Hot pressing device of winding type battery cell and square lithium battery

Abstract

The hot-pressing device comprises a lower hot-pressing plate which is a plane tool, an upper hot-pressing plate, a lower hot-pressing plate, an upper hot-pressing plate and a lower hot-pressing plate, the upper hot-pressing plate is arranged right above the lower hot-pressing plate, and the lower surface of the upper hot-pressing plate is provided with a concave angle; and when the upper hot-pressing plate is close to the lower hot-pressing plate for hot-pressing shaping of the battery cell, the indentation angle of the upper hot-pressing plate enables the compaction density of the two side areas and the middle area of the battery cell between the upper hot-pressing plate and the lower hot-pressing plate to be consistent. According to the utility model, due to the design of the concave angle on the lower surface of the upper hot-pressing plate, the compaction of the areas on two sides and the middle area of the roll core is consistent in the hot-pressing shaping process, the stress of an internal pole piece is uniform, and the occurrence of wrinkled lithium precipitation in the battery core is reduced; meanwhile, the two sides and the middle area of the roll core bear different pressure sequences, and the distances between the upper and lower hot pressboards on the two sides and the middle area are different, so that the thickness of the roll core is more uniform.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium batteries, in particular to a hot pressing device for a winding type battery core and a square lithium battery. Background Art

[0002] As a common lithium-ion battery packaging form, square lithium batteries have the advantages of high packaging reliability, simple structure, and high energy density. They are widely used in electric vehicles, mobile devices, energy storage systems and other fields.

[0003] The current square aluminum shell lithium battery hot pressing process uses two parallel hot pressing plates to hot press and shape the wound battery cells. During hot pressing, the two sides of the wound battery cell are not parallel to the middle area (the thickness of the middle area of ​​the wound battery cell is greater than the thickness of the two side areas), resulting in uneven force on the two sides and the middle area during the hot pressing process, which in turn causes wrinkles inside the battery cell and then lithium precipitation; or, under the same compression conditions, the two side areas are more likely to rebound or be under-compressed because they are the winding areas, resulting in the thickness of the two side areas being greater than the thickness of the middle area, uneven thickness, and possibly excessive thickness. Utility Model Content

[0004] In view of the technical problems that the existing core hot pressing process leads to wrinkles, lithium deposition and uneven thickness of the battery cell, the purpose of the utility model is to provide a hot pressing device for a wound battery cell and a square lithium battery. By designing the concave angle of the lower surface of the upper hot pressing plate, the compression of the two side areas and the middle area of ​​the core are consistent during the hot pressing and shaping process, thereby producing a core with uniform thickness and obtaining a square lithium battery with excellent electrical performance.

[0005] According to one aspect of the present application, a hot pressing device for a wound battery cell is provided, comprising:

[0006] The lower hot pressing plate is a flat tooling;

[0007] An upper hot pressing plate, arranged directly above the lower hot pressing plate, wherein the lower surface of the upper hot pressing plate has a concave angle;

[0008] When the upper hot pressing plate is close to the lower hot pressing plate for hot pressing and shaping the battery cell, the concave angle of the upper hot pressing plate makes the compression of the two side areas and the middle area of ​​the battery cell therebetween consistent.

[0009] In some technical solutions, the upper hot pressing plate includes a first upper hot pressing plate and a second upper hot pressing plate stacked up and down, the lower surface of the second upper hot pressing plate has the concave angle, and the concave angle is consistent with the actual angle of the two side areas of the battery cell.

[0010] In some technical solutions, the first upper hot pressing plate is connected to the second upper hot pressing plate via a magnetic attraction member, and different types of battery cells can be adapted by replacing the second upper hot pressing plate with different concave angles.

[0011] In some technical solutions, the first upper hot pressing platen and the second upper hot pressing platen are connected via an adjusting member, and the concave angle of the second upper hot pressing platen can be adjusted by adjusting the connection length of the adjusting member.

[0012] In some technical solutions, the adjusting member is selected from a spring and / or a support foot.

[0013] In some technical solutions, the plurality of adjusting members are evenly arranged along the circumference of the second upper hot pressing plate.

[0014] In some technical solutions, the concave angle is formed by the middle area of ​​the second upper hot pressing plate being concave inward; or,

[0015] The concave angle is formed by the two side areas of the second upper hot pressing plate bending outward, while the middle area of ​​the second upper hot pressing plate is still a planar structure.

[0016] In some technical solutions, the hot pressing device further includes a hot pressing bottom plate, which is installed between the upper hot pressing plate and the lower hot pressing plate and is used to transfer heat to the battery cell and provide support; and / or,

[0017] The hot pressing device also includes a driving member, which is used to drive the upper hot pressing plate to move closer to and farther from the lower hot pressing plate to achieve hot pressing and shaping processing of the battery core.

[0018] In some technical solutions, the length of the upper hot pressing plate and the lower hot pressing plate is 8 to 25 cm, the width is 10 to 25 cm, the spacing is 12 to 40 cm, and the concave depth of the upper hot pressing plate is 0 to 5 cm.

[0019] According to another aspect of the present application, a square lithium battery is further provided, comprising a housing and a wound battery cell.

[0020] The wound battery cell is hot pressed and shaped using the hot pressing device as described above.

[0021] The utility model adopts the above technical solution to have at least the following beneficial effects:

[0022] 1. The utility model provides a hot pressing device for a wound cell and a square lithium battery. The concave angle of the lower surface of the upper hot pressing plate is designed so that during the hot pressing shaping process, the compression density of the two side areas and the middle area of ​​the core is consistent, and the internal pole piece is evenly stressed, which reduces the occurrence of wrinkles and lithium deposition inside the cell. At the same time, the pressure sequence of the two side areas and the middle area of ​​the core is different, and the distance between the upper and lower hot pressing plates of the two side areas and the middle area is also different, so that the thickness of the core is more uniform.

[0023] 2. The utility model provides a hot pressing device for a wound battery cell and a square lithium battery, which comprises a first upper hot pressing plate and a second upper hot pressing plate stacked up and down, and the concave angle of the lower surface of the second upper hot pressing plate is designed to be consistent with the actual angle of the two side areas of the battery cell, thereby controlling the compression of the two side areas and the middle area of ​​the winding core to be consistent; due to the split upper hot pressing plate design, the second upper hot pressing plate with different concave angles can be pre-customized to adapt to different types of battery cell winding cores, which saves the device cost and is convenient to operate;

[0024] 3. The utility model provides a hot pressing device for a wound battery cell and a square lithium battery. An adjusting piece is installed between a first upper hot pressing plate and a second upper hot pressing plate. The concave angle of the second upper hot pressing plate is adjusted by adjusting the connection length of the adjusting piece, thereby further reducing the equipment investment cost. The utility model is convenient to operate and has a reliable structure. The concave angle can be locally adjusted to perfectly match the actual angles of the two side areas of the battery cell, thereby improving the thickness uniformity of the battery cell hot pressing process and avoiding the occurrence of wrinkles and lithium deposition inside the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings and their marks required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 It is a schematic structural diagram of a hot pressing device for a wound-type battery cell according to an embodiment of the utility model.

[0027] The meanings of the symbols in the figure are as follows:

[0028] 11—first upper hot pressing plate, 12—second upper hot pressing plate, 20—winding core, 30—lower hot pressing plate. DETAILED DESCRIPTION

[0029] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the specific implementation methods of the utility model will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.

[0030] In order to simplify the drawings, only the parts related to the utility model are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".

[0031] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0032] In this article, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0033] Example 1

[0034] This embodiment provides a hot pressing device for a wound battery cell, such as Figure 1 , including an upper hot pressing plate and a lower hot pressing plate 30 arranged correspondingly from top to bottom, the lower hot pressing plate 30 is a flat tooling, the upper hot pressing plate is arranged directly above the lower hot pressing plate 30, the upper hot pressing plate includes a first upper hot pressing plate 11 and a second upper hot pressing plate 12 stacked up and down, the lower surface of the second upper hot pressing plate 12 has an inward concave angle, the core 20 is placed between the upper hot pressing plate and the lower hot pressing plate 30, the inward concave angle is consistent with the actual angle of the two side areas of the core 20, thereby controlling the compression consistency of the two side areas and the middle area of ​​the core 20.

[0035] In the above embodiment, the first upper hot pressing plate 11 and the second upper hot pressing plate 12 are of split design, and different types of battery cell cores can be adapted by pre-customizing the second upper hot pressing plate 12 with different concave angles, which is convenient for disassembly and assembly, saves equipment investment costs, and enriches product types.

[0036] In the above embodiment, the concave angle is formed by the middle area of ​​the second upper hot pressing plate 12 being concave inward; or, the concave angle is formed by the two side areas of the second upper hot pressing plate 12 being bent outward, while the middle area of ​​the second upper hot pressing plate 12 is still a planar structure; wherein the planar part is used to press the middle area of ​​the winding core 20, and the two side curved surfaces are used to press the two side areas of the winding core 20.

[0037] Preferably, the hot pressing device further comprises a hot pressing bottom plate, which is installed between the upper hot pressing plate and the lower hot pressing plate 30 for transferring heat to the battery cell and providing support.

[0038] Preferably, the hot pressing device further includes a driving member, which is used to drive the upper hot pressing plate to move closer to and away from the lower hot pressing plate 30 to achieve hot pressing and shaping of the battery cell.

[0039] In a specific example, the upper hot pressing plate and the lower hot pressing plate 30 are both square, the length of the upper hot pressing plate and the lower hot pressing plate 30 is 8 to 25 cm, the width is 10 to 25 cm, the spacing is 12 to 40 cm, and the inner concave depth of the upper hot pressing plate is 0 to 5 cm.

[0040] In this embodiment, the concave angle of the lower surface of the upper hot pressing plate is designed so that during the hot pressing and shaping process, the compression of the two side areas and the middle area of ​​the core 20 is consistent, and the internal pole pieces are evenly stressed, thereby reducing the occurrence of wrinkles and lithium deposition inside the battery cell. At the same time, the pressure sequences of the two side areas and the middle area of ​​the core 20 are different, and the distances between the upper and lower hot pressing plates on the two side areas and the middle area are also different, so that the thickness of the core 20 is more uniform.

[0041] Example 2

[0042] Based on the solution of Example 1, this embodiment further provides a fixed connection method between the first upper hot pressing plate 11 and the second upper hot pressing plate 12. Specifically, the connection can be achieved through a magnetic attraction mechanism between the two. The magnetic attraction mechanism includes a first magnetic attraction component arranged on the first upper hot pressing plate 11 and a second magnetic attraction component arranged on the second upper hot pressing plate 12. The number of the first magnetic attraction component and the second magnetic attraction component can be one or more, and the installation positions are preferably evenly distributed on the respective plate surfaces.

[0043] This embodiment adopts a magnetic connection method, which can be easily disassembled and assembled, and is beneficial to controlling production costs.

[0044] Example 3

[0045] Based on the scheme of Example 1, this embodiment further provides a movable connection method between the first upper hot pressing plate 11 and the second upper hot pressing plate 12. The first upper hot pressing plate 11 and the second upper hot pressing plate 12 are connected by an adjusting member. The concave angle of the second upper hot pressing plate 12 can be adjusted by adjusting the connection length of the adjusting member, which is convenient to operate.

[0046] Specifically, the adjusting member can select one or two of the spring and the support foot. Of course, other adjusting members with similar functions can also be used as replacements, as long as they meet the same or similar implementation effects as in this case.

[0047] In some preferred embodiments, the number of adjusting parts can be one or more, and the multiple adjusting parts are preferably evenly distributed on the circumference of the second upper hot pressing plate 12, so as to realize multi-position local adjustment of the concave angle, so as to perfectly adapt to the actual angles of the two side areas of the battery cell, improve the thickness uniformity of the battery cell hot pressing process, and avoid the occurrence of wrinkles and lithium deposition inside the battery cell.

[0048] Example 4

[0049] This embodiment provides the operating steps of the hot pressing device of the above embodiments 1-3:

[0050] The core 20 is placed flat on the lower hot pressing plate 30. The core 20 is divided into a middle area and two side areas. The two side areas are R-angled and have a thickness smaller than that of the middle area of ​​the core, which is consistent with the concave middle area of ​​the second upper hot pressing plate.

[0051] The upper hot pressing plate is driven to perform hot pressing. The lower surface of the second upper hot pressing plate 12 is provided with an inwardly concave curved surface. The inwardly concave curved surface can be customized to obtain the second upper hot pressing plate 12 with different angles. The second upper hot pressing plate 12 with different angles can be replaced to optimize the process according to the hot pressing requirements of the winding core 20. The angle composition of the inwardly concave curved surface of the second upper hot pressing plate 12 can also be adjusted by adjusting the connection length of the spring or the support foot.

[0052] During hot pressing, the two sides of the second upper hot pressing plate 12 first contact the two side areas of the core 20, and the middle of the second upper hot pressing plate 12 then contacts the middle area of ​​the core 20, thereby obtaining a core 20 with uniform thickness and no lithium deposition inside.

[0053] In the above embodiment, the hot pressing parameters mainly control the hot pressing temperature (45-120° C.), hot pressing time (0-500 s), and hot pressing pressure (0-15000 kgf).

[0054] Example 5

[0055] The present embodiment provides a square lithium battery, comprising a shell and a wound battery cell, wherein the wound battery cell is hot-pressed and shaped using the hot-pressing device and hot-pressing steps of embodiments 1-4.

[0056] The wound battery cell can achieve uniform thickness distribution across the length and width of the entire cell, thereby ensuring the performance consistency and safety of the battery.

[0057] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model shall be based on the attached claims.

[0058] Those skilled in the art should understand that although the present invention is described in the form of multiple embodiments, not every embodiment contains only one independent technical solution. Such description in the specification is only for the sake of clarity. Those skilled in the art should understand the specification as a whole and regard the technical solutions involved in each embodiment as being able to be combined into different embodiments to understand the scope of protection of the present invention.

Claims

1. A hot pressing device for a wound battery cell, characterized in that: include: The lower hot pressing plate is a flat tooling; An upper hot pressing plate, arranged directly above the lower hot pressing plate, wherein the lower surface of the upper hot pressing plate has a concave angle; When the upper hot pressing plate is close to the lower hot pressing plate for hot pressing and shaping the battery cell, the concave angle of the upper hot pressing plate makes the compression of the two side areas and the middle area of ​​the battery cell therebetween consistent.

2. The hot pressing device according to claim 1, characterized in that: The upper hot pressing plate includes a first upper hot pressing plate and a second upper hot pressing plate stacked up and down, the lower surface of the second upper hot pressing plate has the concave angle, and the concave angle is consistent with the actual angle of the two side areas of the battery cell.

3. The hot pressing device according to claim 2, characterized in that: The first upper hot pressing plate is connected to the second upper hot pressing plate via a magnetic attraction member, and different types of battery cells can be adapted by replacing the second upper hot pressing plate with different concave angles.

4. The hot pressing device according to claim 2, characterized in that: The first upper hot pressing plate is connected to the second upper hot pressing plate via an adjusting member, and the concave angle of the second upper hot pressing plate can be adjusted by adjusting the connection length of the adjusting member.

5. The hot pressing device according to claim 4, characterized in that: The adjusting member is selected from a spring and / or a support foot.

6. The hot pressing device according to claim 4 or 5, characterized in that: The plurality of adjusting members are evenly arranged along the circumference of the second upper hot pressing plate.

7. The hot pressing device according to claim 2, characterized in that: The concave angle is formed by the middle area of ​​the second upper hot pressing plate being concave inward; or, The concave angle is formed by the two side areas of the second upper hot pressing plate bending outward, while the middle area of ​​the second upper hot pressing plate is still a planar structure.

8. The hot pressing device according to claim 1, characterized in that: The hot pressing device further comprises a hot pressing bottom plate, which is installed between the upper hot pressing plate and the lower hot pressing plate and is used to transfer heat to the battery core and provide support; and / or, The hot pressing device also includes a driving member, which is used to drive the upper hot pressing plate to move closer to and farther from the lower hot pressing plate to achieve hot pressing and shaping processing of the battery core.

9. The hot pressing device according to claim 1, characterized in that: The length of the upper hot pressing plate and the lower hot pressing plate is 8 to 25 cm, the width is 10 to 25 cm, the spacing is 12 to 40 cm, and the inner concave depth of the upper hot pressing plate is 0 to 5 cm.

10. A square lithium battery, characterized in that: Including a shell and a wound battery cell, The wound battery cell is hot-pressed and shaped using a hot-pressing device as described in any one of claims 1 to 9.

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