Thermally-lamintaed stacked cell and battery

Abstract

Disclosed in the present application are a thermally-laminated stacked cell and a battery. The thermally-laminated stacked cell is formed by folding a laminated cell. The laminated cell comprises a first separator, a second separator, first electrode sheets and second electrode sheets, wherein part of the structures of the first separator and the second separator are fixedly connected to form a plurality of pouch-type structures having openings; the first electrode sheets are correspondingly disposed inside the pouch-type structures; and in the direction of length of the laminated cell, the second electrode sheets are alternately arranged on the sides of the first separator and the second separator away from the first electrode sheets.

Description

Thermal composite laminated cells and batteries

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on April 3, 2024, with application number 202420693476.7. The entire contents of the above application are incorporated by reference into this application. Technical Field

[0002] The present application belongs to the field of battery technology, and in particular relates to a thermal composite laminated battery cell and a battery. Background Art

[0003] The battery cell is the core structure of the battery, consisting of a positive electrode, a negative electrode, and a separator. The cell manufacturing process involves thermally laminating the positive, negative, and separator into a thermally composited monomer, which is then stacked in a Z-shape to form the battery cell. In the thermally composited monomer, the separator is completely thermally laminated to the sides of the negative or positive electrode, and the separator is pressed very tightly against the negative and positive electrodes. This makes later electrolyte injection difficult and increases injection time. This also increases the difficulty of electrolyte infiltration, affecting the overall battery performance. SUMMARY OF THE INVENTION

[0004] An embodiment of the present application provides a thermal composite laminated cell and battery, in which a bag-type structure is formed by partially bonding a first diaphragm and a second diaphragm, and a first electrode is installed in the bag-type structure. The first electrode is not directly bonded to the diaphragms on both sides, thereby achieving the technical effect of facilitating the injection of electrolyte and facilitating the infiltration of electrolyte.

[0005] In a first aspect, an embodiment of the present application provides a thermal composite laminated battery core, wherein the thermal composite laminated battery core is formed by folding a composite monomer, wherein the composite monomer comprises:

[0006] first diaphragm;

[0007] a second diaphragm, wherein the first diaphragm and the second diaphragm are stacked, and portions of the first diaphragm and the second diaphragm are fixedly connected to form a plurality of bag-like structures having openings, wherein the plurality of bag-like structures are spaced apart along the length direction of the composite unit;

[0008] A plurality of first pole pieces, wherein the plurality of first pole pieces are placed in the plurality of bag-type structures in a one-to-one correspondence;

[0009] A plurality of second pole pieces, wherein the polarity of the first pole piece is opposite to that of the second pole piece, and along the length direction of the composite unit, the second pole pieces are alternately arranged on the side of the first diaphragm away from the first pole piece and the side of the second diaphragm away from the first pole piece.

[0010] In a second aspect, an embodiment of the present application further provides a battery comprising any one of the thermal composite laminated battery cells described above. Beneficial effects

[0011] The foldable battery cell provided in the embodiment of the present application is formed by a composite monomer through Z-shaped folding, wherein the composite monomer includes a continuous first diaphragm, a second diaphragm, multiple first pole pieces and multiple second pole pieces, and partial structures of the first diaphragm and the second diaphragm are fixedly connected to form multiple bag structures with openings, and the multiple bag structures are arranged at intervals, and the first pole pieces are placed in the bag structures one by one, and the second pole pieces are alternately arranged on the outside of the first diaphragm and the second diaphragm. The first pole piece is fixed between the first diaphragm and the second diaphragm through the bag structure, and the first pole piece is not directly bonded to the first diaphragm and the second diaphragm, thereby overcoming the problem that the existing composite laminated battery cell is compressed due to heat and the positive electrode piece or the negative electrode piece, resulting in difficulty in electrolyte injection and high difficulty in electrolyte infiltration, facilitating later electrolyte injection, and being beneficial to electrolyte infiltration, thereby improving the overall performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG1 is a top view of a composite cell in a thermal composite laminated battery cell provided in an embodiment of the present application.

[0013] FIG2 is a partial schematic diagram of the AA section in FIG1 .

[0014] FIG3 is a partial schematic diagram of the BB section in FIG1 .

[0015] FIG4 is a partial enlarged view of point C in FIG3 .

[0016] FIG5 is a top view of the thermal composite laminated battery cell provided in an embodiment of the present application.

[0017] FIG6 is a partial schematic diagram of the DD section in FIG5 .

[0018] FIG7 is a partial enlarged view of a composite unit in a thermal composite laminated battery cell in which an incompletely cut structure is provided and the incompletely cut structure is a circular through hole.

[0019] FIG8 is a partial enlarged view of a composite unit in a thermal composite laminated battery cell in which an incompletely cut structure is provided and the incompletely cut structure is a rectangular through hole.

[0020] FIG9 is a partially enlarged cross-sectional view of a thermally composite laminated battery cell formed by folding a composite monomer along an incompletely cut structure.

[0021] Description of reference numerals:

[0022] 100. Composite monomer; 110. First diaphragm; 120. Second diaphragm; 130. First pole piece; 131. First pole tab; 132. First side; 133. Bottom; 134. Second side; 135. Top; 140. Second pole piece; 141. Second pole tab; 150. Bag-type structure; 151. Opening; 152. Pressed portion; 160. Incompletely cut structure; 161. Through hole; 200. Thermal composite laminated cell. Modes for Carrying Out the Invention

[0023] Referring to Figures 1, 2, 3, 4, 5, and 6, an embodiment of the present application provides a thermally composite laminated battery cell 200 formed by folding a composite unit 100 in a Z-shape. The composite unit 100 includes a first separator 110, a second separator 120, a plurality of first electrode sheets 130, and a plurality of second electrode sheets 140. The battery cell can be used as an energy storage unit in a battery, which can convert the energy stored in the cell into current and supply it to electronic devices.

[0024] In this embodiment, as shown in FIG1 , the first diaphragm 110 and the second diaphragm 120 are continuous strip structures. The first diaphragm 110 and the second diaphragm 120 have the same shape and size and are arranged parallel to each other. Partial structures of the first diaphragm 110 and the second diaphragm 120 are fixedly connected to form a plurality of bag-like structures 150 having openings 151. The plurality of bag-like structures 150 are arranged in sequence along the length of the first diaphragm 110.

[0025] In this embodiment, as shown in FIG1 , the first electrode piece 130 is a rectangular sheet structure. A first electrode tab 131 is provided on one side of the first electrode piece 130. The first electrode tab 131 is a trapezoidal sheet structure. The size of the side where the first electrode tab 131 is connected to the first electrode piece 130 is larger than the size of the other side. A plurality of first electrode pieces 130 are arranged in a plurality of pocket structures 150 in a one-to-one correspondence. The pocket structures 150 correspond to the first electrode pieces 130 in a one-to-one correspondence, and each first electrode piece 130 is arranged in a corresponding pocket structure 150. For example, at least a portion of the first electrode tab 131 can extend from the opening 151 outside the first diaphragm 110 and the second diaphragm 120. All the first electrode tabs 131 are located on the same side of the first diaphragm 110. The first electrode piece 130 is fixed between the first diaphragm 110 and the second diaphragm 120 by the pocket structure 150, but the first electrode piece 130 is not bonded to the diaphragms on both sides.

[0026] In this embodiment, as shown in FIG1 , the second pole piece 140 is a rectangular sheet structure. A second pole piece 141 is provided on one side of the second pole piece 140. The second pole piece 141 is a trapezoidal sheet structure. The length of the side where the second pole piece 141 is connected to the second pole piece 140 is greater than the length of the other side. The second pole piece 141 at least partially extends outward from the first diaphragm 110 and the second diaphragm 120. Along the length direction of the first diaphragm 110, the second pole piece 140 is alternately arranged on the side of the first diaphragm 110 facing away from the first pole piece 130 and the side of the second diaphragm 120 facing away from the first pole piece 130. The first pole piece 130 and the second pole piece 140 are arranged in alignment. The second pole piece 140 and the first pole piece 130 have opposite polarities, the first pole piece 130 and the first pole piece 131 have the same polarity, and the second pole piece 140 and the second pole piece 141 have the same polarity. Illustratively, the polarity of the first electrode piece 130 and the first electrode tab 131 is positive, and the polarity of the second electrode piece 140 and the second electrode tab 141 is negative; or, the polarity of the first electrode piece 130 and the first electrode tab 131 is negative, and the polarity of the second electrode piece 140 and the second electrode tab 141 is positive.

[0027] It can be understood that in this embodiment, the first electrode piece 130 is fixed between the first diaphragm 110 and the second diaphragm 120 by the bag structure 150. The first electrode piece 130 and the first diaphragm 110 and the second diaphragm 120 on both sides are in a non-fitted state, and the first electrode piece 130 is not pressed. This overcomes the problem that the existing thermal composite laminated battery cell presses the positive electrode piece or the negative electrode piece, resulting in difficulty in electrolyte injection and high difficulty in electrolyte infiltration. It facilitates the later electrolyte injection, is beneficial to the infiltration of the electrolyte, and improves the overall performance of the battery.

[0028] In some embodiments, as shown in Figures 2, 3, and 4, the bag-type structure 150 includes a press-fit portion 152 provided along the circumferential side of the first electrode sheet 130 where the first electrode tab 131 is not provided. The first diaphragm 110 and the second diaphragm 120 are bonded together at the position of the press-fit portion 152. As long as the first diaphragm 110 and the second diaphragm 120 are partially in contact, it can be considered that the first diaphragm 110 and the second diaphragm 120 are bonded together.

[0029] It can be understood that in this embodiment, a pressing portion 152 is provided along the circumferential side of the first pole piece 130 where the first pole ear 131 is not provided. The shape of the bag-type structure 150 formed by the pressing portion 152 is adapted to the shape of the first pole piece 130, thereby reducing waste of diaphragm materials and lowering production costs.

[0030] In some embodiments, as shown in Figures 2 and 3 , the press-fit portion 152 extends and is continuously disposed along the circumference of the first pole piece 130. In this embodiment, the press-fit portion 152 is a continuous press-fit line that is continuously disposed along the circumference of the first pole piece 130, fully enclosing the first pole piece 130 except for the first tab 131. This prevents contact between adjacent first pole pieces 130 in the composite cell 100 and improves the reliability of the thermally composite laminated battery cell. The press-fit portion 152 located on the same side of the first pole piece 130 can include multiple press-fit lines, with adjacent press-fit lines spaced apart, or a single press-fit line of a certain width can be provided.

[0031] Alternatively, the press-fit portion 152 may be a plurality of disconnected bonding points arranged along the circumference of the first electrode 130. At these bonding points, the first diaphragm 110 and the second diaphragm 120 are bonded and connected, while at other locations, the first diaphragm 110 and the second diaphragm 120 are disconnected. The bonding points form a pocket structure 150, ensuring the structural strength of the diaphragm. Furthermore, the distance between any two adjacent bonding points is uniform, facilitating bonding point processing.

[0032] For example, the first diaphragm 110 and the second diaphragm 120 are fitted and connected at the pressing portion 152 . As long as a portion of the structure of one of the diaphragms contacts the other diaphragm, the two diaphragms can be considered to be fitted and connected.

[0033] In some embodiments, referring to Figures 2 and 3, the first pole piece 130 includes a first side 132, a bottom 133, a second side 134 and a top 135. The first side 132 and the second side 134 are arranged opposite to each other, the top 135 is provided with a first pole ear 131, and the bottom 133 and the top 135 are arranged opposite to each other, wherein the first side 132 and the second side 134 have the same size, and the top 135 and the bottom 133 have the same size. The first pole piece 130 is a rectangular sheet with a regular shape for easy processing.

[0034] In some embodiments, as shown in FIG2 , the width of the pressing portion 152 on the side of the first side 132 is the same as the width of the pressing portion 152 on the side of the second side 134. The pressing portion 152 on the side of the first side 132 refers to a section of the pressing portion 152 close to the first side 132, and the pressing portion 152 on the side of the second side 134 refers to a section of the pressing portion 152 close to the second side 134. The width refers to the vertical distance between the side of the first pole piece 130 and the side of the pressing portion 152 on the side of the first pole piece 130.

[0035] In this embodiment, the pressing portion 152 on the first side 132 and the pressing portion 152 on the second side 134 have the same width, which facilitates processing and ensures that the structural strength of the diaphragms on both sides of the first electrode piece 130 is the same.

[0036] In some embodiments, as shown in Figures 2 and 4 , the width of the press-fit portion 152 on the side where the first side 132 is located is D1, and 4mm≤D1≤10mm. The value of D1 can be 4mm, 6mm, 7mm, 9mm, 10mm, or other values ​​therein. In this embodiment, the press-fit portion 152 on the side where the first side 132 is located is shaped like a straight line with a certain line width. The width of the press-fit portion 152 refers to the minimum distance between one edge of the press-fit portion 152 and the other edge of the press-fit portion 152 along the length direction of the first diaphragm 110.

[0037] In some embodiments, as shown in Figures 2 and 4 , the width of the press-fit portion 152 on the side where the second side 134 is located is D2, where 4mm≤D2≤10mm. The value of D2 can be 4mm, 6mm, 7mm, 9mm, 10mm, or other suitable values. In this embodiment, the press-fit portion 152 on the side where the second side 134 is located is shaped like a straight line with a certain line width. The width of the press-fit portion 152 refers to the minimum distance between one edge of the press-fit portion 152 and the other edge of the press-fit portion 152 along the length direction of the first diaphragm 110.

[0038] It can be understood that along the extension direction of the first side 132 or the second side 134, the width of the pressing portion 152 on the side where the first side 132 or the second side 134 is located can be the same or different, such as the width of the pressing portion 152 gradually increases or decreases from one end to the other end of the first side 132, or the width of the pressing portion 152 near the two ends is greater than the width near the middle position.

[0039] In some embodiments, as shown in FIG3 , the width of the pressing portion 152 on the side of the bottom edge 133 is the same as the width of the pressing portion 152 on the side of the top edge 135. The pressing portion 152 on the side of the bottom edge 133 refers to a section of the pressing portion 152 close to the bottom edge 133. Similarly, the pressing portion 152 on the side of the top edge 135 refers to a section of the pressing portion 152 close to the top edge 135. The width refers to the vertical distance between the bottom edge or top edge of the first pole piece 130 and the side edge of the pressing portion 152 on that side.

[0040] In this embodiment, the pressing portion 152 on the side where the bottom edge 133 is located has the same width as the pressing portion 152 on the side where the top edge 135 is located, which facilitates processing and ensures that the structural strength of the pressing portions 152 at both ends of the first pole piece 130 is the same.

[0041] In some embodiments, as shown in FIG3 , the width of the pressing portion 152 on the side where the bottom edge 133 is located is D3, 2mm≤D3≤5mm. The value of D3 can be 2mm, 2.3mm, 2.7mm, 3mm, 3.5mm, 4.2mm, 4.8mm or 5mm.

[0042] In some embodiments, as shown in FIG3 , the width of the pressing portion 152 on the side where the top edge 135 is located is D4, 2mm≤D3≤5mm. The value of D4 can be 2mm, 2.5mm, 3.3mm, 3.5mm, 4mm, 4.6mm or 5mm.

[0043] It can be understood that along the extension direction of the bottom edge 133 or the top edge 135, the width of the pressing portion 152 on the side where the bottom edge 133 or the top edge 135 is located can be the same or different, such as the width of the pressing portion 152 gradually increases or decreases from one end to the other end of the bottom edge 133, or the width of the pressing portion 152 near the two ends is greater than the width near the middle position.

[0044] In this embodiment, the first electrode piece 130 is completely covered by the first diaphragm 110 and the second diaphragm 120, preventing contact between the first electrode piece 130 and the second electrode piece 140. This meets the electrical safety requirements of the thermal composite laminated cell and improves the reliability of the thermal composite laminated cell. The dimensions of the press-fit portion 152 are reasonably designed to meet the structural performance requirements while avoiding excessive size of the press-fit portion 152, which would waste diaphragm material.

[0045] In some embodiments, as shown in FIG. 2 , FIG. 3 and FIG. 6 , the first diaphragm 110 and the second diaphragm 120 are thermally composited and connected at the press-fit portion 152 .

[0046] It can be understood that during the processing of the composite monomer 100, the first pole piece 130 is located between the first diaphragm 110 and the second diaphragm 120, and the first pole piece 130 moves with the first diaphragm 110 and the second diaphragm 120. During the movement of the first pole piece 130, the first diaphragm 110, the second diaphragm 120 and the first pole piece 130 pass through a pair of hot pressing rollers, and a hot composite processing technology is used to thermally composite the first diaphragm 110 and the second diaphragm 120 at the pressing part 152. The processing technology is simple and the processing efficiency is improved.

[0047] In some embodiments, as shown in Figures 2, 3, and 6, the second pole piece 140 is thermally composited with the first diaphragm 110 and the second diaphragm 120. One side of the second pole piece 140 is bonded to the side of the first diaphragm 110 or the second diaphragm 120 through a thermal composite process to ensure that the second pole piece 140 is firmly connected to the first diaphragm 110 or the second diaphragm 120, thereby preventing the second pole piece 140 from falling off. At the same time, the other side of the second pole piece 140 is not bonded to any diaphragm, and the second pole piece 140 is not compressed, which facilitates the subsequent electrolyte injection, promotes the infiltration of the electrolyte, and improves the overall performance of the battery. Exemplarily, the thermal composite process is as follows: the positive electrode material roll, the negative electrode material roll and the separator are fed at the same time. Before entering the heating device, the positive electrode sheet and the negative electrode sheet are cut into single electrode sheets of the required size by a cutter. The combination of the positive electrode sheet, the negative electrode sheet and the separator enters the heating system under the action of rollers. The first separator 110 and the second separator 120 on the side of the first electrode sheet 130 where the first electrode tab 131 is not provided are thermally bonded. The second electrode sheet 140 after baking is thermally composited with the separator, and then rolled and cut to form a composite monomer.

[0048] In some embodiments, as shown in FIG. 7 , FIG. 8 and FIG. 9 , an incompletely cut structure 160 is provided on the pressing portion 152 between adjacent first pole pieces 130 , and the composite unit 100 is folded along the incompletely cut structure 160 .

[0049] It can be understood that in this embodiment, an incompletely cut structure 160 is provided on the first diaphragm 110 and the second diaphragm 120, so that the stress at the incompletely cut structure 160 is relatively small during the folding process of the composite monomer 100. The incompletely cut structure 160 can release the stress generated by folding, so that the first diaphragm 110 and the second diaphragm 120 are easy to fold at the incompletely cut structure 160, thereby playing the role of limiting the folding position and improving the folding quality and folding efficiency. It is beneficial to align the first electrode 130 and the second electrode 140, and improves the alignment of the thermal composite laminated battery cell. It avoids the lithium ions released from the positive electrode sheet from being unable to be completely embedded in the negative electrode sheet due to the misalignment of the first electrode sheet 130 and the second electrode sheet 140. The lithium ions that cannot be embedded can only obtain electrons on the surface of the negative electrode sheet to form white metallic lithium, and the occurrence of lithium plating piercing the diaphragm, thereby ensuring the stable performance of the folded battery cell.

[0050] In some embodiments, as shown in FIG7 , the incompletely cut structure 160 includes a plurality of through holes 161 extending through the pressing portion 152 , with the plurality of through holes 161 spaced apart along the width direction Y of the composite unit 100 . Alternatively, the plurality of through holes 161 are arranged in an array, with multiple rows of through holes 161 arranged along the length direction X of the composite unit 100 . Each row of through holes 161 can be arranged along the width direction Y of the composite unit 100 . For example, the arrangement directions of the multiple rows of through holes 161 can be parallel to each other. In other embodiments, the arrangement direction of at least one row of through holes 161 can be at an angle to the arrangement direction of the other rows of through holes. For example, the angle can be less than or equal to 10°, for example, 1°, 2°, 5°, etc. In other embodiments, the angle can be greater than 10°, and the embodiments of the present application are not limited thereto. For example, the plurality of through holes 161 in one of any two rows of through holes 161 can be arranged one-to-one opposite the plurality of through holes 161 in the other row. In other embodiments, at least one row of through holes 161 may be staggered with another row of through holes 161. Two through holes 161 may be considered staggered if their projections along the length direction X of the composite unit 100 do not overlap. For example, the through holes 161 in one of two adjacent rows of through holes 161 may be staggered with the through holes 161 in the other row.

[0051] In some other embodiments, the incompletely cut structure 160 may also include a plurality of slits spaced apart from each other. The slits may be formed by cutting the diaphragm with a knife or the like. In addition, the incompletely cut structure 160 may also be a textured structure.

[0052] It can be understood that by arranging multiple through holes 161 on the pressing part 152 to form an incompletely cut structure 160, local material on the pressing part 152 is cut off, and along the width direction Y of the composite unit 100, the pressing part 152 is not completely cut, so that the pressing part 152 around the through hole 161 is weak. When the composite unit 100 is folded by free fall, the composite unit 100 will fold along the straight line where the through hole 161 is located, which is beneficial to the alignment of the first electrode 130 and the second electrode 140 in the folded battery cell.

[0053] 7 and 8 , the intervals between adjacent through holes 161 are the same. The interval between adjacent through holes 161 refers to the distance between one side of a through hole 161 and another side of an adjacent through hole 161 along the width direction of the composite unit 100 .

[0054] In this embodiment, the intervals between adjacent through holes 161 are the same, which is conducive to processing the through holes 161 on the composite monomer 100, so that the strength of the diaphragm on the straight line where the multiple through holes 161 are located is the same, avoiding the situation where the diaphragm is pulled apart during the folding process due to local weak strength.

[0055] 7 and 8 , the through hole 161 is in a regular shape such as a circle, rectangle, ellipse, hexagon or octagon. In addition to being in a regular shape, the through hole 161 can also be in an irregular shape.

[0056] In some embodiments, as shown in FIG7 and FIG8 , the interval between adjacent through holes 161 is S1, where 5 mm ≤ S1 ≤ 20 mm. The value of S1 can be 5.0 mm, 5.2 mm, 5.7 mm, 7.8 mm, 9.0 mm, 10.5 mm, 11.5 mm, 12.3 mm, 13.9 mm, 14.0 mm, 15.7 mm, 16.1 mm, 17.4 mm, 18.0 mm, 19.6 mm, 20.0 mm, or other values ​​not specified.

[0057] It can be understood that the spacing distance between the through holes 161 in this embodiment is reasonably designed to avoid the situation where the distance between the through holes 161 is too small and the number of through holes 161 is too large, which affects the structural strength of the composite monomer 100. It also avoids the situation where the distance between the through holes 161 is too large and the number of through holes 161 is too small, which fails to play a role in positioning and folding during the folding process.

[0058] In some embodiments, as shown in FIG8 , through-hole 161 is rectangular and has a first dimension L1 and a second dimension W1. The first dimension is the distance between two parallel planes that virtually abut the two side walls of through-hole 161, and the second dimension is the distance between two parallel planes that virtually abut the two end walls of through-hole 161. Here, 1 mm ≤ L1 ≤ 20 mm, and / or 1 mm ≤ W1 ≤ 2 mm. The two side walls refer to the side walls extending along the width direction Y of the first diaphragm 110, and the two end walls refer to the side walls extending along the length direction X of the composite unit 100. In this embodiment, the value of L1 can be 1.1 mm, 1.2 mm, 1.5 mm, 2.3 mm, 3.4 mm, 4.2 mm, 5.0 mm, 6.8 mm, 7.8 mm, 8.8 mm, 9.0 mm, 10.3 mm, 11.1 mm, 12.5 mm, 13.8 mm, 14.1 mm, 15.0 mm, 16.6 mm, 17.7 mm, 18.2 mm, 19.1 mm, 20.0 mm, or other unspecified values. In this embodiment, the value of W1 can be 1.1 mm, 1.2 mm, 1.4 mm, 1.5 mm, 1.8 mm, 2.0 mm, or other unspecified values.

[0059] It should be noted that the two parallel planes virtually abutting the through-hole 161 are introduced only to facilitate understanding of the first and second dimensions and do not actually exist in the present application. For example, if the through-hole 161 has a rectangular outer contour, to determine the first and second dimensions, two sets of planes can be hypothesized, each set of planes comprising two spaced-apart parallel planes, with the two parallel planes in each set being able to virtually abut two opposing walls of the through-hole 161. In this case, a distance exists between the two parallel planes in each set: the first dimension is the distance between the two planes abutting the two side walls of the through-hole 161, and the second dimension is the distance between the two planes abutting the two end walls of the through-hole 161.

[0060] It can be understood that the size of the through hole 161 in this embodiment is reasonably designed to avoid affecting the structural strength of the composite unit 100 due to the through hole 161 being too large, or failing to play a role in positioning and folding during the folding process due to the through hole 161 being too small.

[0061] In some embodiments, the first electrode 130 is a negative electrode or a positive electrode, and the second electrode 140 is a positive electrode or a negative electrode.

[0062] Exemplarily, if the first electrode 130 is a negative electrode, the corresponding second electrode 140 is a positive electrode; if the first electrode 130 is a positive electrode, the corresponding second electrode 140 is a negative electrode.

[0063] In some embodiments, as shown in Figure 9 , the length of the negative electrode sheet is greater than the length of the positive electrode sheet, and the width of the negative electrode sheet is greater than the width of the positive electrode sheet. In the thermally laminated cell, along the thickness Z direction of the negative electrode sheet, the projection of the positive electrode sheet in the thickness direction falls completely within the plane area where the negative electrode sheet is located.

[0064] It is understandable that if the first electrode 130 is a negative electrode and the second electrode 140 is a positive electrode, the length of the first electrode 130 is greater than the length of the second electrode 140, and the width of the first electrode 130 is greater than the width of the second electrode 140; if the first electrode 130 is a positive electrode and the second electrode 140 is a negative electrode, the length of the first electrode 130 is less than the length of the second electrode 140, and the width of the first electrode 130 is less than the width of the second electrode 140. By designing the size of the negative electrode to be larger than that of the positive electrode, during the charging process of the lithium battery, the negative electrode can fully receive the lithium ions of the positive electrode, reducing the probability of lithium dendrite formation, thereby avoiding the situation where the formation of lithium dendrites pierces the composite cell 100, resulting in a short circuit and thermal runaway, thereby improving the reliability of the battery.

[0065] In some embodiments, the composite unit 100 includes N first pole pieces 130 and M second pole pieces 140 , where N and M are both positive integers greater than 1. When the first pole piece 130 is a negative pole piece and the second pole piece 140 is a positive pole piece, NM=1.

[0066] It can be understood that, as shown in Figures 6 and 9, along the thickness direction Z of the thermal composite laminated battery cell, the first electrode sheets 130 and the second electrode sheets 140 are alternately arranged, and the number of negative electrode sheets is one more than the number of positive electrode sheets. The two outermost electrode sheets of the thermal composite laminated battery cell are both negative electrode sheets, which meets the electrical requirements of the battery.

[0067] In some embodiments, the composite unit 100 includes N first pole pieces and M second pole pieces, where N and M are both positive integers greater than 1. When the first pole piece 130 is a positive pole piece and the second pole piece 140 is a negative pole piece, MN=1.

[0068] It can be understood that along the thickness direction Z of the thermal composite laminated battery cell, the first electrode sheet 130 and the second electrode sheet 140 are alternately arranged, and the number of negative electrode sheets is one more than the number of positive electrode sheets. The two outermost electrode sheets of the thermal composite laminated battery cell are both negative electrode sheets, which meets the electrical requirements of the battery.

[0069] The embodiment of the present application further provides a battery including a thermal composite laminated battery core 200. The battery has the same technical effects as the thermal composite laminated battery core 200, and the embodiment of the present application will not be repeated.

Claims

1. A thermal composite laminated battery core, wherein the thermal composite laminated battery core is formed by folding a composite monomer (100), wherein the composite monomer (100) comprises: a first diaphragm (110); a second diaphragm (120), wherein the first diaphragm (110) and the second diaphragm (120) are stacked, and partial structures of the first diaphragm (110) and the second diaphragm (120) are fixedly connected to form a plurality of bag-type structures (150) having openings (151), and the plurality of bag-type structures (150) are spaced apart along the length direction of the composite monomer (100); a plurality of first pole pieces (130), wherein the plurality of first pole pieces (130) are placed in the plurality of bag-type structures (150) in a one-to-one correspondence; A plurality of second pole pieces (140), wherein the first pole piece (130) and the second pole piece (140) have opposite polarities, and along the length direction of the composite monomer (100), the second pole pieces (140) are alternately arranged on a side of the first diaphragm (110) facing away from the first pole piece (130) and a side of the second diaphragm (120) facing away from the first pole piece (130).

2. The thermal composite laminated battery cell according to claim 1, wherein: A first pole tab (131) is provided on one side of the first pole piece (130), and the first pole tab (131) at least partially extends from the opening (151) to the outside of the first diaphragm (110) and the second diaphragm (120).

3. The thermal composite laminated battery cell according to claim 1 or 2, wherein: The bag-type structure (150) comprises a pressing portion (152) provided along a peripheral side of the first electrode sheet (130) where the first electrode tab (131) is not provided, and the first diaphragm (110) and the second diaphragm (120) are bonded and connected at the pressing portion (152).

4. The thermal composite laminated battery cell according to claim 3, wherein: The pressing portion (152) extends along the circumference of the first pole piece (130) and is continuously arranged.

5. The thermal composite laminated battery cell according to any one of claims 1 to 4, wherein: The first pole piece (130) comprises a first side edge (132), a bottom edge (133), a second side edge (134) and a top edge (135); the first side edge (132) and the second side edge (134) are arranged opposite to each other; the bottom edge (133) and the top edge (135) are arranged opposite to each other; and the first pole tab (131) is arranged on the top edge (135).

6. The thermal composite laminated battery cell according to claim 5, wherein: The width of the pressing portion (152) on the side where the first side (132) is located and the width of the pressing portion (152) on the side where the second side (134) is located are the same.

7. The thermal composite laminated battery cell according to claim 5 or 6, wherein: The width of the pressing portion (152) on the side where the first side edge (132) is located is D1, 4mm≤D1≤10mm; And / or, the width of the pressing portion (152) on the side where the second side edge (134) is located is D2, 4mm≤D2≤10mm.

8. The thermal composite laminated battery cell according to any one of claims 5 to 7, wherein: The width of the pressing portion (152) on the side where the bottom edge (133) is located is the same as the width of the pressing portion (152) on the side where the top edge (135) is located.

9. The thermal composite laminated battery core according to any one of claims 5 to 8, wherein: The width of the pressing portion (152) on the side where the bottom edge (133) is located is D3, 2mm≤D3≤5mm; And / or, the width of the pressing portion (152) on the side where the top edge (135) is located is D4, 2mm≤D3≤5mm.

10. The thermal composite laminated battery cell according to any one of claims 3 to 9, wherein: The distance between the side of the first pole piece (130) where the first pole tab (131) is not provided and the pressing portion (152) on the side where the first pole piece (130) is located is L, wherein 1mm≤L≤3mm.

11. The thermal composite laminated battery cell according to any one of claims 3 to 10, wherein: The first diaphragm (110) and the second diaphragm (120) are thermally composite-connected at the position of the pressing portion (152).

12. The thermal composite laminated battery core according to any one of claims 3 to 10, wherein: The first diaphragm (110) and the second diaphragm are thermally composite-connected to the second pole piece on their sides.

13. The thermal composite laminated battery core according to any one of claims 3 to 10, wherein: Adjacent first pole pieces (130) share the pressing portion (152) therebetween.

14. The thermal composite laminated battery cell according to claim 13, wherein: An incompletely cut structure (160) is provided on the pressing portion (152) between adjacent first pole pieces (130), and the composite monomer (100) is folded along the incompletely cut structure (160).

15. The thermal composite laminated battery cell according to claim 14, wherein: The incompletely cut structure (160) comprises a plurality of through holes (161) penetrating the pressing portion (152), and the plurality of through holes (161) are arranged at intervals along the width direction of the composite monomer (100).

16. The thermal composite laminated battery cell according to claim 15, wherein: The intervals between adjacent through holes (161) are the same.

17. The thermal composite laminated battery core according to claim 15 or 16, wherein: The through hole (161) is in the shape of a circle, a rectangle, an ellipse, a hexagon or an octagon.

18. The thermal composite laminated battery core according to any one of claims 15 to 17, wherein: The interval between adjacent through holes (161) is S1, wherein 5 mm ≤ S1 ≤ 20 mm.

19. The thermal composite laminated battery core according to any one of claims 15 to 18, wherein: The through hole (161) has a first size L1 and a second size W1, wherein the first size is the distance between two parallel planes that virtually abut the hole walls on both sides of the through hole (161), and the second size is the distance between two parallel planes that virtually abut the hole walls at both ends of the through hole (161), 1mm≤L1≤20mm, and / or, 1mm≤W1≤2mm.

20. The thermal composite laminated battery core according to any one of claims 1 to 19, wherein: The first pole piece (130) is a negative pole piece, and the second pole piece (140) is a positive pole piece; Alternatively, the first pole piece (130) is a positive pole piece, and the second pole piece (140) is a negative pole piece.

21. The thermal composite laminated battery cell according to claim 20, wherein: The projection of the positive electrode sheet in the thickness direction falls into the plane area where the negative electrode sheet is located.

22. A battery comprising the thermal composite laminated battery cell according to any one of claims 1 to 21.

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