3D diversion temperature management system of air-cooled energy storage battery cabinet

Abstract

The invention relates to a 3D diversion temperature management system of an air-cooled energy storage battery cabinet, and belongs to the technical field of heat management systems of air-cooled energy storage battery cabinets. The temperature management system comprises a cabinet body and an air conditioner, multiple layers of battery packs are arranged in the cabinet body, a fan is arranged at the front end of each battery pack, a 3D flow guide cover is arranged at the top of the cabinet body, a composite flow channel communicated with an air outlet of the air conditioner is formed in the 3D flow guide cover, and the composite flow channel comprises an upper flow channel and a lower flow channel. And the lower runner consists of a main runner and a plurality of auxiliary runners. Cold air flow entering the battery cabinet is guided and shunted through the composite flow channel in the 3D flow guide cover, one part of the cold air flow enters the battery pack from an opening in the rear end of the battery pack, the other part of the cold air flow enters the front portion of the battery pack from an opening in the side face of the battery pack, then the air flow in the battery pack is pumped out through the fan, the overall temperature uniformity of the battery cabinet is improved, and the service life of the battery cabinet is prolonged. And the service life of the battery can be prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal management systems for air-cooled energy storage battery cabinets, and in particular relates to a 3D flow diversion temperature management system for an air-cooled energy storage battery cabinet. Background Art

[0002] With the continuous development of energy storage technology, air cooling temperature management has become a widely used heat dissipation method in various energy storage devices. Especially in the field of battery packs, since battery performance is closely related to temperature, ensuring that the battery works within the appropriate temperature range is the key to improving the performance of energy storage batteries and extending battery life. The heat dissipation problem inside the battery pack, especially the uneven distribution of temperature uniformity and fluid flow rate, has become one of the main factors affecting the efficiency and safety of energy storage systems.

[0003] At present, most air-cooled energy storage systems on the market use the rear air intake method for cooling. This method allows cold air to enter from the rear side of the top of the battery cabinet, then enter the front side of the battery pack through the vents, and flow from the front side to the inside of each layer of the battery pack to achieve heat dissipation of the battery cells. Although this method can meet the heat dissipation requirements of the battery pack to a certain extent, the non-uniformity of the cold air flow path and cold air flow rate needs to be improved, and there are the following adverse effects:

[0004] (1) Thermal cascade phenomenon: Since cold air enters from the front of the battery pack and flows to each layer of the battery pack in turn, the flow of cold air in the battery pack is directional. As the air flows, the cold air gradually heats up, forming a thermal cascade effect from front to back. This will cause uneven temperature of the battery cells inside the battery pack, affecting the overall temperature control effect of the battery pack. In particular, the temperature of the battery cells in the rear area will be higher than that of the front cells, resulting in poor temperature consistency in the battery pack, which in turn affects the performance and service life of the battery.

[0005] (2) Heat sink phenomenon: In the battery packs on the same layer, the temperature of the battery modules in the middle is high, while the temperature of the battery modules on both sides close to the side walls of the battery cabinet is low. For example, when two battery packs are arranged on each layer, the temperature of the internal battery modules in the close parts of the two battery packs is high, while the temperature of the internal battery modules in the far parts is low, resulting in a heat sink phenomenon in the middle of each layer of battery packs. The fluid flow between the layers of battery packs may also cause the occurrence of heat sink phenomenon, which in turn leads to uneven heat dissipation of each module in the system, thereby affecting the stability and safety of the overall energy storage system.

[0006] (3) Uneven flow distribution: In air-cooled heat dissipation systems, the air flow rate in the battery cabinet is usually uneven. Because the air flow is affected by factors such as the battery pack layout and vent design, the cold air flow rate in some areas is faster, while the flow rate in other areas is slower. The uneven flow rate may cause some battery packs to receive too much or too little cooling, further exacerbating the temperature imbalance and reduced system efficiency. Summary of the invention

[0007] The purpose of the present invention is to provide a 3D flow diversion temperature management system for an air-cooled energy storage battery cabinet that can effectively suppress thermal cascade and heat sink phenomena in order to solve the above-mentioned problems.

[0008] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0009] A 3D flow guide temperature management system for an air-cooled energy storage battery cabinet comprises a cabinet body and an air conditioner arranged on one side of the cabinet body, wherein multiple layers of battery packs are arranged in sequence from bottom to top inside the cabinet body, a fan is arranged at the front end of the battery pack, a 3D flow guide cover is arranged on the top of the cabinet body, and a composite flow channel connected to an air outlet of the air conditioner is formed inside the 3D flow guide cover.

[0010] The composite flow channel includes an upper flow channel and a lower flow channel arranged at the lower end of the upper flow channel, and the lower flow channel is composed of a main flow channel and a plurality of secondary flow channels. The main flow channel is used to guide the cold air flow in the upper flow channel to the rear end of the battery pack, and the secondary flow channel is used to guide the cold air flow in the upper flow channel to the side of the battery pack, so that the cold air flow discharged downward from the composite flow channel enters the battery pack from the rear end and the side of the battery pack respectively. During the heat dissipation process of the temperature management system, the air conditioner inputs the cold air flow into the composite flow channel of the 3D air guide cover, and the cold air flow is rectified into the lower flow channel after passing through the upper flow channel. In the lower flow channel, the cold air flow in the main flow channel enters the battery pack from the rear end of the battery pack, and this part of the air flow is drawn out from the front end of the battery pack by the fan; the cold air flow in the secondary flow channel enters the battery pack from the side of the battery pack, and this part of the air flow is drawn out from the front end of the battery pack by the fan. The cold air flow in the secondary flow channel can enhance the heat dissipation effect on the front area of ​​the battery pack and avoid the phenomenon of thermal cascade in the front of the battery pack.

[0011] As a further optimization scheme of the present invention, the battery pack includes a shell and a battery cell arranged inside the shell, the rear end of the shell is provided with an opening one corresponding to the main flow channel, the side of the shell is provided with an opening two corresponding to the secondary flow channel, and the bottom end of the lower flow channel is provided with a flow equalizing plate.

[0012] As a further optimization solution of the present invention, the lower flow channel is arranged close to the rear end of the shell, and the second opening is arranged close to the front end of the shell.

[0013] As a further optimization solution of the present invention, a gap is formed between the rear end and the side of each layer of battery packs and the inner wall of the cabinet, and a gap is formed between adjacent battery packs in each layer of battery packs.

[0014] As a further optimization scheme of the present invention, each layer of battery packs is composed of two battery packs, the secondary flow channel is divided into branch flow channel one, branch flow channel two and branch flow channel three, and branch flow channel two is located between branch flow channel one and branch flow channel three.

[0015] As a further optimization scheme of the present invention, the lower flow channel is in the shape of a "mountain", the width of the branch flow channel 2 is greater than the width of the branch flow channel 1 and the branch flow channel 3, and the length of the branch flow channel 2 is greater than the length of the branch flow channel 1 and the branch flow channel 3

[0016] As a further optimization solution of the present invention, heat insulation cotton is provided inside the cabinet.

[0017] As a further optimization solution of the present invention, a heat sink is provided between two adjacent layers of battery packs.

[0018] As a further optimization scheme of the present invention, the cabinet includes an outer shell and an inner shell fixed inside the outer shell, the battery pack is arranged inside the inner shell, the air conditioner is arranged between the outer shell and the inner shell, and a guide channel is provided between the air outlet of the air conditioner and the upper flow channel.

[0019] The beneficial effects of the present invention are:

[0020] 1) The present invention guides and diverts the cold airflow entering the battery cabinet through the composite flow channel in the 3D air guide cover. Part of the cold airflow enters the battery pack from the rear opening of the battery pack, and the other part enters the battery pack from the side opening of the battery pack. The airflow in the battery pack is then extracted by a fan, thereby improving the overall temperature uniformity of the battery cabinet and extending the service life of the battery.

[0021] 2) The lower flow channel of the composite flow channel of the present invention is close to the rear end of the battery pack, and the opening on the side of the battery pack is close to the front end of the battery pack. The cold air flowing out of the main flow channel of the lower flow channel flows into the battery pack from the rear end of the battery pack, and the cold air flowing out of the secondary flow channel flows into the battery pack from the front middle of the side of the battery pack, which can effectively avoid the thermal cascade phenomenon in the front of the battery pack and further improve the temperature uniformity inside the battery cabinet;

[0022] 3) The secondary flow channel of the present invention is divided into three branch flow channels, the length of the middle branch flow channel is greater than the branch flow channels on both sides, and the middle branch flow channel is relatively wide, which can avoid the heat sink phenomenon of the battery modules in the adjacent parts of the same layer of battery packs, and suppress the flow of fluid between layers through the heat sink plate, so that the cold air flow on the side of the battery pack is easier to flow into the side opening of the battery pack, further suppressing the heat sink of the battery pack and improving the stability and safety of the energy storage system;

[0023] 4) The present invention guides the cold air flow through the upper flow channel, and through the lower flow channel and the flow equalizing plate at its lower end, so that the cold air flow in the lower flow channel is in the shape of a "mountain" and flows toward the battery pack. The cold air flow can smoothly enter the gap between the side wall of the cabinet and the battery pack and the gap in the adjacent battery pack, and smoothly flow into the opening one and the opening two. The cold air flow velocity is moderate and the flow distribution is uniform, avoiding temperature imbalance and reduced system efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the internal structure of the battery pack of the present invention;

[0025] Figure 2 It is a schematic diagram of the split structure of the present invention;

[0026] Figure 3 It is a cross-sectional structural schematic diagram of the present invention;

[0027] Figure 4 It is a schematic diagram of the structure of the current equalizing plate of the present invention;

[0028] Figure 5 It is a schematic diagram of the 3D air deflector structure of the present invention;

[0029] Figure 6 It is a schematic diagram of the secondary flow channel structure of the present invention;

[0030] Figure 7 This is a temperature cloud diagram of the battery cell in the case where no branch flow channel is provided in the present invention;

[0031] Figure 8 It is a temperature cloud diagram of the battery cell under the branch flow channel scheme of the present invention.

[0032] In the figure: 1. cabinet; 2. air conditioner; 3. battery pack; 4. fan; 5. 3D air guide cover; 6. composite flow channel; 7. thermal insulation cotton; 8. heat-proof collector plate; 9. flow guide channel; U, flow equalizing plate; 11. outer shell; 12. inner shell; 31. shell; 32. opening one; 33. opening two; 61. upper flow channel; 62. lower flow channel; 621. main flow channel; 622. secondary flow channel; 622a. branch flow channel one; 622b. branch flow channel two; 622c. branch flow channel three. DETAILED DESCRIPTION

[0033] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0034] Example

[0035] like Figure 1-3 As shown, a 3D flow diversion temperature management system of an air-cooled energy storage battery cabinet includes a cabinet 1 and an air conditioner 2 arranged on one side of the cabinet 1. Multiple layers of battery packs 3 are arranged in sequence from bottom to top inside the cabinet 1. In this embodiment, the number of battery packs 3 in each layer is two. The battery packs 3 in the battery cabinet are neatly stacked into two clusters. There is a vertical air duct between the two clusters of battery packs 3. A vertical air duct is also formed between the side away from the two clusters of battery packs 3 and the side wall of the cabinet 1. A vertical air duct is also formed between the rear ends of the two clusters of battery packs 3 and the side wall of the cabinet 1. A fan 4 is arranged at the front end of the battery pack 3. Figure 3 The dotted line at the front end of the battery pack 3 is used to represent the fan 4 at the front end thereof. A 3D air guide 5 is provided on the top of the cabinet 1, and a composite flow channel 6 communicating with the air outlet of the air conditioner 2 is formed inside the 3D air guide 5.

[0036] The composite flow channel 6 includes an upper flow channel 61 and a lower flow channel 62 provided at the lower end of the upper flow channel 61. Figure 3 , 5 6, the dotted line in the composite flow channel 6 represents the boundary between the upper flow channel 61 and the lower flow channel 62. The lower flow channel 62 is composed of a main flow channel 621 and a plurality of secondary flow channels 622. The main flow channel 621 is used to guide the cold air flow in the upper flow channel 61 to the rear end of the battery pack 3, and the secondary flow channel 622 is used to guide the cold air flow in the upper flow channel 61 to the side of the battery pack 3, so that the cold air flow discharged downward from the composite flow channel 6 enters the battery pack 3 from the rear end and side of the battery pack 3 respectively.

[0037] During the heat dissipation process of the temperature management system, the air conditioner 2 inputs the cold air flow into the composite flow channel 6 of the 3D air guide cover 5, and the cold air flow passes through the upper flow channel 61 and is rectified into the lower flow channel 62. In the lower flow channel 62, the cold air flow in the main flow channel 621 enters the battery pack 3 from the rear end of the battery pack 3, and is drawn out from the front end of the battery pack 3 by the fan 4; the cold air flow in the secondary flow channel 622 enters the battery pack 3 from the side of the battery pack 3, and is drawn out from the front end of the battery pack 3 by the fan 4. The cold air flow in the secondary flow channel 622 can enhance the heat dissipation effect on the front area of ​​the battery pack 3 and avoid the phenomenon of thermal cascade in the front of the battery pack 3. Please refer to Figure 7 and Figure 8 , Figure 7 This is a temperature cloud diagram of the battery cell in the case where the secondary flow channel 622 is not provided in the present invention. Figure 8This is a cloud diagram of the battery cell temperature under the scheme of setting the secondary flow channel 622 of the present invention. It can be seen from the figure that when the secondary flow channel 622 is not set, the maximum temperature of the monitoring point is 36.1°C, the minimum temperature is 27.2°C, and the maximum temperature difference is 8.9°C. When the secondary flow channel 622 is set, the maximum temperature of the monitoring point is 35.2°C, the minimum temperature is 29.4°C, and the maximum temperature difference is 5.8°C. Compared with the traditional temperature management system, the maximum temperature and the maximum temperature difference in the battery cabinet in this embodiment are significantly reduced.

[0038] Specifically, Figure 2-4 As shown, the battery pack 3 includes a shell 31 and a battery cell arranged inside the shell 31. The rear end of the shell 31 is provided with a plurality of openings 32 corresponding to the main flow channel 621, and the side of the shell 31 is provided with a plurality of openings 33 corresponding to the secondary flow channel 622. A flow equalizing plate U is provided at the bottom of the lower flow channel 62. In this embodiment, two upper and lower fans 4 are provided at the front end of each shell 31. In addition, in other embodiments, the number of fans 4 can also be adjusted according to actual needs, for example, only one fan is provided at the front end of the shell 31. The flow equalizing plate U is fixedly arranged at the lower edge of the 3D air guide cover 5, and the shape of the flow equalizing plate U is consistent with the shape of the lower flow channel 62. Figure 2 and Figure 3 The flow equalizing plate U is not shown in the figure. In this embodiment, the 3D flow guide 5 is provided with a flow equalizing plate U at the lower end, and in some other embodiments, when the flow resistance of the 3D flow guide 5 is large enough to achieve the flow equalization function, the setting of the flow equalizing plate U can also be cancelled.

[0039] The air conditioner 2 is arranged in front of the upper flow channel 61, the lower flow channel 62 is arranged near the rear end of the shell 31, and the second opening 33 is arranged near the front end of the shell 31. A gap is formed between the rear end and the side of each layer of battery packs 3 and the inner wall of the cabinet 1, and a gap is formed between adjacent battery packs 3 in each layer of battery packs 3. The above gaps constitute the air ducts on the side and rear end of the battery packs 3. Please refer to Figure 5 and Figure 6 The secondary flow channel 622 is divided into a branch flow channel 1 622a, a branch flow channel 2 622b and a branch flow channel 3 622c, and the branch flow channel 2 622b is located between the branch flow channel 1 622a and the branch flow channel 3 622c. It should be noted that the side surface of the battery pack 3 and its shell 31 in the present invention refers to a pair of vertical end surfaces perpendicular to the front end of the battery pack 3.

[0040] The lower flow channel 62 is in the shape of a "mountain", the width of the branch flow channel 2 622b is greater than the width of the branch flow channel 1 622a and the branch flow channel 3 622c, and the length of the branch flow channel 2 622b is greater than the length of the branch flow channel 1 622a and the branch flow channel 3 622c. The opening rate of the portion corresponding to the flow equalizer U and the branch flow channel 2 622b is higher than the opening rate of the portion corresponding to the branch flow channel 1 622a and the branch flow channel 3 622c. The air conditioner 2 is preferably an Invic air conditioner.

[0041] Through the lower flow channel 62 and the flow equalizing plate U, the cold air flow flows in the lower flow channel 62 in a "mountain" shape to the air ducts between the battery packs 3 and between the battery packs 3 and the cabinet 1, and gradually flows to the inside of each layer of the battery packs 3. During this period, the cold air flow can smoothly enter the air duct in the cabinet 1 and smoothly flow into the opening 1 32 and the opening 2 33. The cold air flow velocity is moderate and the flow distribution uniformity is good, avoiding temperature imbalance and reduced system efficiency.

[0042] And because the second opening 33 is arranged near the front end of the battery pack 3, to be precise, a group of second openings 33 on the side of the battery pack 3 are respectively located in the middle and front parts in the length direction of the shell 31 of the battery pack 3. The cold airflow in the secondary flow channel 622 can quickly reach the middle and front areas inside the battery pack 3, and can directly cool down the front areas of the battery pack 3, thereby preventing the rear part of the battery pack 3 from being overcooled and the front part from being overheated.

[0043] Taking into account the possibility of heat sink between the two battery packs 3, the secondary flow channel 622 is further improved so that the width and length of the middle branch flow channel 2 622b are increased, and the opening rate of the corresponding part of the flow equalizing plate U is increased, which can effectively suppress the heat sink between the two battery packs 3.

[0044] Furthermore, a heat-insulating cotton 7 is provided in the inner interlayer of the cabinet body 1, and the thickness of the heat-insulating cotton 7 is preferably 30 mm, so as to isolate the internal and external heat exchange of the battery cabinet. An anti-heat sink plate 8 is provided between two adjacent layers of battery packs 3. The anti-heat sink plate 8 is specifically arranged between the front panels of the shells 31 of two vertically adjacent battery packs 3. The sizes of each battery pack 3 are consistent, the top wall and the bottom wall of the shell 31 of the same cluster of battery packs 3 are aligned, and the edge of the heat-insulating cotton 7 is aligned with the edge of the top wall of the shell 31. The anti-heat sink plate 8 between two adjacent layers of battery packs 3 is used to suppress the inter-layer fluid flow between each layer of battery packs 3. Thereby further improving the inhibitory effect on the heat sink phenomenon in the battery cabinet and improving the stability and safety of the energy storage system.

[0045] In addition, the cabinet 1 includes an outer shell 11 and an inner shell 12 fixed inside the outer shell 11, the battery pack 3 is arranged inside the inner shell 12, the air conditioner 2 is arranged between the outer shell 11 and the inner shell 12, and a guide channel 9 is provided between the air outlet of the air conditioner 2 and the upper flow channel 61. An interlayer is formed between the outer shell 11 and the inner shell 12, and the heat insulation cotton 7 is arranged in the interlayer between the outer shell 11 and the inner shell 12 to isolate the internal and external heat exchange of the battery cabinet. In addition, in some other embodiments, an interlayer can also be provided in the side wall, top wall, and bottom wall of the outer shell 11, and the heat insulation cotton 7 can be provided in the interlayer. The 3D air deflector 5 is fixed below the top wall of the inner shell 12, and the inner shell 12 closes the top of the 3D air deflector 5 through its top wall. The battery pack 3 at the bottom is fixedly arranged on the bottom wall of the inner shell 12, the air conditioner 2 is fixedly installed on the inner side wall of the outer shell 11, the guide channel 9 runs through the inner shell 12, and the two ends of the guide channel 9 are respectively fixedly connected to the air outlet of the air conditioner 2 and the air inlet of the 3D air guide cover 5, and an air outlet is arranged at the front end of the inner shell 12. The airflow drawn out by the fan 4 at the front end of the battery pack 3 enters the return air outlet of the air conditioner 2 for cooling, and re-enters the interior of the battery cabinet inner shell 12 through the air outlet of the air conditioner 2.

[0046] In addition, in some other embodiments, only the outer shell 11 may be provided without the inner shell 12. In this case, the 3D air duct 5 is fixedly provided below the top wall of the outer shell 11, the battery pack 3 of the lowest layer is fixedly provided on the bottom wall of the outer shell 11, and the air inlet of the 3D air duct 5 may also be directly fixedly provided at the air outlet of the air conditioner 2 to omit the air guide channel 9. The air conditioner 2 may also be provided outside the outer shell 11, as long as the air outlet of the air conditioner 2 can be connected to the air inlet of the 3D air duct 5, and the air return port of the air conditioner 2 can be connected to the air outlet of each fan 4.

[0047] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A 3D flow guide temperature management system for an air-cooled energy storage battery cabinet, comprising a cabinet (1) and an air conditioner (2) arranged on one side of the cabinet (1), wherein multiple layers of battery packs (3) are arranged in sequence from bottom to top inside the cabinet (1), characterized in that: A fan (4) is provided at the front end of the battery pack (3), and a 3D flow guide cover (5) is provided at the top of the cabinet body (1), and a composite flow channel (6) communicating with the air outlet of the air conditioner (2) is formed inside the 3D flow guide cover (5); The composite flow channel (6) includes an upper flow channel (61) and a lower flow channel (62) provided at the lower end of the upper flow channel (61). The lower flow channel (62) is composed of a main flow channel (621) and a plurality of sub-flow channels (622). The main flow channel (621) is used to direct the cold air flow in the upper flow channel (61) to the rear end of the battery pack (3), and the sub-flow channels (622) are used to direct the cold air flow in the upper flow channel (61) to the side of the battery pack (3), so that the cold air flow discharged downward from the composite flow channel (6) enters the inside of the battery pack (3) from the rear end and the side of the battery pack (3) respectively.

2. The 3D flow-guiding temperature management system according to claim 1, characterized in that: The battery pack (3) includes a housing (31) and battery cells provided inside the housing (31). An opening one (32) corresponding to the main flow channel (621) is provided at the rear end of the housing (31), and an opening two (33) corresponding to the sub-flow channel (622) is provided on the side of the housing (31). A flow equalizing plate is provided at the bottom end of the lower flow channel (62).

3. The 3D flow-guiding temperature management system according to claim 2, characterized in that: The lower flow channel (62) is arranged close to the rear end of the housing (31), and the opening two (33) is arranged close to the front end of the housing (31).

4. The 3D flow-guiding temperature management system according to claim 3, characterized in that: A gap is formed between the rear end and the side of each layer of the battery pack (3) and the inner side wall of the cabinet body (1), and a gap is formed between adjacent battery packs (3) in each layer of the battery pack (3).

5. The 3D flow-guiding temperature management system according to claim 4, characterized in that: Each layer of the battery pack (3) is composed of two battery packs (3). The sub-flow channels (622) are divided into a branch flow channel one (622a), a branch flow channel two (622b), and a branch flow channel three (622c), and the branch flow channel two (622b) is located between the branch flow channel one (622a) and the branch flow channel three (622c).

6. The 3D flow-guiding temperature management system according to claim 5, characterized in that: The lower flow channel (62) is in a "mountain" shape. The width of the branch flow channel two (622b) is greater than the widths of the branch flow channel one (622a) and the branch flow channel three (622c), and the length of the branch flow channel two (622b) is greater than the lengths of the branch flow channel one (622a) and the branch flow channel three (622c).

7. The 3D flow-guiding temperature management system according to claim 1, characterized in that: Heat insulation cotton (7) is provided inside the cabinet body (1).

8. The 3D flow-guiding temperature management system according to claim 1, characterized in that: A heat sink prevention plate (8) is provided between adjacent two layers of the battery packs (3).

9. The 3D flow-guiding temperature management system according to claim 1, characterized in that: The cabinet body (1) includes an outer shell (11) and an inner shell (12) fixedly arranged inside the outer shell (11). The battery pack (3) is arranged inside the inner shell (12), the air conditioner (2) is arranged between the outer shell (11) and the inner shell (12), and a flow guide channel (9) is provided between the air outlet of the air conditioner (2) and the upper flow channel (61).

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