Lithium battery core package hot-pressing assembly

Abstract

The utility model relates to battery production equipment technical field discloses a lithium battery core package hot pressing assembly, including hot pressing plate and coaming: two hot pressing plates are along the first direction interval setting, two hot pressing plates can butt in lithium battery core package along the first direction two sides of opposite, to carry out hot pressing to lithium battery core package, coaming is located between two hot pressing plates, and coaming surrounds the circumference of lithium battery core package in annular structure. The utility model discloses a lithium battery core package hot pressing assembly can improve the heating rate of lithium battery core package, reduce lithium battery core package surface and the difference of central hot pressing effect, reduce the probability of the appearance surface overpressure and the middle layering phenomenon.

Description

Technical Field

[0001] This utility model relates to the field of battery production equipment technology, and in particular to a lithium battery cell pack hot pressing assembly. Background Technology

[0002] In the lithium battery production process, hot pressing is used to shape the lithium battery cell pack. A conventional lithium battery hot press has two spaced-apart hot press plates. The cell pack is placed on the lower hot press plate, so that one large surface of the cell pack is in contact with it. The hot press then drives the upper hot press plate downwards, bringing it into contact with the other large surface of the cell pack. After setting the temperature, pressure, and time, the hot press heats and presses down. During the hot pressing process, both the upper and lower large surfaces of the cell pack come into contact with the hot press plates. During heating, the heat transfer of the cell pack is solid-phase heat transfer. The temperature is highest at the contact point between the cell pack and the hot press plates, and the temperature gradually rises in the middle of the cell pack as time progresses.

[0003] In actual production, factors such as production efficiency and prevention of surface overpressure must be considered. If the hot-pressing time is insufficient to completely bond the middle part of the core pack, the surface electrodes of the core pack will have strong adhesion to the separator (potentially leading to overpressure), while the middle electrodes of the core pack will not bond tightly to the separator (i.e., delamination). Overpressure in the core pack can cause separator pores, leading to lithium plating during battery charging and discharging (blocking lithium ion transport). Delamination can result in excessively thick core packs and electrode displacement during charging and discharging, significantly impacting the thickness and safety of the finished battery cell. Utility Model Content

[0004] The purpose of this utility model embodiment is to provide a lithium battery cell pack hot pressing assembly, which can improve the heating rate of the lithium battery cell pack, reduce the heating time in the middle of the lithium battery cell pack, thereby reducing the hot pressing time, reducing the difference in hot pressing effect between the surface and the middle of the lithium battery cell pack, and reducing the probability of surface over-pressure and middle delamination.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A lithium battery cell pack hot-pressing assembly is provided, comprising:

[0007] Two hot press plates are arranged at a distance along a first direction, and the two hot press plates can abut against two opposite sides of the lithium battery cell pack along the first direction to hot press the lithium battery cell pack.

[0008] A surrounding panel is located between the two hot-pressing plates and is arranged in a ring around the outer periphery of the lithium battery cell pack.

[0009] As a further embodiment of the lithium battery cell pack hot-pressing assembly, the enclosure is provided with a plurality of heat-conducting holes facing the outer periphery of the lithium battery cell pack.

[0010] As a further embodiment of the lithium battery cell pack hot-pressing assembly, the inner wall of the enclosure is provided with several connecting grooves, the openings of the connecting grooves are directly opposite the outer periphery of the lithium battery cell pack, and the heat-conducting holes are connected to the connecting grooves.

[0011] As a further embodiment of the lithium battery cell pack hot-pressing assembly, the enclosure includes four side plates, which are connected in sequence to form an annular rectangular structure. At least one side plate is provided with the heat-conducting holes and the connecting grooves. The heat-conducting holes on each side plate are distributed in n rows by m columns. The inner wall of the side plate is provided with n connecting grooves spaced apart along the first direction. Each row of heat-conducting holes on each side plate is connected by a corresponding connecting groove; where n≥1 and m≥1.

[0012] As a further embodiment of the lithium battery cell pack hot-pressing assembly, each of the side plates is provided with the heat-conducting hole and the connecting groove, and the connecting grooves at the same height on the inner walls of two connected side plates are connected.

[0013] As a further embodiment of the hot-pressing assembly of lithium battery cell packs, the inner wall of the enclosure is bonded to the outer periphery of the hot-pressed lithium battery cell pack.

[0014] As a further embodiment of the hot-pressing assembly of lithium battery cell packs, the dimension of the enclosure along the first direction is not greater than the dimension of the hot-pressed lithium battery cell pack along the first direction.

[0015] As a further embodiment of the lithium battery cell pack hot-pressing assembly, the length of the surrounding plate extends along a second direction, the width of the surrounding plate extends along a third direction, the distance between two opposite side plates of the surrounding plate along the second direction is L1, and the dimension of the lithium battery cell pack before hot pressing along the second direction is L2, L1-L2=1~5mm; the distance between two opposite side plates of the surrounding plate along the third direction is K1, and the dimension of the lithium battery cell pack before hot pressing along the third direction is K2, K1-K2=1~5mm, and the first direction, the second direction, and the third direction are perpendicular to each other; and / or,

[0016] The dimension of the enclosure along the first direction is H1, and the dimension of the lithium battery cell pack along the first direction before hot pressing is H2, where H1-H2=1~5mm.

[0017] As a further embodiment of the lithium battery cell pack hot-pressing assembly, the enclosure is provided with a clearance opening for the tabs of the lithium battery cell pack to pass through.

[0018] As a further embodiment of the lithium battery cell pack hot-pressing assembly, the clearance opening is located at the end of the enclosure along the first direction.

[0019] Beneficial effects:

[0020] This invention features a surrounding plate positioned between two hot-pressing plates. The surrounding plate, in a ring shape, encircles the outer perimeter of the lithium battery cell pack. When the hot-pressing equipment is activated, driving the hot-pressing plates to hot-press the lithium battery cell pack, the surrounding plate provides insulation during the hot-pressing process, reducing the heat dissipated from the hot-pressing plates into the air. This reduces the heating time in the center of the lithium battery cell pack, shortens the hot-pressing time, and thus minimizes the difference in hot-pressing effect between the surface and center of the lithium battery cell pack. This reduces the likelihood of surface over-pressing and intermediate delamination, improving the quality and performance of the lithium battery cell pack. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the structure of the lithium battery cell pack hot-pressing assembly described in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the enclosure panel described in an embodiment of this utility model.

[0024] In the picture:

[0025] 100. Hot press plate; 200. Enclosure plate; 210. Side plate; 2001. Heat conduction hole; 2002. Connecting groove; 2003. Clearance opening;

[0026] 1. Lithium battery cell pack; 11. Electrode tabs. Detailed Implementation

[0027] To make the technical problems solved by this utility model, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0028] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0030] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationships shown in the accompanying drawings. They are used solely for ease of description and simplification of operation, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are merely used for distinction in description and have no special meaning.

[0031] like Figure 1 As shown, the lithium battery cell pack hot-pressing assembly of this embodiment includes a hot-pressing plate 100 and a surrounding plate 200. There are two hot-pressing plates 100, spaced apart along a first direction, which abut against opposite sides of the lithium battery cell pack 1 along the first direction to hot-press the lithium battery cell pack 1. The surrounding plate 200 is located between the two hot-pressing plates 100 and has an annular structure surrounding the outer periphery of the lithium battery cell pack 1.

[0032] In the prior art, the two hot press plates 100 are usually arranged vertically and horizontally. Therefore, in this embodiment, "first direction" generally refers to the vertical direction, that is, the Z direction shown in the figure.

[0033] In this embodiment, a surrounding plate 200 is set between two hot press plates 100. The surrounding plate 200 has a ring structure and surrounds the outer periphery of the lithium battery cell pack 1. When the main body of the hot press equipment is started and the hot press plates 100 are driven to hot press the lithium battery cell pack 1, the surrounding plate 200 can play a role in heat insulation and heat preservation for the lithium battery cell pack 1 during the hot pressing process. This reduces the heat applied to the lithium battery cell pack 1 by the hot press plates 100 and dissipates into the air, thereby reducing the heating time in the middle of the lithium battery cell pack 1 and reducing the hot pressing time. This reduces the difference in hot pressing effect between the surface and the middle of the lithium battery cell pack 1, reduces the probability of surface over-pressure and middle delamination of the lithium battery cell pack 1, and improves the quality and performance of the lithium battery cell pack 1.

[0034] Furthermore, the enclosure 200 has several heat-conducting holes 2001 facing the outer periphery of the lithium battery cell pack 1.

[0035] While the enclosure 200 provides thermal insulation for the lithium battery cell pack 1 during the hot pressing process, the heat from the external heat source can be introduced into the inner side of the enclosure 200 through the heat conduction holes 2001. This allows the lithium battery cell pack 1 to be heated from the outer periphery of the enclosure, thereby improving the temperature uniformity of various areas of the lithium battery cell pack 1.

[0036] In this embodiment, the heat-conducting hole 2001 is a round hole. In other embodiments, the heat-conducting hole 2001 can also be any shape such as a square hole or an elliptical hole.

[0037] Furthermore, the inner wall of the enclosure 200 is provided with several connecting grooves 2002, the opening of the connecting grooves 2002 is directly opposite the outer periphery of the lithium battery cell pack 1, and the heat conduction hole 2001 is connected to the connecting grooves 2002.

[0038] Taking hot air as a heat source as an example, if the enclosure 200 only has heat-conducting holes 2001, and the inner wall of the enclosure 200 is in contact with the outer periphery of the lithium battery cell pack 1, the hot air introduced through the heat-conducting holes 2001 can only contact a portion of the outer periphery of the lithium battery cell pack 1 directly opposite the heat-conducting holes 2001. The contact area between the outer periphery of the lithium battery cell pack 1 and the hot air is small, resulting in poor heating effect. In this embodiment, by providing several connecting grooves 2002 on the inner wall of the enclosure 200 and connecting the heat-conducting holes 2001 and the connecting grooves 2002, when the inner wall of the enclosure 200 is in contact with the lithium battery cell pack 1, the hot air introduced through the heat-conducting holes 2001 can flow along the connecting grooves 2002 and contact the lithium battery cell pack 1, increasing the contact area between the hot air and the outer periphery of the lithium battery cell pack 1, and further improving the heating efficiency of the lithium battery cell pack 1.

[0039] Furthermore, the heat-conducting holes 2001 on the enclosure 200 are evenly distributed, thereby improving the heat uniformity of the outer periphery of the lithium battery cell pack 1.

[0040] Furthermore, the enclosure 200 includes four side plates 210, which are connected in sequence to form an annular rectangular structure. The lithium battery cell pack 1 is located inside the annular rectangular structure. At least one side plate 210 is provided with heat-conducting holes 2001 and connecting grooves 2002. The heat-conducting holes 2001 on each side plate 210 are distributed in n rows by m columns. The inner wall of the enclosure 200 is provided with n connecting grooves 2002 spaced apart along the first direction. Each row of heat-conducting holes 2001 on each side plate 210 is connected by a corresponding connecting groove 2002; where n≥1 and m≥1.

[0041] In this embodiment, the surrounding plate 200 is suitable for a square lithium battery cell pack 1. Each side plate 210 has heat-conducting holes 2001 and connecting grooves 2002, which can improve the heat uniformity of the outer periphery of the lithium battery cell pack 1. Figure 2 As shown, the length of the connecting groove 2002 extends horizontally, and multiple heat-conducting holes 2001 are provided at the bottom of the connecting groove 2002. This structural design can reduce the number of heat-conducting holes 2001, reduce the production cost of the enclosure 200, and at the same time enable the enclosure 200 to have a good heat insulation effect on the lithium battery cell pack 1, and ensure that the heating effect of the hot air device on the outer periphery of the lithium battery cell pack 1 through the heat-conducting holes 2001 is not affected.

[0042] For example, such as Figure 2 As shown, each side plate 210 has three rows of heat-conducting holes 2001 facing the lithium battery cell pack 1 and three connecting grooves 2002. Each row of heat-conducting holes 2001 is connected by a horizontally extending connecting groove 2002. The hot air device can heat the lithium battery cell pack 1 through the heat-conducting holes 2001 and introduce heat into the connecting groove 2002 through the heat-conducting holes 2001 to heat the lithium battery cell pack 1.

[0043] Furthermore, each side plate 210 is provided with a heat-conducting hole 2001 and a connecting groove 2002. The connecting grooves 2002 on two connected side plates 210 at the same height are connected. Taking the heat-conducting hole 2001 closest to the hot press plate 100 located below the lithium battery cell pack 1 as an example, the heat-conducting holes 2001 in the first row of each side plate 210 are connected by a connecting groove 2002. The connecting groove 2002 passes through both ends of the side plate 210 and connects with the connecting groove 2002 on the other side plate 210, thereby enabling heating of the corner position of the lithium battery cell pack 1 without dead angles.

[0044] In other embodiments, multiple transversely spaced connecting grooves 2002 may be provided on the inner side of each side plate 210, the length of the connecting grooves 2002 extending along a first direction, and each row of heat-conducting holes 2001 being connected through a connecting groove 2002.

[0045] Furthermore, multiple connecting grooves 2002 extending laterally and multiple connecting grooves 2002 extending in the first direction can be simultaneously provided on the inner side of each side plate 210. Each row of heat-conducting holes 2001 is connected through a connecting groove 2002, and each column of heat-conducting holes 2001 is connected through a connecting groove 2002. Of course, in other specific embodiments, the connecting grooves 2002 can also be designed as inclined structures, which will not be elaborated further.

[0046] In other embodiments, heat-conducting holes 2001 and connecting grooves 2002 (not shown in the figure) may be simultaneously provided on only one of the side plates 210. Heat can be introduced into each connecting groove 2002 through the heat-conducting holes 2001 to contact the corresponding outer peripheral surface of the lithium battery cell pack 1. Alternatively, heat-conducting holes 2001 and connecting grooves 2002 (not shown in the figure) may be provided on both side plates 210 of the enclosure 200 facing the width direction of the lithium battery cell pack 1 to achieve heating of the outer periphery of the lithium battery cell pack 1.

[0047] Furthermore, in embodiments where heat-conducting holes 2001 and connecting grooves 2002 are provided on some side plates 210, connecting grooves 2002 (not shown in the figure) are provided on the inner side of the remaining side plates 210. The connecting grooves 2002 on the two connected side plates 210 are interconnected, so that heat can be introduced into the connecting grooves 2002 on the inner side of each side plate 210 through a smaller number of heat-conducting holes 2001, thereby heating the periphery of the lithium battery cell pack 1.

[0048] Furthermore, the inner wall of the enclosure 200 is attached to the outer periphery of the hot-pressed lithium battery cell pack 1. That is to say, before hot pressing, there is a gap between the inner wall of the enclosure 200 and the outer periphery of the lithium battery cell pack 1. During the hot pressing and shaping process of the lithium battery cell pack 1, the enclosure 200 can limit the shape of the outer periphery of the lithium battery cell pack 1, so that the outer periphery of the lithium battery cell pack 1 remains flat, thereby further improving the shaping effect of the lithium battery cell pack 1.

[0049] Furthermore, the dimension of the enclosure 200 along the first direction (the height of the enclosure 200) is equal to the dimension of the lithium battery cell pack 1 along the first direction after hot pressing (the thickness of the lithium battery cell pack 1). In other words, the height of the enclosure 200 is less than the height of the lithium battery cell pack 1 before hot pressing. In this embodiment, the enclosure 200 can limit the downward pressure of the hot pressing plate 100 located above, so as to prevent the lithium battery cell pack 1 from being over-pressurized.

[0050] Furthermore, the length of the enclosure 200 extends along the second direction (X direction in the figure), the width of the enclosure 200 extends along the third direction (Y direction in the figure), the distance between the two side plates 210 of the enclosure 200 opposite each other along the second direction is L1, the dimension of the lithium battery cell pack 1 before hot pressing along the second direction (width of the lithium battery cell pack 1) is L2, L1-L2=1~5mm; the distance between the two side plates 210 of the enclosure 200 opposite each other along the third direction is K1, the dimension of the lithium battery cell pack 1 before hot pressing along the third direction (length of the lithium battery cell pack 1) is K2, K1-K2=1~5mm, and the first direction, the second direction and the third direction are perpendicular to each other.

[0051] In other words, in this embodiment, the difference between the distance between the two side plates 210 in the width direction of the enclosure 200 and the width of the lithium battery cell pack 1 is controlled within the range of 1~5mm. Specifically, this difference is 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, etc. Similarly, in this embodiment, the difference between the distance between the two side plates 210 in the length direction of the enclosure 200 and the length of the lithium battery cell pack 1 is controlled within the range of 1~5mm. The thickness can be 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, etc. If either of the two differences is too small or both differences are too small, the side plate 210 will cause overpressure on the lithium battery cell pack 1 during the hot pressing process. If either of the two differences is too large or both differences are too large, it may cause the side plate 210 to fail to contact the corresponding outer surface of the lithium battery cell pack 1 during the hot pressing process, affecting the heating effect of the outer periphery of the lithium battery cell pack 1 and resulting in poor shaping effect.

[0052] Furthermore, the dimension of the enclosure 200 along the first direction (the height of the enclosure 200) is H1, and the dimension of the lithium battery cell pack 1 along the first direction before hot pressing (the thickness of the lithium battery cell pack 1) is H2. H1-H2=1~5mm, and this difference is the safe hot pressing range of the lithium battery cell pack 1 on the hot pressing plate 100. By controlling this distance within the range of 1~5mm, such as 1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.5mm, 4mm, 4.5mm, or 5mm, the degree of hot pressing of the lithium battery cell pack 1 can be controlled.

[0053] Furthermore, the enclosure 200 has a clearance opening 2003 for the tabs 11 of the lithium battery cell pack 1 to pass through, so as to avoid the tabs 11 being damaged due to the small distance between the outer periphery of the lithium battery cell pack 1 and the inner wall of the enclosure 200.

[0054] Specifically, before and after hot pressing, the tab 11 and the side wall of the clearance opening 2003 are always in clearance fit to avoid damaging the tab 11.

[0055] Furthermore, the clearance 2003 is located at the end of the enclosure 200 along the first direction.

[0056] When the clearance opening 2003 is located at the upper end of the enclosure 200, the enclosure 200 is first placed on the lower hot press plate 100, and then the tab 11 of the lithium battery cell pack 1 is aligned with the clearance opening 2003 and placed inside the enclosure 200; when the clearance opening 2003 is located at the lower end of the enclosure 200, the lithium battery cell pack 1 is first placed on the lower hot press plate 100, and then the clearance opening 2003 of the enclosure 200 is aligned with the tab 11 of the lithium battery cell pack 1 and placed on the lower hot press plate 100.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A lithium battery cell pack hot-pressing assembly, characterized in that, include: Two hot press plates are spaced apart along a first direction and can abut against two opposite sides of the lithium battery cell pack along the first direction to hot press the lithium battery cell pack. A surrounding panel is located between the two hot-pressing plates and is arranged in a ring around the outer periphery of the lithium battery cell pack.

2. The lithium battery cell pack hot-pressing assembly according to claim 1, characterized in that, The enclosure has several heat-conducting holes facing the outer periphery of the lithium battery cell.

3. The lithium battery cell pack hot-pressing assembly according to claim 2, characterized in that, The inner wall of the enclosure is provided with several connecting grooves, the openings of the connecting grooves are directly opposite the outer periphery of the lithium battery cell pack, and the heat conduction holes are connected to the connecting grooves.

4. The lithium battery cell pack hot-pressing assembly according to claim 3, characterized in that, The enclosure includes four side plates, which are connected in sequence to form a ring-shaped rectangular structure. At least one side plate is provided with heat-conducting holes and a connecting groove. The heat-conducting holes on each side plate are distributed in n rows and m columns. The inner wall of the side plate is provided with n connecting grooves spaced apart along the first direction. Each row of heat-conducting holes on each side plate is connected by a corresponding connecting groove; where n≥1 and m≥1.

5. The lithium battery cell pack hot-pressing assembly according to claim 4, characterized in that, Each of the side plates is provided with the heat-conducting hole and the connecting groove, and the connecting grooves at the same height on the inner walls of two connected side plates are connected.

6. The lithium battery cell pack hot-pressing assembly according to claim 4, characterized in that, The inner wall of the enclosure is bonded to the outer periphery of the hot-pressed lithium battery cell pack.

7. The lithium battery cell pack hot-pressing assembly according to claim 4, characterized in that, The dimension of the enclosure along the first direction is not greater than the dimension of the lithium battery cell pack along the first direction after hot pressing.

8. The lithium battery cell pack hot-pressing assembly according to claim 4, characterized in that, The length of the enclosure extends along a second direction, and the width of the enclosure extends along a third direction. The distance between two opposite side panels of the enclosure along the second direction is L1, and the dimension of the lithium battery cell pack before hot pressing along the second direction is L2, where L1-L2=1~5mm; the distance between two opposite side panels of the enclosure along the third direction is K1, and the dimension of the lithium battery cell pack before hot pressing along the third direction is K2, where K1-K2=1~5mm; the first direction, the second direction, and the third direction are perpendicular to each other; and / or, The dimension of the enclosure along the first direction is H1, and the dimension of the lithium battery cell pack along the first direction before hot pressing is H2, where H1-H2=1~5mm.

9. The lithium battery cell pack hot-pressing assembly according to any one of claims 1 to 8, characterized in that, The enclosure has a clearance opening for the tabs of the lithium battery cell pack to pass through.

10. The lithium battery cell pack hot-pressing assembly according to claim 9, characterized in that, The clearance opening is located at the end of the enclosure along the first direction.

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