Thermoelectric module with intrinsic open-circuit protection function and protection method thereof

Abstract

This invention discloses a thermoelectric module with intrinsic open-circuit protection and its protection method. The thermoelectric module includes multiple thermoelectric units connected in series and at least one bidirectional protection device. The bidirectional protection device is connected in parallel with at least one of the thermoelectric units and is a semiconductor device with bidirectional avalanche breakdown characteristics. Its breakdown voltage satisfies: where is the normal operating terminal voltage of the thermoelectric unit, α is the absolute value of the Seebeck coefficient, is the maximum design temperature difference, and is the voltage across the faulty unit during an open-circuit fault. During normal operation, the protection device is high-resistance cutoff; during a fault, it avalanche conduction forms a bypass. This invention also provides an open-circuit protection method for the thermoelectric module, including a threshold determination step and a voltage triggering step. This invention achieves hardware-level passive fault tolerance, with fast response speed and high reliability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor thermoelectric technology, specifically to a thermoelectric module and its open-circuit protection method, and particularly to a thermoelectric module and protection method that can adapt to the bidirectional current and thermoelectric electromotive force characteristics of the thermoelectric module and realize distributed passive fault tolerance. Background Technology

[0002] Thermoelectric modules operate based on the Peltier effect and have advantages such as no moving parts, rapid response, and precise temperature control. They are widely used in precision temperature management in optoelectronic devices, medical equipment, high-performance computing, and other fields, and can also be used for low-grade heat recovery power generation.

[0003] In practical applications, thermoelectric modules are typically composed of multiple P-type and N-type thermoelectric units connected in series to provide sufficient operating voltage and cooling / power generation capabilities. However, this series structure has an inherent reliability vulnerability: when any thermoelectric unit experiences a physical open-circuit failure (such as solder joint detachment, material fracture, or a sharp increase in internal resistance due to thermal stress), the entire current loop will be interrupted, causing the entire series branch to fail, potentially rendering the entire module unusable. This single-point failure problem is particularly pronounced in high-power applications or high-voltage applications with multiple series connections.

[0004] In existing technologies, solutions to such problems typically employ redundant designs (such as parallel multi-channel modules) or external detection circuits to monitor faults and cut off power. However, these solutions either significantly increase cost and size or have slow response times (milliseconds or longer) and cannot maintain the module's basic functionality after a fault occurs. More importantly, thermoelectric modules operate under bidirectional current conditions (current directions are opposite in cooling and heating modes), and due to the temperature difference effect, a dynamically changing thermoelectric electromotive force is generated when the circuit is open. This makes traditional unidirectional protection devices (such as ordinary diodes) unsuitable—when the current is reversed, the unidirectional device will be in a reverse bias state and cannot conduct, thus losing its protection function. If an ordinary bidirectional TVS is used without coupling with thermoelectric material parameters, problems may arise such as false triggering during normal operation or unreliable conduction during open-circuit faults.

[0005] Therefore, there is an urgent need in the field for a thermoelectric module structure and its protection method that can automatically maintain circuit continuity when a single thermoelectric unit is open, adapt to the bidirectional current and thermoelectric electromotive force characteristics of the thermoelectric module, and require no complex control circuit. Summary of the Invention

[0006] This invention addresses the problem of overall failure of thermoelectric modules due to open circuits in a single thermoelectric unit in existing technologies. It provides a thermoelectric module with intrinsic open circuit protection and its protection method, which can automatically form a bypass path when a unit fails, maintaining the normal operation of the remaining units and significantly improving the reliability and fault tolerance of the module.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a thermoelectric module with intrinsic open-circuit protection, comprising multiple thermoelectric units connected in series, each thermoelectric unit including a P-type semiconductor leg and an N-type semiconductor leg, characterized in that:

[0009] It also includes at least one bidirectional protection device, which is connected in parallel with at least one of the thermoelectric units; the bidirectional protection device is a semiconductor device with bidirectional avalanche breakdown characteristics, used to adapt to the current direction reversal when the thermoelectric module switches between cooling and heating modes; the breakdown voltage of the bidirectional protection device... The following constraints must be satisfied:

[0010] in:

[0011] This is the terminal voltage when the thermoelectric unit is operating normally.

[0012] This represents the absolute value of the Seebeck coefficient for thermoelectric materials.

[0013] This represents the maximum temperature difference under the design operating conditions of the thermoelectric module.

[0014] This refers to the voltage formed across the faulty thermoelectric unit when an open-circuit fault occurs in the series circuit, resulting from the combined action of the remaining normally functioning thermoelectric units and the external power supply.

[0015] When the thermoelectric unit is working normally, the bidirectional protection device is in a high-resistance cutoff state;

[0016] When the thermoelectric unit experiences an open-circuit fault, the bidirectional protection device undergoes avalanche breakdown and remains conductive, forming a bypass current path.

[0017] The above Definition and determination method: In a series-connected thermoelectric module, when an open-circuit fault occurs in one of the thermoelectric units, the series circuit is interrupted. At this time, the external power supply voltage and the voltages generated by the remaining normally operating thermoelectric units (including Peltier voltage and / or Seebeck voltage) will be redistributed. Since the faulty unit exhibits a high impedance state, most of the voltage will be concentrated across the faulty unit.

[0018] The voltage It can be estimated by the following formula:

[0019]

[0020] in, This is the external power supply voltage. For the first The operating voltage of a normal thermoelectric unit. Under approximately uniform distribution conditions. , This refers to the total number of series-connected units. Those skilled in the art can adjust the number of series-connected units, unit operating voltage, and external power supply conditions accordingly. To perform calculations or measurements. It should be noted that... The precise value may fluctuate slightly due to factors such as temperature difference distribution and contact resistance, but its amplitude is significantly higher than the normal operating voltage. And much larger The design lower limit. Therefore, the above definition is sufficient to guide the selection of protection devices.

[0021] In the above inequalities This is the thermoelectric electromotive force, used to determine the upper limit of the normal operating voltage, and its function is to define the triggering range of the protection device. In thermoelectric modules, due to the Seebeck effect of thermoelectric materials, when a temperature difference exists... At this time, each thermoelectric unit will generate an additional electromotive force, the magnitude of which is This electromotive force will be superimposed on the applied operating voltage. This ensures that the actual upper limit of the thermoelectric unit's voltage under normal operating conditions is no longer [the limit]. Instead, it was elevated to:

[0022]

[0023] In a series thermoelectric module, when an open-circuit fault occurs in one thermoelectric unit, its voltage will be redistributed by the other units in the series circuit, causing the voltage across the faulty unit to rise rapidly, approximately equal to the open-circuit voltage of the entire series circuit. .

[0024] Therefore, in order to effectively distinguish between normal operating conditions and fault conditions, and to ensure that the protection device neither mis-conducts under normal operating conditions nor mis-conducts when a fault occurs, the breakdown voltage of the bidirectional protection device is... The above inequality constraints must be satisfied.

[0025] If ignored Item, based only on If a breakdown voltage is set, the actual operating voltage may exceed the set breakdown voltage under temperature difference conditions, which may cause the protection device to falsely activate under normal operating conditions.

[0026] On the other hand, if the breakdown voltage is reduced to avoid false triggering... Setting it too high, causing it to approach or exceed the open-circuit voltage. If an open-circuit fault occurs, the protection device will be unable to enter the conducting state, resulting in protection failure.

[0027] therefore, Although the term represents a voltage value in the millivolt range, its function is to serve as an upper limit offset for the normal operating voltage, rather than a simple voltage superposition term. It determines the upper limit of the normal operating voltage and is a crucial parameter that cannot be ignored in the design of protection thresholds. Only by including this term in the constraints can we ensure that the breakdown voltage of the protection device falls within the effective operating range that ensures both false triggering and reliable triggering.

[0028] For a more intuitive explanation The decisive role of the term in the design of protection thresholds is illustrated by the following typical numerical comparison example:

[0029] Suppose the normal operating terminal voltage of a thermoelectric unit Maximum thermoelectric potential The power supply voltage ripple is (Right now ).

[0030] If ignored Item: Designers may set the breakdown voltage of the protection device. Selected as slightly higher ,For example However, under maximum temperature difference conditions, the upper limit of the actual operating voltage of the thermoelectric unit is... The peak value after voltage ripple is superimposed can reach It has exceeded The breakdown threshold. At this point, the protection device will falsely activate, causing abnormal bypass of the module and system failure.

[0031] If the inequality constraint of this invention is applied: It requires... In actual selection, considering standard component specifications, the following can be chosen: The bidirectional TVS. This value is much higher than the upper limit of normal operating voltage (including ripple), while being much lower than the open-circuit fault voltage (approximately). Therefore, the protection device reliably cuts off during normal operation and reliably conducts during open-circuit faults.

[0032] The above comparison shows that, although Although it is only in the millivolt range, it defines the upper limit of the normal operating voltage. Ignoring this limit will cause the protection threshold to fall into the danger zone; incorporating this limit ensures that the protection device obtains an effective parameter range between "no false triggering" and "no failure to operate".

[0033] Preferably, the bidirectional protection device includes a bidirectional transient voltage suppressor, a bidirectional overvoltage protector, or a bidirectional avalanche structure composed of two Zener diodes connected back-to-back in series.

[0034] Furthermore, the bidirectional protection device is connected in parallel at both ends of a single thermoelectric unit or a group structure composed of multiple thermoelectric units.

[0035] Furthermore, the number of thermoelectric units in the thermoelectric unit array is configured such that when any thermoelectric unit experiences an open-circuit fault, the combined effect of the external power supply voltage and the remaining normally operating thermoelectric units can create a voltage concentration effect across the faulty unit, causing the voltage across the faulty unit to exceed the breakdown voltage, thereby triggering the bidirectional protection device to conduct.

[0036] Preferably, the thermoelectric unit array includes at least four pairs of P / N thermoelectric units.

[0037] Furthermore, the thermoelectric module also includes a hot-end substrate and a cold-end substrate, and the thermoelectric unit array is sandwiched between the hot-end substrate and the cold-end substrate; the bidirectional protection device is mounted on the hot-end substrate or the cold-end substrate and is connected in parallel with the thermoelectric unit through an electrical connection portion.

[0038] Furthermore, the thermoelectric module also includes a programmable switch matrix, which is used to dynamically switch the electrical connection mode between thermoelectric units; the bidirectional protection device is integrated with the programmable switch matrix on the same substrate or in the same package.

[0039] The present invention also provides an open-circuit protection method for a thermoelectric module, applied to the above-mentioned thermoelectric module, comprising the following steps:

[0040] Threshold determination steps: Based on the absolute value of the Seebeck coefficient of the thermoelectric unit material. Maximum design temperature difference of thermoelectric module and the normal operating terminal voltage of the thermoelectric unit Determine the breakdown voltage of the bidirectional protection device. satisfy:

[0041]

[0042] in This refers to the voltage applied across the faulty thermoelectric unit in a series circuit under open-circuit fault conditions.

[0043] Voltage triggering step: When any thermoelectric unit experiences an open-circuit fault, the voltage across the thermoelectric unit rises to exceed the breakdown voltage. The bidirectional protection device connected in parallel with it automatically undergoes avalanche breakdown and continues to conduct, forming a bypass current path.

[0044] Preferably, the method further includes a dynamic threshold adjustment step: based on the real-time temperature difference. Dynamically adjust the effective protection threshold This is to optimize protection sensitivity while ensuring no false triggering.

[0045] Preferably, when multiple thermoelectric units experience open-circuit faults one after another, each parallel protection device is turned on sequentially according to the voltage at its respective ends, forming a distributed time-sequential coordination.

[0046] Preferably, when the thermoelectric module switches between cooling mode and heating mode, causing the current direction to reverse, the bidirectional protection device still maintains bidirectional avalanche breakdown characteristics under reverse voltage and maintains the bypass function.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] 1. Intrinsic fault tolerance: By connecting bidirectional protection devices in parallel across the thermoelectric unit, when any unit is open-circuited, the protection devices automatically avalanche conduction is activated to form a bypass path, maintaining the continued operation of other units in the circuit. This achieves hardware-level passive fault tolerance without the need for software or external control intervention.

[0049] 2. Forced adaptation to bidirectional thermoelectric operation: The use of bidirectional protection devices ensures that the protection function is effective in both cooling and heating modes, solving the problem of unidirectional devices failing due to reverse bias in thermoelectric systems.

[0050] 3. Rigid coupling of parameters and thermoelectric characteristics: breakdown voltage of protection devices Must meet This inequality uses the thermoelectric material parameters (Seebeck coefficient) and the thermoelectric electromotive force αΔT formed by the temperature difference as the decisive boundary constraints, fundamentally eliminating the risk of false triggering and protection failure.

[0051] 4. Multi-unit collaborative fault tolerance: When multiple thermoelectric units experience open-circuit faults successively, each parallel protection device conducts sequentially according to its own terminal voltage, forming a distributed timing coordination. This mechanism requires no central controller, is entirely based on local voltage sensing, and achieves decentralized system-level fault tolerance.

[0052] 5. Dual-mode Adaptation: This invention is applicable to both cooling mode (dominated by the Peltier effect) and power generation mode (dominated by the Seebeck effect) under the same structure. In power generation mode, the thermoelectric electromotive force becomes the main voltage source, and this invention automatically adapts to this change through a parameter model (at this time...). The inequality degenerates into ).

[0053] 6. Flexible implementation: Bidirectional protection devices can be bidirectional transient voltage suppressors (bidirectional TVS) or bidirectional overvoltage protectors (PLED). For extremely low voltage applications, two Zener diodes can also be connected back-to-back in series, as long as the inequality constraint of breakdown voltage is met.

[0054] 7. Scalable two-layer fault-tolerant architecture: Based on the core solution of this invention, it can be further coordinated with a programmable switch matrix to form a two-layer fault-tolerant architecture of "passive hardware protection + active topology reconfiguration", which absorbs the transient spikes of the switch and provides a backup bypass when the switch device fails, thereby significantly improving the system-level reliability. Attached Figure Description

[0055] Figure 1 This is a circuit diagram of the thermoelectric module of the present invention;

[0056] Figure 2 This is a schematic diagram of a structure according to an embodiment of the present invention;

[0057] Figure 3 This is a schematic diagram showing the status of the bidirectional protection device when the thermoelectric unit is operating normally.

[0058] Figure 4 A schematic diagram showing the bidirectional protection device activating to form a bypass when the thermoelectric unit experiences an open-circuit fault;

[0059] Figure 5 This is a schematic diagram of the present invention applied to a thermoelectric module with dynamic reconfiguration function.

[0060] In the diagram: 1-Thermoelectric unit array, 11-P-type thermoelectric unit, 12-N-type thermoelectric unit, 2-Bidirectional protection device, 3-Hot end substrate, 4-Cold end substrate, 5-Electrical connection part, 6-Programmable switch matrix. Detailed Implementation

[0061] To enhance understanding of the present invention, it will be further described in detail below with reference to the accompanying drawings and specific embodiments. These embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0062] Example 1: Basic Structure and Parameter Selection Example

[0063] like Figure 1 and Figure 2 As shown, this embodiment provides a thermoelectric module with intrinsic open-circuit protection function, including a thermoelectric unit array 1 and multiple bidirectional protection devices 2.

[0064] The thermoelectric unit array 1 is composed of multiple alternating P-type thermoelectric units 11 and N-type thermoelectric units 12, with each thermoelectric unit connected in series via an electrical connection part 5. In this embodiment, the thermoelectric units use bismuth telluride (Bi2Te3)-based thermoelectric material, with a unit height of 1.5 mm and a cross-sectional area of ​​1.2 mm². The thermoelectric unit array contains 16 pairs of P / N thermoelectric units, for a total of 32 units.

[0065] The bidirectional protection device 2 is a semiconductor device with bidirectional avalanche breakdown characteristics, such as a bidirectional transient voltage suppressor (bidirectional TVS). Each bidirectional protection device 2 is connected in parallel with a thermoelectric unit, that is, the two ends of the device are respectively soldered to the electrical connection parts at both ends of the thermoelectric unit.

[0066] In this embodiment, the rated operating current of the thermoelectric module is 2A, and the terminal voltage V of a single thermoelectric unit during normal operation is... op Approximately 0.4V. This thermoelectric material operates at its maximum design temperature difference. The Seebeck coefficient α at 60℃ is approximately 200 μV / K, therefore the maximum thermoelectric potential... The sum of the normal operating terminal voltage and the maximum thermoelectric electromotive force (denoted as A) is 0.412V. The breakdown voltage of the protection device... Must meet > A and < In this embodiment, the external power supply voltage... (32 units connected in series, 0.4V per unit), voltage across the faulty unit during an open-circuit fault. The supply voltage is approximately 12.8V. Considering the voltage specifications of standard devices, this embodiment selects a bidirectional TVS with a breakdown voltage of 6.0V (such as SMBJ6.0CA). This value meets the requirements. and Under certain conditions, it can reliably conduct when an open-circuit fault occurs.

[0067] It should be noted that, since the breakdown voltage of standard protection devices is a discrete value, in actual selection, it can be determined based on whether the following conditions are met. Under the premise of A, round up according to the device standard specifications. For higher operating voltages or larger temperature differences (such as... =0.55V, ΔT=70℃, α=210μV / K, then A≈0.565V), a bidirectional TVS with a breakdown voltage of 10V (such as SMBJ10CA) can be selected, which also satisfies the requirements. Condition A. For extremely low voltage applications, two Zener diodes connected back-to-back in series can be used to form a bidirectional protection device. By selecting a Zener diode with a suitable breakdown voltage, the above inequality can also be satisfied. Those skilled in the art can select a suitable protection device according to the above inequality constraints based on specific operating parameters.

[0068] like Figure 3 As shown, when all thermoelectric units are working normally, the bidirectional protection device 2 is in a high-resistance cutoff state, and the current I flows through the thermoelectric unit. The protection device only bears the reverse bias voltage, the leakage current is less than μA, and the power consumption is negligible.

[0069] like Figure 4 As shown, suppose an N-type thermoelectric unit 12 experiences an open-circuit fault (e.g., solder joint detachment). The current in that branch is interrupted, causing the voltage across the unit to rapidly rise to the external power supply voltage level (approximately 12.8V). When the voltage reaches the avalanche breakdown voltage of the bidirectional protection device 2 (6.0V), the device instantaneously conducts (response time on the order of nanoseconds), forming a low-resistance bypass path. At this time, the current I bypasses the damaged thermoelectric unit and continues to flow to the next unit through the bidirectional protection device 2, maintaining the conduction of the entire series branch. Other intact thermoelectric units continue to operate normally, and the module's cooling capacity is only reduced by about 1 / 32 (approximately 3%), rather than completely failing.

[0070] Example 2: Preferred protection method (including dynamic threshold adjustment and multi-unit collaboration)

[0071] This embodiment describes a preferred implementation of the present invention, which includes optional optimization steps such as dynamic threshold adjustment and multi-unit collaboration. The core method protected by the claims only includes two necessary steps: threshold determination and voltage triggering.

[0072] Take a thermoelectric module containing 32 thermoelectric units (16 pairs) as an example:

[0073] Step A (parameter constraints): Based on the absolute value of the Seebeck coefficient of the thermoelectric material Maximum design temperature difference Single unit normal operating terminal voltage Determine the breakdown voltage of the bidirectional protection device. Must meet ,and .

[0074] Step B (Device Configuration): Under the premise of satisfying the above inequalities, and considering the voltage specifications of standard devices, a bidirectional TVS with a breakdown voltage of 6.0V is selected and connected in parallel with each thermoelectric unit.

[0075] Step C (Real-time Temperature Difference Monitoring and Dynamic Threshold Adjustment): During module operation, the real-time temperature difference is acquired through a temperature sensor. And adjust the effective protection threshold dynamically accordingly: For example, when hour, This adjustment optimizes protection sensitivity while ensuring no false triggering.

[0076] Step D (Fault Triggering and Bypass): When an open-circuit fault occurs in a thermoelectric unit, the voltage across its terminals rises rapidly to exceed the current effective protection threshold. The bidirectional TVS connected in parallel with the unit automatically avalanche breakdowns and conducts, forming a bypass path.

[0077] Step E (Multi-unit Coordination): If multiple units experience open-circuit faults sequentially, each parallel protection device will turn on in turn according to the voltage across its respective terminals. After the first protection device turns on, voltage redistribution may further increase the voltage of other faulty units, accelerating the turn-on of their protection devices and achieving distributed timing coordination.

[0078] Step F (Bidirectional Adaptation): When the module switches between cooling and heating modes, the current direction is reversed. The bidirectional TVS maintains the same avalanche breakdown characteristics under reverse voltage, ensuring consistent protection functions.

[0079] Example 3: Thermo-electric coupling mechanism and multi-unit synergy

[0080] This embodiment is used to illustrate the nonlinear characteristics of voltage distribution in the open-circuit state of the thermoelectric module and the multi-unit collaborative protection mechanism.

[0081] When a thermoelectric module consists of N thermoelectric units connected in series, the voltage distribution across each unit is basically uniform under steady-state operating conditions. However, when an open-circuit fault occurs in a thermoelectric unit (e.g., the j-th unit), the impedance across that unit increases sharply, and the external power supply voltage is redistributed. Due to the Seebeck effect in thermoelectric materials, a back electromotive force related to the temperature difference exists simultaneously across each unit, causing the voltage distribution to exhibit nonlinear characteristics. Experiments show that within a very short time after an open-circuit fault occurs, the voltage across the faulty unit can reach several times or even tens of times its normal value, while the voltage of adjacent units decreases accordingly.

[0082] The bidirectional protection device of this invention is connected in parallel across each thermoelectric unit. When the voltage of a faulty unit reaches its breakdown threshold, the device conducts, forming a bypass. At this time, due to the existence of the bypass, the voltage originally concentrated in the faulty unit is clamped, and the voltage of adjacent units returns to the normal range. Furthermore, if multiple units experience open-circuit faults simultaneously or sequentially, each parallel protection device will conduct sequentially according to the voltage across its respective terminals, forming a multi-bypass coordination to ensure that the entire series circuit remains conductive at all times. This multi-unit coordinated protection mechanism requires no central controller, is entirely based on local voltage sensing, and achieves distributed fault tolerance.

[0083] Example 4: Extended Example of Collaboration with Programmable Switch Matrix

[0084] like Figure 5 As shown in the figure, this embodiment demonstrates an extended architecture in which the bidirectional protection device and the programmable switch matrix of the present invention work together.

[0085] In addition to the thermoelectric unit array 1 and the bidirectional protection device 2, the thermoelectric module is also equipped with a programmable switch matrix 6. The programmable switch matrix 6 consists of multiple switching devices and is used to dynamically switch the electrical connection mode between thermoelectric units, realizing flexible configuration of the number of series stages and parallel groups, thereby adapting to application scenarios with different voltage / current requirements.

[0086] The bidirectional protection device 2 and the programmable switch matrix 6 produce the following synergistic effect:

[0087] (1) Transient protection of switches: At the moment when the programmable switch matrix 6 performs topology switching, even if a soft switching strategy is adopted, voltage spikes may still be generated in the circuit. During this process, the bidirectional protection device 2 automatically absorbs the voltage spikes and clamps the voltage within a safe range, protecting the switching devices and thermoelectric units from damage caused by transient overvoltage.

[0088] (2) Switch failure backup protection: When a switch device in the programmable switch matrix 6 experiences an open circuit fault, the bidirectional protection device 2 connected in parallel with the branch where the switch device is located can provide bypass protection to avoid the failure of the whole machine due to a single switch failure.

[0089] (3) Fault isolation and reconfiguration coordination: When an open circuit fault occurs in a thermoelectric unit, after the bidirectional protection device 2 connected in parallel is turned on to form a bypass, the programmable switch matrix 6 can further respond, adjust the topology, isolate the branch where the fault unit is located as a whole, optimize the utilization rate of the remaining intact units, and realize the dual-layer fault tolerance of "passive protection" and "active reconfiguration".

[0090] In this embodiment, the bidirectional protection device 2 and the programmable switch matrix 6 are integrated on the same substrate and electrically connected through internal leads to form a highly integrated intelligent thermoelectric module.

[0091] Example 5: Dual-mode adaptive (cooling / power generation)

[0092] This embodiment is used to illustrate the adaptive characteristics of the present invention in cooling mode and power generation mode.

[0093] In cooling mode, the thermoelectric module is powered by an external power source, and the current flows from the P-type to the N-type (Peltier effect). The operating voltage of each thermoelectric unit is mainly determined by the power supply voltage, with the thermoelectric electromotive force as a secondary factor.

[0094] In power generation mode, the thermoelectric module functions as a generator, requiring no external power source. The current is driven by the temperature difference (Seebeck effect), and the voltage across each thermoelectric unit is entirely determined by the thermoelectric electromotive force. In this mode, The core inequality of this invention degenerates into:

[0095] in The sum of voltages generated by the remaining normal power generation units when one thermoelectric unit is open-circuited. The breakdown voltage of the protection device remains between the upper limit of the normal operating voltage and the open-circuit voltage. Therefore, the protection device remains off during normal power generation and only conducts when an open-circuit fault occurs. Dynamic threshold adjustment also applies. This design allows the same protection structure to adapt to two completely different operating modes without any mode switching, demonstrating the versatility and inventiveness of this invention.

[0096] Example 6: Integrated Packaging Example

[0097] This embodiment provides a method for integrating bidirectional protection devices with thermoelectric modules through packaging.

[0098] During the manufacturing process of thermoelectric modules, after the thermoelectric units are soldered, the bidirectional protection device chip is directly mounted on the same substrate (hot-end substrate or cold-end substrate) and connected to the electrical connection points at both ends of the thermoelectric unit via wire bonding or solder. The protection device can be encapsulated in the edge area of ​​the module or embedded in the gap between the thermoelectric units as a bare chip.

[0099] This integration method does not increase the overall size of the module, and the protection device and the thermoelectric unit share the heat dissipation path, which simplifies thermal management. At the same time, it shortens the electrical connection path, reduces parasitic inductance, and helps to give full play to the fast response characteristics of the protection device.

[0100] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various improvements and modifications without departing from the spirit and principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A thermoelectric module with intrinsic open-circuit protection, comprising multiple thermoelectric units connected in series, each thermoelectric unit including a P-type semiconductor leg and an N-type semiconductor leg, characterized in that: It also includes at least one bidirectional protection device, which is connected in parallel with at least one of the thermoelectric units; the bidirectional protection device is a semiconductor device with bidirectional avalanche breakdown characteristics, used to adapt to the working condition of current reversal when the thermoelectric module switches between cooling mode and heating mode. The breakdown voltage of the bidirectional protection device The following constraints must be satisfied: in: This is the terminal voltage when the thermoelectric unit is operating normally. This represents the absolute value of the Seebeck coefficient for thermoelectric materials. This represents the maximum temperature difference under the design operating conditions of the thermoelectric module. This refers to the voltage formed across the faulty thermoelectric unit when an open-circuit fault occurs in the series circuit, resulting from the combined action of the remaining normally functioning thermoelectric units and the external power supply.

2. The thermoelectric module according to claim 1, characterized in that: The bidirectional protection device includes a bidirectional transient voltage suppressor, a bidirectional overvoltage protector, or a bidirectional avalanche structure composed of two Zener diodes connected back-to-back in series.

3. The thermoelectric module according to claim 1, characterized in that: The bidirectional protection devices are connected in parallel at both ends of a single thermoelectric unit or a group structure consisting of multiple thermoelectric units.

4. The thermoelectric module according to claim 1, characterized in that: The number of thermoelectric units in the thermoelectric unit array is configured such that when any thermoelectric unit experiences an open-circuit fault, the combined effect of the external power supply voltage and the remaining normally operating thermoelectric units can create a voltage concentration effect across the faulty unit, causing the voltage across the faulty unit to exceed the breakdown voltage, thereby triggering the bidirectional protection device to conduct.

5. The thermoelectric module according to claim 4, characterized in that, The thermoelectric unit array includes at least 4 pairs of P / N thermoelectric units.

6. The thermoelectric module according to claim 1, characterized in that: It also includes a hot-end substrate and a cold-end substrate, with the thermoelectric unit array sandwiched between the hot-end substrate and the cold-end substrate; the bidirectional protection device is mounted on the hot-end substrate or the cold-end substrate and is connected in parallel with the thermoelectric unit through an electrical connection portion.

7. The thermoelectric module according to claim 1, characterized in that: It also includes a programmable switch matrix, which is used to dynamically switch the electrical connection mode between thermoelectric units; the bidirectional protection device is integrated with the programmable switch matrix on the same substrate or in the same package.

8. An open-circuit protection method for a thermoelectric module, applied to a thermoelectric module composed of multiple thermoelectric units connected in series, characterized in that, include: Threshold determination steps: Based on the absolute value of the Seebeck coefficient of the thermoelectric unit material. Maximum design temperature difference of thermoelectric module and the normal operating terminal voltage of the thermoelectric unit Determine the breakdown voltage of the bidirectional protection device. satisfy: in This refers to the voltage applied across the faulty thermoelectric unit in a series circuit under open-circuit fault conditions. Voltage triggering step: When any thermoelectric unit experiences an open-circuit fault, the voltage across the thermoelectric unit rises to exceed the breakdown voltage. The bidirectional protection device connected in parallel with it automatically undergoes avalanche breakdown and continues to conduct, forming a bypass current path.

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