Battery thermal management system

Abstract

The invention relates to the technical field of new energy vehicles, in particular to a battery thermal management system. Through the combination of the multi-channel switch and the bidirectional DC-DC converter, the system can flexibly adjust the function distribution of the energy storage unit, so that the system can dynamically adjust the configuration of the thermal management power supply unit and the key energy storage unit according to actual requirements and working conditions, thereby improving the adaptability and resource utilization efficiency of the system. Each energy storage unit is provided with an independent heating / cooling module, and a differential heat management strategy is adopted, so that the system can accurately control the specific condition of each energy storage unit. By logically dividing the functional units, the system can distribute energy resources more reasonably. The thermal management power supply unit is specially used for supporting a thermal management function, and the key energy storage unit ensures the power supply demand of the main load, so that the mutual interference between the thermal management demand and the main load demand can be effectively prevented, and the stability and reliability of the system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a battery thermal management system. Background Art

[0002] With the rapid development of electric vehicles and new energy technologies, batteries, as key components, have a direct impact on the efficiency and reliability of the entire system through their performance and lifespan. Traditional battery management systems usually adopt a unified management strategy, which is difficult to meet the differentiated needs under complex working conditions, resulting in the inability to fully utilize battery performance, shortened lifespan, and even safety hazards.

[0003] In the prior art, the battery thermal management system usually includes a dedicated independent battery to power the thermal management module. This results in low integration and low energy efficiency of the system. Although the use of an independent battery to power the thermal management module improves reliability, it increases the complexity, weight and cost of the system. At the same time, subsystems such as thermal management, energy recovery, and battery management often operate independently and lack an effective coordination mechanism. This not only results in the inability to effectively share and optimize the energy between the main battery pack and the thermal management battery, reducing the overall energy efficiency, but also makes it difficult to achieve overall optimization of the system. In view of the above problems, there is an urgent need for an advanced battery thermal management system that can overcome the limitations of existing technologies and achieve more efficient, smarter and more integrated battery management. Summary of the invention

[0004] In order to solve the above problems, the present invention discloses a battery thermal management system.

[0005] The present application discloses a battery thermal management system, comprising: A battery pack, comprising a plurality of energy storage units with the same physical characteristics, each of the energy storage units being electrically connected to a busbar and a bidirectional DC-DC converter through a multi-channel switch, each channel of the multi-channel switch being a bidirectional switch, and the plurality of energy storage units being logically divided into a plurality of functional units; A thermal management module, including a heating / cooling module respectively arranged corresponding to each energy storage unit, for independently controlling each heating / cooling module according to a differentiated thermal management strategy; A power supply management module, electrically connected to the battery pack and the thermal management module, respectively, and used to control the adjustment of the functional units in the battery pack according to feedback information from the battery pack and the thermal management module; The adjustment includes: the battery pack is logically divided into at least a thermal management power supply unit and a key energy storage unit; for the energy storage unit designated as the thermal management power supply unit, the connection between the energy storage unit and the bidirectional DC-DC converter is opened through the power supply management module; For the energy storage unit designated as a key energy storage unit, the power supply management module opens the connection between the energy storage unit and the busbar.

[0006] The power supply management module realizes the series-parallel configuration of multiple energy storage units by controlling the multi-channel switch and the bidirectional DC-DC converter, including: Series mode: multiple energy storage units are connected in sequence through multi-channel switches, and the total output voltage is adjusted using a bidirectional DC-DC converter; Parallel mode: Multiple energy storage units are connected in parallel through multi-channel switches, and the total output current is adjusted using a bidirectional DC-DC converter.

[0007] In addition, the system further includes a road condition detection unit, and the thermal management module adjusts the temperature of each functional unit according to the real-time driving road condition detected by the road condition detection unit, specifically including: When it is detected that the vehicle is in an uphill or high-speed driving state, the temperature of the key energy storage unit is actively reduced to ensure its stability under continuous high-power discharge conditions.

[0008] In the above solution, the heating / cooling module includes a thermoelectric cooling sheet and a heating film, and the two are integrated on the same heat dissipation substrate to achieve a two-way temperature regulation function.

[0009] The total number of energy storage units N required by the thermal management power supply unit is determined by the following formula: N = ceil(V / v) * ceil(P / (V * i)) * (1 + S); Where V is the required total voltage, P is the required total power, v is the rated voltage of a single energy storage unit, i is the maximum discharge current of a single energy storage unit, ceil() represents the upward rounding function, and S is the safety factor, which is calculated by the following formula: S = max(0, (Pr - Pa) / Pa + k * (1 - e)); Where Pr is the power required by the system, Pa is the power that the current configuration can provide, k is an adjustable weight coefficient ranging from 0 to 1, and e is the energy conversion efficiency of the system.

[0010] The weight coefficient k is associated with the working mode of the thermal management module, specifically including: When the thermal management module is in cooling mode, k = k_cool * (1 + P_cool / P_cool_max); When the thermal management module is in heating mode, k = k_heat * (1 + P_heat / P_heat_max); When the thermal management module is in standby mode, k = k_standby; Among them, k_cool, k_heat, and k_standby are preset basic weight values, P_cool and P_heat are the current cooling and heating powers, respectively, and P_cool_max and P_heat_max are the maximum cooling and heating powers.

[0011] The solution of the present application can flexibly adjust the functional allocation of energy storage units through the combination of multi-channel switches and bidirectional DC-DC converters, so that the system can dynamically adjust the configuration of thermal management power supply units and key energy storage units according to actual needs and working conditions, thereby improving the adaptability and resource utilization efficiency of the system. Each energy storage unit is equipped with an independent heating / cooling module, and a differentiated thermal management strategy is adopted, so that the system can accurately control the specific conditions of each energy storage unit, which not only helps to extend battery life, but also improves the energy efficiency and safety of the entire system. By logically dividing functional units, the system can allocate energy resources more reasonably. The thermal management power supply unit is specifically used to support thermal management functions, while the key energy storage unit guarantees the power supply needs of the main loads, which can effectively prevent mutual interference between thermal management needs and main load needs, and improve the stability and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the battery thermal management system in Example 1 of the present application; Figure 2 A schematic diagram of the connection between the energy storage unit, the busbar and the bidirectional DC-DC converter in an embodiment of the present application; Figure 3 Schematic diagram of the connection method of the functional units in the embodiment of the present application. DETAILED DESCRIPTION

[0013] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The principles and features of the present invention are described below in conjunction with the drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0014] The terms "including" and other expressions with similar meanings in the specification or claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions, such as a process, method or system, or device comprising a series of steps or units is not limited to the listed steps or units.

[0015] Example 1: Figure 1-2 As shown, a battery thermal management system includes: The battery pack 100 includes a plurality of energy storage units with the same physical characteristics, each of which is electrically connected to a busbar and a bidirectional DC-DC converter through a multi-channel switch, each channel of the multi-channel switch is a bidirectional switch, and the plurality of energy storage units are logically divided into a plurality of functional units; In one possible implementation, each energy storage unit is equipped with a three-channel switch, including three bidirectional channels: 1. Connecting to the busbar; 2. Connecting to the bidirectional DC-DC converter; 3. Self-isolation channel. Each channel contains a bidirectional switching element, which can be composed of a solid-state relay, a MOSFET or other suitable switching device. The bidirectional DC-DC converter can use a buck-boost structure. Channel connecting the busbar: This channel directly connects the energy storage unit and the main busbar of the system. When the channel is turned on, the energy storage unit can directly supply power to the system or charge from the system. The self-isolation channel is a switch channel connected to the multi-channel switch, which will isolate the energy storage unit from the entire system when disconnected. When the energy storage unit needs maintenance, replacement, or a fault is detected, after disconnecting this channel, the energy storage unit is disconnected from all other circuits to ensure safety and continuous operation of the system.

[0016] The thermal management module 200 includes a heating / cooling module 210 respectively arranged corresponding to each energy storage unit, and is used to independently control each heating / cooling module according to a differentiated thermal management strategy; wherein each energy storage unit is equipped with an independent thermoelectric cooler (TEC) and a heating film.

[0017] A power supply management module 300 is electrically connected to the battery pack and the thermal management module, respectively, and is used to control the adjustment of the functional units in the battery pack according to the feedback information of the battery pack and the thermal management module; the power supply management module may specifically use a processing module including an ARM / X86 chip; The adjustment includes: the battery pack is logically divided into at least a thermal management power supply unit and a key energy storage unit; for the energy storage unit designated as the thermal management power supply unit, the connection between the energy storage unit and the bidirectional DC-DC converter is opened through the power supply management module; For the energy storage unit designated as a key energy storage unit, the power supply management module opens the connection between the energy storage unit and the busbar.

[0018] Assume that the battery pack consists of 20 lithium-ion battery cells, with the default configuration of 15 cells as key energy storage cells and 5 cells as thermal management power supply cells. Dynamic adjustment threshold: When the ambient temperature is <0°C or >40°C, the number of thermal management power supply cells is increased to 8.

[0019] Cyclic use: The thermal management power supply units are rotated every 24 hours to achieve balanced use.

[0020] Differentiated thermal management strategies can include: Key energy storage unit: maintained at the optimal temperature range of 20-30°C; Thermally managed power supply units: allow for a wider temperature range (15-35°C), these units are preferred for system thermal management.

[0021] When the system starts, the power supply management module reads the status of each unit and divides the functional units according to the preset strategy and current status; controls the multi-channel switch to connect the corresponding units to the busbar or DC-DC converter; continuously monitors the status of all units, including voltage, current, temperature, etc.; independently controls the heating / cooling module of each unit according to the thermal management strategy; regularly (such as every 5 minutes) evaluates the system status and adjusts the functional unit division when necessary.

[0022] By logically partitioning and dynamically adjusting functional units, the system can optimize resource allocation based on real-time demand. This flexibility enables the system to maintain efficient operation under different working conditions and improve overall energy utilization. Independent heating / cooling modules allow the system to perform precise temperature management on each energy storage unit. This not only prolongs battery life, but also improves charging and discharging efficiency, especially in extreme temperature environments.

[0023] The power supply management module realizes the series-parallel configuration of multiple energy storage units by controlling the multi-channel switch and the bidirectional DC-DC converter, including: Series mode: multiple energy storage units are connected in sequence through multi-channel switches, and the total output voltage is adjusted using a bidirectional DC-DC converter; Parallel mode: Multiple energy storage units are connected in parallel through multi-channel switches, and the total output current is adjusted using a bidirectional DC-DC converter.

[0024] like Figure 3 As shown, specifically, each energy storage unit requires at least 3 bidirectional switches: S1: connected to the positive line of the DC-DC converter line; S2: connected to the negative line of the DC-DC converter line; S3: connected to the positive line of the next energy storage unit When configured in parallel: S1 of all units is closed (connected to the positive line of the DC-DC converter line); S2 of all cells is closed (connected to the negative line of the DC-DC converter line); S3 of all units is disconnected (to prevent short circuit between units); In series configuration: S1 of the first unit is closed (connected to the positive line of the DC-DC converter line); S2 of the last cell is closed (connected to the negative line of the DC-DC converter line); S3 of all the intermediate units are closed (forming a series chain); All other switches remain open.

[0025] Dynamic series-parallel configuration enables the system to operate over a wide voltage and current range to accommodate a variety of load requirements. This flexibility allows the same set of hardware to be applied to a variety of scenarios, improving the versatility and cost-effectiveness of the system.

[0026] In the above solution, the heating / cooling module includes a thermoelectric cooling sheet and a heating film, and the two are integrated on the same heat dissipation substrate to achieve a two-way temperature regulation function.

[0027] The heat dissipation substrate is made of metal materials with good thermal conductivity (such as aluminum alloy) and serves as the installation basis for the thermoelectric cooling sheet and the heating film. The thermoelectric cooling sheet uses semiconductor cooling sheets of appropriate specifications and is fixed on one side of the heat dissipation substrate by welding or thermal conductive glue. The cold end of the cooling sheet faces the controlled object, and the hot end is in close contact with the substrate. The heating film uses a flexible electric heating film and is fixed on the other side of the heat dissipation substrate by pasting or pressing. Thermal conductive silicone grease is applied between the heating film and the substrate to improve the heat conduction efficiency. A temperature sensor is installed on the surface of the heat dissipation substrate to monitor the module temperature in real time. The heating and cooling functions are integrated in a compact module. When cooling is required, the thermoelectric cooling sheet is started; when heating is required, the heating film is started. Accurate bidirectional temperature regulation function can be achieved through the adjustment of the control circuit. The heat dissipation substrate plays the role of heat transfer and heat dissipation in this process, which helps to improve the thermal efficiency of the entire module.

[0028] Embodiment 2: The total number N of energy storage units required by the thermal management power supply unit is determined by the following formula: N = ceil(V / v) * ceil(P / (V * i)) * (1 + S); Where V is the required total voltage, P is the required total power, v is the rated voltage of a single energy storage unit, i is the maximum discharge current of a single energy storage unit, ceil() represents the upward rounding function, and S is the safety factor, which is calculated by the following formula: S = max(0, (Pr - Pa) / Pa + k * (1 - e)); Where Pr is the power required by the system, Pa is the power that the current configuration can provide, k is an adjustable weight coefficient ranging from 0 to 1, and e is the energy conversion efficiency of the system.

[0029] The weight coefficient k is associated with the working mode of the thermal management module, specifically including: When the thermal management module is in cooling mode, k = k_cool * (1 + P_cool / P_cool_max); When the thermal management module is in heating mode, k = k_heat * (1 + P_heat / P_heat_max); When the thermal management module is in standby mode, k = k_standby; Among them, k_cool, k_heat, and k_standby are preset basic weight values, P_cool and P_heat are the current cooling and heating powers, respectively, and P_cool_max and P_heat_max are the maximum cooling and heating powers.

[0030] For example, it is assumed that the parameters of the thermal management system are as follows: System requirements: V = 48V (total voltage required), P = 1000W (total power required), Pr = 1100W (power required by the system); Energy storage unit parameters: v = 3.7V (rated voltage of a single energy storage unit), i = 2A (maximum discharge current of a single energy storage unit); System parameters: e = 0.9 (energy conversion efficiency of the system); k_cool = 0.3, k_heat = 0.4, k_standby = 0.1 (base weight values) P_cool_max = 800W, P_heat_max = 600W (maximum cooling and heating power) Calculation process: Calculate the power that the current configuration can provide: Pa = V * i * floor(V / v) = 48 * 2 * floor(48 / 3.7) = 48 * 2 * 12 =1152W Assume that the system is currently in cooling mode, cooling power P_cool = 600W k = k_cool * (1 + P_cool / P_cool_max) = 0.3 * (1 + 600 / 800) =0.525 Calculate the safety factor S: S = max(0, (Pr - Pa) / Pa + k * (1 - e)) = max(0, (1100 - 1152) / 1152 + 0.525 * (1 - 0.9)) = max(0, -0.0451 + 0.0525) = 0.0074 Calculate the total number of energy storage units N required: N = ceil(V / v) * ceil(P / (V * i)) * (1 + S) = ceil(48 / 3.7) * ceil(1000 / (48 * 2)) * (1 + 0.0074) = 13 * 11 * 1.0074 = 144.06 Round up, and finally N = 145.

[0031] The method of this embodiment takes into account the real-time working state of the system (cooling, heating or standby), and dynamically adjusts the number of energy storage units by adjusting the weight coefficient k. It ensures that the system has sufficient power supply in different working modes. By introducing the safety factor S, the difference between power demand and actual supply, as well as the influence of energy conversion efficiency, are taken into account in the calculation. It helps to prevent the system from running out of power under high load conditions. The use of an upward rounding function ensures that the number of energy storage units always meets or slightly exceeds the demand, avoiding the risk of power shortage. By considering the energy conversion efficiency e of the system, the number of energy storage units required can be estimated more accurately, avoiding waste of resources caused by over-configuration. Automatically adjust the configuration according to different working modes (cooling, heating, standby) so that the system can maintain optimal performance in all situations.

[0032] Embodiment 3: In addition, the system further includes a road condition detection unit, and the thermal management module adjusts the temperature of each functional unit according to the real-time driving road condition detected by the road condition detection unit, specifically including: When it is detected that the vehicle is in an uphill or high-speed driving state, the temperature of the key energy storage unit is actively reduced to ensure its stability under continuous high-power discharge conditions.

[0033] The road condition detection unit includes GPS, acceleration sensor and inclination sensor, which are used to monitor the vehicle's position, speed, acceleration and road slope in real time. The collected data is then transmitted to the power supply management module for processing to calculate the current real-time road condition information.

[0034] The power supply management module implements a differentiated thermal management strategy for each of the functional units based on the output of the road condition detection unit, and the strategy includes: When it is detected that the vehicle is in an uphill or high-speed driving state, the temperature of the key energy storage unit is actively lowered to ensure its stability under continuous high-power discharge conditions; the cooling temperature can be 3-5°C lower than the normal temperature, or a graded cooling strategy can be adopted to adjust the cooling intensity according to the slope or speed.

[0035] It also includes priority cooling management of the key energy storage units to cope with the rapid temperature rise during high-power discharge; the priority cooling may adopt a liquid cooling or forced air cooling system. When a high-power discharge demand is detected (such as sudden acceleration), the cooling system is started in real time and the cooling intensity is adjusted in proportion to the discharge power.

[0036] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above-mentioned implementation mode, but also include technical schemes composed of any combination of the above-mentioned technical features. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

1. A battery thermal management system, characterized in that: include: A battery pack, comprising a plurality of energy storage units with the same physical characteristics, each of the energy storage units being electrically connected to a busbar and a bidirectional DC-DC converter through a multi-channel switch, each channel of the multi-channel switch being a bidirectional switch, and the plurality of energy storage units being logically divided into a plurality of functional units; A thermal management module, including a heating / cooling module respectively arranged for each energy storage unit, for independently controlling each heating / cooling module according to a differentiated thermal management strategy; A power supply management module, electrically connected to the battery pack and the thermal management module, respectively, and used to control the adjustment of the functional units in the battery pack according to feedback information from the battery pack and the thermal management module; The adjustment includes: the battery pack is logically divided into at least a thermal management power supply unit and a key energy storage unit; For the energy storage unit designated as the thermal management power supply unit, the connection between the energy storage unit and the bidirectional DC-DC converter is opened through the power supply management module; For the energy storage unit designated as a key energy storage unit, the power supply management module opens the connection between the energy storage unit and the busbar.

2. The battery thermal management system according to claim 1, characterized in that: The power supply management module realizes the series-parallel configuration of multiple energy storage units by controlling the multi-channel switch and the bidirectional DC-DC converter, including: Series mode: multiple energy storage units are connected in sequence through multi-channel switches, and the total output voltage is adjusted using a bidirectional DC-DC converter; Parallel mode: Multiple energy storage units are connected in parallel through multi-channel switches, and the total output current is adjusted using a bidirectional DC-DC converter.

3. The battery thermal management system according to claim 1, characterized in that: The system further includes a road condition detection unit, and the thermal management module adjusts the temperature of each functional unit according to the real-time driving road condition detected by the road condition detection unit, specifically including: When it is detected that the vehicle is in an uphill or high-speed driving state, the temperature of the key energy storage unit is actively reduced to ensure its stability under continuous high-power discharge conditions.

4. The battery thermal management system according to claim 1 or 3, characterized in that: The heating / cooling module includes a thermoelectric cooling sheet and a heating film, and the two are integrated on the same heat dissipation substrate to achieve a two-way temperature regulation function.

5. The battery thermal management system according to claim 1, characterized in that: The total number of energy storage units N required by the thermal management power supply unit is determined by the following formula: N = ceil(V / v) * ceil(P / (V * i)) * (1 + S); Where V is the required total voltage, P is the required total power, v is the rated voltage of a single energy storage unit, i is the maximum discharge current of a single energy storage unit, ceil() represents the upward rounding function, and S is the safety factor, which is calculated by the following formula: S = max(0, (Pr - Pa) / Pa + k * (1 - e)); Where Pr is the power required by the system, Pa is the power that the current configuration can provide, k is an adjustable weight coefficient ranging from 0 to 1; and e is the energy conversion efficiency of the system.

6. The battery thermal management system according to claim 5, characterized in that: The weight coefficient k is associated with the working mode of the thermal management module, specifically including: When the thermal management module is in cooling mode, k = k_cool * (1 + P_cool / P_cool_max); When the thermal management module is in heating mode, k = k_heat * (1 + P_heat / P_heat_max); When the thermal management module is in standby mode, k = k_standby; Among them, k_cool, k_heat, and k_standby are preset basic weight values, P_cool and P_heat are the current cooling and heating powers, respectively, and P_cool_max and P_heat_max are the maximum cooling and heating powers.

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