing and electrically connected to the positive terminal connection portion and the negative terminal connection portion on the bottom plate side. The signal acquisition unit 700 is electrically connected, communicated with, or connected via Bluetooth to the battery management system, thus enabling it to transmit the acquired first and second connection voltages to the battery management system. For example, the signal acquisition unit 700 can be a voltage acquisition chip used to acquire the voltage between the positive terminal connection portion and the negative terminal connection portion on the bottom plate side.

[0115] In addition to the first connection voltage, the first battery information may also include other battery information. For example, the first battery information may also include a first battery voltage, which is the voltage between the positive and negative terminals of the battery, and the first battery voltage is the total voltage of the battery at the current moment.

[0116] The first battery information also includes a first battery current, which is the current between the positive and negative terminals of the battery. This first battery current is the total current of the battery at the current moment. Figure 3 The total current I shown 总 .

[0117] In addition to the second connection voltage, the second battery information may also include other battery information. For example, the second battery information may also include a second battery voltage, which is the voltage between the positive and negative terminals of the battery, and the first battery voltage is the total voltage of the battery after a preset period of time.

[0118] After acquiring the first battery information and the second battery information, a first internal resistance and / or a second internal resistance are determined based on the first battery information and the second battery information. The first internal resistance is the internal resistance of the cover plate side electrode assembly of the battery, and the second internal resistance is the internal resistance of the bottom plate side electrode assembly of the battery. That is, the first internal resistance represents the internal resistance of the top of the battery, and the second internal resistance represents the internal resistance of the bottom of the battery.

[0119] The electrode assembly includes multiple positive electrode plates, multiple separators, and multiple negative electrode plates, which are stacked or wound together to form the electrode assembly. For example, the electrode assembly includes positive electrode plates, separators, and negative electrode plates stacked sequentially, with the positive and negative electrode plates insulated from each other by the separators.

[0120] Finally, based on the first internal resistance and / or the second internal resistance, the remaining usable number of cycles of the battery is determined.

[0121] In practical applications, the remaining usable cycle count of a battery can be determined based solely on the first internal resistance. Alternatively, it can be determined solely on the second internal resistance. It can also be determined based on both the first and second internal resistances simultaneously. The choice depends on the specific circumstances and is not limited here.

[0122] For example, after multiple tests or uses, it is known that the top of the battery (i.e., the cover side) is more likely to fail first. Since failure at the top of the battery will cause a significant change in the internal resistance of the cover side electrode assembly, i.e., the first internal resistance, while the internal resistance of the bottom side electrode assembly, i.e., the second internal resistance, will hardly change or change very little, the internal resistance of the entire battery will not change significantly. At this time, the key to affecting the cycle life of the battery is the top of the battery, which is prone to failure. Therefore, the remaining usable cycle number of the battery can be accurately predicted based on the first internal resistance alone.

[0123] When multiple tests or uses reveal that the bottom of the battery (i.e., the base plate side) is more prone to failure, the failure at the bottom will cause a significant change in the internal resistance (second internal resistance) of the base plate side electrode assembly, while the internal resistance (first internal resistance) of the cover plate side electrode assembly will hardly change or change very little. Similarly, the overall internal resistance of the battery will not change significantly. In this case, the key factor affecting the battery's cycle life lies in the bottom of the battery, which is more prone to failure. Therefore, the remaining usable cycle count of the battery can be accurately predicted based solely on the second internal resistance.

[0124] If, after multiple tests or uses, it is still unknown whether the bottom or top of the battery is more likely to fail first, or if you want to monitor battery failure comprehensively and accurately, then you can determine the remaining usable cycle count of the battery based on both the first and second internal resistances, ensuring the comprehensiveness and accuracy of battery cycle life prediction.

[0125] In this application, since the first internal resistance is the internal resistance of the cover plate side electrode group of the battery and the second internal resistance is the internal resistance of the bottom plate side electrode group of the battery, the internal resistance of the cover plate side electrode group and the internal resistance of the bottom plate side electrode group of the battery can be obtained based on the first internal resistance and the second internal resistance. In this way, the entire battery is divided into two parts: the cover plate side electrode group and the bottom plate side electrode group. Compared with the internal resistance of the entire battery, the local internal resistance can more timely and accurately characterize the local changes inside the battery. Therefore, determining the remaining usable cycle number of the battery based on the two local internal resistances, namely the first internal resistance and / or the second internal resistance, is more accurate and timely.

[0126] Therefore, in this application, starting from a local perspective, the remaining usable number of cycles of the battery is determined based on the internal resistance of different regions inside the battery, namely the first internal resistance and / or the second internal resistance, which improves the accuracy and timeliness of battery cycle life prediction and realizes early failure warning and accurate prediction of remaining life of the battery.

[0127] In some embodiments, see Figure 3 As shown, based on the first battery information and the second battery information, the second internal resistance is determined, including: Based on the first battery voltage and the first connection voltage, the second current is determined, and the second current is the current between the bottom plate side connection part of the battery and the electrode group. The second internal resistance is determined based on the second connection voltage, the first connection voltage, and the second shunt current.

[0128] Specifically, based on Figure 3 It can be seen that during battery charging, current flows out from the positive terminal and into the negative terminal. The current flowing out from the positive terminal and the current flowing into the negative terminal are the same, both being the battery's total current at the current moment. Figure 3 The total current I shown 总 .

[0129] See Figure 3 When the battery is charging, current flows from the charger to the positive terminal, then through the positive terminal connection on the cover side and into the positive electrode plate. Then, inside the battery, lithium ions (Li)... + The current is conducted by moving from the positive electrode to the negative electrode (the equivalent current direction is also positive to negative), allowing the current to flow into the negative electrode plate.

[0130] After the current flows into the negative electrode, a portion of the current (i.e. Figure 3 As shown, I1 flows directly from the negative electrode plate into the negative electrode connection part on the cover plate side, and the other part of the current (i.e. Figure 3 As shown in Figure I2, the current flows from the negative electrode plate, through the negative electrode connection part on the bottom plate side, and then through the negative current busbar part before flowing into the negative electrode connection part on the cover plate side. The two parts of the current converge at the negative electrode connection part on the cover plate side (i.e., the current is...). Figure 3 The total current I shown 总 Then it flows into the negative terminal, and through the negative terminal it flows to the charger.

[0131] in this way, And I2 is the current between the base plate side connection and the electrode group, and the current I flowing through the busbar. 排 They are the same, therefore .

[0132] When determining the second current, i.e., the current I2 between the battery's base plate side connection and the electrode assembly, it is only necessary to determine the current I flowing through the busbar. 排 That's all.

[0133] Therefore, the second branch current is determined based on the first battery voltage and the first connection voltage. Specifically, the difference between the first battery voltage and the first connection voltage is first determined as the first difference, which is the voltage when current flows through the busbar.

[0134] Then, the first difference, i.e., the ratio of the voltage when current flows through the busbar to the internal resistance of the busbar, is determined as the current I flowing through the busbar. 排 I排 Similar to the second current, the ratio of the first difference to the internal resistance of the busbar is the second current.

[0135] The internal resistance of the busbar is an inherent resistance value known during the design and assembly of the busbar. The internal resistance of the busbar is the sum of the internal resistance of the positive busbar and the internal resistance of the negative busbar.

[0136] After determining the second branch current, the second internal resistance is determined based on the second connection voltage, the first connection voltage, and the second branch current.

[0137] Specifically, the difference between the second connection voltage and the first connection voltage is determined as the second difference, which is the voltage drop between the positive terminal connection and the negative terminal connection on the base plate side after a preset time period.

[0138] Then, the ratio of the second difference to the second partial current is determined as the second internal resistance, and the obtained second internal resistance is the internal resistance of the bottom plate side electrode group of the battery.

[0139] In this application, based on the voltage between the positive and negative terminals of the battery, i.e., the first battery voltage, and the voltage between the positive terminal connection and the negative terminal connection on the base plate side at different times, i.e., the first connection voltage and the second connection voltage, the internal resistance of the base plate side electrode assembly of the battery at the current time (i.e., the time corresponding to the first battery information) can be accurately determined. Thus, based on this internal resistance, the failure of the base plate side electrode assembly of the battery can be accurately assessed, providing a reliable data basis for assessing whether the battery has failed from a local perspective.

[0140] In some embodiments, determining the first internal resistance based on the first battery information and the second battery information includes: The difference between the first battery current and the second component current is determined as the first component current, which is the current between the battery cover side connection and the electrode group. The first internal resistance is determined based on the first shunt current and the first battery voltage.

[0141] Specifically, as mentioned above, Therefore, the current between the battery cover side connection and the electrode group is the first shunt current (i.e., Figure 3 In this context, I1) represents the difference between the first battery current and the second shunt current, i.e. .

[0142] Then, based on the voltage between the cover-side connection and the electrode assembly, and the first shunt current, the internal resistance of the cover-side electrode assembly can be calculated. Since the voltage between the cover-side connection and the electrode assembly is almost equal to the voltage between the positive and negative terminals, i.e., the first battery voltage, the first internal resistance is determined based on the first shunt current and the first battery voltage.

[0143] Specifically, the difference between the voltage of the second battery and the voltage of the first battery is determined as the third difference, which is the voltage drop between the positive and negative terminals after a preset time period.

[0144] The ratio of the third difference to the first partial current is determined as the first internal resistance, i.e., the internal resistance of the cover plate side electrode group.

[0145] In this application, based on the first battery current, the second branch current and the first battery voltage, the internal resistance of the cover plate side electrode group of the battery at the current moment (i.e., the moment corresponding to the first battery information) can be accurately determined. Then, based on the internal resistance, the failure of the cover plate side electrode group of the battery can be accurately evaluated, providing a reliable data basis for evaluating whether the battery has failed from a local perspective.

[0146] For specific implementation, please refer to [link / reference]. Figure 3 A signal acquisition unit 700 is provided between the positive terminal connection and the negative terminal connection on the bottom plate side to acquire voltage data; the battery is designed with a current collector structure, which has an inherent resistance R. 排。

[0147] The busbar structure includes a positive busbar and a negative busbar. The positive busbar is used to connect the positive terminal connection on the cover plate side and the positive terminal connection on the bottom plate side and can transmit current. The negative busbar is used to connect the negative terminal connection on the cover plate side and the negative terminal connection on the bottom plate side and can transmit current.

[0148] Battery cycle life prediction methods specifically include: Collect the first voltage data U output by the battery during the battery cycle. 总 (i.e., the first battery voltage), the current voltage data U2 (i.e., the first connection voltage) between the positive terminal connection and the negative terminal connection on the base plate side, based on Calculate the voltage U1 between the positive terminal connection and the negative terminal connection on the cover side, and the voltage U when current flows through the busbar. 排 .

[0149] Collect battery output current data I during battery cycling 总 (i.e., the first battery current), based on Calculate the current I2 (the second shunt current) between the bottom plate side connection and the electrode group, the current I1 (the first shunt current) between the cover plate side connection and the electrode group, and the current I when the busbar passes through. 排 .

[0150] Based on U 总 I 总 U1, U 排 I 2、 I1 and / or I 排The internal resistance of the cover plate side electrode group (i.e., the first internal resistance R1) and the internal resistance of the bottom plate side electrode group (i.e., the second internal resistance R2) are calculated. Finally, based on the first internal resistance and / or the second internal resistance, the remaining usable cycle number of the battery is determined.

[0151] In this application, based on It can be seen that the rate of change of R1 or R2 is greater than R. 总 The rate of change of R1 and R2 can more precisely reflect the changes in the local performance of the battery. In the process of battery failure from "point → local → whole", the detection of failure is moved from the whole failure detection to the local failure detection, which improves the accuracy and timeliness of battery cycle life prediction. It realizes early failure warning and accurate prediction of remaining life of the battery. Then, based on the prediction results, the battery management system can intervene in the battery in advance to improve the safety of battery use.

[0152] The following examples, using the test results of a square aluminum-cased battery LP71173207-300Ah, further demonstrate that R1 and R2 can more precisely reflect the changes in the local performance of the battery. Therefore, the battery life prediction results based on R1 and R2 are more accurate than those based on the overall resistance of the battery.

[0153] Signal acquisition unit 700 arrangement: The positive and negative electrode plates inside the battery are both connected to the positive electrode connection part on the cover plate side, the negative electrode connection part on the cover plate side, the positive electrode connection part on the bottom plate side, and the negative electrode connection part on the bottom plate side, respectively.

[0154] The positive electrode connection part on the cover plate side and the positive electrode connection part on the bottom plate side are connected by a positive busbar, and the negative electrode connection part on the cover plate side and the negative electrode connection part on the bottom plate side are connected by a negative busbar. A signal acquisition part 700 is provided between the positive electrode connection part on the bottom plate side and the negative electrode connection part on the bottom plate side.

[0155] The positive electrode connection part on the cover side, the negative electrode connection part on the cover side, the positive electrode connection part on the bottom plate side, the negative electrode connection part on the bottom plate side, the positive busbar, the negative busbar, and the signal acquisition part 700 are all provided with electronic insulation protection between themselves and the battery casing. Among them, the internal resistance design values ​​of the positive busbar and the negative busbar are 0.6mΩ and 0.4mΩ, respectively.

[0156] Cyclic operating conditions: Ambient temperature 25℃±2℃; Charging: Charge to 3.65V using 0.5CP constant power; let stand for 30 minutes; Discharge: Discharge at a constant power of 0.5 CP to 2.5V; let stand for 30 minutes; Cycle: The charging / discharging process alternates and repeats. One charging and discharging cycle is counted as one cycle; Data acquisition frequency: 10s / time.

[0157] Signal Acquisition Unit 700: Data acquisition frequency: 10s / time.

[0158] (1) Change of overall DC internal resistance (DCIR) of battery with the number of cycles: Take the voltage U of the battery terminal at the 10th second during the charging process. 总a Current I 总a The voltage U at the 30th second 总b Calculate the battery .

[0159] This step is repeated for each battery charging process. The relationship between DCIR and the number of cycles is recorded for each charging process, and a curve of battery charging DCIR versus number of cycles is plotted. Figure 4 As shown.

[0160] (2) Changes in local DCIR2 of the battery with the number of cycles: Take the voltage U at the battery terminals during the 10th second of the charging process. 总a Current I 总a The signal acquisition unit 700 acquires the voltage U at the 10th second. 2a Take the voltage U at the battery terminals during the 30th second of the charging process. 总b The signal acquisition unit 700 acquires the voltage U at the 30th second. 2b .

[0161] The voltage at the busbar at the 10th second can be calculated. Further calculations can yield the current at the busbar at this moment. ; Calculate the internal resistance of the base plate side electrode group .

[0162] This step is repeated for each battery charging process. The relationship between DCIR2 and the number of cycles is recorded for each charging process, and a curve of battery charging DCIR2 versus the number of cycles is plotted. Figure 4 As shown.

[0163] (3) Changes in local DCIR1 of the battery with the number of cycles: based on ,calculate Calculate the internal resistance of the cover plate side electrode assembly. .

[0164] This step is repeated for each battery charging process. The relationship between DCIR1 and the number of cycles is recorded for each charging process, and a curve of battery charging DCIR1 versus the number of cycles is plotted. Figure 4 As shown.

[0165] Depend on Figure 4It can be seen that the rate of change of the local impedance DCIR2 with the number of cycles is more obvious than the rate of change of the overall impedance DCIR. Therefore, for this battery, the battery life prediction result obtained by DCIR2, i.e. the second internal resistance, is more accurate than the battery life prediction result obtained based on the overall resistance of the battery.

[0166] Correspondingly, for some batteries, the cover plate side electrode assembly is more prone to failure. Therefore, the above test was performed on batteries with a more prone to failure on the cover plate side electrode assembly. The result of the battery internal resistance change test graph is that the local impedance DCIR1 changes more significantly with the number of cycles than the overall impedance DCIR. Therefore, for this battery, the battery life prediction result obtained by DCIR1, i.e. the first internal resistance, is more accurate than the battery life prediction result obtained based on the overall resistance of the battery.

[0167] Therefore, in actual testing, different prediction methods can be used for different batteries. The remaining usable cycle count can be determined based solely on the first internal resistance. Alternatively, it can be determined solely on the second internal resistance. Or, it can be determined based on both the first and second internal resistances simultaneously. The specific method chosen depends on the actual situation and is not limited here.

[0168] In some embodiments, determining the remaining usable number of cycles of the battery based on the first internal resistance and the second internal resistance includes: The first capacity retention rate is determined based on the mapping relationship between the first internal resistance and the first internal resistance capacity retention rate. The second capacity retention rate is determined based on the mapping relationship between the second internal resistance and the second internal resistance capacity retention rate. The minimum value between the first capacity retention rate and the second capacity retention rate is determined as the target capacity retention rate; Based on the mapping relationship between the target capacity retention rate and the number of capacity retention rate cycles, the remaining usable number of cycles for the battery is determined.

[0169] Specifically, the first internal resistance-capacity retention rate mapping relationship is a mapping relationship between the battery's first internal resistance and capacity retention rate during the charge-discharge process, determined based on historical tests. This mapping relationship is used to characterize the correspondence between the battery's first internal resistance and capacity retention rate during charge-discharge cycles. For example, the first internal resistance-capacity retention rate mapping relationship can exist in the form of a formula, curve, chart, or database.

[0170] The second internal resistance-capacity retention rate mapping relationship is a mapping relationship between the battery's second internal resistance and capacity retention rate during the charge-discharge process, determined based on historical tests. This mapping relationship is used to characterize the correspondence between the battery's second internal resistance and capacity retention rate during charge-discharge cycles. For example, the second internal resistance-capacity retention rate mapping relationship can exist in the form of a formula, curve, chart, or database.

[0171] Based on the mapping relationship between the first internal resistance and the first internal resistance capacity retention rate, the capacity retention rate of the battery corresponding to the first internal resistance can be determined, namely the first capacity retention rate. The first capacity retention rate is determined based on the internal resistance of the cover plate side electrode group of the battery and represents the capacity retention rate of the cover plate side electrode group.

[0172] Based on the mapping relationship between the second internal resistance and the capacity retention rate of the second internal resistance, the capacity retention rate of the battery corresponding to the second internal resistance, i.e., the second capacity retention rate, can be determined. The second capacity retention rate is determined based on the internal resistance of the bottom plate side electrode group of the battery and represents the capacity retention rate of the bottom plate side electrode group.

[0173] The minimum of the first capacity retention rate and the second capacity retention rate is determined as the target capacity retention rate. Thus, the target capacity retention rate is the minimum capacity retention rate of the battery determined based on the first internal resistance and the second internal resistance.

[0174] Finally, based on the mapping relationship between the target capacity retention rate and the number of capacity retention rate cycles, the remaining usable number of cycles for the battery is determined.

[0175] The capacity retention rate cycle number mapping relationship is a mapping relationship between the battery's capacity retention rate and the number of cycles during the charge and discharge process, determined based on historical testing experience. This mapping relationship is used to characterize the correspondence between the battery's capacity retention rate and the number of cycles during charge and discharge cycles. For example, the capacity retention rate cycle number mapping relationship can exist in the form of a formula, curve, chart, or database.

[0176] Based on the mapping relationship between the target capacity retention rate and the number of cycles for capacity retention rate, the target number of cycles corresponding to the target capacity retention rate can be determined. The difference between the preset termination cycle number and the target number of cycles is determined as the remaining usable cycle number of the battery. The remaining usable cycle number represents how many more cycles the battery can continue to cycle before reaching the preset termination cycle number, and is thus used to characterize the cycle life of the battery.

[0177] The preset termination cycle number is the maximum number of cycles for the battery determined based on historical testing experience or design specifications.

[0178] In this application, the remaining usable cycle count of the battery is determined based on the minimum of the first capacity retention rate and the second capacity retention rate, that is, based on the minimum of the capacity retention rate of the cover plate side electrode group and the capacity retention rate of the bottom plate side electrode group. In this way, the remaining usable cycle count of the battery can be accurately calculated based on the locally measured capacity retention rate, thereby improving the accuracy and timeliness of cycle life prediction.

[0179] In some embodiments, determining the remaining usable number of cycles of the battery based on the first internal resistance includes: The first capacity retention rate is determined based on the mapping relationship between the first internal resistance and the first internal resistance capacity retention rate. Based on the mapping relationship between the first capacity retention rate and the number of capacity retention rate cycles, the remaining usable number of cycles of the battery is determined.

[0180] Specifically, firstly, based on the mapping relationship between the first internal resistance and the first internal resistance capacity retention rate, the capacity retention rate of the battery corresponding to the first internal resistance, i.e. the first capacity retention rate, is determined based on the internal resistance of the cover plate side electrode group of the battery, and represents the capacity retention rate of the cover plate side electrode group.

[0181] Then, based on the mapping relationship between the first capacity retention rate and the number of capacity retention rate cycles, the remaining usable number of cycles of the battery is determined.

[0182] Based on the mapping relationship between the first capacity retention rate and the number of capacity retention rate cycles, the first number of cycles corresponding to the first capacity retention rate can be determined. The difference between the preset termination cycle number and the first number of cycles is determined as the remaining usable cycle number of the battery. The remaining usable cycle number is used to characterize how many more cycles the battery can continue to cycle before reaching the preset termination cycle number, and thus characterizes the cycle life of the battery.

[0183] In this application, the remaining usable number of cycles of a battery can be determined solely based on the first resistance, i.e., based on the first capacity retention rate corresponding to the first resistance. This reduces the computational load in the cycle life prediction process and improves the efficiency of the cycle life prediction process. It is applicable to the prediction of the cycle life of batteries whose cover plate side electrode assembly is prone to failure.

[0184] In some embodiments, determining the remaining usable number of cycles of the battery based on the second internal resistance includes: The second capacity retention rate is determined based on the mapping relationship between the second internal resistance and the second internal resistance capacity retention rate. Based on the second capacity retention rate and capacity retention rate cycle number mapping relationship, the remaining usable cycle number of the battery is determined.

[0185] Specifically, firstly, based on the mapping relationship between the second internal resistance and the capacity retention rate of the second internal resistance, the capacity retention rate of the battery corresponding to the second internal resistance, i.e., the second capacity retention rate, can be determined. The second capacity retention rate is determined based on the internal resistance of the bottom plate side electrode group of the battery and represents the capacity retention rate of the bottom plate side electrode group.

[0186] Then, based on the second capacity retention rate and capacity retention rate cycle number mapping relationship, the remaining usable cycle number of the battery is determined.

[0187] Based on the mapping relationship between the second capacity retention rate and the number of capacity retention rate cycles, the second number of cycles corresponding to the second capacity retention rate can be determined. The difference between the preset termination cycle number and the second number of cycles is determined as the remaining usable cycle number of the battery. The remaining usable cycle number is used to characterize how many more cycles the battery can continue to cycle before reaching the preset termination cycle number, and thus characterizes the cycle life of the battery.

[0188] In this application, the remaining usable number of cycles of a battery can be determined solely based on the second resistance, i.e., based on the second capacity retention rate corresponding to the second resistance. This reduces the computational load in the cycle life prediction process and improves the efficiency of the cycle life prediction process. It is applicable to the prediction of the cycle life of batteries whose bottom plate side electrode assembly is prone to failure.

[0189] In this application, the remaining usable cycle life of the battery is determined based on the first internal resistance and / or the second internal resistance, which can solve the problem of delayed early failure warning caused by existing methods that estimate lifespan from an overall perspective. Furthermore, it significantly improves early warning capabilities, issuing warnings as soon as localized degradation begins in the battery, with a warning lead time of 50% to 70% of the total cycle life.

[0190] Meanwhile, this application takes a local perspective, viewing battery aging as a physical process where "a local area fails first, gradually expanding to the whole," which is more in line with the physical nature of electrochemical aging compared to the traditional model that treats the battery as a homogeneous body. By capturing the resistance of local aging areas, it can accurately predict the time point when aging progresses from local to overall, resulting in smaller remaining lifespan prediction errors and significantly improved early warning accuracy.

[0191] It should be noted that the method in this embodiment can be executed by a single device, such as a computer or server. The method can also be applied in a distributed scenario, where multiple devices cooperate to complete the task. In such a distributed scenario, one of these devices may execute only one or more steps of the method in this embodiment, and the multiple devices will interact with each other to complete the method described.

[0192] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0193] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application is limited to these examples; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0194] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: The housing includes an open end and a closed end, and a signal acquisition unit is provided inside the closed end; A cover plate covers the opening end and, together with the housing, forms an accommodating space. The pole is insulated and connected to the cover plate; A connector is located inside the housing, and the connector includes a first connecting portion and a second connecting portion; An electrode assembly is disposed within the receiving space. The electrode assembly includes at least one main body, with a collection tab and a power tab respectively extending from opposite ends of the main body. The power tab is electrically connected to the first connecting part, the first connecting part is electrically connected to the electrode post, the collection tab is electrically connected to the second connecting part, and the second connecting part is electrically connected to the signal acquisition part. The signal acquisition part is used to collect the electrical signal of the electrode assembly and send the electrical signal to the battery management unit.

2. The battery cell according to claim 1, characterized in that, The main body includes two oppositely arranged sides, and the battery cell includes two oppositely arranged connectors. Each connector contacts one of the sides, and the second connection portion of each connector is located on the same side of the main body. The signal acquisition unit is connected to the second connection portions of both connectors, and the signal acquisition unit is used to acquire the electrical signal between the two second connection portions.

3. The battery cell according to claim 1, characterized in that, It also includes a data acquisition circuit board and a sealing terminal. The data acquisition circuit board is located on the side of the sealed end away from the main body. The signal acquisition part includes a first connection area and a second connection area. The first connection area is connected to the second connection area, and the second connection area is electrically connected to the data acquisition circuit board through the sealing terminal.

4. The battery cell according to claim 1, characterized in that, It also includes a data acquisition circuit board, which is located on the side of the closed end near the main body. The signal acquisition part includes a first connection area and a second connection area. The first connection area is connected to the second connection area, and the second connection area is electrically connected to the data acquisition circuit board.

5. The battery cell according to claim 4, characterized in that, The battery cell also includes at least one temperature sensor, which is located at one end of the main body near the signal acquisition unit and is electrically connected to the acquisition circuit board.

6. The battery cell according to claim 3 or 4, characterized in that, The signal acquisition unit further includes a signal bending region located between the first connection region and the second connection region. The battery cell further includes an acquisition bracket located inside the housing and covering the signal bending region.

7. The battery cell according to claim 6, characterized in that, The surface of the acquisition bracket near the closed end is the acquisition surface, and the surface of the second connection area near the closed end is the connection surface. The acquisition surface is flush with the connection surface, or the acquisition surface is located on the side of the connection surface away from the closed end.

8. The battery cell according to claim 7, characterized in that, The connector further includes a busbar connection portion, and the connector further includes a first bending portion and a second bending portion. The busbar connection portion is bendably connected to the first connection portion through the first bending portion, and is bendably connected to the second connection portion through the second bending portion. The battery cell also includes a bending bracket, which is disposed on the surface of the cover plate facing the main body or the surface of the closed end facing the main body. The bending bracket covers the first bending portion and the second bending portion, and the bending bracket abuts against the end face of the main body.

9. The battery cell according to claim 8, characterized in that, The bent support located between the main body and the closed end is the base support, the surface of the base support near the closed end is the base frame surface, the collection surface and the connecting surface are flush with the base frame surface, or the collection surface and the connecting surface are located on the side of the base frame surface away from the closed end; And / or, the orthographic projection of the acquisition circuit board on the first plane does not coincide with the orthographic projection of the base surface on the first plane, where the first plane is the plane containing the end face of the main body near the closed end.

10. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1 to 9.

Images