Compensation mechanism, stacked battery packaging structure and full-operating packaging force control method

Abstract

The present invention discloses a compensation mechanism, a stacked battery packaging structure and a method for controlling the packaging force under all working conditions, including a liquid storage cylinder, a piston member and a spring member; the liquid storage cylinder is provided with a liquid storage cavity matched with the piston member, and a spring cavity for accommodating the spring member is provided between the liquid storage cylinder and the piston member; by adjusting the relative distance between the piston member and the liquid storage cylinder, the distance of the spring cavity can be changed, thereby changing the force to the outside world as a whole; the present scheme uses a variable stiffness spring compensation mechanism to realize the control of the battery stack packaging force to meet the optimal packaging force required under different working conditions. When the battery stack is thermally expanded, the stiffness of the variable stiffness spring compensation mechanism becomes smaller; when the ambient temperature is low and the battery stack is coldly contracted, the stiffness of the variable stiffness spring compensation mechanism becomes larger, which can ensure the active control of the battery stack packaging force.

Description

Technical Field

[0001] The present invention relates to the field of battery packaging, in particular to a compensation mechanism, a stacked battery packaging structure and a full-operating-condition packaging force control method. Background Art

[0002] The stacked battery stack is composed of multiple single cells stacked in series, and then the internal structure is tightly encapsulated by end plates and fasteners at both ends to form a multi-level battery stack structure. Stacked battery stacks include fuel cell stacks, vanadium battery stacks and other battery stack structures.

[0003] The fuel cell system is centered on the fuel cell, and together with the fuel supply and circulation system, oxidant supply system, water heat management system, control system, etc., it forms a power generation system. The fuel supply and circulation system and oxidant supply system are responsible for providing fuel and oxidant, the water heat management system is responsible for cooling the fuel cell to ensure that it works at a suitable temperature, and the control system is responsible for accurately controlling and adjusting each component to ensure the normal operation of the drive system. It has been applied in the fields of automobiles, transportation, aviation, fixed power generation equipment, shipborne equipment, etc.

[0004] A complete fuel cell consists of insulating end plates, current collecting plates, sealing rings, carbon paper, membrane electrode, bipolar plates, etc. The end plates on both sides are fastened by steel belts or long screws, and a certain packaging force is applied to stack the internal single cells together. Load transfer, material transmission, temperature exchange and other processes occur inside the fuel cell to complete the entire electrochemical reaction.

[0005] The size of the packaging force is particularly important for the packaging of fuel cell structures. If the packaging force is too small, it is easy to cause poor sealing of the fuel cell, resulting in gas leakage, sealing failure and safety hazards. At the same time, insufficient contact pressure between internal components will lead to increased contact resistance, large ohmic loss, and reduced power generation performance; if the packaging force is too large, the porous medium-carbon paper will be severely compressed, its porosity will be reduced, and the diffusion of the reaction gas in the membrane electrode will be hindered, thereby affecting the power generation performance. In severe cases, the weak components inside the fuel cell (bipolar plates, membrane electrodes, carbon paper, etc.) will be stressed, plastic deformation will occur, and the structure will fail.

[0006] The operating environment and working conditions of the fuel cell system include several typical working conditions, including normal temperature static, high temperature operation, low temperature static, and low temperature startup. Assuming that the normal temperature static working condition of the fuel cell system is the initial working condition, when it is running at high temperature, the internal components of the core are affected by temperature, pressure, etc., causing the packaging force to increase sharply, and the thermal expansion of the components of the stack (bipolar plates, membrane electrodes, sealing rings, etc.) causes the disc springs to be compressed. The overall packaging force still increases and even reaches the upper threshold of the packaging force. The use of traditional disc springs and other linear elastic components has limited buffering effect; when static or started at low temperature, the internal components of the core (especially the sealing rings) are affected by temperature, resulting in insufficient packaging force, causing gas leakage and posing great safety hazards. Therefore, it is very important to quickly and accurately adjust the fuel cell packaging force.

[0007] At the same time, during the low-temperature startup process, since the heat dissipation at the end of the fuel cell is faster, the voltage of the single cell at the end is low, which can easily lead to the failure of the low-temperature startup of the fuel cell system.

[0008] The existing patent (CN113224345) proposes an adjustable fuel cell end plate packaging structure. The invention intends to solve the problem of insufficient pre-tightening force of the screw of the fuel cell stack through an air intake compensation device to ensure the uniformity of the end plate clamping force. Among them, the flexible inflatable bag is a key part with adjustable distance, which is installed between the end plate surface and the collector plate. Although multiple flexible inflatable bags are added, there is still an installation gap. Due to its flexible and deformable characteristics, it is easy to contact the collector plate unevenly, causing the local contact resistance of the collector plate to increase, affecting the power generation performance of the stack. Under actual operating conditions (especially vehicle-mounted), the fuel cell must be fixedly installed on the bottom plate of the fuel cell system to prevent the fuel cell from moving and affecting the safe operation of the fuel cell system. Because the fuel cell end plate must be fixed to the floor, the disc spring structure will not accurately respond to changes in the internal packaging force of the stack, and thus the response of the air intake compensation mechanism is limited. Summary of the invention

[0009] The purpose of the present invention is to provide a compensation mechanism, a stacked battery packaging structure and a full-operating condition packaging force control method to address the above-mentioned problems, thereby solving the problems in the prior art that large or large-area stacked batteries are prone to uneven force and plane warping due to their large area, and at the same time solving the problem that the internal structure of the stacked battery is forced to change due to temperature changes under different operating conditions, thereby affecting the power generation performance.

[0010] The present invention is achieved through the following scheme:

[0011] A compensation mechanism comprises a liquid storage cylinder, a piston member and a spring member; the liquid storage cylinder is provided with a liquid storage cavity cooperating with the piston member, and a spring cavity for accommodating the spring member is provided between the liquid storage cylinder and the piston member; by adjusting the relative distance between the piston member and the liquid storage cylinder, the distance of the spring cavity can be changed, thereby changing the force on the outside world as a whole.

[0012] Based on the above-mentioned compensation mechanism, the liquid storage cylinder includes a first contact plate, a liquid inlet pipeline and a piston port; the first contact plate is arranged on the liquid storage chamber, the liquid inlet pipeline passes through the first contact plate and is connected to the liquid storage chamber, the piston port is arranged at the bottom of the liquid storage chamber, and the size of the piston port is matched with the contact part of the piston member, so that the piston member can move freely through the piston port.

[0013] Based on the above-mentioned compensation mechanism, the piston member includes a sealing plate, a piston rod and a second contact plate; the sealing plate is arranged in the liquid storage chamber, the size of the sealing plate is adapted to the inner diameter of the liquid storage chamber, and the sealing plate can move back and forth along the length direction of the liquid storage chamber under force; the piston rod is connected to the sealing plate and the second contact plate, and a central pipeline connecting the sealing plate and the second contact plate is arranged in the piston rod, and a liquid outlet pipeline connected to the central pipeline is arranged on the second contact plate.

[0014] Based on the above compensation mechanism, a liquid inlet regulating valve and a pressure sensor are arranged on the liquid inlet pipeline, a liquid outlet regulating valve is arranged on the liquid outlet pipeline, and a displacement sensor for detecting the relative distance between the first contact plate or the second contact plate is arranged.

[0015] Based on the above-mentioned compensation mechanism, a heater, a cooling circulation loop and a power source are also provided; the heater, the cooling circulation loop and the power source are arranged in series, and the outlet end of the power source is connected to the liquid inlet pipeline, and the outlet end of the power source is connected to the liquid outlet pipeline.

[0016] The present invention provides a packaging structure for a stacked battery stack, comprising a cathode end plate, a cathode insulating end plate, a cathode current collecting plate, a battery stack core, a packaging component, an anode current collecting plate and an anode insulating end plate; the cathode current collecting plate, the battery stack core and the anode collecting plate are respectively arranged in the area between the cathode insulating end plate and the anode insulating end plate, the cathode end plate is arranged on the end surface of the cathode insulating end plate away from the anode insulating end plate, the packaging component is arranged between the cathode end plate and the anode insulating end plate, and the packaging component performs forced limiting packaging on the overall battery structure formed by the cathode current collecting plate, the battery stack core and the anode collecting plate; and also includes a compensation mechanism, which is arranged between the cathode end plate and the cathode insulating end plate, and is arranged in multiple numbers along the length direction of the cathode current collecting plate.

[0017] The cathode end plate is provided with a through hole for the liquid inlet pipeline to pass through.

[0018] The present invention also provides a method for controlling the packaging force of a stacked battery packaging structure under all working conditions, which controls the packaging force of the stacked battery packaging structure, and specifically includes the following steps:

[0019] Step 1: Preset the packaging force F required to achieve the best power generation performance under different operating conditions X；

[0020] Step 2: Determine the state of the stacked battery packaging structure and select the corresponding F X value;

[0021] Step 3, reading the pressure sensor parameters and displacement sensor parameters in the state of step 2;

[0022] Step 4: Calculate the actual packaging force F based on the data in step 3 a , F a With F X Compare and determine F a Whether the packaging force meets the requirements, if it does, the system maintains the packaging force, if it does not meet the requirements, the compensation mechanism is used to adjust the F a The packaging force meets the requirements.

[0023] In step 4, the compensation mechanism is used to adjust F a The steps to meet the requirements of the packaging force are as follows: the packaging force F required for the best power generation performance under the preset current conditions X , the number of compensation mechanisms, the real-time values ​​detected by the displacement sensor and the real-time values ​​of the pressure sensor, dynamically adjust the liquid filling or releasing in the piston assembly, so that the actual overall structural force of the packaging structure approaches the packaging force F X .

[0024] When the fuel cell system is started and operated at room temperature or high temperature, due to the electrochemical reaction of hydrogen and oxygen in the fuel cell stack core, electrical energy and heat energy are generated, the fuel cell stack core components expand thermally, and the fuel cell stack packaging force increases; if the current packaging force is greater than the required packaging force, the displacement sensor distance becomes smaller, at this time the liquid outlet regulating valve opens, the liquid inlet regulating valve closes, due to the internal and external pressure difference, the liquid in the compensation mechanism flows out to reach the required packaging force of the fuel cell, the liquid outlet regulating valve closes, and the compensation mechanisms of other groups are controlled simultaneously according to the above method, so that the overall packaging force reaches the preset value of the packaging force required for the best power generation performance;

[0025] When the fuel cell system is stored or started at low temperature, due to the low ambient temperature, the core assembly is in a cold shrinkage state, or the rubber ring is in stress relaxation and other conditions, the stack packaging force is lower than that when it leaves the factory. If the current packaging force is less than the required packaging force, the displacement sensor distance becomes larger and changes. At this time, the liquid outlet regulating valve is closed, the liquid inlet regulating valve is opened, and the water pump branch liquid enters the compensation mechanism. When the packaging force required by the fuel cell is reached, the liquid inlet regulating valve is closed, and the liquid pressure of the compensation mechanism changes; when the inlet pressure is insufficient, consider increasing the water pump speed; during low-temperature cold start, the water pump liquid is cooled by the heater or the stack, and the liquid temperature rises and flows into the hydraulic variable stiffness spring active compensation mechanism. While increasing the stiffness, the fuel cell end is heated up, which is conducive to the low-temperature rapid start of the fuel cell. The compensation mechanisms of other groups are controlled simultaneously according to the above method, so that the overall packaging force reaches the preset value of the packaging force required for the best power generation performance.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] 1. This solution uses a variable stiffness spring compensation mechanism to control the battery stack packaging force to meet the optimal packaging force required under different working conditions. When the battery stack expands internally due to heat, the variable stiffness spring compensation mechanism becomes smaller; when the ambient temperature is low and the battery stack shrinks internally due to cold working conditions, the variable stiffness spring compensation mechanism becomes larger, which can ensure active control of the battery stack packaging force.

[0028] 2. For large or large-area stacked batteries, this solution is prone to uneven force and plane warping due to their large area. The variable stiffness spring active compensation mechanism can control and finely adjust the packaging force in different areas, which can solve the problem of uneven force or plane warping in the plane of large battery structures.

[0029] 3. When the pressure of this scheme comes from the water pump of the fuel cell system, during low-temperature cold start, the water pump liquid is cooled and heat exchanged by the heater or the stack, and the liquid temperature rises and flows into the variable stiffness spring active compensation mechanism, which increases the stiffness and can increase the temperature of the fuel cell end, which is beneficial to the low-temperature rapid start of the fuel cell.

[0030] 4. The fuel cell packaging force formed by this solution is stably and accurately controlled, which can improve the stability of the battery's power generation performance and extend the operating life of the fuel cell stack.

[0031] 5. The principle of the compensation mechanism in this scheme is simple, not restricted by material properties, and has strong machinability and feasibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the compensation mechanism in the present invention;

[0033] Figure 2It is a three-dimensional structural schematic diagram of the compensation mechanism in the present invention;

[0034] Figures 3-4 It is a structural schematic diagram of the packaging structure of the stacked battery stack of the present invention;

[0035] Description of the drawings: 1. Liquid storage cylinder; 2. Piston member; 3. Spring member; 4. Heater; 5. Cooling circulation loop; 6. Power source; 7. Cathode end plate; 8. Cathode insulating end plate; 9. Cathode current collecting plate; 10. Fuel cell core; 11. Packaging member; 12. Anode current collecting plate; 13. Anode insulating end plate; 14. Fluid; 101. Liquid storage chamber; 102. Spring chamber; 103. First resistance plate; 104. Liquid inlet pipeline; 105. Piston mouth; 106. Liquid inlet regulating valve; 107. Pressure sensor; 201. Sealing plate; 202. Piston rod; 203. Second resistance plate; 204. Center pipeline; 205. Liquid outlet pipeline; 206. Liquid outlet regulating valve; 207. Displacement sensor. DETAILED DESCRIPTION

[0036] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0037] Any feature disclosed in this specification (including any additional claims and abstract), unless otherwise stated, may be replaced by other equivalent or alternative features having similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0038] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0039] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.

[0040] Example 1

[0041] like Figure 1 As shown, the present invention provides a technical solution:

[0042] A compensation mechanism, which at least includes but is not limited to a liquid storage cylinder 1, a piston member 2 and a spring member 3; a liquid storage chamber 101 cooperating with the piston member 2 is provided in the liquid storage cylinder 1, and a spring chamber 102 for accommodating the spring member 3 is provided between the liquid storage cylinder 1 and the piston member 2; by adjusting the relative distance between the piston member 2 and the liquid storage cylinder, the distance of the spring chamber 102 can be changed, thereby changing the overall force on the outside world.

[0043] Based on the above structure, the liquid storage chamber 101 and the piston member 2 form a piston structure. By changing the distance between the inner wall of the liquid storage chamber 101 and the end of the piston member 2, the length of the spring chamber 102 can be adjusted, thereby adjusting the overall force to the outside world. The overall support force to the outside world is the sum of the elastic force of the spring and the pressure of the fluid 14 in the liquid storage chamber 101. The spring chamber 102 can also automatically reset when the external pressure becomes smaller.

[0044] As an example, the liquid storage cylinder 1 may include a first contact plate 103, a liquid inlet pipeline 104 and a piston port 105; the first contact plate 103 is arranged on the liquid storage chamber 101, the liquid inlet pipeline 104 passes through the first contact plate 103 and is connected to the liquid storage chamber 101, the piston port 105 is arranged at the bottom of the liquid storage chamber 101, and the size of the piston port 105 is matched with the contact part of the piston member 2, so that the piston member 2 can move freely through the piston port 105.

[0045] The size of the first abutment plate 103 is larger than that of the liquid storage chamber 101 , so that the first abutment plate 103 protrudes from the annular surface of the liquid storage chamber 101 and contacts the spring member 3 , providing an end limit for the spring member 3 , and the spring member 3 is sleeved on the outer wall of the liquid storage chamber 101 .

[0046] Based on the above structure, the fluid 14 can be provided to the liquid storage chamber 101 through the liquid inlet pipeline 104 to change the position of the piston member 2 in the liquid storage chamber 101, thereby adjusting the distance between the piston member 2 and the liquid storage cylinder 1.

[0047] As an example, the piston member 2 may include a sealing plate 201, a piston rod 202, and a second contact plate 203; the sealing plate is disposed in the liquid storage chamber 101, and the size of the sealing plate 201 is adapted to the inner diameter of the liquid storage chamber 101, so that the sealing plate 201 and the liquid storage chamber 101 form a sealing structure, and the sealing plate 201 can move back and forth along the length direction of the liquid storage chamber 101 under force;

[0048] The piston rod 202 is connected to the sealing plate 201 and the second contact plate 203 . A central pipeline 204 connecting the sealing plate 201 and the second contact plate is provided in the piston rod 202 . A liquid outlet pipeline 205 connecting the central pipeline 204 is provided on the second contact plate.

[0049] A flexible sealing medium may be provided on the sealing plate, and the sealing is achieved by contacting the flexible sealing medium with the liquid storage cavity.

[0050] Based on the above structure, the second resistance plate 203 provides a resistance surface for the other end of the spring member 3, and cooperates with the first resistance plate 103 to limit the spring member 3, ensuring that the spring member 3 can be adjusted in a controlled manner. The total amount of fluid 14 in the liquid storage chamber 101 can be adjusted through the liquid inlet pipeline 104 and the liquid outlet pipeline 205, thereby achieving adjustment of the supporting force of the piston member 2.

[0051] As an example, a liquid inlet regulating valve 106 and a pressure sensor 107 may be provided on the liquid inlet pipeline 104, a liquid outlet regulating valve 206 may be provided on the liquid outlet pipeline 205, and a displacement sensor 207 for detecting the relative distance between the first contact plate or the second contact plate may be provided.

[0052] Based on the above structure, the on-off of the entire fluid 14 circuit can be switched on and off through the liquid inlet regulating valve 106 and the liquid outlet regulating valve 206. The pressure sensor 107 is used to detect the pressure of the fluid 14 between the liquid inlet pipeline 104 and the liquid outlet pipeline to facilitate subsequent adjustment operations. The displacement sensor 207 is used to detect the distance value between the first resistance plate and the second resistance plate.

[0053] As an example, a heater 4, a cooling circulation loop 5, and a power source 6 may be provided outside the compensation mechanism; the heater 4, the cooling circulation loop 5, and the power source 6 are arranged in series, and the outlet end of the power source 6 is connected to the liquid inlet pipeline 104, and the inlet end of the power source 6 is connected to the liquid outlet pipeline.

[0054] Based on the above structure, the fluid 14 entering the compensation mechanism is heated by the heater 4 and the cooling circulation loop 5 to meet the working conditions under different adjustments.

[0055] As an example, the pressure medium in the compensation mechanism may be liquid or gas. The power source 6 may be a water pump or an air compressor.

[0056] Through the compensation mechanism, by actively controlling the piston assembly formed by the liquid storage cylinder 1 and the piston member 2, the external pressure of the compensation mechanism can be dynamically adjusted to increase or decrease the external pressure of the compensation mechanism. The pressure of the compensation mechanism on the outside is the elastic force of the spring member 3 and the supporting force of the piston assembly. In this solution, the structural force of the overall compensation assembly is adjusted by controlling the piston assembly.

[0057] Example 2

[0058] like Figures 2 to 4 As shown, the present invention provides a technical solution:

[0059] A packaging structure for a stacked battery stack, which at least includes but is not limited to a cathode terminal plate 7, a cathode insulating end plate 8, a cathode current collecting plate 9, a battery stack core 10, a packaging component 11, an anode current collecting plate 12, an anode insulating end plate 13 and a compensation mechanism; wherein the cathode current collecting plate 9, the battery stack core 10 and the anode collecting plate 12 are respectively arranged in the area between the cathode insulating end plate 8 and the anode insulating end plate 13, the cathode terminal plate 7 is arranged on the end surface of the cathode insulating end plate 8 away from the anode insulating end plate 13, the packaging component 11 is arranged between the cathode insulating end plate 8 and the anode insulating end plate 13, and the packaging component 11 performs forced limiting packaging on the overall battery structure formed by the cathode current collecting plate 9, the battery stack core 10 and the anode collecting plate 12.

[0060] The compensation mechanism is arranged between the cathode end plate 7 and the cathode insulating end plate 8 , and is arranged in plurality along the length direction of the cathode current collecting plate 9 .

[0061] A through hole for the liquid inlet pipeline 104 to penetrate is arranged on the cathode end plate 7 to ensure that the fluid 14 can smoothly enter the compensation component.

[0062] As an example, the packaging member 11 may be a fastening device such as a steel belt or a screw.

[0063] In this embodiment, four groups of compensation mechanisms are evenly distributed and installed between the cathode end plate 7 and the cathode insulating end plate 8, the inner surface of the cathode end plate 7 contacts the first contact plate 103 of the compensation mechanism, and the outer surface of the cathode insulating end plate 8 contacts the second contact plate 203 of the compensation mechanism. The liquid inlet pipeline 104 of the compensation mechanism passes through the cathode end plate 7 and is led out.

[0064] The liquid inlet pipeline 104 of the compensation mechanism is connected to the liquid inlet regulating valve 106, and the other end of the liquid inlet regulating valve 106 is connected to a branch of the water pump outlet. The pressure sensor 107 is installed on the liquid inlet pipeline 104 to monitor the liquid pressure of the compensation mechanism; the liquid outlet pipeline is connected to the liquid outlet regulating valve 206, and the other end of the liquid outlet regulating valve 206 is connected to the water replenishment tank of the fuel cell system (or other lowest pressure position).

[0065] In this scheme, the initial assembly state of the fuel cell is the variable stiffness spring action state, at which time the compensation hydraulic structure pressure is the optimal value. The hydraulic spring compensation mechanism is actively controlled according to the core pressure change during the operation of the fuel cell system; the system water pump parameters and the inlet and outlet stop valves of the hydraulic compensation mechanism are adjusted according to the pressure results. If the core packaging force increases, the inlet regulating valve of the compensation mechanism is closed, the outlet regulating valve is opened, and the stack packaging force is reduced to the optimal value; if the core packaging force decreases, the inlet regulating valve of the compensation mechanism is opened, the outlet regulating valve is closed, and the stack packaging force is increased to the optimal value.

[0066] This solution can dynamically adjust the packaging force of the packaged stacked battery stack, and use a variable stiffness spring compensation mechanism to control the battery stack packaging force to meet the packaging force required under different working conditions. When the battery stack expands internally due to heat, the variable stiffness spring compensation mechanism becomes smaller; when the ambient temperature is low and the battery stack shrinks internally, the variable stiffness spring compensation mechanism becomes larger, and at the same time, the end temperature is increased to facilitate the low-temperature rapid start-up of the fuel cell, thereby ensuring accurate control of the packaging force of the fuel cell under all working conditions and improving the power generation performance of the battery stack.

[0067] Example 3

[0068] The present invention provides a technical solution:

[0069] A method for controlling the full-operating-condition packaging force of a stacked battery packaging structure controls the packaging force of the stacked battery packaging structure of Example 2, which specifically comprises the following steps:

[0070] Step 1: Preset the packaging force F required to achieve the best power generation performance under different operating conditions X , the packaging force F required for the best power generation performance at each operating point X is different, such as in normal temperature start, high temperature start, low temperature cold start, etc. X The values ​​are not the same.

[0071] Step 2: Determine the state of the stacked battery packaging structure and select the corresponding F X value.

[0072] Step three, reading the parameters of the pressure sensor 107 and the displacement sensor 207 in the state in step two.

[0073] Step 4: Calculate the actual packaging force F based on the data in step 3 a , F a With F X Compare and determine F a Whether the packaging force meets the requirements, if it does, the system maintains the packaging force, if it does not meet the requirements, the compensation mechanism is used to adjust the F a The packaging force meets the requirements.

[0074] Adjust F through the compensation mechanism a The steps to meet the requirements of the packaging force are as follows: the packaging force F required for the best power generation performance under the preset current conditions X , the number of compensation mechanisms, the real-time values ​​detected by the displacement sensor and the real-time values ​​of the pressure sensor, dynamically adjust the liquid filling or releasing in the piston assembly, so that the actual overall structural force of the packaging structure approaches the packaging force F X .

[0075] When the fuel cell is assembled, the compensation mechanism contains liquid, the liquid inlet pipeline 104 and the liquid outlet pipeline are closed, and the package 11 is in a compressed state due to the pre-tightening force. A According to the principle of force interaction, the stack packaging force F A Equal to the resultant force F of all compensation mechanisms B , that is, F A =F B .

[0076] F B =ΣF Bi (i=1,2,3,4),F B1 Represents the pressure of the first set of compensation mechanisms, and so on.

[0077] F B1 Including spring force F B11 and hydraulic pressure F B12 , where the spring force F B11 = = K * X, K represents the spring stiffness, X represents the distance the free length spring is compressed; hydraulic pressure F B12 =P*A, P represents the liquid pressure, A represents the effective area of ​​the piston, and so on.

[0078] Then, F B1 =F B11 +F B12 =K*X+P*A.

[0079] Therefore, the compensation mechanism is used to adjust F a The steps to meet the requirements of the packaging force are as follows: the packaging force F required for the best power generation performance under the preset current conditions X , the number of compensation mechanisms, and the value detected by the displacement sensor 207 at this time, the required pressure value can be calculated, and the pressure difference can be obtained by comparing the calculated pressure value with the actual measured value of the pressure sensor 107. The liquid in the piston assembly is filled or released according to the positive and negative pressure differences.

[0080] When the fuel cell system is started and operated at room temperature or high temperature, due to the electrochemical reaction between hydrogen and oxygen in the stack core 10, electrical energy and heat energy are generated, and the components of the stack core 10 (bipolar plates, membrane electrodes, sealing rings, etc.) are thermally expanded, the stack packaging force increases, and the spring continues to be compressed; when operating at a certain operating point, if the current packaging force is greater than the required packaging force, the liquid outlet regulating valve 206 is opened and the liquid inlet regulating valve 106 is closed. Due to the internal and external pressure difference, the liquid in the compensation mechanism flows out until a certain moment, the distance of the displacement sensor 207 becomes smaller, changing Δx, and the liquid pressure of the hydraulic spring compensation mechanism changes Δp. When the required packaging force of the fuel cell is reached, F B1｀ , the liquid outlet regulating valve 206 is closed.

[0081] At this time, F B1｀ =F B11｀ +F B12｀ =K*(X+Δx)+(P-Δp)*A, the compensation mechanisms of other groups are controlled simultaneously according to the above method, so that the overall packaging force reaches the packaging force F required for the optimal power generation performance of the preset value. X .

[0082] When the fuel cell system is stored at low temperature or started up, due to the low ambient temperature, the core components (bipolar plates, membrane electrodes, sealing rings, etc.) are in a cold shrinkage state, or the rubber ring is in other states such as stress relaxation, the stack packaging force is lower than that when it leaves the factory, the stack packaging force is reduced, and the spring is released and stretched. When operating at a certain operating point, if the current packaging force is less than the required packaging force, the liquid outlet regulating valve 206 is closed, the liquid inlet regulating valve 106 is opened, and the water pump branches the liquid into the compensation mechanism until a certain moment, the distance of the displacement sensor 207 increases, changes Δx, and the liquid pressure of the hydraulic spring compensation mechanism changes Δp. When the required packaging force of the fuel cell is reached, F B1｀ , the liquid inlet regulating valve 106 is closed. When the inlet pressure is insufficient, the water pump speed can be increased; during low-temperature cold start, the water pump liquid is heated by the heater 4 or the stack internal cooling heat exchange, and flows into the hydraulic variable stiffness spring active compensation mechanism, which increases the stiffness and can increase the temperature of the fuel cell end, which is conducive to the low-temperature rapid start of the fuel cell.

[0083] At this time, F B1｀ =F B11｀ +F B12｀ =K*(X-Δx)+(P+Δp)*A, the compensation mechanisms of other groups are controlled simultaneously according to the above method, so that the overall packaging force reaches the packaging force F required for the optimal power generation performance of the preset value. X .

[0084] This method uses a variable stiffness spring compensation mechanism to control the battery stack packaging force to meet the optimal packaging force required under different working conditions. When the battery stack expands internally due to heat, the variable stiffness spring compensation mechanism becomes smaller; when the ambient temperature is low and the battery stack contracts internally due to cold, the variable stiffness spring compensation mechanism becomes larger, which can ensure active control of the battery stack packaging force.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A compensation mechanism, characterized in that: It comprises a liquid storage cylinder, a piston member and a spring member; a liquid storage cavity cooperating with the piston member is arranged in the liquid storage cylinder, and a spring cavity for accommodating the spring member is arranged between the liquid storage cylinder and the piston member; by adjusting the relative distance between the piston member and the liquid storage cylinder, the distance of the spring cavity can be changed, thereby changing the force to the outside world as a whole; the liquid storage cylinder comprises a first contact plate, a liquid inlet pipeline and a piston port; the first contact plate is arranged on the liquid storage cavity, the liquid inlet pipeline passes through the first contact plate and is connected to the liquid storage cavity, the piston port is arranged at the bottom of the liquid storage cavity, and the size of the piston port is matched with the contact part of the piston member, so that the piston member can move freely through the piston port; Also included is a full-operating-condition packaging force control method for a stacked battery packaging structure; It specifically includes the following steps: Step 1: Preset the packaging force F required to achieve the best power generation performance under different operating conditions X； Step 2: Determine the state of the stacked battery packaging structure during operation and select the corresponding F X value; Step 3, reading the pressure sensor parameters and displacement sensor parameters in the state of step 2; Step 4: Calculate the actual packaging force F based on the data in step 3 a , F a With F X Compare and determine F a Whether the packaging force meets the requirements, if it does, the system maintains the packaging force, if it does not meet the requirements, the compensation mechanism is used to adjust the F a The packaging force meets the requirements; the compensation mechanism is used to adjust F a The steps to meet the requirements of the packaging force are as follows: the packaging force F required for the best power generation performance under the preset current conditions X , the number of compensation mechanisms, the real-time values ​​detected by the displacement sensor and the real-time values ​​of the pressure sensor, dynamically adjust the liquid filling or releasing in the piston assembly, so that the actual overall structural force of the packaging structure approaches the packaging force F X ; When the fuel cell system is started and operated at room temperature or high temperature, due to the electrochemical reaction of hydrogen and oxygen in the fuel cell stack core, electrical energy and heat energy are generated, the fuel cell stack core components expand thermally, and the fuel cell stack packaging force increases; if the current packaging force is greater than the required packaging force, the displacement sensor distance becomes smaller, at this time the liquid outlet regulating valve opens, the liquid inlet regulating valve closes, due to the internal and external pressure difference, the liquid in the compensation mechanism flows out to reach the required packaging force of the fuel cell, the liquid outlet regulating valve closes, and the compensation mechanisms of other groups are controlled simultaneously according to the above method, so that the overall packaging force reaches the preset value of the packaging force required for the best power generation performance; When the fuel cell system is stored or started up at low temperature, the core assembly shrinks or the rubber ring relaxes due to the low ambient temperature, and the stack packaging force is lower than when it leaves the factory. If the current packaging force is less than the required packaging force, the displacement sensor distance increases, and the liquid outlet regulating valve closes, the liquid inlet regulating valve opens, and the water pump branches the liquid into the compensation mechanism. When the required packaging force for the fuel cell is reached, the liquid inlet regulating valve closes, and the liquid pressure of the compensation mechanism changes. When the inlet pressure is insufficient, consider increasing the water pump speed. During low-temperature cold start, the water pump liquid is cooled by the heater or the stack, and the liquid temperature rises, and flows into the hydraulic variable stiffness spring active compensation mechanism, which increases the stiffness and heats up the end of the fuel cell, which is beneficial to the low-temperature rapid start of the fuel cell. The compensation mechanisms of other groups are controlled simultaneously according to the above method, so that the overall packaging force reaches the preset value of the packaging force required for the best power generation performance.

2. A compensation mechanism according to claim 1, characterized in that: The piston member includes a sealing plate, a piston rod and a second contact plate; the sealing plate is arranged in the liquid storage chamber, the size of the sealing plate is adapted to the inner diameter of the liquid storage chamber, and the sealing plate can move back and forth along the length direction of the liquid storage chamber under force; the piston rod is connected to the sealing plate and the second contact plate, a central pipeline connecting the sealing plate and the second contact plate is arranged in the piston rod, and a liquid outlet pipeline connected to the central pipeline is arranged on the second contact plate.

3. A compensation mechanism according to claim 2, characterized in that: The liquid inlet pipeline is provided with a liquid inlet regulating valve and a pressure sensor, the liquid outlet pipeline is provided with a liquid outlet regulating valve, and the first contact plate or the second contact plate is provided with a displacement sensor for detecting the relative distance between the two.

4. A compensation mechanism according to claim 3, characterized in that: A heater, a cooling circulation loop and a power source are also provided; the heater, the cooling circulation loop and the power source are arranged in series, and the outlet end of the power source is connected to the liquid inlet pipeline, and the inlet end of the power source is connected to the liquid outlet pipeline.

5. A packaging structure of a stacked battery stack, comprising a cathode end plate, a cathode insulating end plate, a cathode current collecting plate, a battery stack core, a packaging component, an anode current collecting plate and an anode insulating end plate; the cathode current collecting plate, the battery stack core and the anode collecting plate are respectively arranged in the area between the cathode insulating end plate and the anode insulating end plate, the cathode end plate is arranged on the end surface of the cathode insulating end plate away from the anode insulating end plate, the packaging component is arranged between the cathode end plate and the anode insulating end plate, and the packaging component performs forced position limiting packaging on the overall battery structure formed by the cathode current collecting plate, the battery stack core and the anode collecting plate; characterized in that: It also includes the compensation mechanism as described in any one of claims 1 to 4, wherein the compensation mechanism is arranged between the cathode end plate and the cathode insulating end plate, and is arranged in plurality along the length direction of the cathode current collecting plate.

6. The packaging structure according to claim 5, characterized in that: The cathode end plate is provided with a through hole for the liquid inlet pipeline to pass through.

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