Battery cell hot-pressing device and hot-pressing method

Abstract

The application provides an electric core hot pressing device and a hot pressing method. The electric core hot pressing device comprises oppositely arranged lower and upper hot pressing plates for hot pressing of electric cores, the opposite surfaces of the two plates are hot pressing surfaces, the upper hot pressing plate can move along the normal direction of the hot pressing surface, the device further comprises a flexible film which passes through the space between the lower and upper hot pressing plates and is elastically collapsed, and a supporting plate which can be displaced to the space between the flexible film and the lower hot pressing plate; when the supporting plate is located between the lower hot pressing plate and the flexible film, the flexible film is provided with a descending slope on both sides of the supporting plate to avoid a transfer mechanism of the electric core. The electric core hot pressing device can realize the overall feeding and discharging operation of the electric core by the cooperation of the flexible film which passes through the space between the lower and upper hot pressing plates and the supporting plate which is arranged between the flexible film and the lower hot pressing plate, so that the electric core is not subjected to uneven heating or hot pressing indentation and other adverse problems caused by the separated feeding and discharging operation.

Description

Technical Field

[0001] This invention relates to the field of battery hot pressing technology, and more specifically to a battery cell hot pressing device and hot pressing method. Background Technology

[0002] In the production process of lithium-ion batteries, whether stacked or wound, the cells need to undergo hot-pressing after winding. This process gives the cells a standardized shape, making it easier to fit into the casing during subsequent packaging and preventing scratches or damage. Furthermore, it ensures a tight bond between the cell film and the positive and negative electrode plates, guaranteeing the charging and discharging performance of the lithium battery.

[0003] Most existing hot pressing mechanisms adopt a split loading and unloading structure to facilitate the clamping of battery cells during the loading and unloading process, such as the technical solution disclosed in the invention patent entitled "A Battery Cell Hot Pressing Device" with publication number CN11073182A. This prior art discloses a scheme in which a lifting mechanism is set on the lower hot pressing plate to lift the battery cell, thereby separating the battery cell and facilitating its removal and unloading. Considering the relative movement between the lower hot pressing plate and the lifting mechanism, high requirements are placed on the processing and control of both. Even a slight discontinuity or gap between the two can leave indentations on the battery cell, and the film is very likely to cause a short circuit due to uneven local stress. At the same time, since the lifting mechanism occupies part of the space of the lower hot pressing plate, it will also cause uneven heating of the lower surface of the battery cell, affecting the hot pressing effect.

[0004] In summary, if a split-type hot-press loading and unloading mechanism is used, the processing requirements are very high and difficult to meet. It is also easy to cause indentations on the battery cells and lead to uneven heating of the cells, which is not allowed in battery production because it will cause the risk of battery short circuit. Summary of the Invention

[0005] To address the problems of existing hot pressing devices that easily create indentations on the battery cell, leading to uneven heating and affecting battery performance, and in severe cases, causing short circuits, this invention provides a battery cell hot pressing device and method.

[0006] The present invention provides a battery cell hot pressing device, comprising a lower hot pressing plate and an upper hot pressing plate arranged opposite to each other for hot pressing the battery cell, the opposing surfaces of the two being hot pressing surfaces, the upper hot pressing plate being movable along the normal direction of the hot pressing surface, characterized in that it further comprises a flexible membrane passing through and elastically tightened between the lower and upper hot pressing plates, capable of being displaced to a support plate between the flexible membrane and the lower hot pressing plate; when the support plate is located between the lower hot pressing plate and the flexible membrane, the flexible membrane forms a downward slope on both sides of the support plate to avoid the transfer mechanism of the battery cell.

[0007] Preferably, the flexible membrane is elastically connected to the tensioning end at both ends, and the tensioning end is disposed on the telescopic part. The telescopic part is able to generate displacement or displacement component in the normal direction of the hot pressing surface to change the height of the tensioning end relative to the hot pressing surface of the lower hot pressing plate.

[0008] Preferably, the tensioning end includes a clamping plate arranged along the width direction of the flexible membrane and a fixing plate arranged parallel to the clamping plate, which are elastically connected by a tension spring. The clamping plate tensions the flexible membrane in the width direction, and the fixing plate is fixed to the telescopic part.

[0009] Preferably, the tray is movable on a guide rail arranged along the extension direction of the flexible membrane.

[0010] Preferably, the pallet is capable of moving up and down along the normal direction of the hot-pressing surface.

[0011] The present invention also provides a hot pressing method for the above-mentioned hot pressing device for battery cells. In the process of loading or unloading battery cells, the hot pressing method controls the tray to enter between the flexible film and the lower hot pressing plate to lift the flexible film so that the flexible film forms a downward slope on both sides of the tray to avoid the transfer mechanism of the battery cells.

[0012] Preferably, in the hot pressing method, during the feeding or unloading of the battery cell, the telescopic part rises to lift the flexible membrane, and the pallet enters the space formed by the rising flexible membrane and the lower hot pressing plate. The telescopic part then descends to a height lower than the pallet, so that the flexible membrane contacts the pallet and forms a downward slope on both sides of the pallet to avoid the battery cell transfer mechanism.

[0013] Preferably, in the hot pressing method, during the feeding or unloading of the battery cell, the pallet moves horizontally between the flexible film and the lower hot pressing plate, the pallet rises to lift the flexible film so that the flexible film contacts the pallet and forms a downward slope on both sides of the pallet to avoid the battery cell transfer mechanism.

[0014] Preferably, in the feeding step, after the pallet rises and contacts the battery cell, it continues to rise slightly to separate the battery cell from the transfer mechanism; in the unloading step, after the pallet rises and the transfer mechanism is in place, the pallet lowers slightly to separate the battery cell from the flexible film.

[0015] The battery cell hot-pressing device of the present invention utilizes a flexible membrane passing through the lower and upper hot-pressing plates, coupled with a support plate positioned between the flexible membrane and the lower hot-pressing plate. This allows the flexible membrane to create a downward slope on both sides below the battery cell during loading and unloading. This slope creates space on both sides below the battery cell for the support arm to rest and move, thereby enabling the overall loading and unloading of the battery cell. This technical solution avoids the problems associated with a lifting mechanism on the lower hot-pressing plate, such as uneven heating of the battery cell or hot-pressing indentations. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the battery cell hot pressing device of the present invention;

[0017] Figure 2 This is a schematic diagram of the operation of the battery cell hot pressing device of the present invention;

[0018] Figure 3 This is a front view schematic diagram of the battery cell hot pressing device of the present invention;

[0019] Figure 4 This is a front view schematic diagram of the hot pressing state of the battery cell hot pressing device of the present invention.

[0020] In the picture,

[0021] W: Battery cell 1: Lower hot press plate 2: Upper hot press plate 3: Claw 4: Flexible film 5: Support plate 31: Support arm 41: Tensioning end 42: Telescopic part 51: Guide rail 411: Clamping plate 412: Fixing plate 413: Tensioning spring Detailed Implementation

[0022] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. In this specification, the dimensions of the drawings do not represent the actual dimensions. They are only used to illustrate the relative positional and connection relationships between the components. Components with the same name or the same reference numeral represent similar or identical structures and are limited to illustrative purposes.

[0023] To avoid the problems of uneven heating and indentation caused by separate hot pressing loading and unloading mechanisms, this invention provides an integrated hot pressing device for battery cells. Because the upper or lower hot pressing plate is a single unit, there is no need for a separate lifting mechanism. Therefore, it avoids some disadvantages of separate hot pressing loading and unloading, such as high processing precision requirements and the potential for short circuit failure of the battery cells. Figure 1 This is a schematic diagram of the battery cell hot pressing device of the present invention. It includes a lower hot pressing plate 1 and an upper hot pressing plate 2 arranged opposite each other, with their opposing surfaces being hot pressing surfaces. Heating devices are pre-embedded in the lower hot pressing plate 1 and the upper hot pressing plate 2 to heat the hot pressing surfaces of the lower hot pressing plate 1 and the upper hot pressing plate 2. The lower hot pressing plate 1 is fixedly arranged, and the upper hot pressing plate 2 is movable along the normal direction of the hot pressing surface. During the hot pressing operation, the battery cell W is located between the lower hot pressing plate 1 and the upper hot pressing plate 2. The upper hot pressing plate 2 moves closer to the lower hot pressing plate 1, pressing the battery cell W between the lower hot pressing plate 1 and the upper hot pressing plate 2 and holding it therein. During the hot pressing process, the battery cell W is heated by the hot pressing surface and simultaneously thinned under the pressure of the upper hot pressing plate 2, resulting in a tight bond between the layers and between the layers and the electrodes.

[0024] Before hot pressing, the cells of stacked or wound batteries are relatively loose and irregular in shape. Grippers cannot be used to hold the cells around their perimeter, as this not only fails to reliably hold them but may also puncture the cell film under excessive force, leading to a short circuit and ultimately causing more harm than good. Using suction cups to adsorb the cell's upper surface presents similar problems; during negative pressure adsorption of the cell film, only the outer film is subjected to force, making it difficult to grasp and transfer, and there is also the risk of puncturing the film due to foreign objects during adsorption. Therefore, the hot pressing device for the cells in this invention employs a lifting and unloading scheme, using grippers 3 to lift the cell W from its lower surface to complete the transfer of the cell W. Meanwhile, in order to facilitate the loading and unloading of battery cell W, the claw 3 includes two support arms 31 that extend parallel to the lower edge of battery cell W. The support arms 31 are placed on both sides of the lower surface of battery cell W to support battery cell W, and only contact battery cell W at the two opposite edges of the lower surface of battery cell W, thus exposing most of the lower surface of battery cell W, which facilitates the transfer of battery cell W during the loading and unloading process.

[0025] To facilitate the loading and unloading of battery cells W on the integral hot press plate, the battery cell hot press device also includes a flexible membrane 4 that passes through and elastically tightens between the lower hot press plate 1 and the upper hot press plate 2. The device also includes a support plate 5 that can be displaced between the flexible membrane 4 and the lower hot press plate 1. When the support plate 5 is positioned between the lower hot press plate 1 and the flexible membrane 4, it supports the flexible membrane 4 between the two support arms 31 of the support claw 3. The contact surface between the support plate 5 and the flexible membrane 4 is located between the two support arms 31 to avoid interference. Figure 2 As shown, during the loading or unloading process, when the pallet 5 enters between the flexible membrane 4 and the lower hot press plate 1, the pallet 5 lifts the flexible membrane 4. Thus, on each side of the pallet 5 where the two support arms 31 are located, the flexible membrane 4 forms an angled descent from the pallet 5. On both sides of the pallet 5, due to the descent of the flexible membrane 4, a small edge space is formed between the battery cell W and the flexible membrane 4. This space allows the support arms 31 to stop and move. Therefore, the support arms 31 can transport the battery cell W onto the flexible membrane 4 and then withdraw, thus loading the battery cell W. Similarly, during unloading, after lifting the battery cell W in the same manner, it can be unloaded by the support arms 31. Figure 4 As shown, under hot pressing conditions, the support plate 5 exits the position between the flexible film 4 and the lower hot pressing plate 1, descends, and presses the battery cell W along with the flexible film 4 onto the lower hot pressing plate 1. Further pressure is applied to hot press the battery cell W into shape. The flexible film 4 can generally be made of Teflon high-temperature cloth, which has good high-temperature resistance and can be used during the hot pressing process. It also has a relatively smooth surface, which can prevent foreign objects from puncturing the battery cell W. In fact, the hot pressing surface of the upper hot pressing plate 2 is generally also covered with a similar material to prevent the battery cell W from sticking together.

[0026] Figure 3This is a front view schematic diagram of the battery cell hot pressing device. The flexible membrane 4 is elastically connected to the tensioning end 41 at both ends, allowing the tensioning end 41 to extend and retract within a certain range to accommodate changes in the length of the flexible membrane 4 caused by the entry or exit of the support plate 5 during loading / unloading and hot pressing. The tensioning end 41 includes a clamping plate 411 arranged along the width direction of the flexible membrane 4 and a fixing plate 412 arranged parallel to the clamping plate 411, which are elastically connected by a tension spring 413. The tensioning end 41 is mounted on the telescopic part 42, specifically fixed to the movable end of the telescopic part 42 by the fixing plate 412. The telescopic part 42 can at least generate displacement or displacement component in the normal direction of the hot pressing surface to change the height of the tensioning end 41 relative to the hot pressing surface of the lower hot pressing plate 1. To achieve the required loading / unloading state, the telescopic part 42 first rises, raising the flexible membrane 4 as a whole, leaving space for the support plate 5 to enter between the lower hot pressing plate 1 and the flexible membrane 4. The support plate 5 moves into the position between the lower hot pressing plate 1 and the flexible membrane 4, and then the telescopic part 42 descends to form the aforementioned required descent angle. Similarly, when the tray 5 needs to be moved out, the flexible membrane 4 rises first, and after the flexible membrane 4 separates from the tray 5, the telescopic part 42 descends. The tray 5 is preferably moved along the extension direction of the flexible membrane 4 to reduce the space occupied by the system. Specifically, the tray 5 is moved on the guide rail 51 which is set along the extension direction of the flexible membrane 4.

[0027] The pallet 5 can also have a degree of freedom along the normal direction of the hot-pressing surface, meaning it can be configured to be height-adjustable. When it moves into the space between the flexible film 4 and the lower hot-pressing plate 1, it first rises to a certain height, lifting the flexible film 4 and creating the previously mentioned downward angle for the support arm 31 to load or unload materials. Optionally, the pallet 5 can also rise slightly further after it has already risen to a certain height. In the case of a loading process, when the pallet 5 rises for the first time, the support arm 31 transfers the battery cell W onto the flexible film 4. The pallet 5 then rises slightly again to disengage the battery cell W from the support arm 31, facilitating its removal from the support arm 31 and avoiding the potential damage to the battery cell W that could occur if the support arm 31 comes into contact with it during removal.

[0028] During the unloading process after hot pressing, as the flexible film 4 rises and the support plate 5 enters, the rise of the flexible film 4 will cause the battery cell W on it to detach from the base of the lower hot pressing plate 1, thereby avoiding the battery cell W from sticking to the lower hot pressing plate 1 after hot pressing and the corresponding damage caused by sticking.

[0029] Based on the above-mentioned battery cell hot pressing device, the present invention provides the following hot pressing method. During the battery cell loading and unloading process, the support plate 5 is positioned between the flexible film 4 and the lower hot pressing plate 1, and lifts the flexible film 4 so that the flexible film 4 forms a downward slope on both sides of the support plate 5 to provide space for the support arm 31 to move during loading or unloading.

[0030] With the tensioning ends 41 at both ends of the flexible membrane 4 being able to rise and fall, this step can be further refined as follows: the tensioning ends 41 rise, the support plate 5 moves between the flexible membrane 4 and the lower hot plate 1, and then the tensioning ends 41 fall. The tensioning ends 41 rise first to create space for the support plate 5, and the flexible membrane 4 falls again to create the slope required to avoid the support arm 31 on both sides of the support plate 5.

[0031] Correspondingly, the pallet 5 can also be height-adjustable. When the pallet 5 enters between the flexible film 4 and the lower hot press plate 1, it can rise to lift the flexible film 4, creating a slope on both sides of the flexible film 4. Furthermore, it can be slightly raised again when the feeding contact with the battery cell, so that the battery cell W is no longer in contact with the support arm 31. Similarly, when the unloading support arm 31 is in place, the pallet 5 can be slightly lowered to disengage the flexible film 4 from the battery cell W. The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A battery cell hot pressing device, comprising a lower hot pressing plate (1) and an upper hot pressing plate (2) disposed opposite to each other for hot pressing, wherein the opposing surfaces of the two are hot pressing surfaces, and the upper hot pressing plate (2) is movable along the normal direction of the hot pressing surface, characterized in that, It also includes a flexible membrane (4) that passes through and is elastically stretched between the lower hot platen (1) and the upper hot platen (2), and a support plate (5) that can be displaced between the flexible membrane (4) and the lower hot platen (1); During the loading or unloading process, the pallet (5) moves horizontally between the flexible membrane (4) and the lower hot platen (1). The pallet (5) rises to lift the flexible membrane (4) so ​​that the flexible membrane (4) contacts the pallet (5) and forms a downward slope on both sides of the pallet (5) to avoid the transfer mechanism of the battery cell (W).

2. The cell hot pressing device as described in claim 1, characterized in that, The flexible membrane (4) is elastically connected to the tension end (41) at both ends. The tension end (41) is provided on the telescopic part (42). The telescopic part (42) can at least generate displacement or displacement component in the normal direction of the hot pressing surface to change the height of the tension end (41) relative to the hot pressing surface of the lower hot pressing plate (1).

3. The cell hot pressing device as described in claim 2, characterized in that, The tensioning end (41) includes a clamping plate (411) arranged along the width direction of the flexible membrane (4) and a fixing plate (412) arranged parallel to the clamping plate (411). The two are elastically connected by a tension spring (413). The clamping plate (411) pulls the flexible membrane (4) in the width direction, and the fixing plate (412) is fixed on the telescopic part (42).

4. The cell hot pressing device as described in claim 1, characterized in that, The tray (5) is movable on a guide rail (51) arranged along the extension direction of the flexible membrane (4).

5. The cell hot pressing device as described in any one of claims 1 or 4, characterized in that, The pallet (5) can move up and down along the normal direction of the hot-pressing surface.

6. A hot pressing method based on the battery cell hot pressing device according to claim 1, characterized in that, During the loading or unloading of the battery cell (W), the hot pressing method controls the pallet (5) to enter between the flexible film (4) and the lower hot pressing plate (1) to lift the flexible film (4) so ​​that the flexible film (4) forms a downward slope on both sides of the pallet (5) to avoid the battery cell transfer mechanism.

7. A hot pressing method based on the battery cell hot pressing device according to claim 2, characterized in that, In the hot pressing method, during the feeding or unloading of the battery cell (W), the telescopic part (42) rises to lift the flexible membrane (4), and the pallet (5) enters the space formed by the rising flexible membrane (4) and the lower hot pressing plate (1). The telescopic part (42) then descends to a height lower than the pallet (5), so that the flexible membrane (4) contacts the pallet (5) and forms a downward slope on both sides of the pallet (5) to avoid the transfer mechanism of the battery cell (W).

8. The hot pressing method as described in claim 7, characterized in that, In the feeding step, after the pallet (5) rises, it contacts the battery cell (W) and continues to rise slightly to separate the battery cell (W) from the transfer mechanism; in the unloading step, after the pallet (5) rises and the transfer mechanism is in place, the pallet (5) lowers slightly to separate the battery cell (W) from the flexible film (4).

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