Battery cell preparation method

Abstract

The invention relates to a battery cell preparation method which comprises the following steps: inserting m pole piece units into each layer of a Z-shaped laid diaphragm material belt, and respectively inserting m isolation gaskets into a plurality of layers of the diaphragm material belt to prepare m lamination stacks; moreover, each lamination stack comprises n lamination groups; the outer sides of the pole piece units at the two ends of each lamination group are separated from the diaphragm material belt by the isolation gaskets, so that the outer sides of the pole piece units at the bottom and the top are not compounded with the diaphragm material belt in the pressing process. After the diaphragm material belt is cut off, the m lamination stacks are separated from one another, the n lamination groups in each lamination stack are also separated from one another, and the pole piece units at the bottom and the top of each lamination group can be exposed after the isolation gaskets are taken out, so that m * n digital battery cells are obtained. Therefore, when the battery cell preparation method is adopted to prepare the digital battery cell, operations such as pole piece lamination are not needed, and a plurality of battery cells can be prepared at the same time, so that the production efficiency of the digital battery cell can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method for preparing a battery cell. Background Art

[0002] Lithium batteries have been widely used in electric vehicles, digital products and other fields. Their cells generally include pole pieces and diaphragms. Digital cells used in digital products are characterized by light weight and thin thickness, and the two sides of the outermost layer are exposed pole pieces. At present, the preparation method of digital cells is to first stack them according to the conventional stacking method and obtain a stack with diaphragms on both sides of the outermost layer, and then stick pole pieces on both sides of the stack after pressing. Compared with the preparation process of ordinary cells, the preparation process of digital cells is more complicated, resulting in lower production efficiency. Summary of the invention

[0003] Based on this, it is necessary to provide a battery preparation method that can improve the production efficiency of digital battery cells in response to the problem.

[0004] A method for preparing a battery cell comprises the following steps:

[0005] Step S10, inserting m pole piece units into each layer of the Z-shaped laid diaphragm material strip, and inserting m isolation pads into several layers thereof to obtain m lamination stacks, each of the lamination stacks comprising n laminated lamination groups, each of the lamination groups comprising a plurality of laminated pole piece units, and the outer sides of the pole piece units at both ends of each lamination group are separated from the diaphragm material strip by the isolation pads;

[0006] Step S20, cutting the diaphragm material strips between the m stacks of laminations and between the n stacks of laminations in each stack of laminations;

[0007] Step S30, taking out the isolation gasket to obtain m*n battery cells.

[0008] In one embodiment, the pole piece unit is a single pole piece, which includes a positive pole piece and a negative pole piece, and the polarities of two adjacent pole piece units in the same lamination group are opposite.

[0009] In one embodiment, each of the electrode units includes a positive electrode, a negative electrode, and a separator sheet sandwiched between the positive electrode and the negative electrode.

[0010] In one embodiment, the step S10 comprises the steps of:

[0011] The diaphragm material strip is firstly bent in a Z-shape into a curved structure having a plurality of V-shaped grooves, and the opening directions of two adjacent V-shaped grooves are opposite;

[0012] Then, the pole piece unit and the isolation gasket are respectively inserted into the corresponding V-shaped grooves.

[0013] In one embodiment, the step S10 comprises the steps of:

[0014] S11: placing the m pole piece units and the m isolation pads of the first layer at the starting end of the diaphragm material strip, and making the m isolation pads be located below the m pole piece units;

[0015] S12: driving the diaphragm strip to swing back and forth to achieve Z-shaped folding, and placing m pole piece units on the diaphragm strip each time folding, until m lamination groups are obtained;

[0016] S13: placing another m isolation pads on the m pole piece units on the top layer, and placing another m pole piece units on the m isolation pads;

[0017] Repeat steps S12 and S13 until m*n stacks of laminations are obtained.

[0018] In one embodiment, the step S20 includes the steps of: firstly pressing the m stacks of laminations as a whole; and then cutting the diaphragm material strips between the m stacks of laminations and between the n stacks of laminations in each stack of laminations.

[0019] In one embodiment, the step S20 comprises the steps of:

[0020] First, the diaphragm material strips between the m stacks of laminations are cut off to obtain m stacks of laminations separated from each other; then, the m stacks of laminations are pressed respectively; and then, the diaphragm material strips between the n stacks of laminations in each stack of laminations are cut off.

[0021] In one embodiment, the step S20 includes:

[0022] First, the diaphragm strips between the m stacks of laminations are cut to obtain m stacks of laminations separated from each other; then, the diaphragm strips between the n stacks of laminations in each stack of laminations are cut, and the top diaphragm and the bottom diaphragm of the stack of laminations are removed; and then, the m stacks of laminations are pressed separately.

[0023] In one of the embodiments, the step of cutting the diaphragm material strip between the n lamination groups in each lamination stack is: cutting along the stacking direction of the lamination group, and removing the side diaphragm covering the edge of each isolation gasket.

[0024] In one of the embodiments, m is equal to 2, and the two pole piece units located in the same layer are arranged at intervals along the width direction of the diaphragm material strip.

[0025] The above-mentioned battery cell preparation method can obtain m stacks of laminates during the lamination process by inserting m electrode units at a time, and each stack of laminates includes n stacks of laminates; since the outer sides of the electrode units at both ends of each stack of laminates are separated from the diaphragm strip by an isolation gasket, the outer sides of the electrode units at the bottom and top thereof are not compounded with the diaphragm strip during the pressing process. After the diaphragm strip is cut off, the m stacks of laminates are separated from each other, and the n stacks of laminates in each stack of laminates are also separated from each other. After the isolation gasket is removed, the electrode units at the bottom and top of each stack of laminates can be exposed, thereby obtaining m*n digital batteries. It can be seen that the preparation of digital batteries by the above-mentioned battery cell preparation method does not require operations such as electrode lamination, and multiple batteries can be prepared at the same time, so the production efficiency of digital batteries can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of a process for preparing a battery cell in one embodiment of the present invention;

[0028] Figure 2 for Figure 1 A schematic diagram of a scenario of a cell preparation method shown;

[0029] Figure 3 for Figure 2 A top view of one layer of the stack of laminations shown;

[0030] Figure 4 for Figure 1 A schematic flow chart of step S10 in the battery cell preparation method. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0037] See also Figure 1 and Figure 2 The present invention provides a method for preparing a battery cell, and the method for preparing a battery cell comprises steps S10 to S30. Among them:

[0038] Step S10, inserting m pole piece units 120 into each layer of the Z-shaped laid diaphragm strip 110, and inserting m isolation gaskets 200 into several layers thereof to obtain m lamination stacks 100, each lamination stack 100 includes n laminated lamination groups 100b stacked one on the other, each lamination group 100b includes a plurality of laminated pole piece units 120 stacked one on the other, and the outer sides of the pole piece units 120 at both ends of each lamination group 100b are separated from the diaphragm strip 110 by isolation gaskets 200.

[0039] Each fold of the diaphragm strip 110 is a layer. Since m pole piece units 120 are inserted into each layer of the diaphragm strip 110, m parallel stacks 100 can be obtained after the stacking is completed. Each stack 100 includes a plurality of pole piece units 120 stacked in sequence from bottom to top, and each layer of a single stack 100 includes only one pole piece unit 120. The m isolation pads 200 inserted into each layer correspond to the m pole piece units 120 of the same layer, respectively, and can separate the multiple pole piece units 120 in each stack 100 into n stack groups 100b. Wherein, m and n are both natural numbers greater than or equal to 2.

[0040] The pole piece unit 120 can be a single pole piece, such as a positive pole piece or a negative pole piece; in addition, the pole piece unit 120 can also be a composite pole piece unit, which generally includes a positive pole piece, a negative pole piece, and a diaphragm sheet material clamped between the positive pole piece and the negative pole piece. In one embodiment, the pole piece unit 120 is a single pole piece, and the polarities of two adjacent pole piece units 120 in the same stack 100b are opposite. In another embodiment, the structures of multiple pole piece units 120 are the same, and they are all the composite pole piece units mentioned above. In this way, there is no need to distinguish each pole piece unit 120 when performing the stacking operation, which is conducive to improving efficiency and preventing operational errors.

[0041] Each lamination group 100b includes a plurality of pole piece units 120, and adjacent pole piece units 120 are separated by a Z-shaped diaphragm strip 110. The plurality of pole piece units 120 in the lamination group 100b are stacked in sequence in the up-down direction, and the pole piece units 120 at the bottom and the top respectively refer to the first pole piece unit 120 and the last pole piece unit 120 from the bottom to the top. The outer side of the pole piece unit 120 refers to the side of the two pole piece units 120 facing away from each other. It can be seen that an isolation gasket 200 is arranged between the lower surface of the bottom pole piece unit 120 of each lamination group 100b and the diaphragm strip 110, and an isolation gasket 200 is also arranged between the upper surface of the top pole piece unit 120 and the diaphragm strip 110. The surface of the isolation gasket 200 is generally subjected to surface treatment such as coating, and is not easy to adhere to the diaphragm strip 110 and the pole piece unit 120.

[0042] In one embodiment, two adjacent lamination groups 100b share a common isolation pad 200. That is, the isolation pad 200 is disposed on the last pole piece unit 120 of one lamination group 100b in the same lamination stack 100, and the first pole piece unit 120 of the next lamination group 100b is disposed on the surface of the isolation pad 200. In this way, the number of isolation pads 200 used can be significantly reduced, thereby reducing costs and simplifying processes.

[0043] For details, please refer to Figure 4 In one embodiment, the above step S10 includes steps S11 to S13. Among them: step S11, placing the first layer of m pole piece units 120 and m isolation gaskets 200 at the starting end of the diaphragm strip 110, and making the m isolation gaskets 200 located below the m pole piece units 120. Step S12, driving the diaphragm strip 110 to swing back and forth to achieve Z-shaped folding, and placing m pole piece units 120 on the diaphragm strip 110 each time folding until the m stacks 100b are obtained; step S13, placing another m isolation gaskets 200 on the top layer of m pole piece units 120, and placing another m pole piece units 120 on the m isolation gaskets 200;

[0044] The above steps S12 and S13 are repeated until m*n lamination sets 100b are obtained.

[0045] Specifically, first, m isolation gaskets 200 and the first layer of m pole piece units 120 are sequentially placed at the starting end of the diaphragm material strip 110. Then, the diaphragm material strip 110 is swung once and folded, and then the second layer of m pole piece units 120 are placed on the folded diaphragm material strip 110, and respectively correspond to the first layer of m pole piece units 120. And so on, until the required number of pole piece units 120 are placed in the diaphragm material strip 110, and two adjacent pole piece units 120 are separated by the diaphragm material strip 110, thereby obtaining the first batch of m stacking sheets 100b.

[0046] Then, another m isolation gaskets 200 are placed on the last layer of m pole piece units 120 of the first batch of laminated sheets 100b, and the first layer of m pole piece units 120 of the next batch of laminated sheets 100b are placed on m isolation gaskets 200. In this way, the isolation gaskets 200 can separate two adjacent batches of laminated sheets 100b along the stacking direction. Next, the diaphragm strip 110 is swung once and folded, and then the second layer of m pole piece units 120 of the second batch of pole piece groups 100b are placed on the folded diaphragm strip 110, until the required number of pole piece units 120 are placed in the diaphragm strip 110, thereby obtaining the second batch of m lamination groups 100b. Repeat the above process until the nth batch of m*n lamination groups 100b is obtained.

[0047] In addition, in another embodiment, the above step S10 includes the following steps: firstly bending the diaphragm material strip 110 into a Z-shape into a curved structure having a plurality of V-shaped grooves, and the opening directions of two adjacent V-shaped grooves are opposite; and then respectively sending the pole piece unit 120 and the isolation gasket 200 into the corresponding V-shaped grooves.

[0048] The diaphragm strip 110 is bent and formed in one step, which is conducive to improving production efficiency. Specifically, multiple pole piece units 120 and isolation gaskets 200 can be obtained at the same time, and the obtained pole piece units 120 and isolation gaskets 200 are synchronously sent into the corresponding V-shaped grooves. Compared with the method of taking pieces one by one and stacking them, inserting multiple pole piece units 120 and isolation gaskets 200 into the corresponding multiple V-shaped grooves at the same time can greatly improve the stacking efficiency.

[0049] In addition, the membrane strip 110 can be bent into a curved structure with multiple V-shaped grooves in a variety of ways. For example, a suction plate (not shown) can be used to absorb the surfaces of the two opposite sides of the membrane strip 110 and move back to back to bend the membrane strip 110 into a curved structure with multiple V-shaped grooves. Moreover, by applying a force to the membrane strip 110 through the negative pressure, the wear of the membrane strip 110 can be reduced. Moreover, after the membrane strip 110 is Z-folded, the suction plate is located on the outside of the membrane strip 110, so it is convenient to withdraw the suction plate later.

[0050] For another example, support rollers may be used to respectively abut the surfaces of the two opposite sides of the diaphragm material strip 110 and move toward each other, so as to bend the diaphragm material strip 110 into a curved structure having a plurality of V-shaped grooves. That is, the support roller on the left side abuts the surface on the left side of the diaphragm material strip 110 and moves to the right, while the support roller on the right side can abut the surface on the right side of the diaphragm material strip 110 and move to the left, thereby cooperating to form a plurality of V-shaped grooves on the diaphragm material strip 110, and realizing the Z-shaped folding of the diaphragm material strip 110. After the electrode unit 120 is inserted, the support roller can be pulled out.

[0051] Step S20 , cutting the diaphragm strips 110 between the m laminate stacks 100 and between the n laminate groups 100 b in each laminate stack 100 .

[0052] Before or after the diaphragm strip 110 is cut, a pressing operation is generally required. The purpose of pressing is to compress and compound the layers in the laminate group 100b along the stacking direction, that is, the up and down direction shown in the figure, so as to obtain a compact battery cell 100a. Specifically, the laminate stack 100 can be pressed by hot pressing. During the hot pressing process, the laminate stack 100 needs to be heated, so that the composite effect between the layers in the laminate group 100b can be better, so as to improve the reliability of the obtained battery cell 100a.

[0053] Since the outer sides of the pole piece units 120 at both ends of each stack 100b are isolated from the diaphragm strip 110 by the isolation gasket 200, the outer sides of the pole piece units 120 at the bottom and top of each stack 100b cannot be combined with the diaphragm strip 110. After the pressing is completed, each stack 100b can form a battery cell 100a. By cutting the diaphragm strip 110, the m*n stacks 100b, i.e. the final battery cells 100a, can be separated from each other. Specifically, the stack 100b can be cut along the diaphragm strip 110. Figure 3 The diaphragm strip 110 is cut along the X cutting line to separate the m lamination stacks 100 , and the diaphragm strip 110 is cut along the Y cutting line to separate the n lamination groups 100 b in each lamination stack 100 .

[0054] Step S30, taking out the isolation spacer 200 to obtain m*n battery cells.

[0055] Since the outer sides of the electrode unit 120 at the bottom and top of each stack 100b cannot be compounded with the diaphragm material strip 110 and will not adhere to the isolation gasket 200, the electrode unit 120 at the bottom and top of each battery cell 100a will be exposed after the isolation gasket 200 is removed, and the resulting battery cell 100a is a digital battery cell. It can be seen that when the digital battery cell is prepared using the above-mentioned battery cell preparation method, it is not necessary to perform operations such as electrode lamination, which is similar to the preparation process of ordinary batteries, and multiple digital batteries can be prepared at the same time. Therefore, the average time required to prepare each battery cell 100a is significantly shortened, which helps to further improve production efficiency.

[0056] like Figure 3 As shown, specifically in one embodiment, m is equal to 2. That is, two pole piece units 120 are inserted into each layer of the Z-shaped diaphragm strip 110. The two pole piece units 120 located on the same layer are spaced apart along the width direction of the diaphragm strip 110. The two pole piece units 120 are oriented in opposite directions, and their pole ears are respectively oriented toward the two edges in the width direction of the diaphragm strip 110. Such an arrangement can effectively prevent the pole ears of the pole piece unit 120 from being blocked. Moreover, all the battery cells 100a finally obtained are consistent, and the two long sides of the pole piece unit 120 are not exposed to the outside, and the stability of the battery cell 100a is better.

[0057] Of course, in other embodiments, m may also be greater than 2, such as equal to 4, that is, four pole piece units 120 are inserted into the same layer, and the four pole piece units 120 may be distributed in a matrix.

[0058] As mentioned above, for the m stacks of laminated sheets 100 obtained by lamination, the diaphragm material strip 110 may be cut first and then pressed, or may be pressed first and then cut. Specifically in one embodiment, the above step S20 includes the steps of: first pressing the m stacks of laminated sheets 100 as a whole; and then cutting the diaphragm material strip 110 between the m stacks of laminated sheets 100 and between the n stacks of laminated sheets 100b in each stack of laminated sheets 100.

[0059] That is to say, after the lamination is completed, the m lamination stacks 100 are directly sent to the pressing station as a whole for simultaneous pressing, and after the pressing, the diaphragm strip 100 is cut to obtain a plurality of separated battery cells 100a. In this way, the entire production process is relatively simple, and the relative positions of the pole piece units 120 are not easily misaligned during pressing.

[0060] In another embodiment, the above step S20 includes: firstly cutting the diaphragm strips 110 between the m laminate stacks 100 to obtain m laminate stacks 100 separated from each other; then pressing the m laminate stacks 100 respectively; and then cutting the diaphragm strips 110 between the n laminate groups 100b in each laminate stack 100.

[0061] After obtaining m mutually separated stacks 100, the m stacks 100 can be respectively sent to m independent pressing stations, and after the pressing is completed, the m stacks 100 can be respectively sent to m independent cutting stations. In this way, the hot pressing device and cutting device in the prior art can be reused, and there is no need to design a hot pressing device and cutting device that can be compatible with the m stacks 100, which helps to save costs.

[0062] In addition, in another embodiment, the above-mentioned step S20 includes: first, cutting the diaphragm strip 110 between the m stacks of laminates 100 to obtain m separated stacks of laminates 100; then, cutting the diaphragm strip 110 between the n stack groups 100b in each stack of laminates 100, and cutting off the top diaphragm 111 and the bottom diaphragm 112 of the stack of laminates 100; and then, pressing the m stacks of laminates 100 respectively.

[0063] The top diaphragm 111 and the bottom diaphragm 112 refer to the top and bottom layers of the diaphragm strip 110 in each laminate stack 100, respectively. By cutting off the top diaphragm 111 and the bottom diaphragm 112, the isolation pads 200 at both ends can be exposed before pressing, so that the isolation pads 200 are in direct contact with the hot pressing plate of the hot pressing device during hot pressing. In this way, the diaphragm strip 110 can be prevented from sticking due to direct contact with the hot pressing plate during hot pressing, ensuring that the hot pressing plate is not damaged after long-term use.

[0064] Specifically, in one embodiment, the step of cutting the diaphragm strip 110 between n lamination groups 100 b in each lamination stack 100 is: cutting along the stacking direction of the lamination group 100 b and removing the side diaphragm 113 covering the edge of each isolation gasket 200 .

[0065] The side diaphragm 113 is the diaphragm strip 110 located at Figure 2 Specifically, the isolation gasket 200 may be provided with a long hollow groove, and when the isolation gasket 200 is inserted between the Z-shaped folded membrane strips 110, the hollow groove is located in the region A, and the hollow grooves of the plurality of isolation gaskets 200 are aligned. Therefore, the membrane strips 110 between the n stacked sheet groups 100b can be cut off and the side membrane 113 covering the edge of each isolation gasket 200 can be removed by cutting through the hollow groove.

[0066] After the side diaphragms 113 are cut off, there is no extra diaphragm on the side of each stack 100b, thereby preventing the extra diaphragm from sagging and affecting the performance of the final battery cell 100a. Of course, in other embodiments, the diaphragm strip 110 can also be cut along the side of the isolation gasket 200.

[0067] The above-mentioned battery cell preparation method can obtain m stacks of laminates 100 during the lamination process by inserting m pole piece units 120 at a time, and each stack of laminates 100 includes n stacks of laminates 100b; since the outer sides of the pole piece units 120 at both ends of each stack of laminates 100b are separated from the diaphragm material strip 110 by the isolation gasket 200, the outer sides of the pole piece units 120 at the bottom and top thereof are not compounded with the diaphragm material strip 110 during the pressing process. After the diaphragm material strip 110 is cut off, the m stacks of laminates 100 are separated from each other, and the n stacks of laminates 100b in each stack of laminates 100 are also separated from each other. After the isolation gasket 200 is removed, the pole piece units 120 at the bottom and top of each stack of laminates 100b can be exposed, thereby obtaining m*n digital batteries. It can be seen that the above-mentioned battery cell preparation method does not require operations such as electrode lamination when preparing digital batteries, and multiple batteries can be prepared at the same time, so the production efficiency of digital batteries can be significantly improved.

[0068] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a battery cell, characterized in that: Includes steps: Step S10, inserting m pole piece units into each layer of the Z-shaped laid diaphragm material strip, and inserting m isolation pads into several layers thereof to obtain m lamination stacks, each of the lamination stacks comprising n laminated lamination groups, each of the lamination groups comprising a plurality of laminated pole piece units, and the outer sides of the pole piece units at both ends of each lamination group are separated from the diaphragm material strip by the isolation pads; Step S20, cutting the diaphragm material strips between the m stacks of laminations and between the n stacks of laminations in each stack of laminations; Step S30, taking out the isolation gasket to obtain m*n battery cells.

2. The method for preparing a battery cell according to claim 1, characterized in that: The pole piece unit is a single pole piece, which includes a positive pole piece and a negative pole piece, and the polarities of two adjacent pole piece units in the same lamination group are opposite.

3. The method for preparing a battery cell according to claim 1, characterized in that: Each of the electrode sheet units comprises a positive electrode sheet, a negative electrode sheet and a diaphragm sheet material sandwiched between the positive electrode sheet and the negative electrode sheet.

4. The method for preparing a battery cell according to claim 1, characterized in that: The step S10 comprises the steps of: The diaphragm material strip is firstly bent in a Z-shape into a curved structure having a plurality of V-shaped grooves, and the opening directions of two adjacent V-shaped grooves are opposite; Then, the pole piece unit and the isolation gasket are respectively inserted into the corresponding V-shaped grooves.

5. The method for preparing a battery cell according to claim 1, characterized in that: The step S10 comprises the steps of: S11: placing the m pole piece units and the m isolation pads of the first layer at the starting end of the diaphragm material strip, and making the m isolation pads be located below the m pole piece units; S12: driving the diaphragm strip to swing back and forth to achieve Z-shaped folding, and placing m pole piece units on the diaphragm strip each time folding, until m lamination groups are obtained; S13: placing another m isolation pads on the m pole piece units on the top layer, and placing another m pole piece units on the m isolation pads; Repeat steps S12 and S13 until m*n stacks of laminations are obtained.

6. The method for preparing a battery cell according to claim 1, characterized in that: The step S20 includes the steps of: firstly pressing the m stacks of laminations as a whole; and then cutting the diaphragm material strips between the m stacks of laminations and between the n stacks of laminations in each stack of laminations.

7. The method for preparing a battery cell according to claim 1, characterized in that: The step S20 comprises the steps of: First, the diaphragm material strips between the m stacks of laminations are cut off to obtain m stacks of laminations separated from each other; then, the m stacks of laminations are pressed respectively; and then, the diaphragm material strips between the n stacks of laminations in each stack of laminations are cut off.

8. The method for preparing a battery cell according to claim 1, characterized in that: The step S20 comprises: First, the diaphragm strips between the m stacks of laminations are cut to obtain m stacks of laminations separated from each other; then, the diaphragm strips between the n stacks of laminations in each stack of laminations are cut, and the top diaphragm and the bottom diaphragm of the stack of laminations are removed; and then, the m stacks of laminations are pressed separately.

9. The method for preparing a battery cell according to any one of claims 6 to 8, characterized in that: The step of cutting the diaphragm material strip between the n lamination groups in each lamination stack is: cutting along the stacking direction of the lamination group, and removing the side diaphragm covering the edge of each isolation gasket.

10. The method for preparing a battery cell according to claim 1, characterized in that: m is equal to 2, and the two pole piece units located in the same layer are arranged at intervals along the width direction of the diaphragm material strip.

Images