Energy storage unit with low leakage loss

Abstract

The utility model belongs to the field of all-vanadium liquid flow energy storage units, and discloses an energy storage unit with low leakage loss. Comprising a galvanic pile in a power box, and a galvanic pile liquid inlet branch main pipeline and a galvanic pile liquid outlet branch main pipeline which are connected with the galvanic pile in the power box. After optimization, the electric power of the circulating pump of the all-vanadium redox flow battery is reduced, the efficiency of the battery system is improved, and the height of the power container is reduced by about 15% by canceling a coil pipe structure in the power container on the premise of meeting the optimal leakage loss.

Description

Technical Field

[0001] This utility model belongs to the field of vanadium redox flow energy storage units, specifically relating to a low leakage loss energy storage unit. Background Technology

[0002] Leakage loss in vanadium redox flow batteries is a significant factor affecting system efficiency. Large leakage losses can lead to localized overheating and damage in the system's piping, or the precipitation of pentavalent vanadium in the electrolyte, impacting battery performance and causing irreversible economic losses. Existing technical solutions for reducing leakage loss involve lengthening the inlet and outlet pipes of the battery stack's liquid circuit. This involves increasing the length of a relatively thin pipe segment in the battery stack's liquid circuit. The pipe resistance R is directly proportional to the pipe length L and inversely proportional to the pipe's cross-sectional area S, a relationship expressed by the formula R = ρSL, where ρ is the resistivity of the electrolyte. By increasing the pipe length L, the pipe resistance can be increased, thereby reducing leakage current and leakage loss.

[0003] The above solution can indeed effectively reduce leakage current loss, but its piping layout is limited by structure, requiring the addition of multiple smaller-diameter elbows, which increases the overall system resistance. The application of high-power battery modules requires correspondingly high flow rates, and increasing the flow rate inevitably increases the overall system resistance. The circulating pump in the battery system needs a larger output to meet the system's flow and head requirements, thus increasing the overall energy consumption loss of the system.

[0004] Since the fuel cell stack is integrated into the power container, the coil structure requires a certain amount of container height. In the application of standard containers, the height design of the fuel cell stack is limited. However, to make the fuel cell stack height the standard, a custom high-cube container is required, which increases the cost and delivery time. Utility Model Content

[0005] To overcome the shortcomings of existing technologies, this utility model provides a low leakage loss energy storage unit, which improves battery system efficiency and optimizes costs by eliminating the coil structure and increasing the length of the branch main circuit.

[0006] The above-mentioned objective of this utility model is achieved through the following technical solution: a low leakage loss energy storage unit, specifically including an electric stack in a power box and an electric stack liquid inlet branch main line and an electric stack liquid outlet branch main line connected to the electric stack in the power box.

[0007] Furthermore, DN50 is used as the main inlet and outlet branch lines of the fuel cell stack.

[0008] Furthermore, the lengths of the fuel cell stack liquid inlet branch main pipeline and the fuel cell stack liquid outlet branch main pipeline are 6.5m.

[0009] Furthermore, the fuel cell stack inlet branch main pipeline and the fuel cell stack outlet branch main pipeline adopt a straight pipe section planar laying method.

[0010] Furthermore, the battery stack is a 750kW battery module.

[0011] The advantages of this utility model compared with the prior art are:

[0012] 1. Eliminate the coil structure

[0013] The coil structure significantly impedes fluid flow, creating flow resistance. It also easily forms localized eddies at bends and other points, leading to energy loss. Eliminating the coil structure effectively removes these adverse factors, reduces energy consumption during fluid transport, and improves system efficiency.

[0014] 2. Increase the length of the main branch road.

[0015] Increasing the length and inner diameter of straight pipe sections can significantly reduce the resistance to fluid flow in pipelines. A design with entirely straight pipe sections laid in a flat plane without bends reduces leakage current loss, minimizes pressure loss, and improves system efficiency. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] Figure 1 This is a schematic diagram of an existing energy storage unit structure;

[0018] Figure 2 This is a schematic diagram of the low leakage loss energy storage unit structure of this utility model.

[0019] In the diagram: 1. DN25 straight pipe and DN25 elbow for fuel cell stack liquid inlet; 2. DN25 straight pipe and DN25 elbow for fuel cell stack liquid outlet; 3. DN50 main branch line for fuel cell stack liquid inlet; 4. DN50 main branch line for fuel cell stack liquid outlet; 5. Fuel cell stack. Detailed Implementation

[0020] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially.

[0021] Example 1

[0022] Test system #1 uses a DN25 coil structure 750KW battery module.

[0023] Test system #2 uses a DN50 branch main 750KW battery module.

[0024] Experimental conditions:

[0025] A constant power range charge-discharge test was conducted on battery modules #1 and #2 at a power of 750KW, and the following data were recorded using an energy meter:

[0026] Calculate the efficiency of battery modules #1 and #2 respectively, based on charging capacity (kWh), discharging capacity (kWh), charging self-consumption capacity (kWh), and discharging self-consumption capacity (kWh).

[0027] Efficiency = (Discharge capacity kWh - Discharge self-consumption capacity kWh) / (Charging capacity kWh + Charging self-consumption capacity kWh) * 100%

[0028] Experimental results:

[0029] Battery module #1 has an efficiency of 68.56%.

[0030] Battery module #2 has an efficiency of 69.52%.

[0031] Description of the technical solution of this utility model:

[0032] 1. Eliminate the coil structure

[0033] Specific details: For the liquid inlet and outlet pipelines of the fuel cell stack inside the power box, remove the original DN25 straight pipe with a length of 3-3.5 meters, as well as the four matching DN25 elbows.

[0034] Optimization direction: The coil structure significantly impedes fluid flow, generating flow resistance. It also easily creates localized eddies at bends and other points, leading to energy loss. Eliminating the coil structure effectively removes these adverse factors, reduces energy consumption during fluid transport, and improves system efficiency.

[0035] 2. Increase the length of the main branch road.

[0036] Operation details: Modify the main branch pipeline outside the power box. The main pipeline specification is DN50, and the length of the straight pipe section is extended to 6.5 meters, with the inner diameter of the straight pipe designed to be twice the inner diameter of the original coiled pipe structure. At the same time, a completely straight pipe section planar laying method is adopted, completely eliminating the elbow structure.

[0037] Optimization direction: Increasing the length and inner diameter of straight pipe sections can significantly reduce the resistance of fluid flow in the pipeline. A design with all-straight pipe sections laid in a flat plane without bends reduces leakage current loss, pressure loss, and improves system efficiency.

[0038] In summary, according to the design scheme of this invention, the measured benefits of the 750KW battery power module are as follows:

[0039] 1. Efficiency Improvement: The 750KW battery power module improves efficiency (including self-consumption power) by approximately 1%. After optimization, the power consumption of the vanadium redox flow battery circulation pump is reduced, thus improving the efficiency of the battery system (including self-consumption power).

[0040] 2. Cost optimization: The 750KW battery power module features a three-layer stack layout in the power box. By eliminating the coil structure in the power box, the height is reduced from 3600mm to 3000mm. Under the premise of meeting the optimal leakage loss, the height of the power container is reduced by approximately 15% by eliminating the coil structure inside the power container.

[0041] The embodiments described above are merely preferred embodiments of this utility model, and not all feasible embodiments of this utility model. For those skilled in the art, any obvious modifications made without departing from the principles and spirit of this utility model should be considered to be included within the scope of protection of the claims of this utility model.

Claims

1. A low leakage loss energy storage unit, characterized in that, This includes the fuel cell stack inside the power box, as well as the fuel cell stack liquid inlet branch main line and the fuel cell stack liquid outlet branch main line connected to the fuel cell stack inside the power box.

2. The low leakage loss energy storage unit according to claim 1, characterized in that, Use DN50 as the main inlet and outlet branch lines of the fuel cell stack.

3. The low leakage loss energy storage unit according to claim 1, characterized in that, The lengths of the fuel cell stack liquid inlet branch main line and the fuel cell stack liquid outlet branch main line are 6.5m.

4. The low leakage loss energy storage unit according to claim 1, characterized in that, The fuel cell stack inlet branch main pipeline and the fuel cell stack outlet branch main pipeline adopt a straight pipe section planar laying method.

5. The low leakage loss energy storage unit according to claim 1, characterized in that, The battery stack is a 750KW battery module.

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