WO2023098461A1 - Separator, battery cell, battery module, battery, and electric device - Google Patents

Abstract

Provided in the present application are a separator, a battery cell, a battery module, a battery, and an electric device. The separator (10) comprises first separator portions (11) and second separator portions (12) which are alternately arranged, wherein the first separator portion (11) has a first ceramic layer (110), the first ceramic layer (110) has a plurality of first portions (111) corresponding to the periphery of a first electrode plate (20), and the plurality of first portions (111) are connected to each other in any combination to surround the first electrode plate (20) along the periphery of the first electrode plate (20); and the second separator portion (12) has a second ceramic layer (120), the second ceramic layer (120) has a plurality of second portions (121) corresponding to the periphery of a second electrode plate (30), and the plurality of second portions (121) are connected to each other in any combination to surround the second electrode plate (30) along the periphery of the second electrode plate (30).

Description

Separators, battery cells, battery modules, batteries and consumers

This application claims the priority of the Chinese patent application with the application number 202111466802.8 submitted to the China Patent Office on December 01, 2021, and the title of the invention is "diaphragm, battery, battery module, battery pack and electrical device", the entire content of which is passed References are incorporated in this application.

technical field

The present application relates to the technical field of batteries, in particular to diaphragms, battery cells, battery modules, batteries and electrical devices.

Background technique

In recent years, with the continuous development of lithium-ion battery technology, lithium-ion batteries have been widely used in energy storage power systems such as water power, fire power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment , aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their safety performance and so on.

For laminated lithium-ion batteries, the pole pieces are obtained by cutting, and the positive pole pieces and the negative pole pieces are alternately stacked through a separator. Therefore, in the process of manufacturing and transporting laminated lithium-ion batteries, the pole pieces are easily dislocated, resulting in the risk of lithium precipitation on the side where the positive pole piece exceeds the negative pole piece. The tab and the negative pole tab may come into contact, causing a short circuit. In addition, when the pole piece is cut in the process of manufacturing the laminated lithium-ion battery, it is easy to produce burrs on the cut surface of the pole piece (especially the positive pole piece), and the burr may pierce the separator, thereby Cause a short circuit and affect the safety performance of the battery.

application content

The purpose of the present application is to provide a diaphragm, a battery cell, a battery module, a battery and an electrical device, which can prevent dislocation of pole pieces, prevent short circuits caused by burrs, and improve the safety performance of batteries with a simple structure and without increasing the size.

In order to achieve the above purpose, the embodiments of the present application provide a separator, a battery cell, a battery module, a battery, and an electrical device.

The first aspect of the present application provides a diaphragm, which includes alternately arranged first diaphragm parts and second diaphragm parts. In the laminated battery, the first diaphragm part and the second diaphragm part overlap in the first direction, and the bottom surface of the first pole piece and the bottom surface of the second pole piece are respectively arranged on the first diaphragm part and the above-mentioned second diaphragm part; the above-mentioned first diaphragm part has a first ceramic layer, and the above-mentioned first ceramic layer has a plurality of first parts corresponding to the periphery of the above-mentioned first pole piece, and a plurality of the above-mentioned first parts are connected by any one of them surround the first pole piece along the periphery of the first pole piece; the second diaphragm part has a second ceramic layer, and the second ceramic layer has a plurality of second parts corresponding to the periphery of the second pole piece A plurality of the second portions surround the second pole piece along the periphery of the second pole piece in such a manner that any one of them is connected.

By providing a plurality of first parts corresponding to the periphery of the first pole piece in the first diaphragm part of the diaphragm where the first pole piece can be provided, the plurality of first parts are surrounded along the periphery of the first pole piece in a manner that any of them is connected. The first pole piece, and a plurality of second parts corresponding to the periphery of the second pole piece are provided on the second diaphragm part of the diaphragm where the second pole piece can be arranged, and the plurality of second parts are connected along the The periphery of the second pole piece surrounds the second pole piece, thus, the ceramic layer can be used to limit the first pole piece and the second pole piece, preventing the assembly of the first pole piece, the second pole piece and the diaphragm In the laminated battery, the first pole piece and the second pole piece are misaligned. Therefore, lithium deposition or short circuit caused by dislocation between the first pole piece and the second pole piece can be prevented, and the safety performance of the battery can be improved. Moreover, since the first ceramic layer and the second ceramic layer are arranged on the diaphragm, no additional space is required for arrangement, and the original structure is not affected, so the structure is simple and does not increase the size, and does not reduce the energy density of the battery.

In addition, since any of the plurality of first parts provided on the first ceramic layer of the diaphragm is connected, that is, the plurality of first parts may be connected to each other, not connected to each other, or some of the first parts are connected and the remaining first parts are not connected, so , it is possible to reduce the consumption of materials for manufacturing the ceramic layer as much as possible, and reduce the cost. Likewise, since any of the plurality of second parts provided on the second ceramic layer of the diaphragm is connected, that is, the plurality of second parts may be connected to each other, not connected to each other, or some of the second parts are connected and the remaining second parts are connected to each other. Parts are not connected, therefore, the length of the ceramic layer along the periphery of the pole piece can be shortened as much as possible, the amount of materials used for manufacturing the ceramic layer can be reduced, and the cost can be reduced.

In some embodiments, the above-mentioned first pole piece and the above-mentioned second pole piece are in the shape of a cuboid; the above-mentioned first ceramic layer has four first parts corresponding to the four sides of the above-mentioned first pole piece, and the four above-mentioned first parts and The four sides of the first pole piece are respectively, when viewed from the first direction, the length of the first part along the side of the corresponding first pole piece is not greater than the length of the side surface, and the second ceramic layer has the same shape as the second ceramic layer. The four second parts corresponding to the four sides of the pole piece, the four above-mentioned second parts are respectively parallel to the four sides of the above-mentioned second pole piece, and when viewed from the above-mentioned first direction, the above-mentioned second part is along the corresponding above-mentioned second The length of the side of the pole piece is not greater than the length of the side.

The first pole piece and the second pole piece are in the shape of a cuboid, and their peripheral edges respectively have four sides, and these sides are all cut surfaces. By setting four first parts of the first ceramic layer corresponding to the four sides of the first pole piece, and setting four second parts of the second ceramic layer corresponding to the four sides of the second pole piece, it is possible to The 4 cut surfaces of the first pole piece, that is, the 4 sides, and the 4 cut surfaces of the second pole piece, that is, the 4 sides are respectively limited by the first part of the first ceramic layer and the second part of the second ceramic layer. Thereby, it is possible to prevent misalignment between the first pole piece and the second pole piece in a laminated battery assembled by assembling the first pole piece, the second pole piece, and the separator. Therefore, lithium deposition or short circuit caused by dislocation between the first pole piece and the second pole piece can be prevented, and the safety performance of the battery can be improved.

In some embodiments, the above-mentioned first pole piece is formed by laminating the first electrode active material layer and the first current collector. When the above-mentioned first pole piece is arranged on the above-mentioned first separator part, The stacking direction of the first current collector is the above-mentioned first direction, and the length of the above-mentioned first part along the side of the corresponding first pole piece is equal to the length of the side when viewed from the above-mentioned first direction, and the above-mentioned first ceramic layer is in the above-mentioned first The height in the direction is greater than the height from the bottom surface of the first pole piece to the surface of the first current collector away from the bottom surface in the first direction, and is not greater than the height of the first pole piece in the first direction .

Since the current collector of the positive electrode sheet is made of metal foil (usually aluminum foil), when cutting along the stacking direction, the positive current collector is prone to burrs. Therefore, by arranging the first ceramic layer on the first diaphragm portion of the first pole piece as the positive pole piece, and making the first ceramic layer look along the side of the corresponding first pole piece when viewed from the first direction The length of the side is equal to the length of the side, and the height of the first ceramic layer in the first direction is greater than the height from the bottom surface of the first pole piece to the surface of the first current collector away from the bottom surface in the first direction, and does not greater than the height of the first pole piece in the first direction, thus, in addition to using the first ceramic layer to restrict the first pole piece to prevent the dislocation of the first pole piece and the second pole piece, it can also be shielded (wrapped) to form Burrs on the 4 sides of the first pole piece. Therefore, while preventing dislocation, it is possible to prevent the burrs from piercing through the separator, thereby preventing a short circuit caused by the burrs, and further improving the safety performance of the battery.

In some embodiments, the second pole piece is formed by laminating the second electrode active material layer and the second current collector. When the second pole piece is arranged on the second diaphragm part, the second electrode active material layer The lamination direction of the second current collector is the first direction, and the length of the second part along the side of the corresponding second pole piece is equal to the length of the side when viewed from the first direction, and the second ceramic layer is in the The height in the first direction is greater than the height from the bottom surface of the second pole piece to the surface of the second current collector away from the bottom surface in the first direction, and is not greater than the height of the second pole piece in the first direction. upward height.

Since the current collector of the negative electrode sheet is made of metal foil (usually copper foil), when cutting along the stacking direction, the negative electrode current collector is not as easy to generate burrs as the positive electrode sheet, but there is also the possibility of burrs. Therefore, by arranging the second ceramic layer on the second diaphragm part of the second pole piece as the negative pole piece, and making the second ceramic layer look from the first direction, the second part is along the corresponding second pole piece. The length of the side is equal to the length of the side, and the height of the second ceramic layer in the first direction is greater than the height from the bottom surface of the second pole piece to the surface of the second current collector away from the bottom surface in the first direction, and Not greater than the height of the second pole piece in the first direction, thus, in addition to using the second ceramic layer to restrict the second pole piece to prevent the dislocation of the first pole piece and the second pole piece, it can also cover (wrap) Burrs formed on the 4 sides of the second pole piece. Therefore, while preventing dislocation, it is possible to prevent the burrs from piercing through the separator, thereby preventing a short circuit caused by the burrs, and further improving the safety performance of the battery.

In some embodiments, when viewed from the first direction, there is a space between the first part and the side of the corresponding first pole piece, and there is a space between the second part and the side of the corresponding second pole piece. .

By making the first part spaced from the side of the corresponding first pole piece, and making the second part spaced from the side surface of the corresponding second pole piece, it is possible to prevent the first pole piece and the second pole piece from being caused by manufacturing errors or the like. If the size of the dipole sheet is larger than the size of the surrounding area of the first ceramic layer and the second ceramic layer and cannot be assembled to the diaphragm, the qualified rate of the product can be improved. In addition, it can prevent the first pole piece and the second pole piece from being damaged due to the compression of the first ceramic layer and the second ceramic layer due to thermal expansion and contraction caused by temperature changes during transportation or use, further improving Battery safety performance.

In some embodiments, the first pole piece has a first tab formed by extending the first current collector from one side of the first pole piece to the outside, and the first pole piece is arranged on the first pole piece. In the diaphragm part, the first ceramic layer is not in contact with the first tab, and the second pole piece has a second tab formed by extending the second current collector from one side surface of the second pole piece to the outside. When the second pole piece is disposed on the second diaphragm part, the second ceramic layer is not in contact with the second tab.

By making the first ceramic layer and the second ceramic layer not in contact with the first tab and the second tab respectively, it is possible to prevent the first ceramic layer and the second ceramic layer from being squeezed and damaging the first tab and the second tab. situation, further improving the safety performance of the battery.

In some embodiments, the ceramic slurry for making the first ceramic layer and the second ceramic layer is the same. The above-mentioned ceramic slurry contains a ceramic material, a binder, a thickener, a dispersant and a defoamer. The proportion of the above-mentioned ceramic material is 20-70wt%.

Thus, the first ceramic layer and the second ceramic layer are made by using a ceramic slurry comprising ceramic materials, binders, thickeners, dispersants and defoamers, and the ceramic materials account for 20 to 70 wt%, so the second ceramic layer can be guaranteed The stability, insulation and adhesion of the first ceramic layer and the second ceramic layer, and neither too little ceramic material and insufficient stability and insulation, nor too much ceramic material and insufficient adhesion will cause the insulating layer fall off.

In some embodiments, the above-mentioned ceramic material is one of hydrated alumina, magnesia, silicon carbide and silicon nitride, and may be hydrated alumina. The binder is one or a combination of polyacrylate, methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate, and the thickener is carboxymethyl cellulose One of sodium, carboxymethyl cellulose, methyl cellulose and sodium polyacrylate, the dispersant is one or a combination of polyvinyl alcohol, polyacrylamide and polyvinyl pyrrolidone, and the defoamer is positive One or a combination of butanol and ethanol.

Therefore, the ceramic materials, binders, thickeners, dispersants and defoamers use the above cheap and easily available materials, which can reduce manufacturing costs and are beneficial to industrial production.

In some embodiments, the base film of the above separator is a base film made of PP, a base film made of PE, and a base film made of PP or PE with ceramic coating on one or both sides. A sort of.

Therefore, the base film of the diaphragm adopts the above-mentioned cheap and easy-to-obtain material, which can reduce the manufacturing cost and is beneficial to industrial production.

The second aspect of the present application provides a battery cell, which includes a first pole piece, a second pole piece, and the separator of the first aspect, wherein the first pole piece and the second pole piece are aligned in the first direction Alternately stacked, the diaphragms are sandwiched between the first pole piece and the second pole piece.

A third aspect of the present application provides a battery module, which includes the above-mentioned battery cell of the second aspect.

A fourth aspect of the present application provides a battery, which includes the battery cell of the second aspect above and/or the battery module of the third aspect above.

A fifth aspect of the present application provides an electric device, which includes at least one selected from the battery cell of the second aspect above, the battery module of the third aspect above, and the battery of the fourth aspect above.

The present application provides a diaphragm, a battery cell, a battery module, a battery and an electrical device, which can prevent dislocation of pole pieces, prevent short circuits caused by burrs, and improve the safety performance of the battery with a simple structure and without increasing the size.

Description of drawings

Figure 1 is a schematic diagram of the membrane of the present application.

Fig. 2 is a front view of the laminated battery of the present application.

3A is a cross-sectional view of the laminated battery according to the first embodiment of the present application along line A-A of FIG. 2 .

3B is a cross-sectional view of the laminated battery according to the first embodiment of the present application along line B-B of FIG. 2 .

FIG. 3C is a cross-sectional view of the laminated battery in a modified form of the first embodiment of the present application along line A-A of FIG. 2 .

3D is a cross-sectional view of the laminated battery in a modification of the first embodiment of the present application along line B-B of FIG. 2 .

4A is a cross-sectional view of a laminated battery according to a second embodiment of the present application along line A-A of FIG. 2 .

4B is a cross-sectional view of the laminated battery according to the second embodiment of the present application along line B-B of FIG. 2 .

5A is a composite view of cross-sectional views along lines A-A and B-B of FIG. 2 of a laminated battery according to a third embodiment of the present application.

5B is a composite view of cross-sectional views taken along line A-A and line B-B in FIG. 2 of a laminated battery in a modified form of the third embodiment of the present application.

FIG. 6 is a partial perspective view when the first pole piece in FIG. 5A is disposed on the first diaphragm part of the diaphragm.

Fig. 7 is a partial perspective view after removing the first ceramic layer in Fig. 6 .

8A is a combined view of cross-sectional views along lines A-A and line B-B of FIG. 2 of a laminated battery according to a fourth embodiment of the present application.

8B is a combined view of cross-sectional views along lines A-A and line B-B in FIG. 2 of a laminated battery in a modified form of the fourth embodiment of the present application.

FIG. 9 is a partial perspective view when the second pole piece in FIG. 8A is disposed on the second diaphragm part of the diaphragm.

Fig. 10 is a partial perspective view after removing the second ceramic layer in Fig. 9 .

FIG. 11 is a schematic diagram of an electrical device according to an embodiment of the present application.

Explanation of reference signs

1. Laminated battery (battery cell); 10. Diaphragm; 11. First diaphragm part; 110. First ceramic layer; 111. First part; 12. Second diaphragm part; 120. Second ceramic layer; 121 , the second part; 20, the first pole piece; 21, the first tab; 22, the first current collector; 23, the first electrode active material layer; 20a, the bottom surface; 20b, the side; 30, the second pole piece; 31. The second tab; 32. The second current collector; 33. The second electrode active material layer; 30a, the bottom surface; 30b, the side surface.

Detailed ways

Hereinafter, embodiments of the positive electrode sheet and the battery of the present application will be specifically disclosed in detail with reference to the drawings as appropriate. However, unnecessary detailed description may be omitted. For example, detailed descriptions of well-known items and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following descriptions are provided for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.

The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and an upper limit define the boundary of a particular range. Ranges defined in this manner may be inclusive or exclusive and may be combined arbitrarily, ie any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2~4 and 2~5. In the present application, unless otherwise stated, the numerical range "a~b" represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values. In addition, when expressing that a certain parameter is an integer ≥ 2, it is equivalent to disclosing that the parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

If there is no special description, all the implementation modes and optional implementation modes of the present application can be combined with each other to form new technical solutions.

If there is no special description, all the technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

If there is no special instruction, all the steps of the present application can be performed sequentially, or randomly, or sequentially. For example, the above method includes steps (a) and (b), which means that the above method may include steps (a) and (b) performed in sequence, and may also include steps (b) and (a) performed in sequence. For example, mentioning that the above method may also include step (c), it means that step (c) may be added to the above method in any order, for example, the above method may include steps (a), (b) and (c), and may also include the step (a), (c) and (b), may also include steps (c), (a) and (b) and the like.

If there is no special description, the "comprising" and "comprising" mentioned in this application mean open or closed. For example, the above-mentioned "comprising" and "comprising" may mean that other components not listed may also be included or included, or only listed components may be included or included.

In this application, the term "or" is inclusive unless otherwise stated. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied by either of the following: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists) ; or both A and B are true (or exist).

The inventor noticed that for the stacked lithium-ion battery, the pole pieces are obtained by cutting, and the positive pole pieces and the negative pole pieces are alternately stacked through the diaphragm. Therefore, in the process of manufacturing and transporting laminated lithium-ion batteries, the pole pieces are easily dislocated, resulting in the risk of lithium precipitation on the side where the positive pole piece exceeds the negative pole piece. The tab and the negative pole tab may come into contact, causing a short circuit. In addition, when cutting the pole pieces in the process of manufacturing laminated lithium-ion batteries, it is easy to generate burrs on the cut surface of the positive pole piece, which may pierce the separator, causing a short circuit and affecting the battery life. safety performance.

In some cases, the dislocation of the pole piece is prevented by setting some shielding parts separate from the pole piece and the diaphragm, but due to the large size of the shielding part, such a design will increase the size of the battery, thereby causing a loss of energy density. Affect the infiltration of electrolyte.

Therefore, the first aspect of the present application provides a diaphragm, which includes alternately arranged first diaphragm parts and second diaphragm parts. In a laminated battery with pole pieces, the first diaphragm part and the second diaphragm part overlap in the first direction, and the bottom surface of the first pole piece and the bottom surface of the second pole piece are respectively arranged on the first pole piece. A diaphragm part and the second diaphragm part, the first diaphragm part has a first ceramic layer, the first ceramic layer has a plurality of first parts corresponding to the periphery of the first pole piece, and any of the plurality of first parts is Surrounding the first pole piece along the periphery of the first pole piece in such a way that they are connected together, the second diaphragm part has a second ceramic layer, and the second ceramic layer has a plurality of first pole pieces corresponding to the periphery of the second pole piece. Two parts, wherein any one of the plurality of second parts is connected to surround the second pole piece along the periphery of the second pole piece.

By providing a plurality of first parts corresponding to the periphery of the first pole piece in the first diaphragm part of the diaphragm where the first pole piece can be provided, the plurality of first parts are surrounded along the periphery of the first pole piece in a manner that any of them is connected. The first pole piece, and a plurality of second parts corresponding to the periphery of the second pole piece are provided on the second diaphragm part of the diaphragm where the second pole piece can be arranged, and the plurality of second parts are connected along the The periphery of the second pole piece surrounds the second pole piece, thus, the ceramic layer can be used to limit the first pole piece and the second pole piece, preventing the assembly of the first pole piece, the second pole piece and the diaphragm In the laminated battery, the first pole piece and the second pole piece are misaligned. Therefore, lithium deposition or short circuit caused by dislocation between the first pole piece and the second pole piece can be prevented, and the safety performance of the battery can be improved. Moreover, since the first ceramic layer and the second ceramic layer are arranged on the diaphragm, no additional space is required for arrangement, and the original structure is not affected, so the structure is simple and does not increase the size, and at the same time does not reduce the energy density of the battery.

In addition, since any of the plurality of first parts provided on the first ceramic layer of the diaphragm is connected, that is, the plurality of first parts may be connected to each other, not connected to each other, or some of the first parts are connected and the remaining first parts are not connected, so , it is possible to reduce the consumption of materials for manufacturing the ceramic layer as much as possible, and reduce the cost. Likewise, since any of the plurality of second parts provided on the second ceramic layer of the diaphragm is connected, that is, the plurality of second parts may be connected to each other, not connected to each other, or some of the second parts are connected and the remaining second parts are connected to each other. Parts are not connected, therefore, the amount of materials used to manufacture the ceramic layer can be reduced as much as possible, and the cost can be reduced.

The second aspect of the present application provides a battery cell, which includes a first pole piece, a second pole piece, and the separator of the first aspect, wherein the first pole piece and the second pole piece are aligned in the first direction Alternately stacked, the diaphragms are sandwiched between the first pole piece and the second pole piece.

A third aspect of the present application provides a battery module, which includes the above-mentioned battery cell of the second aspect.

A fourth aspect of the present application provides a battery, which includes the battery cell of the second aspect above and/or the battery module of the third aspect above.

A fifth aspect of the present application provides an electric device, which includes at least one selected from the battery cell of the second aspect above, the battery module of the third aspect above, and the battery of the fourth aspect above.

Hereinafter, the present application will be specifically described with reference to the drawings.

FIG. 1 is a schematic diagram of a membrane 10 of the present application. As shown in FIG. 1 , the separator 10 is in a state of being assembled in a laminated battery, and is folded in a zigzag shape. The diaphragm 10 includes first diaphragm parts 11 and second diaphragm parts 12 arranged alternately.

FIG. 2 is a front view of the laminated battery 1 of the present application. When the separator 10 is arranged in the laminated battery 1 having the first pole piece 20 and the second pole piece 30 stacked alternately along the first direction Z, as shown in FIG. 2 , the first diaphragm part 11 and the second diaphragm part 12 overlap in the first direction Z, the bottom surface 20a of the first pole piece 20 is arranged on the first diaphragm part 11 , and the bottom surface 30a of the second pole piece 30 is arranged on the second diaphragm part 12 . The diaphragm 10 in FIG. 1 and FIG. 2 is a Z-folded continuous diaphragm, but the diaphragm 10 may also be a diaphragm composed of a first diaphragm part 11 and a second diaphragm part 12 that are separated.

3A is a cross-sectional view of the laminated battery 1 according to the first embodiment of the present application along line A-A of FIG. 2 , showing a plan view of the first pole piece 20 from the first direction. As shown in FIG. 3A , the first diaphragm portion 11 has a first ceramic layer 110 , and the first ceramic layer 110 has a plurality of first portions 111 (three in FIG. 3 ) corresponding to the periphery of the first pole piece 20 . Optionally, the first ceramic layer 110 corresponding to one first pole piece 20 has at least three first portions 111 to surround the first pole piece 20 . Optionally, more than one first portion 111 is provided on at least any three sides 20 b of the first pole piece 20 .

In Fig. 3A, a plurality (three) of first portions 111 surround the first pole piece 20 along the periphery of the first pole piece 20 and are not connected to each other. FIG. 3C is a cross-sectional view of the laminated battery 1 in a modified form of the first embodiment of the present application along line A-A of FIG. 2 . As shown in FIG. 3C , two first portions 111 of the three first portions 111 are connected at one corner of the periphery of the first pole piece 20 . Optionally, although not shown, the four first parts 111 in FIG. 4A described later surround the first pole piece 20 along the periphery of the first pole piece 20 in such a manner that any of them are connected. Optionally, as shown in FIG. 5B described later, a plurality (four) of first parts 111 surround the first pole piece 20 along the periphery of the first pole piece 20 and are connected to each other. That is, the plurality of first portions 111 surrounds the first pole piece 20 along the periphery of the first pole piece 20 in such a manner that any one of them is connected.

3B is a cross-sectional view of the laminated battery 1 according to the first embodiment of the present application along the line B-B in FIG. 2 , showing a plan view of the second pole piece 30 from the first direction. As shown in FIG. 3B , the second diaphragm part 12 has a second ceramic layer 120 , and the second ceramic layer 120 has a plurality of second portions 121 corresponding to the periphery of the second pole piece 30 . Optionally, the second ceramic layer 120 corresponding to one surrounding second pole piece 30 has at least three second portions 121 to surround the second pole piece 30 . One or more second portions 121 may be provided on at least any three side surfaces 30 b of the second pole piece 30 .

In FIG. 3B , a plurality (three) of second portions 121 surround the second pole piece 30 along the periphery of the second pole piece 30 and are not connected to each other. FIG. 3D is a cross-sectional view of the laminated battery 1 in a modified form of the first embodiment of the present application along line B-B in FIG. 2 . As shown in FIG. 3D , two second portions 121 among the three second portions 121 are connected at one corner of the periphery of the second pole piece 30 . Optionally, although not shown, any of the four second portions 121 in FIG. 4B described later surrounds the second pole piece 30 along its periphery so that any of them are connected. Optionally, as shown in FIG. 8B described later, a plurality of second portions 121 surround the second pole piece 30 along the periphery of the second pole piece 30 and are connected to each other. That is, the plurality of second portions 121 encloses the second pole piece 30 along the periphery of the second pole piece 30 in such a manner that any of them are connected.

By providing a plurality of first parts 111 corresponding to the periphery of the first pole piece 20 in the first diaphragm part 11 of the diaphragm 10 where the first pole piece 20 can be provided, the plurality of first parts 111 can be connected along the first pole piece 20 in any one of them. The periphery of a pole piece 20 surrounds the first pole piece 20, and a plurality of second parts 121 corresponding to the periphery of the second pole piece 30 are set on the second diaphragm part 12 of the diaphragm where the second pole piece 30 can be arranged, and a plurality of The second part 121 surrounds the second pole piece 30 along the periphery of the second pole piece 30 in such a way that any one of them is connected, thereby, the first pole piece 20 and the second pole piece 30 can be limited by the ceramic layer, It prevents misalignment of the first pole piece 20 and the second pole piece 30 in the laminated battery 1 assembled with the first pole piece 20 , the second pole piece 30 and the diaphragm. Therefore, lithium deposition or short circuit caused by dislocation between the first pole piece 20 and the second pole piece 30 can be prevented, and the safety performance of the battery can be improved. Moreover, since the first ceramic layer 110 and the second ceramic layer 120 are disposed on the diaphragm, no additional space is required for the arrangement, and the original structure is not affected, so the structure is simple and does not increase the size, and does not reduce the energy density of the battery.

In addition, since any of the plurality of first parts 111 of the first ceramic layer 110 disposed on the diaphragm 10 is connected, that is, the plurality of first parts 111 may be connected to each other, not connected to each other, or some of the first parts 111 are connected and the remaining first parts 111 are connected to each other. A part 111 is not connected, therefore, the amount of materials used to manufacture the ceramic layer can be reduced as much as possible, and the cost can be reduced. Likewise, since any of the plurality of second parts 121 of the second ceramic layer 120 of the diaphragm 10 is connected, that is, the plurality of second parts 121 may be connected to each other, not connected to each other, or some of the second parts 121 are connected. And the remaining second part 121 is not connected, therefore, the length of the ceramic layer along the periphery of the pole piece can be shortened as much as possible, the amount of materials used for manufacturing the ceramic layer can be reduced, and the cost can be reduced.

4A is a cross-sectional view of the laminated battery 1 according to the second embodiment of the present application along the line A-A of FIG. 2 , showing a plan view of the first pole piece 20 from the first direction. 4B is a cross-sectional view of the laminated battery 1 according to the second embodiment of the present application along the line B-B in FIG. 2 , showing a plan view of the second pole piece 30 from the first direction. In some embodiments, as shown in FIG. 2 , FIG. 4A and FIG. 4B , the first pole piece 20 and the second pole piece 30 are in the shape of a cuboid.

As shown in FIG. 4A, the first ceramic layer 110 has four first portions 111 corresponding to the four sides 20b of the first pole piece 20, and the four first portions 111 are respectively parallel to the four sides 20b of the first pole piece 20, When viewed from the first direction Z, the length of the first portion 111 along the side 20b of the corresponding first pole piece 20 is not greater than the length of the side 20b. As shown in Figure 4B, the second ceramic layer 120 has four second parts 121 corresponding to the four side faces 30b of the second pole piece 30, and the four second parts 121 are respectively connected to the four side faces 30b of the second pole piece 30. Parallel, the length of the second portion 121 along the side 30b of the corresponding second pole piece 30 is not greater than the length of the side 30b when viewed from the first direction Z. The four first parts 111 shown in FIG. 4A are not connected to each other, but it is also possible that any one of the four first parts 111 is connected at the corner of the periphery of the first pole piece 20 (where the two sides 20b are connected). The four second parts 121 shown in FIG. 4B are not connected to each other, but it may also be that any one of the four second parts 121 is connected at the corner of the periphery of the second pole piece 30 (where the two sides 30b are connected) .

The peripheries of the rectangular parallelepiped first pole piece 20 and the second pole piece 30 respectively have four side surfaces 20b, 30b, and these side surfaces 20b, 30b are all cut surfaces. By setting the four first parts 111 of the first ceramic layer 110 corresponding to the four sides 20b of the first pole piece 20, and corresponding to the four sides 20b of the second pole piece 30, four parts of the second ceramic layer 120 are provided. The second part 121 can use the four cutting surfaces of the first pole piece 20, that is, the four sides 20b and the four cutting surfaces of the second pole piece 30, that is, the four sides 30b, respectively with the first ceramic layer 110. A portion 111 is bounded by a second portion 121 of the second ceramic layer 120 . Thus, it is possible to prevent misalignment between the first pole piece 20 and the second pole piece 30 in the laminated battery 1 assembled with the first pole piece 20 , the second pole piece 30 and the separator. Therefore, lithium deposition or short circuit caused by dislocation between the first pole piece 20 and the second pole piece 30 can be prevented, and the safety performance of the battery can be improved.

5A is a combined view of the cross-sectional views of the laminated battery 1 of the third embodiment of the present application along the A-A line and the B-B line of FIG. 2 , showing a plan view of the first pole piece 20 and the second pole piece from the first direction. 30 graphs. FIG. 5B is a combined view of the cross-sectional views of the laminated battery 1 along the lines A-A and B-B in FIG. 2 , which is a modified form of the third embodiment of the present application. FIG. 6 is a partial perspective view when the first pole piece 20 in FIG. 5A is disposed on the first diaphragm part 11 of the diaphragm 10 . FIG. 7 is a partial perspective view after removing the first ceramic layer 110 in FIG. 6 .

In some embodiments, as shown in FIG. 7 , the first pole piece 20 is formed by stacking a first electrode active material layer 23 and a first current collector 22 . As shown in FIG. 5A and FIG. 6, when the first pole piece 20 is arranged on the first diaphragm part 11, the stacking direction of the first electrode active material layer 23 and the first current collector 22 is the first direction Z, and the direction from the first direction Z When viewed, the length of the first portion 111 along the side 20b of the corresponding first pole piece 20 is equal to the length of the side 20b. Moreover, the height H1 of the first ceramic layer 110 in the first direction Z is greater than the height H2 from the bottom surface 20a of the first pole piece 20 to the surface of the first current collector 22 away from the bottom surface 20a in the first direction Z, and Not greater than the height H3 of the first pole piece 20 in the first direction Z.

In addition, as shown in FIG. 5A , the second ceramic layer 120 surrounding the second pole piece 30 is the same as that in FIG. 4B .

In addition, as shown in FIG. 7 , the first electrode active material layer 23 in the first pole piece 20 is two layers, sandwiching the first current collector 22 . However, the first electrode active material layer 23 may also be one layer.

In FIG. 5A , when viewed from the first direction Z, the length of the four first parts 111 along the side 20b of the corresponding first pole piece 20 is equal to the length of the side 20b, that is, the four first parts 111 are not connected to each other. However, due to the extremely thin thickness of the first ceramic layer 110 and considering the simplicity of the coating process, as shown in FIG. 5B , the four first parts 111 may be connected to each other at the corners of the first pole piece 20 .

Since the current collector of the positive electrode sheet is made of metal foil (usually aluminum foil), when cutting along the stacking direction, the positive current collector is prone to burrs. Therefore, by disposing the first ceramic layer 110 on the first diaphragm part 11 of the first pole piece 20 as the positive pole piece, and making the first ceramic layer 110 viewed from the first direction Z along the corresponding The length of the side 20b of the first pole piece 20 is equal to the length of the side 20b, and the height of the first ceramic layer 110 in the first direction Z is greater than that from the bottom surface 20a of the first pole piece 20 to the first current collector 22. The height of the surface away from the bottom surface 20a in the first direction Z is not greater than the height of the first pole piece 20 in the first direction Z, thus, in addition to using the first ceramic layer 110 to limit the first pole piece 20 to prevent the second In addition to the misalignment between the first pole piece 20 and the second pole piece 30 , the burrs formed on the four side surfaces 20 b of the first pole piece 20 can also be covered (wrapped). Therefore, while preventing dislocation, it is possible to prevent the burrs from piercing through the separator, thereby preventing a short circuit caused by the burrs, and further improving the safety performance of the battery.

8A is a combined view of the cross-sectional views of the laminated battery 1 of the fourth embodiment of the present application along the A-A line and the B-B line of FIG. 2 , showing a plan view of the first pole piece 20 and the second pole piece from the first direction. 30 graphs. 8B is a combined view of cross-sectional views along lines A-A and line B-B in FIG. 2 of a laminated battery in a modified form of the fourth embodiment of the present application. FIG. 9 is a partial perspective view when the second pole piece 30 in FIG. 8A is disposed on the second diaphragm part 12 of the diaphragm 10 . FIG. 10 is a partial perspective view after removing the second ceramic layer 120 in FIG. 9 .

In some embodiments, as shown in FIG. 10 , the second pole piece 30 is formed by stacking a second electrode active material layer 33 and a second current collector 32 . As shown in FIG. 8A and FIG. 9 , when the second pole piece 30 is arranged on the second diaphragm part 12, the stacking direction of the second electrode active material layer 33 and the second current collector 32 is the first direction Z, and from the first direction The length of the second part 121 along the side 30b of the corresponding second pole piece 30 when viewed from Z is equal to the length of the side 30b. Moreover, the height H4 of the second ceramic layer 120 in the first direction Z is greater than the height H5 from the bottom surface 30a of the second pole piece 30 to the surface of the second current collector 32 away from the bottom surface 30a in the first direction Z, and Not greater than the height H6 of the second pole piece 30 in the first direction Z.

In addition, as shown in FIG. 8A , the first ceramic layer 110 surrounding the first pole piece 20 is the same as that in FIG. 5A .

In addition, as shown in FIG. 10 , the second electrode active material layer 33 in the second pole piece 30 is two layers, sandwiching the second current collector 32 . However, the second electrode active material layer 33 may also be one layer.

In FIG. 8A , when viewed from the first direction Z, the length of the four second parts 121 along the side 30b of the corresponding second pole piece 30 is equal to the length of the side 30b, that is, the four second parts 121 are not connected to each other. However, due to the extremely thin thickness of the second ceramic layer 120 and considering the simplicity of the coating process, as shown in FIG. 8B , the four second parts 121 may be connected to each other at the corners of the periphery of the second pole piece 30 .

Since the current collector of the negative electrode sheet is made of metal foil (usually copper foil), when cutting along the stacking direction, the negative electrode current collector is not as prone to burrs as the positive electrode sheet, but there is also the possibility of burrs. Therefore, by disposing the second ceramic layer 120 on the second diaphragm part 12 of the second pole piece 30 as the negative electrode piece, and making the second ceramic layer 120 viewed from the first direction Z along the corresponding The length of the side 30b of the second pole piece 30 is equal to the length of the side 30b, and the height of the second ceramic layer 120 in the first direction Z is greater than that from the bottom surface 30a of the second pole piece 30 to the second current collector 32 The height of the surface away from the bottom surface 30a in the first direction Z is not greater than the height of the second pole piece 30 in the first direction Z, thus, in addition to using the second ceramic layer 120 to limit the second pole piece 30 to prevent In addition to the misalignment between the first pole piece 20 and the second pole piece 30 , burrs formed on the four side surfaces 30 b of the second pole piece 30 can be covered (wrapped). Therefore, while preventing dislocation, it is possible to prevent the burrs from piercing through the separator, thereby preventing a short circuit caused by the burrs, and further improving the safety performance of the battery.

In some embodiments, although not shown, when viewed from the first direction Z, the first part 111 is spaced from the side of the corresponding first pole piece 20, and the second part 121 is spaced from the side of the corresponding second pole piece 30. spaced between the sides.

By appropriately spacing the first portion 111 from the side of the corresponding first pole piece 20, and properly spacing the second portion 121 from the side of the corresponding second pole piece 30, it is possible to prevent the Manufacturing errors and the like lead to the fact that the size of the first pole piece 20 and the second pole piece 30 is larger than the size of the surrounding area of the first ceramic layer 110 and the second ceramic layer 120 and cannot be assembled to the diaphragm, which can improve the yield of the product. In addition, it can prevent the first pole piece 20 and the second pole piece 30 from being damaged by being pressed by the first ceramic layer 110 and the second ceramic layer 120 due to thermal expansion and contraction caused by temperature changes during transportation or use. situation, further improving the safety performance of the battery.

In some embodiments, the first pole piece 20 has a first tab 21 formed by the first current collector 22 extending from one side 20b of the first pole piece 20 to the outside, and the first pole piece 20 is arranged at the second When there is a diaphragm part 11, the first ceramic layer 110 is not in contact with the first tab 21, and the second pole piece 30 has a second current collector 32 extending from one side 30b of the second pole piece 30 to the outside. For the second pole tab 31 , when the second pole piece 30 is disposed on the second diaphragm portion 12 , the second ceramic layer 120 does not contact the second pole tab 31 .

By making the first ceramic layer 110 and the second ceramic layer 120 not in contact with the first tab 21 and the second tab 31 respectively, it is possible to prevent the first ceramic layer 110 and the second ceramic layer 120 from being squeezed and damaging the first tab. 21 and the second tab 31, further improving the safety performance of the battery. The point that the first ceramic layer 110 is not in contact with the first tab 21 and the second ceramic layer 120 is not in contact with the second tab 31 is not shown in the drawings, but as long as the first ceramic layer 110 is in contact with the first tab There is a gap between the 21 and the gap between the second ceramic layer 120 and the second tab 31 , and the gap can prevent extrusion due to deformation caused by thermal expansion and contraction.

In some embodiments, the ceramic slurry used to make the first ceramic layer 110 and the second ceramic layer 120 is the same. Ceramic slurry contains ceramic materials, binders, thickeners, dispersants and defoamers. The proportion of the ceramic material is 20-70wt%.

Thus, the first ceramic layer 110 and the second ceramic layer 120 are made by using a ceramic slurry comprising ceramic materials, binders, thickeners, dispersants and defoamers, and the ceramic materials account for 20 to 70 wt%, so it is possible to Ensure the stability, insulation and adhesiveness of the first ceramic layer 110 and the second ceramic layer 120, and neither too little ceramic material will cause insufficient stability and insulation, nor will there be too much ceramic material and adhesiveness Not enough to cause the insulation to fall off.

In some embodiments, the ceramic material is one of hydrated alumina, magnesia, silicon carbide and silicon nitride, optionally hydrated alumina. The binder is one or a combination of polyacrylate, methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2-ethyl methacrylate, and the thickener is carboxymethyl cellulose One of sodium, carboxymethyl cellulose, methyl cellulose and sodium polyacrylate, the dispersant is one or a combination of polyvinyl alcohol, polyacrylamide and polyvinyl pyrrolidone, and the defoamer is positive One or a combination of butanol and ethanol.

Therefore, the ceramic materials, binders, thickeners, dispersants and defoamers use the above cheap and easily available materials, which can reduce manufacturing costs and are beneficial to industrial production.

In some embodiments, the base film of the separator 10 is a base film made of PP or a base film made of PE.

Therefore, the base film of the diaphragm adopts the above-mentioned cheap and easy-to-obtain material, which can reduce the manufacturing cost and is beneficial to industrial production.

FIG. 2 is a schematic diagram of a battery cell (laminated battery 1 ) according to an embodiment of the present application. The battery cell (stacked battery 1) includes the first pole piece 20, the second pole piece 30 and the separator of the above-mentioned first aspect, and the first pole piece 20 and the second pole piece 30 are stacked alternately in the first direction Z , the diaphragm 10 is sandwiched between the first pole piece 20 and the second pole piece 30 .

In some embodiments, the battery cells can be assembled into a battery module, and the number of battery cells contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.

In the battery module, multiple battery cells (stacked batteries) can be arranged in sequence along the length direction of the battery module. Of course, it can also be arranged in any other manner. Further, the plurality of battery cells can be fixed by fasteners. Optionally, the battery module may further include a casing having an accommodating space, and a plurality of battery cells are accommodated in the accommodating space.

In some embodiments, the above-mentioned battery modules can also be assembled into a battery, and the number of battery modules contained in the battery can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery pack.

A battery case and a plurality of battery modules provided in the battery case may be included in the battery. The battery box includes an upper box and a lower box. The upper box can cover the lower box and form a closed space for accommodating the battery module. Multiple battery modules can be arranged in the battery box in any manner.

In addition, the present application also provides an electric device, which includes at least one of the battery cells, battery modules, or batteries provided in the present application. A battery cell, a battery module, or a battery can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device. The electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.

As the electric device, a battery cell, a battery module or a battery can be selected according to its usage requirements.

FIG. 11 is a schematic diagram of an electrical device according to an embodiment of the present application. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. In order to meet the high power and high energy density requirements of the electric device for the battery, a battery pack or a battery module can be used.

As another example, a device may be a cell phone, tablet, laptop, or the like. The device is usually required to be light and thin, and a battery can be used as a power source.

[Example]

Hereinafter, examples of the present application will be described. The embodiments described below are exemplary and are only used for explaining the present application, and should not be construed as limiting the present application. If no specific technique or condition is indicated in the examples, it shall be carried out according to the technique or condition described in the literature in this field or according to the product specification. The reagents or instruments used were not indicated by the manufacturer, and they were all commercially available conventional products.

(Example 1)

1. Preparation of the first pole piece

The first electrode active material is coated on both sides of the first current collector, and after cold pressing and cutting, the first pole piece (ie, the positive pole piece) is obtained.

2. Preparation of the Second Pole Piece

The second electrode active material is coated on both sides of the second current collector, and after cold pressing and cutting, the second electrode sheet (ie, the negative electrode sheet) is obtained.

3. Preparation of Septa

(1) Fabricate a base film made of PP.

(2) According to the position and length of the sides of the first pole piece and the second pole piece when viewed from the first direction, the length of the first ceramic layer and the second ceramic layer is set to 1 of the length of the corresponding side surface /4, and determine where to place the first ceramic layer and the second ceramic layer.

(3) While moving the diaphragm in the horizontal direction, the ceramic slurry is sprayed on the first diaphragm portion of the diaphragm using a nozzle of a spraying equipment. By moving the spray head back and forth, left and right, the ceramic slurry is sprayed correspondingly to any three sides of the first pole piece. Control the spraying time of the spraying equipment at the same position, adjust the height of the first ceramic layer in the first direction to 1/2 of the height of the first pole piece, which is lower than the bottom surface of the first current collector away from the first pole piece noodle. While spraying, it is dried in an oven at 80-120°C.

(4) While moving the diaphragm in the horizontal direction, the ceramic slurry is sprayed on the second diaphragm portion of the diaphragm using a nozzle of a spraying equipment. By moving the spray head back and forth, left and right, the ceramic slurry is sprayed correspondingly to any three sides of the second pole piece. Control the spraying time of the spraying equipment at the same position, adjust the height of the second ceramic layer in the first direction to 1/2 of the height of the second pole piece, which is lower than the bottom surface of the second current collector away from the second pole piece noodle. While spraying, it is dried in an oven at 80-120°C.

The diaphragm obtained through the above steps has a first ceramic layer formed on one side and a second ceramic layer formed on the other side, and the first ceramic layer and the second ceramic layer are distributed in a staggered manner, that is, when the first ceramic layer is located on the front side, its The opposite side of the corresponding position has no second ceramic layer.

4. Assembly

Using the assembly jig, put the cut second pole piece into the area surrounded by the second ceramic layer on the diaphragm, then fold the diaphragm in a Z shape, and put the cut first pole piece into the area surrounded by the first ceramic layer on the diaphragm area, fold the diaphragm in a Z shape again, and assemble it in the order of "diaphragm-second pole piece-diaphragm-first pole piece-diaphragm-second pole piece..." to obtain the laminated battery of Example 1.

(Example 2)

In the same manner as in Example 1, the laminate of Example 2 is obtained except that the first ceramic layer and the second ceramic layer are respectively set corresponding to all sides (four sides) of the first pole piece and the second pole piece. chip battery.

(Example 3)

The first ceramic layer or the second ceramic layer is respectively arranged corresponding to all sides (four sides) of the first pole piece and the second pole piece; when viewed from the first direction, the length of the first part of the first ceramic layer corresponds to The sides of the first pole piece are equal in length, and the height of the first portion in the first direction is higher than the surface of the first current collector away from the bottom surface of the first pole piece. Except for this, in the same manner as in Example 1, the laminated battery of Example 3 was obtained.

(Example 4)

The first ceramic layer or the second ceramic layer is respectively arranged corresponding to all sides (four sides) of the first pole piece and the second pole piece; when viewed from the first direction, the length of the first part of the first ceramic layer corresponds to The side lengths of the first pole piece are equal, and the height of the first part in the first direction is higher than the surface of the first current collector away from the bottom surface of the first pole piece; when viewed from the first direction, the first part of the second ceramic layer The length of the two parts is equal to the side length of the corresponding second pole piece, and the height of the second part in the first direction is higher than the surface of the second current collector away from the bottom surface of the second pole piece. Except for this, in the same manner as in Example 1, a laminated battery of Example 4 was obtained.

(comparative example 1)

A laminated battery of Comparative Example 1 was obtained in the same manner as in Example 1 except that the first ceramic layer and the second ceramic layer were not provided on the separator.

(comparative example 2)

In the same manner as in Example 1, the laminated battery of Comparative Example 2 was obtained, except that the first ceramic layer and the second ceramic layer were respectively arranged corresponding to any two sides of the first pole piece and the second pole piece. .

200 laminated batteries of the above-mentioned Examples 1 to 4, Comparative Example 1 and Comparative Example 2 were produced respectively. 100 laminated batteries of the above-mentioned Examples 1 to 4, Comparative Example 1 and Comparative Example 2 were selected, and an X-Ray detector was used to check whether the first pole piece and the second pole piece were misaligned. Calculate the percentage of the number of dislocated pole pieces to the total number, and record it in the column of pole piece dislocation probability in Table 1. In addition, the remaining 100 laminated batteries of the above-mentioned embodiments 1 to 4, comparative example 1 and comparative example 2 were selected, and the insulation withstand voltage test (Hi-pot test) was performed on these laminated batteries to determine Check for burrs piercing the diaphragm. Count the number of batteries that fail the insulation withstand voltage test, calculate the percentage of the total number, and record it in the column of the probability of burr piercing the separator in Table 1.

Table 1 Evaluation results of laminated batteries

Table 1 shows the evaluation results of laminated batteries. According to Table 1, when the first ceramic layer and the second ceramic layer are not provided (as in comparative example 1), the pole piece dislocation probability is the highest; when the first ceramic layer and the second ceramic layer on the diaphragm are distributed on the first pole When any two sides of the pole piece and the second pole piece (such as comparative example 2), it is inevitable that the pole piece will be displaced to the side without the ceramic layer, causing the pole piece to be dislocated; when the first ceramic layer and the second pole piece on the diaphragm When the two ceramic layers are distributed on any 3 sides of the first pole piece and the second pole piece (as in Example 1), the probability of dislocation of the pole piece is greatly reduced; when the first ceramic layer and the second ceramic layer on the diaphragm are distributed When all sides of the first pole piece and the second pole piece are 4 sides (as in embodiment 2), the probability of misalignment of the pole pieces can be reduced to a very low level.

In Example 1, Example 2, Comparative Example 1 and Comparative Example 2, the length of the first ceramic layer and the second ceramic layer is less than the length of the corresponding side, and the height is lower than the surface of the current collector away from the bottom surface of the pole piece, This has a slight effect on the probability of pole piece misalignment, but still within an appropriate range, and a large effect on the probability of a burr puncturing the diaphragm. When for the first pole piece, the first ceramic layer is distributed on its 4 sides and the length of the first ceramic layer is equal to the length of the corresponding side, and the height of the first ceramic layer is higher than the surface away from the bottom surface of the first current collector (such as In embodiment 3), it is possible to wrap the burrs on the 4 sides (i.e. the cutting surface) of the first pole piece as the positive pole piece, greatly reducing the probability of the burr piercing the diaphragm; when not only the first pole piece is set like this, but also the second Diode sheet, the second ceramic layer is distributed on its 4 sides and the length of the second ceramic layer is equal to the length of the corresponding side, the height of the second ceramic layer is higher than the surface away from the bottom surface of the second current collector (as in embodiment 4 ), further wrapping the burrs on the four sides (ie, the cut surface) of the second pole piece as the negative pole piece can greatly reduce the probability of the burr piercing the diaphragm.

Therefore, on the premise of not increasing the size of the battery and reducing the volumetric energy density of the cell, on the one hand, this application greatly reduces or even avoids the dislocation of the pole pieces of the stacked battery and the risk of lithium precipitation caused by this situation; on the other hand, Greatly reduce or even avoid the risk of internal short circuit caused by burrs piercing the separator.

It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application. In addition, without departing from the scope of the present application, various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

Claims (14)

A diaphragm characterized in that: Including alternately arranged first diaphragm parts and second diaphragm parts, when the diaphragm is arranged in a laminated battery having first pole pieces and second pole pieces stacked alternately along the first direction, the first The diaphragm part overlaps with the second diaphragm part in the first direction, and the bottom surface of the first pole piece and the bottom surface of the second pole piece are respectively arranged on the first diaphragm part and the second pole piece. Diaphragm; The first diaphragm part has a first ceramic layer, the first ceramic layer has a plurality of first parts corresponding to the periphery of the first pole piece, and the plurality of first parts are connected along any one of them. the periphery of the first pole piece surrounds the first pole piece; The second diaphragm part has a second ceramic layer, the second ceramic layer has a plurality of second parts corresponding to the periphery of the second pole piece, and the plurality of second parts are connected in any one of them The second pole piece is surrounded along the periphery of the second pole piece. The diaphragm according to claim 1, characterized in that: The first pole piece and the second pole piece are in the shape of a cuboid; The first ceramic layer has four first parts corresponding to the four sides of the first pole piece, and the four first parts are respectively parallel to the four sides of the first pole piece. The length of the first portion along the side of the corresponding first pole piece is not greater than the length of the side when viewed in the same direction; The second ceramic layer has four second parts corresponding to the four sides of the second pole piece, and the four second parts are respectively parallel to the four sides of the second pole piece. When viewed from the first direction, the length of the second portion along the side of the corresponding second pole piece is not greater than the length of the side. The diaphragm according to claim 2, characterized in that: The first pole piece is formed by stacking a first electrode active material layer and a first current collector. When the first pole piece is arranged on the first diaphragm part, the first electrode active material layer and the first electrode active material layer The stacking direction of a current collector is the first direction; When viewed from the first direction, the length of the first portion along the side of the corresponding first pole piece is equal to the length of the side; The height of the first ceramic layer in the first direction is greater than the height from the bottom surface of the first pole piece to the surface of the first current collector away from the bottom surface in the first direction, and is not greater than the height of the first pole piece in the first direction. The diaphragm according to claim 3, characterized in that: The second pole piece is formed by stacking a second electrode active material layer and a second current collector. When the second pole piece is placed on the second diaphragm part, the second electrode active material layer and the The stacking direction of the second current collector is the first direction; When viewed from the first direction, the length of the second portion along the side of the corresponding second pole piece is equal to the length of the side; The height of the second ceramic layer in the first direction is greater than the height from the bottom surface of the second pole piece to the surface of the second current collector away from the bottom surface in the first direction, and is not greater than the height of the second pole piece in the first direction. The diaphragm according to any one of claims 1 to 4, characterized in that: When viewed from the first direction, there is a space between the first part and the corresponding side of the first pole piece, and there is a space between the second part and the corresponding side of the second pole piece. The diaphragm according to any one of claims 1 to 4, characterized in that: The first pole piece has a first tab formed by extending the first current collector from one side of the first pole piece to the outside, and the first pole piece is arranged on the first diaphragm part, the first ceramic layer is not in contact with the first tab; The second pole piece has a second tab formed by extending the second current collector from one side of the second pole piece to the outside, and the second pole piece is arranged on the second diaphragm When the second ceramic layer is not in contact with the second tab. The diaphragm according to any one of claims 1 to 4, characterized in that: The ceramic slurry for making the first ceramic layer and the second ceramic layer is the same, and the ceramic slurry includes ceramic material, binder, thickener, dispersant and defoamer, and the proportion of the ceramic material is The ratio is 20 to 70 wt%. The diaphragm according to claim 7, characterized in that: The ceramic material is one of hydrated alumina, magnesium oxide, silicon carbide and silicon nitride, and the binder is polyacrylate, methyl acrylate, ethyl acrylate, 2-methyl methacrylate and 2 - one or more combinations of ethyl methacrylate, the thickener is one of sodium carboxymethyl cellulose, carboxymethyl cellulose, methyl cellulose and sodium polyacrylate, the The dispersant is one or a combination of polyvinyl alcohol, polyacrylamide and polyvinylpyrrolidone, and the defoamer is one or a combination of n-butanol and ethanol. The diaphragm according to claim 8, characterized in that: The ceramic material is hydrated alumina. The diaphragm according to any one of claims 1 to 4, characterized in that: The base film of the separator is a base film made of PP or a base film made of PE. A battery cell, characterized in that: Comprising a first pole piece, a second pole piece and the diaphragm according to any one of claims 1-10; The first pole piece and the second pole piece are alternately stacked in the first direction; The diaphragm is sandwiched between the first pole piece and the second pole piece. A battery module, characterized in that: The battery cell described in claim 11 is included. A battery characterized in that: The battery cell according to claim 11 and/or the battery module according to claim 12 are included. An electrical device, characterized in that: It includes at least one selected from the battery cell described in claim 11, the battery module described in claim 12, and the battery pack described in claim 13.

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