A household battery pack heating system and a household battery pack device

Abstract

The embodiment of the specification discloses a household battery pack heating system and a household battery pack equipment, and the battery pack comprises a plurality of battery cells arranged in a rectangular array. The active temperature control device comprises a temperature sensor arranged on each battery cell, a plurality of heating units arranged on each side wall of the battery pack, and an active temperature control system. Each temperature sensor detects the temperature value of the corresponding battery cell. The active temperature control system obtains the temperature value of each battery cell output by each temperature sensor, and sets the heating power of each heating unit based on the temperature value of each battery cell and the relative position of each battery cell in the battery pack. Each heating unit heats the battery pack based on the corresponding heating power output by the active temperature control system. Through the active and uniform heating strategy, the battery working temperature is improved, thereby improving the ion diffusion and reaction rate, and fundamentally ensuring the charging safety and performance at low temperature.

Description

Technical Field

[0001] Several embodiments in this specification relate to the field of chemical battery heating technology, specifically to the optimization of uniformity in battery pack heating. Background Technology

[0002] Household batteries refer to lithium battery packs used in home energy storage scenarios. They are usually composed of multiple cells connected in series or parallel and need to operate safely in low-temperature environments.

[0003] In the current field of residential battery technology, lithium batteries face significant technical challenges in low-temperature environments. When ambient temperature decreases, the battery's internal resistance increases significantly, and its capacity drops rapidly. Especially during charging, lithium dendrites are easily formed. These dendrites can puncture the separator, causing internal short circuits and triggering thermal runaway, potentially leading to fires, explosions, and other safety accidents. In existing technologies, commercial and industrial energy storage batteries typically employ liquid-cooled temperature control systems for heating and cooling. However, due to cost and control complexity considerations, residential battery products often lack liquid-cooling systems and instead rely on external heating devices for heating.

[0004] The common solution currently is to add a heating device to the bottom of the battery to heat it to a suitable temperature before charging. This method has significant drawbacks: the heating time is relatively long, and due to the heat buildup effect, uneven temperatures often occur, with the center of the battery being higher and the sides lower. This temperature inconsistency severely affects the long-term reliability of the battery, leading to uneven performance degradation of individual cells within the battery pack and shortening the overall lifespan. This temperature inconsistency problem is particularly prominent in residential energy storage scenarios that require high reliability. Summary of the Invention

[0005] This specification provides a residential battery pack heating system and residential battery pack equipment. The core objective of this solution is to increase the battery operating temperature through an active and uniform heating strategy, thereby improving ion diffusion and reaction rate, fundamentally suppressing the above-mentioned problems, and ensuring charging safety and performance at low temperatures.

[0006] The technical solution is as follows:

[0007] An active temperature control device for a household battery pack, the battery pack comprising multiple cells arranged in a rectangular array, including a temperature sensor disposed on each cell, multiple heating units disposed on each side wall of the battery pack, and an active temperature control system;

[0008] Each of the temperature sensors detects the temperature value of its corresponding battery cell;

[0009] The active temperature control system acquires the temperature value of each corresponding cell output by each temperature sensor, and sets the heating power of each heating unit based on the temperature value of each cell and the relative position of each cell in the battery pack.

[0010] Each of the heating units heats the battery pack based on its corresponding heating power output by the active temperature control system.

[0011] As a preferred embodiment, the active temperature control system is set to a rapid heating mode in which each heating unit heats up at maximum power when there are battery cells with a temperature value lower than the safety threshold.

[0012] When the temperature of each cell is greater than the safety threshold and the maximum temperature difference between the cells is greater than the equalization threshold, the active temperature control system determines the nearest heating unit based on the relative position of the cell with the lowest temperature in the battery pack, and sets the nearest heating unit to a temperature equalization mode that heats up at maximum power.

[0013] When the temperature of each cell is greater than the safety threshold, the maximum temperature difference between each cell is less than the equilibrium threshold, and there are cells with temperatures lower than the ideal threshold, the active temperature control system obtains the adaptive heating power corresponding to each heating unit based on the temperature difference between each cell and the ideal threshold and the relative position of each cell in the battery pack, and sets it to a conventional heating mode in which each heating unit heats up with its corresponding adaptive heating power.

[0014] As a preferred embodiment, the active temperature control system obtains the adaptive heating power corresponding to each heating unit based on the temperature difference between each cell and the ideal threshold and the relative position of each cell in the battery pack, specifically as follows:

[0015] For any heating unit, the adaptive heating power is obtained based on the temperature difference between each cell from the central cell to the side of the battery pack where the heating unit is located and the ideal threshold, as well as the distance from the central cell.

[0016] As a preferred embodiment, the active temperature control system also obtains the adaptive heating power corresponding to each heating unit based on the temperature value of the central battery cell.

[0017] As a preferred embodiment, each heating unit is bonded to the corresponding battery pack sidewall using thermally conductive adhesive, and each heating unit is also provided with a binding steel strap on its exterior.

[0018] As a preferred embodiment, each of the heating units covers the two corners of the side wall of its respective battery pack.

[0019] As a preferred embodiment, the active temperature control system also acquires the status information of each cell in the battery pack and adjusts the safety threshold based on the status information of each cell.

[0020] As a preferred embodiment, the status information of the battery cell includes health status, state of charge, and charging rate.

[0021] As a preferred embodiment, the active temperature control system also determines the cell consistency of the battery pack based on the health status of each cell, and sets the start-up delay of each heating unit in the rapid heating mode based on the cell consistency.

[0022] Secondly, embodiments of this specification provide a household battery pack device, including a battery pack with multiple cells arranged in a rectangular array and an active temperature control device for a household battery pack as described in the first aspect.

[0023] The beneficial effects of the technical solutions provided in some embodiments of this specification include at least the following:

[0024] 1. Significantly Improved Heating Efficiency: Compared to traditional bottom heating solutions, this system employs a multi-lateral, coordinated three-dimensional heating layout, fully utilizing the maximum effective heat dissipation area of ​​the battery cell to achieve efficient and even heat transfer. Actual test data shows that the time required to heat from -10℃ to 15℃ can be reduced by more than 40%, significantly improving the user experience in low-temperature environments.

[0025] 2. Breakthrough Improvement in Temperature Uniformity: By addressing the "hot in the middle, cold at both ends" temperature distribution characteristics of the battery pack, an end-face heating unit is designed to precisely supplement heat in low-temperature areas. Combined with an intelligent temperature equalization mode, the maximum temperature difference between cells can be stably controlled within a very small range of ±3℃. This fundamentally solves the problem of inconsistent battery pack performance degradation caused by uneven temperature.

[0026] 3. System security and reliability have been comprehensively improved:

[0027] Preventing safety risks: A rapid and uniform heating strategy can effectively suppress the formation of lithium dendrites during low-temperature charging, thereby reducing the risk of thermal runaway from the source.

[0028] Extended cycle life: Excellent temperature uniformity ensures that the aging rate of each cell in the battery pack is synchronized, which is expected to extend the overall cycle life by more than 20%.

[0029] Reliable mechanical connection: The dual fixing technology of thermally conductive adhesive layer and steel strip binding ensures that the heating unit and the surface of the battery cell are in close contact for a long time under thermal expansion and contraction, which guarantees the long-term stability of the heating effect. It has been tested and can meet the service life requirements of more than 10 years.

[0030] Dynamic safety protection: Based on the cell health status (SOH) and state of charge (SOC), the heating threshold and start-up sequence are dynamically adjusted to provide personalized protection for aging or inconsistent batteries, further enhancing the system's adaptability and safety.

[0031] 4. Optimization of operational energy efficiency and economic benefits:

[0032] Reduced energy consumption: The intelligent multi-mode control strategy can accurately apply heating power according to actual needs, avoiding ineffective heating, and reducing daily operating energy consumption by more than 15%.

[0033] Cost advantage: The modular system design is compatible with different cell arrangements and capacities, reducing production and maintenance costs. While achieving excellent performance, it also possesses good economic efficiency, facilitating large-scale deployment.

[0034] 5. Significantly enhanced environmental adaptability: The solution can operate reliably in extreme low-temperature environments of -20℃, and the rapid heating mode can ensure that the battery can quickly recover its performance under extreme conditions, greatly expanding the application boundaries of residential energy storage in cold regions.

[0035] 6. Improved manufacturing process and long-term stability: The design of the heating unit covering the corner of the side wall not only strengthens the heating of weak points, but also effectively avoids problems such as the thermal conductive adhesive layer curling at the corners, improving the product's manufacturing yield and long-term reliability. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of an active temperature control device for a household battery pack provided in the embodiments of this specification.

[0038] Figure 2 This is a flowchart illustrating the operation of an active temperature control device for a household battery pack, as provided in the embodiments of this specification. Detailed Implementation

[0039] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings.

[0040] The terms "first," "second," "third," etc., in the description, claims, and accompanying drawings are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0041] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the described elements without departing from the scope of this specification. Various processes or components may be appropriately omitted, substituted, or added to the examples. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Furthermore, features described with respect to some examples may be combined into other examples.

[0042] In residential energy storage scenarios, lithium battery packs need to operate stably under various climatic conditions. When the ambient temperature drops, the batteries face severe challenges, and their need for low-temperature heating stems primarily from preventing the following key hazards:

[0043] 1. Severe Performance Degradation and Safety Risks: Low temperatures increase the viscosity of the electrolyte inside the battery and cause a sharp drop in ion migration rate, resulting in a significant increase in internal resistance and rapid decay of usable capacity. More seriously, when charging at low temperatures, the deposition kinetics of lithium ions on the negative electrode surface become unbalanced, making it easy for metallic lithium to precipitate and form lithium dendrites. These dendrites may puncture the battery separator, causing internal short circuits, which are a direct cause of catastrophic safety accidents such as thermal runaway, fire, or even explosion.

[0044] 2. Impaired Lifespan and Reliability: In addition to the acute safety risks mentioned above, low temperatures and inappropriate heating methods can also cause chronic damage. Common unidirectional heating (such as bottom heating) can lead to a significant temperature gradient inside the battery pack, resulting in an uneven distribution of "hot in the middle and cold at both ends." This temperature inconsistency accelerates the performance degradation of individual cells within the battery pack, creating a bottleneck effect, thereby significantly shortening the overall cycle life and long-term reliability of the battery pack.

[0045] Therefore, to ensure the safe operation, performance, and long-term durability of residential energy storage batteries in low-temperature environments, a rapid, uniform, and intelligent heating management system is an indispensable key technology. This solution is proposed to address this core need.

[0046] Example 1

[0047] An active temperature control device for household battery packs

[0048] like Figure 1 As shown, an active temperature control device for a household battery pack is provided. The battery pack includes multiple cells 1 arranged in a rectangular array. The active temperature control device includes a temperature sensor disposed on each cell 1, multiple heating units 2 disposed on each side wall of the battery pack, and an active temperature control system.

[0049] Each temperature sensor detects the temperature value of its corresponding cell 1;

[0050] The active temperature control system acquires the temperature value of each corresponding cell 1 output by each temperature sensor, and sets the heating power of each heating unit 2 based on the temperature value of each cell 1 and the relative position of each cell 1 in the battery pack.

[0051] Each heating unit 2 heats the battery pack based on its corresponding heating power output by the active temperature control system.

[0052] This embodiment provides an active temperature control device for household battery packs. Its core lies in the strategy of combining distributed temperature sensing with directional adjustable power heating to achieve precise and efficient management of the internal temperature field of the battery pack, so as to solve the problems of battery performance degradation and lifespan reduction caused by uneven temperature in low-temperature environments.

[0053] Illustratively, the active temperature control device comprises three main parts: a temperature sensing module, a heating execution module, and an intelligent control module. The temperature sensing module consists of temperature sensors mounted on each cell 1, ensuring comprehensive and accurate temperature data acquisition. It can monitor the temperature status of each individual cell 1 within the battery pack in real time, providing a data foundation for precise temperature control. The heating execution module consists of multiple heating units 2 arranged on the side walls of the battery pack (i.e., the front, rear, left, and right sides), which together form a "four-sided enveloping" heating surface. The control center is the active temperature control system, which receives data from all temperature sensors, performs calculations and analysis, and independently controls the operating power of each heating unit 2.

[0054] Explaining the underlying principle, this solution operates as a closed-loop dynamic optimization process. After acquiring the real-time temperature values ​​of all cells 1, the active temperature control system not only analyzes the absolute temperatures (such as minimum and maximum temperatures), but more importantly, it combines this with the relative position information of each cell 1 within the rectangular array to make a comprehensive decision. Due to the heat accumulation effect within the battery pack, cells 1 located at the center have poorer heat dissipation conditions, and their temperatures are typically higher than those at the edges. To address this physical characteristic, the control strategy of this solution includes optimizations at two levels: spatial layout optimization and power distribution optimization.

[0055] In terms of spatial layout, this solution creatively abandons the traditional bottom heating or theoretically possible six-sided fully enclosed heating structure, and specifically chooses not to set heating units 2 on the top and bottom surfaces of the battery pack. This design intentionally avoids direct heating of the central cell 1 from both the top and bottom, thereby effectively reducing the heat accumulation effect of the central cell 1, preventing it from overheating and thus suppressing the expansion of the internal temperature difference of the battery pack from the source.

[0056] In terms of power distribution, the active temperature control system calculates and sets differentiated heating power for heating units 2 at different locations based on the real-time monitoring of the temperature distribution of each cell 1. For example, higher power can be allocated to heating units 2 in areas of low-temperature cells 1 for focused heating, while lower power or shutdown can be allocated to heating units 2 in areas of high-temperature cells 1. This dynamic and non-uniform power allocation based on the statistical results of the temperature field within the battery pack allows for more precise "on-demand" distribution of heating heat, targeted compensation for low-temperature areas, thereby rapidly and evenly raising the overall battery temperature and effectively reducing the maximum temperature difference between cells 1.

[0057] This device, through a synergistic mechanism of "comprehensive sensing, surrounding heating, and intelligent control," not only significantly improves low-temperature heating efficiency but, more importantly, greatly enhances the uniformity of temperature within the battery pack by suppressing central overheating and directional compensation for edge low temperatures. This directly alleviates the differences in performance degradation rates among individual cells caused by temperature inconsistencies, thereby improving the long-term cycle life and overall reliability of the battery pack. Simultaneously, avoiding ineffective full-power heating and overheating of the central area also results in higher energy efficiency, reducing unnecessary energy consumption and meeting the dual requirements of economy and reliability for residential energy storage products.

[0058] In one embodiment of this specification, when there is a cell 1 with a temperature value lower than the safety threshold, the active temperature control system is set to a rapid heating mode in which each heating unit 2 heats up at maximum power.

[0059] When the temperature of each cell 1 is greater than the safety threshold and the maximum temperature difference of each cell 1 is greater than the equalization threshold, the active temperature control system determines the nearest heating unit 2 based on the relative position of the cell 1 with the lowest temperature in the battery pack, and sets the nearest heating unit 2 to a temperature equalization mode that heats up at maximum power.

[0060] When the temperature of each cell 1 is greater than the safety threshold, the maximum temperature difference of each cell 1 is less than the equilibrium threshold, and there is a cell 1 with a temperature lower than the ideal threshold, the active temperature control system obtains the adaptive heating power corresponding to each heating unit 2 based on the temperature difference between each cell 1 and the ideal threshold and the relative position of each cell 1 in the battery pack, and sets it to a conventional heating mode in which each heating unit 2 heats up with its corresponding adaptive heating power.

[0061] This embodiment further defines the specific control method of the active temperature control system. Through layered, multi-mode intelligent decision-making logic, it dynamically manages the heating process to balance heating speed, temperature uniformity, and energy efficiency. Its core lies in automatically switching between three operating modes based on the real-time temperature field of the battery pack: rapid heating mode, uniform temperature mode, and conventional heating mode.

[0062] Explanatory, Rapid Heating Mode: This mode has the highest priority and is designed to address the safety risks posed by extreme low temperatures. When the system detects that the temperature of any single cell 1 is below a preset safety threshold (e.g., -10°C), this mode will be immediately triggered for emergency rapid heating. In this mode, the system will determine that the entire battery pack is in a dangerously low temperature state, and the primary task is to quickly move it out of this dangerous range. Therefore, all heating units 2 are set to operate at maximum power to rapidly and fully heat the battery pack.

[0063] Temperature Equalization Mode: After the battery pack is removed from extreme low temperatures, this mode primarily addresses the issue of uneven internal temperature. Its trigger condition is: the temperature of all cells 1 is already above the aforementioned safety threshold, but due to differences in heating, heat dissipation, and heat accumulation effects among the cells 1, the maximum temperature difference between them exceeds a preset equalization threshold (e.g., 8°C). In this case, the control objective shifts from overall temperature increase to reducing the temperature difference. The system locates one or more cells 1 with the lowest temperature and, based on their relative position within the battery pack, identifies the nearest heating unit 2. Subsequently, the system activates only these "nearest neighbor heating units 2" and operates them at maximum power, thereby providing precise and efficient heat replenishment to the low-temperature area to quickly reduce the maximum temperature difference within the battery pack until the temperature difference is reduced to the target range or the stop condition is triggered.

[0064] Conventional Heating Mode: This mode operates under the premise of basic assurance of safety and consistency, with a focus on energy efficiency optimization during the heating process. Its triggering conditions are: the temperature of each cell 1 is above the safety threshold, the maximum temperature difference between cells 1 is less than the equilibrium threshold, but there are cells 1 whose temperature is below the ideal operating threshold (e.g., 5°C). In this mode, the system raises the overall temperature of the battery pack to the ideal range in a relatively gentle and energy-efficient manner. Based on the temperature difference between each cell 1 and the ideal threshold, and combined with its location information, the system comprehensively calculates the optimal power required for each heating unit 2, i.e., assigning an "adaptive heating power" to each heating unit 2. Typically, higher power is assigned to heating units 2 near low-temperature cells 1, and lower or even zero power is assigned to heating units 2 near high-temperature cells 1. All heating units 2 operate according to this customized power.

[0065] In addition to the three modes mentioned above, the system may also include a unified heating stop condition and a standby mode that does not perform heating. The three heating modes share a unified heating stop condition: when the temperature of any cell 1 reaches a preset maximum safety threshold (e.g., 15°C), all heating immediately stops, regardless of the current mode, to prevent the overall battery pack temperature from becoming too high. Prolonged high cell 1 temperatures significantly accelerate internal side reactions, such as electrolyte decomposition and continuous thickening of the positive and negative electrode interface film (SEI film). This irreversibly consumes active lithium ions and electrolyte, leading to accelerated capacity decay and continuous increase in internal resistance, thereby shortening the battery pack's cycle life. When the system detects that the temperature of all cells 1 is not lower than the ideal threshold, and the maximum temperature difference between cells 1 does not exceed the equilibrium threshold, the battery pack is determined to be in a suitable and uniform temperature state. At this time, the active temperature control system will not activate any heating unit 2, and the system enters a low-power monitoring standby state.

[0066] This embodiment employs a multi-level collaborative approach—"rapid heating mode for safety, uniform temperature mode for even heating, and conventional heating mode for improved energy efficiency"—combined with clearly defined stop and standby conditions, to form a complete and adaptive closed-loop temperature control logic. Under the core premise of ensuring battery safety and delaying inconsistent battery pack degradation, it intelligently allocates heating resources to achieve rapid, uniform, and efficient battery thermal management.

[0067] In one embodiment of this specification, the active temperature control system obtains the adaptive heating power corresponding to each heating unit 2 based on the temperature difference between each cell 1 and the ideal threshold and the relative position of each cell 1 in the battery pack, specifically:

[0068] For any heating unit 2, the adaptive heating power corresponding to the heating unit 2 is obtained based on the temperature difference between each cell 1 from the center cell 1 to the side of the battery pack where the heating unit 2 is located and the ideal threshold, and the distance from the center cell 1.

[0069] Explained in this embodiment, for any heating unit 2 on the sidewall of the battery pack, the temperature is determined by a calculation model that comprehensively considers the relationship between temperature requirements and heat transfer. This model uses the central cell 1 as the thermal field reference point and calculates the temperature state of each cell 1 along the path from the central cell 1 to the edge of the battery pack on the side where the heating unit 2 is located. The calculation mainly considers two core factors: first, the difference between the actual temperature of each cell 1 and the ideal threshold (e.g., 5°C), which directly reflects the urgency of the heating requirement at that point; and second, the physical distance between each cell 1 and the central cell 1, which reflects the spatial resistance that must be overcome for heat to transfer from the heating unit 2 to that cell 1.

[0070] The system weights and sums the temperature differences of all cells 1 along the aforementioned path with their corresponding distances to calculate the adaptive heating power required to drive the heating unit 2. Cells 1 that are closer to the heating unit 2 and have lower temperatures have a greater weight in influencing the final power value. For example, for a heating unit 2 designed to raise the temperature of the right-side low-temperature region, its power will be primarily determined by the temperature and position of each cell 1 along its heating path (from the center to the right), potentially resulting in a higher power value. Conversely, for a heating unit 2 facing a region already close to its ideal temperature, even if its adjacent cells 1 are at a relatively acceptable temperature, the presence of distant low-temperature cells 1 along its heating path may result in a medium power allocation. A heating unit 2 facing a high-temperature region may be allocated zero power.

[0071] The advantage of this calculation method lies in achieving targeted and adjustable precise thermal management. It guides the system to prioritize and fully allocate heating power to the heating unit 2 most effective in improving the low-temperature region, while suppressing heating units 2 that might exacerbate overheating in the central region. For example, when the system detects that the temperature of the central cell 1 is rising too rapidly, this algorithm can automatically reduce the power of the heating units 2 on the sides closer to the central cell 1, while maintaining or increasing the power of the heating units 2 on the sides farther from the central cell 1. This achieves the effect of primarily supplementing the low-temperature region with heat, rather than providing average overall heating. This effectively avoids the risk of overheating in the central region due to the pursuit of overall temperature rise in conventional heating modes. It ensures that while raising the overall battery temperature, the heating process always strives to minimize the internal temperature difference and control the overall temperature within the ideal operating range, thus achieving the best balance between energy efficiency, uniformity, and safety.

[0072] In one embodiment of this specification, the active temperature control system also obtains the adaptive heating power corresponding to each heating unit 2 based on the temperature value of the central battery cell 1.

[0073] To illustrate, lithium batteries not only have low-temperature limitations but also an optimal operating temperature range. Overheating for temperature equalization can cause localized temperatures within the battery pack (especially in the central cell 1) to reach higher ranges, leading to accelerated battery life degradation at high temperatures. Even with a heating stop condition set, conventional heating methods may prematurely trigger the heating stop, resulting in poor temperature equalization.

[0074] Explained, this embodiment introduces the temperature of the central battery cell 1 as a global constraint and adjustment factor to achieve finer power distribution and prevent the risk of overheating in the central area during the pursuit of overall heating or temperature uniformity. Based on power calculations using the temperature difference between each battery cell 1 and the ideal threshold, and their location, an independent consideration of the temperature value of the central battery cell 1 is added. The system compares the real-time acquired temperature value of the central battery cell 1 with a preset upper temperature threshold (e.g., the highest safe threshold in a conventional heating mode, such as 15°C). Then, the system uses the difference between the temperature of the central battery cell 1 and this upper threshold as a global adjustment coefficient, dynamically applying it to the initial adaptive heating power calculated for each heating unit 2.

[0075] For example: When the temperature of the central cell 1 approaches the upper limit threshold, it indicates that the heat accumulation effect in the central region of the battery pack is very significant, posing a risk of overheating. At this time, the system will proportionally reduce the final output power of all heating units 2 (especially those units that may exacerbate heating in the central region) based on the difference between the temperature of the central cell 1 and the upper limit threshold, and may even set the power of some units to zero. Conversely, when the temperature of the central cell 1 is low and far from the upper limit threshold, the system's constraint on heating power will be relaxed, allowing each heating unit 2 to operate more fully according to its initial calculated power to quickly raise the temperature of the overall system or the low-temperature region.

[0076] It achieves closed-loop control that combines demand-driven and safety-constrained operation. It not only responds to the heating needs of each local area but also directly embeds the safety objective of preventing central overheating into the power distribution algorithm. For example, in normal heating mode, even if edge cell 1 still needs heating, if the temperature of center cell 1 has risen to the warning level, the system will automatically reduce the overall heating intensity, slow down the temperature rise, prioritize preventing local overheating and triggering the stop condition, and strive for overall temperature balance. Thus, while improving low-temperature performance and optimizing temperature uniformity, it fundamentally ensures the long-term safety and reliability of the system.

[0077] In one embodiment of this specification, each heating unit 2 is bonded to the corresponding battery pack sidewall using thermally conductive adhesive, and each heating unit 2 is also provided with a binding steel strip 3 on its exterior.

[0078] Illustratively, each heating unit 2 is attached to the sidewall of the battery pack via a dual fixing mechanism: firstly, it is bonded with thermally conductive adhesive, and secondly, a binding steel strip 3 is applied externally. This "composite fixing strategy combining mechanical and chemical methods" addresses the challenges posed by thermal expansion and contraction of the battery during operation, ensuring a persistently tight heating interface and thus maintaining stable thermal conductivity.

[0079] Explain that during battery charging, discharging, and temperature changes, cell 1 undergoes volume changes. To address thermal expansion, this design employs a binding steel strip 3. During assembly, the steel strip is subjected to a precisely calculated pre-tension force, forming a rigid constraint frame. Its primary function is to limit the lateral expansion deformation of cell 1, preventing structural failure due to excessive expansion. Simultaneously, the thermally conductive adhesive layer located between heating unit 2 and the battery pack sidewall acts as a buffer during this process. The adhesive has a certain degree of elasticity, absorbing and dispersing localized stress generated by expansion, preventing stress concentration from damaging cell 1 or heating unit 2, thus mitigating the potential risk of "over-tightening."

[0080] The thermally conductive adhesive bonding addresses the core requirements of cold shrinkage and ensuring heating efficiency. After curing, the thermally conductive adhesive layer forms a strong chemical bond with the surface of the heating film and the sidewall shell of cell 1. This bonding force does not depend on continuous mechanical pressure. Therefore, when the battery shrinks in a low-temperature environment, even if the pre-tension of the steel strip loosens, the adhesive interface can always maintain a bonded state, preventing gaps from forming between the heating unit 2 and the surface of cell 1 due to shrinkage.

[0081] Together, they ensure that the heating unit 2 and the surface of the battery cell 1 maintain long-term and close physical contact regardless of cold or hot cycling, minimizing thermal resistance and thus guaranteeing the consistency and reliability of the heating effect, so as to achieve long-term stable and efficient temperature control management.

[0082] In one embodiment of this specification, each heating unit 2 covers the two corners of the side wall of its respective battery pack.

[0083] Explained from a thermal perspective, the corners of the battery pack, due to their three-dimensional exposure, have the largest heat dissipation area and the fastest heat loss, making them the areas most prone to low-temperature dead zones in traditional heating schemes. This embodiment extends the heating unit 2 to cover both corners of the sidewall, directly enhancing the heating of the weakest points where heat dissipation is fastest, ensuring that heat can be effectively injected into these areas that conventional heating methods struggle to reach. Simultaneously, the overlapping layout of adjacent heating units 2 means that at the seams or boundaries of the battery pack sidewalls, a superposition of heating power and a seamless connection of the thermal field are formed, eliminating heating blind spots that might occur due to gaps between the heating units 2.

[0084] From a mechanical and technological perspective, corner areas are stress concentration and deformation-sensitive locations. If heating unit 2 is not completely covered, the thermally conductive adhesive is prone to lifting and peeling at the corner edges due to long-term thermal cycling or structural deformation. These problems directly lead to poor contact between heating unit 2 and the surface of battery cell 1, resulting in localized high thermal resistance and severely affecting heating efficiency and temperature uniformity. By completely covering the corner with heating unit 2, the adhesive area is increased, enhancing the overall integrity of the bonding structure. This more effectively disperses stress, suppresses edge lifting, and ensures long-term, tight contact at the heating interface.

[0085] This design not only optimizes the heat field distribution, but also ensures the stability of the dual mechanical and chemical fixation effect in terms of manufacturing process and long-term reliability, fundamentally guaranteeing the durability and consistency of heating performance.

[0086] In one embodiment of this specification, the active temperature control system also acquires the status information of each cell 1 in the battery pack and adjusts the safety threshold based on the status information of each cell 1.

[0087] Explained, this embodiment introduces a deep perception and dynamic decision-making capability of the internal state of the battery pack, thereby optimizing the basic temperature threshold control strategy. The active temperature control system not only monitors the surface temperature of each cell 1, but also acquires and integrates the real-time state information of each cell 1 through the battery management system (BMS), dynamically adjusting key thresholds in the heating control strategy. Here, the state information is a comprehensive set of parameters that transcends a single temperature dimension. This transforms the control logic from relying on fixed, universal temperature thresholds to dynamically and adaptively adjusting thresholds based on real-time, personalized battery states. This intelligent enhancement brings multiple beneficial effects. It can provide "tailor-made" thermal protection for batteries at different aging stages and operating conditions, implementing earlier intervention after battery performance degradation to prevent safety risks; simultaneously, it avoids unnecessary premature heating when the battery is in a healthy state, thereby further optimizing the system's energy efficiency while ensuring fundamental safety, and contributing to better battery life management. This transforms the thermal management system from a relatively passive execution unit into an active intelligent system capable of deeply understanding battery health and co-evolving with it.

[0088] In one embodiment of this specification, the status information of cell 1 includes health status, state of charge, and charging rate.

[0089] Explained, as cell 1 ages, its internal active materials decay, electrolyte decomposes and is consumed, and the SEI film thickens. This leads to a continuous increase in internal resistance and a further decrease in lithium-ion diffusion capacity. For severely aged batteries, at relatively high temperatures (e.g., -5°C or even 0°C), their internal electrochemical conditions may be comparable to those of healthy batteries at -10°C, significantly increasing the risk of lithium dendrite formation. Therefore, the lower the SOH (the worse the health), the higher the temperature threshold for triggering protective heating should be, i.e., earlier and gentler heating intervention should be implemented.

[0090] Lithium dendrites are most likely to form during charging, especially when the negative electrode is close to full lithium insertion. When the state of charge (SOC) is very high (e.g., >90%), the interlayer lithium insertion sites in the graphite negative electrode tend to be saturated, making it more difficult for newly arrived lithium ions to insert and more likely to deposit metallic lithium on the surface. When charging in the high SOC range, the temperature threshold for triggering heating should be increased (i.e., preheating) to ensure that the battery is charged at the end of the process at a more suitable temperature, thereby improving lithium ion insertion kinetics and suppressing dendrites. Conversely, in the low SOC range, the threshold can be appropriately relaxed.

[0091] High-rate charging means a greater flux of lithium ions needs to be embedded into the negative electrode per unit time. At low temperatures, lithium ion diffusion is slow, which cannot meet the high flux requirements, easily leading to lithium ion "depletion" on the negative electrode surface and causing dendrite growth. When the system is planning or in the process of high-rate charging, the heating trigger temperature threshold should be significantly increased to ensure that the battery operates at a temperature sufficient to support the charging rate. For trickle charging, the threshold can be appropriately relaxed.

[0092] In one embodiment of this specification, the active temperature control system further determines the consistency of the battery cells 1 in the battery pack based on the health status of each cell 1, and sets the start-up delay of each heating unit 2 in the rapid heating mode based on the consistency of the cell 1.

[0093] Illustratively, this embodiment further optimizes the start-up process of the rapid heating mode by introducing a refined timing control strategy based on the internal consistency of the battery pack, which aims to improve the safety of the heating process, especially for battery packs with inconsistent aging.

[0094] Explanatoryly, the active temperature control system not only responds to temperature-triggered emergency heating demands but also proactively assesses the health status of the battery pack and fine-tunes the timing of heating actions accordingly. In practice, the system first determines the consistency of cell 1 across the entire battery pack based on the State of Health (SOH) parameters of each cell 1. SOH is a key indicator reflecting the aging degree of cell 1; a large dispersion in the SOH values ​​of cells 1 within the pack indicates the presence of a lagging "weak" cell 1, which typically has higher internal resistance and is more sensitive to thermal and electrical stress. Then, based on the assessed consistency level of cell 1, the system sets differentiated "start-up delays" for different heating units 2, rather than instantaneously synchronizing all heating units 2 at maximum power in rapid heating mode. For battery packs with excellent consistency, where the aging degree and thermal characteristics of all cells 1 are similar, the system can maintain the original design, allowing the heating units 2 to start up quickly and synchronously to achieve the fastest overall temperature rise. However, for battery packs with poor consistency, if synchronous full-power heating is still used, the huge instantaneous heat flow may cause the temperature of the aged cell 1 with increased internal resistance or its adjacent area to rise too quickly, exacerbating local electrothermal stress and posing a potential risk of inducing thermal runaway. In this case, by introducing a stepped start-up delay for heating units 2 at different locations (e.g., prioritizing shorter delays for heating units 2 near healthy cells 1 and longer delays for heating units 2 near aged "weak" cells 1), a smooth loading of heating power in time and space can be achieved. This control method allows heat to be injected into the battery system more gradually and controllably, effectively avoiding damage to weak cells 1 caused by power surges. While ensuring rapid removal from dangerously low temperatures, it significantly enhances the safety of the rapid heating process, and is particularly beneficial for extending the remaining service life of battery packs that have already shown inconsistent aging.

[0095] Workflow:

[0096] like Figure 2 As shown, after the system is powered on, it first performs data acquisition, continuously acquiring the temperature data of each cell 1.

[0097] Based on the collected temperature data, the system makes judgments in the following order and enters the corresponding working mode:

[0098] Level 1: Rapid Heating Mode Judgment. Determine if any cell 1 has a temperature < -10℃.

[0099] Yes: Enter the rapid heating mode, turn on all heating units 2 to heat at full capacity until the highest temperature of any cell 1 is >15℃ and then stop heating.

[0100] No: Proceed to the next level of judgment.

[0101] Level 2: Temperature Equalization Mode Judgment. Determine whether the maximum temperature difference ΔTmax between cells 1 is greater than 8℃.

[0102] Yes: Enter the uniform temperature mode, only turn on the heating unit 2 of the nearest lowest temperature cell 1 for directional supplemental heating, and stop heating when △Tmax<3℃.

[0103] No: Proceed to the next level of judgment.

[0104] Level 3: Normal heating mode judgment. Determine whether the minimum temperature of cell 1 is <5℃.

[0105] Yes: Enter the normal heating mode, turn on all heating units 2 to heat until the highest temperature of any cell 1 is >15℃ and then stop heating.

[0106] No: The system determines that the battery pack temperature is already in good condition and will not activate the heating.

[0107] Cyclic execution: After any heating mode stops, or when the conditions for starting any heating mode are not met, the system will return to the data acquisition step and start a new round of monitoring and judgment, thereby achieving continuous and adaptive closed-loop temperature control.

[0108] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0109] Example 2

[0110] A household battery pack device

[0111] See attached document Figure 1 The residential battery pack device includes a battery pack with multiple cells 1 arranged in a rectangular array and an active temperature control device for a residential battery pack as described in Example 1.

[0112] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the residential battery pack device embodiments are basically similar to the active temperature control device embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the active temperature control device embodiments.

[0113] The embodiments described above are merely preferred embodiments of this specification and are not intended to limit the scope of this specification. Any modifications and improvements made by those skilled in the art to the technical solutions of this specification without departing from the spirit of this specification should fall within the protection scope defined by the claims of this specification.

Claims

1. An active temperature control device for a household battery pack, the battery pack comprising multiple cells arranged in a rectangular array, characterized in that: This includes a temperature sensor installed on each cell, multiple heating units installed on each side wall of the battery pack, and an active temperature control system; Each of the temperature sensors detects the temperature value of its corresponding battery cell; The active temperature control system acquires the temperature value of each corresponding cell output by each temperature sensor, and sets the heating power of each heating unit based on the temperature value of each cell and the relative position of each cell in the battery pack. Each of the heating units heats the battery pack based on its corresponding heating power output by the active temperature control system.

2. The active temperature control device for a household battery pack according to claim 1, characterized in that: When there are battery cells with temperatures below the safety threshold, the active temperature control system is set to a rapid heating mode where each heating unit heats up at maximum power. When the temperature of each cell is greater than the safety threshold and the maximum temperature difference between the cells is greater than the equalization threshold, the active temperature control system determines the nearest heating unit based on the relative position of the cell with the lowest temperature in the battery pack, and sets the nearest heating unit to a temperature equalization mode that heats up at maximum power. When the temperature of each cell is greater than the safety threshold, the maximum temperature difference between each cell is less than the equilibrium threshold, and there are cells with temperatures lower than the ideal threshold, the active temperature control system obtains the adaptive heating power corresponding to each heating unit based on the temperature difference between each cell and the ideal threshold and the relative position of each cell in the battery pack, and sets it to a conventional heating mode in which each heating unit heats up with its corresponding adaptive heating power.

3. The active temperature control device for a household battery pack according to claim 2, characterized in that: The active temperature control system obtains the adaptive heating power of each heating unit based on the temperature difference between each cell and the ideal threshold and the relative position of each cell in the battery pack. Specifically: For any heating unit, the adaptive heating power is obtained based on the temperature difference between each cell from the central cell to the side of the battery pack where the heating unit is located and the ideal threshold, as well as the distance from the central cell.

4. The active temperature control device for a household battery pack according to claim 3, characterized in that: The active temperature control system also obtains the adaptive heating power of each heating unit based on the temperature value of the central battery cell.

5. The active temperature control device for a household battery pack according to claim 1, characterized in that: Each heating unit is bonded to the corresponding battery pack sidewall with thermally conductive adhesive, and each heating unit is also provided with a binding steel strap on the outside.

6. The active temperature control device for a household battery pack according to claim 1, characterized in that: Each of the heating units covers the two corners of the side wall of its respective battery pack.

7. The active temperature control device for a household battery pack according to claim 2, characterized in that: The active temperature control system also acquires the status information of each cell in the battery pack and adjusts the safety threshold based on the status information of each cell.

8. The active temperature control device for a household battery pack according to claim 7, characterized in that: The cell's status information includes its health status, state of charge, and charging rate.

9. The active temperature control device for a household battery pack according to claim 8, characterized in that: The active temperature control system also judges the cell consistency of the battery pack based on the health status of each cell, and sets the start-up delay of each heating unit in fast heating mode based on the cell consistency.

10. A household battery pack device, characterized in that: The battery pack includes a plurality of cells arranged in a rectangular array and an active temperature control device for a residential battery pack as described in any one of claims 1-9.

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