Tab, battery cell and battery

Abstract

The utility model relates to the technical field of batteries, and discloses a tab, a battery cell and a battery, the tab comprises a first conducting layer, an expansion layer and a second conducting layer which are sequentially connected along the thickness direction, and the expansion layer is used for expanding to push the first conducting layer and the second conducting layer when the temperature reaches a critical temperature; the distance between the first conductive layer and the second conductive layer is increased, and when the tab is applied to a battery cell, the distance between the first conductive layer and the second conductive layer is increased, so that an outer seal of the battery cell can be opened, and the outer seal is opened to form an opening communicated with an external space; and heat and gas generated by high temperature in the battery cell can be discharged through the opening, so that dangerous conditions such as fire, explosion and the like of the battery cell at the high temperature can be avoided, the hot box performance of the battery cell is improved, and the safety and reliability of the battery cell are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a tab, a battery core and a battery. Background Art

[0002] With the continuous advancement and development of lithium-ion battery technology, battery cell safety is receiving increasing attention. Improving the hot-box performance of battery cells can ensure their safety and reliability and reduce potential safety hazards. However, the hot-box performance of battery cells still needs to be improved. Utility Model Content

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a tab that can improve the thermal performance of a battery cell.

[0004] The utility model also provides a battery cell and a battery having the above-mentioned tab.

[0005] According to the electrode tab of the embodiment of the first aspect of the present invention, the electrode tab includes a first conductive layer, an expansion layer and a second conductive layer connected in sequence along the thickness direction, and the expansion layer is used to expand when the temperature reaches a critical temperature to push the first conductive layer and the second conductive layer, thereby increasing the distance between the first conductive layer and the second conductive layer.

[0006] According to the embodiment of the utility model, the electrode ear has at least the following beneficial effects: the electrode ear includes a first conductive layer, an expansion layer and a second conductive layer connected in sequence along the thickness direction, and the expansion layer is used to expand when the temperature reaches a critical temperature to push the first conductive layer and the second conductive layer, so that the distance between the first conductive layer and the second conductive layer is increased. When the electrode ear is applied to the battery cell, the increase in the distance between the first conductive layer and the second conductive layer can stretch the outer seal of the battery cell, so that the outer seal is opened to form an opening connected to the external space. The heat and gas generated by the high temperature inside the battery cell can be discharged through the opening, which helps to avoid dangerous situations such as fire and explosion of the battery cell at high temperature, improves the hot box performance of the battery cell, and improves the safety and reliability of the battery cell.

[0007] According to some embodiments of the present invention, along the thickness direction, the first conductive layer and the second conductive layer have the same thickness.

[0008] According to some embodiments of the present invention, the tab is a positive tab, and along the thickness direction, the thickness of the tab is ≥80μm and ≤100μm, or the tab is a negative tab, and along the thickness direction, the thickness of the tab is ≥60μm and ≤100μm.

[0009] According to some embodiments of the present invention, along the thickness direction, the thickness of the expansion layer is ≥8 μm and ≤30 μm.

[0010] According to some embodiments of the present invention, the critical temperature of the expansion layer is ≥100°C and ≤120°C.

[0011] According to some embodiments of the present invention, the tab further includes an adhesive layer, wherein the adhesive layer is bonded between the first conductive layer and the expansion layer, and / or the adhesive layer is bonded between the second conductive layer and the expansion layer.

[0012] According to some embodiments of the present invention, along the thickness direction, the thickness of the adhesive layer is ≥0.6 μm and ≤1 μm.

[0013] According to the battery cell of the second embodiment of the present utility model, the battery cell includes a main body and the tab in any of the above embodiments, and the tab is connected to the main body.

[0014] According to some embodiments of the present invention, the battery cell further includes an outer seal, the main body is arranged inside the outer seal, and the pole ear portion is exposed outside the outer seal; wherein, the outer seal is suitable for opening as the distance between the first conductive layer and the second conductive layer increases to form an opening connected to the external space.

[0015] According to the battery of the third embodiment of the present utility model, the battery includes the battery cell in any of the above embodiments.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0018] Figure 1 A partial structural schematic diagram of a battery cell provided by an embodiment of the utility model is shown.

[0019] Figure 2 A schematic structural diagram of a battery cell in which a main body and a battery cell are encapsulated in an outer seal is shown in an embodiment of the present utility model.

[0020] Figure 3 Shown Figure 2 Schematic diagram of the battery cell structure after the middle tab expands.

[0021] Figure 4 A schematic structural diagram of a tab provided in an embodiment of the present utility model is shown.

[0022] Reference numerals:

[0023] Battery cell 100;

[0024] Tab 110; positive tab 111; negative tab 113; first conductive layer 115; expansion layer 117; second conductive layer 119; bonding layer 210; insulating adhesive layer 211;

[0025] Main body 130; outer seal 150; opening 151; thickness direction Y. DETAILED DESCRIPTION

[0026] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0027] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0028] In the description of this utility model, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of the terms "first" and "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0029] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0030] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0031] See also Figure 1An embodiment of the present application provides a battery, which includes a battery cell 100 and a shell. The battery cell 100 can be accommodated in the shell, and the shell can be used to protect the battery cell 100.

[0032] Batteries can be used to provide power for new energy vehicles, electronic devices and other equipment.

[0033] See also Figures 1 to 2 In some embodiments, the battery cell 100 includes a main body 130 and a tab 110 . The tab 110 can be connected to the main body 130 . The tab 110 can also be connected to a battery terminal.

[0034] The battery cell 100 may refer to a wound battery cell, a laminated battery cell, a cylindrical battery cell or other battery cells.

[0035] The number of the electrode tabs 110 may be two, one of the two electrode tabs 110 is a positive electrode tab 111 , and the other is a negative electrode tab 113 .

[0036] As an example, taking the battery cell 100 as a wound battery cell, the main body 130 may include a positive electrode sheet, a separator, and a negative electrode sheet, which are stacked and wound to form the main body 130. The positive electrode sheet may be connected to a positive electrode tab 111, which may be electrically connected to the positive electrode post of the battery; the negative electrode sheet may be connected to a negative electrode tab 113, which may be electrically connected to the negative electrode post of the battery.

[0037] The electrode sheet (positive electrode sheet or negative electrode sheet) can adopt a multi-false electrode tab electrode sheet, that is, the electrode sheet can include a base body and a false electrode tab connected to the side of the base body. Taking a wound battery cell as an example, the base body can include straight sections and bent sections alternately distributed along the winding direction. After the electrode sheet is wound, multiple straight sections are stacked along the thickness direction Y of the battery cell 100. Each straight section can be connected to a false electrode tab along the side. After the electrode sheet is wound, some of the false electrode tabs are stacked to form a positive conductive structure, and the other part of the false electrode tabs are stacked to form a negative conductive structure. The positive conductive structure can be electrically connected to the positive electrode tab 111, and the negative conductive structure can be electrically connected to the negative electrode tab 113.

[0038] It is understandable that the electrode may not be provided with a dummy electrode tab, and the electrode tab 110 may be directly connected to the electrode.

[0039] In some embodiments, the battery cell 100 may further include an outer seal 150 , the main body 130 may be disposed within the outer seal 150 , and the tab 110 may be partially exposed from the outer seal 150 to facilitate connection of the tab 110 to a battery terminal.

[0040] As an example, the tab 110 may include an insulating adhesive layer 211. The insulating adhesive layer 211 may be provided on opposite sides of the tab 110 along the thickness direction Y. The insulating adhesive layer 211 may be bonded to the inner surface of the outer seal 150 to fix the tab 110. The insulating adhesive layer 211 may be tab glue.

[0041] It can be understood that the main body 130 and the tab 110 are encapsulated in the outer seal 150 , and after the outer seal 150 is filled with liquid (electrolyte), the outer seal 150 is sealed to prevent leakage of the electrolyte.

[0042] The outer seal 150 may be made of aluminum-plastic film or other materials.

[0043] See also Figures 2 to 3 The tab 110 can be used to expand when the temperature reaches a critical temperature to push the outer seal 150 to open, so that the outer seal 150 can form an opening 151 (such as Figure 3 As shown), the heat and gas generated by the high temperature inside the battery cell 100 can flow to the external space through the opening 151, which helps to avoid dangerous situations such as fire and explosion of the battery cell 100 at high temperature, improves the hot box performance of the battery cell 100, and improves the safety and reliability of the battery cell 100.

[0044] See also Figures 2 to 4 In some embodiments, the tab 110 includes a first conductive layer 115, an expansion layer 117, and a second conductive layer 119 connected in sequence along the thickness direction Y. The expansion layer 117 is used to expand when the temperature reaches a critical temperature to push the first conductive layer 115 and the second conductive layer 119, so that the distance between the first conductive layer 115 and the second conductive layer 119 increases. The outer seal 150 is suitable for opening as the distance between the first conductive layer 115 and the second conductive layer 119 increases to form an opening 151 connected to the external space. The heat and gas inside the battery cell 100 can be discharged through the opening 151, thereby helping to avoid dangerous situations such as fire and explosion of the battery cell 100 at high temperature, improving the hot box performance of the battery cell 100, and improving the safety and reliability of the battery cell 100.

[0045] The first conductive layer 115 and the second conductive layer 119 can both be used to electrically connect the electrode and the battery pole to transmit current.

[0046] As an example, the expansion layer 117 can be bonded between the first conductive layer 115 and the second conductive layer 119, and the first conductive layer 115 and the second conductive layer 119 can be respectively bonded to the inner surfaces on both sides of the outer seal 150. When the temperature of the expansion layer 117 rises to the critical temperature, the expansion layer 117 begins to expand, and the volume of the expansion layer 117 increases, pushing the first conductive layer 115 and the second conductive layer 119 away from each other to increase the distance between the first conductive layer 115 and the second conductive layer 119 along the thickness direction Y. The thickness of the tab 110 increases to open the outer seal 150, so that the outer seal 150 forms an opening 151 connected to the external space. The heat and gas generated by the high temperature inside the battery cell 100 can be discharged through the opening 151.

[0047] In some embodiments, the tab 110 further includes an adhesive layer 210 . The adhesive layer 210 is bonded between the first conductive layer 115 and the expansion layer 117 , which helps to bond and fix the first conductive layer 115 and the expansion layer 117 .

[0048] The adhesive layer 210 may be made of insulating adhesive, for example, the adhesive layer 210 may be made of acrylic adhesive.

[0049] In some embodiments, an adhesive layer 210 may be bonded between the second conductive layer 119 and the expansion layer 117 to help bond and fix the second conductive layer 119 and the expansion layer 117 .

[0050] In some embodiments, along the thickness direction Y, the thickness of the adhesive layer 210 is ≥0.6 μm and ≤1 μm, which helps to control the adhesive layer 210 within an appropriate range and helps to prevent the adhesive layer 210 from affecting the thickness of the conductive layer (the first conductive layer 115 or the second conductive layer 119) and the thickness of the expansion layer 117.

[0051] As an example, the thickness of the adhesive layer 210 may be 0.6 μm, 0.7 μm, 0.8 μm, 1 μm, or other values in the range of [0.6 μm, 1 μm].

[0052] For ease of description, the conductive layer in the following embodiments may refer to the first conductive layer 115 or the second conductive layer 119 .

[0053] In some embodiments, the tab 110 is a positive tab 111, and along the thickness direction Y, the thickness of the tab 110 is ≥80 μm and ≤100 μm. In this way, controlling the thickness of the positive tab 111 within an appropriate range helps to make the conductive layer have sufficient thickness to ensure the current-carrying performance of the conductive layer and reduce the heat generation of the conductive layer. It can also make the expansion layer 117 have sufficient thickness, which helps to ensure the expansion effect of the expansion layer 117, so as to push the two conductive layers apart to a sufficiently long distance, increase the size of the opening 151 of the outer seal 150, and improve the heat dissipation and exhaust effect.

[0054] As an example, when the electrode tab 110 is a positive electrode tab 111 , the thickness of the electrode tab 110 may be 80 μm, 85 μm, 92 μm, 100 μm, or other values in the range of [80 μm, 100 μm].

[0055] In some embodiments, the tab 110 is a negative tab 113, and along the thickness direction Y, the thickness of the tab 110 is ≥60 μm and ≤100 μm. In this way, controlling the thickness of the negative tab 113 within an appropriate range helps to make the conductive layer have sufficient thickness to ensure the current-carrying performance of the conductive layer and reduce the heat generation of the conductive layer. It can also make the expansion layer 117 have sufficient thickness, which helps to ensure the expansion effect of the expansion layer 117, so as to push the two conductive layers apart to a sufficiently long distance, increase the size of the opening 151 of the outer seal 150, and improve the heat dissipation and exhaust effect.

[0056] As another example, when the electrode tab 110 is a negative electrode tab 113 , the thickness of the electrode tab 110 may be 60 μm, 65 μm, 94 μm, 100 μm, or other values in the range of [60 μm, 100 μm].

[0057] In some embodiments, the thickness of the positive electrode tab 111 may be greater than the thickness of the negative electrode tab 113 , which helps to improve the current carrying performance of the positive electrode tab 111 .

[0058] In some embodiments, the first conductive layer 115 and the second conductive layer 119 may be connected or disconnected on both sides of the width direction of the tab 110. When the first conductive layer 115 and the second conductive layer 119 are connected, the expansion layer 117 is encapsulated within the first conductive layer 115 and the second conductive layer 119.

[0059] The width direction of the electrode tab 110 is substantially parallel to the direction from the positive electrode tab 111 to the negative electrode tab 113 , and the width direction of the electrode tab 110 is perpendicular to the thickness direction Y of the electrode tab 110 .

[0060] In some embodiments, both the first conductive layer 115 and the second conductive layer 119 may be metal layers, which helps to improve the current carrying performance of the first conductive layer 115 and the second conductive layer 119 .

[0061] As an example, when the electrode tab 110 is a positive electrode tab 111 , both the first conductive layer 115 and the second conductive layer 119 may be aluminum metal layers.

[0062] As another example, when the electrode tab 110 is the negative electrode tab 113 , both the first conductive layer 115 and the second conductive layer 119 may be copper metal layers or copper-plated nickel metal layers.

[0063] The materials of the first conductive layer 115 and the second conductive layer 119 may be the same or different.

[0064] In some embodiments, along the thickness direction Y, the thickness of the first conductive layer 115 and the second conductive layer 119 are the same, which helps to make the current-carrying performance of the first conductive layer 115 and the second conductive layer 119 roughly the same, and helps to avoid a large difference in temperature rise between the first conductive layer 115 and the second conductive layer 119.

[0065] In some embodiments, along the thickness direction Y, D1 is defined as the thickness of the tab 110 , D2 is defined as the thickness of the expansion layer 117 , the thickness of the two adhesive layers 210 are both D3 , and the thickness of the first conductive layer 115 and the thickness of the second conductive layer 119 are both D4 .

[0066] Wherein, D4=(D1-D2-D3) / 2, so D1, D2, D3, and D4 can be controlled within an appropriate range through the formula.

[0067] In some embodiments, when the critical temperature of the expansion layer 117 is ≥100°C and ≤120°C, that is, when the temperature of the expansion layer 117 reaches a temperature value within the temperature range of [100°C, 120°C], the expansion layer 117 begins to expand, so that the critical temperature can be controlled within a suitable range to prevent the expansion layer 117 from starting to expand in a low temperature environment and affecting the normal operation of the battery.

[0068] The critical temperature can be designed according to the requirements to control the critical temperature within a suitable range. It can be understood that the critical temperature of the expansion layer 117 can be affected by the material, preparation process, etc.

[0069] In some embodiments, the expansion layer 117 may be made of plastic so that the expansion layer 117 can decompose and expand in a high temperature environment.

[0070] In some embodiments, the expansion layer 117 may be made by mixing a polymer material and a foaming agent. The polymer material may begin to melt when the temperature reaches a critical temperature, and the foaming agent may begin to decompose and expand.

[0071] The polymer material may be at least one of polyvinyl chloride, polyester, polyurethane and polysulfide rubber, or the polymer material may be other materials.

[0072] The initial melting temperature of the polymer material may be ≤100° C., that is, when the temperature of the expansion layer 117 approaches 100° C., the polymer material changes from a solid state to a liquid state.

[0073] For example, the critical temperature of the polymer material may be 100° C., 99° C., 97° C., or other temperature values, which can be specifically designed according to requirements.

[0074] The foaming agent can be sodium bicarbonate, ammonium carbonate, ammonium carbonate, ammonium bicarbonate, potassium bicarbonate, ammonium nitrite, potassium borohydride, sodium borohydride, azo derivatives, hydrazine derivatives, semicarbazide, tetrazole compounds, nitroso compounds or other materials.

[0075] The decomposition temperature of the foaming agent may be ≥100°C and ≤120°C, that is, when the temperature of the expansion layer 117 is between the temperature range of [100°C, 120°C], the foaming agent begins to decompose and expand. The decomposition temperature may refer to the critical temperature in the above embodiment.

[0076] It can be understood that the initial melting temperature of the polymer material can be less than or equal to the decomposition temperature of the foaming agent, so that the polymer material can be melted into a liquid state in advance, which helps the foaming agent to decompose and expand more quickly.

[0077] As an example, when the temperature of the expansion layer 117 reaches 100°C, the polymer material melts from solid to liquid, and the foaming agent begins to decompose and expand to increase the thickness of the tab 110, stretching the outer seal 150 so that the outer seal 150 forms an opening 151 to facilitate heat dissipation and exhaust.

[0078] As another example, when the temperature of the expansion layer 117 approaches 100°C, for example, when the temperature of the expansion layer 117 is 99°C, the polymer material initially melts, the foaming agent also begins to gradually decompose and expand, the thickness of the tab 110 gradually increases, and the outer seal 150 is gradually stretched to form an opening 151 for heat dissipation and exhaust. When the temperature of the expansion layer 117 gradually increases to ≥100°C, the polymer material completely transforms from a solid state to a liquid, the foaming agent fully decomposes and expands, further increasing the thickness of the tab 110. Correspondingly, the opening 151 of the outer seal 150 also increases, thereby improving the heat dissipation and exhaust effects.

[0079] In some embodiments, the added content of the foaming agent in the expansion layer 117 is ≥0.3% and ≤3%. In this way, controlling the content of the foaming agent in the expansion layer 117 within an appropriate range helps to ensure the foaming effect of the foaming agent, and can also ensure that the expansion layer 117 contains sufficient polymer materials to ensure the structural strength and physical properties of the expansion layer 117.

[0080] In some embodiments, along the thickness direction Y, the thickness of the expansion layer 117 is ≥8 μm and ≤30 μm. In this way, controlling the thickness of the expansion layer 117 within an appropriate range helps to avoid the conductive layer becoming thinner due to the expansion layer 117 being too thick, thereby affecting the current-carrying performance of the conductive layer. It also helps to avoid the expansion effect of the expansion layer 117 being affected due to the expansion layer 117 being too thin.

[0081] As an example, the thickness of the expansion layer 117 may be 8 μm, 18 μm, 22 μm, 28 μm, 30 μm, or other values in the range [8 μm, 30 μm].

[0082] Preferably, along the thickness direction Y, the thickness of the expansion layer 117 is ≥10 μm and ≤20 μm. This helps to control the thickness of the expansion layer 117 within a more appropriate range, further ensuring the current-carrying performance of the conductive layer and the expansion effect of the expansion layer 117 .

[0083] As an example, the thickness of the expansion layer 117 may be 10 μm, 11 μm, 13 μm, 18 μm, 20 μm, or other values in the range of [10 μm, 20 μm].

[0084] In the tab 110, battery cell 100 and battery provided in the embodiment of the present application, the tab 110 includes a first conductive layer 115, an expansion layer 117 and a second conductive layer 119 connected in sequence along the thickness direction Y. The expansion layer 117 is used to expand when the temperature reaches a critical temperature to push the first conductive layer 115 and the second conductive layer 119, so that the distance between the first conductive layer 115 and the second conductive layer 119 increases. When the tab 110 is applied to the battery cell 100, the increase in the distance between the first conductive layer 115 and the second conductive layer 119 can stretch the outer seal 150 of the battery cell 100, so that the outer seal 150 opens to form an opening 151 connected to the external space. The heat and gas generated by the high temperature inside the battery cell 100 can be discharged through the opening 151, thereby helping to avoid dangerous situations such as fire and explosion in the battery cell 100 at high temperature, improving the hot box performance of the battery cell 100, and improving the safety and reliability of the battery cell 100.

[0085] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. In addition, the embodiments of the present invention and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A tab, characterized in that: The tab includes a first conductive layer, an expansion layer, and a second conductive layer connected in sequence along the thickness direction. The expansion layer is used to expand when the temperature reaches a critical temperature to push the first conductive layer and the second conductive layer, thereby increasing the distance between the first conductive layer and the second conductive layer.

2. The tab according to claim 1, wherein: Along the thickness direction, the first conductive layer and the second conductive layer have the same thickness.

3. The tab according to claim 1, wherein: The tab is a positive tab, and along the thickness direction, the thickness of the tab is ≥80 μm and ≤100 μm, or the tab is a negative tab, and along the thickness direction, the thickness of the tab is ≥60 μm and ≤100 μm.

4. The tab according to claim 1, wherein: Along the thickness direction, the thickness of the expansion layer is ≥8 μm and ≤30 μm.

5. The tab according to claim 1, wherein: The critical temperature of the expansion layer is ≥100°C and ≤120°C.

6. The tab according to claim 1, wherein: The tab further includes an adhesive layer, wherein the adhesive layer is bonded between the first conductive layer and the expansion layer, and / or the adhesive layer is bonded between the second conductive layer and the expansion layer.

7. The tab according to claim 6, characterized in that: Along the thickness direction, the thickness of the adhesive layer is ≥0.6 μm and ≤1 μm.

8. A battery cell, characterized in that: include: main body; as well as The tab according to any one of claims 1 to 7, wherein the tab is connected to the main body.

9. The battery cell according to claim 8, characterized in that The battery cell further includes an outer seal, the main body is arranged in the outer seal, and the tab portion is exposed outside the outer seal; The outer seal is adapted to expand as the distance between the first conductive layer and the second conductive layer increases to form an opening communicating with an external space.

10. A battery, characterized in that: Comprising the battery cell according to any one of claims 8 to 9.

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