Battery pack gluing device

Abstract

The utility model relates to the technical field of batteries, and discloses a battery pack gluing device. The battery pack gluing device comprises a workbench, a first detection unit, a gluing mechanism and a controller, the workbench is suitable for placing a lower shell containing a battery cell, the first detection unit is used for detecting the height of a sealing face of the lower shell, the gluing mechanism comprises a mechanical arm, a gluing assembly and a second detection unit, and the gluing assembly and the second detection unit are arranged on the mechanical arm. The mechanical arm is used for driving the gluing assembly and the second detection unit to move along a gluing area of the battery cell, the second detection unit is used for detecting the height of the gluing area, and the controller is configured to receive detection information of the first detection unit and the second detection unit and control the battery cell according to the height difference between the sealing surface and the gluing area. And the gluing assembly is controlled to adjust the gluing amount based on the height difference. The glue spreading amount of the glue spreading assembly is accurately controlled through the controller according to the calculated height difference, and it is ensured that glue is evenly distributed in areas with different heights.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field, concretely relates to battery pack rubber coating device. BACKGROUND

[0002] The rapid rise of the electric vehicle industry has driven unprecedented demand for high-performance battery packs. As the core of the next generation of battery integration technology, CTC (Battery Chassis Integration Technology) abandons traditional battery modules and packaging methods, and directly installs the battery cell on the frame, thereby maximizing the use of space and lightweighting the vehicle.

[0003] In the prior art, CTC (Battery Chassis Integration Technology) is to first install the battery cell into the lower shell. After that, the rubber coating area on the top surface of the battery cell is subjected to rubber coating operation. After the rubber coating is completed, the upper shell cover is arranged on the lower shell to achieve sealing. However, because the battery cell is first installed into the lower shell during the operation, the flatness of the rubber coating area of the battery cell is inconsistent, which easily causes the rubber coating thickness of the local rubber coating area to be uneven, and further causes the flatness of the surface of the upper shell to be poor. SUMMARY

[0004] Therefore, the utility model provides a battery pack rubber coating device to solve the problem of inconsistent flatness of the rubber coating area of the battery cell.

[0005] The utility model provides a battery pack rubber coating device, comprising:

[0006] A workbench is adapted to place a lower shell containing a battery cell.

[0007] A first detection unit is used to detect the height of the sealing surface of the lower shell.

[0008] A rubber coating mechanism comprises a mechanical arm, a rubber coating assembly arranged on the mechanical arm, and a second detection unit. The mechanical arm is used to drive the rubber coating assembly and the second detection unit to move along the rubber coating area of the battery cell. The second detection unit is used to detect the height of the rubber coating area.

[0009] A controller is electrically connected to the first detection unit and the rubber coating mechanism, respectively. The controller is configured to receive the detection information of the first detection unit and the second detection unit, and to control the rubber coating assembly to adjust the amount of rubber coating based on the height difference between the sealing surface and the rubber coating area.

[0010] Beneficial effects: this battery package gluing device, when gluing the battery cell, first needs to place the lower shell with the battery cell on the workbench. Then, the first detection unit detects the sealing surface height of the lower shell accurately and transmits the detection information to the controller in time. Then, the mechanical arm in the gluing mechanism drives the second detection unit to move in the gluing area of the battery cell. In this process, the second detection unit detects the height of the gluing area and accurately sends the corresponding height information to the controller.

[0011] After receiving the detection information from the first detection unit and the second detection unit, the controller processes the data and accurately calculates the height difference between the sealing surface and the gluing area. Then, the controller controls the gluing amount of the gluing assembly according to the calculated height difference. It realizes accurate gluing control, can ensure that the glue is evenly distributed in areas of different heights, guarantees the gluing quality, and avoids the problem of uneven gluing thickness caused by inconsistent flatness of the gluing area.

[0012] In an alternative embodiment, a rack is further included, the rack comprising a base and a mounting frame connected to the base, the mounting frame being located above the workbench, and the first detection unit being movably arranged on the mounting frame by a driving member and being adapted to move along the edge of the sealing surface.

[0013] Beneficial effects: setting the mounting frame above the workbench and driving the first detection unit along the edge of the sealing surface by the driving member can comprehensively detect the height of the entire sealing surface of the lower shell. Compared with the fixed position detection method, the height information of different positions of the sealing surface can be obtained, avoiding the problem of missed height difference caused by local detection, and providing a more comprehensive and accurate data basis for subsequent accurate gluing.

[0014] By comprehensively detecting the height of the sealing surface, the controller can control the gluing amount of the gluing assembly according to more accurate height information. For the areas with inconsistent sealing surface height, the gluing amount can be adjusted accordingly, thereby improving the sealing effect between the upper shell and the lower shell.

[0015] In an alternative embodiment, the controller is electrically connected with the driving member, and the controller is used to control the driving member to drive the first detection unit to move, and then control the mechanical arm to drive the second detection unit and the gluing assembly to move.

[0016] Beneficial effects: the controller can accurately control the action sequence of the first detection unit and the gluing assembly. The controller first ensures that the first detection unit completes the comprehensive and accurate detection of the height of the sealing surface, transmits the data to the controller for analysis and processing, and then instructs the mechanical arm to drive the gluing assembly to start gluing, ensuring that the gluing process is based on accurate detection data, thereby improving the precision and quality of gluing.

[0017] In an optional embodiment, the mounting frame is arranged in parallel with the workbench.

[0018] Beneficial effect: arranging the mounting frame in parallel with the workbench can keep the distance between the first detection unit and the sealing surface relatively stable during movement, thus obtaining accurate height information and providing a reliable data basis for subsequent glue application control.

[0019] In an optional embodiment, the glue application mechanism and the rack are respectively arranged on opposite sides of the workbench.

[0020] Beneficial effect: arranging the glue application mechanism and the rack on opposite sides of the workbench can more reasonably utilize space, avoid space congestion that may be caused when they are arranged on the same side, make the layout of the entire glue application device on the workbench more open, and effectively prevent the glue application mechanism from colliding with or interfering with the rack and components thereon during work.

[0021] In an optional embodiment, the height of the mounting frame is greater than the height of the mechanical arm.

[0022] Beneficial effect: arranging the mounting frame with a height greater than that of the mechanical arm can ensure that the mechanical arm does not collide with the mounting frame and components thereon when performing glue application work and moving the glue application assembly and the second detection unit, provide sufficient space for movement of the mechanical arm, and ensure the safety and stability of equipment operation.

[0023] In an optional embodiment, the second detection unit is arranged adjacent to the glue application assembly, and the bottom end of the second detection unit is in the same plane as the bottom end of the glue application assembly.

[0024] Beneficial effect: arranging the second detection unit adjacent to the glue application assembly and in the same plane as the bottom end of the glue application assembly can detect the height of the glue application area in real time while glue application. The second detection unit can immediately detect and transmit information to the controller, and the controller can quickly adjust the glue application amount of the glue application assembly according to the height difference, ensuring uniform distribution of glue in areas of different heights and improving glue application quality.

[0025] In an optional embodiment, a work computer is further included, the work computer is electrically connected with the first detection unit and the second detection unit respectively, and the work computer is used for receiving and displaying detection information of the first detection unit and the second detection unit.

[0026] Beneficial effects: The industrial computer can receive the detection information of the first detection unit and the second detection unit in real time, and display the data in an intuitive manner. The operator can observe the changes of the lower shell sealing surface height and the glue application area height in real time on the screen of the industrial computer, which helps to find abnormal conditions of the battery cell before and during glue application, such as whether there is a large flatness error in the sealing surface, whether the glue application area height changes suddenly, etc., so that measures can be taken quickly to adjust or repair, and the glue application quality is ensured.

[0027] In an alternative embodiment, a display and a shooting unit electrically connected to the display are further included, the shooting unit is used to collect glue application image information of the glue application assembly, and the display displays a glue application picture based on the received glue application image information.

[0028] Beneficial effects: The shooting unit collects glue application image information of the glue application assembly and displays a glue application picture in real time through the display, so that the operator can intuitively see the actual situation of glue application, which helps to find problems in the glue application process in time and improves product quality.

[0029] In an alternative embodiment, an independent power supply is further included, and the independent power supply is electrically connected to the first detection unit, the glue application mechanism and the controller respectively.

[0030] Beneficial effects: The independent power supply can continuously provide power for the first detection unit, the glue application mechanism and the controller. For the battery pack glue application which has high requirements on process precision and continuity, the independent power supply can provide relatively pure and stable power for the glue application device, reduce the influence of external power supply interference on the equipment, ensure the normal operation of the equipment, and improve the stability and reliability of production. BRIEF DESCRIPTION OF DRAWINGS

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

[0032] Figure 1 It is a principle schematic diagram of a battery pack glue application device of an embodiment of the present application.

[0033] Figure 2 It is a top view of a battery pack glue application device of an embodiment of the present application.

[0034] MARKED DESCRIPTION OF DRAWINGS:

[0035] 1, workbench; 2, lower shell; 201, battery cell; 2011, gluing area; 202, sealing surface; 3, first detection unit; 4, gluing mechanism; 401, mechanical arm; 4011, gluing assembly; 4012, second detection unit; 5, rack; 501, base; 502, mounting bracket; 6, industrial computer; 7, display; 8, independent power supply. DETAILED DESCRIPTION

[0036] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0037] In the related art, CTC (battery chassis integration technology) is to first put the battery cell into the lower shell. Then, the gluing operation is performed on the gluing area on the top surface of the battery cell. After the gluing is completed, the upper shell cover is arranged on the lower shell to realize sealing. However, because the battery cell is first put into the lower shell in the operation process, the flatness of the gluing area of the battery cell is inconsistent, which easily causes the local gluing thickness of the gluing area to be uneven, and further causes the flatness of the surface of the upper shell to be poor.

[0038] To solve the above technical problem, the embodiments of the present application are described below in combination with Figures 1 to 2 .

[0039] According to the embodiments of the present application, on the one hand, as shown in Figure 1 and Figure 2 , a battery pack gluing device is provided, which comprises a workbench 1, a first detection unit 3, a gluing mechanism 4 and a controller (not shown in the figure).

[0040] Specifically, as shown in Figure 1 and Figure 2 , the lower shell 2 is placed on the workbench 1, and the battery cell 201 is arranged in the lower shell 2. The battery cell 201 can be arranged in multiple, and is arranged in multiple mounting grooves arranged on the lower shell 2.

[0041] Specifically, as shown in Figure 1 and Figure 2 , the first detection unit 3 is used for detecting the height of the sealing surface 202 of the lower shell 2.

[0042] Specifically, as shown in Figure 1 and Figure 2 , the second detection unit 4012 is used for detecting the height of the gluing area 2011 of the battery cell 201.As shown, the gluing mechanism 4 comprises a mechanical arm 401, a gluing assembly 4011 and a second detection unit 4012. The gluing assembly 4011 and the second detection unit 4012 are installed on the mechanical arm 401, the mechanical arm 401 is used to drive the gluing assembly 4011 and the second detection unit 4012 to move, and the gluing assembly 4011 and the second detection unit 4012 move along the gluing area 2011 of the battery cell 201. The second detection unit 4012 is used to detect the height of the gluing area 2011 of the battery cell 201.

[0043] Specifically, as shown in the figure, Figure 1 The controller (not shown in the figure) is electrically connected with the first detection unit 3 and the gluing mechanism 4 respectively, and is configured to receive the detection information of the first detection unit 3 and the second detection unit 4012, and control the gluing assembly 4011 to adjust the gluing amount based on the height difference according to the height difference between the sealing surface 202 and the gluing area 2011.

[0044] This battery pack gluing device, when gluing the battery cell 201, first needs to place the lower shell 2 containing the battery cell 201 stably on the workbench 1. Then, the first detection unit 3 detects the height of the sealing surface 202 of the lower shell 2 accurately and timely, and transmits the information obtained by detection to the controller. Then, the mechanical arm 401 of the gluing mechanism 4 drives the second detection unit 4012 to move on the gluing area 2011 of the battery cell 201. In this process, the second detection unit 4012 detects the height of the gluing area 2011 and sends the corresponding height information to the controller.

[0045] After receiving the detection information from the first detection unit 3 and the second detection unit 4012, the controller processes the data, accurately calculates the height difference between the sealing surface 202 and the gluing area 2011. Then, the controller controls the gluing amount of the gluing assembly 4011 according to the calculated height difference. The height-accurate gluing control is realized, which can ensure that the glue is uniformly distributed in the areas with different heights, ensure the gluing quality, and avoid the problem of uneven gluing thickness caused by the inconsistency of the flatness of the gluing area 2011.

[0046] Specifically, the size of the workbench 1 should be larger than the size of the lower shell 2, so as to ensure that the lower shell 2 is stably placed on the workbench 1, and the workbench 1 can be selected in any existing shape. In the embodiment of the present application, the shape and size of the workbench 1 are not limited.

[0047] Specifically, the first detection unit 3 and the second detection unit 4012 can be selected from laser displacement sensors, ultrasonic sensors or capacitive displacement sensors, etc. In the embodiment of the present application, the types of the first detection unit 3 and the second detection unit 4012 are not limited.

[0048] Specifically, the glue applying assembly 4011 can be selected from a glue gun, an automatic glue applying valve, a peristaltic pump type glue applying device, etc. In the embodiments of the present application, the type of the glue applying assembly 4011 is not specifically limited.

[0049] Specifically, the mechanical arm 401 can be selected from any existing mechanical hand. In the embodiments of the present application, the type of the mechanical arm 401 is not specifically limited.

[0050] Specifically, the controller can be an existing controller such as a PLC (programmable logic controller), a microcontroller or a computer control system. In the embodiments of the present application, the type of the controller is not specifically limited.

[0051] In one embodiment, as shown in Figure 1 The rack 5 includes a base 501 and a mounting frame 502, the mounting frame 502 is connected with the base 501, and the mounting frame 502 is arranged above the workbench 1. The first detection unit 3 is connected with the driving member, and the first detection unit 3 is movably arranged on the mounting frame 502 through the driving member. The driving member drives the first detection unit 3 to move along the edge of the sealing surface 202.

[0052] Arranging the mounting frame 502 above the workbench 1 and driving the first detection unit 3 to move along the edge of the sealing surface 202 can comprehensively detect the height of the entire sealing surface 202 of the lower shell 2. Compared with the detection mode of the fixed position, the height information of different positions of the sealing surface 202 can be obtained, and the problem of the height difference that may be missed due to local detection is avoided, thereby providing a more comprehensive and accurate data basis for subsequent accurate glue applying.

[0053] By comprehensively detecting the height of the sealing surface 202, the controller can control the glue applying amount of the glue applying assembly 4011 according to the more accurate height information. For the area with inconsistent height of the sealing surface 202, the glue applying amount can be adjusted accordingly, thereby improving the sealing effect between the upper shell and the lower shell 2.

[0054] Specifically, the driving member can be selected from any existing driving structure such as a linear motor, a synchronous belt and a motor combination. In the embodiments of the present application, the type of the driving member is not specifically limited.

[0055] Specifically, the mounting frame 502 can be arranged in any existing shape. For example, the shape of the mounting frame 502 can be similar to the shape of the sealing surface 202 of the lower shell 2, so as to facilitate the first detection unit 3 to detect along the edge of the sealing surface 202. In the embodiments of the present application, the shape of the mounting frame 502 is not specifically limited.

[0056] In one embodiment, as shown in Figure 1As shown, the controller is electrically connected with the driving member, and the controller is configured to control the driving member to drive the first detection unit 3 to move, and then control the mechanical arm 401 to drive the second detection unit 4012 and the glue applying assembly 4011 to move.

[0057] The controller can accurately control the action sequence of the first detection unit 3 and the glue applying assembly 4011. The controller first ensures that the first detection unit 3 completes the comprehensive and accurate detection of the height of the sealing surface 202, and transmits the data to the controller for analysis and processing, and then instructs the mechanical arm 401 to drive the glue applying assembly 4011 to start glue applying, so as to ensure that the glue applying process is based on accurate detection data, thereby improving the precision and quality of glue applying.

[0058] In one embodiment, as shown in Figure 1 The mounting rack 502 is arranged in parallel with the workbench 1.

[0059] Arranging the mounting rack 502 in parallel with the workbench 1 can keep the distance between the first detection unit 3 and the sealing surface 202 relatively stable during movement, so as to obtain accurate height information and provide a reliable data basis for subsequent glue applying control.

[0060] In one embodiment, as shown in Figure 1 The glue applying mechanism 4 and the rack 5 are arranged on opposite sides of the workbench 1, respectively.

[0061] Arranging the glue applying mechanism 4 and the rack 5 on opposite sides of the workbench 1 can more reasonably utilize the space, avoid space congestion that may be caused when they are arranged on the same side, make the layout of the entire glue applying device on the workbench 1 more open, and effectively prevent the glue applying mechanism 4 from colliding with or interfering with the rack 5 and components (such as the first detection unit 3 and its driving member) thereon during work.

[0062] In one embodiment, as shown in Figure 1 The height of the mounting rack 502 is greater than the height of the mechanical arm 401.

[0063] The height of the mounting rack 502 is greater than the height of the mechanical arm 401, which can ensure that the mechanical arm 401 does not collide with the mounting rack 502 and components (such as the first detection unit 3 and its driving member) thereon during glue applying operation and movement of the glue applying assembly 4011 and the second detection unit 4012, provide sufficient space for movement of the mechanical arm 401, and ensure the safety and stability of equipment operation.

[0064] For example, if the height of the mounting rack 502 is insufficient, the movement range of the mechanical arm 401 during work is large, and the mechanical arm 401 may collide with the mounting rack 502 during movement, which not only damages the equipment, but also causes interruption of glue applying operation and affects production efficiency.

[0065] In one embodiment, as shown in Figure 1 The second detection unit 4012 is arranged adjacent to the glue applying assembly 4011, and the bottom end of the second detection unit 4012 is in the same plane as the bottom end of the glue applying assembly 4011.

[0066] The second detection unit 4012 is arranged adjacent to the glue applying assembly 4011 and the bottom end is in the same plane, which can detect the height of the glue applying area 2011 in real time while applying glue. The second detection unit 4012 can immediately detect and transmit information to the controller, and the controller can quickly adjust the glue applying amount of the glue applying assembly 4011 according to the height difference, so as to ensure that the glue is uniformly distributed in areas of different heights and improve the glue applying quality.

[0067] Compared with the design that the detection unit and the glue applying assembly 4011 are separated far away, there is no need for complex mechanical structure to adjust the relative position relationship between them, which reduces the number of parts of the equipment, reduces the manufacturing cost and maintenance difficulty of the equipment. At the same time, the control logic is also simpler, and the controller only needs to directly control the glue applying assembly 4011 at the same position according to the height information fed back by the adjacent second detection unit 4012 in real time, without the need for complex coordinate conversion or position matching calculation, which improves the response speed and stability of the control system.

[0068] In one embodiment, as shown in Figure 1 The industrial computer 6 is electrically connected with the first detection unit 3 and the second detection unit 4012 respectively, and the industrial computer 6 is used for receiving and displaying the detection information of the first detection unit 3 and the second detection unit 4012.

[0069] The industrial computer 6 can receive the detection information of the first detection unit 3 and the second detection unit 4012 in real time, and display these data in an intuitive way. The operator can observe the changes of the height of the sealing surface 202 of the lower shell 2 and the height of the glue applying area 2011 in real time on the screen of the industrial computer 6, which helps to find abnormal conditions of the battery cell 201 module before and during glue applying, such as whether there is a large flatness error in the sealing surface 202, whether the height of the glue applying area 2011 changes suddenly, etc., so that measures can be taken quickly to adjust or repair, and the glue applying quality is ensured.

[0070] In one embodiment, as shown in Figure 1 The display 7 and the shooting unit are further included, the shooting unit is electrically connected with the display 7, the shooting unit is used for collecting the glue applying image information of the glue applying assembly 4011, and the display 7 displays the glue applying picture based on the received glue applying image information.

[0071] The shooting unit collects the gluing image information of the gluing assembly 4011 and displays the gluing picture in real time through the display 7, so that the operator can intuitively see the actual situation of gluing, problems in the gluing process can be found in time, and the product quality is improved.

[0072] In one embodiment, as Figure 1 indicated, an independent power supply 8 is further included, and the independent power supply 8 is electrically connected with the first detection unit 3, the gluing mechanism 4 and the controller respectively.

[0073] The independent power supply 8 can continuously provide power for the first detection unit 3, the gluing mechanism 4 and the controller. For the battery cell 201 module gluing which is a production process with high requirements on process precision and continuity, the independent power supply 8 can provide relatively pure and stable power for the gluing device, reduce the influence of external power supply interference on the equipment, ensure the normal operation of the equipment, and improve the stability and reliability of production.

[0074] The working principle of the battery pack gluing device in the embodiment is described as follows:

[0075] Firstly, the lower shell 2 containing the battery cell 201 is stably placed on the workbench 1.

[0076] Then, the first detection unit 3 detects the height of the sealing surface 202 of the lower shell 2 and transmits the information to the controller in real time.

[0077] Then, the mechanical arm 401 of the gluing mechanism 4 drives the second detection unit 4012 to move in the gluing area 2011 of the battery cell 201. During the movement, the second detection unit 4012 continuously detects the height of the gluing area 2011 and sends the height information to the controller.

[0078] After receiving the detection information of the first detection unit 3 and the second detection unit 4012, the controller processes the data, calculates the height difference between the sealing surface 202 and the gluing area 2011, and accurately controls the gluing amount of the gluing assembly 4011 according to the height difference.

[0079] Although the embodiments of the present application are described in combination with the drawings, various modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery pack gumming device, characterized by, The application relates to a battery cell sealing surface height detection and glue coating device. The device comprises a workbench for placing a lower shell containing a battery cell; a first detection unit for detecting the height of a sealing surface of the lower shell; a glue coating mechanism comprising a mechanical arm and a glue coating assembly and a second detection unit arranged on the mechanical arm, the mechanical arm being used for driving the glue coating assembly and the second detection unit to move along a glue coating area of the battery cell, and the second detection unit being used for detecting the height of the glue coating area; and a controller electrically connected with the first detection unit and the glue coating mechanism, respectively, the controller being configured to receive detection information of the first detection unit and the second detection unit and control the glue coating assembly to adjust a glue coating amount based on a height difference between the sealing surface and the glue coating area. The device further comprises a rack comprising a base and a mounting rack connected with the base, the mounting rack being located above the workbench, and the first detection unit being movably arranged on the mounting rack and adapted to move along the edge of the sealing surface through a driving member. The controller is electrically connected with the driving member, and the controller is used for controlling the driving member to drive the first detection unit to move and then controlling the mechanical arm to drive the second detection unit and the glue coating assembly to move. The mounting rack is arranged in parallel with the workbench.

2. The battery pack gumming device according to claim 1, wherein, The glue coating mechanism and the rack are respectively located on opposite sides of the workbench.

3. The battery pack gumming device according to claim 2, wherein, The height of the mounting rack is greater than the height of the mechanical arm.

4. The battery pack gumming device according to claim 2, wherein The second detection unit is arranged adjacent to the glue coating assembly, and the bottom end of the second detection unit is located in the same plane as the bottom end of the glue coating assembly.

5. The battery pack gumming device of claim 2, wherein, The device further comprises an industrial computer electrically connected with the first detection unit and the second detection unit, respectively, and the industrial computer is used for receiving and displaying the detection information of the first detection unit and the second detection unit.

6. The battery pack gumming device of claim 2, wherein, The device further comprises a display and a shooting unit electrically connected with the display, the shooting unit being used for collecting glue coating image information of the glue coating assembly, and the display being used for displaying a glue coating picture based on the received glue coating image information.

7. The battery pack gumming device according to any one of claims 1 to 6, characterized in that, The device further comprises an independent power supply electrically connected with the first detection unit, the glue coating mechanism and the controller, respectively.

8. The battery pack gumming device according to any one of claims 1 to 6, characterized in that, ​ 9. The battery pack gumming device according to any one of claims 1 to 6, characterized in that, ​ 10. The battery pack gumming device according to any one of claims 1 to 6, characterized in that, ​

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