Pole module manufactured using pole module preparation process

Abstract

The present application provides a pole piece module manufactured by a pole piece module preparation process, which is in the form of a roll core, and the roll core includes a positive electrode strip, a separator and a negative electrode strip stacked in sequence. The positive electrode strip includes a plurality of positive electrode connecting sheets, and the negative electrode strip includes a plurality of negative electrode connecting sheets, and each positive electrode connecting sheet is arranged corresponding to a corresponding negative electrode connecting sheet. The roll core is wound and folded in sequence at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the plurality of positive electrode connecting sheets. By making each positive electrode connecting sheet correspond to the corresponding negative electrode connecting sheet, the roll core can achieve an insulating effect without the need for a multi-layer separator, effectively avoiding the occurrence of internal short circuits caused by contact between the positive electrode strip and the negative electrode strip, while saving the use of separators, effectively improving the energy density of the roll core and reducing the production cost of the roll core.

Description

Technical Field

[0001] The present invention relates to the field of battery manufacturing, and in particular to a pole piece module manufactured using a pole piece module manufacturing process. Background Art

[0002] With the development of current science and technology, the consumer demand for portable electronic devices is becoming increasingly new. The requirements for their battery life are increasing, and the demand for customized power solutions to increase energy density is increasing. For flat large cylindrical special-shaped batteries (such as large-diameter button batteries R2032, etc.), due to their thin thickness, if the winding structure pole pieces are narrow and long, it is impossible to achieve slitting and winding, and the tape is easy to break. Therefore, traditional companies cannot use the radial winding method with the center of the circle as the axis for production. The industry mostly uses a stacking process for production. It is necessary to make multiple pole pieces into bags according to the designed number of layers, repeatedly place and stack the positive and negative poles, and weld the multi-layer lead-out empty foils from the multi-layer pole pieces to form bare cells. Its production process is not only cumbersome, but also requires the installation of multiple layers of diaphragms to insulate the positive and negative pole pieces, resulting in high production costs and low energy density of the battery due to the large thickness of the diaphragm, resulting in poor product quality consistency. Summary of the Invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a pole piece module with a simple structure, low production cost and not easy to break, and a pole piece module manufactured using a pole piece module preparation process with simplified procedures.

[0004] The object of the present invention is achieved through the following technical solutions:

[0005] A pole piece module manufactured using a pole piece module manufacturing process, in the form of a roll core, the roll core comprising a positive pole strip, a separator, and a negative pole strip stacked in sequence;

[0006] The positive electrode strip includes multiple positive electrode connecting sheets connected in sequence, and the negative electrode strip includes multiple negative electrode connecting sheets connected in sequence, and each positive electrode connecting sheet is arranged corresponding to the corresponding negative electrode connecting sheet; the winding core is wound and folded in sequence at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the multiple positive electrode connecting sheets.

[0007] In one embodiment, each of the positive electrode connecting sheets includes a first arcuate side, a first straight side, a second arcuate side, and a second straight side connected end to end in sequence, and the first straight side of one of two adjacent positive electrode connecting sheets is connected to the second straight side of the other to form a positive electrode boundary line between the two adjacent positive electrode connecting sheets;

[0008] Each of the negative electrode connecting sheets includes a third arcuate side, a third straight side, a fourth arcuate side, and a fourth straight side connected end to end in sequence, and the third straight side of one of two adjacent negative electrode connecting sheets is connected to the fourth straight side of the other to form a negative electrode boundary line between the two adjacent negative electrode connecting sheets;

[0009] In one embodiment, the maximum distance between the first arcuate edge and the second arcuate edge is defined as d, and the maximum distance between the third arcuate edge and the fourth arcuate edge is defined as D; the maximum distance d of the plurality of positive electrode connecting sheets increases successively along the arrangement direction, and the maximum distance D of the plurality of negative electrode connecting sheets increases successively along the arrangement direction.

[0010] In one embodiment, the first arc-shaped edge and the second arc-shaped edge are both circular arc-shaped edges;

[0011] The third arc-shaped edge and the fourth arc-shaped edge are both circular arc-shaped edges.

[0012] In one embodiment, the number of the positive electrode connecting sheets and the number of the negative electrode connecting sheets are both N, the N positive electrode connecting sheets are arranged in a one-to-one correspondence with the N negative electrode connecting sheets, the N positive electrode connecting sheets form N-1 positive electrode boundary lines, the N negative electrode connecting sheets form N-1 negative electrode boundary lines, and each positive electrode boundary line is arranged in a one-to-one correspondence with the corresponding negative electrode boundary line; N is an integer greater than 1.

[0013] In one embodiment, the positive electrode boundary lines formed by every two adjacent positive electrode connecting sheets are parallel to each other, and the negative electrode boundary lines formed by every two adjacent negative electrode connecting sheets are parallel to each other; and / or,

[0014] The positive electrode boundary line is parallel to the negative electrode boundary line.

[0015] A process for preparing a pole piece module, including the pole piece module of any of the above embodiments, comprises the following steps:

[0016] Processing the positive electrode strip and the negative electrode strip respectively through a die-cutting process;

[0017] Laminating the negative electrode tape and the separator and pressing and fixing them;

[0018] Arranging the positive electrode strip on the side of the separator away from the negative electrode strip to form a pole piece assembly to be wound;

[0019] The electrode assembly to be wound is sequentially wound and folded at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the plurality of positive electrode connecting sheets to obtain a winding core.

[0020] In one embodiment, after the negative electrode tape and the separator are stacked and pressed together, the positive electrode tape is placed on the side of the separator facing away from the negative electrode tape to form the electrode assembly to be wound, and the following steps are also included:

[0021] The negative electrode strip and the separator are heat-cut and sealed.

[0022] In one embodiment, after the electrode sheet assembly to be wound is wound and folded in sequence at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the plurality of positive electrode connecting sheets to obtain a winding core, the following steps are further included:

[0023] The winding core is pressed.

[0024] In one embodiment, the diaphragm is one of a PMMA-coated diaphragm, a PVDF-coated diaphragm and a PE-coated diaphragm.

[0025] Compared with the prior art, the present invention has at least the following advantages:

[0026] 1. The core formed by the electrode module of the present invention is sequentially wound and folded along the arrangement direction of the multiple positive electrode connecting tabs at the junction of each two adjacent positive electrode connecting tabs, resulting in a highly consistent core structure and improved product quality. Furthermore, by aligning each positive electrode connecting tab with the corresponding negative electrode connecting tab, the core can be insulated without the need for multiple layers of separators, effectively preventing internal short circuits caused by contact between the positive and negative electrode strips. This also reduces the amount of separator used, effectively increasing the energy density of the core and reducing its production cost.

[0027] 2. The pole piece module preparation process of the present invention adopts the method of first die-cutting the pole piece module to obtain a plurality of positive electrode connecting sheets and a plurality of negative electrode connecting sheets, and then performing a hot pressing composite operation on the negative electrode strip and the diaphragm to obtain the pole piece module to be wound, thereby improving the stability of the pole piece module, so that the situation of the winding strip being easily broken and the negative electrode strip being offset during winding will not occur, effectively improving the winding speed, and thus effectively improving the production efficiency of the core. The pole piece module is wound and folded, which can greatly simplify the process and avoid the situation where the pole piece is difficult to cut due to its thin thickness. Furthermore, the junction of each two adjacent positive electrode connecting sheets of the pole piece module to be wound is wound and folded in sequence along the arrangement direction of the multiple positive electrode connecting sheets, so that the structure of the core formed is more consistent, and there is no need to perform secondary sorting and alignment on the core, which not only effectively saves production time, but also greatly simplifies the process, thereby effectively improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is the side view of the structure of the pole piece module before explosion;

[0030] Figure 2 This is a schematic diagram of the structure of the pole piece module after explosion;

[0031] Figure 3 This is a top view of the structure of the pole piece module before explosion;

[0032] Figure 4 This is the process flow chart of the electrode module preparation process. DETAILED DESCRIPTION

[0033] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0034] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0036] The present application provides a pole piece module in the form of a roll core, which includes a positive electrode strip, a separator, and a negative electrode strip stacked in sequence. The positive electrode strip includes multiple positive electrode connectors, and the negative electrode strip includes multiple negative electrode connectors, with each positive electrode connector corresponding to a corresponding negative electrode connector. The roll core is sequentially wound and folded along the arrangement direction of the multiple positive electrode connectors at the junction of each two adjacent positive electrode connectors.

[0037] See also Figure 1 and Figure 2 As shown, in order to better understand the pole piece module 10 of the present invention, the pole piece module 10 of the present invention is further explained below.

[0038] In one embodiment, the electrode module 10, manufactured using the electrode module preparation process, is in the form of a roll core, which includes a positive electrode strip 100, a separator 200, and a negative electrode strip 300, which are sequentially stacked. The positive electrode strip 100 includes a plurality of sequentially connected positive electrode tabs 110, and the negative electrode strip 300 includes a plurality of sequentially connected negative electrode tabs 310, with each positive electrode tab 110 corresponding to a corresponding negative electrode tab 310. The roll core is sequentially wound and folded along the arrangement direction of the plurality of positive electrode tabs 110 at the junction of each two adjacent positive electrode tabs 110.

[0039] In this embodiment, the core formed by the electrode module 10 is sequentially wound and folded along the arrangement direction of the multiple positive electrode connecting sheets 110 at the junction of each two adjacent positive electrode connecting sheets 110, resulting in a more consistent core structure and improved product quality consistency. Furthermore, in traditional battery cell preparation processes, a multi-layer separator 200 is provided to prevent contact between positive and negative electrode sheets and internal short circuits. By aligning each positive electrode connecting sheet 110 with a corresponding negative electrode connecting sheet 310, the core can be insulated without a multi-layer separator 200, effectively preventing internal short circuits caused by contact between positive and negative electrode strips. This also saves the use of separator 200, effectively improving the energy density of the core and reducing the production cost of the core.

[0040] like Figure 2 As shown, in one embodiment, each positive electrode connecting sheet 110 includes a first arcuate edge 1110, a first straight edge 1120, a second arcuate edge 1130, and a second straight edge 1140 connected end to end in sequence. The first straight edge 1120 of one of two adjacent positive electrode connecting sheets 110 is connected to the second straight edge 1140 of the other to form a positive electrode boundary line 120 between the two adjacent positive electrode connecting sheets 110.

[0041] Each negative electrode connecting sheet 310 includes a third arcuate edge 3110, a third straight edge 3120, a fourth arcuate edge 3130, and a fourth straight edge 3140 connected end to end. The third straight edge 3120 of one of two adjacent negative electrode connecting sheets 310 is connected to the fourth straight edge 3140 of the other to form a negative electrode boundary line 320 between the two adjacent negative electrode connecting sheets 310.

[0042] In this embodiment, when the electrode module 10 is wound and folded to form a core, the two adjacent positive connecting sheets 110 are chamfered, that is, the first arcuate edge 1110 or the second arcuate edge 1130 between the two adjacent positive connecting sheets 110 is chamfered, which effectively reduces the stress on the positive electrode strip 100 when it is wound and folded, and avoids the occurrence of strip breakage during winding. Similarly, when the electrode module 10 is wound and folded to form a core, the two adjacent negative connecting sheets 310 are chamfered, that is, the third arcuate edge 3110 or the fourth arcuate edge 3130 between the two adjacent negative connecting sheets 310 is chamfered, which effectively reduces the stress on the positive electrode strip 100 when it is wound and folded, and avoids the occurrence of strip breakage during winding. Therefore, the winding speed of the core is effectively improved, thereby effectively improving the production efficiency of the core. Furthermore, the positive electrode boundary line 120 is used to form multiple positive electrode connecting sheets 110 into a positive electrode strip 100. Similarly, the negative electrode boundary line is used to form multiple negative electrode connecting sheets 310 into a negative electrode strip 300. Therefore, the winding function of the electrode module 10 can be realized. In addition, the positive electrode boundary line 120 and the negative electrode boundary line 320 make the electrode module 10 have better structural consistency during winding, thereby improving product quality consistency.

[0043] like Figure 2 As shown, in one embodiment, the maximum distance between the first arcuate edge 1110 and the second arcuate edge 1130 is defined as d, and the maximum distance between the third arcuate edge 3110 and the fourth arcuate edge 3130 is defined as D; the maximum distance d of the multiple positive electrode connecting plates 110 increases successively along the arrangement direction, and the maximum distance D of the multiple negative electrode connecting plates 310 increases successively along the arrangement direction.

[0044] In this embodiment, the number of positive electrode connecting pieces 110 and negative electrode connecting pieces 310 is the same, and the number of positive electrode connecting pieces 110 and negative electrode connecting pieces 310 is defined as n, where n = [1, 2, 3 ... i, (i + 1)], and n is a positive integer. The number of negative electrode connecting pieces 310 of the negative electrode strip 300 is an arithmetic progression D n =D1+(n-1)k gradually increases, and the positive electrode connecting piece 110 of the positive electrode strip 100 is an arithmetic progression d n =d1+(n-1)k gradually increases, where k is a constant. Specifically, in order for the negative electrode tape 300 to cover the positive electrode tape 100, as n increases, d nAs n increases, D n As n increases, the negative electrode connecting piece 310 gradually increases, resulting in the i+1th negative electrode connecting piece 310 covering the i-th negative electrode connecting piece 310. Therefore, as n increases, the negative electrode strip 300 always covers the positive electrode strip 100. Therefore, there is no need to use a multi-layer separator 200 to avoid the internal short circuit caused by the contact between the positive electrode strip 100 and the negative electrode strip 300, which effectively saves the use of the separator 200 and reduces the thickness of the electrode sheet of the core, thereby effectively reducing the production cost of the core.

[0045] like Figure 2 and Figure 3 As shown, in one embodiment, the first arcuate edge 1110 and the second arcuate edge 1130 are both circular arcuate edges; the third arcuate edge 3110 and the fourth arcuate edge 3130 are both circular arcuate edges.

[0046] In this embodiment, by configuring the first, second, third, and fourth arcuate edges 1110, 1130, 3110, and 3130 to be circular arcs, the rolled core forms a flat cylindrical battery cell after stamping. Because the negative electrode strip 300 overlies the positive electrode strip 100, the circular arcs on the surface of the rolled core after forming form the third and fourth arcuate edges 3110, 3130, of the nth negative electrode tab 310.

[0047] like Figures 1 to 3 As shown, the number of positive electrode connecting sheets 110 and negative electrode connecting sheets 310 is N, and the N positive electrode connecting sheets 110 are arranged in a one-to-one correspondence with the N negative electrode connecting sheets 310. The N positive electrode connecting sheets 110 form N-1 positive electrode boundary lines 120, and the N negative electrode connecting sheets 310 form N-1 negative electrode boundary lines 320. Each positive electrode boundary line 120 is arranged in a one-to-one correspondence with the corresponding negative electrode boundary line 320; N is an integer greater than 1.

[0048] In this embodiment, when N is an odd number and equal to 3, the N positive electrode connecting tabs 110 form N-1 positive electrode boundary lines 120, i.e., two positive electrode boundary lines 120, where N-1 is an even number and the first positive electrode boundary line 120 is parallel to the second positive electrode boundary line 120. Similarly, the N negative electrode connecting tabs 310 form N-1 negative electrode boundary lines 320, i.e., two negative electrode boundary lines 320, where N-1 is an even number and the first negative electrode boundary line 320 is parallel to the second negative electrode boundary line 320.

[0049] When N is an odd number and N is greater than 3, the N positive electrode connecting tabs 110 form N-1 positive electrode boundary lines 120, where N-1 is an even number, and the odd-numbered positive electrode boundary lines 120 are parallel to the even-numbered positive electrode boundary lines 120. The odd-numbered positive electrode boundary lines 120 continuously overlap as the odd number increases, and the even-numbered positive electrode boundary lines 120 continuously overlap as the even number increases. Similarly, the N negative electrode connecting tabs 310 form N-1 negative electrode boundary lines 320, where N-1 is an even number, and the odd-numbered negative electrode boundary lines 320 are parallel to the even-numbered negative electrode boundary lines 320. The odd-numbered negative electrode boundary lines 320 continuously overlap as the odd number increases, and the even-numbered negative electrode boundary lines 320 continuously overlap as the even number increases.

[0050] When N is an even number and equal to 2, the N positive electrode connecting tabs 110 form N-1 positive electrode boundary lines 120, where N-1 is an odd number, in which case only one positive electrode boundary line 120 is formed. Similarly, the N negative electrode connecting tabs 310 form N-1 negative electrode boundary lines 320, where N-1 is an odd number, in which case only one negative electrode boundary line 320 is formed.

[0051] When N is an even number and N is greater than 2, N positive electrode connecting plates 110 form N-1 positive electrode boundary lines 120, where N-1 is an odd number, the odd-numbered positive electrode boundary lines 120 are parallel to the even-numbered positive electrode boundary lines 120, the odd-numbered positive electrode boundary lines 120 continue to overlap as the odd number increases, and the even-numbered positive electrode boundary lines 120 continue to overlap as the even number increases, and there is one more odd-numbered positive electrode boundary line 120 than the even-numbered positive electrode boundary lines 120. Similarly, N positive electrode connecting plates 110 form N-1 positive electrode boundary lines 120, where N-1 is an odd number, the odd-numbered positive electrode boundary lines 120 are parallel to the even-numbered positive electrode boundary lines 120, the odd-numbered positive electrode boundary lines 120 are continuously superimposed and overlapped as the odd number increases, and the even-numbered positive electrode boundary lines 120 are continuously superimposed and overlapped as the even number increases, and there is one more odd-numbered positive electrode boundary line 120 than the even-numbered positive electrode boundary lines 120.

[0052] Furthermore, since the distance between the first straight edge 1120 and the second straight edge 1140 of the positive electrode connecting sheet 110 remains unchanged, the odd-numbered positive electrode boundary lines 120 continue to overlap and align one by one as the odd size increases, and the even-numbered positive electrode boundary lines 120 continue to overlap and align one by one as the odd size increases. Similarly, the distance between the third straight edge 3120 and the fourth straight edge 3140 of the negative electrode connecting sheet 310 remains unchanged, the odd-numbered negative electrode boundary lines 320 continue to overlap and align one by one as the odd size increases, and the even-numbered negative electrode boundary lines 320 continue to overlap and align one by one as the odd size increases. As a result, the electrode module 10 can be quickly and accurately aligned during winding and folding, without the need for secondary sorting and alignment, thereby effectively increasing the winding speed and thus effectively improving production efficiency.

[0053] like Figure 2 and Figure 3 As shown, in one embodiment, the positive electrode boundary lines 120 formed by every two adjacent positive electrode connecting sheets 110 are parallel to each other, and the negative electrode boundary lines 320 formed by every two adjacent negative electrode connecting sheets 310 are parallel to each other;

[0054] In this embodiment, since the winding core is formed by sequentially winding and folding the junction of each two adjacent positive electrode connecting sheets 110 along the arrangement direction of the multiple positive electrode connecting sheets 110, that is, winding and folding along the multiple positive electrode boundary lines 120, the positive electrode boundary lines 120 formed by each two adjacent positive electrode connecting sheets 110 are parallel to each other. Similarly, since the negative electrode connecting sheet 310 is arranged corresponding to the positive electrode sheet, when winding and folding along the multiple positive electrode boundary lines 120, the negative electrode boundary lines 320 formed by each two adjacent negative electrode connecting sheets 310 are also parallel to each other. As a result, the structure formed by the winding and folding of the winding core has good consistency, and there is no need for secondary sorting and alignment, which effectively saves production time and improves work efficiency. And / or,

[0055] In one embodiment, the positive electrode boundary line 120 is parallel to the negative electrode boundary line 320. In this embodiment, since the positive electrode strip 100, the separator 200, and the negative electrode strip 300 in the electrode module 10 are stacked sequentially, when the electrode module 10 is wound and folded along the multiple positive electrode boundary lines 120, the positive electrode strip 100 and the negative electrode strip 300 are simultaneously wound and folded to form a winding core. Therefore, the positive electrode boundary line 120 is parallel to the negative electrode boundary line 320, thereby ensuring good structural consistency of the winding and folding of the winding core, eliminating the need for secondary alignment, effectively saving production time and further improving work efficiency.

[0056] The present application also provides a process for preparing a pole piece module for manufacturing the pole piece module of any of the above-mentioned embodiments. The process for preparing a pole piece module includes some or all of the following steps: processing the positive electrode strip 100 and the negative electrode strip separately through a die-cutting process; laminating and pressing the negative electrode strip and the separator; placing the positive electrode strip on the side of the separator facing away from the negative electrode strip to form a pole piece assembly to be wound; and sequentially winding and folding the junction of each two adjacent positive electrode connecting strips along the arrangement direction of the multiple positive electrode connecting strips to obtain a winding core.

[0057] The above-mentioned pole piece module preparation process adopts the method of first die-cutting the pole piece module to obtain multiple positive electrode connecting sheets and multiple negative electrode connecting sheets, and then performing a hot pressing composite operation on the negative electrode strip and the diaphragm to obtain the pole piece module to be wound, thereby improving the stability of the pole piece module, so that the winding strip will not break easily and the negative electrode strip will not shift during winding, effectively improving the winding speed, and thus effectively improving the production efficiency of the core. The pole piece module is wound and folded, which can greatly simplify the process and avoid the situation where the pole piece is difficult to cut due to its thin thickness. Furthermore, the junction of each two adjacent positive electrode connecting sheets of the pole piece module to be wound is wound and folded in sequence along the arrangement direction of the multiple positive electrode connecting sheets, so that the structure of the core formed is more consistent, and there is no need to perform secondary sorting and alignment of the core, which not only effectively saves production time, but also greatly simplifies the process, thereby effectively improving production efficiency.

[0058] In order to better understand the electrode module manufacturing process of the present invention, the electrode module manufacturing process of the present invention is further explained below. Figure 4 As shown, a process for preparing a pole piece module according to one embodiment includes some or all of the following steps:

[0059] S100: The positive electrode strip and the negative electrode strip are processed separately through a die-cutting process.

[0060] In this embodiment, the positive electrode strip and the negative electrode strip are processed separately through the die-cutting process, that is, the positive electrode strip and the negative electrode strip are die-cut into n connected positive electrode connecting pieces and negative electrode connecting pieces, which solves the problem of the traditional flat large cylindrical battery manufacturing process that the electrode pieces cannot be cut due to their thin thickness.

[0061] S200: stacking the negative electrode strip and the separator and pressing and fixing them.

[0062] In this embodiment, since the negative electrode strip needs to cover the positive electrode strip, the separator only needs to overlap and fix it to form a separator bag to achieve the insulation effect, effectively separating the positive and negative electrode strips and preventing contact between the positive and negative electrode strips and internal short circuits. Furthermore, the pressing and fixing of the negative electrode strip and the separator makes the electrode module more stable, making it less likely to break during winding, thus avoiding the problem of tape breakage during winding, and effectively improving production efficiency.

[0063] S300: placing the positive electrode strip on the side of the separator facing away from the negative electrode strip to form a pole piece assembly to be wound.

[0064] In this embodiment, since the negative electrode strip always covers the positive electrode strip, the electrode module can achieve an insulation effect without the need for an extra diaphragm, which saves the use of diaphragm and reduces the thickness of the electrode of the core, effectively improving the energy density of the core and effectively reducing the production cost of the core.

[0065] S400 , winding and folding the electrode sheet assembly to be wound in sequence at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the plurality of positive electrode connecting sheets to obtain a winding core.

[0066] In this embodiment, the electrode assembly to be wound is wound and folded along the arrangement direction of multiple positive electrode connecting sheets with the first straight edge or the first axis of the first positive electrode connecting sheet as the axis to form a core. By die-cutting first and then winding, the problem that the flat large cylindrical special-shaped battery cannot be cut using the winding structure is solved. By sequentially winding and folding the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of multiple positive electrode connecting sheets of the wound electrode module, the structure of the core formed is more consistent, and there is no need to perform secondary sorting and alignment of the core, which not only effectively saves production time, but also greatly simplifies the process, thereby effectively improving production efficiency.

[0067] Furthermore, due to the good structural consistency and stability of the pole piece module, the pole piece module is not easy to break during the winding and folding process, which effectively solves the problem of easy breakage during winding, and then effectively improves the winding speed and winding success rate, thereby improving the production efficiency and product quality of the core.

[0068] In one embodiment, after the negative electrode tape and the separator are stacked and pressed together, the positive electrode tape is placed on the side of the separator away from the negative electrode tape to form the electrode assembly to be wound, and the following steps are also included: the negative electrode tape and the separator are heat-cut and welded. It should be noted that the separator is used to separate the positive electrode tape and the negative electrode tape to prevent the positive electrode tape and the negative electrode tape from contacting each other and causing an internal short circuit. However, since the negative electrode tape is arranged corresponding to the positive electrode tape and the negative electrode tape always covers the positive electrode tape, the size of the separator only needs to be consistent with the size of the negative electrode tape. When the positive electrode tape and the negative electrode tape are wound and folded into a core, the separator and the negative electrode tape need to be hot-pressed and composited, and then heat-cut and welded according to the size of the negative electrode tape. Therefore, no extra separator is required to achieve the insulation effect of the electrode module, saving the amount of separator used, effectively improving the energy density of the core and effectively reducing the production cost of the core.

[0069] In one of the embodiments, after the junction of each two adjacent positive connecting sheets of the wound electrode assembly along the arrangement direction of the multiple positive connecting sheets is sequentially wound and folded to obtain a core, the following steps are also included: stamping the core. It should be noted that after the junction of each two adjacent positive connecting sheets of the wound electrode assembly along the arrangement direction of the multiple positive connecting sheets is sequentially wound and folded to obtain a core, in order to obtain a flat cylindrical battery cell, it is also necessary to perform a stamping operation on the wound and folded core. The core is stamped by a stamping device to obtain a flat cylindrical battery cell, and then the flat cylindrical battery cell is welded to the pole ear, thereby completing the preparation of the core. By winding first and then stamping, the problem of difficult winding due to thin thickness of the electrode sheet and easy breakage of the winding strip is solved. Not only can the success rate of winding be improved, but also the preparation process can be simplified, thereby effectively improving production efficiency and production qualification rate.

[0070] In one embodiment, the diaphragm is one of a PMMA-coated diaphragm, a PVDF-coated diaphragm and a PE-coated diaphragm.

[0071] In this embodiment, the diaphragm is used to separate the positive electrode strip and the negative electrode strip to prevent the positive electrode strip and the negative electrode strip from contacting each other and causing an internal short circuit, and the PMMA coated diaphragm, PVDF diaphragm and PE coated diaphragm can ensure that the negative electrode strip and the diaphragm are effectively bonded and the negative electrode strip will not be displaced in the diaphragm bag, thereby avoiding the offset of the negative electrode strip during the winding process, effectively improving the structural consistency and stability of the electrode module, so the electrode module is not prone to tape breakage during the winding process, effectively solving the problem of easy tape breakage during winding, and then effectively improving the winding speed and winding success rate, thereby improving the production efficiency and product quality of the core.

[0072] Compared with the prior art, the present invention has at least the following advantages:

[0073] 1. The core formed by the electrode module of the present invention is sequentially wound and folded along the arrangement direction of the multiple positive electrode connecting tabs at the junction of each two adjacent positive electrode connecting tabs, resulting in a highly consistent core structure and improved product quality. Furthermore, by aligning each positive electrode connecting tab with the corresponding negative electrode connecting tab, the core can be insulated without the need for multiple layers of separators, effectively preventing internal short circuits caused by contact between the positive and negative electrode strips. This also reduces the amount of separator used, effectively increasing the energy density of the core and reducing its production cost.

[0074] 2. The pole piece module preparation process of the present invention adopts the method of first die-cutting the pole piece module to obtain a plurality of positive electrode connecting sheets and a plurality of negative electrode connecting sheets, and then performing a hot pressing composite operation on the negative electrode strip and the diaphragm to obtain the pole piece module to be wound, thereby improving the stability of the pole piece module, so that the situation of the winding strip being easily broken and the negative electrode strip being offset during winding will not occur, effectively improving the winding speed, and thus effectively improving the production efficiency of the core. The pole piece module is wound and folded, which can greatly simplify the process and avoid the situation where the pole piece is difficult to cut due to its thin thickness. Furthermore, the junction of each two adjacent positive electrode connecting sheets of the pole piece module to be wound is wound and folded in sequence along the arrangement direction of the multiple positive electrode connecting sheets, so that the structure of the core formed is more consistent, and there is no need to perform secondary sorting and alignment on the core, which not only effectively saves production time, but also greatly simplifies the process, thereby effectively improving production efficiency.

[0075] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A pole piece module manufactured using a pole piece module manufacturing process, in the form of a core roll, characterized in that: The winding core comprises a positive electrode strip, a separator and a negative electrode strip stacked in sequence; The positive electrode strip includes a plurality of positive electrode connecting sheets connected in sequence, and the negative electrode strip includes a plurality of negative electrode connecting sheets connected in sequence, each positive electrode connecting sheet is arranged correspondingly to the corresponding negative electrode connecting sheet; the winding core is sequentially wound and folded at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the plurality of positive electrode connecting sheets; Each of the positive electrode connecting sheets includes a first arcuate side, a first straight side, a second arcuate side, and a second straight side connected end to end in sequence, and the first straight side of one of two adjacent positive electrode connecting sheets is connected to the second straight side of the other to form a positive electrode boundary line between the two adjacent positive electrode connecting sheets; Each of the negative electrode connecting sheets includes a third arcuate side, a third straight side, a fourth arcuate side, and a fourth straight side connected end to end in sequence, and the third straight side of one of two adjacent negative electrode connecting sheets is connected to the fourth straight side of the other to form a negative electrode boundary line between the two adjacent negative electrode connecting sheets; The maximum distance between the first arcuate side and the second arcuate side is defined as d, and the maximum distance between the third arcuate side and the fourth arcuate side is defined as D; The maximum distance d between the plurality of positive electrode connecting sheets increases sequentially along the arrangement direction, and the maximum distance D between the plurality of negative electrode connecting sheets increases sequentially along the arrangement direction; The pole piece module is manufactured using a module preparation process, which includes the following steps: Processing the positive electrode strip and the negative electrode strip respectively through a die-cutting process; Laminating the negative electrode tape and the separator and pressing and fixing them; Arranging the positive electrode strip on the side of the separator away from the negative electrode strip to form a pole piece assembly to be wound; The electrode assembly to be wound is sequentially wound and folded at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the plurality of positive electrode connecting sheets to obtain a winding core.

2. The pole piece module manufactured by the pole piece module manufacturing process according to claim 1, characterized in that: The first arc-shaped edge and the second arc-shaped edge are both circular arc-shaped edges; The third arc-shaped edge and the fourth arc-shaped edge are both circular arc-shaped edges.

3. The pole piece module manufactured by the pole piece module manufacturing process according to claim 1, characterized in that: The number of the positive electrode connecting sheets and the number of the negative electrode connecting sheets are both N, and the N positive electrode connecting sheets are arranged in a one-to-one correspondence with the N negative electrode connecting sheets. The N positive electrode connecting sheets form N-1 positive electrode boundary lines, and the N negative electrode connecting sheets form N-1 negative electrode boundary lines. Each positive electrode boundary line is arranged in a one-to-one correspondence with the corresponding negative electrode boundary line; N is an integer greater than 1.

4. The pole piece module manufactured by the pole piece module manufacturing process according to claim 1, characterized in that: The positive electrode boundary lines formed by every two adjacent positive electrode connecting sheets are parallel to each other, and the negative electrode boundary lines formed by every two adjacent negative electrode connecting sheets are parallel to each other; and / or, The positive electrode boundary line is parallel to the negative electrode boundary line.

5. The pole piece module manufactured by the pole piece module manufacturing process according to claim 1, characterized in that: After the negative electrode tape and the separator are stacked and pressed together, the positive electrode tape is placed on the side of the separator facing away from the negative electrode tape to form the electrode assembly to be wound, and the following steps are also included: The negative electrode strip and the separator are heat-cut and sealed.

6. The pole piece module manufactured by the pole piece module manufacturing process according to claim 1, characterized in that: After the electrode assembly to be wound is wound and folded in sequence at the junction of each two adjacent positive electrode connecting sheets along the arrangement direction of the plurality of positive electrode connecting sheets to obtain a winding core, the following steps are further included: A punching operation is performed on the core.

7. The pole piece module manufactured by the pole piece module manufacturing process according to claim 5, characterized in that: The diaphragm is one of a PMMA coating diaphragm, a PVDF coating diaphragm and a PE coating diaphragm.

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