A method for designing and evaluating performance of a battery bipolar plate biomimetic flow guide structure

Abstract

The application relates to the technical field of seawater activated batteries. A kind of battery bipolar plate biomimetic flow guide structure design includes upper bottom plate;Lower bottom plate, which is provided with three first-stage inlet flow channel openings and a plurality of second-stage inlet flow channel openings, one end of the three first-stage inlet flow channel openings is communicated with a seawater inlet, and the other end of each first-stage inlet flow channel opening is communicated with at least one second-stage inlet flow channel opening;In addition, the lower bottom plate is provided with three first-stage outlet flow channel openings and a plurality of second-stage outlet flow channel openings, one end of the three first-stage outlet flow channel openings is communicated with a seawater outlet, and the other end of each first-stage outlet flow channel opening is communicated with at least one second-stage outlet flow channel opening;Reaction zone, arranged downstream of the plurality of second-stage inlet flow channel openings, so that seawater flowing out through the plurality of second-stage inlet flow channel openings enters the reaction zone, and arranged upstream of the plurality of second-stage outlet flow channel openings, so that seawater after reaction in the reaction zone enters the second-stage outlet flow channel openings. The above structure has more branch flow channels and flow channel openings, can increase branch pipe resistance, and reduce the flow dead zone area of the reaction zone.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of seawater activated battery, and particularly to a battery bipolar plate biomimetic flow guide structure design and performance evaluation method. BACKGROUND

[0002] The existing seawater activated battery bipolar plate flow guide structure is a four-flow channel straight-through type flow channel structure. Although this structure has certain advantages in manufacturing, the advantages can be ignored compared to its poor water conductivity, small branch pipe resistance and large weight. In addition, the limited flow channel port makes the fluid flow into the bipolar plate from the lower inlet, and then enter the reaction zone through the branch channel, which has a large flow cross-section mutation, and vortexes are easily generated on both sides of each branch channel, which greatly reduces the fluid flow activity in the reaction zone, produces fluid flow dead zones that are not conducive to battery discharge, reduces the utilization rate of the electrode plate, and ultimately leads to poor battery discharge performance. SUMMARY

[0003] The battery bipolar plate biomimetic flow guide structure design and performance evaluation method provided by the present application can solve the problem of unreasonable design of the existing seawater activated battery bipolar plate, which leads to poor utilization rate of the positive and negative electrode plates and inhibits the energy efficiency of the battery body.

[0004] The present application provides a battery bipolar plate biomimetic flow guide structure design, which comprises:

[0005] an upper bottom plate;

[0006] a lower bottom plate, which is provided with three primary inlet flow channel ports and a plurality of secondary inlet flow channel ports, one end of each of the three primary inlet flow channel ports being in communication with a seawater inlet, and the other end of each of the primary inlet flow channel ports being in communication with at least one of the secondary inlet flow channel ports; in addition, the lower bottom plate is provided with three primary outlet flow channel ports and a plurality of secondary outlet flow channel ports, one end of each of the three primary outlet flow channel ports being in communication with a seawater outlet, and the other end of each of the primary outlet flow channel ports being in communication with at least one of the secondary outlet flow channel ports;

[0007] a reaction zone, which is arranged downstream of the plurality of secondary inlet flow channel ports so that seawater flowing out of the plurality of secondary inlet flow channel ports enters the reaction zone, and is arranged upstream of the plurality of secondary outlet flow channel ports so that seawater reacted in the reaction zone enters the secondary outlet flow channel ports; wherein,

[0008] The seawater inlet and the seawater outlet are oppositely arranged at two ends of the lower bottom plate, and with the center line of the seawater inlet and the seawater outlet as an axis, three first inlet flow channel openings, a plurality of second inlet flow channel openings, three first outlet flow channel openings and a plurality of second outlet flow channel openings are symmetrically arranged; the upper bottom plate and the lower bottom plate enclose a space for accommodating the three first inlet flow channel openings, the plurality of second inlet flow channel openings, the three first outlet flow channel openings and the plurality of second outlet flow channel openings.

[0009] In some modes of implementation, the three first inlet flow channel openings include a first first inlet flow channel opening, a second first inlet flow channel opening and a third first inlet flow channel opening, the first first inlet flow channel opening and the second first inlet flow channel opening are symmetrically arranged on the two sides of the seawater inlet; and the third first inlet flow channel opening is arranged on the axis.

[0010] In some modes of implementation, the included angle between the first first inlet flow channel opening and the third first inlet flow channel opening is one of 90°, 95°, 100°, 105° or 110°.

[0011] In some modes of implementation, the plurality of second inlet flow channel openings form a first comb structure, and the first first inlet flow channel opening and the second first inlet flow channel opening are away from the direction of the seawater inlet, and the tooth length of the first comb gradually decreases.

[0012] In some modes of implementation, the three first outlet flow channel openings include a first first outlet flow channel opening, a second first outlet flow channel opening and a third first outlet flow channel opening, the first first outlet flow channel opening and the second first outlet flow channel opening are symmetrically arranged on the two sides of the seawater inlet; and the third first outlet flow channel opening is arranged on the axis.

[0013] In some modes of implementation, the included angle between the first first outlet flow channel opening and the third first outlet flow channel opening is one of 90°, 95°, 100°, 105° or 110°.

[0014] In some modes of implementation, the plurality of second outlet flow channel openings form a second comb structure, and the first first outlet flow channel opening and the second first outlet flow channel opening are away from the direction of the seawater outlet, and the tooth length of the second comb gradually decreases.

[0015] In some modes of implementation, the reaction zone includes a plurality of array-arranged turbulence columns, one end of the turbulence column is connected with the upper bottom plate, and the other end is connected with the lower bottom plate.

[0016] In some modes of implementation, the outer edge curve parameters of the first inlet flow channel opening and the first outlet flow channel opening are y respectively, where,

[0017] The expression of y is:

[0018]

[0019] Wherein, y is the outer edge curve parameter of the import and export flow guide groove, H is the first length, h is the second length, D is the third length, x m is the first proportional coefficient, y0 is the first fitting coefficient, A1 and A2 are the second fitting coefficient and the third fitting coefficient, t1 and t2 are the fourth fitting coefficient and the fifth fitting coefficient.

[0020] The application also comprises a battery bipolar plate biomimetic flow guide structure design performance evaluation method, which is applied to the battery bipolar plate biomimetic flow guide structure design, and the method comprises the following steps:

[0021] S100, a three-dimensional drawing software is used to model the seawater activated battery bipolar plate biomimetic flow guide structure multiple times, and a quality attribute module carried by the three-dimensional drawing software itself is used to calculate initial simulation values of multiple models corresponding to the modeling;

[0022] S200, a difference value calculation is performed on one of the initial simulation values and an existing flow channel structure to obtain lightweight degree gap data;

[0023] S300, a real object formed by one of the modeling is weighed, and the existing flow channel structure is weighed, and a comparison is performed between the weighing result gap of the two and the lightweight degree gap data to obtain a gap value;

[0024] If the gap value is less than a preset value, the verification result is accurate:

[0025] According to the initial simulation values of the multiple models, target simulation values of the multiple models are obtained;

[0026] S400, an electrical resistance formula is used to perform electrical resistance calculation on the target simulation values of the multiple models to obtain electrical resistance maps of the multiple models;

[0027] S500, an image processing method is used to identify the area of the gas phase region and the total area of the electrode plate flow channel, and the gas phase proportion is calculated;

[0028] S600, the time required for filling the fluid into three primary inlet flow channel openings and a plurality of secondary inlet flow channel openings, the time required for filling the reaction area, and the time required for filling the fluid into three primary outlet flow channel openings and a plurality of secondary outlet flow channel openings are recorded.

[0029] The application has the following beneficial effects:

[0030] The application discloses a battery bipolar plate bionic flow guide structure design, three first-level flow inlet ports and a plurality of second-level flow inlet ports are arranged on a lower bottom plate, one end of the three first-level flow inlet ports is communicated with a seawater inlet, and the other end of each first-level flow inlet port is communicated with at least one second-level flow inlet port; in addition, three first-level flow outlet ports and a plurality of second-level flow outlet ports are arranged on the lower bottom plate, one end of the three first-level flow outlet ports is communicated with a seawater outlet, and the other end of each first-level flow outlet port is communicated with at least one second-level flow outlet port; a reaction area is arranged downstream of the plurality of second-level flow inlet ports, so that seawater flowing out of the plurality of second-level flow inlet ports enters the reaction area, and the reaction area is arranged upstream of the plurality of second-level flow outlet ports, so that seawater after reaction in the reaction area enters the plurality of second-level flow outlet ports. Further, the seawater inlet and the seawater outlet are oppositely arranged at two ends of the lower bottom plate, and the three first-level flow inlet ports, the plurality of second-level flow inlet ports, the three first-level flow outlet ports and the plurality of second-level flow outlet ports are symmetrically arranged with the center line of the seawater inlet and the seawater outlet as an axis; the upper bottom plate and the lower bottom plate jointly enclose a space for accommodating the three first-level flow inlet ports, the plurality of second-level flow inlet ports, the three first-level flow outlet ports and the plurality of second-level flow outlet ports. The above structure has more branch flow channels and more flow port, and can effectively increase branch pipe resistance and reduce the flow dead area of the reaction area. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0032] Figure 1 It is a structural schematic diagram of the bionic flow guide structure design of the battery bipolar plate of the present application.

[0033] Figure 2 It is a fluid domain plan view of the flow guide structure of the bionic flow guide structure design of the battery bipolar plate of the present application.

[0034] Figure 3 It is an outer edge curve diagram of the flow guide structure of the bionic flow guide structure design of the battery bipolar plate of the present application.

[0035] Figure 4 It is a partial enlarged view of Figure 1

[0036] Figure 5 It is a main stem distribution diagram and a structural variable schematic diagram of the tree root type flow guide structure of the bionic flow guide structure design of the battery bipolar plate of the present application, wherein the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides is 110°.

[0037] ​Figure 6 It is the main stem distribution diagram and structure variable schematic view of the tree root type flow guide structure of the battery bipolar plate biomimetic flow guide structure design of the application, wherein the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides is 105°.

[0038] Figure 7 It is the main stem distribution diagram and structure variable schematic view of the tree root type flow guide structure of the battery bipolar plate biomimetic flow guide structure design of the application, wherein the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides is 100°.

[0039] Figure 8 It is the main stem distribution diagram and structure variable schematic view of the tree root type flow guide structure of the battery bipolar plate biomimetic flow guide structure design of the application, wherein the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides is 95°.

[0040] Figure 9 It is the main stem distribution diagram and structure variable schematic view of the tree root type flow guide structure of the battery bipolar plate biomimetic flow guide structure design of the application, wherein the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides is 90°.

[0041] Figure 10 It is the comparison diagram of the embodiments 1 to 5 of the battery bipolar plate biomimetic flow guide structure design of the application.

[0042] Explanation of reference signs:

[0043] 1, upper bottom plate; 2, lower bottom plate; 3, seawater inlet; 4, seawater outlet; 5, secondary flow channel port; 6, primary flow channel port; 7, turbulence column. DETAILED DESCRIPTION

[0044] The technical solutions of the application will be described below in conjunction with the embodiments, obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0045] In the description of the application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0046] Furthermore, the terms "first", "second", "third", etc. are used herein for descriptive purposes only and should not be construed as indicating or implying relative importance or an ordered sequence. Thus, features defined with "first", "second" or "third" can include one or more of the features. In the description of the application, the meaning of "a plurality" is two or more, unless expressly specified otherwise. Furthermore, the terms "mounting", "connected", "connecting" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0047] With the development of current society, the consumption of primary energy is huge, and it is urgent to develop new energy to replace the original primary energy. As a new advanced energy supply technology, seawater activated battery can make a significant contribution to the existing energy shortage problem, and can provide high energy density, high specific property and power supply without external electrolyte for electrical equipment. In addition, the application of seawater activated battery in underwater field is the research trend of current scholars. Lightweight is an important trend of seawater activated battery for underwater application, and the discharge performance of seawater activated battery depends largely on the design of flow field. However, during the flow of electrolyte between the bipolar plates of the battery, bubbles and some flow dead zones may occur, which seriously affects the utilization rate of the plates. Reducing the volume of bubbles between the plates and the area of flow dead zones and improving the utilization rate of the plates are one of the effective ways to improve the discharge capacity of seawater activated battery. In addition, in actual application, the seawater activated battery is mostly in the form of multiple single batteries connected in series to form a module, and this common electrolyte mode is prone to cause leakage and large power supply configuration weight ratio problems. Therefore, increasing the branch pipe resistance and reducing the power supply configuration weight ratio are also key technical problems to be solved at present.

[0048] The purpose of the present application is to provide a kind of battery bipolar plate bionic flow guide structure design. The battery bipolar plate bionic flow guide structure design of the present application is based on the root structure characteristics of a certain tree and combines its root fractal concept to design a new root type bipolar plate flow guide structure, which has more branch channels and more flow channel openings, can effectively increase the branch pipe resistance and reduce the flow dead zone area of reaction zone.

[0049] As shown in Figure 1 The present application provides a kind of battery bipolar plate bionic flow guide structure design, including upper bottom plate 1, lower bottom plate 2 and reaction zone.

[0050] The lower bottom plate 2 is provided with three first inlet flow channels and a plurality of second inlet flow channels. One end of each of the three first inlet flow channels is in communication with the seawater inlet 3, and the other end of each of the first inlet flow channels is in communication with at least one second inlet flow channel. In addition, the lower bottom plate 2 is provided with three first outlet flow channels and a plurality of second outlet flow channels. One end of each of the three first outlet flow channels is in communication with the seawater outlet 4, and the other end of each of the first outlet flow channels is in communication with at least one second outlet flow channel.

[0051] It should be noted that the three first inlet flow channels include a first first inlet flow channel, a second first inlet flow channel, and a third first inlet flow channel. The first first inlet flow channel and the second first inlet flow channel are symmetrically arranged on both sides of the seawater inlet 3. The third first inlet flow channel is arranged on the axis. The included angle between the first first inlet flow channel and the third first inlet flow channel is one of 90°, 95°, 100°, 105°, or 110°. The plurality of second inlet flow channels form a first comb structure, and the tooth length of the first comb gradually decreases away from the seawater inlet 3.

[0052] It should also be noted that the first inlet flow channel and the second inlet flow channel on the lower bottom plate 2 correspond to the first outlet flow channel and the second outlet flow channel. The first outlet flow channel and the second outlet flow channel can be mirror image arranged. Specifically, the three first outlet flow channels include a first first outlet flow channel, a second first outlet flow channel, and a third first outlet flow channel. The first first outlet flow channel and the second first outlet flow channel are symmetrically arranged on both sides of the seawater inlet 3. The third first outlet flow channel is arranged on the axis. The included angle between the first first outlet flow channel and the third first outlet flow channel is one of 90°, 95°, 100°, 105°, or 110°. The plurality of second outlet flow channels form a second comb structure, and the tooth length of the second comb gradually decreases away from the seawater outlet 4.

[0053] The reaction zone is arranged downstream of the plurality of second inlet flow channels, so that the seawater flowing out of the plurality of second inlet flow channels enters the reaction zone. In addition, the reaction zone is arranged upstream of the plurality of second outlet flow channels, so that the seawater reacted in the reaction zone enters the plurality of second outlet flow channels.

[0054] The reaction zone includes a plurality of array-arranged turbulence columns 7. One end of each of the turbulence columns 7 is connected to the upper bottom plate 1, and the other end is connected to the lower bottom plate 2. Exemplarily, the reaction zone has a rectangular structure.

[0055] Specifically, the seawater inlet 3 and the seawater outlet 4 are oppositely arranged at two ends of the lower bottom plate 2, and with the center line of the seawater inlet 3 and the seawater outlet 4 as an axis, three primary inlet flow channel openings, a plurality of secondary inlet flow channel openings, three primary outlet flow channel openings and a plurality of secondary outlet flow channel openings are symmetrically arranged; the upper bottom plate 1 and the lower bottom plate 2 jointly form a space for accommodating the three primary inlet flow channel openings, the plurality of secondary inlet flow channel openings, the three primary outlet flow channel openings and the plurality of secondary outlet flow channel openings.

[0056] The embodiment of the application is a kind of battery bipolar plate bionic flow guide structure design, including upper bottom plate 1 and the lower bottom plate 2 engraved with flow channel constitute, overall presents axial symmetry distribution, the outline of upper bottom plate 1 and lower bottom plate 2 is flat cylindrical structure.Fluid is communicated by three primary inlet flow channel openings of lower seawater inlet 3 into the flow channel of bipolar plate, flows to three primary outlet flow channel openings through intermediate square reaction area, next, again, flows out by seawater outlet 4.The fluid domain includes a plurality of secondary flow channel openings 5 (secondary inlet flow channel opening and secondary outlet flow channel opening), three primary flow channel openings 6 (primary inlet flow channel opening and primary outlet flow channel opening) and a plurality of turbulence columns 7.According to the flow direction of fluid into bipolar plate, the flow channel deflection angle is defined as the included angle between vertical direction and left and right sides, the application is 90 °, 95 °, 100 °, 105 °, 110 ° respectively, the rest of the flow channel branch is divided into the trunk structure of certain tree.This is because trees rely on roots to absorb water from the soil to survive, and this natural distribution feature creates excellent water conductivity, which is one of the optimization factors of seawater activated battery bipolar plate flow channel structure design.Therefore, the application is based on the roots of certain trees, and a battery bipolar plate bionic flow guide structure design is provided.In addition.

[0057] Embodiment 1

[0058] As Figures 1 to 4 shown, Figure 1 is a schematic diagram of a tree root type flow guide structure, the overall structure presents axial symmetry distribution, which is composed of upper bottom plate 1 and lower bottom plate 2 with flow channel, the outline of upper bottom plate 1 and lower bottom plate 2 is flat cylindrical structure, the height is 0.083D (D represents the abbreviation of diameter, the same below, no need to be repeated), and the diameter is 14.167D. Figure 2 is a top view of fluid domain in flow guide structure, the outer edge curve parameter of flow guide groove is y; wherein, Figure 3 , the expression of y is:

[0059]

[0060] In the formula, y is the outer edge curve parameter of the inlet and outlet flow guide groove, H is the first length, h is the second length, D is the third length, x mis a first proportional coefficient, y0 is a first fitting coefficient, A1 and A2 are a second fitting coefficient and a third fitting coefficient, t1 and t2 are a fourth fitting coefficient and a fifth fitting coefficient, and the midpoint of the upper edge line of the reaction zone is taken as the origin.

[0061] Fluids enter the bipolar plate flow channel from the lower inlet 4, flow through the middle square reaction zone (length* width = 8.333D*8.333D) to the upper outlet 3, and then flow out. Figure 4 It is a local enlarged view of the flow guide structure fluid domain, including a plurality of secondary flow channel openings 5 (flow channel opening cross-sectional area 1.4014~1.87155mm 2 It should be noted that the more secondary flow channel openings 5 are arranged near the reaction zone side, the smaller the fluid impulse when flowing through the secondary flow channel into the reaction zone, thereby reducing the probability of vortex flow on both sides of the secondary flow channel. The area occupied by the vortex flow will reduce the utilization rate of the electrode plate at this place. However, due to the most unfavorable value of the width of each secondary flow channel, the number of secondary flow channels cannot be increased indefinitely. Since the seawater activated battery is composed of several hundred battery monomers in actual use, it will produce a leakage phenomenon. The most unfavorable value of the width here refers to the critical value that affects the size of the branch resistance. The wider the width, the smaller the branch resistance, and the larger the leakage current. Three primary flow channel openings 6 (flow channel opening cross-sectional area 4.1425~9.4248mm 2 It should be noted that the flow angle of the fluid entering the secondary flow channel from the main circular flow channel is a right angle. When designing the flow channel at this place, the momentum loss of the fluid flowing through the right-angle flow channel needs to be minimized, which requires minimizing the number of primary flow channel openings 6. Therefore, the present application proposes three primary flow channel openings 6, which correspond to the middle and left and right sides, respectively. And a plurality of turbulence columns 7 (diameter 0.167D, height 0.0417D).

[0062] Figure 5This diagram illustrates the main distribution and structural variables of a root-type flow guide structure. Based on the flow direction of the fluid entering the bipolar plate, the flow channel deflection angle is defined as the angle between the vertical direction and the left and right sides; in this case, it is 110°. The remaining flow channel branches are divided according to the trunk-like structure of a tree. Taking the right-side trunk-like structure as an example, the gas-liquid phase ratio is used as the evaluation criterion. Through tracer experiments and numerical simulations, the reasonable range of the deflection angle design for each flow channel branch is monitored. When the deflection angle of the first secondary branch should be greater than or equal to 122°, and the deflection angles of the remaining channels are maintained between 97° and 114°, the gas phase ratio in each secondary flow channel can be minimized. A higher gas phase ratio will lead to an increase in the area of ​​the gas phase flowing into the reaction zone, thereby reducing the utilization rate of the electrode plates. Compared with the traditional four-channel straight-through structure, this structural design increases the length of the branch channels and improves the branch resistance. Meanwhile, compared with the traditional four flow channels, the multi-flow channel design proposed in this invention reduces the impulse of fluid flowing through the secondary flow channels into the reaction zone, slows down the turbulent kinetic energy on both sides, reduces the flow dead zone area, and improves the utilization rate of the electrode plates, thereby effectively improving the battery discharge performance.

[0063] Example 2

[0064] The upper base plate 1 and lower base plate 2 are the same as in Embodiment 1, and will not be described again. The calculation method for the outer edge curve parameters of the guide channel is the same as in Embodiment 1, with several secondary flow channel openings 5 ​​(flow channel opening cross-sectional area 1.2568~2.05005mm²). 2 Three primary flow channels 6 (flow channel cross-sectional area of ​​4.1425~12.9663mm²) 2 ) and several turbulence columns 7 (0.167D in diameter and 0.0417D in height). Figure 6 This diagram shows the main distribution of the root-type flow guide structure and a schematic diagram of its structural variables. Based on the flow direction of the fluid entering the bipolar plate, the flow channel deflection angle is defined as the angle between the vertical direction and the left and right sides, which is 105° in this case. The remaining flow channel branches are divided according to the trunk-type structure of a certain tree.

[0065] Example 3

[0066] The upper base plate 1 and the lower base plate 2 are the same as in Embodiment 1, and will not be described again. The fluid enters the bipolar plate flow channel through the lower inlet 4, flows through the middle square reaction zone (length * width = 8.333D * 8.333D) to the upper outlet 3 and then flows out. Figure 4 This is a magnified view of a portion of the fluid domain of the flow guiding structure, including several secondary flow channels 5 (flow channel cross-sectional area 1.155–2.1478 mm²). 2 ), three primary flow channel openings 6 (flow channel opening cross-sectional area of ​​4.1425~13.12045mm), 2 ) and several turbulence columns 7 (0.167D in diameter and 0.0417D in height).Figure 7 Figure 4 is a schematic diagram of the main stem distribution and structure variables of the tree root type flow guide structure. According to the flow direction of the fluid into the bipolar plate, the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides. In this case, the angle is 100°. The remaining flow channel branches are divided in the stem type structure of a tree.

[0067] Example 4

[0068] The upper bottom plate 1 and the lower bottom plate 2 are the same as in Example 1 and will not be described again. The fluid enters the bipolar plate flow channel from the lower side inlet 4, flows through the middle square reaction area (length * width = 8.333D * 8.333D) to the upper side outlet 3, and then flows out. Figure 4 Figure 5 is a partial enlarged view of the fluid domain of the flow guide structure, including several secondary flow channel openings 5 (flow channel opening cross-sectional area 1.0304-2.1423 mm2), three primary flow channel openings 6 (flow channel opening cross-sectional area 4.1425-13.0208 mm2), and several turbulence columns 7 (diameter 0.167D, height 0.0417D). 2 2 Figure 8 Figure 6 is a schematic diagram of the main stem distribution and structure variables of the tree root type flow guide structure. According to the flow direction of the fluid into the bipolar plate, the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides. In this case, the angle is 95°. The remaining flow channel branches are divided in the stem type structure of a tree.

[0069] Example 5

[0070] The upper bottom plate 1 and the lower bottom plate 2 are the same as in the previous examples and will not be described again. Figure 2 Figure 7 is a top view of the fluid domain in the flow guide structure. The fluid enters the bipolar plate flow channel from the lower side inlet 4, flows through the middle square reaction area (length * width = 8.333D * 8.333D) to the upper side outlet 3, and then flows out. Figure 4 Figure 8 is a partial enlarged view of the fluid domain of the flow guide structure, including several secondary flow channel openings 5 (flow channel opening cross-sectional area 0.92275-2.07185 mm2), three primary flow channel openings 6 (flow channel opening cross-sectional area 4.1425-12.83575 mm2), and several turbulence columns 7 (diameter 0.167D, height 0.0417D). As shown in Figure 8, according to the flow direction of the fluid into the bipolar plate, the flow channel deflection angle is defined as the included angle between the vertical direction and the left and right sides. In this case, the angle is 90°. The remaining flow channel branches are divided in the stem type structure of a certain tree. Figure 9

[0071] ​​​Compared with the traditional four-flow straight-through structure, the above structural design not only increases the length of the branch flow channel and improves the branch resistance, but also, compared with the traditional four-flow channel, the multi-flow channel design reduces the impulse of the fluid flowing through the secondary flow channel into the reaction zone, slows down the turbulent kinetic energy on both sides, reduces the flow dead zone area, improves the utilization rate of the electrode plate, and thus can effectively improve the battery discharge performance.

[0072] According to the battery bipolar plate biomimetic flow guide structure design disclosed in embodiments 1-5, there is a battery bipolar plate biomimetic flow guide structure performance evaluation method, also known as a quantitative evaluation method, which can be used to test the lightweight of the tree trunk type flow guide structure. The specific steps are as follows:

[0073] S100, using three-dimensional drawing software to model the seawater activated battery bipolar plate biomimetic flow guide structure multiple times, and using the quality attribute module carried by the three-dimensional drawing software itself to calculate the initial simulation value of the multiple modeling corresponding models;

[0074] S200, difference calculation of an initial simulation value and an existing flow channel structure to obtain lightweight degree gap data;

[0075] S300, weighing the physical object formed by one modeling, and weighing the existing flow channel structure, and calculating the difference between the two weighing results and the lightweight degree gap data to obtain the gap value;

[0076] If the gap value is less than the preset value, the verification result is accurate:

[0077] According to the initial simulation value of the multiple models, the target simulation value of the multiple models is obtained;

[0078] S400, using the resistance formula to calculate the resistance of the target simulation value of the multiple models to obtain the resistance map of the multiple models;

[0079] S500, using image processing method to identify the area of gas phase region and total area of electrode plate flow channel, and calculate the gas phase proportion;

[0080] S600, record the time required to fill the three primary inlet flow channel openings and the several secondary inlet flow channel openings, the time required to fill the reaction zone, and the time required to fill the three primary outlet flow channel openings and the several secondary outlet flow channel openings.

[0081] Specifically, the first step: through the use of three-dimensional design software, for example, SOLIDWORKS, model the designed tree trunk type flow guide structure (embodiments 1-5).

[0082] On the one hand, the lightweight degree gap between the model proposed in the application and the traditional flow channel structure is calculated by the quality attribute module of the software; on the other hand, the lightweight degree of the model of example 1 proposed in the application is measured by an electronic balance, and the result is compared with the simulation value, and after verifying the accuracy of the result, the remaining four flow guide structures do not need to be verified and can be directly referred to the simulation value.

[0083] The lightweight degree refers to the ratio of the mass of the optimized and manufactured bipolar plate flow channel structure to the mass of the traditional flow channel structure, and the specific calculation formula is as follows:

[0084]

[0085] In the formula, ε is the lightweight degree, and the smaller the value is, the better; M o is the mass of the optimized bipolar plate; and M t is the mass of the traditional bipolar plate.

[0086] Second step: the branch pipe resistance of examples 1 to 5 proposed is calculated by using the branch pipe resistance formula 1, and is plotted into a graph for comparison, as shown in FIG. 2. Figure 10 As can be seen from the resistance graph, with the increase of the flow channel deflection angle, the branch pipe resistance of examples 1 to 5 increases nearly linearly. It should be noted that when the flow channel deflection angle is greater than 90° and less than 100°, with the increase of the flow channel deflection angle, the branch pipe resistance increases linearly; when the flow channel deflection angle is greater than 100° and less than 110°, the growth trend is obviously weakened.

[0087] The branch pipe resistance refers to the resistance of each branch pipe at the inlet and outlet of the electro-hydraulic tank, and the greater the branch pipe resistance is, the smaller the leakage current is, and the less the current loss is. The branch pipe resistance calculation formula is as follows:

[0088]

[0089] In the formula, ρ is the material density, kg / m 3 ; L is the material length, m; and S is the material cross-sectional area, m 2 .

[0090] Third step: the area of the gas phase region and the total area of the electrode plate flow channel are identified by using an image processing software, such as ImageJ software, and the gas phase ratio is calculated.

[0091] The gas-liquid ratio refers to the proportion of the gas (liquid) on the electrode plate total area on the electrode plate flow channel cross section:

[0092]

[0093]

[0094] In the formula, A GA is the area of the gas phase region in the electrode plate, m 2 ; A t A is the total area of the flow channel of the electrode plate, m 2 ; A LR A is the area of the liquid phase region in the electrolyte tank, m 2 ; A GR The calculation of A uses the image processing method of ImageJ software to identify the area of the gas phase region and the total area of the flow channel of the electrode plate. When no liquid flows into the electrode plate, A is 1. When the electrode plate is filled with fluid, A is 0. GR GR

[0095] Step 4: Observe and record the time required to fill the inlet side flow channel, the time required to fill the reaction area, and the time required to fill the outlet side flow channel.

[0096] The change of the liquid level height of the fluid in the electrode plate after entering from the inlet is divided into three time periods: the filling time t1 of the inlet side flow channel of the test piece, the filling time t2 of the reaction area flow channel of the test piece, and the filling time t3 of the outlet flow channel of the test piece. The time required to fill the bipolar plate is t.

[0097] t = t1 + t2 + t3 (5)

[0098] In summary, the quantity relationship between the two found by the present application can provide technical support for subsequent optimization design of the flow channel structure of the seawater activated battery bipolar plate.

[0099] The branch pipe resistance refers to the resistance of each branch pipe at the inlet and outlet of the electrolyte tank. The larger the branch pipe resistance, the smaller the leakage current, and the less the current loss. The branch pipe resistance calculation formula is as follows:

[0100]

[0101] In the formula, ρ is the material density, kg / m 3 ; L is the material length, m; and S is the material cross-sectional area, m 2 .

[0102] The battery bipolar plate bionic flow guide structure design performance evaluation method provided in the embodiment compares the data in embodiments 1 to 5 corresponding to multiple modeling with the existing flow channel structure, and it can be concluded from multiple aspects that the present application is superior to the existing flow channel structure. The present application aims to solve the problems of large weight and violation of the lightweight concept of seawater activated batteries applied in underwater fields, and the problem of large dead zone area of the reaction area of the bipolar plate in the prior art.

[0103] In summary, the battery bipolar plate bionic flow guide structure design performance evaluation method provided by the present application has the following advantages:

[0104] ​​1. High water conductivity. The seawater activated battery bipolar plate biomimetic flow guide structure designed by the inventor inspired by the tree roots also has high water conductivity of the tree roots.

[0105] 2. Easy to process and low cost. The bipolar plate flow channel structure proposed by the inventor can easily draw the flow channel contour according to the main trunk line, and complete the batch production after the mold manufacturing.

[0106] 3. Large branch pipe resistance. The bipolar plate flow channel structure proposed by the inventor is longer and has larger resistance than the branch flow channel of the traditional four-flow channel straight-through structure.

[0107] 4. High degree of lightweight. Because more flow channels are engraved on the bipolar plate, the weight of the plate material is significantly reduced. Therefore, the weight is lighter.

[0108] 5. Small reaction zone flow dead zone area. The multiple secondary flow channel openings 5 proposed by the inventor can effectively slow down the turbulent flow energy when the fluid changes from a narrow to a wide channel, inhibit the formation of vortex on both sides of the flow channel, and further reduce the area of the flow dead zone.

[0109] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for evaluating the performance of a battery bipolar plate biomimetic flow guiding structure design, characterized in that, The battery bipolar plate biomimetic flow guide structure design comprises: an upper bottom plate; a lower bottom plate, which is provided with three first-level inlet flow channel openings and a plurality of second-level inlet flow channel openings, one end of each of the three first-level inlet flow channel openings being communicated with a seawater inlet, and the other end of each of the first-level inlet flow channel openings being communicated with at least one of the second-level inlet flow channel openings; in addition, the lower bottom plate is provided with three first-level outlet flow channel openings and a plurality of second-level outlet flow channel openings, one end of each of the three first-level outlet flow channel openings being communicated with a seawater outlet, and the other end of each of the first-level outlet flow channel openings being communicated with at least one of the second-level outlet flow channel openings; a reaction zone, which is arranged downstream of the plurality of second-level inlet flow channel openings so that seawater flowing out of the plurality of second-level inlet flow channel openings enters the reaction zone, and is arranged upstream of the plurality of second-level outlet flow channel openings so that seawater reacted in the reaction zone enters the plurality of second-level outlet flow channel openings; wherein the seawater inlet and the seawater outlet are arranged at opposite ends of the lower bottom plate, and the three first-level inlet flow channel openings, the plurality of second-level inlet flow channel openings, the three first-level outlet flow channel openings and the plurality of second-level outlet flow channel openings are symmetrically arranged with the center line of the seawater inlet and the seawater outlet as the axis; the upper bottom plate and the lower bottom plate jointly form a space for accommodating the three first-level inlet flow channel openings, the plurality of second-level inlet flow channel openings, the three first-level outlet flow channel openings and the plurality of second-level outlet flow channel openings; the method comprises: S100, using a three-dimensional drawing software to model the seawater activated battery bipolar plate biomimetic flow guide structure multiple times, and using the quality attribute module carried by the three-dimensional drawing software to calculate initial simulation values of the models corresponding to the modeling; S200, performing difference calculation on one of the initial simulation values and an existing flow channel structure to obtain lightweight degree gap data; S300, weighing the physical object formed by one of the modeling and the existing flow channel structure, and calculating the difference between the weighing results of the two and the lightweight degree gap data to obtain a gap value; if the gap value is less than a preset value, the verification result is accurate: according to the initial simulation values of the models, target simulation values of the models are obtained; S400, using a resistance formula to calculate the resistance of the target simulation values of the models to obtain a resistance map of the models; S500, using an image processing method to identify the area of the gas phase region and the total area of the electrode plate flow channel, and calculating the gas phase proportion; S600, recording the time required to fill the three first-level inlet flow channel openings and the plurality of second-level inlet flow channel openings, the time required to fill the reaction zone, and the time required to fill the three first-level outlet flow channel openings and the plurality of second-level outlet flow channel openings.

2. The method of claim 1, wherein the method is characterized by: The three first-level inlet flow channel openings comprise a first first-level inlet flow channel opening, a second first-level inlet flow channel opening and a third first-level inlet flow channel opening, the first first-level inlet flow channel opening and the second first-level inlet flow channel opening being symmetrically arranged on the two sides of the seawater inlet; and the third first-level inlet flow channel opening being arranged on the axis.

3. The method of claim 2, wherein the method is characterized by: The included angle between the first first-level inlet flow channel opening and the third first-level inlet flow channel opening is one of 90°, 95°, 100°, 105° or 110°.

4. The method of claim 3, wherein the method is characterized by: A plurality of the secondary inlet flow channel openings form a first comb structure, and the first primary inlet flow channel opening and the second primary inlet flow channel opening are away from the direction of the seawater inlet, and the teeth of the first comb gradually become shorter.

5. The method of claim 1, wherein the method is characterized by: The three primary outlet flow channel openings include a first primary outlet flow channel opening, a second primary outlet flow channel opening, and a third primary outlet flow channel opening, the first primary outlet flow channel opening and the second primary outlet flow channel opening are symmetrically arranged on both sides of the seawater inlet; and the third primary outlet flow channel opening is arranged on the axis.

6. The method of claim 5, wherein the method is characterized by: The included angle between the first primary outlet flow channel opening and the third primary outlet flow channel opening is one of 90°, 95°, 100°, 105°, or 110°.

7. The method of claim 6, wherein the method further comprises: A plurality of the secondary outlet flow channel openings form a second comb structure, and the first primary outlet flow channel opening and the second primary outlet flow channel opening are away from the direction of the seawater outlet, and the teeth of the second comb gradually become shorter.

8. The method of claim 1, wherein the method is characterized by: The reaction zone includes a plurality of arrayed turbulence columns, one end of the turbulence column is connected with the upper bottom plate, and the other end is connected with the lower bottom plate.

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