Battery cell connection system, power battery and heating method of power battery

Abstract

The invention discloses a battery cell connection system, a power battery and a heating method thereof, the battery cell connection system comprises: a battery cell connection assembly which is located at the top of a battery cell cover plate and comprises an electrical isolation plate, and a busbar and a sampling circuit which are located above the electrical isolation plate, the sampling circuit is electrically connected with a battery management system, and the sampling circuit is electrically connected with the battery management system; the temperature acquisition module is used for acquiring the temperature of each battery cell through the battery cell cover plate and sending the acquired temperature to the battery management system; the heating assembly comprises a heating circuit and a heating piece electrically connected with the heating circuit, and the heating piece is located between the battery cell cover plate and the electrical isolation plate and used for heating the battery cell through the battery cell cover plate when the heating circuit is disconnected and stopping heating when the heating circuit is disconnected. The heating element is integrally arranged in the battery cell connecting system, and the heating element is positioned on one side, in contact with the battery cell cover plate, of the battery cell connecting system, so that the battery cells can be efficiently and uniformly heated, and the cost is reduced on the premise of ensuring the structural strength and safety of the battery pack.

Description

Technical Field

[0001] This invention relates to the field of power battery thermal management technology, and in particular to a cell connection system, a power battery and a heating method thereof. Background Technology

[0002] Power batteries are the core energy storage components of new energy vehicles, and their low-temperature charging and discharging performance directly affects the reliability of the equipment. Therefore, existing battery packs are generally equipped with heating components to heat the cells to a suitable operating temperature at low temperatures, ensuring charging and discharging efficiency and lifespan. Traditional heating components are mostly located at the bottom or side of the battery. However, attaching them to the bottom of the cells reduces the structural adhesive bonding strength between the cells and the bottom liquid cooling plate, deteriorating the structural strength of the battery pack; attaching them to the side can easily cause the heating film to dry-burn due to air bubbles, posing a safety hazard.

[0003] To address the aforementioned issues, related technologies propose a solution where the heating element is positioned above the busbar on top of the battery cell. The busbar enables series-parallel connection of multiple cells and energy convergence. Heat is sequentially transferred to the battery cell's interior via the busbar, tabs, copper and aluminum foil, positive and negative electrode materials, separator, and electrolyte. Temperature in the busbar area is collected by sensors to control the heating film's operation. However, this solution has significant drawbacks: Firstly, the busbar's heat transfer area is limited, resulting in a long and multi-layered heat transfer path, low heating efficiency, and uneven temperature distribution. The tabs, in particular, have a very small cross-sectional area, acting as a bottleneck for heat transfer. Heat cannot penetrate quickly and evenly to the battery cell's winding area, easily causing temperature stratification within the cell and resulting in situations where the busbar temperature is significantly higher than the winding temperature. At this time, the temperature sensor collects the temperature of the busbar, which deviates greatly from the actual temperature of the battery cell winding. This causes the battery management system to make incorrect temperature control decisions, which in turn leads to the risk of low-temperature lithium plating in the battery cell, affecting battery life and safety. On the other hand, this solution also requires the addition of a cover plate to press the heating element to fit it in close with the busbar, so as to avoid gaps affecting heat transfer or causing overheating, which increases the types of materials, assembly processes and costs.

[0004] Therefore, how to achieve efficient and uniform heating of battery cells while reducing costs, while ensuring the structural strength and safety of the battery pack, is a technical problem that urgently needs to be solved in the field of power batteries. Summary of the Invention

[0005] In view of the above problems, the present invention provides a cell connection system, a power battery and a heating method thereof. By integrating the heating element into the cell connection system and placing the heating element on the side of the cell connection system that contacts the cell cover, efficient and uniform heating of the cell can be achieved and costs can be reduced while ensuring the structural strength and safety of the battery pack.

[0006] In a first aspect, a cell connection system is provided, comprising: A cell connection assembly, located on top of a cell cover, includes an electrical isolation plate, a busbar and a sampling circuit located above the electrical isolation plate. The sampling circuit is electrically connected to a battery management system and is used to collect the temperature of each cell through the cell cover and send the collected temperature to the battery management system. The heating assembly includes a heating circuit and a heating element electrically connected to the heating circuit. The heating element is located between the cell cover and the electrical isolation plate and is used to heat the cell through the cell cover when the heating circuit is disconnected and to stop heating when the heating circuit is disconnected. The heating circuit is electrically connected to the battery management system through the battery power distribution unit.

[0007] In some embodiments, the cell cover includes a cell electrode post protruding from the top of the cell cover; the heating element covers the top of the cell cover except for the area where the cell electrode post is located.

[0008] In some embodiments, the heating assembly further includes a heat-conducting element located between the heating element and the cell cover.

[0009] In some embodiments, the orthographic projection area of ​​the heat-conducting element on the top surface of the cell cover plate coincides with the orthographic projection area of ​​the heating element on the top surface of the cell cover plate.

[0010] In some embodiments, the cell connection assembly includes a plurality of busbars, and the electrical isolation plate is provided with a plurality of connecting areas for electrically connecting the busbars to the cell terminals on the top of the cell cover plate, wherein the plurality of connecting areas correspond one-to-one with the plurality of busbars; The sampling circuit is electrically connected to the plurality of busbars and is used to collect the voltage of the corresponding battery cell through the plurality of busbars and send the collected voltage to the battery management system.

[0011] In some embodiments, the sampling circuit includes a plurality of temperature sensors, a flexible circuit board, and a plurality of thermal pads, wherein the plurality of temperature sensors are electrically connected to the flexible circuit board, and the flexible circuit board is electrically connected to the battery management system. The top of the cell cover includes multiple temperature acquisition areas corresponding to multiple cells. Multiple temperature sensors are set in a one-to-one correspondence with the multiple temperature acquisition areas. Each temperature sensor is attached to the corresponding temperature acquisition area through the thermal pad so as to sense the temperature of the corresponding temperature acquisition area through the thermal pad and obtain the temperature of the cell corresponding to the temperature acquisition area.

[0012] In a second aspect, a power battery is provided, including a cell connection system, a cell module, a battery management system, and a battery power distribution unit as described in the first aspect.

[0013] Thirdly, a heating method for a power battery is provided, applicable to the power battery as described in the second aspect, the method comprising: Obtain the temperature of each cell in the battery module; The initial average temperature, initial maximum temperature, and initial minimum temperature of each cell are determined based on the temperature of each cell. Based on the pre-calibrated mapping relationship between the average temperature of the battery cell and the temperature difference of the battery cell, the temperature difference of the battery cell corresponding to the initial average temperature is determined as the target temperature difference. Based on the target temperature difference, the initial average temperature, the initial maximum temperature, and the initial minimum temperature, the target average temperature, the target maximum temperature, and the target minimum temperature are determined. Based on the target average temperature, target maximum temperature, and target minimum temperature, corresponding control commands are sent to the battery power distribution unit. The control commands are used to instruct the battery power distribution unit to control the heating circuit to close or open, so that the heating element heats or stops heating the battery cell.

[0014] In some embodiments, determining the target average temperature, target maximum temperature, and target minimum temperature based on the target temperature difference, the initial average temperature, the initial maximum temperature, and the initial minimum temperature includes: The target average temperature is determined based on the target temperature difference and the initial average temperature; The target maximum temperature is determined based on the target temperature difference and the initial maximum temperature; The target minimum temperature is determined based on the target temperature difference and the initial minimum temperature.

[0015] In some embodiments, based on the target average temperature, target maximum temperature, and target minimum temperature, corresponding control commands are sent to the battery power distribution unit, including: If the difference between the target maximum temperature and the target minimum temperature is less than or equal to a preset difference threshold, and the target minimum temperature is less than or equal to a preset first cell temperature, and the target average temperature is less than or equal to a preset first average temperature threshold, a first control command is sent to the battery power distribution unit. The first control command is used to instruct the battery power distribution unit to control the heating circuit to close, so that the heating element heats the battery cell. If the difference between the target maximum temperature and the target minimum temperature is less than or equal to the difference threshold, and the target maximum temperature is greater than or equal to the preset second cell temperature, and the target average temperature is greater than or equal to the preset second average temperature threshold, a second control command is sent to the battery power distribution unit. The second control command is used to instruct the battery power distribution unit to control the heating circuit to disconnect, so that the heating element stops heating the battery cell. If the difference between the target maximum temperature and the target minimum temperature is greater than the difference threshold, the second control command is sent to the battery power distribution unit.

[0016] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: By placing the heating element between the cell cover and the electrical isolation plate, and positioning the sampling circuit above the electrical isolation plate to directly collect the temperature of each cell through the cell cover, this design avoids the safety hazards of traditional heating elements that are attached to the bottom of the cell, reducing the structural strength of the battery pack, or attached to the side, which can easily cause dry burning. It also eliminates the need for an additional cover to press the heating element, reducing the types of materials and assembly processes, effectively lowering production costs. Furthermore, the heat generated by the heating element can be directly transferred to the inside of the cell through the cell cover, significantly shortening the heat transfer path and avoiding heat transfer bottlenecks such as busbars and tabs. This achieves efficient and uniform heating of the cell. The temperature of the cell cover collected by the sampling circuit is closer to the actual temperature of the cell core, providing accurate temperature control data for the battery management system. This avoids erroneous temperature control decisions caused by temperature acquisition deviations and the risk of low-temperature lithium plating in the cell, ensuring battery charging and discharging efficiency and lifespan.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of a battery cell connection system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of another battery cell connection system provided in an embodiment of the present invention; Figure 3 This is a flowchart of a heating method provided in an embodiment of the present invention; Figure 4 This is a flowchart of another heating method provided in an embodiment of the present invention; Figure 5 This is a structural block diagram of a heating device provided in an embodiment of the present invention. Detailed Implementation

[0019] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to the accompanying drawings and specific implementation methods. It should be understood that the embodiments of this disclosure and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. Unless otherwise specified, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0020] Figure 1 This is a schematic diagram of a cell connection system provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the cell connection system 100 includes a cell connection assembly 110 and a heating assembly 120.

[0021] The cell connection assembly 110 is located on top of the cell cover 210 of the cell module 200, and includes an electrical isolation plate 111, a bus 112 and a sampling circuit 113 located above the electrical isolation plate 111. The sampling circuit 113 is electrically connected to the battery management system (not shown in the figure) and is used to collect the temperature of each cell through the cell cover 210 and send the collected temperature to the battery management system.

[0022] The heating assembly 120 includes a heating circuit (not shown) and a heating element 121 electrically connected to the heating circuit. The heating element 121 is located between the cell cover 210 and the electrical isolation plate 111, and is used to heat the cell through the cell cover 210 when the heating circuit is disconnected, and to stop heating when the heating circuit is disconnected. The heating circuit is electrically connected to the battery management system through the battery power distribution unit.

[0023] The battery module 200 includes multiple battery cells 220 and a battery cell cover plate located on top of the battery cells 220. The battery cell cover plate 210 is a structural component of the battery cell 220, used to encapsulate the battery cell housing and support the battery cell terminals, while also serving as the heat transfer medium for the heating element 121 and the temperature acquisition carrier for the sampling circuit 113. The electrical isolation plate 111 is used to achieve electrical isolation between the bus 112, the sampling circuit 113 and the heating element 120, preventing short circuits between the bus and the sampling circuit and the heating element, while also providing support and fixation for the bus 112 and the sampling circuit 113, ensuring the structural stability of the battery cell connection assembly. The bus 112 is used to realize the series and parallel electrical connection between the multiple battery cells 220 in the battery module 200, undertaking the function of power transmission between the battery cells. Its layout path matches the series and parallel topology of the battery cells, ensuring the reliability of the current conduction of the battery module. The heating circuit is used to close under the control of the battery distribution unit to heat the heating element, or to open under the control of the battery distribution unit to stop the heating element from heating. The battery distribution unit controls the opening and closing of the heating circuit based on control commands sent by the battery management system.

[0024] Compared to related technologies that place the heating element above the busbar at the top of the cell, the heat conduction path is as long as nine layers: heater - busbar - tab - copper and aluminum foil - positive and negative electrode materials - separator - electrolyte - aluminum-plastic film - external components of the cell. Moreover, the small cross-sectional area of ​​the tab becomes a bottleneck for heat transfer, resulting in obstructed heat transfer. In this application, the heating element 121 is located between the cell cover 210 and the electrical isolation plate 111. The heat conduction path is heating element - cell cover (cell shell) - electrolyte, requiring only three levels and no additional redundant transmission links. This completely avoids the heat transfer bottleneck of the tabs. Therefore, the heat transfer in this application is more direct and efficient, and can quickly and evenly penetrate to the cell winding area, avoiding temperature stratification inside the cell. At the same time, the sampling circuit 113 directly collects the temperature of the cell cover 210, which is closer to the actual temperature of the cell winding. This avoids the temperature control deviation caused by collecting busbar temperature in the prior art, greatly reducing the risk of low-temperature lithium plating in the cell and ensuring battery life and safety. In addition, this application does not require an additional cover to press the heating element, and also avoids the problems of the heating element being attached to the bottom surface reducing the structural strength of the battery pack and being attached to the side easily causing dry burning. This reduces the types of materials and assembly processes, effectively reducing production costs.

[0025] Figure 2 This is a schematic diagram of another cell connection system provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the cell cover 210 includes a cell electrode post 211 protruding from the top of the cell cover 210. The heating element 121 covers the top area of ​​the cell cover excluding the area where the cell electrode post is located.

[0026] The core function of the cell cover 210 is to seal the top opening of the cell housing, achieving internal sealing and preventing electrolyte leakage. It also provides a mounting base for components such as the terminals and explosion-proof valves, ensuring the structural integrity and safety of the cell. As a good thermal conductor made of metal, it can also receive heat transferred from the heating element 121 and conduct it evenly to the inside of the cell. Simultaneously, it provides a carrier close to the cell core for temperature acquisition by the sampling circuit 113, ensuring the accuracy of temperature acquisition. The core function of the cell terminals 211 is to act as a conductive bridge between the internal electrodes (positive / negative) and the external circuit. One end extends into the cell and connects to the tab / plate, while the other end is exposed on the outside of the cell cover for welding to the busbar 112 of the cell connection system. This enables series and parallel connection of multiple cells and power output / input, ensuring the reliability of current conduction in the cell module 200.

[0027] For example, the heating element 121 includes a heating film layer located between the cell cover plate 210 and the electrical isolation plate 111. The heating film layer can be one of PI (Polyimide) heating film, silicone heating film, or PET (Polyethylene Terephthalate) heating film. The heating element 121 covers the top area of ​​the cell cover plate 210 except for the area where the cell electrode post 211 is located. That is, the orthogonal projection area of ​​the heating element 121 on the top surface of the cell cover plate 210 does not overlap with the area where the cell electrode post 211 is located, and completely avoids the welding area of ​​the busbar 112 and its projection area below the electrical isolation plate 111, so as to avoid the heating film affecting the welding of the busbar 112 and the cell electrode post 211, while maximizing the contact area between the heating element 121 and the cell cover plate 210 and improving the heating uniformity.

[0028] In some embodiments, such as Figure 2 As shown, the heating assembly 120 also includes a heat-conducting element 122, which is located between the heating element 121 and the cell cover plate 210.

[0029] For example, the heat-conducting component 122 is a silicone thermal pad or thermal gel. The heat-conducting component 122 can completely fill the gap between the heating component 121 and the cell cover plate 210, eliminating the heat transfer resistance caused by air in the gap. At the same time, by utilizing the excellent thermal conductivity of the silicone thermal pad or thermal gel, the heat generated by the heating component 121 is quickly and evenly transferred to the cell cover plate 210, further shortening the thermal resistance loss of the heat transfer path. In addition, the heat-conducting component can also adapt to the small dimensional deviations between the heating component 121 and the cell cover plate 210, achieving a tight fit between the two, ensuring the stability and reliability of heat transfer. Combined with the large-area coverage design of the heating component 121 over the cell cover plate 210, it further improves the overall heating uniformity of the cell and avoids problems such as excessively high local temperatures or insufficient heating.

[0030] In some embodiments, the projected area of ​​the heat-conducting element 122 on the top surface of the cell cover 210 coincides with the projected area of ​​the heating element 121 on the top surface of the cell cover 210. On the one hand, this ensures that the heat-conducting element 122 completely covers the heating area of ​​the heating element 121, so that all the heat generated by the heating element 121 is transferred to the cell cover 210 through the heat-conducting element 122, preventing heat loss from the uncovered edges of the heating element 121 and maximizing heat utilization. On the other hand, in conjunction with the design of the heating element 121 avoiding the projection areas of the cell terminals and busbars, it can achieve a precise correspondence between the heat conduction path and the heating area without affecting the welding of the busbars and terminals, ensuring that heat is evenly transferred to the cell cover 210, thereby making the internal temperature distribution of the cell more balanced, avoiding local insufficient heating or heat accumulation, further improving heating efficiency and temperature control accuracy, while adapting to the requirements of integrated structural design without adding extra assembly complexity.

[0031] In some embodiments, the cell connection assembly 110 includes a plurality of busbars 112, and the electrical isolation plate 111 has a plurality of connected areas for electrically connecting the busbars 112 to the cell terminals 211 on the top of the cell cover plate 210, wherein the plurality of connected areas correspond one-to-one with the plurality of busbars 112. The sampling circuit 113 is electrically connected to the plurality of busbars 112 and is used to collect the voltage of the corresponding cell through the plurality of busbars 112 and send the collected voltage to the battery management system.

[0032] In other words, the sampling circuit 113 has a voltage acquisition function and can acquire the voltage of each cell through the bus 112. Since the multiple cells 220 within the cell module 200 need to be connected in series and parallel topologies according to the voltage and capacity requirements of the power battery, different connection relationships require precise conductive connections between the cell terminals through independent busbars. Therefore, multiple busbars are needed to adapt to the series and parallel layout of multiple cells, ensuring that each cell terminal can reliably connect to the corresponding busbar, thus guaranteeing the stability of power transmission. The sampling circuit 113 includes sampling cables (which can be wire harnesses, flexible circuit boards, or flexible flat wire harnesses, etc.), nickel sheets, etc. When multiple cells are connected in series, multiple busbars respectively connect to the positive and negative terminals of adjacent cells, forming a series conductive connection. The circuit uses a sampling cable that is electrically connected to each busbar via a nickel strip. The conductivity of the nickel strip is used to collect the potential signal at each busbar, and the individual cell voltage is calculated by converting the potential difference. When multiple cells are connected in parallel, multiple busbars are connected to the same polarity of the cell terminals (all positive terminals or all negative terminals), achieving current convergence across multiple cells. The sampling cable collects the potential signal of each busbar via the nickel strip. Since the parallel cells have the same potential, the accuracy of the voltage signal can be verified through multiple sets of collected data. Simultaneously, the voltage stability of the parallel circuit is monitored in real time, ensuring that the voltage state of each cell can be accurately sensed.

[0033] For example, bus 112 can be a copper-aluminum bus (a general term for copper or aluminum bus, which has excellent conductivity and can reliably carry large current transmission between battery cells); electrical isolation plate 111 is usually a plastic sheet or film, and the material is usually PC (Polycarbonate), PP (Polypropylene), PET (Polyethylene Terephthalate), etc. These materials have good insulation, mechanical strength and temperature resistance, and can effectively isolate the high-voltage bus from the low-voltage sampling circuit and heating components, while meeting the integrated fixing requirements of the battery cell connection system. For products where the electrical isolation plate 111 is made of plastic sheet, the busbar 112, sampling line (sampling circuit 113), heating element 121, heat-conducting element 122, and electrical isolation plate 111 can be fixed together by hot riveting process. The mechanical connection characteristics of hot riveting are used to achieve tight assembly of each component and ensure structural stability. For products where the electrical isolation plate 111 is made of PET film, the busbar 112, sampling line (sampling circuit 113), heating element 121, heat-conducting element 122, and electrical isolation plate 111 can be fixed together by hot pressing or cold pressing process. The synergistic effect of pressure and temperature is used to achieve bonding and fixation of each layer structure.

[0034] In some embodiments, the sampling circuit 113 includes multiple temperature sensors, a flexible circuit board, and multiple thermal pads. The multiple temperature sensors are electrically connected to the flexible circuit board, and the flexible circuit board is electrically connected to the battery management system. The top of the cell cover includes multiple temperature acquisition areas corresponding to multiple cells. Multiple temperature sensors are arranged corresponding to multiple temperature acquisition areas. Each temperature sensor is attached to the corresponding temperature acquisition area through a thermal pad to sense the temperature of the corresponding temperature acquisition area and obtain the temperature of the cell corresponding to the temperature acquisition area.

[0035] By setting up multiple temperature sensors corresponding to each battery cell and using thermal pads to ensure a tight fit between each sensor and the corresponding temperature acquisition area on the cell cover, the system can quickly transfer heat from the temperature acquisition area through the thermal pads. This allows the temperature sensors to accurately perceive the true temperature of each cell, avoiding temperature deviations caused by single-sensor acquisition and ensuring that the battery management system obtains independent temperature data for each cell. On the other hand, the integrated connection design of the flexible circuit board ensures the stability and reliability of temperature signal transmission and adapts to the integrated layout of the cell connection system. Combined with the heating function of the heating components, this provides the battery management system with accurate data on cell temperature. Furthermore, the heating components enable precise temperature control of each cell, effectively avoiding the risks of low-temperature lithium plating and excessive temperature differences, further ensuring the safety and lifespan of the battery system.

[0036] It should be noted that, Figure 1 and Figure 2 The hierarchical relationship between the electrical isolation plate 111, bus 112, and sampling circuit 113 in the cell connection assembly 110 is only an example. In practice, the bus 112 and sampling circuit can be located on the same layer, or can be flexibly adjusted according to the distribution of cell terminals and signal acquisition path requirements. For example, the flexible circuit board of the sampling circuit 113 can be arranged side by side with the bus 112 above the electrical isolation plate 111, and a precise electrical connection with the bus can be achieved through a nickel strip; or part of the sampling circuit structure (such as the temperature sensor connection harness) can be laid on the surface of the electrical isolation plate 111, only maintaining electrical insulation from the bus. The core design principle is to ensure that the bus 112 can be reliably welded to the cell terminals through the connected area of ​​the electrical isolation plate 111, that the sampling circuit 113 can stably acquire voltage and temperature signals, and that it does not interfere with the heat transfer path of the heating film layer and the heat conductor, and that all components meet the electrical insulation requirements, adapting to the design requirements of integrated and miniaturized power batteries.

[0037] This invention integrates the heating function into a cell connection system with electrical connection and signal acquisition capabilities. It utilizes the existing Cell Connection System (CCS) installation layout located above the cell top cover, eliminating the need for additional space for heating components. It also reuses the existing mounting bases for core components such as busbars, sampling lines, and electrical isolation boards, eliminating the need for additional module cover plates or other clamping structures. This significantly reduces the types of materials and assembly processes required for power batteries, lowering material management and process costs. Furthermore, leveraging the integrated advantages of existing sampling circuits, it simultaneously achieves accurate acquisition of cell voltage and temperature signals, providing reliable data support for heating control. Combined with a short-path heat transfer design from the heating component to the cell cover and electrolyte, it avoids the structural strength degradation and dry-burning risks associated with traditional heating film mounting on the bottom / side surfaces. It also solves the problems of multiple heat transfer layers, tab heat transfer bottlenecks, and large temperature sensing deviations in existing technologies. While ensuring battery safety and structural stability, it significantly improves low-temperature heating efficiency and temperature control accuracy.

[0038] Based on the same inventive concept, embodiments of the present invention also provide a power battery, including a cell connection system, a cell module, a battery management system, and a battery power distribution unit as described in the above embodiments.

[0039] The battery module includes multiple battery cells and a battery cell cover. The battery cells are arranged in an array, and the battery cell cover is encapsulated on top of the multiple battery cells. The battery cell cover has a battery cell terminal corresponding to each battery cell, which protrudes from the top surface of the battery cell cover and is used to form a reliable electrical connection with the bus in the battery cell connection system. The bus is welded to the battery cell terminal through the connecting area of ​​the electrical isolation plate to realize the series and parallel electrical connection of multiple battery cells. The sampling circuit is electrically connected to the bus through a nickel strip and collects voltage and temperature signals through a temperature sensor attached to the battery cell cover. The heating element is tightly attached to the battery cell cover through a thermal pad / thermal conductive gel, and the heating element is set to avoid the welding area between the bus and the terminal to avoid affecting the welding reliability.

[0040] The battery management system is electrically connected to the battery power distribution unit and the sampling circuit. Based on the cell temperature collected by the sampling circuit, the battery power distribution unit controls the on / off state of the heating circuit, thereby controlling the heating element to heat or stop heating. Heat is transferred to the cell through the cell cover plate to achieve heating or stopping the heating of the cell.

[0041] Based on the same inventive concept, this invention also provides a heating method for a power battery, applicable to the power battery described in the above embodiments. The subject executing the heating method can be a battery management system (BMS). Figure 3 This is a flowchart of a heating method provided in an embodiment of the present invention, such as... Figure 3 As shown, the heating method includes: Step S310: Obtain the temperature of each cell in the battery module.

[0042] In some embodiments, the temperature of each cell collected by the sampling circuit 130 can be obtained. Specifically, the temperature data (i.e., T1, T2, T3, ..., Tn, where n is the number of cells) sensed by the temperature sensor in the sampling circuit 130 corresponding to each cell through the temperature acquisition area of ​​the cell cover plate with the thermal pad is transmitted to the BMS via the flexible circuit board to ensure that the BMS obtains the independent temperature information of each cell.

[0043] Step S320: Determine the initial average temperature, initial maximum temperature, and initial minimum temperature of each cell based on the temperature of each cell.

[0044] In some embodiments, based on the collected temperatures of multiple battery cells, an initial maximum temperature Tmax can be selected, an initial minimum temperature Tmin can be selected, and then the average temperature of the multiple battery cells can be calculated as the initial average temperature Tavg. The average temperature Tavg of the multiple battery cells can be calculated using the following formula: Tavg=(T1+T2+T3+…+Tn) / n; Where n is the total number of cells in the cell module whose temperature is collected, and T1 to Tn are the collected temperatures of each cell.

[0045] Step S330: Based on the pre-calibrated mapping relationship between the average temperature of the battery cell and the temperature difference of the battery cell, determine the temperature difference of the battery cell corresponding to the initial average temperature as the target temperature difference.

[0046] In some embodiments, the mapping relationship can be established through experimental calibration. Specifically, within the full temperature operating range of the power battery (e.g., -30℃ to 60℃), multiple temperature nodes are selected. At each node, the power battery is placed in a static state. The temperature of each cell is collected through a sampling circuit, and the initial average temperature Tavg is calculated. At the same time, a high-precision built-in sensor is used to directly measure the true average temperature of the cell winding core. The difference ΔT between the true average temperature of the winding core at each temperature node and the collected initial average temperature is calculated. The initial average temperature of each temperature node is mapped one-to-one with the corresponding ΔT to form a preset mapping relationship table or fitting function, which is stored in the BMS for real-time query and retrieval.

[0047] Step S340: Based on the target temperature difference, initial average temperature, initial maximum temperature, and initial minimum temperature, determine the target average temperature, target maximum temperature, and target minimum temperature.

[0048] In some embodiments, step S340 includes: The target average temperature Tavg is determined based on the target temperature difference ΔT and the initial average temperature Tavg; where the target average temperature Tavg' is equal to the sum of the target temperature difference ΔT and the initial average temperature Tavg, i.e., Tavg' = ΔT + Tavg.

[0049] Based on the target temperature difference ΔT and the initial maximum temperature Tmax, the target maximum temperature Tmax' is determined; where the target maximum temperature Tmax' is equal to the sum of the target temperature difference ΔT and the initial maximum temperature Tmax, that is, Tmax'=ΔT+Tmax.

[0050] Based on the target temperature difference ΔT and the initial minimum temperature Tmin, the target minimum temperature Tmin' is determined; where the target minimum temperature Tmin' is equal to the sum of the target temperature difference ΔT and the initial minimum temperature Tmin, that is, Tmin' = ΔT + Tmin.

[0051] By correcting the initial average temperature Tavg, initial maximum temperature Tmax, and initial minimum temperature Tmin using the target temperature difference ΔT, the calculated target temperatures Tavg', Tmax', and Tmin' can be made closer to the actual temperature of the battery cell core. This avoids deviations from the actual core temperature caused by the temperature sensor collecting the temperature of the battery cell cover plate, thus solving the problem of temperature control decision errors caused by inaccurate temperature sensing in existing technologies.

[0052] Step S350: Based on the target average temperature, target maximum temperature and target minimum temperature, send corresponding control commands to the battery power distribution unit. The control commands are used to instruct the battery power distribution unit to control the heating circuit to close or open, so that the heating element heats or stops heating the battery cell.

[0053] In some embodiments, step S350 includes: If the difference between the target maximum temperature Tmax' and the target minimum temperature Tmin' is less than or equal to the preset difference threshold T0, and the target minimum temperature Tmin' is less than or equal to the preset first cell temperature T01, and the target average temperature Tavg' is less than or equal to the preset first average temperature threshold Tavg1', a first control command is sent to the battery power distribution unit. The first control command is used to instruct the battery power distribution unit to control the heating circuit to close, so that the heating element heats the battery cell. If the difference between the target maximum temperature Tmax' and the target minimum temperature Tmin' is less than or equal to the difference threshold T0, and the target maximum temperature Tmax' is greater than or equal to the preset second cell temperature T02, and the target average temperature Tavg' is greater than or equal to the preset second average temperature threshold Tavg2', a second control command is sent to the battery power distribution unit. The second control command is used to instruct the battery power distribution unit to control the heating circuit to disconnect, so that the heating element stops heating the battery cell. If the difference between the target maximum temperature Tmax' and the target minimum temperature Tmin' is greater than the difference threshold T0, a second control command is sent to the battery power distribution unit to stop the heating element from heating the battery cells, and a fault command containing the target fault code is sent to the vehicle controller. The target fault code is used to indicate that the temperature difference of the battery cells is too large.

[0054] Figure 4 This is a flowchart of another heating method provided in an embodiment of the present invention, such as... Figure 4 As shown, exemplarily in this heating method: If Tmax'-Tmin'≤20℃ (at this time T0=20℃), and Tmin'≤5℃ (at this time T01=5℃), and Tavg'≤5℃ (at this time Tavg1'=5℃), the BMS sends the first control command (heating and heat preservation command) to the battery power distribution unit to close the heating circuit, and the heating film is in the heating state.

[0055] If Tmax'-Tmin'≤20℃ (at this time T0=20℃), and Tmax'≥55℃ (at this time T02=55℃), and Tavg'≥45℃ (at this time Tavg2'=45℃), the BMS sends a second control command (cooling command) to the battery power distribution unit to disconnect the heating circuit, and the heating film stops heating.

[0056] If Tmax'-Tmin'>20℃ (at this time T0=20℃), the BMS sends a second control command (cooling command) to the battery power distribution unit to disconnect the heating circuit, and the heating film stops heating; at the same time, the BMS sends a fault command containing the target fault code to the vehicle controller.

[0057] Upon receiving a fault command, the vehicle controller immediately triggers the battery's safety protection strategy. Based on the fault level, it limits the battery's output power and switches the vehicle's driving mode to limp mode. In this mode, the vehicle can only travel at low speeds (e.g., no more than 20 km / h) to prevent localized thermal runaway or severe performance degradation due to excessive cell temperature differences. Simultaneously, the vehicle controller sends an alarm signal to the dashboard, illuminating a turtle-shaped limp mode indicator light. This visually alerts the driver that the vehicle has a fault with excessive cell temperature differences and requires immediate pullover and repair. This ensures driving safety and prevents further irreversible damage to the battery.

[0058] The above heating method collects temperature data of all cells through BMS, calculates the average temperature and the highest / lowest temperature, and converts the actual temperature of the cell core into the calibration dataset. Then, it controls the heating element to start or stop or report faults according to the temperature threshold, so as to accurately control the cell within a reasonable operating temperature range, effectively reduce the risk of low-temperature lithium plating, and ensure battery safety and life. It is suitable for power batteries and electric vehicles equipped with this battery.

[0059] Based on the same inventive concept, embodiments of the present invention also provide a heating device for implementing the above-described heating method. Figure 5 This is a structural block diagram of a heating device provided in an embodiment of the present invention, such as... Figure 5 As shown, the device 500 includes: The acquisition module 510 is used to acquire the temperature of each cell in the battery module; The first determining module 520 is used to determine the initial average temperature, initial maximum temperature and initial minimum temperature of the battery cell based on the temperature of each battery cell. The second determining module 530 is used to determine the cell temperature difference corresponding to the initial average temperature as the target temperature difference value based on the pre-calibrated mapping relationship between the average temperature of the cell and the cell temperature difference. The third determining module 540 is used to determine the target average temperature, target maximum temperature and target minimum temperature based on the target temperature difference, initial average temperature, initial maximum temperature and initial minimum temperature; The control module 550 is used to send corresponding control commands to the battery power distribution unit based on the target average temperature, target maximum temperature and target minimum temperature. The control commands are used to instruct the battery power distribution unit to control the heating circuit to close or open, so that the heating element heats or stops heating the battery cell.

[0060] In some embodiments, the third determining module 540 is used to: The target average temperature is determined based on the target temperature difference and the initial average temperature. The target maximum temperature is determined based on the target temperature difference and the initial maximum temperature. The target minimum temperature is determined based on the target temperature difference and the initial minimum temperature.

[0061] In some embodiments, the third determining module 540 is used to: If the difference between the target maximum temperature and the target minimum temperature is less than or equal to a preset difference threshold, and the target minimum temperature is less than or equal to a preset first cell temperature, and the target average temperature is less than or equal to a preset first average temperature threshold, a first control command is sent to the battery distribution unit. The first control command is used to instruct the battery distribution unit to control the heating circuit to close so that the heating element heats the battery cell. If the difference between the target maximum temperature and the target minimum temperature is less than or equal to the difference threshold, and the target maximum temperature is greater than or equal to the preset second cell temperature, and the target average temperature is greater than or equal to the preset second average temperature threshold, a second control command is sent to the battery power distribution unit. The second control command is used to instruct the battery power distribution unit to control the heating circuit to disconnect, so that the heating element stops heating the battery cell. If the difference between the target maximum temperature and the target minimum temperature is greater than the difference threshold, a second control command is sent to the battery power distribution unit.

[0062] The specific details of the heating method used in the above heating device can be understood by referring to the relevant descriptions and effects in the above-described heating method embodiments, and will not be repeated here.

[0063] Based on the same inventive concept as the heating method described above, this invention also provides an electronic device, which may include a processor and a memory, wherein the processor and memory can communicate with each other via a bus or other means. The processor may be a Central Processing Unit (CPU). The processor may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations thereof. The memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the heating method in the embodiments of this invention. The processor executes various functional applications and data processing by running the non-transitory software programs, instructions, and modules stored in the memory, thereby implementing the heating method in the above method embodiments.

[0064] The memory may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created by the processor, etc. Furthermore, the memory may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. The one or more modules are stored in the memory and, when executed by the processor, perform actions such as... Figure 3 The heating method in the illustrated embodiment.

[0065] For specific details regarding the aforementioned electronic devices, please refer to the relevant documentation. Figure 3 The relevant descriptions and effects in the illustrated embodiments are for understanding purposes only and will not be repeated here.

[0066] Based on the same inventive concept as the heating method, the present invention also provides a computer-readable storage medium storing computer instructions, which are used to cause a computer to execute the heating method in the above embodiments.

[0067] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The storage medium can be read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0068] The technical solutions provided in the above embodiments of this application have at least the following technical effects or advantages: By placing the heating element between the cell cover and the electrical isolation plate, and positioning the sampling circuit above the electrical isolation plate to directly collect the temperature of each cell through the cell cover, this design avoids the safety hazards of traditional heating elements that are attached to the bottom of the cell, reducing the structural strength of the battery pack, or attached to the side, which can easily cause dry burning. It also eliminates the need for an additional cover to press the heating element, reducing the types of materials and assembly processes, effectively lowering production costs. Furthermore, the heat generated by the heating element can be directly transferred to the inside of the cell through the cell cover, significantly shortening the heat transfer path and avoiding heat transfer bottlenecks such as busbars and tabs. This achieves efficient and uniform heating of the cell. The temperature of the cell cover collected by the sampling circuit is closer to the actual temperature of the cell core, providing accurate temperature control data for the battery management system. This avoids erroneous temperature control decisions caused by temperature acquisition deviations and the risk of low-temperature lithium plating in the cell, ensuring battery charging and discharging efficiency and lifespan.

[0069] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0070] Similarly, it should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof. However, this method of disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0071] It should be noted that the above embodiments are illustrative of the invention and not restrictive of the invention, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims.

Claims

1. An electrical cell connection system, characterized by The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit.

2. The cell connection system of claim 1, wherein, The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit.

3. The cell connection system of claim 2, wherein, The application relates to a battery management system and a battery power distribution unit.

4. The cell connection system of claim 3, wherein, The application relates to a battery management system and a battery power distribution unit.

5. The cell connection system of claim 1, wherein, The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit.

6. The cell connection system of claim 1, wherein, The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit.

7. A power cell, characterized by The application relates to a battery management system and a battery power distribution unit.

8. A method of heating a power cell, characterized by, The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. The application relates to a battery management system and a battery power distribution unit. 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9. The heating method of claim 8, wherein, The target average temperature, the target maximum temperature and the target minimum temperature are determined based on the target temperature difference, the initial average temperature, the initial maximum temperature and the initial minimum temperature, and the determination includes: The target average temperature is determined based on the target temperature difference and the initial average temperature; The target maximum temperature is determined based on the target temperature difference and the initial maximum temperature; The target minimum temperature is determined based on the target temperature difference and the initial minimum temperature.

10. The heating method of claim 8, wherein, Based on the target average temperature, the target maximum temperature and the target minimum temperature, a corresponding control instruction is sent to a battery distribution unit, and the control instruction is used to instruct the battery distribution unit to control a heating circuit to be closed or opened, so that the heating member heats or stops heating the battery cell. If the difference between the target maximum temperature and the target minimum temperature is less than or equal to a preset difference threshold value, and the target minimum temperature is less than or equal to a preset first cell temperature, and the target average temperature is less than or equal to a preset first average temperature threshold value, a first control instruction is sent to the battery distribution unit, and the first control instruction is used to instruct the battery distribution unit to control the heating circuit to be closed, so that the heating member heats the battery cell; If the difference between the target maximum temperature and the target minimum temperature is less than or equal to the difference threshold value, and the target maximum temperature is greater than or equal to a preset second cell temperature, and the target average temperature is greater than or equal to a preset second average temperature threshold value, a second control instruction is sent to the battery distribution unit, and the second control instruction is used to instruct the battery distribution unit to control the heating circuit to be opened, so that the heating member stops heating the battery cell; If the difference between the target maximum temperature and the target minimum temperature is greater than the difference threshold value, the second control instruction is sent to the battery distribution unit.

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