Electrode assembly, battery and electrochemical device

Abstract

The utility model relates to the technical field of energy storage devices, and specifically provides an electrode assembly, a battery and an electrochemical device; the utility model comprises a pole piece with a current collector and a first protective layer for preventing a pole ear from piercing the pole piece; a first groove is provided on the active material layer of the current collector, and a second groove is provided on the corresponding active material layer of the current collector in an adjacent pole piece; wherein a pole ear is embedded in the first groove, a first protective layer is embedded in the second groove, and the first groove and the second groove are arranged oppositely; the utility model prevents the burrs of the pole ear from piercing the diaphragm through the first protective layer embedded in the second groove, thereby avoiding micro short circuit of the battery cell.

Description

Technical Field

[0001] The utility model belongs to the technical field of energy storage devices, and in particular relates to an electrode assembly, a battery and an electrochemical device. Background Art

[0002] As one of the important processes in the production and manufacturing of lithium-ion batteries, welding tabs is aimed at connecting external circuits through tabs. Tabs include metal tabs that play a conductive role and tab glue attached to the metal tabs.

[0003] like Figure 1 As shown, in the electrode assembly 1', in order to prevent the burrs on the pole ear 12' from piercing the second protective layer 14' (pole ear glue) and the isolation film 11' and then damaging the pole piece 10', a first protective layer 13' is usually attached to the side opposite to the welding area of ​​the pole ear 12' on the adjacent pole piece 10'. However, the aforementioned method increases the thickness of the battery cell and reduces the mass energy density of the battery cell.

[0004] Based on this, there is an urgent need to invent an electrode assembly, a battery and an electrochemical device to solve the aforementioned technical problems. Utility Model Content

[0005] The technical problem to be solved by the utility model is how to reduce the thickness of a bare battery cell to improve the mass energy density. In view of the above problem, an electrode assembly, a battery and an electrochemical device are provided.

[0006] The technical solution of the utility model to solve the above technical problems is to provide an electrode assembly, comprising: a pole piece with a current collector and a first protective layer for preventing the pole tab from piercing the pole piece;

[0007] A first groove is formed on the active material layer of the current collector, and a second groove is formed on the corresponding active material layer of the current collector in the adjacent pole piece; wherein a pole ear is embedded in the first groove, a first protective layer is embedded in the second groove, and the first groove and the second groove are arranged opposite to each other.

[0008] Specifically, along the thickness direction of the electrode assembly, the depth of the second groove is greater than the thickness of the first protective layer, and the projection of the second groove covers the projection of the first groove;

[0009] The second groove has an escape space formed by the active material layer and the ceramic layer and for the tab to extend into.

[0010] Specifically, the second groove is formed by laser cleaning, mechanical cleaning, or foaming glue cleaning the active material layer to expose the current collector.

[0011] Specifically, the first protective layer includes a ceramic layer, a colloid layer, and a substrate layer attached between the ceramic layer and the colloid layer.

[0012] Specifically, the first protective layer includes a ceramic layer and a colloid layer.

[0013] In terms of size, the thickness of the first protective layer is between 2um and 50um; and / or the hardness W1 of the ceramic layer in the first protective layer satisfies: 80HRA≤W1≤90HRA.

[0014] More preferably, the weight of the ceramic particles in the ceramic layer accounts for 20% to 99% of the total weight of the ceramic layer.

[0015] Specifically, a second protective layer is also included, and the second protective layer covers the notch of the first groove.

[0016] In one specific embodiment, a battery is provided, comprising a packaging shell and the electrode assembly as described above, wherein the packaging shell is coated on the electrode assembly.

[0017] In one specific embodiment, an electrochemical device is provided, comprising the battery as described above.

[0018] The beneficial effect of the utility model is that the first protective layer embedded in the second groove prevents the burrs of the pole ear from piercing the diaphragm, thereby avoiding a micro short circuit in the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the implementation modes of the present invention, the drawings required for use in the description of the implementation modes will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic diagram of the structure of an existing electrode assembly;

[0021] 1'-electrode assembly;

[0022] 10'-pole piece; 11'-isolating film; 12'-pole ear; 13'-first protective layer; 14'-second protective layer.

[0023] Figure 2 It is a structural schematic diagram of the electrode assembly of the utility model;

[0024] Figure 3 This utility model Figure 2 One of the implementation modes of the first protective layer;

[0025] Figure 4 This utility model Figure 2 The second implementation method of the first protective layer.

[0026] Reference numerals:

[0027] 1-Electrode assembly;

[0028] 10-pole piece; 100-current collector; 101-active material layer; 1010-first groove; 1011-second groove; 1012-avoidance space;

[0029] 11 - isolation film; 12 - pole ear; 13 - first protective layer; 130 - ceramic layer; 131 - colloid layer; 132 - substrate layer; 14 - second protective layer. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the implementation of the utility model clearer, the technical solution in the implementation of the utility model will be clearly and completely described below in conjunction with the drawings in the implementation of the utility model. Obviously, the described implementation is a part of the implementation of the utility model, not all of the implementations. Based on the implementation of the utility model, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] Implementation Method 1

[0032] refer to Figure 2 The utility model provides an electrode assembly 1. It should be noted that the electrode assembly 1 can be manufactured, licensed and sold separately. The electrode assembly 1 includes a pole piece 10 having a current collector 100 (the pole piece 10 here can be an anode pole piece or a cathode pole piece) and a first protective layer 13. Specifically, a first groove 1010 is provided on the active material layer 101 of the current collector 100 (refer to the following for details). It should be noted that both sides of the current collector 100 are coated with an active material layer 101, which means that the first groove 1010 is provided on the active material layer 101 on one side of the current collector 100 (the same below). And the corresponding active material layer 101 of the current collector 100 in the adjacent pole piece 10 is provided with a second groove 1011, and the active material layer 101 here is the active material layer 101 close to the side of the first groove 1010. In order to avoid the increase of the thickness of the battery cell due to the lead-out tabs 12 from the positive and negative current collectors 100, the tabs 12 are embedded in the first grooves 1010. In contrast, the second grooves 1011 are embedded with the first protective layer 13 for preventing the tabs 12 from piercing the pole pieces 10. Obviously, the first grooves 1010 and the second grooves 1011 are arranged opposite to each other.

[0033] Specifically, in order to adapt to the shape of the pole ear 12, the first groove 1010 and the second groove 1011 can both be rectangular grooves. Of course, in other specific embodiments, the first groove 1010 and the second groove 1011 can also be other shapes. And in order to achieve a better protection effect, that is, when the pole ear 12 pierces the second protective layer 14 and the isolation film 11 in turn and gradually approaches the adjacent pole piece 10, due to the burrs on the pole ear 12, in order to prevent the pole ear 12 from piercing the pole piece 10 and causing a micro short circuit in the battery cell, the first protective layer 13 needs to completely cover the pole ear 12. In other words, continue to refer to Figure 2 The width of the first protection layer 13 is greater than the width of the tab 12 . Correspondingly, the width of the second groove 1011 is greater than the width of the first groove 1010 .

[0034] Implementation Method 2

[0035] The difference between this embodiment and embodiment 1 is that: in order to further prevent the pole ear 12 from piercing the pole piece 10, along the thickness direction of the electrode assembly 1, the depth value of the second groove 1011 is greater than the thickness value of the first protective layer 13, that is, the first protective layer 13 does not fill the second groove 1011; at the same time, referring to the above, the width value of the second groove 1011 is greater than the width value of the second groove 1011, in other words, the projection of the second groove 1011 covers the projection of the first groove 1010. On the basis of the above, it is obvious that the second groove 1011 also has an escape space 1012 formed by the active material layer 101 and the first protective layer 13 and for the pole ear 12 to extend into, that is, the second groove 1011 is not only used to set the first protective layer 13, but also forms an escape space 1012 for accommodating the pole ear 12 (based on the pole ear 12 piercing the second protective layer 14 and the isolation film 11), thereby avoiding the increase of the thickness of the battery cell to a certain extent. And the other parts of this embodiment are the same as those of embodiment 1, and will not be repeated here.

[0036] Implementation 3

[0037] The difference between this embodiment and embodiment 1 is that: in order to realize that a second groove 1011 is provided on the active material layer 101 so that the first protective layer 13 can be embedded, thereby ensuring the overall flatness of the welding position of the battery cell tab 12, the second groove 1011 is formed by laser cleaning, mechanical cleaning, or foam cleaning the active material layer 101 and exposing the current collector 100. Preferably, the second groove 1011 is formed by laser cleaning and exposing the active material layer 101. The other parts of this embodiment are the same as those of embodiment 1, and are not described in detail here.

[0038] Implementation 4

[0039] The difference between this embodiment and embodiment 1 is that: Figure 3In order to ensure the protective effect of the first protective layer 13 (preventing the pole ear 12 from piercing the pole piece 10), the first protective layer 13 includes a ceramic layer 130, a colloid layer 131 and a substrate layer 132 attached between the ceramic layer 130 and the colloid layer 131. Among them, the weight of the binder in the ceramic layer 130 accounts for 1% to 75% of the total weight. It should be noted that the ceramic particles include one or more of aluminum oxide, silicon dioxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium dioxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide and barium sulfate. The binder includes one or more of polyvinylidene fluoride, polyacrylic acid, polyacrylate, sodium carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoroethylene and styrene-butadiene rubber. And the other parts of this embodiment are the same as those of embodiment 1, and are not repeated here.

[0040] Implementation method 5

[0041] The difference between this embodiment and embodiment 4 is that: Figure 4 In order to ensure the protective effect of the first protective layer 13 (to prevent the pole ear 12 from piercing the pole piece 10), the first protective layer 13 includes a ceramic layer 130 and a colloid layer 131. In this specific embodiment, the proportion of the binder in the ceramic layer 130 is the same as above. It should be noted that the materials of the ceramic particles and the binder in the ceramic layer 130 can be the same as or different from the above. And the other parts of this embodiment are the same as those in embodiment 4, and will not be repeated here.

[0042] Implementation 6

[0043] The difference between this embodiment and embodiment 4 or embodiment 5 is that: in order to further ensure the protective effect of the first protective layer 13 (to prevent the welding burrs on the pole ear 12 from piercing the pole piece 10), specifically, in order to prevent the first protective layer 13 from having a coating gap after coating due to insufficient thickness of the first protective layer 13, and the welding burrs on the pole ear piercing the pole piece from the coating gap, the thickness of the first protective layer 13 is between 2um and 50um, and the hardness W1 of the ceramic layer 130 in the first protective layer 13 satisfies: 80HRA≤W1≤90HRA, so as to improve the overall hardness of the first protective layer 13 and further block the welding burrs on the pole ear, thereby improving the safety performance of the battery cell. In other words, the hardness value of the first protective layer 13 in the utility model is greater than the hardness value of the conventional protective glue. And the other parts of this embodiment are the same as embodiment 4 or embodiment 5, and will not be repeated here.

[0044] Implementation 7

[0045] The difference between this embodiment and embodiment 6 is that, in order to ensure the hardness of the ceramic layer 130 in the first protective layer 13, the weight of the ceramic particles in the ceramic layer 130 accounts for 20% to 99% of the total weight. The other parts of this embodiment are the same as those in embodiment 6 and will not be described here.

[0046] Implementation 8

[0047] The difference between this embodiment and embodiment 1 is that: in order to prevent a short circuit between the tab and the aluminum-plastic film during battery packaging, and to seal and bond with the aluminum-plastic film by heating during packaging to prevent leakage, the electrode assembly 1 further includes a second protective layer 14 (tab glue), and the second protective layer 14 covers the notch of the first groove 1010. The other parts of this embodiment are the same as those of embodiment 1, and are not described here.

[0048] Implementation method 9

[0049] The difference between this embodiment and the above embodiment is that the present invention further provides a battery, including a packaging shell and the above electrode assembly 1, and the packaging shell is coated on the electrode assembly 1. It should be noted that the battery can be used, manufactured, sold and licensed alone. The other parts of this embodiment are the same as the above embodiment, and will not be repeated here.

[0050] Embodiment 10

[0051] The difference between this embodiment and the above embodiment is that the present invention also provides an electrochemical device, including the above battery. It should be noted that the electrochemical device can be used, manufactured, sold and licensed alone. The other parts of this embodiment are the same as the above embodiment and will not be described in detail here.

[0052] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. An electrode assembly, characterized in that: It comprises a pole piece having a current collector and a first protective layer for preventing a pole ear from piercing the pole piece; A first groove is formed on the active material layer of the current collector, and a second groove is formed on the corresponding active material layer of the current collector in the adjacent pole piece; wherein a pole ear is embedded in the first groove, a first protective layer is embedded in the second groove, and the first groove and the second groove are arranged opposite to each other.

2. The electrode assembly according to claim 1, characterized in that: Along the thickness direction of the electrode assembly, the depth of the second groove is greater than the thickness of the first protective layer, and the projection of the second groove covers the projection of the first groove; The second groove has an escape space formed by the active material layer and the first protective layer and for the tab to extend into.

3. The electrode assembly according to claim 1, characterized in that: The second groove is formed by laser cleaning, mechanical cleaning or foaming glue cleaning the active material layer to expose the current collector.

4. The electrode assembly according to claim 1, characterized in that: The first protective layer includes a ceramic layer, a colloid layer and a substrate layer attached between the ceramic layer and the colloid layer.

5. The electrode assembly according to claim 1, characterized in that: The first protective layer includes a ceramic layer and a colloid layer.

6. The electrode assembly according to claim 4 or 5, characterized in that: The thickness of the first protective layer is between 2um and 50um; and / or the hardness W1 of the ceramic layer in the first protective layer satisfies: 80HRA≤W1≤90HRA.

7. The electrode assembly according to claim 6, characterized in that: The weight of the ceramic particles in the ceramic layer accounts for 20% to 99% of the total weight of the ceramic layer.

8. The electrode assembly according to claim 1, characterized in that: A second protective layer is also included, and the second protective layer covers the notch of the first groove.

9. A battery, characterized in that: The invention comprises a packaging shell and an electrode assembly as claimed in any one of claims 1 to 5, wherein the packaging shell is coated on the electrode assembly.

10. An electrochemical device, characterized in that: Comprising the battery as claimed in claim 9.

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