Battery cell hot pressing device

Abstract

The utility model discloses a battery cell hot-pressing device which comprises two pressing plates, the two pressing plates are oppositely arranged in a spaced mode, a containing space used for containing a battery cell is formed between the two pressing plates, at least one of the two pressing plates is used for heating the battery cell, and each pressing plate is provided with a pressing face facing the other pressing plate; the driving mechanism is connected with at least one of the two pressing plates and used for driving the two pressing plates to be oppositely opened and closed; wherein two spaced pressing parts are convexly arranged on the pressing surface of at least one of the two pressing plates, one of the two pressing parts is used for pressing the part, exceeding the pole piece, of the diaphragm at one end of the battery cell, and the other one of the two pressing parts is used for pressing the part, exceeding the pole piece, of the diaphragm at the other end of the battery cell. The battery cell hot-pressing device performs hot-pressing on the battery cell, diaphragms at two ends of the battery cell prepared by hot-pressing are mutually bonded, even if the internal temperature of the battery cell is relatively high, the diaphragms are not easy to generate thermal shrinkage deformation to cause contact of positive and negative pole pieces, the probability of short circuit in the battery cell is reduced, and the safety performance of the battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium battery production, and particularly relates to a core hot pressing device. Background Art

[0002] A lithium battery refers to a battery containing lithium (including metallic lithium, lithium alloy, lithium ion, and lithium polymer) in an electrochemical system. In recent years, due to many advantages such as long cycle life, good safety performance, and fast charge and discharge, lithium batteries have been widely used in fields such as digital products.

[0003] Lithium batteries usually use winding or laminating equipment to assemble a positive electrode plate, a negative electrode plate, and a separator to form a battery core, and then encapsulate the battery core in a housing for preparation. Currently, the separator used in the battery core has a low melting point and general high-temperature resistance. When the temperature inside the battery core is relatively high, the separator may undergo thermal shrinkage deformation, causing the positive and negative electrode plates to come into contact, thereby leading to an internal short circuit of the battery core, gradually triggering thermal runaway, and having low safety performance. Summary of the Utility Model

[0004] The main objective of the utility model is to propose a core hot pressing device, aiming to solve the technical problem of the low safety performance of the current battery core.

[0005] To achieve the above objective, the utility model proposes a core hot pressing device, which includes:

[0006] Two pressing plates, which are arranged oppositely at intervals, and a containing space for containing the battery core is formed between the two pressing plates. At least one of the two pressing plates is used for heating the battery core, and each pressing plate has a pressing surface facing the other pressing plate;

[0007] A driving mechanism, which is connected to at least one of the two pressing plates and is used for driving the two pressing plates to open and close relatively;

[0008] Wherein, two spaced-apart pressing parts are protruded on the pressing surface of at least one of the two pressing plates. One of the two pressing parts is used for pressing the part of the separator exceeding the electrode plate at one end of the battery core, and the other of the two pressing parts is used for pressing the part of the separator exceeding the electrode plate at the other end of the battery core.

[0009] In some embodiments, the pressing plate is a rectangular plate.

[0010] In some embodiments, the pressing part includes a pressing convex block, the pressing convex block extends along the width direction of the pressing plate, and the length direction of the pressing convex block is the same as the width direction of the battery core.

[0011] In some embodiments, the width of the pressing convex block is 1 mm to 3 mm.

[0012] In some embodiments, the pressing bump is integrally formed with the pressing plate.

[0013] In some embodiments, the pressing bump is movably disposed on the pressing plate, and an elastic member is disposed on the pressing plate. The elastic member is used to apply an elastic force to the pressing bump so that the pressing bump elastically presses the portion of the diaphragm of the battery cell that extends beyond the electrode tab.

[0014] In some embodiments, the pressing bump is provided with two limiting portions, and the two limiting portions protrude from opposite side walls of the pressing bump respectively;

[0015] The pressing plate is provided with a mounting groove, and two stopping portions are provided at the notch of the mounting groove. The two stopping portions extend from two opposite groove side walls of the mounting groove respectively;

[0016] The pressing bump is movably inserted into the mounting groove, and at least a part of the pressing bump passes through between the two stopping portions to pass out of the mounting groove. And the two stopping portions stop the two limiting portions of the pressing bump to limit the movement of the pressing bump in the mounting groove.

[0017] In some embodiments, the elastic member includes a spring. One end of the spring abuts against the pressing plate, and the other end of the spring abuts against the pressing bump.

[0018] In some embodiments, one of the two pressing plates is movably disposed and the other is fixedly disposed;

[0019] The driving mechanism is connected to the movably disposed pressing plate, and the movably disposed pressing plate is provided with two pressing portions.

[0020] In some embodiments, the driving mechanism includes a driving cylinder, and the piston rod of the driving cylinder is connected to the pressing plate; or,

[0021] The driving mechanism includes a driving motor and a lead screw. The driving motor is located at one end of the lead screw and is connected to the screw rod of the lead screw, and the nut seat of the lead screw is connected to the pressing plate.

[0022] The cell hot pressing device of the present utility model is used to hot press a cell. During hot pressing, the cell is placed in the accommodating space between two pressing plates. The two pressing plates are driven by a driving mechanism to close and press the cell, and at least one of the two pressing plates heats the cell, so that the electrode sheets and the separator of the cell are closely attached. At the same time, the two pressing parts on the pressing plates correspondingly press the parts of the separator at both ends of the cell that exceed the electrode sheets, so that the separators at both ends of the cell are closely attached. In this way, the separators at both ends of the cell obtained by hot pressing are bonded to each other. Even if the temperature inside the cell is relatively high, the separator is not likely to undergo thermal shrinkage deformation to cause the positive and negative electrode sheets to contact, reducing the probability of internal short circuit of the cell and improving the safety performance of the cell. Brief Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the cell hot pressing device in an embodiment of the present utility model;

[0024] Figure 2 is Figure 1 a schematic structural diagram of the cell hot pressing device in the embodiment from another perspective;

[0025] Figure 3 It is a schematic structural diagram of the cell hot pressing device in another embodiment of the present utility model;

[0026] Description of the Reference Numerals in the Drawings:

[0027] Label Name Label Name 100 Pressing plate 111 Pressing bump 200 Driving mechanism T Elastic member 110 Pressing portion 120 Installation groove 10 Electric core 121 Stopping portion 11 Separator 112 Limiting portion 12 Pole piece

[0028] The realization, functional features and advantages of the object of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Detailed Embodiment

[0029] Next, the solutions in the embodiments of the present utility model will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

[0030] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0031] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element present at the same time. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intermediate element present at the same time.

[0032] In addition, in the present utility model, the descriptions involving "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0033] The present utility model provides a cell hot pressing device. Referring to Figure 1 , the cell hot pressing device includes:

[0034] Two pressing plates 100, the two pressing plates 100 are arranged opposite to each other at intervals, and a accommodating space for accommodating the cell 10 is formed therebetween. At least one of the two pressing plates 100 is used for heating the cell 10, and each pressing plate 100 has a pressing surface facing the other pressing plate;

[0035] A driving mechanism 200, the driving mechanism 200 is connected to at least one of the two pressing plates 100 and is used for driving the two pressing plates 100 to open and close relatively;

[0036] Wherein, two spaced-apart pressing portions 110 are convexly provided on the pressing surface of at least one of the two pressing plates 100. One of the two pressing portions 110 is used for pressing the part of the separator 11 exceeding the electrode tab 12 at one end of the cell 10, and the other of the two pressing portions 110 is used for pressing the part of the separator 11 exceeding the electrode tab 12 at the other end of the cell 10.

[0037] The cell hot pressing device according to the embodiment of the present utility model is used for hot pressing the cell 10. The cell 10 can be a wound cell, and the so-called wound cell is formed by winding a stack combination of a positive electrode tab, a separator and a negative electrode tab. Wherein, at both ends of the cell 10 (i.e., the upper end and the lower end of the cell along its height direction), there is usually a part of the separator 11 exceeding the electrode tab 12.

[0038] In the battery cell, the function of the two pressing plates 100 is to press the battery cell 10. The battery cell 10 is placed in the accommodating space between the two pressing plates 100, and the two pressing plates 100 press the battery cell 10 in the closed state. Moreover, at least one of the two pressing plates 100 is used to heat the battery cell 10. As an optimized design, it can be set that both of the two pressing plates 100 can be used to heat the battery cell 10. During the hot pressing process, the staff can control the two pressing plates 100 to heat the battery cell 10 simultaneously according to the actual hot pressing requirements, or control one of the two pressing plates 100 to heat the battery cell 10. To realize the heating function of the pressing plate 100, a heating rod can be arranged in the pressing plate 100. By energizing the heating rod to make it work and generate heat, the pressing plate 100 can receive the heat of the heating rod to heat the battery cell 10. Among them, the pressing plate 100 can be a metal plate capable of conducting heat.

[0039] The function of the driving mechanism 200 is to drive the two pressing plates 100 to open and close relative to each other. Under the drive of the driving mechanism 200, the distance between the two pressing plates 100 can be reduced or increased. The driving mechanism 200 can be connected to one of the two pressing plates 100, or can be connected to both of the two pressing plates 100. Among them, the structural composition of the driving mechanism 200 can be selected and set by those skilled in the art.

[0040] When hot pressing the battery cell 10 in this embodiment, the battery cell 10 is placed in the accommodating space between the two pressing plates 100. The driving mechanism 200 is used to drive the two pressing plates 100 to close to press the battery cell 10, and at least one of the two pressing plates 100 is used to heat the battery cell 10, so that the electrode plate 12 of the battery cell 10 is closely attached to the separator 11. At the same time, the two pressing parts 110 on the pressing plate 100 correspondingly press the parts of the separator 11 at both ends of the battery cell 10 that exceed the electrode plate 12, so that the separators 11 at both ends of the battery cell 10 are closely attached to each other. In this way, the separators 11 at both ends of the battery cell 10 obtained by hot pressing are bonded to each other. Even if the temperature inside the battery cell 10 is relatively high, the separator 11 is not likely to undergo thermal shrinkage deformation to cause the positive and negative electrode plates 12 to contact, reducing the probability of internal short circuit of the battery cell 10 and improving the safety performance of the battery cell 10.

[0041] In some embodiments, the pressing plate 100 is a rectangular plate. In this embodiment, the pressing plate 100 is set as a rectangular plate, and the overall shape of the pressing plate 100 is adapted to the shape of the battery cell 10, which can realize comprehensive and reliable pressing of the battery cell 10.

[0042] In some embodiments, refer to Figure 1 and Figure 2, the pressing part 110 includes a pressing bump 111. The pressing bump 111 extends along the width direction of the pressing plate 100, and the length direction of the pressing bump 111 is the same as the width direction of the battery cell 10. In this embodiment, the pressing part 110 is configured with the structure of the pressing bump 111. The pressing bump 111 can be set with reference to the shape and size of the part where the separator 11 of the battery cell 10 extends beyond the electrode tab 12. Optionally, the pressing bump 111 is set as a rectangular bump. The length of the pressing bump 111 is equal to or greater than the width of the battery cell 10, and the width of the pressing bump 111 is equal to or greater than the length of the part where the separator 11 of the battery cell 10 extends beyond the electrode tab 12. When the driving mechanism 200 drives the two pressing plates 100 to close and press the battery cell 10, the pressing bump 111 of the pressing part 110 correspondingly presses the part where the separator 11 of the battery cell 10 extends beyond the electrode tab 12, and under the high temperature formed by heating the pressing plate 100, the parts where the separator 11 extends beyond the electrode tab 12 are mutually bonded.

[0043] In some embodiments, referring to Figure 1 , the width k of the pressing bump 111 is 1 mm to 3 mm. In this embodiment, the width k of the pressing bump 111 can be set within the range of 1 mm to 3 mm. For example, the width k of the pressing bump 111 can be set to 1 mm, 2 mm, or 3 mm. Optionally, the width k of the pressing bump 111 can be set with reference to the length of the part where the separator 11 of the battery cell 10 extends beyond the electrode tab 12. For example, when the length of the part where the separator 11 of the battery cell 10 extends beyond the electrode tab 12 is less than or equal to 1 mm, the width k of the pressing bump 111 can be set to 1 mm; when the length of the part where the separator 11 of the battery cell 10 extends beyond the electrode tab 12 is greater than 1 mm and less than or equal to 2 mm, the width k of the pressing bump 111 can be set to 2 mm; when the length of the part where the separator 11 of the battery cell 10 extends beyond the electrode tab 12 is greater than 2 mm and less than or equal to 3 mm, the width k of the pressing bump 111 can be set to 3 mm.

[0044] In some embodiments, referring to Figure 1 and Figure 2 , the pressing bump 111 and the pressing plate 100 are integrally formed. In this embodiment, the pressing plate 100 and the pressing bump 111 thereon can be integrally formed by a mold. There are few components and no additional assembly operations are required. Moreover, the structure is firm and the position accuracy is high.

[0045] In some embodiments, referring to Figure 3, the pressing bump 111 is movably arranged on the pressing plate 100. An elastic member T is arranged on the pressing plate 100. The elastic member T is used to apply an elastic force to the pressing bump 111, so that the pressing bump 111 elastically presses the part of the diaphragm 11 of the battery cell 10 that exceeds the electrode tab 12. In this embodiment, the moving direction of the pressing bump 111 is the same as the opening and closing direction of the pressing plate 100. That is, the pressing bump 111 can perform telescopic movement on the pressing surface of the pressing plate 100. Moreover, the direction of the elastic force applied by the elastic member T to the pressing bump 111 is the same as the extending direction of the pressing bump 111. Specifically, when the driving mechanism 200 drives the two pressing plates 100 to close, the pressing bump 111 on the pressing plate 100 retracts due to contacting the part of the diaphragm 11 of the battery cell 10 that exceeds the electrode tab 12 on the pressing surface of the pressing plate 100. And the elastic force applied by the elastic member T to the pressing bump 111 enables the pressing bump 111 to elastically press the part of the diaphragm 11 of the battery cell 10 that exceeds the electrode tab 12, which can not only ensure the bonding effect of the diaphragm 11, but also prevent damage to the diaphragm 11 caused by hard contact with the diaphragm 11, and improve the pressing quality. Among them, the elastic member T can adopt a spring, an elastic sheet, etc.

[0046] In some embodiments, referring to Figure 3 , an installation groove 120 is arranged on the pressing plate 100. Two stop portions 121 are arranged at the notch of the installation groove 120. The two stop portions 121 respectively extend from the two opposite groove side walls of the installation groove 120;

[0047] The pressing bump 111 is provided with two limiting portions 112. The two limiting portions 112 respectively protrude from the opposite side walls of the pressing bump 111; the pressing bump 111 is movably inserted into the installation groove 120. At least part of the pressing bump 111 passes through between the two stop portions 121 to penetrate out of the installation groove 120. And the two stop portions 121 stop the two limiting portions 112 of the pressing bump 111 to realize the limitation of the movement of the pressing bump 111 in the installation groove 120.

[0048] In this embodiment, the pressing plate 100 mounts the pressing protrusions 111 through the installation grooves 120. And according to the two set pressing protrusions 111, two installation grooves 120 are correspondingly arranged on the pressing plate 100, and each installation groove 120 correspondingly mounts one pressing protrusion 111. The pressing protrusion 111 can move in the installation groove 120, so as to realize expansion and contraction on the pressing surface of the pressing plate 100. Wherein, the two stop portions 121 at the notch of the installation groove 120 can stop the two limit portions 112 of the pressing protrusion 111, so as to limit the extending distance of the pressing protrusion 111, and can also prevent the pressing protrusion 111 from detaching from the installation groove 120 along its extending direction. In addition, the opposite two side walls of the installation groove 120 are slidably matched with the two side walls of the pressing protrusion 111 respectively, and can realize the movement guiding of the pressing protrusion 111 during the movement of the pressing protrusion 111. Further, based on the installation groove 120, the elastic member T can be arranged in the installation groove 120 and clamped between the bottom wall of the installation groove 120 and the pressing protrusion 111, so as to apply an elastic force to the pressing protrusion 111.

[0049] In some embodiments, referring to Figure 3 , the elastic member T includes a spring. One end of the spring abuts against the pressing plate 100, and the other end of the spring abuts against the pressing protrusion 111. In this embodiment, the elastic member T adopts a spring, and the spring has high elasticity and can maintain a stable shape and performance under changing heavy loads and deformations, with a long service life. To realize the installation of the spring, optionally, a first installation post is arranged on the pressing plate 100, and a second installation post is arranged on the pressing protrusion 111. One end of the spring is sleeved on the first installation post and abuts against the pressing plate 100, and the other end of the spring is sleeved on the second installation post and abuts against the pressing protrusion 111, and then is stably installed between the pressing plate 100 and the pressing protrusion 111 and provides an elastic force action for the pressing protrusion 111. Wherein, each pressing protrusion 111 is respectively provided with a plurality of springs, and the plurality of springs are arranged at intervals in sequence along the length direction of the pressing protrusion 111, and the distance between any two adjacent springs is equal, so as to enable the pressing protrusion 111 to apply a balanced pressing force to the diaphragm 11 along the width direction of the battery cell 10, which helps to improve the bonding effect of the part of the diaphragm 11 exceeding the electrode tab 12.

[0050] In some embodiments, referring to Figures 1 to 3 , one of the two pressing plates 100 is movably arranged, and the other is fixedly arranged;

[0051] The driving mechanism 200 is connected to the movably arranged pressing plate 100, and the movably arranged pressing plate 100 is provided with two pressing portions 110.

[0052] In this embodiment, the driving mechanism 200 drives the movably arranged pressing plate 100 to move away from or towards the fixedly arranged pressing plate 100, thereby changing the distance between the two pressing plates 100 to realize the relative opening and closing of the two pressing plates 100. Moreover, during the pressing process when the movably arranged pressing plate 100 moves towards the fixedly arranged pressing plate 100, the two provided pressing parts 110 correspondingly press the parts of the separator 11 at both ends of the battery cell 10 that exceed the electrode tab 12. Optionally, the movably arranged pressing plate 100 and the fixedly arranged pressing plate 100 are oppositely arranged in the vertical direction. By placing the battery cell 10 on the fixedly arranged pressing plate 100, subsequent hot pressing operations can be carried out.

[0053] In some embodiments, as Figure 1 shown, the driving mechanism 200 includes a driving cylinder, and the piston rod of the driving cylinder is connected to the pressing plate 100. Optionally, a connecting seat is arranged on the other side of the pressing plate 100 facing away from its pressing surface, and the piston rod of the driving cylinder is connected to the connecting seat and thus connected to the pressing plate 100. The driving cylinder drives its piston rod to extend and retract to correspondingly drive the pressing plate 100 to move. Or,

[0054] the driving mechanism 200 includes a driving motor and a lead screw. The driving motor is located at one end of the lead screw and is connected to the screw rod of the lead screw. The nut seat of the lead screw is connected to the pressing plate 100. The driving motor drives the screw rod of the lead screw to rotate, so that the nut seat of the lead screw moves along the screw rod, thereby driving the pressing plate 100 to move. Based on the driving motor and the lead screw adopted by the driving mechanism 200, a guide rail can also be correspondingly configured. The guide rail is opposite to the lead screw in position and is respectively arranged on both sides of the pressing plate 100, and the length direction of the provided guide rail is the same as the opening and closing direction of the pressing plate 100. The slider on the guide rail is connected to the pressing plate 100. When the driving mechanism 200 drives the pressing plate 100 to move, the provided guide rail can guide the pressing plate 100 and improve the movement accuracy of the pressing plate 100.

[0055] In practical applications, the driving mechanism 200 can be set by choosing any one of the above structural compositions.

[0056] The above are only partial or preferred embodiments of the present utility model. Neither the text nor the drawings can limit the protection scope of the present utility model. All equivalent structural transformations made by using the content of the specification and drawings of the present utility model under the concept of a whole of the present utility model, or direct / indirect applications in other related technical fields are included in the protection scope of the present utility model.

Claims

1. A battery core hot pressing device, characterized in that: include: Two pressing plates, the two pressing plates are arranged opposite to each other with a space for accommodating the battery cell formed therebetween, at least one of the two pressing plates is used to heat the battery cell, and each pressing plate has a pressing surface facing the other pressing plate; A driving mechanism, the driving mechanism is connected to at least one of the two pressing plates and is used to drive the two pressing plates to open and close relative to each other; Among them, the pressing surface of at least one of the two pressing plates is convexly provided with two spaced-apart pressing parts, one of the two pressing parts is used to press the part of the diaphragm at one end of the battery cell that protrudes from the pole piece, and the other of the two pressing parts is used to press the part of the diaphragm at the other end of the battery cell that protrudes from the pole piece.

2. The battery core hot pressing device according to claim 1, characterized in that: The pressing plate is a rectangular plate.

3. The battery core hot pressing device according to claim 2, characterized in that: The pressing portion includes a pressing protrusion, and the pressing protrusion is extended along the width direction of the pressing plate. The length direction of the pressing protrusion is the same as the width direction of the battery core.

4. The battery core hot pressing device according to claim 3, characterized in that: The width of the pressing protrusion is 1 mm to 3 mm.

5. The battery core hot pressing device according to claim 3, characterized in that: The holding protrusion is integrally formed with the pressing plate.

6. The battery core hot pressing device according to claim 3, characterized in that: The pressing protrusion is movably arranged on the pressing plate, and an elastic member is arranged on the pressing plate. The elastic member is used to apply elastic force to the pressing protrusion so that the pressing protrusion can elastically press the part of the diaphragm of the battery cell that exceeds the pole piece.

7. The battery core hot pressing device according to claim 6, characterized in that: The pressing plate is provided with a mounting groove, and the groove opening of the mounting groove is provided with two stopper parts, and the two stopper parts extend from two opposite groove side walls of the mounting groove respectively; The pressing protrusion is provided with two limiting parts, and the two limiting parts are respectively protruded from the opposite side walls of the pressing protrusion; the pressing protrusion is movably inserted into the installation groove, and the pressing protrusion at least partially passes between the two stopping parts to pass through the installation groove, and the two stopping parts stop the two limiting parts of the pressing protrusion to limit the movement of the pressing protrusion in the installation groove.

8. The battery core hot pressing device according to claim 6 or 7, characterized in that: The elastic member comprises a spring, one end of the spring is pressed against the pressing plate, and the other end of the spring is pressed against the pressing protrusion.

9. The battery core hot pressing device according to any one of claims 1 to 7, characterized in that: One of the two pressing plates is movably arranged, and the other is fixedly arranged; The driving mechanism is connected to the movably arranged pressing plate, and the movably arranged pressing plate is provided with two holding parts.

10. The battery core hot pressing device according to any one of claims 1 to 7, characterized in that: The driving mechanism comprises a driving cylinder, a piston rod of which is connected to the pressing plate; or, The driving mechanism comprises a driving motor and a lead screw, wherein the driving motor is located at one end of the lead screw and is connected to the lead rod of the lead screw, and the nut seat of the lead screw is connected to the pressure plate.

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