Battery cell stack assembly method and battery cell stack assembly device used therefor

Abstract

The present invention relates to a battery cell stack assembling method and a battery cell stack assembling device used therein, the method including: a first step of preparing a battery cell stack by arranging a plurality of battery cells with their cup portions facing each other; a second step of placing the battery cell stack on a support jig; a third step of placing a pair of grippers on each end of the width direction of the battery cell stack; a fourth step of fixing the battery cell stack with the pair of grippers and separating it from the support jig; and a fifth step of pressing the battery cell stack with a pressing member. Since frictional force is eliminated during the process of aligning the central axes of the battery cell stack, the central axes of the battery cell stack can be aligned easily and accurately.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0151482, filed November 6, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a battery cell stack assembling method and a battery cell stack assembling apparatus used therein, and more particularly, to a battery cell stack assembling method and a battery cell stack assembling apparatus used therein, which aligns a battery cell stack so that the battery cell stack accurately aligns with an assembly position of a bus bar frame assembly when assembling the battery cell stack and a bus bar frame assembly to be accommodated in a battery module. [Background technology]

[0003] 2. Description of the Related Art As the demand for environmentally friendly energy increases due to the tightening of carbon emission regulations, the number of devices that use lithium secondary batteries as an energy source is increasing.

[0004] Among these, lithium secondary batteries are increasingly being assembled into battery modules and battery packs for use in fields requiring high-power and high-capacity energy sources, such as electric vehicles.

[0005] In relation to the manufacture of the battery module, FIG. 1 shows a perspective view of a typical pouch-type battery cell, and FIG. 2 shows a perspective view of a battery cell stack in which the pouch-type battery cells of FIG. 1 are stacked and a bus bar frame assembly coupled thereto.

[0006] 1 and 2, a pouch-type battery cell 10 can be used as a lithium secondary battery that constitutes a battery module. The pouch-type battery cell 10 is manufactured by using a laminate sheet including a metal layer and a resin layer as a battery case, accommodating an electrode assembly inside the battery case, and then heat-sealing the outer periphery of the battery case. Electrode leads 11 connected to the electrode assembly protrude outside the outer periphery of the battery case and function as electrode terminals.

[0007] As shown in Fig. 2, a plurality of pouch-type battery cells 10 are arranged so that the bottoms of the cup portions 12 are in close contact with each other to form a battery cell stack 100, and a bus bar frame assembly 120 is coupled to each end of the battery cell stack 100 where the electrode leads 11 protrude. However, for ease of explanation, Fig. 2 shows the bus bar frame assembly 120 coupled to only one side of the battery cell stack 100.

[0008] To join the bus bar frame assembly 120 and the battery cell stack 100, the support jig 200 presses the battery cell stack 100 along the stacking direction S, and aligns the center of the width direction W of the bus bar frame assembly 120 and the center of the width direction W of the battery cell stack 100 so that they coincide with each other.

[0009] The support jig 200 is formed with fixing pins for guiding the position of the bus bar frame assembly, and the bus bar frame assembly 120 has fixing holes 121, and the bus bar frame assembly 120 is placed on the support jig 200 so that the fixing pins pass through the fixing holes 121.

[0010] In this way, since the bus bar frame assembly 120 is placed at a fixed position on the support jig, the battery cell stack 100 must be aligned to match the joining position of the bus bar frame assembly 120. If the center of the width direction W of the bus bar frame assembly 120 does not coincide with the center of the width direction W of the battery cell stack 100, dimensional defects in the battery module may occur, which may also affect product quality.

[0011] FIG. 3 is a vertical cross-sectional view of a conventional misaligned battery cell stack.

[0012] Referring to FIG. 3 , the battery cell stack 100 is placed on the support jig 200, and is pressed from both sides toward the central axis C1 of the battery cell stack to reduce the volume of the battery cell stack 100 and align the central axis C1 of the battery cell stack with the center of the bus bar frame assembly 120.

[0013] Here, the weight of the battery cell stack 100 may generate a friction force F in the direction of the arrow between the upper surface of the support jig 200 and the lower surface of the battery cell stack 100. Due to this friction force F, the force pressing from the right side becomes smaller than the force pressing from the left side, and the position where the resultant force of the pressing forces from both sides becomes zero may shift to the right of the central axis C2 of the support jig.

[0014] In this way, if the bus bar frame assembly 120 is coupled to the fixing pin of the support jig 200 with the central axis C1 of the battery cell stack shifted to the right, the central axis C2 of the support jig and the central axis C1 of the battery cell stack will not coincide.

[0015] Therefore, prior to coupling the battery cell stack to the bus bar frame assembly, it is necessary to develop a technology for aligning the battery cell stack so that the central axis of the battery cell stack coincides with the central axis of the support jig and stably coupling them without being affected by friction. Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery cell stack assembling method and a battery cell stack assembling device used therein, which can align the central axis of a support jig on which the battery cell stack is placed so that it coincides with the central axis of the battery cell stack, and assemble the battery cell stack in a state in which the joining position of the bus bar frame assembly and the joining position of the battery cell stack are accurately aligned. [Means for solving the problem]

[0017] To achieve this objective, a battery cell stack assembling method according to the present invention includes a first step of preparing a battery cell stack by arranging a plurality of battery cells with their cup portions facing each other; a second step of placing the battery cell stack on a support jig; a third step of placing a pair of grippers on each end of the width direction of the battery cell stack; a fourth step of fixing the battery cell stack with the pair of grippers and separating it from the support jig; and a fifth step of pressing the battery cell stack with a pressing member.

[0018] The support jig has a central axis (C2) of the support jig marked thereon, and the central axis (C1) of the battery cell stack may be positioned to coincide with the central axis (C2) of the support jig.

[0019] In the fourth step, the pair of grippers may first press the battery cell stack toward the center of the battery cell stack.

[0020] The pair of grippers can move the battery cell stack upward in a state where the pair of grippers presses the battery cell stack primarily.

[0021] Alternatively, the position of the battery cell stack can be fixed with the pair of grippers in a primary pressing state, and the support jig can be moved downward.

[0022] The pressing members may include a first pressing member and a second pressing member positioned outside each of the pair of grippers, and the pressing forces of the first pressing member and the second pressing member may be the same.

[0023] The central axis (C1) of the battery cell stack pressed in the fifth step may coincide with the central axis (C2) of the support jig.

[0024] The method may further include a sixth step of placing the battery cell stack pressed in the fifth step on the support jig and connecting electrode leads of the plurality of battery cells to a bus bar frame.

[0025] The support jig may have fixing pins formed thereon to be inserted into fixing holes of the bus bar frame.

[0026] A buffer pad may be disposed between the plurality of battery cells or at least one of the ends of the battery cell stack.

[0027] The present invention provides a battery cell stack assembling device used in the battery cell stack assembling method, and the device may include a support jig for arranging a battery cell stack including a plurality of battery cells, a pair of grippers for fixing the battery cell stack, a lifting unit for separating the battery cell stack from the support jig, and a pressing member for pressing the battery cell stack.

[0028] The lifting unit is connected to the pair of grippers, thereby moving the battery cell stack fixed by the pair of grippers.

[0029] Alternatively, the lifting unit may be connected to the support jig, thereby allowing the support jig to be moved downward while the battery cell stack is gripped and fixed in position by the pair of grippers.

[0030] Furthermore, the present invention can also be provided in the form of various combinations of means for solving the above problems. [Effects of the Invention]

[0031] As described above, the method for assembling a battery cell stack according to the present invention is not affected by frictional force during the process of aligning the central axes of the battery cell stack, and therefore the central axes of the battery cell stack can be easily aligned.

[0032] Therefore, the bus bar frame assembly and the battery cell stack can be assembled with their joining positions accurately aligned.

[0033] As a result, the time required to align the battery cell stack can be reduced, the assembly process can be simplified, and the dimensional uniformity of the assembled battery modules can be improved. [Brief explanation of the drawings]

[0034] [Figure 1] FIG. 1 is a perspective view of a typical pouch-type battery cell. [Figure 2] 2 is a perspective view of a battery cell stack in which the pouch-type battery cells of FIG. 1 are stacked and a bus bar frame assembly coupled thereto. FIG. [Figure 3] 1 is a side cross-sectional view of a conventional misaligned battery cell stack. [Figure 4] 1A to 1C are diagrams sequentially illustrating a method for assembling a battery cell stack according to the present invention. [Figure 5] FIG. 2 is a perspective view of a support jig, a battery cell stack, and a bus bar frame assembly according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, with reference to the accompanying drawings, a detailed description will be given of an embodiment of the present invention that will enable a person skilled in the art to easily carry out the present invention. In describing the operation principle of the embodiment of the present invention in detail, detailed description of related well-known functions or configurations will be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0036] Throughout the drawings, the same reference numerals are used for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only a direct connection but also an indirect connection via another element therebetween. Furthermore, unless otherwise specified, "including a certain element" does not mean that other elements are excluded, but that other elements may also be included.

[0037] Descriptions that limit or specify additional elements are applicable to all inventions and are not limited to a particular invention unless otherwise limited.

[0038] Throughout the description and claims of this invention, the singular includes the plural unless otherwise stated.

[0039] Throughout the description and claims, "or" includes "and" unless otherwise stated. Thus, "comprising A or B" means the three cases of including A, including B, or including both A and B.

[0040] The invention will now be explained with reference to the drawings and in conjunction with detailed embodiments.

[0041] FIG. 4 shows a step-by-step method for assembling a battery cell stack according to the present invention.

[0042] Referring to FIG. 4 , the method for assembling a battery cell stack according to the present invention includes a first step (a) of preparing a battery cell stack 100 by arranging a plurality of battery cells 10 with their cup portions facing each other; a second step (b) of placing the battery cell stack 100 on a support jig 200; a third step (c) of placing a pair of grippers 300 on each end of the width direction W of the battery cell stack 100; a fourth step (d) of fixing the battery cell stack 100 with the pair of grippers 300 and separating it from the support jig 200; and a fifth step (e) of pressing the battery cell stack 100 with a pressing member 400.

[0043] The battery cell stack is formed by arranging the pouch-type battery cells shown in Fig. 1 in close contact with each other, and optionally, a buffer pad 130 may be disposed between the plurality of battery cells 10 or at least one of the ends of the battery cell stack 100. Fig. 4 shows a state in which one buffer pad 130 is disposed at each end of the battery cell stack 100, and three buffer pads 130 are disposed at regular intervals between the plurality of battery cells 10.

[0044] The provision of the buffer pad 130 can prevent damage to the pouch-type battery cells 10 when the battery cell stack 100 is pressed by the pressing member 400. In addition, the buffer pad 130 can accommodate the portion of the pouch-type battery cell 10 that expands in volume during charging and discharging, preventing the overall size of the battery cell stack 100 from increasing.

[0045] The central axis C2 of the support jig is marked on the upper surface of the support jig 200 on which the battery cell stack 100 is placed, so the central axis C1 of the battery cell stack 100 can be placed so as to coincide with the central axis C2 of the support jig.

[0046] In the third step, a pair of grippers 300 is disposed at each end of the width direction W of the battery cell stack, and the pair of grippers 300 can initially press the battery cell stack 100 toward the center of the battery cell stack.

[0047] The first pressing means pressing to an extent that the pair of grippers can grip the battery cell stack and move the battery cell stack, or pressing to an extent that the battery cell stack is gripped so as to prevent the battery cell stack from descending when a support jig that supports the battery cell stack at the bottom of the battery cell stack moves away from the battery cell stack and the state of supporting the battery cell stack is released.

[0048] In this way, the fourth step can be performed by moving the battery cell stack upward while the pair of grippers 300 is primarily pressing the battery cell stack 100.

[0049] Alternatively, the fourth step can be performed by fixing the position of the battery cell stack 100 with the pair of grippers 300 first pressing the battery cell stack 100 and then moving the support jig 200 downward.

[0050] Here, in order to move the support jig 200 downward, an elevator 500 for raising and lowering the support jig 200 may be disposed below the support jig 200 .

[0051] FIG. 4 shows a folding lifting unit 500 that lowers the support jig 200 when folded and raises the support jig when extended, but the lifting unit applicable to the present invention is not limited to this and also includes a type that uses a hydraulic cylinder or a servo motor, etc.

[0052] In the past, when a pressing member was used to press a battery cell stack, frictional force was generated at the contact surface between the bottom surface of the battery cell stack and the top surface of the support jig, which caused the central axis of the battery cell stack to not coincide with the central axis of the support jig.

[0053] Therefore, in order to prevent the above-mentioned problems, the present invention separates the battery cell stack 100 from the support jig 200 in the fourth step. Therefore, the process of pressing the battery cell stack 100 with the pressing member in the fifth step can be performed in an environment where no frictional force is generated between the battery cell stack and the support jig.

[0054] In detail, the pressing member 400 includes a first pressing member 410 and a second pressing member 420 located outside each of the pair of grippers 300, and the first pressing member 410 and the second pressing member 420 can press the battery cell stack with the same amount of pressing force toward the central axis C1 of the battery cell stack.

[0055] In the second step, the first pressing member 410 and the second pressing member 420 press the battery cell stack 100 with the same pressing force while the central axis C1 of the battery cell stack and the central axis C2 of the support jig are aligned. Here, since there is no influence of friction, the contraction distances at both ends of the battery cell stack 100 based on the central axis C1 of the battery cell stack are the same. As a result, after being pressed in the fifth step, the central axis C1 of the battery cell stack is aligned with the central axis C2 of the support jig.

[0056] FIG. 5 is a perspective view of a support jig, a battery cell stack, and a bus bar frame assembly according to the present invention.

[0057] Referring to FIG. 5, the battery cell stack 100 compressed in the fifth step is placed on a support jig 200 and positioned so that the central axis C1 of the battery cell stack coincides with the central axis C2 of the support jig.

[0058] The bus bar frame assembly 120 has fixing holes 121 formed therein for fixing the bus bar frame assembly 120 to the support jig 200, and the bus bar frame assembly 120 is placed on the support jig 200 so that the fixing pins 210 positioned perpendicular to the upper surface of the support jig 200 pass through the fixing holes 121.

[0059] Since the bus bar frame assembly 120 is disposed to face the electrode leads 11 of the battery cell stack 100, a sixth step of connecting the electrode leads 11 to the connecting portions of the bus bar frame assembly 120 may be further included.

[0060] A slit may be formed in the bus bar frame assembly 120 so that the electrode lead passes through, and a bus bar plate may be positioned adjacent to the slit. The end of the electrode lead may be bent through the slit, and the bent portion of the electrode lead may be welded to the bus bar plate.

[0061] A battery cell stack assembling device according to the present invention will be described with reference to Figures 4 and 5. The battery cell stack assembling device may include a support jig 200 for arranging a battery cell stack 100 including a plurality of battery cells 10, a pair of grippers 300 for fixing the battery cell stack 100, a lifting unit 500 for separating the battery cell stack 100 from the support jig 200, and a pressing member 400 for pressing the battery cell stack.

[0062] Unlike the example shown in FIG. 4, the lifting unit can be connected to a pair of grippers 300, so that the battery cell stack fixed by the pair of grippers can be moved away from the support jig.

[0063] Alternatively, as shown in FIG. 4 , the lifting unit 500 can be connected to the support jig 200, so that the battery cell stack 100 can be gripped and fixed in position by a pair of grippers 300, and the support jig 200 can be moved downward to separate the battery cell stack 100 and the support jig 200.

[0064] As described above, the present invention uses a method of pressing the battery cell stack while the battery cell stack is spaced apart from the support jig, thereby eliminating friction that may occur at the interface between the battery cell stack and the support jig when the battery cell stack is pressed. As a result, the battery cell stack and the support jig can be easily aligned, and the joining positions of the battery cell stack and the bus bar frame assembly can be accurately aligned.

[0065] Those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above content. [Explanation of symbols]

[0066] 10 Pouch-type battery cells 11 Electrode Lead 12 Cup section 100 battery cell stack 120 Busbar frame assembly 121 Fixing hole 130 buffer pad 200 Support Jig 210 Fixing pin 300 Gripper 400 Pressing member 410 First pressing member 420 Second pressing member 500 Lifting section C1 Central axis of battery cell stack C2 Central axis of support jig F Frictional force

Claims

1. a first step of preparing a battery cell stack by arranging a plurality of battery cells with their cup portions facing each other; a second step of placing the battery cell stack on a support jig; a third step of arranging a pair of grippers at each end of the battery cell stack in the width direction; a fourth step of fixing the battery cell stack with the pair of grippers and separating the battery cell stack from the support jig; a fifth step of pressing the battery cell stack with a pressing member; A method for assembling a battery cell stack, comprising:

2. The support jig has a central axis (C2) of the support jig indicated thereon, The battery cell stack assembling method according to claim 1 , wherein a central axis (C1) of the battery cell stack is positioned to coincide with a central axis (C2) of the support jig.

3. The method of assembling a battery cell stack according to claim 1 , wherein in the fourth step, the pair of grippers primarily press the battery cell stack toward the center of the battery cell stack.

4. The battery cell stack assembling method according to claim 3 , wherein the pair of grippers move the battery cell stack upward while applying a primary pressure.

5. The battery cell stack assembling method according to claim 3 , wherein the pair of grippers fix the position of the battery cell stack in a primary pressing state, and the support jig is moved downward.

6. the pressing member includes a first pressing member and a second pressing member located outside each of the pair of grippers, The battery cell stack assembling method according to claim 1 , wherein the pressing force of the first pressing member and the pressing force of the second pressing member are the same.

7. The battery cell stack assembling method according to claim 1 , wherein a central axis (C1) of the battery cell stack pressed in the fifth step coincides with a central axis (C2) of the support jig.

8. 2. The battery cell stack assembling method according to claim 1, further comprising a sixth step of placing the battery cell stack pressed in the fifth step on the support jig and connecting electrode leads of the plurality of battery cells to a bus bar frame.

9. The battery cell stack assembling method according to claim 8 , wherein the support jig is formed with fixing pins that are inserted into fixing holes in the bus bar frame.

10. The method of assembling a battery cell stack according to claim 1 , wherein a shock absorbing pad is disposed between the plurality of battery cells or at least one of the ends of the battery cell stack.

11. A battery cell stack assembling device used in the battery cell stack assembling method according to any one of claims 1 to 10, a support jig for arranging a battery cell stack including a plurality of battery cells; a pair of grippers for fixing the battery cell stack; a lifting unit for moving the battery cell stack away from the support jig; a pressing member that presses the battery cell stack; A battery cell stack assembling device comprising:

12. The battery cell stack assembling device according to claim 11 , wherein the lifting unit is connected to the pair of grippers to move the battery cell stack fixed by the pair of grippers.

13. The battery cell stack assembly device according to claim 11 , wherein the lifting unit is connected to the support jig, thereby moving the support jig downward while the battery cell stack is gripped and fixed in position by the pair of grippers.

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